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Showing records 14298 to 14322 of 43292. [First] Page: 1 569 570 571 572 573 574 575 576 577 Last
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]
Validation of the Molar Flow Rates of Oil and Gas in Three-Phase Separators Using Aspen Hysys
Adeola Grace Olugbenga, Najah M. Al-Mhanna, Muibat Diekola Yahya, Eyitayo Amos Afolabi, Martins Kolade Ola
March 28, 2023 (v1)
Keywords: Aspen HYSYS, gas, molar flow, oil, Peng–Robinson model, separator
A three-phase separator is the first vessel encountered by well fluids. The application of separators has been of great value to the oil and gas industry. In order to generate the gas phase envelope that is applicable to the study of reservoir fluid and the selection of optimum operating conditions of separators, this research utilizes a specified reservoir fluid stream to simulate a three-phase separator executed in Aspen HYSYS. Subsequently, a comparative study of the effects of specified inlet operating conditions on the output of gas and oil streams was carried out. The results show that changing the inlet pressure of the separator from 1000 to 8000 kPa reduces the gas outlet flow from 1213 to 908.6 kg mol/h, while it increases the liquid flow rate from 374 to 838.0 kg mole/h. By changing the temperature of the separator feed stream from 13 to 83 °C, the gas outlet stream was raised from 707.4 to 1111 kg mol/h, while the liquid flow rate dropped from 1037.0 to 646.1 kg mol/h. It wa... [more]
Influence of Hanseniasporauvarum AS27 on Chemical and Sensorial Characteristics of Aglianico Wine
Bruno Testa, Francesca Coppola, Silvia Jane Lombardi, Massimo Iorizzo, Francesco Letizia, Massimo Di Renzo, Mariantonietta Succi, Patrizio Tremonte
March 28, 2023 (v1)
Subject: Biosystems
Keywords: aglianico wine, aroma compounds, Hanseniaspora uvarum, sensory evaluation, sequential inoculation
In this work was evaluated the effect of sequential inoculum of Hanseniaspora uvarum AS27 strain and a commercial Saccharomyces cerevisiae yeast on the physical−chemical and organoleptic features of Aglianico, a traditional red wine of Southern Italy. Four fermentation treatments on a pilot scale were performed. In fermentation treatment A, the alcoholic fermentation was spontaneously conducted by the indigenous yeasts present in grape must. In the fermentation treatments B and C were inoculated respectively S. cerevisiae FE and H. uvarum AS27 strains, as a single starter. The fermentation treatment D was initially inoculated with H. uvarum AS27, and S. cerevisiae strain was added after 72 h (sequential inoculation). Microbiological, physical−chemical parameters and sensory profiles of the wines have been defined. The results showed that the use of H. uvarum AS27, in sequential inoculum with S. cerevisiae FE, influenced the wine composition, enriching it in polyphenolic and volatile co... [more]
High Temperature Adsorption of SO2 on Mixed Oxides Derived from CaAl Hydrotalcite-Like Compounds
Hailin Wang, Run Hao, Meiping Gao, Zhongshen Zhang, Zhengping Hao
March 28, 2023 (v1)
Subject: Environment
Keywords: CaAlO, high temperature adsorption, hydrotalcite-like compounds, SO2
SO2 which is usually emitted at high temperature is one of the most important air pollutants. It is of great significance to develop high temperature SO2 adsorbent with high efficiency and low cost. In this work, a series of hydrotalcite-like compound-derived CaAlO and CaXAlO(X = Ce, Co) were prepared by coprecipitation and calcination method, and were employed as adsorbents for SO2 adsorption at high temperature (700 °C). The structure and surface properties of these adsorbents were characterized by XRD, Brunauer−Emmett−Teller (BET), Derivative thermogravimetric analysis (DTG) and CO2-TPD (temperature programmed desorption) measurement. Addition of a minor amount of Ce, Co (5 wt%) could significantly increase the number of weak alkalinity sites. CaO in CaCeAlO showed the best SO2 adsorption capacity of 1.34 g/g, which is two times higher than that of CaO in CaAlO (0.58 g/g).
mAb Production Modeling and Design Space Evaluation Including Glycosylation Process
Ou Yang, Marianthi Ierapetritou
March 28, 2023 (v1)
Keywords: dynamic kriging, feasibility analysis, glycosylation, kinetic modeling
Due to high demand, monoclonal antibodies (mAbs) production needs to be efficient, as well as maintaining a high product quality. Quality by design (QbD) via predictive process modeling greatly facilitates process understanding and can be used to adjust process parameters to further improve the unit operations. In this work, mechanistic and dynamic kriging models are developed to capture the protein productivity and glycan fractions under different temperatures and pH levels. The design of experiments is used to generate input and output data for model training. The dynamic kriging model shows good performance in capturing the dynamic profiles of cell cultures and glycosylation using only limited input data. The developed model is further used for feasibility analysis, and successfully identifies the operating design space, maintaining high productivity and guaranteed product quality.
Implementation of Different PV Forecast Approaches in a MultiGood MicroGrid: Modeling and Experimental Results
Simone Polimeni, Alfredo Nespoli, Sonia Leva, Gianluca Valenti, Giampaolo Manzolini
March 28, 2023 (v1)
Subject: Optimization
Keywords: energy management system, microgrid, mixed-integer linear programming, photovoltaic (PV) forecast, photovoltaic energy
Microgrids represent a flexible way to integrate renewable energy sources with programmable generators and storage systems. In this regard, a synergic integration of those sources is crucial to minimize the operating cost of the microgrid by efficient storage management and generation scheduling. The forecasts of renewable generation can be used to attain optimal management of the controllable units by predictive optimization algorithms. This paper introduces the implementation of a two-layer hierarchical energy management system for islanded photovoltaic microgrids. The first layer evaluates the optimal unit commitment, according to the photovoltaic forecasts, while the second layer deals with the power-sharing in real time, following as close as possible the daily schedule provided by the upper layer while balancing the forecast errors. The energy management system is experimentally tested at the Multi-Good MicroGrid Laboratory under three different photovoltaic forecast models: (i)... [more]
Modelling Cell Metabolism: A Review on Constraint-Based Steady-State and Kinetic Approaches
Mohammadreza Yasemi, Mario Jolicoeur
March 28, 2023 (v1)
Subject: Biosystems
Keywords: constraint-based modelling approach, dynamic metabolic flux analysis, Gibbs free energy, kinetic modelling, metabolic control analysis, metabolic flux regulation, metabolic model parameterization, metabolic network, metabolic network structure, thermodynamic constraints
Studying cell metabolism serves a plethora of objectives such as the enhancement of bioprocess performance, and advancement in the understanding of cell biology, of drug target discovery, and in metabolic therapy. Remarkable successes in these fields emerged from heuristics approaches, for instance, with the introduction of effective strategies for genetic modifications, drug developments and optimization of bioprocess management. However, heuristics approaches have showed significant shortcomings, such as to describe regulation of metabolic pathways and to extrapolate experimental conditions. In the specific case of bioprocess management, such shortcomings limit their capacity to increase product quality, while maintaining desirable productivity and reproducibility levels. For instance, since heuristics approaches are not capable of prediction of the cellular functions under varying experimental conditions, they may lead to sub-optimal processes. Also, such approaches used for bioproc... [more]
Optimization Control on the Mixed Free-Surface-Pressurized Flow in a Hydropower Station
Xinlong Wang, Honggang Fan, Bing Liu
March 28, 2023 (v1)
Keywords: characteristic implicit method, optimization control, relative roughness, the mixed free-surface-pressurized flow, vent holes
The mixed free-surface-pressurized flow in the tailrace tunnel of a hydropower station has a great impact on the pressure, velocity, and operation stability of the power station. In the present work, a characteristic implicit method based on the upwind differencing and implicit finite difference scheme is used to solve the mixed free-surface-pressurized flow. The results of the characteristic implicit method agree well with the experimental results, which validates the accuracy of the method. Four factors that influence the amplitude of pressure fluctuation are analyzed and optimized, and the results show that the relative roughness can influence the maximum pressure in the tailrace tunnel. Additionally, the maximum pressure decreases with the increase of the tunnel’s relative roughness. When the surface relative roughness increases from 0.010 to 0.018, the maximum pressure can decrease by 4.33%. The maximum pressure in the tailrace tunnel can be effectively restrained by setting vent... [more]
Skin Moisturizing Effects of a Microneedle Patch Containing Hyaluronic Acid and Lonicerae flos
Sang-Kuk Han, Seung-Jun Lee, Hun-Yong Ha
March 28, 2023 (v1)
Subject: Materials
Keywords: clinical trial, hyaluronic acid, Lonicerae flos, microneedle patch, moisturizing
The utilization of cosmetic raw materials for medicinal purposes in a microneedle patch containing hyaluronic acid (HA) and Lonicerae flos ethanol extract (LEE) has increased based on their eco-friendly characteristics. The moisturizing effects of this microneedle patch were assessed on the forearms of 20 female participants, and our results showed an increase between 29.60% and 88.54% in skin moisture content at the same time points relative to the untreated group. Apart from confirming the safety of HA and Lonicerae flos, our findings may also promote the use of HA and medicinal herbs in relevant industries, indicating their potential as raw ingredients for the development of cosmetic products and topical dermatological drugs. The results suggested that HA, Lonicerae flos, and other combinations of chemical and natural products based on traditional oriental medicine could beneficially affect skin health.
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