ARTICLE | doi:10.20944/preprints202010.0183.v2
Subject: Materials Science, Surfaces, Coatings & Films Keywords: tin oxide; thin films; atmospheric pressure chemical vapour deposition transport properties; magnetoresistance; impedance spectroscopy; charge carrier mobility
Online: 8 June 2021 (13:55:21 CEST)
Transparent conducting oxides (TCO) with high electrical conductivity and at the same time high transparency in the visible spectrum are an important class of materials widely used in many devices requiring a transparent contact such as light-emitting diodes, solar cells and display screens. Since the improvement of electrical conductivity usually leads to degradation of optical transparency, a fine-tuning sample preparation process and a better understanding of the correlation between structural and transport properties is necessary for optimizing the properties of TCO for use in such devices. Here we report a structural and magnetotransport study of tin oxide (SnO2), a well-known and commonly used TCO, prepared by a simple and relatively cheap Atmospheric Pressure Chemical Vapour Deposition (APCVD) method in the form of thin films deposited on soda-lime glass substrates. The thin films were deposited at two different temperatures (which were previously found to be close to optimum for our setup), 590 °C and 610 °C, and with (doped) or without (undoped) the addition of fluorine dopants. Scanning Electron Microscopy (SEM) and Grazing Incidence X-ray Diffraction (GIXRD) revealed the presence of inhomogeneity in the samples, on a bigger scale in form of grains (80–200 nm), and on a smaller scale in form of crystallites (10–25 nm). Charge carrier density and mobility extracted from DC resistivity and Hall effect measurements were in the ranges 1–3 × 1020 cm−3 and 10–20 cm2/Vs, which are typical values for SnO2 films, and show a negligible temperature dependence from room temperature down to -269 °C. Such behaviour is ascribed to grain boundary scattering, with the interior of the grains degenerately doped (i.e., the Fermi level is situated well above the conduction band minimum) and with negligible electrostatic barriers at the grain boundaries (due to high dopant concentration). The observed difference for factor 2 in mobility among the thin-film SnO2 samples most likely arises due to the difference in the preferred orientation of crystallites (texture coefficient).
ARTICLE | doi:10.20944/preprints202212.0197.v1
Subject: Engineering, Civil Engineering Keywords: fleet structure; road transport; fuzzy logic; transport efficiency
Online: 12 December 2022 (09:13:26 CET)
The estimation of the efficiency of road transport vehicles remains a significant problem for contemporary transport companies, as the technological process is influenced by numerous stochastic impacts, such as demand stochasticity, road conditions uncertainty, transport market fluctuations, etc. To consider the uncertainty related to the estimation of the vehicles’ fleet efficiency, we propose a fuzzy-logic approach, where the efficiency of a given vehicle is described by a membership function. The efficiency of the whole fleet and its rational structure in that case can be evaluated as a fuzzy set. To demonstrate the developed approach, we depict a case study of using cargo vehicles for deliveries of agricultural products in the Republic of Kazakhstan. The numeric results are presented for the selected models of vehicles that a transport company uses to service a set of clients located in Northern Kazakhstan.
ARTICLE | doi:10.20944/preprints201809.0172.v1
Online: 10 September 2018 (13:08:41 CEST)
Given the persistence of microplastics in the environment and their potential toxicity to ecosystems, understanding of likely microplastic accumulation ‘hotspots’ in rivers is urgently needed. To contribute to this challenge, this paper reports results of a microplastic survey from a heavily urbanised catchment, the River Tame, which flows through the city of Birmingham, UK. All sediment sampled was found to contain microplastics with an average abundance of 165 particles kg-1. While urban areas generally have a greater abundance of microplastics as compared with rural, there is no simple relationship between microplastic numbers and population density or proximity to wastewater treatment sites. The greatest change in microplastic abundance was due to the presence of a lake along the course of the River Tame i.e. on entering the lake flow velocities are reduced which promotes the deposition of fine sediment and potentially microplastics. This suggests that the greatest concentrations of microplastics will not be found in-channel but rather on the floodplain and other low velocity environments such as meander cutoffs. We also identified a new mechanism of microplastic fixation in freshwater environments through ecological engineers, specifically caddisfly that incorporated microplastics into their casing. These results highlight the need to explore further hydrodynamic and ecological impacts on microplastics fate and transport in rivers.
ARTICLE | doi:10.20944/preprints202204.0131.v1
Subject: Behavioral Sciences, Other Keywords: Air quality; Geolife; Olympics; Traffic demand; Transport planning; Transport regulation
Online: 14 April 2022 (10:25:45 CEST)
Over the years, researchers have been studying the effect of weather and context data on the transport mode choice. The majority of these works are based on survey data, however the accuracy of their findings relies on how respondents give accurate and honest answers. In this paper, the potential of using GPS trajectories as an alternative to travel surveys in studying the impact of weather and context data on transport mode choices is investigated in Beijing city. In the analysis, we apply both descriptive and statistical models such as the MNL and MNP models. Our findings indicate that temperature has the most prominent effect among weather conditions. For instance, for temperatures greater than 25 °C, the walking share increases by 27% and the bike share reduces by 21%, which is line with the results from several survey studies. In addition, the evidence of government policy on transport regulation is revealed when the air quality becomes hazardous as people are encouraged to use environmentally friendly travel mode choices such as the bike instead of the bus and car, which are known CO2 emitters. Moreover, due to a series of traffic restrictions introduced by the Beijing government during the 2008 summer Olympics, a decrease of 17.5% in the car share and an increase of 13% and 10% in the walking and bus shares, respectively are observed. These findings provide a scientific basis for effective transport regulation and planning purposes.
REVIEW | doi:10.20944/preprints202011.0227.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Organelle transport; Charcot-Marie-Tooth; Axonal transport deficiency; Neurodegeneration; Cytoskeleton; Mitochondria
Online: 6 November 2020 (08:55:15 CET)
Charcot-Marie-Tooth (CMT) disease is the most commonly inherited neurological disorder, defined by progressive deterioration of the peripheral nerves. Clinical manifestations of CMT mutations are typically limited to peripheral neurons, the longest cells in the body. Currently, mutations in at least 80 different genes are associated with CMT and new mutations are regularly being discovered. A large portion of the proteins mutated in axonal CMT have documented roles in mitochondrial mobility. This suggests that trafficking defects may be a common underlying mechanism in CMT. This review will focus on the potential role of altered mitochondrial mobility in the pathogenesis of axonal CMT, highlighting the challenges and opportunities to this “impaired mobility” model of the disease.
ARTICLE | doi:10.20944/preprints202108.0530.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: graphene; electronic transport; Raman
Online: 27 August 2021 (17:03:07 CEST)
We report morpho-structural properties and charge conduction mechanisms of a foamy “graphene sponge”, having a density as low as ≈ 0.07 kg/m3 and a carbon to oxygen ratio C:O ≃ 13:1. The spongy texture analysed by scanning electron microscopy is made of irregularly-shaped millimetres-sized small flakes, containing small crystallites with a typical size of ≃ 16.3 nm. A defect density as high as ≃ 2.6×1011 cm−2 has been estimated by the Raman intensity of D and G peaks, dominating the spectrum from room temperature down to ≃ 153 K. Despite the high C:O ratio, the graphene sponge exhibits an insulating electrical behavior, with a raise of the resistance value at ≃ 6 K up to 5 orders of magnitude with respect to the room temperature value. A variable range hopping (VRH) conduction, with a strong 2D character, dominates the charge carriers transport, from 300 K down to 20 K. At T< 20 K, graphene sponge resistance tends to saturate, suggesting a temperature-independent quantum tunnelling. The 2D-VRH conduction originates from structural disorder and is consistent with hopping of charge carriers between sp2 defects in the plane, where sp3 clusters related to oxygen functional groups act as potential barriers.
ARTICLE | doi:10.20944/preprints201801.0211.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: membrane transport; osmosis; interaction
Online: 23 January 2018 (06:43:31 CET)
A membrane can be represented by an energy landscape that solutes or colloids must cross. A model accounting for the momentum and the mass balances on the membrane energy landscape establishes a new way of writing for the Darcy law. The counter pressure in the Darcy law is no longer written as the result of an osmotic pressure difference but rather as a function of colloid-membrane interactions. The ability of the model to describe the physics of the filtration is discussed in detail. This model is solved on a simplified energy landscape to derive analytical relationships that describe the selectivity and the counter pressure from ab-initio operating conditions. The model shows that the stiffness of the energy landscape has an impact on the process efficiency: a gradual increase in interactions (like with hourglass pore shape) can reduce the separation energetic cost. It allows the introduction of a new paradigm to increase membrane efficiency: the accumulation that is inherent to the separation must be distributed across the membrane. Asymmetric interactions thus lead to direction-dependent transfer properties and the membrane exhibits diode behavior. These new transfer opportunities are discussed.
ARTICLE | doi:10.20944/preprints201704.0043.v1
Online: 7 April 2017 (11:57:46 CEST)
Analytical channel design tools have not advanced appreciably in the last decades, and continue to produce designs based upon a single representative discharge that may not lead to overall sediment continuity. It is beneficial for designers to know when a simplified design may be problematic and to efficiently produce alternative designs that approximate sediment balance over the entire flow regime. The Capacity/Supply Ratio (CSR) approach, an extension of the Copeland method of analytical channel design for sand channels, balances the sediment transport capacity of a design reach with the sediment supply of a stable upstream reach over the entire flow duration curve (FDC) rather than just a single discharge. Although CSR has a stronger physical basis than previous analytical channel design approaches, it has not been adopted in practice because it can be a cumbersome and time-consuming iterative analysis without the use of software. We investigate eighteen sand-bed rivers in a comparison of designs based on the CSR approach and five single-discharge metrics: the effective discharge (Qeff), the 1.5-year recurrence interval discharge (Q1.5), the bankfull discharge (Qbf), and the discharges associated with 50th (Qs50) and 75th (Qs75) percentiles of the cumulative sediment yield curve. To facilitate this analysis we developed a novel design tool using the Visual Basic for Applications (VBA) programming language in Excel® to produce stable channel slope-width combinations based on the CSR methodology for both sand- and gravel-bed streams. The CSR Stable Channel Design Tool’s (CSR Tool) code structure was based on Copeland’s method in SAM and HEC-RAS (Hydrologic Engineering Center’s River Analysis System) and was tested with a single discharge to verify outputs. The Qs50 and Qs75 single-discharge designs match the CSR output most closely, followed by the Qbf, Qeff, and Q1.5. The Qeff proved to be the most inconsistent design metric because it can be highly dependent on the binning procedure used in the effectiveness analysis. Furthermore, we found that the more rigorous physical basis of the CSR analysis is potentially most important in designing ‘labile’ channels with highly erodible substrate, high perennial flow ‘flashiness,’ low width-to-depth ratio, and high incoming sediment load. The CSR Tool provides a resource for river restoration practitioners to efficiently utilize in-depth design techniques that can promote sediment balance in dynamic fluvial systems.
ARTICLE | doi:10.20944/preprints201705.0185.v1
Subject: Social Sciences, Political Science Keywords: transport policy; ASEAN countries; low-carbon transport; comparative analysis; climate change mitigation
Online: 25 May 2017 (08:30:52 CEST)
Emerging countries in Southeast Asia are facing considerable challenges in addressing rising motorisation and its negative impact on air quality, traffic, energy security, liveability, and greenhouse gas emissions. Indeed, even as initial policies to address these issues are being agreed and implemented, current trends are incompatible with sustainable development and long-term climate change targets. This paper presents a comparative analysis of the approach and status of sustainable, low-carbon transport policy in ASEAN countries and identifies differences and similarities, with the aim of helping assessment of feasibility of future policies and informing future studies on policy innovations and cross-country learning. The methodology is based on the taxonomy of policy components developed by Howlett and Cashore, and our data on comprehensive country studies for Indonesia, the Philippines, Thailand and Vietnam and interviews. We find that each country has a specific set of goals, objectives and targets that support sustainable transport, and, directly or indirectly, climate change mitigation. In terms of specific instruments and calibrations, which we analyse based on the Avoid-Shift-Improve approach, there are notable differences between the countries, for example in fuel economy policy.
ARTICLE | doi:10.20944/preprints201804.0024.v1
Subject: Earth Sciences, Environmental Sciences Keywords: pollutant transport modelling; metals transport modelling; free surface water bodies; toxics-reaction equation
Online: 2 April 2018 (11:27:40 CEST)
This paper describes the development of a two-dimensional water quality model that solves hydrodynamic equations tied to transport equations with reactions mechanisms inherent in the processes. This enable us to perform an accurate assessment of the pollution in a coastal ecosystem. The model was developed with data drawn from the ecosystem found in Mexico's southeast state of Tabasco. The coastal ecosystem consists of the interaction of El Yucateco lagoon with the Chicozapote and Tonalá rivers, that connect the lagoon with the Gulf of Mexico. We present the results of pollutants transport simulation in the coastal ecosystem, focusing on toxic parameters for two hydrodynamic scenarios: wet and dry seasons. As it of interest in the zone, we study the transport of four metals: Cadmium, Chromium, Nickel and Lead. In order to address our objectives we solved numerically a self-posed mathematical problem,which is based on the measured data. The performed simulations show to characterise metal transport within the acceptable range of accuracy and in accordance with the measured data. The performed simulations show to characterise metals transport with an acceptable accuracy, agreeing well with measured data in total concentrations in four control points along the water body. Although for the accurate implementation of the hydrodynamic-based water quality model herein presented, boundary (geometry, tides, wind, etc.) and initial (concentrations measurements) conditions are required, it poses as an excellent option when the distribution of solutes with high accuracy is required, easing environmental, economic and social management of coastal ecosystems.
REVIEW | doi:10.20944/preprints202105.0084.v1
Subject: Medicine & Pharmacology, Allergology Keywords: peritoneal, HIPEC, intraperitoneal, drug transport
Online: 6 May 2021 (12:58:55 CEST)
With increasing awareness amongst physicians and improved radiological imaging techniques, the peritoneal cavity is increasingly recognized as an important metastatic site in various malignancies. Prognosis of these patients is usually poor as traditional treatment including surgical resection or systemic treatment is relatively ineffective. Intraperitoneal delivery of chemotherapeutic agents is thought to be an attractive alternative as this results in high tumor tissue concentrations with limited systemic exposure. The addition of hyperthermia aims to potentiate the anti-tumor effects of chemotherapy, resulting in the concept of heated intraperitoneal chemotherapy (HIPEC) for the treatment of peritoneal metastases as it was developed about 3 decades ago. With increasing experience, HIPEC has become a safe and accepted treatment offered in many centers around the world. However, standardization of the technique has been poor and results from clinical trials have been equivocal. As a result, the true value of HIPEC in the treatment of peritoneal metastases remains a matter of debate. The current review aims to provide a critical overview of the theoretical concept and preclinical and clinical study results, to outline areas of persisting uncertainty, and to propose a framework to better define the role of HIPEC in the treatment of peritoneal malignancies.
ARTICLE | doi:10.20944/preprints202103.0594.v1
Online: 24 March 2021 (14:02:33 CET)
We propose a geographical time-space model extending time-space relief cartography introduced by Mathis and L’Hostis [,,,]. The novelty of the model resides in the use of cones to describe the terrestrial surface instead of graph faces, and in the use of curves instead of broken segments for edges. The approach lies a the intersection of two domains involving graphic representation: cartography, and three dimensional computer graphics. We implement the model on the Chinese space. The Chinese geographical time-space of the reference year 2006 is produced by the combination and the confrontation of the fast air transport system and of the 7.5 times slower road transport system. Slower, short range flights are represented as curved lines above the earth surface with longer length than the geodesic, in order to account for a slower speed. The very steep slope of cones expresses the relative difficulty of crossing terrestrial time-space, as well as the comparably extreme efficiency of long-range flights for moving between cities. Finally, the whole image proposes a coherent representation of the geographical time-space where fast city to city transport is combined with slow terrestrial systems that allow to reach any location.
REVIEW | doi:10.20944/preprints202111.0482.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Solute Transport; Bio-geo-chemical reactions; Dispersion; Mixing; Heterogeneity; Effective transport; Microbial communities, Biofilms
Online: 25 November 2021 (15:53:41 CET)
Reactive transport (RT) couples bio-geo-chemical reactions and transport. RT is important to understand numerous scientific questions and solve some engineering problems. RT is highly multidisciplinary, which hinders the development of a body of knowledge shared by RT modelers and developers. The goal of this paper is to review the basic conceptual issues shared by all RT problems, so as to facilitate advance along the current frontier: biochemical reactions. To this end, we review the basic equations to point that chemical systems are controlled by the set of equilibrium reactions, which are easy to model, but whose rate is controlled by mixing. Since mixing is not properly represented by the standard advection-dispersion equation (ADE), we conclude that this equation is poor for RT. This leads us to review alternative transport formulations, and the methods to solve RT problems using both the ADE and alternative equations. Since equilibrium is easy, difficulties arise for kinetic reactions, which is especially true for biochemistry, where numerous frontiers are open (how to represent microbial communities, impact of genomics, effect of biofilms on flow and transport, etc.). We conclude with the basic 10 issues that we consider fundamental for any conceptually sound RT effort.
ARTICLE | doi:10.20944/preprints202101.0117.v1
Subject: Materials Science, Biomaterials Keywords: Thermal transport in nanocomposites; interfacial thermal conductance; graphene; borophene; multiscale modelling of thermal transport
Online: 6 January 2021 (13:26:46 CET)
Graphene and borophene are highly attractive two-dimensional materials with outstanding physical properties. In this study we employed a combined atomistic continuum multiscale modeling to explore the effective thermal conductivity of polymers nanocomposites made of PDMS polymer as the matrix and graphene and borophene as nanofillers. We first conduct classical molecular dynamics simulations to investigate the interfacial thermal conductance between graphene/PDMS and borophene/PDMS interfaces. Acquired results confirm that the interfacial thermal conductance between nanosheets and polymer increases from the single-layer to multilayered nanosheets and finally converges. The data provided by the atomistic simulations were then used in the finite element method simulations to evaluate the effective thermal conductivity of polymer nanocomposites at continuum level. We explore the effects of nanofillers type, their volume content, geometry aspect ratio and thickness on the nanocomposites effective thermal conductivity. As a very interesting finding, we show that borophene nanosheets, despite almost two orders of magnitude lower thermal conductivity than graphene, can yield very close enhancement in the effective thermal conductivity in comparison with graphene, particularly for low volume content and small aspect ratios and thicknesses. We conclude that for the polymer-based nanocomposites, significant improvement in the thermal conductivity can be reached by improving the bonding between the fillers and polymer or in another word enhancing the thermal conductance at the interface. By taking into account the high electrical conductivity of borophene, our results suggest borophene nanosheets as promising nanofillers to simultaneously enhance the polymers thermal and electrical conductivity.
Subject: Biology, Physiology Keywords: Plant water transport, plant long-distance water transport, sorption hypothesis, cohesion theory, cohesion-tension theory
Online: 12 April 2019 (20:55:26 CEST)
In the case of vascular plants the process of water loss by leafs and water absorption by the root is well known. There is agreement on the passive nature of long-distance moisture movement in the dead cells of the xylem; however, controversy exists focusing on the long-distance water transport principle. Hales (1726) founded a view of bulk flow based on water suction after experiments with cut twigs. The previous doctrine of long-distance water transport within vessel elements and tracheid of the xylem of intact plants – the relevant cohesion theory in text books – was developed mainly by Boehm (1893), Renner (1911) and Dixon (1914) with plant artefacts. Water movement according to this theory is based on an assumed hydrodynamic bulk fluid flow in xylem in continuous water columns (free of water vapour space), under tension, according to the law of Poiseuille (see e.g. Dixon 1914). Physically hydrodynamics is part of fluid mechanics, as a result Poiseuille’s law is usually valid only for hydrodynamic bulk flow in ideal capillaries (Sutera & Skalak, 1993). Besides the basic requirement for transport, according to cohesion theory, the existence of ideal capillaries is not compatible with either: “Because vessel elements and tracheid do not stand as ideal capillaries. …” (Bresinsky et al. 2008, translated from German). Unlike ideal capillaries, the walls of vessel elements and tracheid interact with the transported water. These walls are able to function as a source or as a sink for the transported water because of interaction with the cell walls. With the interaction, vessel elements and tracheid, part of the xylem, can shrink and swell, unlike ideal capillaries. Because the xylem (in woody plants part of the wood) is inconsistent with the basic law of fluid flow, the equation of mass balance (Zimmermann et al. 2004) and cohesion theory are not strictly followed.Many plant physiologists view the cohesion theory as appropriate, however, this theory remains controversial, i.e. by Eisenhut (1988), Laschimke (1990) and Hahn (1993). Nultsch (1996) gives doubts referring to the present doctrine of plant water transport. Zimmermann et al. (2004) reject the cohesion theory and conclude: “... that the arguments of the proponents of the Cohesion Theory are completely misleading” (Zimmermann et al. 2004). Hence cohesion theory can be treated as inapplicable and the question arises: how does water transport in fact function? In the following, it is gone into in more detail. A sorption hypothesis of actual water transport, based on empirical fact, shall be addressed in this paper.
ARTICLE | doi:10.20944/preprints202107.0552.v1
Online: 23 July 2021 (22:17:49 CEST)
Despite several decades of research, the physics underlying translation – protein synthesis at the ribosome – remains poorly studied. For instance, the mechanism coordinating various events occurring in distant parts of the ribosome is unknown. Very recently, we have suggested that this allosteric mechanism could be based on the transport of electric charges (electron holes) along RNA molecules and localization of these charges in the functionally important areas; this assumption was justified using tRNA as an example. In this study, we turn to the ribosome and show computationally that holes can also efficiently migrate within the whole ribosomal small subunit (SSU). The potential sites of charge localization in SSU are revealed, and it is shown that most of them are located in the functionally important areas of the ribosome – intersubunit bridges, Fe4S4 cluster and the pivot linking the SSU head to the body. As a result, we suppose that hole localization within the SSU can affect intersubunit rotation (ratcheting) and SSU head swiveling, in agreement with the scenario of electronic coordination of ribosome operation. We anticipate that our findings will improve the understanding of the translation process and advance the molecular biology and medicine.
ARTICLE | doi:10.20944/preprints202107.0226.v1
Online: 9 July 2021 (13:55:49 CEST)
Public Transport has been seen since ages as the most environmentally sustainable mode of transport. The users of public transport are diverse and have different socio-economic character. Hence the public transport which is not only supposed to be environmentally sustainable but also envisaged to ensure equity amongst various stakeholders of society like the females, elderly and other vulnerable groups through its service. Gender in binary terms of being differentiated based on men and women is a social construct. Public transport systems in developing countries like India witness socio-cultural factors that shape the experience of women in public spaces by social norms extant in society. Along with this, gender-based issues related to public transport are social and behavioural shortcomings as a consequence of a lack of gender sensitivity. On similar lines, elderly have a negative experience involving safety threats, physical and psychological discomfort while accessing public transport systems. The literature published regarding such issues on the gender and elderly question in public transport systems have been studied and has been brought forth under a stand- alone narrative literature review. A literature review is a prerequisite to conducting either stand-alone reviews or as a preliminary study to be supported with quantitative or qualitative analysis. Here, a stand-alone literature review concerning issues in the public transport system in India has been performed. A narrative type of review is conducted to provide an overview of pre- existing published literature. Narrative overviews are useful educational articles as they help present a broad perspective on a topic and often define the development of a problem and/or ways to manage it. The semi-systematic or narrative-review approach is designed for topics that have been theorized differently and studied within diverse disciplines making it unfavourable to study under a full systematic-review process which majorly caters to reviewing quantitative researches. As narrative-styled literature reviews prefer a semi- systematic data collection method, utmost care has been taken to include perspectives from diverse disciplines. The scope of this review is restricted to summarizing the Indian policies, schemes of public transport in light of socio-equity consideration while narrowing the inherent discrepancies within the socio-cultural ethos of the Indian society which influences socio-equity consideration in public spaces in general and the modes of public transport in particular. Research articles from electronic databases were selected based on relevance to understand the issues this viewpoint, their essential findings and possible recommendations are formulated to provide a comprehensive summary of previous researches.
Subject: Engineering, Automotive Engineering Keywords: Human factor; hazardous materials; transport; safety
Online: 9 June 2021 (10:49:20 CEST)
The article discusses the issues related to the safety of transport of dangerous goods by road. Research on accidents in transport unambiguously points to the human factor, which is most responsible for causing the accident. Determining the causes of driver unreliability in the hu-man-vehicle-environment system requires thorough research. Unfortunately, in this case, experimental research with human involvement is limited in scope. This leaves modeling and simulation of the behavior of the human factor, i.e., the driver transporting dangerous goods. The human being, due to its complexity, is a challenging element to parameterize. The literature presents various attempts to model human actions. In their work, the authors used heuristic methods, specifically fuzzy set techniques, to build a human factor model. In these models, human actions were specified using a verbal or linguistic description. The specificity of fuzzy sets allows to "naturally" limit the "precision" in describing human behavior. The model was built based on the author's questionnaire and expert research, based on which individual features were selected. Then, the traits were assigned appropriate states. The output parameter of the model is λL - the intensity of human error. The obtained values of the intensity of the accident caused by the driver's error were implemented into the author's method of risk assessment. They constituted one of the factors determining the probability of an accident in the transport of dangerous goods, which allowed to determine the optimal route of transport of these goods characterized by the lowest risk of an undesirable event on the route. The article presents the model's assumptions, structure, and features included in the model, which have the most significant influence on shaping the intensity of human error. The results of the simulation studies showed a diversified effect of the analyzed characteristics on the driver's efficiency.
ARTICLE | doi:10.20944/preprints202105.0698.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: Accidents, Data Analysis, Machine Learning, Transport
Online: 28 May 2021 (11:59:24 CEST)
Daily thousands of people and goods move along Brazilian Federal highways. Traffic accidents are numerous on these highways and have a significant impact, whether on the economy or the health system. Identifying predictor variables, the probability of an event occurring and how to mitigate them are of paramount importance for the actions of the transit authorities that manage these roads. The main contribution of this study is the development of a predictive machine learning model which uses open data to shows graphically the critical points in the highways. This model is fully reproducible and can be applied to any region worldwide helping to minimize the number of accidents and to prevent deaths by automotive collisions. For this study, 43 variables were analyzed supporting the identification of the causes of accidents with fatal victims on the main highways in the south of Brazil. RoadLytics is proposed as a supervised machine learning model, using the Random Forest algorithm to analyze about 33 thousand occurrences between 2017 and 2020. An exploratory analysis of the data was carried out to support the modeling and to facilitate data visualization. In this sense, heat maps were developed to support the analysis and identification of potential risk areas. The results show that BR386 highway registers the highest number of fatal occurrences, regardless of the season. Additionally, concerning the weather conditions, the analysis shows that 52% of accidents occurred in favorable conditions, such as clear skies, victimizing 501 people. The driver’s lack of attention is the main reason for the accidents’ occurrences. Applying the developed model, an accuracy of 77% was achieved for the classification of fatal accidents.
ARTICLE | doi:10.20944/preprints202103.0686.v1
Subject: Medicine & Pharmacology, Allergology Keywords: thyroid hormone; transport; thyroid axis; autoimmunity
Online: 29 March 2021 (12:01:12 CEST)
The monocarboxylate transporters 8 (MCT8) and 10 (MCT10) are important for thyroid hormone (TH) uptake and signaling. Reduced TH activity is associated with impaired development, weight gain and discomfort. We hypothesized that autoantibodies (aAb) to MCT8 or MCT10 are prevalent in thyroid disease and obesity. Analytical tests for MCT8-aAb and MCT10-aAb were developed and characterized with commercial antiserum. Serum samples from healthy controls, thyroid patients and young overweight subjects were analyzed, and prevalence of the aAb was compared. MCT8-aAb were additionally tested for biological effects on thyroid hormone uptake in cell culture. Positive MCT8-aAb and MCT10-aAb were detected in all three clinical cohorts analyzed. MCT8-aAb were most prevalent in thyroid patients (11.9%) as compared to healthy controls (3.8%) and overweight adolescents (4.2%). MCT8-aAb positive serum reduced T4 uptake in cell culture in comparison to MCT8-aAb negative control serum. Prevalence of MCT10-aAb was highest in the group of thyroid patients as compared to healthy subjects or overweight adolescents (9.0% versus 4.5% and 6.3%, respectively). We conclude that MCT8 and MCT10 represent autoantigens in humans, and that MCT8-aAb may interfere with regular TH uptake and signaling. The increased prevalence of MCT8-aAb and MCT10-aAb in thyroid disease suggests that their presence may be of pathophysiological relevance. This hypothesis deserves an analysis in large prospective studies.
ARTICLE | doi:10.20944/preprints202003.0385.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Microplastics; transport; TWP; BWP; remote regions
Online: 27 March 2020 (12:20:27 CET)
In recent years, marine, freshwater and terrestrial pollution with microplastics has been discussed extensively, whereas atmospheric microplastic transport has been largely overlooked. Here, we present the first global simulation of atmospheric transport of microplastic particles produced by road traffic (TWPs – tire wear particles and BWPs – brake wear particles), a major source that can be quantified relatively well. We find a high transport efficiency of these particles to remote regions, such as the Arctic Ocean (14%). About 34% of the emitted coarse TWPs and 30% of the emitted coarse BWPs (100 kt yr-1 and 40 kt yr-1 respectively) were deposited in the World Ocean. These amounts are of similar magnitude as the total estimated terrestrial and riverine transport of TWPs and fibres to the ocean (64 kt yr-1). Atmospheric transport of microplastics is thus an underestimated threat to global terrestrial and marine ecosystems and affects air quality on a global scale, especially considering that other large but highly uncertain emissions of microplastics to the atmosphere exist. High latitudes and the Arctic are highlighted as an important receptor of mid-latitude emissions of road microplastics, which may imply a future climatic risk, considering their affinity to absorb solar radiation and accelerate melting.
ARTICLE | doi:10.20944/preprints201904.0198.v1
Subject: Engineering, Civil Engineering Keywords: sustainable development; active transport; visioning; policy
Online: 17 April 2019 (06:19:52 CEST)
This paper sets out three visions for the year 2035 which bring about a radical change in the level of walking, cycling and public transport in Turkish urban areas. A participatory visioning technique was structured according to a three-stage technique: (i) Extensive online comprehensive survey. In which potential transport measures were researched for their relevance to promoting sustainable transport in future Turkish urban areas; (ii) Semi-structured interviews. Where transport strategy suggestions were developed in the context of the possible imaginary urban areas and their associated contextual description of the imaginary urban areas for each vision; (iii) Participatory workshops. Where an innovative method was developed to explore various creative future choices and alternatives. Overall, this paper indicates that the content of the visions was reasonable, but such visions need a considerable degree of consensus and radical approaches to tackling them.
ARTICLE | doi:10.20944/preprints201811.0411.v1
Subject: Materials Science, Nanotechnology Keywords: perovskites; neodymium; luminescence; electric transport; magnetization
Online: 19 November 2018 (03:54:34 CET)
Nanocrystalline La1-xNdxFeO3 powders with different concentrations of Nd3+ have been synthesized by modified Pechini method. Their structure was studied by X-ray powder diffraction (XRD). Further, La1-xNdxFeO3 nanoceramics were prepared by high pressure sintering technique. The luminescence spectra of the powders were investigated as a function of concentration of active dopant to check the possible energy transfers observed due to Nd3+ concentration changes. The electrical and magnetic properties of the powders and ceramics were investigated to determine the effect of Nd3+ doping on the dielectric permittivity and magnetization in the wide frequency range.
ARTICLE | doi:10.20944/preprints201807.0371.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: molecular simulation; membrane separations; ion-transport
Online: 20 July 2018 (04:24:45 CEST)
In this report we have discussed the important role of molecular modeling, especially the use of the molecular dynamics method, in investigating transport processes in nanoporous materials such as membranes. With the availability of high performance computers, molecular modeling can now be used to study rather complex systems at a fraction of the cost or time requirements of experimental studies. Molecular modeling techniques have the advantage of being able to access spatial and temporal resolution which are difficult to reach in experimental studies. For example, sub-Angstrom level spatial resolution is very accessible as is sub-femtosecond temporal resolution. Due to these advantages, simulation can play two important roles: Firstly because of the increased spatial and temporal resolution, it can help understand phenomena not well understood. As an example, we discuss the study of reverse osmosis processes. Before simulations were used it was thought the separation of water from salt was purely a coulombic phenomenon. However, by applying molecular simulation techniques, it was clearly demonstrated that the solvation of ions made the separation in effect a steric separation and it was the flux which was strongly affected by the coulombic interactions between water and the membrane surface. Additionally, because of their relatively low cost and quick turnaround (by using multiple processor systems now increasingly available) simulations can be a useful screening tool to identify membranes for a potential application. To this end, we have described our studies in determining the most suitable zeolite membrane for redox flow battery applications. As computing facilities become more widely available and new computational methods are developed, we believe molecular modeling will become a key tool in the study of transport processes in nanoporous materials.
ARTICLE | doi:10.20944/preprints201806.0476.v1
Subject: Engineering, Energy & Fuel Technology Keywords: biodiesel,energetic efficiency, modelling, transport, sustainability
Online: 28 June 2018 (15:30:59 CEST)
Based on rapeseed plantation biodiesel production system requires transportation of goods, like raw materials, machines and tools, and products between various conversion stages of agricultural as well as industrial subsystems. Each transportation step requires consumption of some energy. This consumption, decreases the net amount of energy delivered out of the biofuel production system, and consequently decreases energetic efficiency of the system. The present work deals with computer modelling of the influence of energy consumed on those transport routes on the energetic efficiency of production system. The effects caused by variation of several parameters like fuel consumption and load capacity of transportation means, size of plantation, distribution and sizes of individual fields, distances between fields, as well as plantation yield, and finally the distance between plantation and the industrial facility are studied using the numerical model developed
REVIEW | doi:10.20944/preprints201704.0004.v1
Subject: Social Sciences, Political Science Keywords: Sustainable transport, policy implementation, governance, institutions
Online: 3 April 2017 (16:35:36 CEST)
There is a large potential for cost-effective solutions to reduce greenhouse gas emissions and to improve the sustainability of the transport sector that is yet unexploited, in particular in the urban context. Considering the cost-effectiveness and the potential for co-benefits, it is hard to understand why energy gains and mitigation action in the transport sector is still lagging behind the potential. Particularly interesting is the fact that there is substantial difference among countries with relatively similar economic performances, such as the OECD countries in the development of their transport CO2 emission over the past thirty years despite the fact that these countries had relatively similar access to efficient technologies and vehicles. This study aims to apply some well established political science theories on the particular example of climate change mitigation in the transport sector in order to identify some of the factors that could help explain the variations in success of policies and strategies in this sector. The analysis suggests that institutional arrangements that contribute to consensus building in the political process provide a high level of political and policy stability which is vital to long-term changes in energy end-use sectors that rely on long-term investments. However, there is no direct correlation between institutional structures, e.g. corporatism and success in reducing greenhouse gas emissions in the transport sector. Environmental objectives need to be built into the consensus-based policy structure before actual policy progress can be observed. This usually takes longer in consensus democracies than in politically more agile majoritarian policy environments, but the policy stability that builds on corporatist institutional structures is likely to experience changes over a longer-term, in this case to a shift towards low-carbon transport that endures.
ARTICLE | doi:10.20944/preprints202109.0218.v1
Subject: Life Sciences, Other Keywords: cut flower; holding solution; pretreatment; transport; sucrose
Online: 13 September 2021 (15:39:57 CEST)
Vase life is one of the most important factors that determine the marketability of cut flowers and is greatly affected by the water balance. In recent years, cut hydrangea flowers are increasingly consumed as decorations for various events. However, the vase life of cut hydrangea flowers varies greatly depending on the postharvest solution management. Therefore, this study investigated the vase life, solution uptake, water balance, and relative fresh weight of freshly harvested hydrangea (Hydrangea macrophylla ‘Verena’) according to the three types of holding solutions (tap water, 1% chrysal professional Ⅲ (CPⅢ), 2% sucrose + 250 mg/L 8-hydroxquinoline + 100 mg/L citric acid (SHQC)) and the combination solutions (pretreatment; tap water, 0.1% chrysal RVB (RVB), floralife quickdip (FQ), transport; tap water, CPⅢ, floralife clear (FC), preservatives; CPⅢ, FC) for each distribution stage (pretreatment-transport-consumer). In the preservative comparison experiment, compared with the control, CPⅢ treatment and SHQC treatment significantly increased the vase life in 2019 (0.7 days, 3.4 days) and 2020 (1.4 days, 3.1 days), respectively. In the comparative experiment by solution combination, the group (RVB, FQ) using the pretreatment significantly extended the vase life by 4.6 days and 5.9 days compared to the tap water treatment. It was also determined that the same treatment increased overall solution uptake, maintained water balance longer, and increased relative fresh weight. These results confirm the importance of holding solutions and pretreatments, suggesting that appropriate pretreatments and preservatives should be used to improve the marketability of cut hydrangea flowers.
ARTICLE | doi:10.20944/preprints202103.0525.v1
Subject: Engineering, Control & Systems Engineering Keywords: Wildlife Monitoring; Multi-UAV System; Optimal Transport
Online: 22 March 2021 (11:59:55 CET)
This paper addresses a wildlife monitoring problem using a team of UAVs for efficient monitoring of wildlife. The state-of-the-art technology using UAVs has been an increasingly popular tool to monitor wildlife compared to the traditional methods such as satellite imagery-based sensing or GPS trackers. However, there still exist unsolved problems as to how the UAVs need to cover a spacious domain to detect animals as many as possible. In this paper, we propose the optimal transport-based wildlife monitoring strategy for a multi-UAV system, to prioritize monitoring areas while incorporating complementary information such as GPS trackers and satellite-based sensing. Through the proposed scheme, the UAVs can explore the large-size domain effectively and collaboratively with a given priority. The time-varying nature of wildlife due to their movements is modeled as a stochastic process, which is included in the proposed work to reflect the spatio-temporal evolution of their position estimation. In this way, the proposed monitoring plan can lead to efficient wildlife monitoring with a high detection rate. Various simulation results including statistical data are provided to validate the proposed work.
ARTICLE | doi:10.20944/preprints202012.0342.v1
Subject: Social Sciences, Accounting Keywords: supply chain management; transport; sustainability; quality; innovation
Online: 14 December 2020 (14:03:54 CET)
The present article proposes a complete framework for Supply Chain Strategy (SCS) analysis that is adapted to the specific characteristics of the agrifood chain, thereby facilitating management of the former. As a specific case of analysis, the horticultural supply chain, originating in Spain and ending with the European consumer, is analyzed, taking as a reference the marketing companies at origin (mainly social economy companies, i.e.; cooperatives). In addition, a survey of marketing companies is conducted to possibly determine which explicit cooperative growth strategies may include horizontal and vertical collaboration relationships with other members of the chain. The aim is to analyze with whom the cooperative collaborates within the supply chain and the key points of such collaboration. A model analyzing the influence of collaboration on company performance is also considered. The results reveal that, in recent years, aspects related to quality and health have been surpassed and replaced by the concept of sustainability within a framework of collaboration with customers. In any case, it becomes evident that there is a need to expand collaboration within the chain by incorporating the supplier of the supplier, with the aim of making the chain more profitable.
REVIEW | doi:10.20944/preprints201904.0023.v1
Online: 1 April 2019 (13:58:08 CEST)
Legumes are important sources of nitrogen and, therefore, the nitrogen fixing ability of the legume-rhizobia symbiosis has great potential to improve crop yields or reduce nitrogen fertilizer use. Unfortunately, legumes face serious and increasing threats of both biotic and abiotic stresses among which Fe-deficiency has been increased from past years. Fe nutrient deficiency limits pulse production and nitrogen fixation by specifically affecting any one of the four phases of legume-rhizobium symbiosis. Although Fe in soil is often present in adequate quantities, it is mainly present in insoluble Fe-(III) precipitates, limiting its uptake and utilization. The present review has focused on the iron nutrition and deficiency and probable uptake, transport and metabolism in legumes.
Subject: Materials Science, Nanotechnology Keywords: Anomalous; correlations; trans-PA; electronic transport; FET
Online: 27 March 2019 (08:41:38 CET)
The electronic transport stability in nanodevices composed by metal/trans-polyacetylene /metal with different long length has contributed greatly for performance, homogeneity, stability, organization of the chains, reproducibility and higher conductivity. In this paper, we present an analytical study of the electronic transport characteristics from dimerized trans-polyacetylene (trans-PA) molecules containing an odd-even number of sites coupled to metal leads (left and right) in T-shaped geometry using the extended Su-Schrieffer-Heeger (SSH) model based on tight-binding Hamiltonian with the Non-Equilibrium Green´s Function (NEGF) via Heisenberg´s equation of motion and the Keldysh´s formalism. Due to the complexity of the T-shaped odd-even chain, our proposal was to test the effects on the finite-length network for three, four, five sites and furthermore foresee for 17-sites. We show how to tune dimerization strength () coupling to the parameters and T-shaped geometry of the device to which it affects the overlap integral localized at the three endpoints of the T-shaped system, making both the odd and even chains to undergo a metal-insulator transition in their electronic behavior. The results reached through control parity of the chain plane of the parameters governing () the electronic and experimental tunneling allow a better understanding of the subject.
ARTICLE | doi:10.20944/preprints201806.0013.v1
Subject: Social Sciences, Econometrics & Statistics Keywords: sustainability; trust; distress; transport services; road freight transport; modal shift potential; shift paradigm; modelling; prediction; General Discriminant Analysis
Online: 1 June 2018 (10:44:39 CEST)
Confidence in intermodal transport has not yet been defined. There are many different approaches to the concept of trust. However, the authors embedded them in the light of the challenges of sustainability, linking with the shift paradigm. The objective of the article is to indicate the directions and criteria for the implementation of the shift paradigm, inscribed in the idea of sustainable transport. The auxiliary objective is to predict which countries in a given year will have the TRUST status, i.e. implement the shift paradigm, and which will not implement it (DISTRESS). The article uses taxonometric techniques and built a model using General Discriminant Analysis. On their basis, the utility function was approximated, including the directions of implementation of the shift paradigm depending on the scale of the environmental load of transport. In the course of the research, an original and innovative econometric model was constructed, pointing to three variables, which had the greatest impact on trust. Thanks to the cognitive value of the model, it is possible to identify individuals who deserve the trust, i.e. it will implement the shift paradigm, with 93% probability. In the future, it is worth expanding the research by models for each country.
REVIEW | doi:10.20944/preprints202208.0205.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: Cholesterol efflux; flavonoids; HDL; quercetin; reverse cholesterol transport
Online: 11 August 2022 (03:33:47 CEST)
One of the mechanisms used in the management and cure of atherosclerosis is reverse cholesterol transfer (RCT), which plays a vital role in the export of cholesterol from peripheral cells. Cholesterol efflux from macrophages in the subintima of the vessel wall is a critical part of RCT. ATP-binding cassette transporter A1 (ABCA1) and ATP-binding cassette transporter G1 (ABCG1) are involved in the transfer of cholesterol from arterial macrophages to extracellular high-density lipoprotein cholesterol (HDL). The HDL then transports esterified cholesterol to the liver for elimination. An important factor in the reverse cholesterol transport and excretion of extracellular cholesterol is HDL. Atherogenesis can be prevented by altering the processes of RCT and cholesterol efflux, and this might lead to novel treatment options for cardiovascular disease. Research of novel modifying variables for RCT and cholesterol efflux is necessary. A better understanding of RCT's molecular processes has been gained via research, allowing for the creation of new treatments that make use of RCT's potential for pharmacological improvement. The purpose of this review is to provoke discussion on the potential impact of selected flavonoids on cholesterol efflux on the progression of atherosclerosis (Fig. 1.).
ARTICLE | doi:10.20944/preprints202106.0138.v1
Online: 4 June 2021 (11:23:18 CEST)
The link between ICTs, freight transport, and CO2 emissions has not received much explicit examination by researchers, despite freight transportation being an egregious contributor to environmental degradation. This paper investigates how ICTs can affect environmental quality when interacting with freight transport activities in 43 countries over the period 2002-2014, using carbon emissions as a proxy for environmental damages. ICTs are measured in terms of internet, telephone, and mobile phone technologies. Using GMM methodology, the results show that ICTs contribute to dampening environmental degradation when interacting with freight transport activities. Specifically, a 10% increase in the interaction between ICTs and freight transportation will decrease carbon emissions by between 1.27% and 3.02%. The results further suggest that fixed and smartphone technologies are the main contributors to reducing emissions when adopted in some specific transport sectors (i.e. road, rail, and inland), while the internet is the most efficient technology when interacting with air transport activity. In addition, the interaction between ICTs and multimodality accelerates environmental quality. The policy implications of these findings are discussed.
ARTICLE | doi:10.20944/preprints202012.0531.v1
Subject: Earth Sciences, Atmospheric Science Keywords: River mouth; Rupat Strait; sediment transport; tidal current
Online: 21 December 2020 (14:32:15 CET)
The Rupat Strait, a part of the Malacca Strait, is recognized as semi-closed waters and shows a high activity; thus, discovering the transport sediment mechanism of the strait as a consequence of ambient and anthropogenic forces is essential. Hydrodynamic and sediment transport modelling was constructed using the 2-Dimensional Explicit method which is averaged over depth. The results show that the dispersion of sediment at high tide is longer than that at low tide. This follows the hydrodynamic model in which current velocity at high tide is greater than the ocean current at the low tide. The previous sediment observation supports the results of transport sediment modelling, indicating that the anthropogenic factors are highly associated with the sedimentation in the Rupat strait
ARTICLE | doi:10.20944/preprints202009.0648.v1
Subject: Life Sciences, Biochemistry Keywords: sustainable development; systemic sustainable transport development; systemic development
Online: 26 September 2020 (16:23:05 CEST)
The concept of sustainability and sustainable development, especially systemic sustainable development, still raises controversy in literature. The article makes an attempt to re-examine these concepts from a systems perspective, seeking foundations and applications in the selected sector. It is becoming increasingly clear that sustainability and sustainable development are aimed at integrated economic, social, cultural, political, and ecological factors [1[, (pp.641-642). This causes that the constructive approach to the issue is required, taking into account all the actors, areas and dimensions involved in the pursuit of systemic sustainable development. As a result, both local and global dimensions and the way they interact must be explored in a multi-faceted manner in order to offer a perspective more useful than other analytical approaches, because the systems view is a way of thinking in terms of connectedness, relationships, and context . The article aims to review selected publications and studies so as to form the general idea of systemic sustainable development and define the systemic development of sustainable transport, including in particular the perspective of the actors of the sector, transport providers (passenger, urban) and transport development program, implemented both by local governments and on the European scale. An attempt was made to identify elements of the systemic sustainable development model, setting it in the reality of the following subcategories: “Society”, “Economy” and “Environment” in sectoral terms. It is supposed that, systemic sustainable development is a conglomerate of public administration entities, companies operating in the sector, individual and corporate customers, acting in certain conditions for economic, social and environmental well-being, and a number of their initiatives of major or minor significance, grouped in six sub-areas, undertaken to achieve systemic value in the examined sector, with a positive or negative business/economic, social and environmental impact.
ARTICLE | doi:10.20944/preprints201903.0068.v2
Subject: Chemistry, Chemical Engineering Keywords: germanium; supported liquid membrane; transport; Cyanex 923; modeling
Online: 29 May 2019 (04:54:50 CEST)
A transport process was studied from an aqueous solution containing oxalic acid and 100 mg/L Ge using a flat sheet supported liquid membrane (FSSLM) system. Cyanex 923 immobilized in a polytetrafluoroethylene membrane was employed as a carrier. The solution chemistry and related diagrams were applied to study the transport of germanium. The effectual parameters such as oxalic acid, carrier concentration, and strip reagent composition were evaluated in this study. Based on the results, the oxalic acid concentration of 0.075 mol/L and the carrier concentration of 20 %v/v were the condition in which the efficient germanium transport occurred. Among strip reagents, NaOH (0.04-0.1 mol/L) had the best efficiency to transport germanium through the SLM system. Furthermore, the permeation model was obtained to calculate the mass transfer resistances of the membrane (Δm) and feed (Δf) phases. According to the results, the values of 1 and 1345 s/cm were evaluated for Δm and Δf, respectively.
ARTICLE | doi:10.20944/preprints201808.0552.v1
Subject: Materials Science, Nanotechnology Keywords: antiferromagnetism; spintronics; electronic transport; DFT; ab initio calculations
Online: 31 August 2018 (15:55:42 CEST)
We report the electronic, magnetic and transport properties of a prototypical antiferromagnetic (AFM) spintronic device. We chose Cr as the active layer because it is the only room-temperature AFM elemental metal. We sandwiched Cr between two non-magnetic metals (Pt or Au) with large spin-orbit coupling. We also inserted a buffer layer of insulating MgO to mimic the structure and finite resistivity of a real device. We found that, while spin-orbit has a negligible effect on the current flowing through the device, the MgO layer plays a crucial role. Its effect is to decouple the Cr magnetic moment from Pt (or Au) and to develop an overall spin magnetization. We have also calculated the spin-polarized ballistic conductance of the device within the Büttiker-Landauer framework, and we have found that for small applied bias our Pt/Cr/MgO/Pt device presents a spin polarization of the current amounting to ~25%.
ARTICLE | doi:10.20944/preprints201805.0054.v1
Subject: Social Sciences, Other Keywords: smart transport tools; ‘smart’ and sustainable; social-sustainability
Online: 3 May 2018 (08:17:38 CEST)
In the smart city, information and communications technologies (ICTs) are proposed as solutions to urban challenges, including sustainability concerns. While sustainability commonly refers to economic and environmental dimensions, the concept also contains a social component. Our study asked how smartphone applications (apps) address social sustainability challenges in urban transport, if at all. We focused on transport disadvantages experienced due to low income, physical disability, and language barriers. A review of 60 apps showed that transport apps respond to these equity and inclusion issues in two ways: (a) by employing universal design in general-use apps; including cost-conscious features; and providing language options (b) by specifically developing smartphone apps for persons with disabilities. The article discusses the study by positioning it in the literature of smart cities as well as socially sustainable transport.
ARTICLE | doi:10.20944/preprints201708.0020.v3
Subject: Earth Sciences, Atmospheric Science Keywords: Tropospheric ozone; pollution episode; satellite measurements; regional transport
Online: 4 October 2017 (11:23:38 CEST)
We use a regional scale photochemical transport model to investigate the surface concentrations and column integrated amounts of ozone (O3) and nitrogen dioxide (NO2) during a pollution event that occurred in the St. Louis metropolitan region in 2012. These trace gases will be two of the primary constituents that will be measured by TEMPO (Tropospheric Emissions: Monitoring of Pollution), an instrument on a geostationary platform, which will result in a dataset that has hourly temporal resolution during the daytime and ~4 km spatial resolution. Although air quality managers are most concerned with surface concentrations, satellite measurements provide a quantity that reflects a column amount, which may or may not be directly relatable to what is measured at the surface. Our model results provide reasonably good agreement with observed surface O3 concentrations (correlation coefficients ranging from 0.69 to 0.87 at each of the nine monitoring stations in the St. Louis region), which is the only trace gas dataset that can be used for verification. The model shows that a plume of O3 extends downwind from St. Louis and contains an integrated amount of ozone of ~ 16 Dobson Units (DU; 1 DU = 2.69 x 1016 molecules cm-2), an amount lower than what was observed during two massive pollution episodes in the 1980s. Based on the smaller isolatable emissions coming from St. Louis, this quantity is not unreasonable, but may also reflect the reduction of photochemical ozone production due to the implementation of emission controls that have gone into effect since the 1980s.
ARTICLE | doi:10.20944/preprints201705.0211.v1
Subject: Earth Sciences, Environmental Sciences Keywords: solute transport, dispersion, hagen-poiseuille flow, non-fickian
Online: 30 May 2017 (07:53:21 CEST)
We present an exact expression for the upscaled dynamic dispersion coefficient (D) for one-dimensional transport by Hagen-Poiseuille flow which is the basis for modeling transport in porous media idealized as capillary tubes. The theoretical model is validated by comparing the breakthrough curves (BTCs) from a 1D advection-dispersion model with dynamic D to that from direct numerical solutions utilizing a 2D advection-diffusion model. Both Taylor dispersion theory and our new theory are good predictors of D at lower Peclet Number (Pe) regime, but gradually fail to capture most parts of BTCs as Pe increases. However, our model generally predicts the mixing and spreading of solutes better than Taylor’s theory since it covers all transport regimes from molecular diffusion, through anomalous transport, and to Taylor dispersion. The model accurately predicts D based on the early part of BTCs even at relatively high Pe regime (~62) where the Taylor’s theory fails. Furthermore, the model allows for calculation of the time scale that separates Fickian from non-Fickian transport. Therefore, our model can readily be used to calculate dispersion through short tubes of arbitrary radii such as the pore throats in a pore network model.
ARTICLE | doi:10.20944/preprints201607.0066.v1
Subject: Earth Sciences, Geophysics Keywords: maximum flux; midlatitude cyclones; oceanic jets; chaotic transport
Online: 22 July 2016 (05:17:29 CEST)
Eddy-driven jets are of importance in the ocean and atmosphere, and to a first approximation are governed by Rossby wave dynamics. This study addresses the time-dependent flux of fluid and potential vorticity between such a jet and an adjacent eddy, with specific regard to determining zonal and meridional wavenumber dependence. The flux amplitude in wavenumber space is obtained, which is easily computable for a given jet geometry, speed and latitude, and which provides instant information on the wavenumbers of the Rossby waves which maximize the flux. This new tool enables the quick determination of which modes are most influential in imparting fluid exchange, which in the long term will homogenize the potential vorticity between the eddy and the jet. The results are validated by computing backward- and forward-time finite-time Lyapunov exponent fields, and also stable and unstable manifolds; the intermingling of these entities defines the region of chaotic transport between the eddy and the jet. The relationship of all of these to the time-varying transport flux between the eddy and the jet is carefully elucidated. The flux quantification presented here works for general time-dependence, whether or not lobes (intersection regions between stable and unstable manifolds) are present in the mixing region, and is therefore also easily computable for wave packets consisting of infinitely many wavenumbers.
ARTICLE | doi:10.20944/preprints202210.0249.v1
Subject: Engineering, Energy & Fuel Technology Keywords: IGCC; Ion Transport Membrane; air separator; integration; gasifier; HRSG
Online: 18 October 2022 (05:12:02 CEST)
Ion Transport Membrane (ITM) is a well-developed technology for producing O2 by separating air in its membrane. To decrease energy loss in air separation unit and to increase the overall efficiency of a power generation unit ITM is added with the gasification unit in this model. Ceramic materials are generally used to make ion transport membrane that produces oxygen by conducting oxygen ions at specified temperature. Potential advantages can be gained by integrating ITM technology with power generation units as 99% pure oxygen is produced from ITM. A salient comparison between ITM air separator combined with IGCC and cryogenic air separator combined with IGCC is done in this paper where the total power generation cycle remains same for both cases excluding the air separation units (ITM and cryogenic). Using ITM air separator is more beneficial compared to cryogenic air separation as ITM technology helps to improve IGCC overall efficiency and also reduces plant auxiliaries than that of power generation systems integrated with cryogenic.
ARTICLE | doi:10.20944/preprints202110.0370.v1
Subject: Life Sciences, Other Keywords: photosynthesis; elevated CO2; Rubisco; electron transport; light; diurnal cycle
Online: 25 October 2021 (15:52:11 CEST)
The response of carbon fixation in C3 plants to elevated CO2 is relatively larger when photosynthesis is limited by carboxylation capacity (VC) than when limited by electron transport (J). Recent experiments under controlled, steady-state conditions have shown that photosynthesis at elevated CO2 may be limited by VC even at limiting PPFD. These experiments were designed to test whether this also occurs in dynamic field environments. Leaf gas exchange was recorded every 5 minutes using two identical instruments both attached to the same leaf. The CO2 concentration in one instrument was controlled at 400 mol mol-1 and one at 600 mol mol-1. Leaves were exposed to ambient sunlight outdoors, and cuvette air temperatures tracked ambient outside air temperature. The water content of air in the leaf cuvettes was kept close to that of the ambient air. These measurements were conducted on multiple, mostly clear days for each of three species, Glycine max, Lablab purpureus, and Hemerocallis fulva. The results indicated that in all species, photosynthesis was limited by VC rather than J at both ambient and elevated CO2 both at high midday PPFDs and also at limiting PPFDs in the early morning and late afternoon. During brief reductions in PPFD due to midday clouds, photosynthesis became limited by J, The net result of the apparent deactivation of Rubisco at low PPFD was that the relative stimulation of diurnal carbon fixation at elevated CO2 was larger than would be predicted when assuming limitation of photosynthesis by J at low PPFD.
ARTICLE | doi:10.20944/preprints202110.0313.v1
Subject: Chemistry, Applied Chemistry Keywords: membrane transport; Cyanex 923; iron(III); manganese (II); separation.
Online: 21 October 2021 (14:10:48 CEST)
The transport of iron(III) from Fe(III)-Mn(II)-HCl mixed solutions through a flat-sheet supported liquid membrane is investigated, being the carrier phase of Cyanex 923 (commercially available phosphine oxide extractant) dissolved in Solvesso 100 (commercially available diluent), as a function of hydrodynamic conditions, concentration of manganese and HCl in the feed phase, and carrier concentration in the membrane phase. A transport model is derived that describes the transport mechanism, consisting of diffusion through a feed aqueous diffusion layer, a fast interfacial chemical reaction, and diffusion of the Fe(III)-Cyanex 923 complex across the membrane phase. The membrane diffusional resistance (Δm) and feed diffusional resistance (Δf) are calculated from the model, and their values are 145 s/cm and 361 s/cm, respectively. It is apparent that the transport of iron(III) is mainly controlled by diffusion through the aqueous feed boundary layer, being the thickness of this layer calculated as 2.9x10-3 cm. Since Mn(II) is not transported through the membrane phase, the present system allows to the purification of this manganese-bearing solutions.
REVIEW | doi:10.20944/preprints202106.0657.v1
Subject: Biology, Anatomy & Morphology Keywords: mitochondria, dynamics, transport, mitophagy, cell proliferation, stemness, fate acquisition
Online: 28 June 2021 (13:55:59 CEST)
Mitochondria are essential to cell homeostasis, and alterations in mitochondrial distribution, segregation or turnover have been linked to complex pathologies such as neurodegenerative diseases or cancer. Understanding how these functions are coordinated in specific cell types is a major challenge to discover how mitochondria globally shape cell functionality. In this review, we will first describe how mitochondrial transport and dynamics are regulated throughout the cell cycle in yeast and in mammals. Second, we will explore the functional consequences of mitochondrial transport and partitioning on cell proliferation, fate acquisition, stemness, and on the way cells adapt their metabolism. Last, we will focus on how mitochondrial clearance programs represent a further layer of complexity for cell differentiation, or in the maintenance of stemness. Defining how mitochondrial transport, dynamics and clearance are mutually orchestrated in specific cell types may help our understanding of how cells can transition from a physiological to a pathological state.
ARTICLE | doi:10.20944/preprints202105.0353.v1
Subject: Engineering, Automotive Engineering Keywords: Tortuosity; Microscale-Macroscale; Averaging; Equivalent Pore; Ion Transport; Concrete
Online: 14 May 2021 (16:17:16 CEST)
In this work, the transport equations of ionic species in concrete are studied. First, the equations at the porescale are considered, which are then averaged over a representative elementary volume. The so obtained transport equations at the macroscopic scale are thoroughly examined and each term is interpreted. Furthermore, it is shown that the tortuosity-connectivity does not slow the average speed of the ionic species down. The transport equations in the representative elementary volume are then compared with the equations obtained in an equivalent pore. Lastly, comparing Darcy’s law and the Hagen-Poiseuille equation in a cylindrical equivalent pore, the tortuosity-connectivity parameter is obtained for four dierent concretes. The proposed model provides very good results when compared with the experimentally obtained chloride profiles for two additional concretes.
ARTICLE | doi:10.20944/preprints202103.0683.v1
Subject: Engineering, Automotive Engineering Keywords: bike sharing; public transport; cycling; user analysis; impact analysis
Online: 29 March 2021 (11:26:12 CEST)
We report the experiences of the bike sharing system in Ningbo, China. To analyze the impact of the system, system log data are collected for the whole month of May 2014 (with more than 1.7 million usage records), supplemented by questionnaire data from 1,856 respondents. Our results show that public bike usage follows the same pattern as road traffic, with morning and evening peaks on week days. In terms of mode substitution, 16% of public bike trips would have been made by private cars. In average, each public bike is used 3.7 times per day, with each trip lasting around 23 minutes and covering around 3.5 kilometre. This translates into a reduction of car travel by more than 11 million kilometre per year, a significant contribution to the sustainability of urban transport in Ningbo.
ARTICLE | doi:10.20944/preprints202102.0427.v1
Subject: Materials Science, Biomaterials Keywords: molecular dynamics; diffusion; mass transport of water; polymer matrix
Online: 19 February 2021 (09:50:39 CET)
The diffusion process of water molecules within a polyetherimide (PEI) glassy matrix has been analyzed by combining the experimental analysis of water sorption kinetics performed by FTIR spectroscopy with theoretical information gathered from Molecular Dynamics simulations and with the expression of water chemical potential provided by a non-equilibrium lattice fluid model able to describe the thermodynamics of glassy polymers. This approach allowed to construct a convincing description of the diffusion mechanism of water in PEI providing molecular details of the process related to the effects of the cross- and self-hydrogen bondings established in the system on the dynamics of water mass transport.
ARTICLE | doi:10.20944/preprints202101.0029.v1
Subject: Social Sciences, Accounting Keywords: electric mobility; paratransit; informality; Sustainability transitions; East-Africa; transport
Online: 4 January 2021 (12:23:46 CET)
Electric mobility begins to enter East-African markets. This paper aims to investigate what policy level solutions and stakeholder constellations are established in the context of e-mobility in Dar es Salaam, Kigali, Kisumu and Nairobi and in which ways they attempt to tackle implementation of electric mobility solutions. The study employs two key methods including content analysis of policy and programmatic documents as well as interviews based on purposive sampling ap-proach with stakeholders involved in mobility transitions. The study findings point out that transport operators and their representative associations are less recognized as major players in the transition, far behind new e-mobility players (start-ups) and public authorities. The study further indicates that a set of financial and technical barriers persist such as high upfront invest-ment costs in vehicles and infrastructure, or anxieties regarding competitiveness with fossil fuel vehicles, that constrain the uptake of such private e-mobility initiatives. This study concludes by identifying current gaps that need to be tackled by policy makers and stakeholders in order to implement inclusive electric mobility in East-African cities, considering modalities that include transport providers and address their financial constraints.
ARTICLE | doi:10.20944/preprints202011.0432.v1
Subject: Engineering, Marine Engineering Keywords: Stratified Wakes; Turbulence; RANS; Secont-Moment Closure; Stress-transport
Online: 16 November 2020 (15:40:25 CET)
The problem of simulating wakes in a stratified oceanic environment with active background turbulence is considered. Anisotropic RANS turbulence models are tested against laboratory and eddy-resolving models of the problem. An important aspect of our work is to acknowledge that the environment is not quiescent; therefore, additional sources are included in the models to provide a non-zero background turbulence. The RANS models are found to reproduce some key features from the eddy-resolving and laboratory descriptions of the problem. Tests using the freestream sources show the intuitive result that background turbulence causes more rapid wake growth and decay.
ARTICLE | doi:10.20944/preprints202008.0237.v1
Subject: Engineering, Control & Systems Engineering Keywords: Intelligent transport systems; SCOOT; traffic control; traffic light; UOCT
Online: 10 August 2020 (05:35:19 CEST)
Today, transit control systems go beyond simple controllers located at the intersections of our streets, involving large companies in the field, which with the implementation and use of sophisticated equipment encompass endless new and advanced technologies that manage to give control to the massive automotive park, thus ensuring fluidity and road safety. Many of these systems are used in the big world capitals, which is why the model used in Santiago, Chile is a system applied and brought directly by the SIEMENS Company of England (specifically the system used in the City of London). It is capable of transmitting the different control signals in a similar and digital way from the different interconnected devices in and out of the road infrastructure.
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: adenosine receptor; nucleoside transport; CNS; inflammation; cardiovascular system; pain
Online: 9 April 2020 (16:19:14 CEST)
Many ligands directly target adenosine receptors (ARs). Here we review the effects of noncanonical AR drugs on adenosinergic signaling. Non-AR mechanisms include raising adenosine levels by inhibiting adenosine transport (e.g. ticagrelor, ethanol, cannabidiol), affecting intracellular metabolic pathways (e.g. methotrexate, nicotinamide riboside, salicylate, 5‐aminoimidazole‐4‐carboxamide riboside), or undetermined means (e.g. acupuncture). Yet other compounds bind ARs in addition to their canonical ‘on-target’ activity (e.g. mefloquine). The strength of experimental support for an adenosine-related role in a drug’s effects varies widely. AR knockout mice are the ‘gold standard’ method for investigating an AR role, but few drugs have been tested in these mice. Given the interest in AR modulation for treatment of cancer, CNS, immune, metabolic, cardiovascular, and musculoskeletal conditions, it is informative to consider AR and non-AR adenosinergic effects of approved drugs and conventional treatments.
ARTICLE | doi:10.20944/preprints201911.0332.v1
Subject: Chemistry, Applied Chemistry Keywords: indium(III); ionic liquid; liquid membranes; Hostarex A324; transport
Online: 27 November 2019 (05:04:40 CET)
The transport of indium(III), from HCl solutions, across a supported liquid membrane in flat-sheet configuration was investigated, being the carrier the ionic liquid HA324H+Cl- (derived from the tertiary amine Hostarex A324 and hydrochloric acid). Different variables affecting the metal transport: hydrodynamic conditions in the source and receiving phases, metal and HCl concentrations in the source phase, and carrier concentration in the membrane phase, were investigated. Also the transport of indium(III) using carriers of various nature: ionic liquids, alcohol, ketone, phosphine oxide, etc., was compared. The metal transport was modelled describing the transport mechanism as: diffusion across the source diffusion layer, a fast interfacial chemical reaction, and diffusion of the InCl4--carrier complex through the membrane support. Diffusional parameters for the transport of indium(III), from the experimental data and the model, were estimated.
ARTICLE | doi:10.20944/preprints201909.0219.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: aquaculture; computational biology; differential equation; ion transport; systems biology
Online: 19 September 2019 (05:03:11 CEST)
A mathematical expression to describe cation absorption of root is expressed with simulation results. The root cells selectively emit H+ ions with active transport consuming ATPs to establish electrical gradient. The gradient promotes external positive ions to flow into the roots, while carries negatively charged particles with symport. In this paper, a mathematical model whose independent variables are the concentrations of external and internal cation is presented. This differential equation is induced from Ohm’s law. The equation has terms for plant physiology, ion’s physical and electrical properties, growth of plant, and interaction between the root and the surroundings. Simulation showed that the physiology-related coefficient has important role on nutrition absorption.
ARTICLE | doi:10.20944/preprints201811.0427.v1
Subject: Materials Science, Polymers & Plastics Keywords: organic photovoltaics; charge transport; semi-empirical; kinetic Monte Carlo
Online: 19 November 2018 (07:09:55 CET)
Evaluating new, promising organic molecules to make next-generation organic optoelectronic devices necessitates the evaluation of charge carrier transport performance through the semi-conducting medium. In this work, we utilize quantum chemical calculations (QCC) and kinetic Monte Carlo (KMC) simulations to predict the zero-field hole mobilities of ~100 morphologies of the benchmark polymer poly(3-hexylthiophene), with varying simulation volume, structural order, and chain-length polydispersity. Morphologies with monodisperse chains were generated previously using an optimized molecular dynamics force-field and represent a spectrum of nanostructured order. We discover that a combined consideration of backbone clustering and system-wide disorder arising from side-chain conformations are correlated with hole mobility. Furthermore, we show that strongly interconnected thiophene backbones are required for efficient charge transport. This definitively shows the role "tie-chains" play in enabling mobile charges in P3HT. By marrying QCC and KMC over multiple length- and time-scales, we demonstrate that it is now possible to routinely probe the relationship between molecular nanostructure and device performance.
ARTICLE | doi:10.20944/preprints201801.0234.v1
Subject: Materials Science, General Materials Science Keywords: nanocrystalline ceramics; ionic transport; mechanochemsitry; NMR; conductivity spectroscopy; fluorides
Online: 25 January 2018 (04:46:39 CET)
Nanostructured materials have already become an integral part of our daily life. In many applications ion mobility decisively affects the performance of, e.g., batteries and sensors. Nanocrystalline ceramics often exhibit enhanced transport properties due to their heterogeneous structure showing crystalline (defect-rich) grains and disordered interfacial regions. In particular, anion conductivity in nonstructural binary fluorides easily exceeds that of their coarse-grained counterparts. To further increase ion dynamics aliovalent substitution is a practical method to influence the number of (i) defect sites and (ii) the charge carrier density. Here, we used high energy-ball milling to incorporate Y3+ ions into the cubic structure of SrF2. As compared to pure nanocrystalline SrF2 the ionic conductivity of Sr1-xYxF2+x with x = 0.3 increased by 4 orders of magnitude reaching 0.8 x 10 -5 S/cm-1 at 450 K. We discuss the effect of YF3 incorporation on conductivities isotherms determined by both activation energies and Arrhenius pre-factors. The enhancement seen is explained by size mismatch of the cations involved, which are forced to form a cubic crystal structure with extra F anions if x is kept smaller than 0.5
COMMUNICATION | doi:10.20944/preprints201705.0050.v1
Subject: Life Sciences, Molecular Biology Keywords: ABCC transporter; lateral roots; Triticum aestivum; auxin; transport inhibition
Online: 8 May 2017 (07:48:20 CEST)
TaABCC13 is member of wheat ABCC subclass of transporters. The RNAi mediated silencing of this transporter in wheat results in lowering of seed phytic acid level and other developmental defects. In addition to that, wheat ABCC13 was involved in cadmium detoxification as evident by the complementation assays in yeast. The appearance of early lateral roots in these transgenic seedlings speculated the possibility for studying the role of localized auxin-mediated effects. In the current study, firstly, the expression of auxin related genes was studied in the transgenic roots. Enhanced expression of genes pertaining to either auxin biosynthesis or its transport was observed in transgenic wheat seedling roots suggesting the direct effect of the hormone. Further, the early emergence of lateral roots in transgenic wheat seedlings was affected due to the presence of auxin-transport inhibitor suggesting the direct effect of hormones in root development. In conclusion, herein we provide the novel evidence for the auxin mediated regulation of lateral root emergence in TaABCC13:RNAi seedlings.
ARTICLE | doi:10.20944/preprints202212.0225.v1
Subject: Physical Sciences, Atomic & Molecular Physics Keywords: OLED; charge mobility; DFT; hopping transport; transfer integrals; reorganization energy
Online: 13 December 2022 (03:25:26 CET)
Luminophores featuring thermally activated delayed fluorescence (TADF luminophores) are the workhorse of the third- and fourth-generation OLEDs. While these compounds had usually been used as dopants embedded in the host, non-doped TADF OLEDs have recently shown significant progress as well reaching the performance comparable to the host-dopant ones. For efficient operation of the non-doped OLEDs, charge transport in neat films and single crystals of TADF luminophores is important; however, this issue was nearly unexplored theoretically. In the current study, we calculated charge mobilities in four TADF single crystals, which have different molecular packing motifs. Specifically, in one of them both donor and acceptor moieties form uniform π-stacks, while in the others donors (acceptors) show alternating lateral shifts along the stacks; the difference in molecular packing results in the difference of transfer integral between the molecules. Reorganization energies differ as well up to four times for the studied crystals. As a result, charge mobilities vary from 0.001 to ~0.3 cm2/(V∙s), the largest being predicted for the crystal of the luminophore consisting of rigid donor and acceptor. We anticipate that the results obtained can be useful for the design of TADF luminophores for non-doped OLEDs, OLETs and other organic light-emitting devices.
ARTICLE | doi:10.20944/preprints202211.0305.v1
Subject: Biology, Horticulture Keywords: ammonium transport; flowering Chinese cabbage; NH4+; NO3-; ion influx; overexpression
Online: 16 November 2022 (10:20:07 CET)
Nitrogen (N) is a major limiting factor for plant growth and vegetable production. Understanding the regulatory mechanisms of N uptake, transport, and assimilation is key to improving nitrogen use efficiency in plants. Ammonium transporters (AMTs) play an important role in plant N metabolism. In this study, we isolated an important AMT1 subfamily member (BcAMT1;5) with a highly conserved signatural AMT1 subfamily motif from flowering Chinese cabbage. Based on functional complementation in yeast mutant 31019b and overexpression of BcAMT1;5 in Arabidopsis, BcAMT1;5 is a functional ammonium transporter. Tissue expression analysis showed that BcAMT1;5 was mainly expressed in roots and showed multiple N regime transcript patterns to respond to varying nutritional conditions. This was up-regulated by N-deficiency and down-regulated by supplying NH4+. The glucuronidase (GUS) activities of BcAMT1;5pro::GUS showed a similar change in response to different N conditions. Overexpression of BcAMT1;5 accelerated the growth of transgenic seedlings, increased NH4+ net influxes, and enhanced the content and accumulation of NH4+ and NO3- at low N concentrations. Additionally, it increased the transcript levels of N assimilation-related genes in shoots. These results indicate that the transcriptional regulation of BcAMT1;5 in flowering Chinese cabbage may participate in N uptake and assimilation under various N conditions.
ARTICLE | doi:10.20944/preprints202211.0115.v1
Subject: Mathematics & Computer Science, General & Theoretical Computer Science Keywords: ECRIS; ion beam; extraction; ion beam transport; space-charge; simulation
Online: 7 November 2022 (10:06:02 CET)
A model for the simulation of ion beam extraction from an electron cyclotron resonance ion source is proposed. It is based on the simple fact that charged particles follow magnetic field lines. Therefore magnetic field lines are used to generate initial conditions for ray-tracing. This model reproduces in simulation experimentally obtained results. The importance of correlations in phase-space caused by the magnetic field is shown in simulation. This model also describes the physics of space-charge and its compensation in the extracted (fast) ion beam by low energy electrons. Simulation provides the possibility to test theoretical assumptions, as well as to optimize technical designs.
ARTICLE | doi:10.20944/preprints202203.0211.v1
Subject: Medicine & Pharmacology, Other Keywords: air pollution; microenvironment; public health; PM2.5; black carbon; active transport
Online: 15 March 2022 (11:34:12 CET)
The Particulate Matter (PM), particles of variable but small diameter could penetrate the respiratory system via inhalation, causing respiratory and/or cardiovascular diseases. This study aims to evaluate the association of environmental particulate matter (PM2.5) and black carbon (BC) with respiratory health and physical activity in users traveling by transportation modes over four roads in Bogotá. This was a mixed-method study, in 300 healthy participants, based on a convergent parallel design. Including a descriptive qualitative component focused on asserting the individual perception of air pollution by semi-structured interviews and a cross-sectional study measuring the individual exposure to PM2.5 and BC to evaluate the pulmonary function by spirometry. The analysis included concurrent triangulation and a Poisson regression. This study provides integration of air pollution exposure variables and respiratory health effects in different transport microenvironments. To our knowledge, this is the first mixed-methods study focused on PM2.5, BC, and respiratory health effects in a city above 2.000 meters above sea level.
ARTICLE | doi:10.20944/preprints202109.0298.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Arabian/Persian Gulf; Lagrangian model; pollutant transport; tide; baroclinic circulation
Online: 17 September 2021 (08:07:30 CEST)
A rapid-response Lagrangian model for simulating the transport of a chemical pollutant in the Arabian/Persian Guls is described. The model is well suited to provide a fast response after an emergency due to an accident or a deliberate spill. Baroclinic circulation was obtained from HYCOM ocean model and tides were calculated using a barotropic model. The interactions of pollutants with sediments (uptake/release processes) were described using a dynamic approach based on kinetic transfer coefficients and a stochastic numerical method. Some examples of model applications are shown.
ARTICLE | doi:10.20944/preprints202106.0195.v1
Subject: Materials Science, Nanotechnology Keywords: perovskite solar cells, electron transport layer, 2D perovskite, anti-solvent
Online: 7 June 2021 (16:15:59 CEST)
Surface passivation, which has been intensively studied recently, is essential for the perovskite solar cells (PSCs), due to the intrinsic defects in perovskite crystal. A series of chemical or physical methods have been published for passivating the defects of perovskite, which effectively suppressed the charge recombination and enhanced the photovoltaic performance. In this study, the n-type semiconductor of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) is dissolved in chlorobenzene (CB) for the surface passivation during the spin-coating process for depositing the two-dimensional (2D) perovskite film. This approach simplifies the fabrication process of 2D PSCs and benefits the film quality. As a result, the defects of perovskite film are effectively passivated by this method. A better perovskite/PCBM heterojunction is generated, exhibiting an increased film coverage and improved film morphology of PCBM. It is found that this technology results in an improved electron transporting performance as well as suppressed charge recombination for electron transport layer. As a result, PSCs based on the one-step formed perovskite/PCBM heterojunctions exhibit the optimized power conversion efficiency of 15.69% which is about 37% higher than that of regular perovskite devices. The device environmental stability is also enhanced due to the quality-improved electron transport layer.
ARTICLE | doi:10.20944/preprints202105.0159.v1
Subject: Physical Sciences, Acoustics Keywords: osmotic membrane; Polydimethylsiloxane; saline droplet; mass transport; evaporation; reversible cycle.
Online: 10 May 2021 (10:23:50 CEST)
We report cyclic growth/retraction phenomena observed for saline droplets placed on the cured PDMS membrane with the thickness of 7.8±0.1 µm floating on pure water surface. Osmotic mass transport across the micro-scaled floating PDMS membrane provided the growth of the sessile saline droplets followed by evaporation of the saline droplets. The observed growth/retraction cycle was reversible. The model of the osmotic mass transfer across the cured PDMS membrane is suggested. The model explains semi-quantitatively the time evolution of a droplet.
ARTICLE | doi:10.20944/preprints202104.0609.v1
Subject: Physical Sciences, Acoustics Keywords: nanoscale system; quantum transport; Coulomb blockade; entropy measurement; thermodynamic relations
Online: 22 April 2021 (13:29:10 CEST)
The entropy of a system gives a powerful insight into its microscopic degrees of freedom, however standard experimental ways of measuring entropy through heat capacity are hard to apply to nanoscale systems, as they require the measurement of increasingly small amounts of heat. Two alternative entropy measurement methods have been recently proposed for nanodevices: through charge balance measurements and transport properties. We describe a self-consistent thermodynamic framework for treating few-electron nanodevices which incorporates both existing entropy measurement methods, whilst highlighting several ongoing misconceptions. We show that both methods can be described as special cases of a more general relation and prove its applicability in systems with complex microscopic dynamics – those with many excited states of various degeneracies.
ARTICLE | doi:10.20944/preprints202012.0266.v2
Subject: Earth Sciences, Atmospheric Science Keywords: aviation; transport policy; climate change; pandemic; non-CO2; contrail-cirrus
Online: 8 March 2021 (16:23:27 CET)
This paper argues that, in 2020, the beneficial atmospheric effect from the reduction in aviation may have been at least 7-8 times greater than that occurring from the reduction in fossil carbon dioxide emissions from all sectors. Specifically, compared to potential atmospheric effects in 2020 without the pandemic, the decrease in effective radiative forcing from reduced contrail-cirrus formation may have been in the order of 35mWm-2 in 2020, compared to a reduction of only 4-5mWm-2 from the drop in fossil CO2 emissions. Over time, pursuing a low carbon pathway generates benefits that mount up to be much more significant than 2020 effects might imply, and is essential to stabilise the climate. However, a twin-track policy focus may be needed, with more emphasis on reducing short-term climate forcing, to minimise the impacts of climate change now, and to avoid detrimental feedback events. Future policy decisions about aviation should be made in this context.
ARTICLE | doi:10.20944/preprints202102.0198.v1
Subject: Engineering, Automotive Engineering Keywords: 180-degree bend; Sediment transport; Clear water; Open-channels; Scour
Online: 8 February 2021 (12:12:09 CET)
As 180-degree meanders are observed in abundance in nature, a meandering channel with two consecutive 180-degree bends was designed and constructed to investigate bed topography variations. These two 180-degree mild bends are located between two upstream and downstream straight paths. In this study, different mean velocity to critical velocity ratios have been tested at the upstream straight path to determine the meander's incipient motion. To this end, bed topography variations along the meander and the downstream straight path were addressed for different mean velocity to critical velocity ratios. In addition, the upstream bend's effect on the downstream bend has been investigated. Results indicated that the maximum scour depth at the downstream bend has increased as a result of changing the mean velocity to critical velocity ratio from 0.8 to 0.84, 0.86, 0.89, 0.92, 0.95, and 0.98 by respectively 1.5, 2.5, 5, 10, 12, and 26 times. Moreover, increasing the ratio increased the maximum sedimentary height by 3, 10, 23, 48, 49, and 56 times. The upstream bend's incipient motion was observed for the mean velocity to critical velocity ratio of 0.89, while the downstream bend was equal to 0.78.
ARTICLE | doi:10.20944/preprints202102.0095.v1
Subject: Mathematics & Computer Science, Algebra & Number Theory Keywords: COVID-19; Commute; Mobility practice; Low carbon travel; Transport sector
Online: 2 February 2021 (16:26:50 CET)
This chapter is written for the welfare of the society, questioning and enlightening the effects of the increment or decrement in the percentage of quality of air causing pollution due to the rise in the traffic post-lockdown due to COVID-19 in metro cities, specifically in Delhi. In this chapter, we address the question about people's preference in moving in the shared taxis to their workplaces or their reluctance and denial of the idea of moving in the shared vehicle because of the fear of getting infected. The sensitivity of the situation will compel the people to move in a single occupied vehicle (SOV). The rise in the number of vehicles on the roads will result in traffic jams and different kinds of pollution where people battling with the pandemic will inevitably get exposed to other health-related issues. We use a BPR (Bureau of Public Roads) model to combat this issue endangering the environment and public health. We exploit the BPR function to relate average travel time to the estimated number of commuters travelling by car. We collect mode share data from the NITI Ayog, the State Resource Centre and other authentic sources, which gives unique figures of the impact of shared mobility in India and how, in its absence, various sectors will get affected. Using the given data and the BPR, we evaluate increased vehicle volumes on the road if different portions of transit and carpool users switch to single-occupancy vehicles and its effect on multiple other factors. Based on the study of densely populated city, Delhi, we predict that cities with significant transit ridership are at risk for extreme traffic and pollution unless transit systems can resume safe with effective protocols.
ARTICLE | doi:10.20944/preprints202012.0175.v1
Subject: Life Sciences, Biochemistry Keywords: fruit transport; mechanical damage; physiological disorders; fruit maturity; colour; firmness
Online: 7 December 2020 (16:00:33 CET)
The study assessed the changes in the quality and physical and chemical parameters of apples of four cultivars (‘Gala’, ‘Idared’, ‘Topaz’, ‘Red Prince’) subjected to mechanical vibrations during transport under model conditions and after storage (shelf-life). Quality changes in apples were evaluated based on skin and flesh colour, total soluble solids, dry matter, firmness, titratable acidity, pH value, total polyphenol content and antioxidant capacity. The applied vibrations at a frequency of 28 Hz caused changes in the above parameters, which were visible also after storage and depended on cultivar, but did not show any clear trend or direction. Skin colour varied whereas flesh colour remained stable. Vibrations resulted in a decrease in firmness. The greatest stability of quality parameters, the highest content of bioactive compounds and the highest antioxidant capacity were observed for ‘Red Prince’ and ‘Topaz’ apples – this refers to the control and treated samples before and after storage. However, total polyphenol content and antioxidant capacity increased in all studied cultivars as a result of vibrations and storage, which suggests that 28 Hz mechanical vibrations and short-term cold storage did not reduce the health promoting potential of the apples.
ARTICLE | doi:10.20944/preprints202011.0371.v1
Subject: Chemistry, Analytical Chemistry Keywords: membrane transport; A327H+Cl- ionic liquid; gold; hydrochloric acid; nanoparticles.
Online: 13 November 2020 (10:57:44 CET)
By the use of the tertiary amine A327 and 1 M HCl solution as precursors, the ionic liquid A327H+Cl- was generated and used to investigate its performance in the transport of Au(III) form hydrochloric acid medium. The influence of the stirring speed (600-1800 min-1), ionic liquid concentration (1.25-50% v/v) in the membrane phase and gold concentration (0.01-0.15 g/L) in the feed phase on metal transport have been investigated. An equation which included both equilibrium and kinetics parameters was derived, and the membrane diffusional resistance (Δm) and feed phase diffusional resistance (Δf) was estimated as 9.5x106 s/cm and 307 s/cm, respectively. At carrier concentrations in the 5-50% v/v range and gold concentrations in the 0.01-0.15 g/L range, metal transport is controlled by diffusion of metal species through the feed boundary layer, whereas at the lowest carrier concentrations, membrane diffusion is predominant. From the receiving solutions, gold can be recovered as gold nanoparticles.
ARTICLE | doi:10.20944/preprints202009.0295.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Streamline-based simulation; Nanoparticle transport; Reservoir simulation; Field-scale simulation
Online: 13 September 2020 (16:03:33 CEST)
Nanoparticle (NP) transport is increasingly relevant to subsurface engineering applications such as aquifer characterization, fracture electromagnetic imaging and environmental remediation. An efficient field-scale simulation framework is critical for predicting NP performance and designing subsurface applications. In this work, for the first time, a streamline-based model is presented to simulate NP transport in field-scale subsurface systems. It considers a series of behaviors exhibited by engineered nanoparticles (NPs), including time-triggered encapsulation, retention, formation damage effects and variable nanofluid viscosity. The key methods employed by the algorithm are streamline-based simulation (SLS) and an operator-splitting (OS) technique for modeling NP transport. SLS has proven to be efficient for solving transport in large and heterogeneous systems, where the pressure and velocity fields are firstly solved on underlying grids using finite-difference (FD) methods. After tracing streamlines, one-dimensional (1D) NP transport is solved independently along each streamline. The adoption of OS enhances flexibility for the entire solution procedure by allowing different numerical schemes to solve different governing equations efficiently and accurately. For the NP transport model, an explicit FD scheme is used to solve the advection term, an implicit FD scheme is used for the diffusion term and an adaptive numerical integration is used to solve the retention terms. The model is implemented in an in-house streamline-based code, which is verified against analytical solutions, a commercial FD reservoir simulator (ECLIPSE) and an academic FD colloid transport code (MNMs). For a 1D homogeneous case, the effluent breakthrough curves (BTC) produced by the in-house simulator are in good agreement with the analytical solution and MNMs, respectively. For a two-dimensional (2D) heterogeneous case, the BTC and concentration pattern of the in-house simulator all match well with the solution produced by commercial simulator. Simulations on a synthetic three-dimensional (3D) nanocapsule application engineering design case, are performed to investigate the effect of fluid and NP properties on the displacement pattern of an existing subsurface fluid.
ARTICLE | doi:10.20944/preprints202007.0362.v1
Subject: Engineering, Civil Engineering Keywords: Maritime transport; Automatic mooring system; Container vessel; TEU; CO2 emissions.
Online: 16 July 2020 (13:45:05 CEST)
Taking into account the increase in the emission of greenhouse gases produced by ships, during navigation and maneuvering in the port, a direct consequence of the increase in maritime traffic, the international community has developed a broad set of regulations to limit such emissions. The installation in commercial ports of automatic mooring systems by means of vacuum suction cups (AMS), thus reducing considerably the time required to carry out the mooring and unmooring maneuvers of ships, is a factor that is considerably influencing the decrease in Emissions of polluting gases in commercial ports with high traffic. The objective of the present work is to verify the influence of the use of the AMS on the emissions of polluting gases produced in the facilities destined to the traffic of container ships. It examines the CO2 emissions of container ships that call in the only three container ports equipped with AMS: Salalah (Oman), Beirut (Lebanon) and Ngqura (South Africa). Between them, these three ports supported the transit of 6 million TEUS in 2017. The calculation of emissions is made taking into account the time saved when performing the mooring maneuvers using the new AMS system compared with when it is not used. To do this, two different calculation methods are used: EPA and ENTEC to then compare the results of the two and thus obtain the reduction in emissions per TEU in these terminals during the mooring maneuvers. The paper concludes with a discussion on the values of the reductions in emissions obtained and the advantages of the installation of AMS in commercial ports located near population centres.
ARTICLE | doi:10.20944/preprints202005.0184.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: covid-19 lockdown; mobility and transport; environmental data; smart city
Online: 11 May 2020 (03:24:26 CEST)
According to the changed operative conditions due to lockdown and successive reopening a number of facts can be analysed. The main effects have been detected on: mobility, environment, social media and people flows. While in this first report only mobility, transport and environment are reported. The analysis performed identified a strong reduction of the mobility and transport activities, and in the pollutants. The mobility reduction has been assessed to be quite coherent with respect to what has been described by Google Global mobility report. On the other hand, in this paper a number of additional aspects have been put in evidence providing detailed aspects on mobility and parking that allowed us to better analyze the impact of the reopening on an eventual revamping of the infection. To this end, the collected data from the field have been compared from those of google and some considerations with respect to the Imperial college Report 20 have been derived. For the pollutant aspects, a relevant reduction on most of them has been measured and rationales are reported.
ARTICLE | doi:10.20944/preprints202001.0262.v1
Subject: Materials Science, Metallurgy Keywords: indium(III); ionic liquid; supported, liquid membrane; Hostarex A324; transport
Online: 23 January 2020 (04:07:43 CET)
The transport of indium(III), from HCl solutions, across a supported liquid membrane in flat-sheet configuration was investigated, being the carrier the ionic liquid HA324H+Cl- (derived from the tertiary amine Hostarex A324 and hydrochloric acid). Different variables affecting the metal transport: hydrodynamic conditions in the source and receiving phases, metal and HCl concentrations in the source phase, and carrier concentration in the membrane phase, were investigated. Also the transport of indium(III) using carriers of various nature: ionic liquids, alcohol, ketone, phosphine oxide and phosphoric ester, was compared. The metal transport was modelled describing the transport mechanism as: diffusion across the source diffusion layer, a fast interfacial chemical reaction, and diffusion of the InCl4--carrier complex through the membrane support. Diffusional parameters for the transport of indium(III), from the experimental data and the model, were estimated.
ARTICLE | doi:10.20944/preprints201911.0125.v1
Subject: Earth Sciences, Atmospheric Science Keywords: tropical cyclone; Weather Research and Forecast model; zonal Ekman transport
Online: 12 November 2019 (09:32:21 CET)
We examine the role of zonal Ekman transport along the coast of Senegal on 30 August, 2015 when the tropical disturbance associated with Tropical Cyclone Fred was located to the west of Senegal causing considerable coastal damage to coastal areas south of Dakar, Senegal. Ten-meter winds from three Weather Research and Forecast model simulations were used to estimate zonal Ekman transport, with the largest values found during the 30 August. The simulations are in agreement with limited coastal observations showing increasing southerly wind speeds during 30 August but are overestimated relative to the 3 coastal stations. The strong meridional winds translate into increased zonal Ekman transport to the coast of Senegal on 30 August. The use of a coupled ocean model will improve the estimates of Ekman transport along the Guinea-Senegalese coast. The observed damage suggests that artificial and natural barriers (mangroves) should be strengthened to protect coastal communities in Senegal.
ARTICLE | doi:10.20944/preprints201904.0050.v3
Subject: Engineering, Civil Engineering Keywords: MPM Formula, Shield’s Number, Sediment Transport, Sediment Motion, Hydraulic Regime
Online: 9 April 2019 (12:31:43 CEST)
In this paper is discussed sediment transport as a mechanical process that characterises a natural stream or channel flow regime. The objective of experimental work presented in this paper is to recall and to give another prospect of well-known Meyer-Peter and Müller approach for estimation of Shield’s number (θ_c,θ) in laboratory conditions, and calibration of dimensionless MPM number (A). For this purpose two different experiments are conducted, during the first experiment water amount flushed on the flume and bed slope was changed simultaneously until equilibrium state is achieved, meanwhile is estimated the critical Shield’s number (θ_c). While, during the second experiment, water amount was kept constant, only bed slope of flume was continuously tilted, meanwhile sediment, discharge and Shield’s number (θ) was determined for given hydraulic conditions. In addition calibration of dimensionless MPM number (A) was performed, where several iteration were considered until for (A=3.42), sediment discharge measured become almost equal with sediment discharge computed by using MPM formula. After these experiments, is concluded that MPM formula can be used also for other certain initial condition and similar procedure may be adopted to calibrate the dimensionless MPM number (A) .
ARTICLE | doi:10.20944/preprints201811.0278.v1
Subject: Life Sciences, Molecular Biology Keywords: astrocytes; glutamine; SN1 (SNAT3); Sp1; protein kinase C; ammonia; transport
Online: 12 November 2018 (10:02:12 CET)
The involvement of astrocytic SN1 (SNAT3) transporter in ammonia-induced L-glutamine retention was recently documented in mouse cultured astrocytes. Here we investigated the involvement of specificity protein 1 (Sp1) transcription factor in SN1 regulation in ammonium chloride (“ammonia”)-treated astrocytes. Sp1 expression and its cellular localization were determined using real-time qPCR, Western blot and confocal microscopy, respectively. Sp1 binding to Snat3 promoter was analyzed by chromatin immunoprecipitation. Ammonia-induced Sp1 regulatory role in SN1-mediated [3H]glutamine transport was verified using siRNA and mithramycin A. The involvement of protein kinase C (PKC) isoforms in Sp1 level/phosphorylation status was verified using siRNA technology. Sp1 translocation to the nuclei and its enhanced binding to Snat3 promoter, along with Sp1 dependence of system N-mediated [3H]glutamine transport were observed in astrocytes upon ammonia exposure. Ammonia decreased the level of phosphorylated Sp1, and the effect was reinforced by long-term incubation with PKC modulator, phorbol 12-myristate 13-acetate, a treatment likely to dephosphorylate Sp1. Furthermore, silencing of PKCδ isoform abolished the increase of Sp1 level by ammonia. Collectively, the results demonstrate the regulatory role of Sp1 in regulation of SN1 expression and activity in ammonia-treated astrocytes and implicate altered Sp1 phosphorylation status in this capacity.
ARTICLE | doi:10.20944/preprints201810.0410.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Anion exchange, DOC, Dissolved phosphorus, Forest soil, Lysimeters, P transport
Online: 18 October 2018 (10:10:20 CEST)
Incidental P losses from non-point sources may contribute to eutrophication and to decreased soil fertility. These incidents have been related to heavy rainfall on freshly fertilized agricultural soils and little is known about such incidents on more natural soils or in forests. The aim of this work is to determine if incidents of high P leaching also occur in spruce forests, and if such incidents are of significance in P cycling. We found a peak in the mineral soil solution showing that single events of high P leaching occur. The orthophosphate concentration in the Bf-horizon of the 80-year old spruce forest peaked in the autumn of the second year of a continuous monitoring. The concentration increased by more than 85 times compared to the highest concentration obtained earlier during the sampling. The amount leached during this 6 months peak is 10 times higher than the average annual leaching. This P leaching might be due to a combination of high P deposition/through-fall and a high anion exchange with dissolved-organic-carbon and Cl-. We suggest that single events of high sub-surface P leaching may contribute to the overall P leaching, and might increase with the global warming as more DOC is expected to be released to the soil solution.
ARTICLE | doi:10.20944/preprints201810.0352.v1
Subject: Engineering, Marine Engineering Keywords: coastal erosion; beach renourishment; articulated concrete mat; piles; littoral transport
Online: 16 October 2018 (11:05:45 CEST)
This manuscript introduces prospective hard engineering solutions to continuous episodic erosional events on beaches utilized for recreation and tourism. The basis of this paper is information from a modeling study completed in 2011 on a two mile stretch of beach in South Carolina. The study utilized three alternative groin systems and a no groin option. The optimum spacing of the groin applications and the retention rate of a replenished beach at the location was determined based on running a computer model (Genesis) for the environmental conditions (wave climate, littoral transport, etc.) at the demonstration site. It was also determined that the innovative groin alternative presented in this paper would likely develop as the most effective cost/benefit relationship among the more conventional alternatives utilized in the United States. The experimental groin system (modular adjustable permeable groin(s) MAPG) was calculated to save initial construction costs by 25% to 30%as compared to the other alternatives. This was significant when considering that adjacent beach impacts are minimized and the beach berm is better protected over the typical beach re-nourishment cycle. This paper attempts to facilitate further discussion of regional sediment budget and (coastal zone) management by bridging the divide between choosing only sand nourishment vs. engineered structures. We demonstrate that reintroducing engineered structures in combination with beach nourishment can be a cost effective solution to episodic erosional events over time while allowing longshore sediment transport.
ARTICLE | doi:10.20944/preprints201802.0168.v1
Subject: Engineering, Mechanical Engineering Keywords: powder handling, flowability, dosing, transport, mixing, dispersion, piezoelectric actuators, vibrations
Online: 26 February 2018 (16:00:40 CET)
Since fine powders tend strongly to adhesion and agglomeration, their processing with conventional methods is difficult or impossible. Typically, in order to enable the handling of fine powders, chemicals are added to increase the flowability and reduce adhesion. This contribution shows that instead of additives also vibrations can be used to increase the flowability, to reduce adhesion and cohesion, and thus to enable or improve processes such as precision dosing, mixing, and transport of very fine powders. The methods for manipulating powder properties are described in detail and prototypes for experimental studies are presented. It is shown that the handling of fine powders can be improved by using low-frequency, high-frequency or a combination of low- and high-frequency vibration.
ARTICLE | doi:10.20944/preprints201710.0152.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Dust; High resolution; Particulate matter; Modeling; Air quality; Hemispheric transport
Online: 24 October 2017 (04:27:48 CEST)
Mineral dust is one of the most important aerosol in mass over the world, affecting health and dynamics. This aerosol is mainly emitted over arid areas but may be long-range transported, impacting the local budget of air quality in many cities. While models were extensively used to study a single specific event, or making a global analysis at coarse resolution, the goal of our study is to simultaneously focus on several areas - Europe, North America, Central Asia, East China and the Caribbean area - for a one month period, March 2014, avoiding any parameter fitting to better simulate a given dust outbreak. The simulation is performed for the first time with the hemispheric version of the CHIMERE model, with a horizontal resolution of 10km. In this study, an overview of several simultaneous dust outbreaks over the north hemisphere is proposed to assess the capability of such modelling tools to predict dust pollution events. A quantitative and qualitative evaluation of the most striking episodes is presented with comparisons to satellite data, ground based Particulate Matter and calcium measurements. Despite some overestimation of dust concentrations far from emission areas, the model is able to simulate the timing of the arrival of dust outbreaks on observational sites. For instance, several spectacular dust storms in the US and China are perfectly captured by the models. The high resolution allows to better describe and understand the orographic effects and the long-range transport of dust plumes.
ARTICLE | doi:10.20944/preprints202209.0038.v1
Subject: Earth Sciences, Oceanography Keywords: Coastal upwelling; Upwelling index; Scatterometer; Wind stress; Kelvin Wave; Ekman Transport
Online: 2 September 2022 (09:57:06 CEST)
Monsoon winds drive upwelling along the eastern coast of India during the south-west (SW) monsoons. These winds also provide alongshore windstress (AWS) resulting in positive cross-shore Ekman transport (ET) from March to the end of September. While instances of high ET and sea surface temperature based upwelling index (UI_SST) were observed along two parts of the coast: between Kashinagara and Kakinada in the north, and between Kavali and Point Calimere in the south. The UI_SST illustrated a much poorer agreement with local ET in the northern section, where the onset of UI_SST preceded the rise of ET and the subsidence of UI_SST signals occurred during a period of rising ET. Additionally, negative sea surface height anomalies (SSHAs), typically associated with coastal upwelling, were also missing through most of the upwelling period. A complex empirical orthogonal function (CEOF) analysis revealed two coherent modes of SSHA variation. The first mode showed a SSHA signature spatio-temporally coincident with the first upwelling and downwelling Kelvin waves closely associated with the equatorial zonal winds that drive them. The second CEOF mode, with a coastal SSHA pattern similar to the SSHA signatures of coastal upwelling, was associated with local offshore ET along the Indian east coast. The CEOF analysis exhibited the triggering of coastal upwelling in April and its suppression from June by coastally trapped Kelvin waves along the northeastern coast of India, while local AWS driven ET was the primary driver of coastal upwelling along the southeastern coast. The second CEOF mode also exhibited a coherent negative coastal SSHA signature excited by local AWS driven ET during the upwelling period. This study examined the spatio-temporal variability of premonsoon and SW monsoon coastal upwelling along the western Bay of Bengal and its relation to remotely forced coastal Kelvin waves.
ARTICLE | doi:10.20944/preprints202207.0061.v1
Subject: Earth Sciences, Oceanography Keywords: Coastal upwelling; Upwelling index; Scatterometer; Wind stress; Kelvin Wave; Ekman Transport
Online: 5 July 2022 (05:36:03 CEST)
Monsoon winds drive upwelling along the eastern coast of India during the south-west (SW) monsoons. These winds also provide alongshore windstress (AWS) resulting in positive cross-shore Ekman transport (ET) from late May to the end of September. While instances of high ET and sea surface temperature (SST) based upwelling index (UI_SST) were observed along different parts of the coast, UI_SST was weaker in the northern section in the earlier part of monsoon. This was even in the presence of maximum AWS and ET during the 10 years analysis period spanning January-2009 to December-2018. Additionally, negative sea surface height anomalies (SSHAs), typically associated with coastal upwelling, were observed only along the southern-most coast. An empirical orthogonal function (EOF) analysis revealed two coherent modes of SSHA variation. The first principal component (PC) showed a SSHA signature coincident spatio-temporally with the first downwelling Kelvin wave, closely associated with the equatorial zonal winds that drive coastal Kelvin waves. The third PC with a coastal SSHA pattern similar to the second upwelling Kelvin wave was associated with offshore ET along the northern part of the Indian east coast. Time series of the two PCs exhibited suppression of coastal upwelling by downwelling Kelvin waves during May-July along the northeastern coast of India. Local AWS driven ET was the primary driver of coastal upwelling with the weakening of the remotely forced Kelvin waves in August. A coherent mode consisting of negative coastal SSHA signature was excited in response to local AWS driven ET during the upwelling period. This study examined the spatio-temporal variability of SW monsoon coastal upwelling along the east coast of India and illustrated the role of equatorial windstress forced first downwelling Kelvin wave in suppressing upwelling in the northern part of the coast during early SW monsoon season.
ARTICLE | doi:10.20944/preprints202111.0016.v1
Subject: Engineering, Other Keywords: Road Traffic; Air Pollution Assessment; Emission factors; Statistical Approach; Transport Policy
Online: 1 November 2021 (12:51:36 CET)
In the article a statistical approach to the assessment of the emission rates discharged by the road traffic in a spatial context is proposed. It exploits an indicator, the Yearly Average Vehicle, representing the pollutant emission rate of the average vehicle belonging to a specific category, and considers the statistical variability of most of the involved traffic parameters: vehicle speed and mileage travelled in the considered time period. Finally, indicators, assessing both the most probable value among the possible emission rates and the extent of their variability range, are proposed. They may also be used to underpin decision making-processes, when the effects of different policies addressing air pollution issues, are to be evaluated. Therefore, they are suitable for the analysis supporting urban planning activities, with a view to addressing and mitigating the effects and the consequences of pollution due to the transportation sector of the urban context.
Subject: Engineering, Energy & Fuel Technology Keywords: Transport Corrected SP3; Nodal Expansion Method; Generalized Equivalence Theory; Discontinuity Factors
Online: 3 September 2021 (08:12:14 CEST)
The Simplified Spherical Harmonic (SPN) approximation was first introduced as a three-dimensional (3-D) extension of the plane-geometry Spherical Harmonic (PN) equations. A third order SPN (SP3) solver, recently implemented in the Nodal Expansion Method (NEM), has shown promising performance in the reactor core neutronics simulations. This work is focused on the development and implementation of the transport corrected interface and boundary conditions in NEM SP3 solver, following recent published work on the rigorous SPN theory for piecewise homogeneous regions. A streamlined procedure has been developed to generate the flux zero and second order/moment discontinuity factors (DFs) of the generalized equivalence theory to eliminate the error introduced by pin-wise homogenization. Moreover, several color set models with varying size and configuration are later explored for their capability of generating DFs that can produce results equivalent to that using the whole-core homogenization model for more practical implementations. The new developments are tested and demonstrated on the C5G7 benchmark. The results show that the transport corrected SP3 solver shows general improvements to power distribution prediction compared to the basic SP3 solver with no DFs or only zero order/moment DFs. The complete equivalent calculations using the DFs can almost reproduce transport solutions with high accuracy. The use of equivalent parameters from larger size color set models show better prediction in the whole-core calculations. By coupling different color set models DFs can offer the best accuracy at both eigenvalues and power distributions.
Subject: Keywords: membrane theory; Association-Induction Hypothesis; ion transport, ion adsorption; membrane potential
Online: 13 August 2021 (08:53:04 CEST)
Accurate prediction of the membrane potential by membrane theory is possible on the basis that the plasma membrane is selectively permeable to ions and that permeability determines the characteristics of the membrane potential. However, an experimental and artificial cell system with an impermeable membrane serving as a model plasma membrane has a non-zero membrane potential, and this potential generated across the membrane is somehow consistent with the potential characteristics predicted by the membrane theory, despite the impermeability of the membrane to ions. A long-forgotten theory, called the association-induction hypothesis (AIH), has emerged as a more plausible mechanism for generating the membrane potential than the membrane theory to explain this unexpected behavior. The AIH asserts that ion-selective membrane permeability is not necessary for the generation of the membrane potential, which is contrary to the membrane theory. Although such an idea is not easy to accept, the experimental results clearly suggest the correctness of the AIH.
ARTICLE | doi:10.20944/preprints202104.0718.v1
Subject: Materials Science, Nanotechnology Keywords: Thermal evaporation synthesis; Zn2SnO4/ZnO; heterostructured nanowire arrays; interface; charge transport
Online: 27 April 2021 (12:49:02 CEST)
Abstract The construction of a heterostructured nanowire array allows the manipulation of the interfacial, surface, charge transport, and transfer properties simultaneously, offering new opportunities to achieve multi-functionality for various applications. Herein, we developed a facile thermal evaporation and post-annealing method to synthesize ternary-Zn2SnO4/binary-ZnO radially heterostructured nanowire arrays (HNA). Vertically aligned ZnO nanowire arrays (3.5 μm in length) were grown on a ZnO-nanoparticle-seeded fluorine-doped tin oxide substrate by a hydrothermal method. Subsequently, the amorphous layer consisting of Zn-Sn-O complex was uniformly deposited on the surface of the ZnO nanowires via the thermal evaporation of the Zn and Sn powder mixture in vacuum, followed by post-annealing at 550 °C in air to oxidize and crystallize the Zn2SnO4 shell layer. The use of a powder mixture composed of elemental Zn and Sn (rather than oxides and carbon mixture) as an evaporation source ensures high vapor pressure at a low temperature (e.g., 700 °C) during thermal evaporation. The morphology, microstructure, and charge-transport properties of the Zn2SnO4/ZnO HNA were investigated by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and electrochemical impedance spectroscopy. Notably, the optimally synthesized Zn2SnO4/ZnO HNA shows an intimate interface, high surface roughness, and superior charge-separation and -transport properties compared with the pristine ZnO nanowire array.
ARTICLE | doi:10.20944/preprints202012.0574.v1
Subject: Physical Sciences, Fluids & Plasmas Keywords: magnetically confined plasma; impurity, charge state, transport, coronal equilibrium; diffusion coefficient
Online: 23 December 2020 (09:25:32 CET)
The general coupling between particle transport and ionization-recombination processes in hot plasma is considered on the key concept of equilibrium charge state (CS) transport. A theoretical interpretation of particle and CS transport is gained in terms of a two-dimensional (2D) Markovian stochastic (random) processes, a discrete 2D Fokker-Plank-Kolmogorov equation (in charge and space variables) and generalized 2D coronal equilibrium between atomic processes and particle transport. The basic tool for analysis of CS equilibrium and transport is the equilibrium cell (EC) (two states on charge and two on space), which presents (i) a unit phase volume, (ii) the characteristic scale of local equilibrium, (iii) a comprehensive solution for the simplest nonlinear relations between transport and atomic processes. The approach opens up new perspectives on transport studies: (i) the direct modelling of equilibrium and transport of impurity using the atomic data base, (ii) recovery of the complete recombination rate profile based on knowledge of density profiles and ionization rate profiles, (iii) the local transport analysis, based on the reduction of the equilibrium set to the single EC (in particular, central or edge), (iv) analysis of the reduced transport coefficients (diffusion and convection) on the density profile measurements.
ARTICLE | doi:10.20944/preprints202010.0157.v1
Subject: Earth Sciences, Atmospheric Science Keywords: PM2.5; biomass burning; long-range transport of PM2.5; Source of PM2.5
Online: 7 October 2020 (11:23:14 CEST)
This paper aims to investigate the airflow that can transport emission sources of PM2.5 from neighboring countries to contribute to air pollution in northern Thailand. We applied the coupled atmospheric and air pollution model which is based on the Weather Research and Forecasting Model (WRF) and a Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT). The model output was compared to the ground-based measurement from the Pollution Control Department (PCD) to examine model performance. As a result of model evaluation, the meteorological variables fairly agreed well compared to observation with Index of Agreement (IOA) in ranges of 0.57 to 0.79 for temperature and 0.32 to 0.54 for wind speed, while the fractional bias of temperature and wind speed were 1.3 to 2.5 °C and 1.2 to 2.1 m/s. Burma was a country that contributed much of hotpot locations by 37% of the entire hotspot locations of Southeast Asia in March. The influence of the Asian Monsoon can bring pollutants from neighboring countries such as Burma and Laos toward northern Thailand in March that likely contribute to high concentrations of PM2.5 in northern Thailand.
ARTICLE | doi:10.20944/preprints202009.0205.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: Franz-Bampa; BCS drugs; biomimetic membrane; Franz cell; passive drug transport
Online: 9 September 2020 (10:25:54 CEST)
A major parameter controlling the extent and rate of oral drug absorption is permeability through the lipid bilayer of intestinal epithelial cells. Here, a biomimetic artificial membrane permeability assay (Franz-Bampa) was validated using Franz cells apparatus. Both high and low permeability drugs (metoprolol and mannitol, respectively) were used as external standards. Biomimetic properties of Franz-Bampa were also characterized by electron paramagnetic resonance spectroscopy (EPR). Moreover, the permeation profile for the 14 BCS class I-IV drugs cited in the FDA guidance (including other drugs as acyclovir, cimetidine, diclofenac, ibuprofen, piroxicam, and trimethoprim) were measured across Franz-Bampa. Apparent permeability (Papp) was compared to literature fraction dose absorbed in humans (Fa%). Papp in Caco-2 cells and Corti artificial membrane were likewise compared to Fa% to assess Franz-Bampa performance. Mannitol and metoprolol Papp values across Franz-Bampa were lower (3.20 x 10-7 and 1.61 x 10-5 cm/s, respectively) than those obtained across non-impregnated membrane (2.27 x 10-5 and 2.55 x 10-5 cm/s, respectively), confirming lipidic barrier resistivity. Performance of the Franz cell permeation apparatus using an artificial membrane showed similar log linear correlation (R2 = 0.664) with Fa%, as seen for Papp in Caco-2 cells (R2 = 0.805). Data support the validation of the Franz-Bampa method for use during drug discovery process.
REVIEW | doi:10.20944/preprints202008.0457.v1
Subject: Life Sciences, Biochemistry Keywords: cardiovascular disease; hypertension; atherosclerosis; electroneutral transport; cation-chloride-cotransporters; KCCs; NKCCs
Online: 20 August 2020 (13:00:59 CEST)
The SLC12 family of cation-chloride-cotransporters (CCCs), comprising potassium chloride cotransporters (KCCs)-mediated Cl- extrusion relative to sodium chloride cotransporters (NKCCs)-mediated Cl- loading, play vital roles in cell volume regulation and ion homeostasis. These functions of the CCCs influence a variety of physiological processes, many of which overlap with the pathophysiology of cardiovascular disease. Although not all of the cotransporters have been linked to Mendelian genetic disorders, recent studies have provided new insights into their functional role in vascular and renal cells along with their contribution to cardiovascular diseases. Particularly, an imbalance in potassium levels promote the pathogenesis of atherosclerosis and disturbances in sodium homeostasis are one of the causes of hypertension. Recent findings even suggest hypothalamic signalling as a key signalling pathway in the pathophysiology of hypertension. In this review, we summarize and discuss the role of CCCs in cardiovascular disease with particular emphasis on knowledge gained in recent years on NKCCs and KCCs.
ARTICLE | doi:10.20944/preprints202005.0139.v1
Subject: Engineering, Civil Engineering Keywords: transport mode; revealed preference; stated preference; multinomial logit model; university students
Online: 8 May 2020 (08:42:54 CEST)
This work mainly aims to identify and understand the factors influencing the switching of transportation modes among higher-education students in Joinville, Brazil when traveling to universities. Furthermore, this study evaluates the possibility of switching from individual vehicles to other modes of transport (i.e., bus, bicycle, and walking) by employing a multinomial logit model. The results indicate that students would be interested in switching from individual motor vehicles to other options. The scenarios for switching to buses presented the highest switching probability. The bus cost was the most important factor for switching. Meanwhile, the parking space reduction does not affect the student's choice, indicating that restricting available spaces should not be an isolated measure for decreasing the car mode attractiveness. Finally, the transport mode switch would occur only if alternative modes to the car or their infrastructure are improved; otherwise, students maintain their usual choices.
COMMUNICATION | doi:10.20944/preprints201909.0313.v1
Subject: Life Sciences, Other Keywords: substrate-binding protein; sbp; abc transport; α/β-domain; rhodothermus arinus
Online: 27 September 2019 (12:16:07 CEST)
Substrate binding proteins (SBP) bind to specific ligands in the periplasmic region and bind to membrane proteins to participate in transport or signal transduction. Typical SBPs consist of two α/β domains and recognize the substrate by hinge motion between two domains. Conversely, short length Rhodothermus marinus SBP (named as RmSBP) exists around the methyl-accepting chemotaxis protein. We previously determined the crystal structure of RmSBP consisting of a single α/β domain, but the substrate recognition mechanism is still unclear. To better understand the short length RmSBP, we performed comparative structure analysis, computational substrate docking, and X-ray crystallographic study. RmSBP shares a high level of similarity in α/β domain with other SBP proteins, but it has a distinct topology in the C-term region. The substrate binding model suggested that conformational change in the peripheral region of RmSBP was required to recognize the substrate. We determined the crystal structures of RmSBP at pH 5.5, 6.0, and 7.5. RmSBP showed structural flexibility of the β1-α2 loop, β5-β6 loop, and extended C-term domain based on the electron density map and temperature B-factor analysis. These results provide information that will further the understanding of the function of the short length SBP.
ARTICLE | doi:10.20944/preprints201812.0269.v1
Subject: Social Sciences, Organizational Economics & Management Keywords: city logistics; environmental sustainability; social sustainability; urban bus transport; IPA; AHP
Online: 24 December 2018 (05:09:11 CET)
Logistics in urban areas are currently suffering a radical transformation due to increasingly population concentration and the massive use of cars as the preferred transport mode. These issues have resulted in higher pollution levels in urban environments and traffic congestion impacting the world globally. Facilitating the use of sustainable transport modes is widely regarded as a necessity to cope with these adverse effects on citizens’ life quality. Hence, some regions, as the European Union, are encouraging bus transport firms to make their business models more environmentally and socially sustainable. The aim of this research is thus to explore how practices adopted by urban bus companies can improve cities’ sustainability. With this in mind, a combined Importance Performance Analysis (IPA)-Analytic Hierarchy Process (AHP) method was applied. In this way, both environmental and social sustainability effects of developed practices were represented through hierarchical structures separately. Subsequently, importance and performance ratings of practices in each sustainability dimension were estimated, and thus two IPA grids were generated. These grids support managers in the establishment of more effective action plans to improve logistics sustainability in cities. Findings also provide guidance to governments on the practices that should be promoted in future urban mobility plans.
ARTICLE | doi:10.20944/preprints201809.0341.v1
Subject: Biology, Plant Sciences Keywords: Polar Auxin Transport; PIN transporters; Secretion; 3D-SIM microscopy; Mathematical modeling
Online: 18 September 2018 (10:09:24 CEST)
Intercellular transport of auxin is driven by PIN-formed (PIN) proteins. PINs are localized at the plasma membrane (PM) and on constitutively recycling endomembrane vesicles. Therefore, PINs can mediate auxin transport either by direct translocation across the PM or by pumping it into secretory vesicles (SVs), leading to its secretory release upon fusion with the PM. Which of these two mechanisms dominates is a matter of debate. Here we addressed the issue with a mathematical modeling approach. We demonstrate that the efficiency of secretory transport depends on SV size, half-life of PINs on the PM, pH, exocytosis frequency and PIN density. 3D-SIM microscopy was used to determine PIN density on the PM. Combing this data with published values of the other parameters, we show that the transport activity of PINs in SVs would have to be at least 1000x greater than on the PM in order to produce a comparable macroscopic auxin transport. If both transport mechanisms operated simultaneously and PINs were equally active on SVs and PM, the contribution of secretion to the total auxin flux would be negligible. In conclusion, while secretory vesicle-mediated transport of auxin is intriguing and theoretically possible model, it unlikely to be a major mechanism of auxin transport in planta.
ARTICLE | doi:10.20944/preprints201807.0385.v2
Subject: Social Sciences, Other Keywords: low carbon island; electric motorcycles; green transport; battery exchange; carbon emissions
Online: 5 September 2018 (16:23:53 CEST)
Global warming and climate change have led to extreme changes in climatic conditions in recent years. The Taiwan government designates the construction of the Kinmen County as low carbon islands, to promote the operation of 100 electric motorcycles and battery demonstration. This study combined with island tourism, after boarding the island, visitors can rent electric motorcycles from the passenger service center and coordinate with the island tour map to show the location of the battery exchange points, so as to facilitate the search. During the operation, the amount of electric motorcycle lease is 15,551 times, the total mileage of motor vehicle is 284,404 km, the number of battery exchange is 622 times, the lease income is about NT$900,000. To reduce carbon and economic benefits of the assessment, compared to the motorcycles (50 c.c), electric motorcycles (EM 100) can reduce the carbon emissions by 8,726 kg, reducing energy costs of NT$422,594.
REVIEW | doi:10.20944/preprints201809.0057.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: metal-insulator transitions; electronic transport in interface structures; quantum hall effects
Online: 4 September 2018 (06:03:44 CEST)
The apparent metal-insulator transition (MIT) in two-dimension (2D) was discovered by Kravchenko et al.  more than two decades ago in strongly interacting 2D electrons residing in a Si-metal-oxide-semiconductor field-effect transistor (Si-MOSFET). Its origin remains unresolved. Recently, low magnetic field reentrant insulating phases (RIPs), which dwell between the zero-field (B=0) metallic state and the integer quantum Hall (QH) states where the Landau-level filling factor υ > 1, have been observed in strongly correlated 2D GaAs hole systems with large interaction parameter rs (~20-40) and high purity. A new complex phase diagram was proposed, which includes zero field MIT, low magnetic field RIPs, integer QH states, fractional QH states, high field RIPs and insulating phases (HFIPs) with υ < 1 in which the insulating phases are explained by the formation of Wigner crystal. Furthermore, evidences of new intermediate phases were reported. All contribute to the further understandings of the puzzle. This review article serves the purpose of summarizing those recent experimental findings and theoretical endeavors, to foster future research efforts.
ARTICLE | doi:10.20944/preprints201807.0387.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: membrane fouling; membrane plasticization; nutrients transport properties; perfusion bioreactors; tissue engineering
Online: 20 July 2018 (14:01:37 CEST)
High porosity and mass transport properties of microfiltration polymeric membranes benefits nutrients supply to cells when used as scaffolds in interstitial perfusion bioreactors for tissue engineering. High nutrients transport is assumed when pore size and porosity of the membrane are in the micrometric range. The present work demonstrates that the study of membrane fouling by proteins present in the culture medium, though not done usually, should be included in the routine testing of new polymer membranes for this intended application. Two poly(ε-caprolactone) microfiltration membranes presenting similar average pore size (~0.7µm) and porosity (>80%) but different external surface porosity and pore size have been selected as case study. The present work demonstrates that a membrane with lower surface pore abundance and smaller external pore size (~0.67 µm), combined with adequate hydrodynamics and tangential flow filtration mode is usually more convenient to guarantee high flux of nutrients. On the contrary, having large external pore size (~1.70µm) and surface porosity would incur in important internal protein fouling that could not been prevented with the operation mode and hydrodynamics of the perfusion system. Additionally, the use of glycerol in the drying protocols of the membranes might cause plasticization and a consequent reduction of mass transport properties due to membrane compaction by the pressure exerted to force perfusion. Therefore, preferentially, drying protocols that omit the use of plasticizing agents are recommended.
ARTICLE | doi:10.20944/preprints201805.0400.v1
Subject: Engineering, Civil Engineering Keywords: illegal taxi; door to door service; local public transport; traffic congestion
Online: 28 May 2018 (11:05:42 CEST)
The impact of an unlicensed low-cost taxi in Bangladesh is very severe, especially in municipal cities. Day by day the numbers of unlicensed low-cost taxi are increasing by jumping up and creating pressure on traffic and transportation system. The aim of this study is to find out the causes of increasing illegal taxi and the extent of this vehicle in the municipalities of Bangladesh. Pabna municipality is used as a case study due to the more activeness of illegal taxi then the other municipalities. To achieve the objectives, the researcher used a qualitative approach to acquire more depth about the problems. Besides a direct observation of the study area, an open-ended questionnaire survey and HIS survey were conducted. The illegal low-cost taxi is very active it was analyzed through the field survey. A statistical model was developed to understand the actual causes of increasing illegal low-cost taxi, where ten predicted hypotheses (age, education level, marital status and family member support of illegal drivers, and the variable of commuter satisfaction e.g. safety, comfort, continuous service, affordability of service, reliability of service and driver behavior) were tested. The model was run through the multiple regression analyses technique in SPSS and the result proved that education level of illegal low-cost taxi drivers, and the commuter satisfaction variable (safety and comfort) had a positive and significant effect of increasing illegal low-cost taxi in the study area. However other variable had no significant effect in case of increasing illegal low-cost taxi. Besides the safety and comfort, steady job for the operators, provision of continuous, individual and door to door service system are the main reasons for increasing the illegal low-cost taxi in the study area. Finally, the researcher concludes with the requirement of some necessary action from the responsible authority on vehicular regulation for the improvement of the local public transport system in Bangladesh.