ARTICLE | doi:10.20944/preprints201811.0452.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: DTCS; dead-time compensation; trapezoidal compensation voltage; dead-time effects; three-phase VSI compensation
Online: 19 November 2018 (10:51:21 CET)
This paper proposes a novel three-phase voltage source inverter dead-time compensation strategy for accurate compensation in wide current regions of the inverter. In particular, an analysis of the output voltage distortion of the inverter, which appears as parasitic components of the switches, has been conducted for proper voltage compensation in the low current region, and an on-line compensation voltage controller has been proposed. Also, a new trapezoidal compensation voltage implementation method using the current phase is proposed to simplify realizing the trapezoidal shape of the three-phase compensation voltages. Finally, when the proposed dead-time compensation strategy is applied, the maximum phase voltage magnitude in the linear modulation voltage regions is defined to achieve smooth operation even at high modulation index. Simulations and experiments were conducted to verify the performance of the proposed dead-time compensation scheme.
REVIEW | doi:10.20944/preprints202209.0303.v1
Subject: Medicine And Pharmacology, Dermatology Keywords: Ultraviolet irradiation; Dead Sea; psoriasis; photoclimatotherapy
Online: 20 September 2022 (10:23:03 CEST)
The Dead Sea basin is the lowest terrestrial site on the globe and is internationally recognized as a photoclimatotherapy center. Since the last century, questions raised regarding the possible presence of a unique incident ultraviolet irradiation, allowing successful treatment of psoriasis, atopic dermatitis and other dermatological diseases. Aim: Determine the characteristics of the solar ultraviolet irradiation and understand the mechanism of action of photoclimatotherapy while applying the results to clinical protocols of treatment. Methods: A meteorological station was established at the Dead Sea basin to continuously measure global, UVB and UVA irradiation. The same irradiation parameters are also being monitored continuously by a set of identical ultraviolet irradiation instruments installed on the campus of the Ben-Gurion University of the Negev, in Beer Sheva. Results: This study details the results of these long-term measurements, ae well as their correlation with the success obtained by clinicians treating psoriasis patients. Conclusions: A database of more than 25 years has enabled the medical staff to establish tailor-made protocols for sun-exposure time intervals as a function of particular month and hour of day. The availability of such information has significantly improved the results of photoclimatotherapy for psoriasis and at the same time increasing the safety of sun-exposure at the Dead Sea.
ARTICLE | doi:10.20944/preprints202304.0446.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: Solar Electricity increase; Channel Mediterranean Dead Sea; water desalination.
Online: 17 April 2023 (10:33:05 CEST)
Currently, the Israeli energy industry faces the challenge of a considerable increase in solar electricity production. Being a relatively isolated system, the significant expansion of solar electricity may cause problems with electricity quality. The electrical storage installation can resolve this problem. In Israel's situation, the optimal solution can be the creation of a channel between the Mediterranean and the Dead Sea. The channel can solve three closely related problems: the increased production of desalinated water for domestic, industrial, and agricultural needs; the prevention of a permanent Dead Sea level decline and its imminent disappearance; the development of hydro-pumping electrical storage stations; and the creation of numerous PV facilities in the Negev area for national electricity generation. However, a detailed analysis should be done for the estimation of the possible increase of solar electric generation with the consideration of a stochastic PV outcome and a potential ability to use the Dead Sea for the brine discharge from electrical hydro-storage plants.
ARTICLE | doi:10.20944/preprints201812.0225.v1
Subject: Engineering, Energy And Fuel Technology Keywords: pipeline; transportation; trailing oil; CFD; dead-leg; modified formula;
Online: 18 December 2018 (16:21:13 CET)
Trailing oil is the tail section of contamination. There are two main reasons for the formation of trailing oil, one is the effect of laminar flow boundary layer, the other is the outflow of the preceding batch remained in the dead-legs. In the batch transportation of refined oil, under the action of viscous force, the preceding batch forms laminar boundary layer near the pipe wall and stays on the pipe wall, resulting in the phenomenon of contamination trailing and formation of trailing oil. When oil passes through the valve chamber of the oil transportation station, dead-leg will be formed. Due to gravity and convection diffusion, preceding batch flowing from dead-legs will form trailing oil in the pipeline. The phenomenon of trailing oil exists in the process of batch transportation, which will have an effect on the quality of oil. In this paper, Reynolds time-averaged method is used to simulate turbulence.Computational Fluid Dynamics(CFD) software is used to simulate different flow rates and bypass lengths to obtain contamination-related experimental data.Matlab software is used to perform multi-nonlinear regression for the oil substitution time, the length of the bypass and the flow rate. The formula for calculating the length of the trailing oil produced by the dead-leg is obtained. The modified formula for calculating the length of the contamination is obtained by combining the existing formula for calculating the length of the contamination.
ARTICLE | doi:10.20944/preprints201710.0086.v2
Subject: Engineering, Electrical And Electronic Engineering Keywords: cluster head; dead node; random; vicinity; modulation; index; survival; overhead
Online: 23 October 2017 (08:06:47 CEST)
As Heterogeneous Wireless Sensor Network (HWSN) fulfill the requirements of researchers in the design of real life application to resolve the issues of unattended problem. But, the main constraint face by researchers is energy source available with sensor nodes. To prolong the life of sensor nodes and hence HWSN, it is necessary to design energy efficient operational schemes. One of the most suitable routing scheme is clustering approach, which improves stability and hence enhances performance parameters of HWSN. A novel solution proposed in this article is to design energy efficient clustering protocol for HWSN, to enhance performance parameters by EECPEP-HWSN. Propose protocol is designed with three level nodes namely normal, advance and super node respectively. In clustering process, for selection of cluster head we consider three parameters available with sensor node at run time, i.e., initial energy, hop count and residual energy. This protocol enhance the energy efficiency of HWSN, it improves performance parameters in the form of enhance energy remain in the network, force to enhance stability period, prolong lifetime and hence higher throughput. It is been found that proposed protocol outperforms than LEACH, DEEC and SEP with about 188, 150 and 141 percent respectively.
ARTICLE | doi:10.20944/preprints202303.0519.v1
Subject: Environmental And Earth Sciences, Water Science And Technology Keywords: dissolved sulfide; iron; hypoxia; buffering capacity; environmental restoration; coastal waters; Mikawa Bay; dead zone
Online: 30 March 2023 (02:58:33 CEST)
This study examined the spatial-temporal distribution of sulfur and iron compounds (dissolved sulfide, iron sulfide, and ionized iron) in sediments from April 2015 to March 2016 at four stations in Mikawa Bay, Japan. Seasonal changes were observed in dissolved sulfide, iron sulfide, and ionized iron in the upper part of the sediment (0–4 cm depth) at all stations. The maximum concentration in the upper part of the central bay was 2.8 mmol L-1. The maximum values of dissolved sulfide (ranging from 1.4 to 8.1 mmol L-1) at stations located in a water way varied among stations. The iron sulfide concentration in the upper part of the sediment at a station where dissolved sulfide concentration in the waterway was relatively low exceeded that at other stations in the waterway during spring to summer. Ionized iron concentration was highest at the station where the dissolved sulfide concentration was low. The study results suggest that iron plays an important role in determining the magnitude of dissolved sulfide accumulation in sediments by binding with dissolved sulfide. The results imply the possibility of mitigating the accumulation of free sulfides, which causes extreme hypoxia, by artificially adding sufficient iron to the seabed.
Subject: Computer Science And Mathematics, Computer Science Keywords: Indoor Localization; Sensor Fusion; Multimodal Deep Neural Network; Multimodal Sensing; WiFi Fingerprinting; Pedestrian Dead Reckoning
Online: 13 October 2021 (12:14:39 CEST)
Many engineered approaches have been proposed over the years for solving the hard problem of performing indoor localisation using smartphone sensors. However, specialising these solutions for difficult edge cases remains challenging. Here we propose an end-to-end hybrid multimodal deep neural network localisation system, MM-Loc, relying on zero hand-engineered features, learning them automatically from data instead. This is achieved by using modality-specific neural networks to extract preliminary features from each sensing modality, which are then combined by cross-modality neural structures. We show that our choice of modality-specific neural architectures is capable of estimating the location with good accuracy independently. But for better accuracy, a multimodal neural network fusing the features of early modality-specific representations is a better proposition. Our proposed MM-Loc solution is tested on cross-modality samples characterised by different sampling rates and data representation (inertial sensors, magnetic and WiFi signals), outperforming traditional approaches for location estimation. MM-Loc elegantly trains directly from data unlike conventional indoor positioning systems, which rely on human intuition.
ARTICLE | doi:10.20944/preprints202108.0177.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: Antibacterial composites; Antiadhesive composites; Poly-Pore; Split-mouth; Clinical trial; Live/dead staining; Bacterial viability
Online: 9 August 2021 (07:53:57 CEST)
The purpose of the study was to investigate the bacterial viability of the initial biofilm on the surface of experimental modified dental resin composites. Twenty-five healthy individuals with good oral hygiene were included in this study. In a split-mouth design, they received acrylic splints with five experimental composite resin specimens. Four of them were modified with either a novel polymeric hollow beads delivery system or methacrylated polymerizable Irgasan (Antibacterial B), while one specimen served as unmodified control (ST). The delivery system based on Poly-Pore® was loaded with one of the active agents Tego® Protect 5000 (Antiadhesive A), Dimethicone (Antiadhesive B) or Irgasan (Antibacterial A). All study subjects refrained from toothbrushing during the study period. Specimens were detached from the splints after 8h and given a live/dead staining before fluorescence microscopy. Friedman test and post-hoc Nemenyi test were applied with significance level at p < 0.05. In summary all materials but Antibacterial B showed a significant antibacterial effect compared to ST. In conclusion dental resin composites with Poly-Pore loaded active agents show antibacterial effectiveness in situ.
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: brain death; brain-dead; brainstem lesions; posterior fossa; ancillary tests; EEG; cerebral blood flow (CBF); Jahi McMath
Online: 23 March 2020 (05:43:44 CET)
Brain death (BD) concept has been increasingly widely accepted beginning since the late 1950s, but several controversies have appeared when intracranial pathology is localized to the posterior fossa. In the presence of a primary supratentorial brain lesion, a severe forebrain lesion is combined with either the subsequent gradual loss of brainstem function, due to rostrocaudal transtentorial brain herniation. In secondary brain lesions (i.e., cerebral hypoxia), the brainstem is also affected like the forebrain. However, a minority of patients with a primary infratentorial brain lesion (i.e., basilar artery thrombosis or brainstem or cerebellar bleeds) may retain cerebral blood flow and EEG activity. In this article I discuss that if a brainstem lesion does not provoke a massive increase of intracranial pressure there may be no complete cerebral circulatory arrest, explaining the preservation of EEG activity, evoked potentials, and autonomic function. I also discuss the case of Jahi McMath who was declared brain-dead, but ancillary tests, performed 9 months after initial brain insult, showed conservation of intracranial structures, EEG activity, and autonomic reactivity to “Mother Talks” stimulus, rejecting the diagnosis of BD. Jahi McMath’s MRI study demonstrated a huge lesion in the pons. Some authors have argued that in patients with primary brainstem lesions it might be possible to find a in some cases partial recover of consciousness, even fulfilling clinical BD criteria. This was the case in Jahi McMath. Further research and discussion are necessary about the use of ancillary tests in BD diagnosis in primary posterior fossa lesions.
ARTICLE | doi:10.20944/preprints202305.1934.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Induction motor; PWM control; SV-PWM; THD; torque ripple; approximation; voltage source inverter; dead-band; electromagnetic torque; stator current
Online: 26 May 2023 (12:02:00 CEST)
This article presents a harmonic analysis of the stator currents of a squirrel-cage in-15 duction motor fed by a voltage source inverter with PWM space vector control (SV-PWM). The 16 influence of PWM switching frequency and dead time (dead-band) of controlled transistors on 17 THD and electromagnetic torque ripple is shown. The aim is to determine the lowest switching 18 frequency of the transistors for which the drive will operate correctly. Characteristics were de-19 termined as functions in the form of THD ( ), where the least square approximation was 20 used for stator current measurements when the PWM switching frequency is changed. The ap-21 proximations were realized for simulation and experimental results. To clarify the results, the 22 operation of hardware PWM circuits in microcontrollers was analyzed.
ARTICLE | doi:10.20944/preprints202305.0231.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: breeding strategy; dark-light cycles; dead co-twin; early fetal loss; selection index; spontaneous twin reduction; standardized transmitting ability
Online: 4 May 2023 (08:20:36 CEST)
Twin pregnancies are highly undesirable in dairy cattle; they compromise the health and wellbeing of a cow, and its incidence dramatically impairs the farm economy. Recently, a genomic prediction for twin pregnancies has been developed. The objective of this study was to assess cow, environmental and management risk factors affecting the incidence of twin pregnancies in high-producing dairy cows in their first lactation, with special emphasis placed on the genomic prediction values for twin pregnancy. Our study population of primiparous cows proved valuable in identifying factors other than genomic predictive values influencing the twin pregnancy rate. The odds ratio for twin pregnancy was 0.85 (p <0.0001) for each unit of a prediction value increase, 3.5 (p = 0.023) for cows becoming pregnant during the negative photoperiod, and 0.33 (p = 0.016) for cows producing ≥42 kg of milk at AI, compared to the remaining cows producing <42kg of milk. As a general conclusion, the practical implication of our findings is that genomic prediction values can identify the risk of twin pregnancy at herd level. Given the cumulative effect of genomic selection, selecting for animals with reduced genetic risk of twin pregnancies can contribute to reduce its incidence in dairy herds.
ARTICLE | doi:10.20944/preprints202102.0461.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Dead pericarps; salinity; short episodes of high temperature; stress response; reproductive phase; seed abortion; Phyohormones; Climate change; Brassica juncea
Online: 22 February 2021 (11:48:15 CET)
Climate change is expected to increase the frequency and severity of abiotic stresses that lead to loss of crop yield. We investigated the effect of salinity (S), short episodes of high temperature (HS) and combination of S+HS at the reproductive phase on dead pericarps properties and yield of the crop plant Brassica juncea. Three intervals of HS resulted in massive seed abortion; seeds from salt-treated plants germinated poorly. Pericarp extracts of salt-treated plants reduced seed germination of B. juncea; all pericarp extracts completely inhibited seed germination of tomato and Arabidopsis; removal of pericarp extracts restored seed germination. HS reduced all metabolites accumulated in dead pericarps, except for upregulation of isomaltose and cellobiose. Salt induced alteration in metabolite levels including increase in proline, reduction in TCA intermediates and changes in phytohormone levels. Proteome analysis revealed hundreds of proteins stored in dead pericarps whose levels and composition were altered under salt stress. The integration of metabolic and proteomic data showed that changes in metabolites were highly correlated with changes in proteins involved in their biosynthetic pathways. Thus, besides providing a physical shield for seed/embryo protection dead pericarps store beneficial substances whose levels, composition and biological function are altered under stress, further highlighting the elaborated function of dead organs enclosing embryos in seed biology and ecology. The detrimental effect of HS on crop production might have implications for global food security in the face of climate change.
REVIEW | doi:10.20944/preprints201807.0432.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Seed coat; pericarps; floral bracts; glumes; dead organs enclosing embryos; seed germination; seedling establishment; hydrolytic enzymes; ROS detoxifying enzymes; cell wall modification enzymes; nutrients; phytohormones; nucleases; chitinases; Brassicaceae; Poaceae
Online: 26 July 2018 (09:53:41 CEST)
Plants have evolved a variety of dispersal units whereby the embryo is enclosed by various dead protective layers derived from maternal organs of the reproductive system including seed coats (integuments), pericarps (ovary wall, e.g., indehiscent dry fruits) as well as floral bracts (e.g. glumes) in grasses. Commonly, dead organs enclosing embryos (DOEEs) are assumed to provide a physical shield for embryo protection and means for dispersal in the ecosystem. In this review article, we will highlight recent studies showing that DOEEs of various species across families also have the capability for long-term storage of various substances including active proteins (hydrolases, ROS detoxifying enzymes), nutrients and metabolites that have the potential to support the embryo during storage in the soil and assist in germination and seedling establishment. We discuss a possible role for DOEEs as natural coatings capable of ‘engineering’ the seed microenvironment for the benefit of the embryo, the seedling and the growing plant.