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Records with Subject: Materials
2920. LAPSE:2023.8523
Petroleum Systems Analysis of Turbidite Reservoirs in Rift and Passive Margin Atlantic Basins (Brazil and Portugal)
February 24, 2023 (v1)
Subject: Materials
Keywords: dynamic elements, petroleum systems, sedimentary basins, static elements, turbiditic reservoirs
Due to the success of oil and gas production, turbidites have become exploratory targets over the past 40 years in the rift and passive margin basins in the North and South Atlantic. The turbiditic reservoirs in rift and passive margin settings of Atlantic sedimentary basins located in Brazil (Campos Basin) and Portugal (Lusitanian Basin) represent potential economic units for the hydrocarbon exploration. However, despite being considered analogous reservoirs, these units present distinct potentials for the accumulation of hydrocarbons. In this context, the work presented discusses the results obtained from the analysis of static (source rock, reservoir rock, seal and trap) and dynamic elements (migration, tectonic, diagenetic and thermal processes) of both studied petroleum systems, using geological, seismic, well, geochemical and petrographic data. The developed methodology of multiscalar characterization of the two petroleum systems was successful, leading to a specific classificati... [more]
2921. LAPSE:2023.8517
Historical Review of Advancements in Insulated Cross-Arm Technology
February 24, 2023 (v1)
Subject: Materials
Keywords: composite, cross-arm, transmission lines
High-voltage transmission technology has advanced quickly with the overall development and increased use of renewable energy. More demands on the insulating system are made when high-voltage power systems evolve. One of the significant factors is the sharp rise in population density, which led to the high demand for electricity. Right-of-way infringement is a problem that frequently occurs these days. Transmission is done over a rated capacity; as a result, the transmission line heats up, the insulation ages, and the electric field becomes distorted. The insulating system is prone to fail too soon when the operating voltage inverses or when there is a significant temperature differential. Environmentally friendly insulating materials have received much attention recently. A synergistic optimisation of heat resistance properties, mechanical properties, and dielectric properties must be accomplished before these materials can be used in high-voltage transmission systems. They must also w... [more]
2922. LAPSE:2023.8499
Investigation on the Melting Performance of a Phase Change Material Based on a Shell-and-Tube Thermal Energy Storage Unit with a Rectangular Fin Configuration
February 24, 2023 (v1)
Subject: Materials
Keywords: melting performance, phase change material, rectangular fin configuration, shell-and-tube thermal energy storage unit
A case study on the melting performance of a shell-and-tube phase change material (PCM) thermal energy storage unit with a novel rectangular fin configuration is conducted in this paper. Paraffin wax and circulated water are employed as the PCM and heat transfer fluid (HTF), respectively. It can be observed that the melting performance could be significantly improved by using rectangular fins. Melting photographs demonstrate that the melting of the PCM is firstly dominated by heat conduction; then, the melting rate is improved further due to natural convection. Moreover, the results illustrate that the influence of the inlet HTF temperature on the melting performance is significantly greater than that of the inlet HTF flow rate. The liquid fraction of paraffin wax in the PCM unit with a higher inlet HTF temperature is always higher than that with a lower inlet HTF temperature at the same time. The total charging time is reduced by 62.38% and the average charging rate is increased by 16... [more]
2923. LAPSE:2023.8486
Form of the Occurrence of Aluminium in Municipal Solid Waste Incineration Residue—Even Hydrogen Is Lost
February 24, 2023 (v1)
Subject: Materials
Keywords: aluminium recovery, bottom ash, hydrogen generation, municipal solid waste incineration
In the bottom ash (BA) of municipal solid waste incineration, the content of iron and aluminum is relatively high. The efficiency of eddy current extraction of non-ferrous metals (including aluminium) routinely used in incineration plants is limited. The determination of the form of occurrence of aluminium or aluminium-rich components in BA is important in terms of its recovery or utilisation. BA from a newly built incineration plant in Poland was analysed using chemical analysis, X-ray diffraction, optical microscopy, and scanning electron microscopy with chemical microanalysis. Samples of water-quenched BA were analysed. For comparison, a non-quenched sample (collected above a water tank) was analysed. The obtained results indicate that aluminium-rich components in BA are present in both the melt phase and quench phase. In the melt phase (glassy material), the content of aluminium is low (usually below 2 wt%). Aluminium-rich components present in glass, inherited after aluminium prod... [more]
2924. LAPSE:2023.8485
Experimental Study of the Feasibility of In-Situ Hydrogen Generation from Gas Reservoir
February 24, 2023 (v1)
Subject: Materials
Keywords: autothermal reforming (ATR), depleted gas reservoir, hydrogen generation, partial oxidation of methane (POM), pseudo dynamic
Due to there is no better way to exploit depleted gas reservoirs, and hydrogen can generate from natural gas combustion. In this paper, the possibility of in-situ hydrogen generation in air injected gas reservoirs was determined through pseudo dynamic experiments. The study indicated that higher temperature and steam/methane ratio can generate more hydrogen, and the temperature should not be lower than 600 °C within gas reservoirs. The debris has positive catalysis for hydrogen generation. The maximum mole fraction of hydrogen was 26.63% at 600 °C.
2925. LAPSE:2023.8481
Experimental Thermodynamic Characterization of the Chalcopyrite-Based Compounds in the Ag−In−Te System for a Potential Thermoelectric Application
February 24, 2023 (v1)
Subject: Materials
Keywords: Ag-based compounds, EMF method, Gibbs free energy, Phase Equilibria, thermodynamic properties, thermoelectric materials
The equilibrium concentration space of the Ag−In−Te system in the part AgInTe2−Te−In2Te3 was studied through the modified solid-state electromotive force (EMF) method by dividing In2Te3−In2Te5−Ag3In97Te147 (I), In2Te5−Te−Ag3In97Te147 (II), Ag3In97Te147−Te−AgIn5Te8 (III), AgIn5Te8−Te−AgIn3Te5 (IV), and AgIn3Te5−Te−AgInTe2 (V), into separate phase regions at T ≤ 500 K. The formation of a thermodynamically stable combination of the binary and ternary phases in the (I)−(V) phase regions from a metastable phase mixture of substances was carried out at T ≤ 500 K in the R(Ag+) part of the positive electrode (PE) of the galvanic cells (GCs) of the structure: (−) C |∙| Ag |∙| SE |∙| R(Ag+) |∙| PE |∙| C (+), where C is the graphite (inert electrode), SE is the solid-state electrolyte (Ag3GeS3Br glass), and Ag is the left (negative) electrode. The Ag+ ions in the R(Ag+) region functioned as small nucleation centers for the formation of the stable phases. The spatial position of the (I)−(V) phase... [more]
2926. LAPSE:2023.8475
Hammer Impact-Driven Power Generator Using Buzzer-Type Piezoelectric Energy Converter for Wind Power Generator Applications
February 24, 2023 (v1)
Subject: Materials
Keywords: energy harvesting, piezoelectric, piezoelectric buzzer, wind power
A novel hammer-impact-driven power generator that uses a buzzer-type piezoelectric energy converter (BPEC) for wind-power-generator applications was designed, and the dynamic motions and output characteristics were analyzed. As the active material, Sm0.025-Pb0.9625[(Mg1/3Nb2/3)0.71Ti0.29]O3 (Sm-PMN-PT)ceramic was used; this material has a high piezoelectric charge constant of 1100 pC/N and an electromechanical coupling factor of 58%. A rotational impeller triggered an impact between one end of the bar-type hammer, and, thereby, impact energy transferred to the BPECs. The manufactured power generator was tested from 50 RPM to 250 RPM, using the handmade evaluation system; it was able to operate with small impact force and greatly improved output performance as rotation speed increased. The maximum output of the generator was 10.4 W at a load resistance of 500 Ω and rotation speed of 250 RPM. For improvement of the output characteristics, the generators were arranged such that they could... [more]
2927. LAPSE:2023.8446
Recent Insights into Low-Surface-Area Catalysts for Hydrogen Production from Ammonia
February 24, 2023 (v1)
Subject: Materials
Keywords: ammonia decomposition, catalysts, cobalt, hydrogen production, low surface area, nickel, novel support, ruthenium
A potential method of storing and transporting hydrogen safely in a cost-effective and practical way involves the utilization of molecules that contain hydrogen in their structure such as ammonia. Because of its high hydrogen content and carbon-free molecular structure, as well as the maturity of related technology (easy liquefaction), ammonia has gained attention as a “hydrogen carrier” for the generation of energy. Unfortunately, hydrogen production from ammonia requires an efficient catalyst to achieve high conversion at low reaction temperatures. Recently, very attractive results have been obtained with low-surface-area materials. This review paper is focused on summarizing and comparing recent advances in novel, economic and active catalysts for this reaction, paying particular attention to materials with low surface area such as silicon carbide (SiC) and perovskites (ABO3 structure). The effects of the supports, the active phase and the addition of promoters in such low-porosity... [more]
2928. LAPSE:2023.8442
Gasification of Solid Recovered Fuels with Variable Fractions of Polymeric Materials
February 24, 2023 (v1)
Subject: Materials
Keywords: construction and demolition waste, gasification, polymeric waste, solid recovered fuel
Gasification is a promising thermochemical technology used to convert waste materials into energy with the introduction of low amounts of an oxidant agent, therefore producing an environmental impact that is lower when compared to incineration and landfilling. Moreover, gasification allows a sustainable management of wastes and reduces the use of fossil fuels responsible for the increment of greenhouse gases. This work aimed to perform gasification tests with solid recovered fuels (SRF) containing organic fractions mainly retrieved from construction and demolition wastes to assess the potential for energy conversion. Tests were conducted in a pilot-scale downdraft gasifier (maximum feedstock input of 22 kg/h) at c.a. 800 °C, using SRF samples containing different proportions of polymeric wastes ranging between 0 and 20 wt %. Gas and chars obtained as by-products were analysed to evaluate their properties and to establish valid pathways for their valorisation. The addition of polymeric... [more]
2929. LAPSE:2023.8420
A Mini-Review on CO2 Photoreduction by MgAl-LDH Based Materials
February 24, 2023 (v1)
Subject: Materials
Keywords: carbon oxide, MgAl-LDH, modification strategy, photoreduction
In recent years, the rapid consumption of fossil fuels has brought about the energy crisis and excess CO2 emission, causing a series of environmental problems. Photocatalytic CO2 reduction technology can realize CO2 emission reduction and fuel regeneration, which alleviates the energy crisis and environmental problems. As the most widely used LDH material in commercial application, MgAl-layered double hydroxide (MgAl-LDH) already dominates large-scale production lines and has the potential to be popularized in CO2 photoreduction. The adjustable component, excellent CO2 adsorption performance, and unique layer structure of MgAl-LDH bring specific advantages in CO2 photoreduction. This review briefly introduces the theory and reaction process of CO2 photocatalytic reduction, and summarizes the features and drawbacks of MgAl-LDH. The modification strategies to overcome the drawbacks and improve photocatalytic activity for MgAl-LDH are elaborated in detail and the development perspectives... [more]
2930. LAPSE:2023.8405
Thermoelectric Micro-Scale Generation by Carbonaceous Devices
February 24, 2023 (v1)
Subject: Materials
Keywords: combustion, microgeneration, Seebeck effect, solid fuels
The paper reports on research focused on the use of largely available carbonaceous materials, such as graphite, carbon black and chars, as thermoelectric materials for micro-generation at high temperature. The key feature is the possibility to ignite the thermoelectric device to self-sustain electric generation. The results of the tests performed with such materials, under both cold and hot conditions, showed that a significant change of the electromotive force, with absolute increase up to three orders of magnitude, occurred under hot conditions with flame irradiation, achieving measured values of electromotive force up to 55 mV, in the best case. Monoliths based on biomass chars and covered with a layer of gunpowder gave rise to similar variation of the Seebeck coefficient, as the case of the flame exposed samples. This result confirms the basic idea of the investigation and the possibility of generating an electrical peak in a self-sufficient combustion thermoelectric device with po... [more]
2931. LAPSE:2023.8401
Hard Carbon Reprising Porous Morphology Derived from Coconut Sheath for Sodium-Ion Battery
February 24, 2023 (v1)
Subject: Materials
Keywords: anode material, coconut sheath, hard carbon, pyrolysis process, sodium-ion batteries
Seeking effective energy technology has become a herculean task in today’s world. Sodium-ion batteries play a vital role in the present energy tech market due to their entrancing electrochemical properties and this work is a breakthrough for developing sodium-ion batteries. As per recent reports, the preparation of anode materials seems to be very tedious in the realm of sodium-ion batteries. To remedy these issues, this work enlightens the preparation of hard carbon (HC) derived from coconut sheath (CS) by a pyrolysis process with different activating agents (KOH, NaOH, ZnCl2) and employed as an anode material for Sodium-ion batteries (SIBs). The prepared anode material was characterized for its thermal, structural, functional, morphological, and electrochemical properties. Additionally, the surface area and pore diameter of the as-prepared anode material was studied by nitrogen adsorption and desorption isotherm methods. The coconut sheath-derived hard carbon (CSHC) anode material de... [more]
2932. LAPSE:2023.8372
ESG Assessment from the Perspective of the Management Board and Trade Unions on the Example of the Opole Power Plant
February 24, 2023 (v1)
Subject: Materials
Keywords: ESG, management board, power plant, survey research, trade unions
The Opole Power Plant is part of the PGE group (Polish Energy Group), the largest power company in Poland. It produces electricity from coal combustion, which means that ESG (environmental, social and corporate governance) policy should be one of the power plant’s strategic priorities. The article focuses on evaluating the ESG activities implemented by the power plant and their relation to the standards set at the corporation. The article’s primary hypothesis is that ESG activities are a significant element of the power plant’s strategy, with most of them determined by policies undertaken at the level of the PGE Group as a whole. The secondary hypotheses assume that trade union representatives attach greater importance (than management) to the social elements of ESG (H2) and that individual management representatives rate higher regarding the importance of those ESG areas for which they are personally responsible (H3). The research method used in the article consists of interviews cond... [more]
2933. LAPSE:2023.8354
Analysis of Electromagnetic−Mechanical Characteristics according to Shaft Materials of Permanent Magnet Synchronous Motor
February 24, 2023 (v1)
Subject: Materials
Keywords: electromagnetic–mechanical characteristics, permanent magnet synchronous motor, shaft materials, synchronous inductance
In this paper, an analysis of electromagnetic−mechanical characteristics according to the shaft materials of a permanent magnet synchronous motor was performed. In general, the shaft of an electric motor rotating at high speed uses various materials, considering the mechanical rigidity and electromagnetic characteristics. However, because the material of the shaft has a significant influence on the electromagnetic performance according to the characteristics of the non-magnetic and magnetic materials, electromagnetic characteristics analysis was performed according to the material of the shaft. In addition, because the machine rotating at a high speed entails mechanical problems owing to the centrifugal force, the mechanical stability was secured through critical speed characteristic analysis according to each material after performing the von Mises stress analysis of the permanent magnet and sleeve.
2934. LAPSE:2023.8349
Mathematical Model of Shale Oil Seepage at Micro-Nano Pore Scale
February 24, 2023 (v1)
Subject: Materials
Keywords: mechanism characterization, micro-nano pore, nonlinear seepage, shale oil, two-fluid model
Due to the unclear seepage mechanism for shale oil, it is hard to establish a reasonable mathematical model to describe the flowing law. In this study, a real shale pore structure was reconstructed with CT scanning and a numerical model of fluid flowing in the real shale pore is developed with COMSOL, based on the boundary slip at the micro-nano pore scale to study the causes of nonlinear seepage. A two-fluid model is employed to establish a simple mathematical model to describe the relationship between the flow rate and the pressure gradient using the effective slip length to account for the influence of pore structure and true slip, and the established model is verified with experimental data coming from Jiyang shale oil. The results indicated that the pore structure greatly affected the shape of the seepage curve. With the increase in displacement pressure, the percentage of fluid involved in the flow increased until it became stable, showing a changing trend from nonlinearity to li... [more]
2935. LAPSE:2023.8348
Impact of NaOH on the Hydrothermal Oxidation of Guaiacol for the Production of Value-Added Products
February 24, 2023 (v1)
Subject: Materials
Keywords: acetic acid, formic acid, guaiacol, hydrothermal oxidation, NaOH
In this study, the impact of NaOH on the hydrothermal oxidation of guaiacol was investigated. It was found that NaOH significantly accelerated the production of formic acid and acetic acid with H2O2 or CuO as the oxidant. With the strong oxidant, H2O2, the highest acetic acid yield (15.73%) and formic acid (5.64%) were obtained at 300 °C for 90 s with NaOH 1.0 mol·L−1 and a 100% H2O2 oxygen supply. In comparison, with CuO as the oxidant, the highest values of acetic acid (13.42%) and formic acid (4.21%) were acquired at 250 °C for 6 h with NaOH 1.0 mol·L−1. Formic acid and acetic acid were generated through the oxidation of intermediates, such as levulinic acid, fumaric acid, maleic acid, etc. These results demonstrated that NaOH catalytic hydrothermal oxidation has potential for the production of value-added chemicals from biomass materials. When CuO is used as the oxidant, this process could also be used as a green method for copper smelting along with the utilization of lignin bioma... [more]
2936. LAPSE:2023.8322
Improving the Single-Slope Solar Still Performance Using Solar Air Heater with Phase Change Materials
February 24, 2023 (v1)
Subject: Materials
Keywords: Exergy, hourly output, latent heat, PCM, solar energy, solar still
This communication discusses the energy, exergy, and economic feasibility of novel heat storage based on a single-slope solar still coupled with a solar air heater (SAH). The analysis was conducted on three different solar stills, i.e., a single-slope solar still (SSSS), single-slope solar still with latent heat storage, and a single-slope solar still with latent heat storage coupled with a solar air heater. The performance evaluation of all types of solar still has been compared to evaluate the best-performing solar still. Paraffin wax as a phase change material (PCM) has been used at the bottom of the solar still to provide proper thermal storage. The experiments were conducted on different depths, i.e., 3 cm, 6 cm, 9 cm, 12 cm, and 15 cm. The efficiency of a single-slope solar still with PCM and SAH was 65.58% higher than a conventional solar still. The average exergy efficiency of a single-slope solar still with latent heat storage coupled with a solar air heater is 83.19% higher t... [more]
2937. LAPSE:2023.8316
Chromium-Coated Zirconium Cladding Neutronics Impact for APR-1400 Reactor Core
February 24, 2023 (v1)
Subject: Materials
Keywords: accident-tolerant fuel, chromium coating, nuclear fuel, PWR
The accident-tolerant fuel concept involves replacing the conventional cladding system (zirconium) with a new material or coating that has specific thermomechanical properties. The aim of this study is to evaluate the neutronics performance of a chromium coating concept and design solutions. A Zircaloy−uranium fuel system (Zr−U) is currently used as a standard fuel system in pressurized water reactors around the world. This investigation presents the benefits of utilizing an alternative cladding material such as chromium coating and the effects on the thermal neutron parameters of the way in which the chromium coating is introduced in the reactor fuel. Among these significant benefits is an increase in the reactor fuel’s thermal conductivity, which improves reactor safety. Two types of fuel-cladding systems were investigated: Zircaloy−uranium (Zr−U) and Zircaloy−chromium (Zr−Cr−U) coating fuel systems. Neutronics analysis evaluations were performed for the selected fuel assemblies and... [more]
2938. LAPSE:2023.8299
Effect of Magnetic Properties of Magnetic Composite Tapes on Motor Losses
February 24, 2023 (v1)
Subject: Materials
Keywords: alternating current copper loss, drone, magnetic composite material, magnetic tape, outer rotor motor, winding
Alternating current (AC) copper losses in motors increase with carrier frequency of the pulse width modulation (PWM) and are further increased by leakage flux of the permanent magnet. Therefore, AC copper losses increase with motor speed. Conventional techniques for reducing AC copper losses tend to increase other losses. In this paper, AC copper loss was reduced by wrapping a magnetic tape made of a magnetic composite material around the winding. This method controlled the flux path through the winding. Magnetic composite materials are mixtures of magnetic powders and liquid resins whose magnetic properties can be manipulated by changing the combination and other factors. When Fe−Si−Al magnetic tape was wrapped around the winding, the AC copper loss was reduced by 40%. The loss was further reduced by optimizing the magnetic properties of the magnetic composite material. The AC copper loss was maximally reduced when the specific permeability was 100 and the saturation flux density was... [more]
2939. LAPSE:2023.8291
Safety Analysis on the Heating Surfaces in the 660 MW Ultra-Supercritical CFB Boiler under Sudden Electricity Failure
February 24, 2023 (v1)
Subject: Materials
Keywords: accident analysis, electricity failure, superheater, ultra-supercritical CFB, water wall
Ultra-supercritical circulating fluidized bed (CFB) boilers are taking up an increasing proportion of the CFB boiler fleet in China, making the safety concern about the heating surfaces in this type of boilers under sudden electricity failure draw more and more attention from the industry. For the time being, however, few studies have made efforts to resolve this concern. Given this, the physical process in a 660 MW ultra-supercritical boiler during the electricity failure accident was precited with a comprehensive model composed of mass and energy conservation equations in this work. The tube temperature of the boiler components with the highest safety risk, i.e., the water wall and a superheater, was obtained to evaluate the safety of the heating surfaces. The results revealed that the tube temperature (about 516 °C and 544 °C) would be obviously lower than the maximum permissible temperature of the tube material (600 °C and 630 °C) even when electricity could be restored at the powe... [more]
2940. LAPSE:2023.8286
Analysis of Using Soot Application in the Processing of Zinc-Bearing Waste Materials
February 24, 2023 (v1)
Subject: Materials
Keywords: coal-bearing materials, dust explosion, metallurgical waste, pyrometallurgical technologies, recycling
In metallurgical processes, coke is used, among other materials, in order to implement the process of removing zinc from waste by reduction and evaporation. Due to the implemented de-carbonization policy, we are dealing with an increase in costs and decreasing availability of coke, which leads to an intensive search for other possibilities for conducting the process, which may generate a fire and explosion hazard in the technological process. This article analyzes the possibility of using soot in the process of reducing the zinc content in deposited metallurgical waste, taking into account the issue of fire and explosion safety. The results of the research proved the possibility of the safe use of the reductor, which is soot and anthracite, as a material replacing coke in pyrometallurgical processes.
2941. LAPSE:2023.8280
A Systematic Approach to Thermochemical Treatment of Municipal Household Solid Waste into Valuable Products: Analysis of Routes, Gravimetric Analysis, Pre-Treatment of Solid Mixtures, Thermochemical Processes, and Characterization of Bio-Oils and Bio-Adso
February 24, 2023 (v1)
Subject: Materials
Keywords: bio-char characterization, bio-oil: liquid hydrocarbons, MHSW, organic fraction from MHSW, thermal processing
This work aims to investigate the effect of process temperature and catalyst content by pyrolysis and thermal catalytic cracking of (organic matter + paper) fraction from municipal household solid waste (MHSW) on the yields of reaction products (bio-oil, bio-char, H2O, and gas), acid value, chemical composition of bio-oils, and characterization of bio-chars in laboratory scale. The collecting sectors of MHSW in the municipality of Belém-Pará-Brazil were chosen based on geographic and socio-economic database. The MHSW collected and transported to the segregation area. The gravimetric analysis of MHSW was carried out and the fractions (Paper, Cardboard, Tetra Pack, Hard Plastic, Soft Plastic, Metal, Glass, Organic Matter, and Inert) were separated. The selected organic matter and paper were submitted to pre-treatment of crushing, drying, and sieving. The experiments carried out at 400, 450, and 475 °C and 1.0 atmosphere, and at 475 °C and 1.0 atmosphere, using 5.0, 10.0, and 15.0% (wt.)... [more]
2942. LAPSE:2023.8277
Thermal Radiation Energy Performance on Stagnation-Point Flow in the Presence of Base Fluids Ethylene Glycol and Water over Stretching Sheet with Slip Boundary Condition
February 24, 2023 (v1)
Subject: Materials
Keywords: Al2O3, nanofluids, shooting method, slip boundary condition, stagnation-point flow, stretching sheet, γ-Al2O3
Nanoparticles are useful in improving the efficiency of convective heat transfer. The current study addresses this gap by making use of an analogy between Al2O3 and γ-Al2O3 nanoparticles in various base fluids across a stretched sheet conjunction with f. Base fluids include ethylene glycol and water. We address, for the first time, the stagnation-point flow of a boundary layer of γ-Al2O3 nanofluid over a stretched sheet with slip boundary condition. Al2O3 nanofluids employ Brinkman viscosity and Maxwell’s thermal conductivity models with thermal radiations, whereas γ-Al2O3 nanofluids use viscosity and thermal conductivity models generated from experimental data. For the boundary layer, the motion equation was solved numerically using the fourth-order Runge−Kutta method and the shooting approach. Plots of the velocity profile, temperature profile, skin friction coefficient and reduced Nusselt number are shown. Simultaneous exposure of the identical nanoparticles to water and ethylene gl... [more]
2943. LAPSE:2023.8270
Recent Advances in Energy Harvesting from the Human Body for Biomedical Applications
February 24, 2023 (v1)
Subject: Materials
Keywords: bioelectronics, energy harvesting, implantable electronics, wearables
Energy harvesters serve as continuous and long-lasting sources of energy that can be integrated into wearable and implantable sensors and biomedical devices. This review paper presents the current progress, the challenges, the advantages, the disadvantages and the future trends of energy harvesters which can harvest energy from various sources from the human body. The most used types of energy are chemical; thermal and biomechanical and each group is represented by several nano-generators. Chemical energy can be harvested with a help of microbial and enzymatic biofuel cells, thermal energy is collected via thermal and pyroelectric nano-generators, biomechanical energy can be scavenged with piezoelectric and triboelectric materials, electromagnetic and electrostatic generators and photovoltaic effect allows scavenging of light energy. Their operating principles, power ratings, features, materials, and designs are presented. There are different ways of extracting the maximum energy and c... [more]
2944. LAPSE:2023.8259
Impact of Geometry on a Thermal-Energy Storage Finned Tube during the Discharging Process
February 24, 2023 (v1)
Subject: Materials
Keywords: ANSYS FLUENT, finned tube, one-dimensional Stefan problem, phase change materials, solidification and melting, thermal-energy storage
This work focused on the modelling of latent heat thermal energy storage systems. The mathematical modelling of a melting and solidification process has time-dependent boundary conditions because the interface between solid and liquid phases is a moving boundary. The heat transfer analysis needs the interface position over time to predict the temperature inside the liquid and the solid regions. This work started by solving the classical two-phase (one-dimensional) Stefan problem through a Matlab implementation of the analytical model. The same physical problem was numerically simulated using ANSYS FLUENT, and the good match of analytical and numerical results validated the numerical model, which was used for a more interesting problem: comparing three different latent heat TES configurations during the discharging process to evaluate the most efficient in terms of maximum average discharging power. The three axial heat conduction structures changed only for the fin shape (rectangular,... [more]
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