ARTICLE | doi:10.20944/preprints202109.0227.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: PGRs; callus induction; indirect organogenesis
Online: 14 September 2021 (09:52:02 CEST)
Callus induction of F. moluccana (sengon) was still an obstacle to indirect organogenesis regeneration. The purpose of the study was to determine the callus induction formation from root fragments of F. moluccana plantlets. Primary explants (fragments of roots) were cultivated on MS induction basal media and three concentration combination of PGRs (BAP and NAA): 0.5 ml/l BAP; 0,1 ml/l NAA (single PGR); and combination of 0.5 ml/l BAP + 0.1 ml/l NAA (double PGR). When roots were used as explants, high formation rates of callus (more than 70%) were obtained. Highest formation rates of callus were in NAA added at all clones (12 clones), then BAP added (7 clones) and BAP + NAA added (5 clones). The results indicated that BAP and NAA concentrations used in the media were influence the producing callus and affect the amount of callus produced from roots of sengon. The addition of NAA also gives higher callus proliferation results than the addition of BAP or the addition of a combination of the two hormones. The results indicated that BAP and NAA concentrations used in the media were influence the producing callus and affect the amount of callus produced from roots of sengon.
ARTICLE | doi:10.20944/preprints202307.1989.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: dairy cow; broken rice; indirect calorimetry; energy
Online: 28 July 2023 (10:16:06 CEST)
The objectives of this research were to determine 1) the energy contents of broken rice in dairy cows by animal calorimetry and 2) the effects of various levels of broken rice in diets on dairy cow performance. Four multiparous Holstein-Friesian crossbred cows at 70 ± 31 (mean ± SD) days in milk were assigned according to a 4 × 4 Latin square design with four periods. The four treatments included a diet substitution with broken rice on a 0, 12, 24, and 36% dry matter basis in the basal ration. Indirect calorimetry with a ventilated head box respiration system was used to determine energy metabolism. The substitution of broken rice in the diet did not affect dry matter intake, milk yield, milk composition, feed efficiency or energy balance (p > 0.05). Increasing broken rice substitution in the diet resulted in a linear increase in enteric methane energy losses and digestibility of dry matter, organic matter, and fiber (p < 0.05), whereas the digestibility of crude protein and ether extract decreased (p < 0.05). The metabolizable energy requirement for maintenance was 504 kJ/kg metabolic body weight, and the efficiency of metabolizable energy used for lactation was 0.76. The estimated net energy value of broken rice for lactation was 8.68 MJ/kg. Our results indicated that increasing the proportion of broken rice in the diet up to 36% had no adverse effect on feed intake and production performance in dairy cows.
ARTICLE | doi:10.20944/preprints202303.0483.v1
Subject: Engineering, Energy And Fuel Technology Keywords: free energy; indirect thermodynamic cycle; non-equilibrium simulation
Online: 28 March 2023 (10:20:44 CEST)
Nonequilibrium work switching simulations and Jarzynski’s equation are a reliable method to compute free energy differences, ΔAlow→high, between two levels of theory, such as a pure molecular mechanical (MM) and a quantum mechanical/molecular mechanical (QM/MM) description of a system of interest. Despite the inherent parallelism, the computational cost of this approach can quickly get very high. This is particularly true for systems where the core region, the part of the system to be described at different levels of theory, is embedded in an environment, such as explicit solvent water. We find that even for relatively simple solute–water systems, switching lengths of at least 5 ps are necessary to compute ΔAlow→high reliably. In this study, we investigate two approaches towards an affordable protocol, with emphasis on keeping the switching length well below 5 ps. Inserting a hybrid charge intermediate state with modified partial charges which resembles the charge distribution of the desired high level makes it possible to obtain reliable calculations with 2 ps switches. Attempts using step-wise linear switching paths, on the other hand, did not lead to improvement, i.e., faster convergence for all systems. To understand these findings, we analyzed the solutes’ properties as a function of partial charges used, the number of waters in direct contact with the solute, and studied the time needed for water molecules to reorient themselves upon a change in the solute’s charge distribution.
ARTICLE | doi:10.20944/preprints201808.0026.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: AMPK; liver; lipid metabolism; fatty acid oxidation; indirect calorimetry
Online: 1 August 2018 (16:06:39 CEST)
The energy sensor AMP-activated protein kinase (AMPK) is a key player in the control of energy metabolism. AMPK regulates hepatic lipid metabolism through the phosphorylation of its well-recognized downstream target acetyl CoA carboxylase (ACC). Although AMPK activation is proposed to lower hepatic triglyceride (TG) content via the inhibition of ACC to cause inhibition of de novo lipogenesis and stimulation of fatty acid oxidation (FAO), its contribution to the inhibition of FAO in vivo has been recently questioned. We generated a mouse model of AMPK activation specifically in the liver achieved by expression of a constitutively active AMPK using adenoviral delivery. Indirect calorimetry studies revealed that liver-specific AMPK activation is sufficient to induce a reduction in the respiratory exchange ratio and an increase in FAO rates in vivo. This led to a more rapid metabolic switch from carbohydrate to lipid oxidation during the transition from fed to fasting. Finally, mice with chronic AMPK activation in the liver display high fat oxidation capacity evidenced by increased [C14]-palmitate oxidation and ketone body production leading to reduced hepatic TG content and body adiposity. Our findings suggest a role for hepatic AMPK in the remodeling of lipid metabolism between the liver and adipose tissue.
ARTICLE | doi:10.20944/preprints201705.0210.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: pharmacokinetics; tissue distribution; indirect competitive enzyme-linked immunosorbent assay; puerarin
Online: 30 May 2017 (07:47:09 CEST)
Puerarin (PUE) is a compound isolated from the roots of Pueraria lobata. We studied the pharmacokinetics and tissue distribution kinetics of PUE in Sprague-Dawley rats following intraperitoneal administration of three concentrations. Indirect competitive ELISA based on an anti-PUE monoclonal antibody was used to determine the concentration of PUE in the blood, heart, liver, spleen, lung, kidney, hippocampus, cerebral cortex, and striatum. The plasma and tissue distribution kinetic characteristics following a single injection of PUE (20, 40, and 80 mg/kg) were calculated using a non-compartment model. In the high-dose (80 mg/kg) and medium-dose (40 mg/kg) groups, the kinetic profile of PUE in blood and kidney samples showed two absorption peaks, while that of the other tissues showed only one peak. In the low-dose (20 mg/kg) group, there was only one peak, irrespective of the sample type. Pharmacokinetic parameters such as the area under the curve, Cmax, and Tmax varied according to the administered dose. AUC and Cmax values increased dose-dependently. PUE was widely distributed in areas of the brain such as the hippocampus, cerebral cortex, and striatum, providing a foundation for guiding the use of PUE in the treatment of cerebral ischaemic stroke and neurodegenerative diseases.
ARTICLE | doi:10.20944/preprints202308.0979.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: image processing; K-means clustering algorithm; Traversal algorithm; Indirect solution method
Online: 14 August 2023 (08:57:37 CEST)
The utilization of tempered blast furnace (BF) slag through the direct fiber forming process to create high-value thermal insulation materials offers a dual benefit: it efficiently harnesses the latent heat within unused slag and substantially enhances the value of blast-furnace slag utilization. However, gauging the melting properties of iron slag under high temperatures is a challenge. In this study, we explore the melting behavior of SiO2 within a high-temperature molten pool. We employ dynamic visual data (video stream) captured via a non-contact charge coupled device (CCD) video recording system to extract SiO2 contours through image processing. The change in image centroid characteristics is used to establish a convolution function relationship, and MATLAB's traversal search algorithm determines SiO2's centroid position. Given that SiO2 is proportionate to crucible pixels, the area of SiO2 is calculated through pixel statistics within these contours. Subsequently, we propose a new indirect method to process image information, yielding SiO2 volume and mass at different time points. An exponential fitting yields the melting rate function of SiO2. Finally, we compare this indirect method with shape from shading (SFS), quantitative characterization, and dimensional analysis techniques. We also discuss the strengths and limitations of each method. Our findings reveal that the indirect solution method presented here boasts straightforward calculation steps and imposes minimal image format requirements. This research provides theoretical and technical support for blast-furnace slag's direct fiber forming process.
ARTICLE | doi:10.20944/preprints202306.0618.v1
Subject: Engineering, Civil Engineering Keywords: Asphalt mixes; moisture damage; indirect tensile strength; polyethylene terephthalate; international standards
Online: 8 June 2023 (09:56:04 CEST)
Water damage is one of the main causes of roads’ deterioration throughout their service life. This effect harms the adhesion and cohesion parameters of the asphalt mix, which leads to a decrease in the structural and functional characteristics of the road surface. This research focuses on studying the water susceptibility of hot mix asphalt mixtures using three different procedures: (1) UNE-EN 12697-12, (2) ASTM D4867, and (3) AASHTO T-283. The tests are carried out on reference mixtures and mixtures modified with polyethylene terephthalate (PET) particles as an additive. The results indicate that the incorporation of 6% PET allows the limits established by the UNE-EN 12697-12 standards to be exceeded, reaching 86% of the tensile strength ratio (TSR). However, for the ASTM D4867 and AASHTO T-283 standards, the results obtained concerning the water susceptibility of the bituminous mixtures were not as satisfactory because the established minimum limits were not reached (< 75%), which indicates that the procedure applied in a test can significantly modify the results of a later application.
REVIEW | doi:10.20944/preprints202305.0369.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: SARS-CoV-2; clinical diagnostics; molecular assays; direct test; indirect test
Online: 5 May 2023 (14:07:20 CEST)
Due to species barriers and poor adaptability to new host environments, few pathogens cause global pandemics. But, SARS-CoV-2 is one exception with its high transmissivity and delayed onset of symptoms. Fortunately, the world was able to tap on the technologies especially the maturing RT-qPCR designed to combat SARS to launch an initial offensive on SARS-CoV-2. These initial efforts may have bought time for scientists to develop more refined diagnostic tests that specifically target SARS-CoV-2. This article describes the effort put forth by the biotech industry and academia in Singapore to develop diagnostic tests that aid the early detection of positive cases, and thereby help contain the virus. Direct tests such as RT-qPCR and antigen rapid test profile the virus nucleic acid and surface proteins, respectively. But, of equal importance in case detection and treatment is serological tests that measure the relative abundance of IgM and IgG which is indicative of infection phase and quality of immune response in positive cases. Other tests such as isothermal amplification, CRISPR-based diagnostics and breath tests are also in development or at initial field deployment, and would undoubtedly provide valuable use experience useful for the development of molecular assays to detect and combat the next pathogen of global concern.
ARTICLE | doi:10.20944/preprints202304.0954.v1
Subject: Engineering, Energy And Fuel Technology Keywords: Pore pressure cohesive element; Indirect fracturing; Natural fracture; Tectonic stress; Horizontal well position
Online: 26 April 2023 (04:12:13 CEST)
Indirect fracturing from roof rock to coal using a horizontal well is a new and promising technology for coalbed methane surface exploitation in soft and low-permeability coal seams. In order to study the propagation law of hydraulic fracture across the coal-rock interface, a pore pressure cohesive element is used to establish a numerical model for indirect fracturing. Combined with practical engineering in 3# coal seam in Xinjing mine in China, the propagation behavior of hydraulic fracture across the coal-rock interface was researched, and the range of horizontal well position for indirect fracturing was determined. The results show that: (1) the pore pressure cohesive element can be used to simulate accurately the interaction between hydraulic fracture and natural fracture, and the propagation of hydraulic fracture across the coal-rock interface. (2) As the vertical distance between the horizontal well and coal-rock interface decreases, the breakdown pressure of perforation decreases; while the injection pressure increases when the hydraulic fracture crosses the coal-rock interface. (3) For the indirect fracturing engineering in 3# coal seam in Xinjing mine, the vertical distance between the horizontal well and coal-rock interface should not be larger than 2.0m to make the hydraulic fracture propagate into the coal seams.
ARTICLE | doi:10.20944/preprints202012.0560.v1
Subject: Medicine And Pharmacology, Urology And Nephrology Keywords: hemodialysis; indirect forest therapy; emotion; fatigue; stress; heart rate variability; natural killer cells
Online: 22 December 2020 (12:42:59 CET)
(1) Background: Most hemodialysis patients may experience physiological and psychological stress. Exposure to nature has been previously reported to reduce the measures of psychological and physiological stress, and immune function. This study aimed to investigate psychological and physiological effects of integrated indirect forest therapy on chronic renal failure patients undergoing hemodialysis. (2) Methods: As a quasi-experiment, this study employed a nonequivalent control group, repeated measurements, and a non-synchronized design. A total of 54 participants were included: 26 and 28 in the experimental and control groups, respectively. During hemodialysis, five types of forest therapy stimuli (visual, auditory, olfactory, tactile, and motor) were applied 3 times per week for 4 weeks during 15-minute sessions. (3) Results: Positive but not negative emotion measures differed between the groups after the intervention. Fatigue and physiological stress levels were significantly reduced in the experimental group, whereas no significant difference was found between the groups on the measures of psychological stress. Activation of both the parasympathetic and sympathetic nervous systems was similar in both groups, as was the number of natural killer cells. (4) Conclusion: Integrated indirect forest therapy may help increase positive emotions and reduce fatigue and stress levels during hemodialysis in patients with chronic renal failure.
ARTICLE | doi:10.20944/preprints202307.0146.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: charophytes, phytocenosis, prodromus, Brown-Blanquet approach, indirect ordination analysis, Sea of Azov, Black Sea
Online: 4 July 2023 (10:06:20 CEST)
Within the eastern part of the Black Sea and Sea of Azov, the vegetation of charophytes was studied using the Brown-Blanquet approach. For the first time, five communities are described, including three associations and two subassociations from the alliance Charion canescentis Krausch 1964, the order Charetalia intermediae Sauer 1937, and the class Charetea intermediae F. Fukarek 1961. Diagnoses of the described syntaxa are given. A comparison with the Baltic and Mediterranean communities of charophytes is made. It is shown that all the Azov-Black Sea communities with the dominance of charophytes, in contrast to Western European ones, include Lamprothamnium papulosum with high constancy. At the same time, the communities of the southern seas of Russia are characterized by a lower occurrence and abundance of higher aquatic plants (except for Nanozostera noltei) and a slightly higher occurrence of red and green algae. An indirect ordination analysis showed the ecological isolation of the described phytocenoses and revealed two main factors influencing the floristic composition of communities – the granulometric composition of bottom sediments and water eutrophication.
ARTICLE | doi:10.20944/preprints202109.0226.v1
Subject: Engineering, Energy And Fuel Technology Keywords: Low-thrust trajectories; bang-bang control; electric propulsion; constant specific impulse; indirect method; direct method
Online: 14 September 2021 (09:48:25 CEST)
Recent advance in electric propulsion systems have demonstrated that these engines can be used for for long-duration interplanetary voyages. Constant specific impulse engine described as a thrust-limited engine is an example of this type of engine, processing the ability to operate at a constant level of impulse. The determination of minimum-fuel, planar heliocentric Earth-to-Mars low-thrust trajectories of spacecraft using a constant specific impulse is discussed considering the first-order necessary conditions derived from Lawden’s primer vector theory. The minimum-fuel low-thrust Earth-to-Mars optimization problem is then solved in two-dimensional, heliocentric frame using both indirect and direct methods. In the indirect method, two-point-boundary-value problems are derived to solve boundary value problems for ordinary differential equations. In the direct method, a general-purpose optimal control software called GPOPS-II is adopted to solve these optimal control problems. Numerical examples using two different optimization methods are presented to demonstrate the characteristics of minimum-fuel planar low-thrust trajectories with on-off-on thrust sequences at three chosen flight times and available maximum powers. The results are useful for broad trajectory search in the preliminary phase of mission designs.
ARTICLE | doi:10.20944/preprints202103.0454.v1
Subject: Social Sciences, Psychology Keywords: unconscious; consciousness; quantum-like models; decision making; indirect measurement scheme; open quantum systems; sensation; perception
Online: 17 March 2021 (16:58:30 CET)
We present the mathematical model of cooperative functioning of unconscious and consciousness. The model is based on the theory of open quantum systems. Unconscious and consciousness are treated as bio-information systems. The latter plays the role a measurement apparatus for the former. States of both systems are represented in Hilbert spaces. Consciousness performs measurements on the states which are generated in unconscious. This process of unconscious-conscious interaction is described by the scheme of indirect measurements. This scheme is widely used in quantum information theory and it leads to the theory of quantum instruments (Davis-Lewis-Ozawa). Our approach is known as quantum-like modeling. It should be sharply distinguished from modeling of genuine quantum physical processes in biosystems, in particular, in the brain. In the quantum-like framework, the brain is a black box processing information in the accordance with the laws of quantum theory. During the last 10-15 years this framework has been actively used in cognition, psychology, decision making, social and political sciences. The quantum-like scheme of unconscious-consciousness functioning has already been explored for sensation-perception modeling.
ARTICLE | doi:10.20944/preprints202009.0570.v1
Subject: Engineering, Civil Engineering Keywords: Asphalt concrete; Glass wool fibers; indirect tensile strength; tensile strength ratio; Kim test; Marshall test
Online: 24 September 2020 (08:01:47 CEST)
Nowadays, in order to improve asphalt pavement performance, durability and reduce environmental pollution caused by asphalt binder, many researchers are studying to modify asphalt concrete (AC) and find alternative paving materials to extend service life of asphalt pavement. One of the successful materials used in a modification of AC are fibers. Different types of fibers have been reinforced in AC mixture and improvements have been observed. This research studies the performance of glass wool fiber reinforced in a dense-graded asphalt mixture. Generally, glass fibers are known to have excellent mechanical properties such as high tensile modulus, 100% elastic recovery and a very high tolerance to heat. The glass wool fibers are commonly used as a thermal insulation material. In this research to evaluate the performance of glass wool fiber in AC, laboratory tests Marshall mix design test, Indirect tensile strength (IDT), Tensile strength ratio (TSR) and Kim test were conducted to determine a proper mix design, tensile properties, moisture susceptibility, rutting and fatigue behaviors. Results show that addition of glass wool fibers does affect the properties of AC mixture. The use of glass wool fibers showed a positive consistence results, in which it improved the moisture susceptibility and rutting resistance of the AC. Also result showed addition of fiber increased tensile strength and toughness which indicates that fibers have a potential to resist distresses that occur on a surface of the road as a result of heavy traffic loading. The overall results showed that addition of glass wool fiber in AC mixture is beneficial in improving properties of AC pavements.
ARTICLE | doi:10.20944/preprints201906.0287.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: nanocomposite, metal-polymer-interface, multilayer, structure-function correlation, indirect band gap, GISAXS, GIWAXS, UV-Vis.
Online: 27 June 2019 (11:11:33 CEST)
A new strategy to nanoengineer gold/fluorocarbon multilayer (ML) nanostructures is reported. We have investigated the morphological changes occuring at the metal-polymer interface in multilayer structures with varying volume fraction of gold (Au) and the kinetic growth aspect of the microscale properties of nano-sized Au in plasma polymer fluorocarbon (PPFC). Investigations were carried out at various temperatures and annealing time by means of grazing incidence small-angle and wide-angle X-ray scattering (GISAXS and GIWAXS). We have fabricated a series of multilayers with variying volume fraction (0.12, 0.27, 0.38) of Au and bilayer periodicity in ML structure. They show an interesting granular structure consisting of nearly spherical shaped nanoparticles within the polymer layer. The nanoparticle (NP) morphology changes due to the collective effects of NPs diffusion within ensembles in the in-plane vicinity and inter-layer with increasing temperature. The in-plane NPs size distinctly increases (from 1.9 to 4 nm) with increasing temperature. The NPs become more spherical thus reducing the surface energy. Linear growth of NPs with temperature and time shows diffusion-controled growth of NPs in the ML structure. The structural stability of the multilayer is controlled by the volume ratio of the metal in polymer. At room temperature UV-Vis shows a blueshift of the plasmon peak from 560 nm in ML Au/PTFE_1 to 437 nm in Au/PTFE_3. We have identified the fabrication and post-deposition annealing conditions to limit the Local Surface Plasmon resonance (LSPR) shift (from 〖∆λ〗_LSPR=180 nm (Au/PTFE_1) to 〖∆λ〗_LSPR=67 nm (Au/PTFE_3 ML)) and their optical response over a wide visible wavelength range. A variation in the dielectric constant of the polymer in precence of varying Au inclusion is found to be the main factor affecting the LSPR frequency. Our finding may provide insights in Nano engineering ML structure can be useful to systematically control the growth of NPs in polymer matrix.
ARTICLE | doi:10.20944/preprints202303.0194.v1
Subject: Medicine And Pharmacology, Dietetics And Nutrition Keywords: Berries; anthocyanins; functional foods; obesity; healthy volunteers; indirect calorimetry; meal tolerance test; insulin sensitivity; glucose tolerance
Online: 10 March 2023 (09:50:56 CET)
Obesity in the United States continues to worsen. Anthocyanin-rich fruits and vegetables provide a pragmatic dietary approach to slow its metabolic complications. Given American diet patterns, foods with high anthocyanin content could address dose-response challenges. In a placebo-controlled, randomized, crossover pilot study, determine the effect of 100% elderberry juice on measures of indirect calorimetry (IC), and insulin sensitivity/glucose tolerance. Overweight and obese adults were randomized to a 5-week study which included two 1-week periods of twice-daily elderberry juice (EBJ), or sugar-matched placebo consumption separated by a 3-week washout period. Following each 1-week test period, IC and insulin sensitivity/glucose tolerance was measured with a 3-hour meal tolerance test (MTT). Treatment differences were tested with linear mixed modeling. 22 prospective study volunteers (18F/4M) attended recruitment meetings, 10 volunteers completed the protocol, and 9 were analyzed for treatment differences. EBJ was well tolerated and compliance was 99.6%. Six IC measures (intervals) were created which coincided with 10-20 minute gaseous samplings in-between MTT blood samplings. Average CHO oxidation was significantly higher during the MTT after 1-week EBJ consumption (3.38 vs. 2.88 grams per interval, EBJ vs. placebo, p = 0.0113). Conversely, average fat oxidation was significantly higher during the MTT after 1-week placebo consumption (1.17 vs 1.47 grams per interval, EBJ vs. placebo, p = 0.0189). This was in-line with a significantly lower average respiratory quotient after placebo treatment (0.87 vs. 0.84, EBJ vs. placebo, p = 0.0114). Energy expenditure was not different. There was no difference in serum glucose or insulin response between treatments. This pilot study of free-living volunteers describes significant change in IC but not insulin sensitivity with an EBJ intervention. Controlled feeding and increased sample size will help determine the utility of EBJ on these outcomes.
ARTICLE | doi:10.20944/preprints202302.0293.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: Black carbon; Aethalometer; Black summer wildfires 2019-2020; Radiative forcing; Aerosol direct effect; Aerosol indirect effect
Online: 17 February 2023 (03:17:15 CET)
The emission of black carbon (BC) particles, which cause atmospheric warming by affecting radiation budget in the atmosphere, is the result of an incomplete combustion process of organic materials. The recent wildfire event during the summer 2019-2020 in South-Eastern Australia was unprecedented in scale. The wildfires lasted for nearly 3 months over large areas of the two most populated states of New South Wales and Victoria. This study on the emission and dispersion of BC emitted from the biomass burnings of the wildfires using the Weather Research Forecast – Chemistry (WRF-Chem) model is aimed to determine the extent of the BC spatial dispersion and ground concentration distribution and the effect of BC on air quality and radiative transfer at the top of the atmosphere, the atmosphere and on the ground. The predicted aerosol concentration and AOD are compared with the observed data from the New South Wales Department of Planning and Environment (DPE) aethalometer and air quality network and from remote sensing data. The BC concentration as predicted from WRF-Chem model is in general less than the observed data as measured from the aethalometer monitoring network, but the spatial pattern corresponds well, and the correlation is relatively high. The total BC emission into the atmosphere during the event and the effect on radiation budget were also estimated. This study shows that the summer 2019-2020 wildfires affect not only the air quality and health impact on the east coast of Australia but also short-term weather in the region via aerosol interactions with radiation and cloud.
REVIEW | doi:10.20944/preprints201907.0335.v1
Subject: Engineering, Energy And Fuel Technology Keywords: power take-off; wave energy converters; direct-drive; indirect drive; linear generator; hydrodynamics; energy harvesting efficiency
Online: 29 July 2019 (10:42:54 CEST)
Ocean wave energy conversion as one of the renewable clean energy sources is attracting the research interests of many people. This review introduces different types of power take-off technology of wave energy converters. The main focus is the linear direct drive power take-off devices as they have the advantages for ocean wave energy conversion. The designs and optimizations of power take-off systems of ocean wave energy converters have been studied from reviewing the recently published literature. Also, the simple hydrodynamics of wave energy converters have been reviewed for design optimization of the wave energy converters at specific wave sites. The novel mechanical designs of the power take-off systems have been compared and investigated in order to increase the energy harvesting efficiency.
ARTICLE | doi:10.20944/preprints202309.1644.v1
Subject: Chemistry And Materials Science, Ceramics And Composites Keywords: fly ash; fiber reinforcement; cement stabilization; compressive strength; indirect tensile strength; flexural strength; resilient modulus; subbase and base.
Online: 25 September 2023 (06:36:19 CEST)
It is necessary to address the scarcity of crushed stones for pavement structural layers. So fly ash can be proved to be promising solution as more than 270 tonnes of fly ash is generated in India. Though, numerous research has been conducted for the use of fly ash intreated and untreated form, high volume of fine particles and brittleness of the stabilized fly ash pose a great problem for its use in subbase and base. Moreover, stiffness or modulus of stabilized fly ash is vital elastic parameter which is used for mechanistic pavement design. Hence, in this study an extensive experimental investigation is carried out to study its strength and stiffness properties such as compressive strength, indirect tensile strength and flexural strength, cyclic indirect tensile modulus and flexural modulus of fiber reinforced cement stabilized fly ash, stone dust, aggregate mixtures. The stone dust and aggregates have been added to enhance the gradation of the composite’s mixture. The study presents the effect of fiber on strength and stiffness properties. The experimental result reveals that addition of polypropylene (PP) fibers up to 0.25 wt.% enhances the compressive strength and any further addition of fiber results in decrease of the strength. However, indirect tensile strength and flexural strength increases with increase in fiber percentage up to 0.5 wt.%. Cement content is observed to be the dominant parameter for stabilized materials. Suitable relationships have been developed between strength and modulus parameters for stabilized mixtures. Based on the strength and stiffness study, 70% fly ash and 30% stone dust-aggregate and 60% fly ash and 40% stone dust-aggregate with 6% cement can be considered for the base layer. Based on the indirect tensile strength and flexural strength behavior, 0.35% is considered as the optimum fiber percentage.
ARTICLE | doi:10.20944/preprints202305.0024.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: Key Words Putrescine; spermidine; spermine; tri-lysine; tetra-lysine; penta-lysine; DNA-conformation; RNA-conformation; indirect buffer system
Online: 1 May 2023 (10:50:20 CEST)
AbstractPolyamines (PAs) including putrescine (PUT), spermidine (SPD) and spermine (SPM) are small, versatile molecules with two or more positively charged amino groups. Despite their importance for almost all forms of life, their specific roles in molecular and cellular biology remain partly unknown. The molecular structures of PAs suggest two presumable biological functions: (i) as potential buffer systems and (ii) as interactants with poly-negatively charged molecules like nucleic acids.The present report focuses on the question, whether the molecular structures of PAs are essential for such functions, or whether other simple molecules like small peptides with closely spaced positively charged side chains might be suitable as well. Consequently, we created titration curves for PUT, SPD, and SPM, as well as for oligolysines like tri-, tetra-, and penta-lysine. None of the molecules provided substantial buffering capacity at physiological intracellular pH values. Apparently, the most important mechanism for intracellular pH homeostasis in neurons is not a buffer system but is provided by the actions of the sodium-hydrogen and the bicarbonate-chloride antiporters.In a similar approach we investigated the interaction with DNA by following the extinction at 260 nm when titrating DNA with the above molecules. Again, PUT and tri-lysine were not able to interact with herring sperm DNA, while SPD and SPM were. Obviously, the presence of several positively charged groups on its own is not sufficient for the interaction with nucleic acids. Instead, the precise spacing of these groups is necessary for biological activity.
ARTICLE | doi:10.20944/preprints202002.0110.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: invasion ecology; biotic resistance; exotic plants; heterospecific pollen; reproductive interference; alien plants; indirect plant-plant interactions; Darwin's naturalization hypothesis
Online: 9 February 2020 (16:32:53 CET)
1. Heterospecific pollen interference has recently been proposed as a mechanism contributing to the success of alien invaders, as heterospecific pollen of alien plants interferes with the reproduction of natives by reducing fruit and seed set. However, no study has looked at the opposite interaction. Moreover, few studies have considered the roles of phylogenetic and trait distances between pollen donors and recipients. 2. We did a large multi-species experiment in which we used alien and native species both as pollen recipients and as pollen donors, and included phylogenetic as well as trait distance as explanatory variables. 3. We found that both alien and native recipients suffered from heterospecific pollen from donors of the opposite status in terms of seed and fruit set. Phylogenetic distance and trait distance both affected heterospecific pollen interference, but the effect depended on recipient and donor statuses. 4. We conclude that heterospecific pollen interference affects both native and alien recipients, thus indirectly altering community composition and increasing biotic resistance against invaders.
ARTICLE | doi:10.20944/preprints202108.0425.v1
Subject: Engineering, Civil Engineering Keywords: road pavement design; design based on materials science; material mineralogy; New-age (Nano) Modified Emulsions (NME); naturally available materials; material stabilisation; basic engineering requirements; Unconfined Compressive Strengths (UCS); Indirect Tensile Strengths (ITS); Retained Compressive Strengths (RCT) and; Retained Tensile Strengths (RTS)
Online: 23 August 2021 (10:38:52 CEST)
The use of naturally available materials not conforming to traditional specifications or standards, in the base and sub-base layers of road pavement structures, stabilised with New-age (Nano) Modified Emulsions (NME), have been tested, implemented and successfully verified through Accelerated Pavement Testing (APT) in South Africa. This was made possible through the development and use of a design procedure addressing fundamental principles and based on scientific concepts, which are universally applicable. The understanding of and incorporation of the chemical interaction between the mineralogy of the materials and a NME stabilising agent (compatibility between the chemistry of the reactive agents and material mineralogy) into the design approach is key to achieving the required engineering properties. Stabilised materials evaluation is done using tests indicative of the basic engineering properties (physics) of compressive strengths, tensile strengths and durability. This article describes the basic materials design approach developed to ensure that organofunctional nano-silane modified emulsions can successfully be used for pavement layer construction utilising naturally available materials, at a low risk. The enablement of the use of naturally available materials in all pavement layers can have a considerable impact on the unit cost and life-cycle costs of road transportation infrastructure. TRANSLATE with x English ArabicHebrewPolish BulgarianHindiPortuguese CatalanHmong DawRomanian Chinese SimplifiedHungarianRussian Chinese TraditionalIndonesianSlovak CzechItalianSlovenian DanishJapaneseSpanish DutchKlingonSwedish EnglishKoreanThai EstonianLatvianTurkish FinnishLithuanianUkrainian FrenchMalayUrdu GermanMalteseVietnamese GreekNorwegianWelsh Haitian CreolePersian TRANSLATE with COPY THE URL BELOW Back EMBED THE SNIPPET BELOW IN YOUR SITE Enable collaborative features and customize widget: Bing Webmaster Portal Back