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Records added in March 2023
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Showing records 1351 to 1375 of 12968. [First] Page: 51 52 53 54 55 56 57 58 59 Last
Additive Manufacturing of Astragaloside-Containing Polyurethane Nerve Conduits Influenced Schwann Cell Inflammation and Regeneration
Yueh-Sheng Chen, Shih-Sheng Chang, Hooi Yee Ng, Yu-Xuan Huang, Chien-Chang Chen, Ming-You Shie
March 28, 2023 (v1)
Keywords: anti-inflammatory, astragaloside, digital light processing, polyurethane, Schwann cells
The peripheral nervous system is the bridge of communication between the central nervous system and other body systems. Autologous nerve grafting is the mainstream method for repair of nerve lesions greater than 20 mm. However, there are several disadvantages and limitations of autologous nerve grafting, thus prompting the need for fabrication of nerve conduits for clinical use. In this study, we successfully fabricated astragaloside (Ast)-containing polyurethane (PU) nerve guidance conduits via digital light processing, and it was noted that the addition of Ast improved the hydrophilicity of traditional PU conduits by at least 23%. The improved hydrophilicity not only led to enhanced cellular proliferation of rat Schwann cells, we also noted that levels of inflammatory markers tumor necrosis factor-alpha (TNF-α) and cyclooxygenase-2 (COX-2) significantly decreased with increasing concentrations of Ast. Furthermore, the levels of neural regeneration markers were significantly enhanced... [more]
Evolving Container to Unikernel for Edge Computing and Applications in Process Industry
Shichao Chen, Mengchu Zhou
March 28, 2023 (v1)
Keywords: big data analytics, cloud computing, edge computing, fault diagnosis, industrial process, Industry 4.0, Internet of things, lightweight virtualization, Machine Learning, process industry
Industry 4.0 promotes manufacturing and process industry towards digitalization and intellectualization. Edge computing can provide delay-sensitive services in industrial processes to realize intelligent production. Lightweight virtualization technology is one of the key elements of edge computing, which can implement resource management, orchestration, and isolation services without considering heterogenous hardware. It has revolutionized software development and deployment. The scope of this review paper is to present an in-depth analysis of two such technologies, Container and Unikernel, for edge computing. We discuss and compare their applicability in terms of migration, security, and orchestration for edge computing and industrial applications. We describe their performance indexes, evaluation methods and related findings. We then discuss their applications in industrial processes. To promote further research, we present some open issues and challenges to serve as a road map for b... [more]
Effect of Surface Textures and Wettability on Droplet Impact on a Heated Surface
Satoshi Ogata, Ryo Nakanishi
March 28, 2023 (v1)
Subject: Materials
Keywords: boiling, evaporation, film boiling, leidenfrost temperature, surface texture, wettability
A liquid droplet can hover over a solid surface that is heated above the Leidenfrost point (LFP), at which an insulating vapor layer is formed that acts as a heat transfer barrier. Recent studies have reported that hierarchical micro- and nanoscale textures provide high wettability and significant LFP enhancement. However, such textures are often difficult and expensive to fabricate. Therefore, this study aimed to experimentally demonstrate LFP enhancement through the use of low-cost hierarchical textures. Surface textures were fabricated by coating SiO2 nanoparticles on stainless steel wire meshes. The droplet lifetime method was used to determine the LFP in a temperature range of 200 °C−490 °C. High-speed imaging (4000−23,000 fps) was performed for visualizing the impact behavior of a droplet. The LFP value of the nanocoated mesh surface was found to be greater than 490 °C. This enhanced LFP was 178 °C higher than that of a stainless steel surface and 38 °C higher than that of a sing... [more]
Solubility of Rare Earth Chlorides in Ternary Water-Salt Systems in the Presence of a Fullerenol—C60(OH)24 Nanoclusters at 25 °C. Models of Nonelectrolyte Solubility in Electrolyte Solutions
Nikolay A. Charykov, Viktor A. Keskinov, Kirill A. Tsvetkov, Ayat Kanbar, Konstantin N. Semenov, Lubov’ V. Gerasimova, Zhassulan K. Shaimardanov, Botagoz K. Shaimardanova, Natalia A. Kulenova
March 28, 2023 (v1)
Keywords: atomic absorption spectroscopy, chlorides of rare earth elements, electron spectrophotometry, eutonics, fullerenol, isothermal saturation in ampoules, modified Sechenov equation, salting-in effects, salting-out, solubility
The solubility in triple water-salt systems containing NdCl3, PrCl3, YCl3, TbCl3 chlorides, and water-soluble fullerenol C60(OH)24 at 25 °C was studied by isothermal saturation in ampoules. The analysis for the content of rare earth elements was carried out by atomic absorption spectroscopy, for the content of fullerenol—by electronic spectrophotometry. The solubility diagrams in all four ternary systems are simple eutonic, both consisting of two branches, corresponding to the crystallization of fullerenol crystal-hydrate and rare earth chloride crystal-hydrates, and containing one nonvariant point corresponding to the saturation of both solid phases. On the long branches of C60(OH)24*18H2O crystallization, a C60(OH)24 decreases by more than 2 orders of magnitude compared to the solubility of fullerenol in pure water (salting-out effect). On very short branches of crystallization of NdCl3*6H2O, PrCl3*7H2O, YCl3*6H2O, and TbCl3*6H2O, the salting-in effect is clearly observed, and the so... [more]
Holistic Approach to Design, Test, and Optimize Stand-Alone SOFC-Reformer Systems
Michael Höber, Benjamin Königshofer, Philipp Wachter, Gjorgji Nusev, Pavle Boskoski, Christoph Hochenauer, Vanja Subotić
March 28, 2023 (v1)
Keywords: chemical equilibrium calculations, electrochemical analysis, reforming processes, sector coupling, solid oxide fuel cell (SOFC), stand-alone system
Reliable electrical and thermal energy supplies are basic requirements for modern societies and their food supply. Stand-alone stationary power generators based on solid oxide fuel cells (SOFC) represent an attractive solution to the problems of providing the energy required in both rural communities and in rurally-based industries such as those of the agricultural industry. The great advantages of SOFC-based systems are high efficiency and high fuel flexibility. A wide range of commercially available fuels can be used with no or low-effort pre-treatment. In this study, a design process for stand-alone system consisting of a reformer unit and an SOFC-based power generator is presented and tested. An adequate agreement between the measured and simulated values for the gas compositions after a reformer unit is observed with a maximum error of 3 vol% (volume percent). Theoretical degradation free operation conditions determined by employing equilibrium calculations are identified to be st... [more]
Parallel Multiset Rewriting Systems with Distorted Rules
Cristina Sburlan, Dragoş-Florin Sburlan
March 28, 2023 (v1)
Subject: Other
Keywords: computational universality, distorted computation, multiset rewriting systems, promoters, robust computation
Most of the parallel rewriting systems which model (or which are inspired by) natural/artificial phenomena consider fixed, a priori defined sets of string/multiset rewriting rules whose definitions do not change during the computation. Here we modify this paradigm by defining level-t distorted rules—rules for which during their applications one does not know the exact multiplicities of at most t∈N species of objects in their output (although one knows that such objects will appear at least once in the output upon the execution of this type of rules). Subsequently, we define parallel multiset rewriting systems with t-distorted computations and we study their computational capabilities when level-1 distorted catalytic promoted rules are used. We construct robust systems able to cope with the level-1 distortions and prove the computational universality of the model.
Light as a Novel Inhibitor of Nitrite-Oxidizing Bacteria (NOB) for the Mainstream Partial Nitrification of Wastewater Treatment
Keugtae Kim, Yong-Gyun Park
March 28, 2023 (v1)
Subject: Environment
Keywords: AOB, blue light, light intensity, mainstream, NOB inhibition
Conventional biological nutrient removal processes in municipal wastewater treatment plants are energy-consuming, with oxygen supply accounting for 45−75% of the energy expenditure. Many recent studies examined the implications of the anammox process in sidestream wastewater treatment to reduce energy consumption, however, the process did not successfully remove nitrogen in mainstream wastewater treatment with relatively low ammonia concentrations. In this study, blue light was applied as an inhibitor of nitrite-oxidizing bacteria (NOB) in a photo sequencing batch reactor (PSBR) containing raw wastewater. This simulated a biological nitrogen removal system for the investigation of its application potential in nitrite accumulation and nitrogen removal. It was found that blue light illumination effectively inhibited NOB rather than ammonia-oxidizing bacteria due to their different sensitivity to light, resulting in partial nitrification. It was also observed that the NOB inhibition rates... [more]
Versatility of Reverse Micelles: From Biomimetic Models to Nano (Bio)Sensor Design
Melania-Liliana Arsene, Iuliana Răut, Mariana Călin, Maria-Luiza Jecu, Mihaela Doni, Ana-Maria Gurban
March 28, 2023 (v1)
Subject: Materials
Keywords: biomimetic, confinement, nano (bio)sensors, nanoparticles, reverse micelles, water dynamics
This paper presents an overview of the principal structural and dynamics characteristics of reverse micelles (RMs) in order to highlight their structural flexibility and versatility, along with the possibility to modulate their parameters in a controlled manner. The multifunctionality in a large range of different scientific fields is exemplified in two distinct directions: a theoretical model for mimicry of the biological microenvironment and practical application in the field of nanotechnology and nano-based sensors. RMs represent a convenient experimental approach that limits the drawbacks of the conventionally biological studies in vitro, while the particular structure confers them the status of simplified mimics of cells by reproducing a complex supramolecular organization in an artificial system. The biological relevance of RMs is discussed in some particular cases referring to confinement and a crowded environment, as well as the molecular dynamics of water and a cell membrane s... [more]
Agro-Food Residues and Bioethanol Potential: A Study for a Specific Area
Marina Basaglia, Massimiliano D’Ambra, Giuseppe Piubello, Veronica Zanconato, Lorenzo Favaro, Sergio Casella
March 28, 2023 (v1)
Keywords: agricultural waste streams, bioethanol, residual biomass, second-generation bioethanol plant, vine shoots, wheat straw, yeast
Bioethanol obtained from agro-food wastes could contribute to decrease the dependency on fossil resources, reduce the impact of fossil fuels on the environment, and mitigate the food versus fuel debate. This study is aimed to investigate the availability of residual inexpensive agro-food biomasses that could feed a second-generation bioethanol plant located in a specific area of North Eastern Italy. After the identification of all crops in the area, more than 40 agro-food residues were analyzed for their availability and compositions in terms of water, polysaccharides, and sugars potentially convertible into bioethanol. 574,166 Mg of residual wet lignocellulosic biomass corresponding to 297,325 Mg of dry material were found available for bioethanol conversion. The most promising substrates were wheat straw and vine shoots. Based on the chemical composition of residues, the potential attainable ethanol was determined. Theoretical potential ethanol production was estimated at nearly 72,0... [more]
Semi-Batch Gasification of Refuse-Derived Fuel (RDF)
Juma Haydary, Patrik Šuhaj, Michal Šoral
March 28, 2023 (v1)
Keywords: gasification, MSW, RDF, tar, wax
Gasification is a promising technology for the conversion of mixed solid waste like refuse-derived fuel (RDF) and municipal solid waste (MSW) into a valuable gas consisting of H2, CO, CH4 and CO2. This work aims to identify the basic challenges of a single-stage batch gasification system related to tar and wax content in the producer gas. RDF was first gasified in a simple semi-batch laboratory-scale gasification reactor. A significant yield of tars and waxes was received in the produced gas. Waxes were analyzed using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectrometry. These analyses indicated the presence of polyethylene and polypropylene chains. The maximum content of H2 and CO was measured 500 sec after the start of the process. In a second series of experiments, a secondary catalytic stage with an Ni-doped clay catalyst was installed. In the two-stage catalytic process, no waxes were captured in isopropanol and the total tar content decre... [more]
Change in Mixing Power of a Two-PBT Impeller When Emptying a Tank
Jacek Stelmach, Czesław Kuncewicz, Łukasz Adrian, Tomaš Jirout, Frantisek Rieger
March 28, 2023 (v1)
Keywords: axial impeller, increase of power consumption, tank emptying
The paper presents research on the phenomenon of an increase in mixing power during the emptying of a tank with two 6-PBT45° axial impellers in operation, located on a common shaft, pumping the liquid to the bottom of the mixing tank. A large increase in mixing power took place when the free surface of the liquid was just above the upper edge of one of the impellers (hp/D < 0.1). This increase was even more than 50% compared to the design power for a fully filled mixing vessel. Admittedly, high motor overload, while not very long, may damage it. The study investigated the instantaneous torques acting on the impeller shaft during the emptying of the tank and the velocity distributions in planes r-z. On their basis, the mechanism of the phenomenon observed was determined and correlation relationships were given that permitted the calculation of the numerical values of the power increase factors.
Protective Effect of Processed Polygoni multiflori Radix and Its Major Substance during Scopolamine-Induced Cognitive Dysfunction
Ji-Hyun Kim, Ji Hyun Kim, Mei Tong He, Su Cheol Kim, Kyung Pan Hwa, Kye Man Cho, Eun Ju Cho
March 28, 2023 (v1)
Keywords: 2,3,5,4′-tetrahydroxystilbene-2-O-β-glucoside, Alzheimer’s disease, cognitive dysfunction, processed Polygoni multiflori Radix
Alzheimer’s disease (AD) is the most common cognitive disorder in the elderly population. However, effective pharmacological agents targeting AD have not been developed. The processed Polygoni multiflori Radix (PPM) and its main active substance, 2,3,5,4′-tetrahydroxystilbene-2-O-β-glucoside (TSG), has received considerable attention, majorly due to its neuroprotective activities against multiple biological activities within the human body. In this study, we provide new evidence on the therapeutic effect of PPM and TSG during cognitive impairment by evaluating the ameliorative potential of PPM and TSG in scopolamine-induced amnesia in ICR mice. PPM (100 or 200 mg/kg) was orally administered during the experimental period (days 1−15), and scopolamine was intraperitoneally injected to induce cognitive deficits during the behavioural test periods (days 8−15). The administration of PPM and TSG significantly improved memory loss and cognitive dysfunction in behavioural tests and regulated t... [more]
Cyanidin-3-glucoside Lipophilic Conjugates for Topical Application: Tuning the Antimicrobial Activities with Fatty Acid Chain Length
Hélder Oliveira, Patrícia Correia, Lucinda J. Bessa, Marta Guimarães, Paula Gameiro, Victor de Freitas, Nuno Mateus, Luís Cruz, Iva Fernandes
March 28, 2023 (v1)
Keywords: anthocyanins, antimicrobial, antioxidants, cosmetic, enzymatic activity, healthcare
Background: Natural anthocyanins present a low solubility in lipophilic media, which compromises their effective application in lipophilic systems. In this work, cyanidin-3-O-glucoside (Cy3glc) was esterified by the addition of fatty acids with increasing chain-lengths and a structure-activity relationship was performed towards the description of the best analog for skin-care applications. Methods: By enzymatic hemi-synthesis, it was possible to obtain 5 structurally related derivatives of cyanidin-3-O-glucoside with successive C2 increments in the aliphatic chain. The stability in hanks buffer and DMEM with or without FBS was followed by HPLC. The cytotoxicity against keratinocytes was evaluated by MTT assay. The antioxidant capacity was determined by using the fluorescent probe DCF-DA. The effect on enzyme activity was evaluated towards tyrosinase, collagenase, and elastase enzymes by colorimetric assays. MIC and MBC values were obtained against reference strains and against multidru... [more]
Classification and Analysis of Optimization Techniques for Integrated Energy Systems Utilizing Renewable Energy Sources: A Review for CHP and CCHP Systems
Mohammad Ali Bagherian, Kamyar Mehranzamir, Amin Beiranvand Pour, Shahabaldin Rezania, Elham Taghavi, Hadi Nabipour-Afrouzi, Mohammad Dalvi-Esfahani, Seyed Morteza Alizadeh
March 28, 2023 (v1)
Keywords: combined cooling, combined heat and power (CHP), evolutionary computing, heating and power (CCHP), integrated energy system (IES), thermoeconomic optimization
Energy generation and its utilization is bound to increase in the following years resulting in accelerating depletion of fossil fuels, and consequently, undeniable damages to our environment. Over the past decade, despite significant efforts in renewable energy realization and developments for electricity generation, carbon dioxide emissions have been increasing rapidly. This is due to the fact that there is a need to go beyond the power sector and target energy generation in an integrated manner. In this regard, energy systems integration is a concept that looks into how different energy systems, or forms, can connect together in order to provide value for consumers and producers. Cogeneration and trigeneration are the two most well established technologies that are capable of producing two or three different forms of energy simultaneously within a single system. Integrated energy systems make for a very strong proposition since it results in energy saving, fuel diversification, and s... [more]
Multiscale Characterization of Isotropic Pyrolytic Carbon Used for Mechanical Heart Valve Production
Gianpaolo Serino, Mattia Gusmini, Alberto Luigi Audenino, Giovanni Bergamasco, Ornella Ieropoli, Cristina Bignardi
March 28, 2023 (v1)
Subject: Materials
Keywords: deposition process, heart dysfunction, low temperature pyrolytic carbon, mechanical characterization, nanoindentation
Usage of pyrolytic carbon (PyC) to produce mechanical heart valves (MHVs) has led to heart valve replacement being a very successful procedure. Thus, the mechanical properties of employed materials for MHV production are fundamental to obtain the required characteristics of biocompatibility and wear resistance. In this study, two deposition methods of PyC were compared through a multiscale approach, performing three-point bending tests and nanoindentation tests. Adopted deposition processes produced materials that were slightly different. Significant differences were found at the characteristic scale lengths of the deposited layers. Setting changes of the deposition process permitted obtaining PyC characterized by a more uniform microstructure, conferring to the bulk material superior mechanical properties.
Thermal Stability of Ionic Liquids: Current Status and Prospects for Future Development
Chenqian Xu, Zhenmin Cheng
March 28, 2023 (v1)
Subject: Materials
Keywords: dicationic ionic liquid, ionic liquid, thermal decomposition kinetics, thermal stability
Ionic liquids (ILs) are the safest solvent in various high-temperature applications due to their non-flammable properties. In order to obtain their thermal stability properties, thermogravimetric analysis (TGA) is extensively used to analyze the kinetics of the thermal decomposition process. This review summarizes the different kinetics analysis methods and finds the isoconversional methods are superior to the Arrhenius methods in calculating the activation energy, and two tools—the compensation effect and master plots—are suggested for the calculation of the pre-exponential factor. With both parameters, the maximum operating temperature (MOT) can be calculated to predict the thermal stability in long-term runnings. The collection of thermal stability data of ILs with divergent cations and anions shows the structure of cations such as alkyl side chains, functional groups, and alkyl substituents will affect the thermal stability, but their influence is less than that of anions. To devel... [more]
Separation of Benzene-Cyclohexane Azeotropes Via Extractive Distillation Using Deep Eutectic Solvents as Entrainers
Fang Bai, Chao Hua, Jing Li
March 28, 2023 (v1)
Keywords: benzene, cyclohexane, deep eutectic solvents (DES), entrainer, extractive distillation
The separation of benzene and cyclohexane azeotrope is one of the most challenging processes in the petrochemical industry. In this paper, deep eutectic solvents (DES) were used as solvents for the separation of benzene and cyclohexane. DES1 (1:2 mix of tetrabutylammonium bromide (TBAB) and levulinic acid (LA)), DES2 (1:2 mix of TBAB and ethylene glycol (EG)) and DES3 (1:2 mix of ChCl (choline chloride) and LA) were used as entrainers, and vapor-liquid equilibrium (VLE) measurements at atmospheric pressure revealed that a DES comprised of a 2:1 ratio of LA and TBAB could break this azeotrope with relative volatility (αij) up to 4.763. Correlation index suggested that the NRTL modelling approach fitted the experimental data very well. Mechanism of extractive distillation gained from FT-IR revealed that with hydrogen bonding and π−π bond interactions between levulinic acid and benzene could be responsible for the ability of this entrainer to break the azeotrope.
Environmental Method for Synthesizing Amorphous Silica Oxide Nanoparticles from a Natural Material
Vahid Zarei, Mojtaba Mirzaasadi, Afshin Davarpanah, Alireza Nasiri, Majid Valizadeh, Mohammad Javad Sarbaz Hosseini
March 28, 2023 (v1)
Subject: Materials
Keywords: amorphous silica Nanoparticle, environmentally friendly short method, non-toxic, rice husks
Numerous studies have been performed on the generation of several silicon-based engineering materials that often have used chemical materials that have high risks for health and the safety of the environment. Generally, in the synthesis of Nano-silica, tetramethoxysilane, tetraethoxysilane, and tetraethyl orthosilicate (TEOS) are used as precursor materials; however, these materials are toxic and expensive for the production of Nano-silica. This paper presents an environmentally friendly short method (EFSM) with high efficiency for the synthesis of amorphous silica oxide Nanoparticles by using agricultural waste called rice husks (RHs). Use of the EFSM method as an alternative to the chemical methods would have the advantages of fast and simple operation, controllability, great pureness of the Nanoparticles, and low manufacturing cost. A Nanoparticles (NPs) evaluation was conducted with energy-dispersive spectroscopy (EDS), field emission scanning electron microscope (FESEM) and X-ray... [more]
Biomass Energy Technologies from Innovative Dairy Farming Systems
Wacław Romaniuk, Kamila Mazur, Kinga Borek, Andrzej Borusiewicz, Witold Jan Wardal, Sylwester Tabor, Maciej Kuboń
March 28, 2023 (v1)
Subject: Environment
Keywords: comprehensive manure management solutions, dairy cattle farming, feeding, maintenance system
Modern and innovative dairy cattle breeding technologies are highly dependent on the level of mechanization. This article presents modern solutions for dairy cattle breeding, in particular, for livestock buildings, in which longitudinal development is possible in accordance with the farm’s needs as well as with obtaining additional energy from biogas and post-ferment for granulated organic fertilizer. In the analysed technology for milk production, methane fermentation, biogas yield, and the possibility of fertilizer production in the form of granules are considered. The presented modular cattle breeding technology includes sustainable production, which is economic; environmentally friendly, with preconditions in the facility including animal welfare; and socially acceptable, resulting from a high level of mechanization, which ensures both comfortable working conditions and high milk quality. The presented production line is an integral part of the milk production process with the poss... [more]
Optimal Water Management in Agro-Industrial Districts: An Energy Hub’s Case Study in the Southeast of Spain
Jerónimo Ramos-Teodoro, Juan D. Gil, Lidia Roca, Francisco Rodríguez, Manuel Berenguel
March 28, 2023 (v1)
Keywords: deterministic optimization, economic dispatch, mixed-integer linear programming, Model Predictive Control, multi-energy systems, self-consumption
In this work, the optimal management of the water grid belonging to a pilot agro-industrial district, based on greenhouse cultivation, is analyzed. Different water supply plants are considered in the district, some of them using renewable energies as power sources, i.e., a solar thermal desalination plant and a nanofiltration facility powered up by a photovoltaic field. Moreover, the trade with the water public utility network is also taken into account. As demanding agents, a greenhouse and an office building are contemplated. Due to the different water necessities, demand profiles, and the heterogeneous nature of the different plants considered as supplier agents, the management of the whole plant is not trivial. In this way, an algorithm based on the energy hubs approach, which takes into account economic terms and the optimal use of the available resources in its formulation, is proposed for the pilot district with a cropping area of 616 m2. Simulation results are provided in order... [more]
Numerical Investigation of a Novel Plate-Fin Indirect Evaporative Cooling System Considering Condensation
Yuanyuan Zhou, Zhen Yan, Ming Gao, Qiumin Dai, Yanshun Yu
March 28, 2023 (v1)
Keywords: condensation, heat transfer, indirect evaporative cooling, mass transfer, thermoelectric cooling
An indirect evaporative cooling system combining with thermoelectric cooling technology (i.e., TIEC system) is proposed, in which a counter-flow plate-fin indirect evaporative cooler is inserted with thermoelectric cooling (i.e., TEC) modules. In hot and humid climate, condensation may occur on the dry channel surface of the cooler. For the TIEC system, with the aid of TEC technology, the surface temperature of the dry channel can be much lower than that of a traditional indirect evaporative cooler, thus, the condensation from the primary air is more likely to take place. A numerical model of this novel TIEC system is developed with specifically taking condensation from primary air into account. Detailed performance analysis of the TIEC system is carried out. Analytical results found that the condensation from primary air reduces the dew point effectiveness by up to 45.0% by weakening the sensible heat transfer but increases the coefficient of performance by up to 62.2% by increasing t... [more]
Temperature-Dependent Viscosity Model for Silicone Oil and Its Application in Viscous Dampers
Márk Venczel, Gabriella Bognár, Árpád Veress
March 28, 2023 (v1)
Keywords: Carreau–Yasuda viscosity model, Computational Fluid Dynamics, non-Newtonian fluid, rheology, silicone oil, viscous torsional vibration damper
Silicone fluids belong to the group of pseudoplastic non-Newtonian fluids with complex rheological characteristics. They are considered in basic and applied researches and in a wide range of industrial applications due to their favorable physical and thermal properties. One of their specific field of applications in the automotive industry is the working fluid of viscous torsional vibration dampers. For numerical studies in the design and development phase of this damping product, it is essential to have thorough rheological knowledge and mathematical description about the silicone oil viscosity. In the present work, adopted rheological measurement results conducted on polydimethylsiloxane manufactured by Wacker Chemie with initial viscosity of 1000 Pas (AK 1 000 000 STAB silicone oil) are processed. As a result of the parameter identification by nonlinear regression, the temperature-dependent parameter curves of the Carreau−Yasuda non-Newtonian viscosity model are generated. By implem... [more]
Exploration of Active Site-Directed Plasmin Inhibitors: Beyond Tranexamic Acid
Yuko Tsuda, Koushi Hidaka, Keiko Hojo, Yoshio Okada
March 28, 2023 (v1)
Subject: Biosystems
Keywords: active site-directed plasmin inhibitors, serine proteases, tranexamic acid
Plasmin (Plm), a trypsin-like serine protease, is responsible for fibrinolysis pathway and pathologic events, such as angiogenesis, tumor invasion, and metastasis, and alters the expression of cytokines. A growing body of data indicates that a Plm inhibitor is a potential candidate as an anti-inflammatory and anti-cancer agent. A class of active site-directed plasmin inhibitors containing tranexamic acid residue has been designed. As evidenced by docking studies, the inhibitor binds to the active site not to the lysine binding site (LBS) in plasmin, thus preventing plasmin from digesting the substrate. Further optimization of the series, concerning both activity and selectivity, led to the second generation of inhibitors. This review focuses on the Plm inhibitory activity-structure relationship of Plm inhibitors with the goal of realizing their design and clinical application.
On Numerical 2D P Colonies Modelling the Grey Wolf Optimization Algorithm
Daniel Valenta, Miroslav Langer
March 28, 2023 (v1)
Keywords: 2D P colonies, Algorithms, blackboard, data structures, Grey wolf optimization algorithm, P systems, Simulation
The 2D P colonies is a version of the P colonies with a two-dimensional environment designed for observing the behavior of the community of very simple agents living in the shared environment. Each agent is equipped with a set of programs consisting of a small number of simple rules. These programs allow the agent to act and move in the environment. The 2D P colonies have been shown to be suitable for the simulations of various (not only) multi-agent systems, and natural phenomena, like flash floods. The Grey wolf algorithm is the optimization-based algorithm inspired by social dynamics found in packs of grey wolves and by their ability to create hierarchies, in which every member has a clearly defined role, dynamically. In our previous papers, we extended the 2D P colony by the universal communication device, the blackboard. The blackboard allows for the agents to share various information, e.g., their position or the information about their surroundings. In this paper, we follow our... [more]
Failure Prognosis Based on Relevant Measurements Identification and Data-Driven Trend-Modeling: Application to a Fuel Cell System
Mohand Djeziri, Oussama Djedidi, Samir Benmoussa, Marc Bendahan, Jean-Luc Seguin
March 28, 2023 (v1)
Keywords: discrete state model, fuel-cell systems, health index identification, remaining useful life, trend modeling
Fuel cells are key elements in the transition to clean energy thanks to their neutral carbon footprint, as well as their great capacity for the generation of electrical energy by oxidizing hydrogen. However, these cells operate under straining conditions of temperature and humidity that favor degradation processes. Furthermore, the presence of hydrogen—a highly flammable gas—renders the assessment of their degradations and failures crucial to the safety of their use. This paper deals with the combination of physical knowledge and data analysis for the identification of health indices (HIs) that carry information on the degradation process of fuel cells. Then, a failure prognosis method is achieved through the trend modeling of the identified HI using a data-driven and updatable state model. Finally, the remaining useful life is predicted through the calculation of the times of crossing of the predicted HI and the failure threshold. The trend model is updated when the estimation error b... [more]
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