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Hydrogen is currently considered to be the best clean energy to replace fossil fuels, so hydrogen leak detection is crucial. The current research field of hydrogen sensors focuses on the discovery and optimization of sensitive materials. ZnFe 2 O 4 powder is prepared by the sol-gel method and sintered at different temperatures. The effects of sintering temperature on electrode morphology and hydrogen sensing performance are investigated. The sensitivity reaches a maximum value of −101.32 mV/decade at the sintering temperature of 1100 °C. The sensor has different sensing performance at different operating temperatures. It has the best response value and sensitivity at 450 °C, and the best response/recovery rate and response curve stability at 550 °C. The sensor responds and recovers in seconds. The material has good H 2 selectivity and is suitable for potentiometric hydrogen sensors. CO, NH 3 , and CH 4 have less effect on the response signal and exhibit good long-term stability. • Spinel ferrite is first used as an H 2 detection electrode for potentiometric sensors. • ZnFe 2 O 4 has high response value and sensitivity to hydrogen gas. • ZnFe 2 O 4 has a low detection limit and fast response/recovery rate for hydrogen gas. [ABSTRACT FROM AUTHOR]

Sensors utilizing mesoporous materials have garnered significant interest; however, they are primarily designed for detecting a single analyte. In this study, we successfully synthesized a three-dimensional (3D) hollow mesoporous α-Fe 2 O 3 using a nanocasting process for the purpose of sensing LPG and humidity. The α-Fe 2 O 3 obtained in this study maintained the cubic framework structure of MCM-48, demonstrating a mesoporous and hollow architecture. The Liquified Petroleum Gas (LPG) sensing characteristics of mesoporous α-Fe 2 O 3 were examined at different operating temperatures (170–210 °C). The gas sensing response was optimized 99.3 % at 190 °C and the response/recovery time comes out to be 11.79 s & 0.84 s respectively. The humidity sensor's traits were evaluated at room temperature, with relative humidity (RH%) ranging from 11 % to 98 %, using mesoporous α- Fe 2 O 3. The response/recovery time of mesoporous α-Fe 2 O 3 as a humidity sensor comes out to be 6.3 s & 7.2 s respectively. The highly sensitive nature of the sensor along with negligible hysteresis, excellent repeatability and considerable stability for 30 days makes it a promisable candidate for real-time subtle respiration monitoring. Meanwhile, mesoporous α-Fe 2 O 3 humidity sensor is also utilized for evaluation of sleep hypopnea-apnea syndrome. [ABSTRACT FROM AUTHOR]

Abstract The most rapidly expanding type of solar cells are the Perovskite Solar Cells (PSCs), because of its high device performance, ease of synthesis, high open-circuit voltage, and affordability. Despite these advantages, the development of perovskite-based solar cells continues to be impeded by the issues with perovskite stability and the utilization of the hazardous heavy element lead (Pb). The study emphasizes on the bifacial structure that maintains the conventional absorber layer and electron transport layer (ETL) in the optimized PSC structure. This study employs SCAPS software for device simulation to comprehensively analyze how various parameters affect the performance of solar cells. Additionally, doping concentration variation in both ETL and HTL are explored. The simulation reveals that changing device structure from monofacial to bifacial significantly influences PSC performance, demonstrating that optimizing individual layers effectively enhances overall solar cell performance. The optimized structure achieves impressive PSC performance metrics through parametric analysis, such as voltage (VOC) of 1.18 V, fill factor (FF) of 82.24%, current density (JSC) of 27.12 mA/cm2, power conversion efficiency (PCE) of 27.90% for an incident solar spectrum from the ETL side, and power conversion efficiency (PCE) of 19.86% for an incident solar spectrum from the HTL side, the calculated bifaciality factor (BF) for this structure is 71.18%.

This work studies the performance of solar cells composed of two different materials, graphene oxide (Go, hole transport material) and zirconium disulfide (ZrS2, electron transport materials) using the SCPAS -1D simulation. It has been found that Go/ZrS2 solar cells show better performance with high short circuit current, Jsc, of 38 mA/cm2 and the power conversion efficiency, η, of 17% compared with other solar cells based on graphene oxide and perovskite materials. Additionally, the short circuit current density decreases from 38 mA/cm2 to 22 mA/cm2 when the energy gap of ZrS2 increases from 1.2 eV to 17 eV. The increasing the operating temperature and the work function of back contact also led to decrease the open circuit voltage and power conversion efficiency of the cells, while the short circuit current density was slightly enhanced. That is attributed to changes in the electrical properties of Go and ZrS2 layers, including their charge carrier mobility and characteristics of the interfacial layers.

After hydrogen production, it can storage and compression for transportation is critical process. In this regard, the electrochemical hydrogen compressor, which allows simultaneous purification and compression of hydrogen, has attracted great attention in recent years. In this study, the compression performance of a single-cell electrochemical hydrogen compressor at different temperature values was investigated. Accordingly, experiments were carried out under low (50–80 °C) and high (120–180 °C) temperature conditions. The optimal polarization curve for electrochemical hydrogen compressors was reached 70 °C at low temperatures and 160 °C at high temperatures. Furthermore, increasing the cell voltage decreases compression time and improves performance. A high compression ratio was achieved at 0.8 V cell voltage. At this voltage, different times are needed at low and high temperatures to compress the hydrogen in the cathode up to 5 bar. Finally, based on the single-cell system's testing results, the stack cell can attain superior compression values. • Variation of cell temperature affects EHC performance. • The ideal compression value was reached at 70 °C and 160 °C temperatures. • The effects on EHC of some major parameters are revealed. • The cell reached the maximum cathode pressure at 0.8 V. • Data provides the basis for the development of stack EHC systems. [ABSTRACT FROM AUTHOR]

Ion conducting membranes play a crucial role in redox flow batteries, separating anolyte and catholyte while allowing proton transport to complete the circuit. However, most membranes are trapped in a trade‐off relation and show either low conductivity or high vanadium crossover. This study investigates the use of dense sulfonated para‐polybenzimidazole membranes for vanadium redox flow batteries (VRFBs), and analyzes the effects of membrane preparation process, membrane thickness and operating temperature on the VRFB performance. The results demonstrate superior performance of VRFBs utilizing fluorine‐free sulfonated para‐polybenzimidazole membranes compared to other types. Under optimal conditions, the VRFB exhibits high coulombic efficiency (>99%) and high energy efficiency (EE, 92.2% at a current density of 80 mA cm−2), and durability. The achieved EE represents one of the highest reported in the literature for VRFBs. In addition, it is shown that operation at 35 °C has benefits at high current densities (EE at 300 mA cm−2 is over 80% at 35 °C but 72% at 25 °C), while the operation at 80 mA cm−2 only shows a small temperature effect (91.8 and 92.2%, respectively). [ABSTRACT FROM AUTHOR]

Co_3 O_4 metal oxide semiconductor is in principle suitable material for utilization as a resistive gas sensor. In this research, nanostructure cobalt oxide thin films were prepared by chemical spraying pyrolysis technique, by dissolving cobalt chloride with distilled water. The films were doped with Cerium Ce in different concentrations, and the structural and morphology properties of the samples were studied. A gas sensor was prepared from doped and undoped cobalt oxide material. The response properties were studied and the operating temperature and response time of the manufactured sensor were found, the effect of doping on the sensor properties was studied. [ABSTRACT FROM AUTHOR]

The most rapidly expanding type of solar cells are the Perovskite Solar Cells (PSCs), because of its high device performance, ease of synthesis, high open-circuit voltage, and affordability. Despite these advantages, the development of perovskite-based solar cells continues to be impeded by the issues with perovskite stability and the utilization of the hazardous heavy element lead (Pb). The study emphasizes on the bifacial structure that maintains the conventional absorber layer and electron transport layer (ETL) in the optimized PSC structure. This study employs SCAPS software for device simulation to comprehensively analyze how various parameters affect the performance of solar cells. Additionally, doping concentration variation in both ETL and HTL are explored. The simulation reveals that changing device structure from monofacial to bifacial significantly influences PSC performance, demonstrating that optimizing individual layers effectively enhances overall solar cell performance. The optimized structure achieves impressive PSC performance metrics through parametric analysis, such as voltage (VOC) of 1.18 V, fill factor (FF) of 82.24%, current density (JSC) of 27.12 mA/cm2, power conversion efficiency (PCE) of 27.90% for an incident solar spectrum from the ETL side, and power conversion efficiency (PCE) of 19.86% for an incident solar spectrum from the HTL side, the calculated bifaciality factor (BF) for this structure is 71.18%. [ABSTRACT FROM AUTHOR]

In order to study the effects of temperature and humidity on the performance of proton exchange membrane fuel cell (PEMFC), a temperature and relative humidity-current (TRH-C) model was proposed. The model took the water flow and membrane water content of anode and cathode flow channels into consideration, and revealed the law of current density distribution and membrane water content distribution under the condition of current step change. According to the real flow channel configuration of the experimental single cell, a simplified PEMFC geometric model was established and the calculation grid was divided, and the TRH-C model was coupled to the multi-physical field calculation software COMSOL. A PEMFC test platform was established to test PEMFC under different temperature and humidity conditions. The operating temperatures of PEMFC were 65 °C and 70 °C, and the inlet humidities were 50% and 75%. The polarization curve, the membrane current density, and the membrane water content under different working conditions were analyzed and discussed. The results show that the TRH-C model can accurately predict the output performance of PEMFC. When the operating temperature is 70 °C, the inlet humidity is 50%, and the current density is 0. 018 A/cm², the relative errors of the TRH-C model of voltage and power density both reach the maximum value, which are 7.306% and 8.837%, respectively. The performance of PEMFC can be improved by increasing operating temperature and inlet air humidity. As the operating temperature increases, the distribution uniformity of membrane current density fluctuates and the mem-brane water content decreases. With the increase of inlet air humidity, the film current density distribution becomes more uniform and the film water content increases. This work provides a new theoretical method for optimizing inlet air strategy control and improving the output performance. [ABSTRACT FROM AUTHOR]

This work studies the performance of solar cells composed of two different materials, graphene oxide (Go, hole transport material) and zirconium disulfide (ZrS2, electron transport materials) using the SCAPS -1D simulation. It has been found that Go/ZrS2 solar cells show better performance with high short circuit current, Jsc, of 38 mA/cm2 and the power conversion efficiency, η, of 17% compared with other solar cells based on graphene oxide and perovskite materials. Additionally, the short circuit current density decreases from 38 mA/cm2 to 22 mA/cm2 when the energy gap of ZrS2 increases from 1.2 eV to 17 eV. The increasing the operating temperature and the work function of back contact also led to decrease the open circuit voltage and power conversion efficiency of the cells, while the short circuit current density was slightly enhanced. That is attributed to changes in the electrical properties of Go and ZrS2 layers, including their charge carrier mobility and characteristics of the interfacial layers. [ABSTRACT FROM AUTHOR]

Metal-oxide-semiconductors (MOS) gas sensors are widely used for detecting and measuring the concentration of various gases in different applications. Changing the electrical resistance when the MOS surface reacts with a specific gas is the basis of the operation of the gas sensor of MOS. They offer versatility in detecting various gases and fabricating them suitable for supervising energy efficiency, monitoring health and safety, and controlling hazardous emissions. However, traditional MOS sensors suffer from poor selectivity and usually require high operating temperatures. To overcome these limitations, researchers have explored strategies such as doping, bimetallic/co-doping, and composite structures with conductive polymers and 2D materials such as polyaniline (PANI), polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), reduced graphene oxide (rGO), graphitic carbon nitride (g-C3N4), and graphene. Among the 2D materials, g-C3N4 stands out due to its distinct characteristics, including chemical stability, porosity structure, abundance, lack of toxicity, and numerous surface defects. The exfoliated structure and surface defects of g-C3N4 provide active sites for adsorbing atmospheric oxygen and facilitating reactions with specific gas molecules. This review introduces MOS gas sensors, covering their fabrication methods and electrical measurements. It then attentions on the properties of g-C3N4, synthesis methods, and its potential for composition with the MOS. The review highlights the enhanced gas sensing performance achieved by MOS/g-C3N4 nanocomposites to detect different gases.

The performance of proton exchange membrane fuel cells (PEMFCs) is significantly influenced by their temperature and cathode humidity, as they affect power density and internal water distribution. The interdependent nature of these two parameters necessitates their simultaneous consideration in practical engineering to achieve high efficiency and reliable PEMFC operation. Therefore, this study proposes a synergistic analysis of the dual-parameter effect of working temperature and cathode humidity on PEMFC performance, using a three-dimensional steady-state model for counter-flow single-channel PEMFCs. The model's correctness is verified through comparison with experimental results, and the resulting power density and internal water distribution characteristics of PEMFCs are studied based on voltage changes. The findings indicate that the sensitivity of the proton exchange membrane (PEM) to temperature and cathode humidity varies at different voltage stages. Coupling analysis of these two factors enhances proton exchange membrane conductivity and expands the range of power density adjustment. Consequently, this study provides crucial insights into the interplay between temperature and cathode humidity in PEMFCs, facilitating the design and optimization of PEMFC systems for practical engineering applications.

Aviation soot constitutes a significant threat to human well-being, underscoring the critical importance of accurate measurements. The condensation particle counter (CPC) is the primary instrument for quantifying aviation soot, with detection efficiency being a crucial parameter. The properties of small particles and the symmetry of their growth pathways are closely related to the detection efficiency of the CPC. In laboratory environments, sodium chloride is conventionally utilized to calibrate the CPC's detection efficiency. However, aviation soot exhibits distinctive morphological characteristics compared to the calibration particles, leading to detection efficiencies obtained from calibration particles that may not be applicable to aviation soot. To address this issue, a quantitative study was performed to explore the detection efficiency deviations between aviation soot and calibration particles. The experiment initially utilized a differential mobility analyzer to size select the two types of polydisperse particles into monodisperse particles. Subsequently, measurements of the separated particles were performed using the TSI Corporation's aerosol electrometer and a rigorously validated CPC (BH-CPC). These allowed for determining the detection efficiency deviation in the BH-CPC for the two types of particles at different particle sizes. Furthermore, the influence of the operating temperature of the BH-CPC on this detection efficiency deviation was investigated. The experimental results indicate a significant detection efficiency deviation between aviation soot and sodium chloride. In the range of 10–40 nm, the absolute detection efficiency deviation can reach a maximum of 0.15, and the relative deviation can reach a maximum of 0.75. And this detection efficiency deviation can be reduced by establishing a relevant relationship between the detection efficiency of the operating temperature and the calibration temperature. Compared to the saturated segment calibration temperature of 50 °C, the aviation soot detection efficiency is closer to the sodium chloride detection efficiency at the calibration temperature of 50 °C when the saturated segment operates at a temperature of 45 °C. These studies provide crucial theoretical guidance for enhancing the precision of aviation soot emission detection and establish a foundation for future research in monitoring and controlling soot emissions within the aviation sector. [ABSTRACT FROM AUTHOR]

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Polymer-dispersed liquid crystal (PDLC) films are electrically controlled dimming films. By applying an electric field to the PDLC film, it becomes transparent, whereas in the absence of an electric field, the PDLC film is opaque. In recent years, with the development of new-energy vehicles, the utilisation of glass curtains instead of the conventional skylight or sunshade has become a trend, because the combination of PDLC films and glass can realise random switching between shading and transparency; thus, it has great application prospects in the automotive industry. However, the low operating temperature of PDLC films limits their application. In this study, a characterisation method for PDLC film performance at high temperatures is discussed, and the effect of SiO2 microspheres on the high-temperature properties of PDLC films is investigated. When the proportion of doped SiO2 was 1.5%, the maximum operating temperature reached 95°C, and the light transmittance and hazeon (power on) did not change compared with the PDLC film without doped SiO2. The utilisation of the power-off haze at high temperature as a performance index of PDLC films has universal significance for the evaluation of the high-temperature resistance of these materials. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model for stacks of direct methanol fuel cells (DMFCs) using an optimised method. In order to reduce the sum of squared errors (SSE) in calculating the polarisation profile, the suggested technique makes use of simulated experimental data. Given that DMFC is one of the viable fuel cell choices, developing an appropriate model is essential for cost reduction. However, resolving this issue has proven difficult due to its complex and highly nonlinear character, particularly when adjusting the DMFC model to various operating temperatures. By combining the algorithm and the objective function, the current work introduces a novel method called LSHADE (ELSHADE) for determining the parameters of the DMFC model. This technique seeks to accurately identify DMFCs' characteristics. The ELSHADE method consists of two stages, the first of which is controlled by a reliable mutation process and the latter by a chaotic approach. The study also recommends an improved Newton–Raphson (INR) approach to deal with the chaotic nature of the I-V curve equation. The findings show that, when used on actual experimental data, the ELSHADE-INR technique outperforms existing algorithms in a variety of statistical metrics for accurately identifying global solutions. [ABSTRACT FROM AUTHOR]

The sensitivity of the operating parameters of proton exchange membrane fuel cells is essential to improve the performance and water management capabilities of the stack. The current research on proton exchange membrane fuel cell sensitivity is mainly focused on simulations and experimental methods for small activation area single cells, but less research literature for commercial stack with larger effective area. In this work, a commercial stack with an effective area of 300 cm2 membrane electrode is as the research object. The polarization curves under different operating conditions are obtained by experiment, and the voltage data are processed with first-order derivatives to systematically analyze the effects of gas relative humidity, stoichiometric ratio, inlet gas pressure and operating temperature on the performance of the stack. It was found that a certain degree of cathode inlet relative humidity, cathode stoichiometry ratio, in inlet pressure and in temperature are beneficial to the stack performance and are closely related to stack water management. However, with the cathode gas relative humidity reaching 45%, the cathode stoichiometry ratio increasing to 1.9 and the operating temperature increasing to 76°C, the stack performance does not improve significantly. And the excessive increase in operating parameters is likely to have a negative impact on the stack performance. The stack performance is less sensitive to the anode stoichiometry ratio and anode gas relative humidity, and when the anode stoichiometry ratio is lower than 1.3, it will have a great negative impact on the stack performance. These are important for the development of controlling the operating parameters for commercial fuel cell. [ABSTRACT FROM AUTHOR]

Direct methanol fuel cell (DMFC) is a device which converts chemical potential energy into electrical energy through the electrochemical reaction that involves oxidation of methanol. This study investigates the underlying voltage loss mechanism and determines how a change in process conditions will affects the resulting voltage loss, through the development of a one-dimensional mathematical DMFC model in software (MATLAB). The one-dimensional mathematical model has adopted a modelling approach that is simple and relatively easy to be constructed, thus providing a method for simple yet accurate estimation of the DMFC voltage loss curve. The study is conducting in three stages, which include the construction of preliminary model, model parameter fitting and model simulation. Based on the developed DMFC model, the polarization curve of a DMFC are dividing into three regions, including activation polarization-controlled region, ohmic drop controlled region and concentration polarization-controlled region. In each of these regions, one of the voltage loss mechanisms is the dominant mechanism that causes the greatest voltage loss. Voltage loss from all three mechanisms are finding to be reduced at higher temperature. The simulated DMFC can operate at a maximum power density of 0.15 W/cm2, with a voltage efficiency of 33.9%. This model operates at temperature of 343K and uses 2M methanol concentration.

Solid-state dye-sensitized solar cells (SSDSC) have been fabricated using two different metal oxide materials, graphene oxide and titanium oxide, are used as hole and electron transport materials, respectively. The N719 dye ruthenium between the hole and electron transport materials to act as an absorber layer in your Go/N719dye/TiO2 solar cells. Through the SCAPS-1D simulation, it was found that the Go/N719dye/TiO2 solar cells have significantly improved the performance of the solar cells compared to the Go/TiO2 solar cells. Specifically, the short circuit current (Jsc) has increased from 0.17 mA/cm2 to 1 mA/cm2, the open circuit voltage (Voc) has increased from 0.2 V to 1 V, and the power conversion efficiency (η) has increased from 0.02% to 2.5%. Additionally, Various factors that can affect the performance of Go/N719 dye/TiO2 solar cells. It was found that the optimal dye thickness for achieving high short circuit current density, high power conversion efficiency, and high open circuit voltage is between 200nm and 300nm. Furthermore, the operating temperature of the solar cells also affects their performance. Increasing the operating temperature negatively affects the open circuit voltage and power conversion efficiency of the cells, while the short circuit current density is slightly enhanced. Finally, the efficiency of a solar cell can be affected by the type of metal used for the electrode and the type of semiconductor material used in the cell. In Ni and Cu electrodes solar cells ohmic contacts allow for efficient transfer of electrons, whereas Schottky barriers can impede electron flow and reduce efficiency in Mo and Ag electrodes solar cells .

For the leakage problem of the sealing surface of the subsea flange connector, the flow factors of the isotropic rough surfaces were used to modify the parallel plate leak model, and the relationship between the film thickness ratio and the leaking rat was established. By using MATLAB and COMSOL software, the contact surface entity was generated, three root-mean-square (RMS) roughness surfaces were analyzed by finite element method at four operating temperatures, and the relationship between the average contact pressure of rough surface and the film thickness ratio was obtained. The relationship between the average contact pressure and leakage rate of three rough surfaces at four operating temperatures was established by mathematical derivation and curve fitting. The results show that the operating temperature has a great influence on the surface quality requirements of the lenticular gasket. When the operating temperature is from 20 t to 100 t, the lenticular gasket with RMS roughness of 0. 4 μm can meet the requirements of the leakage rate index, while when the high temperature oil production operation is from 100 °C to 150 °C, only the RMS roughness of 0. 2 μm can meet the leakage rate index requirements. [ABSTRACT FROM AUTHOR]

The performance of photovoltaic (PV) modules is affected by the increase in their operating temperature. Accurate and reliable prediction of the PV module operating temperature (TM) is useful for evaluating their electrical performance and productivity and predicting the maximum power point under changing weather conditions. Based on experimental measurements collected during 1 year by a station placed in a semi-arid coastal region, in Morocco, several models are investigated to predict TM of polycrystalline PV modules. Starting from existing models in the literature, models have been developed to improve the accuracy of their prediction in the studied climate. The results show that irradiance (G) and ambient temperature are the most influential parameters for estimating the TM of the studied PV module. The accuracy of the prediction can be improved by introducing the effects of Vw and RH in the proposed models. In addition, using the physical parameter extraction results of the studied modules, equations are established to approximately predict their behavior as a function of TM and G. Taking into account the proposed TM models, these equations describing the physical parameter evolution can constitute an important basis for predicting PV module performance under real operating conditions. [ABSTRACT FROM AUTHOR]

This article discusses the possibilities and limitations of CdZnTe (CZT) quasi-hemispherical detectors operating over a wide temperature range and at high-gamma radiation fluxes. The results of the negative influence of low- and high-operating temperatures, as well as high-radiation fluxes on spectrometric characteristics of CZT detectors and possible ways to eliminate performance deterioration, are presented. The impact of infrared (IR) illumination parameters, such as wavelength and irradiation intensity on the spectroscopy performance of detectors, was investigated. A correctly chosen IR illumination wavelength and intensity were shown to significantly improve the energy resolution of CZT quasi-hemispherical detectors, allowing their stable operation in high-gamma radiation fluxes and extend the operating temperature range toward low temperatures. The influences of bias voltage values and temperatures on the quasi-hemispherical CZT detectors' operating ability at high-gamma radiation fluxes were studied. [ABSTRACT FROM AUTHOR]

Sodium-ion conducting solid polymer electrolyte (Na-SPE) films based on polyvinyl alcohol (PVA) with various weight percentages of sodium iodide (NaI) were prepared using the casting technique. The films' structural, morphology and electrical conductivity were examined to understand the sensing mechanism of the as-prepared Na-SPE films. The X-ray diffraction (XRD) and atomic force microscopy (AFM) data, respectively, showed the amorphous and homogeneous granular structure of Na-SPE films due to the high dissociation of NaI in the PVA matrix for all concentrations. The changes in the FTIR vibrational modes of Na-SPEs provide evidence of interactions between cations and functional groups of the host matrix. The effect of salt content, operating temperature and gas concentration on the performance of the Na-SPE sensor towards NO2 were investigated. In contrast to the pure PVA film, which did not respond to NO2 gas at low concentrations, Na-SPE films exhibit higher sensitivity to NO2 gas with faster response and recovery times. At low NO2 gas concentration (50 ppm), a sample containing 20 wt.% of NaI exhibits the highest sensitivity at the operating temperature of 200 °C. In comparison, at a high NO2 gas concentration (550 ppm), a sample containing 40 wt.% of NaI exhibits a maximum sensitivity at 150 °C. These findings suggest that Na-SPE films would be suitable for gas sensor applications. [ABSTRACT FROM AUTHOR]

A mathematical description of the operating temperature of each of the five constituent stages of regimes for autoclave steaming and subsequent air conditioning of wood has been proposed. This description has been included in the boundary conditions of two coupled own non-stationary temperature-energy models of the autoclave steaming process of wooden prisms intended for veneer production. Using these models, calculation of the durations of the initial part and of the whole regimes for steaming of beech prisms have been carried out. The variables were an initial wood temperature of 0 and –20 °C, moisture content of 0.4, 0.6, and 0.8 kg·kg−1, and cross-section dimensions of the prisms 0.3 × 0.3 m and 0.4 × 0.4 m; steaming autoclave with a diameter of 2.4 m, length of 10.6 m, and loading level of 40, 50, and 60% at limited thermal power of 500 kW suplied to the autoclave. The simulations carried out using Visual Fortran showed a good agreement of the proposed mathematical description with many previously obtained experimental results and confirmed the possibility of its being applied in the boundary conditions of various non-stationary models of autoclave treatment processes (steaming, impregnation, desired property modification) of wood and other materials. [ABSTRACT FROM AUTHOR]

Metasurface tuning is performed using different ways for a wide range of applications. This study presents the design of a thermally‐tuned all‐dielectric reconfigurable metasurface. A microfluidic channel, filled with different concentrations of tellurium–selenium (Te‐Se) alloy, is added on the top of the elliptical dielectric resonator (EDR) unit cell of the considered metasurface. The electrical properties of used semiconductor alloy are varied in the range of 400 to 700°C (steps size of 100°C). The impact of thermal tuning on the reflection and transmission characteristics of the designed metasurface is analyzed in the frequency range of 20–30 GHz using COMSOL Multiphysics. Obtained results demonstrated that the realized metasurface exhibits reconfigurable behavior in terms of variations in the reflection and transmission characteristics with a change in either temperature or concentrations of selenium and tellurium. The wider bands with high reflection and low transmission frequency bands are obtained with lower concentrations of selenium and tellurium for all operating temperatures. [ABSTRACT FROM AUTHOR]

This paper presents the theoretical and experimental investigation on performance of a photovoltaic (PV) panel cooled by porous media under indoor condition. Porous media offer a large exterior surface area and a high fluid permeability, making them ideal for PV cells cooling. The photovoltaic panel was cooled using 5 cm thick cooling channel filled with porous media (gravel). Several sizes of porosity (0.35, 0.4, 0.48, and 0.5) at different volume flow rates (1, 1.5, 2, 3, and 4 L/min) were tested to obtain the best cooling process. The theoretical analysis was performed at the optimum case found experimentally, which has a porosity of 0.35 and a volume flow rate of 2 L/min, to test various experimental results of the PV hot surface temperature, related power output, efficiency and I-V characteristic curve. The enhancement obtained in PV power output and efficiency is compared against the case without cooling and the case using water alone without porous media. Results showed that cooling using small size porous media and moderate flow rate is more efficient which reduces the average PV hot surface temperature of about 55.87% and increases the efficiency by 2.13% than uncooled PV. The optimum case reduced the PV hot surface temperature to 38.7°C, and increased the power output to 19 W, efficiency to 6.26%, and the open voltage to 22.77 V. The results showed that the presence of small porous media of 0.35 in the PV cooling process displayed the maximum effectiveness compared to the other two scenarios, because the heat loss from PV surface through porous media layer have developed a homogenous heat diffusion removed much quicker at high flow rate (2 L/min). A good agreement was obtained between experimental and theoretical results for different cases with a standard deviation from 3.2% to 5.6%.

The Chemical Looping Combustion (CLC) technique shows great potential as an innovative technology to enhance thermal efficiency of system. It has a capability to achieve complete carbon capture (up to 100 %) and prevent the formation of nitrogen oxides (NOx). The current study focuses on the computational analysis of bubble behavior within fuel reactor of CH4-fueled Chemical Looping Combustion (CLC) setup. During numerical examination, a user-defined function (UDF) was utilized to integrate a reaction kinetics into active environment of fuel reactor. In the current research, CuO and NiO are employed as mixed oxygen carrier substances, while CH4 is utilized as fuel within the combustion procedures. The preparation, growing, rising, and bursting of bubbles' hydrodynamics has been observed; additionally, it has been evaluated in addition to examining the solidus-gaseous molar fraction within a fuel reactor. The current simulation opted for a gaseous fuel composed of natural gas (CH4), a hydrocarbon, alongside mixed metal oxides as CuO and NiO in varying ratios. A mixed metal oxide has been chosen in the proportion of CuO as 0.3 and NiO as 0.7, CuO as 0.5 and NiO as 0.5, and CuO as 0.7 and NiO as 0.3 by weightage. The fuel conversion rate has been observed 20 %, 25 %, and 30 % respectively for the different metal oxide mixture proportions. It has been clearly noticed that in the mixture of NiO and CuO; if the CuO amount is more, then the fuel conversion rate is high due to highly reactivity of CuO at high temperatures.

Abstract Metasurface tuning is performed using different ways for a wide range of applications. This study presents the design of a thermally‐tuned all‐dielectric reconfigurable metasurface. A microfluidic channel, filled with different concentrations of tellurium–selenium (Te‐Se) alloy, is added on the top of the elliptical dielectric resonator (EDR) unit cell of the considered metasurface. The electrical properties of used semiconductor alloy are varied in the range of 400 to 700°C (steps size of 100°C). The impact of thermal tuning on the reflection and transmission characteristics of the designed metasurface is analyzed in the frequency range of 20–30 GHz using COMSOL Multiphysics. Obtained results demonstrated that the realized metasurface exhibits reconfigurable behavior in terms of variations in the reflection and transmission characteristics with a change in either temperature or concentrations of selenium and tellurium. The wider bands with high reflection and low transmission frequency bands are obtained with lower concentrations of selenium and tellurium for all operating temperatures.

The performance of the solid oxide fuel cell (SOFC) is greatly influenced by its operating temperature. Therefore, making a profound study of the thermal characteristics inside the SOFC stack and maintaining the operating temperature within a reasonable range are the difficulties. This paper proposes a novel modeling and control strategy. Firstly, for studying the thermal characteristics of SOFC under variable load current and designing a more effective control schedule, the problem of SOFC temperature dynamic modeling is resolved by the beetle antennae search (BAS) optimizing–based back propagation (BP) neural network model (BAS-BP) innovatively. The simulation indicated that the mean absolute error (MAE), mean absolute percentage error (MAPE), and mean square error (MSE) of the designed BAS-BP algorithm are 19.14%, 24.51%, and 27.67% lower than those of the traditional BP model. The designed modeling method is armed with higher accuracy and faster convergence speed. Then, a sliding mode controller (SMC) based on the disturbance observer is represented in this paper, wherein the disturbance observer is first presented to predict disturbance functions, while the SMC realizes the tracking control of the SOFC node temperature by compensating for the observation error instead of ignoring it. It can be seen from the simulation that the proposed control strategy compared to the conventional proportional-integral-derivative (PID) controller achieves a 62.57%, 61.11%, and 6.27% reduction in MAE, MAPE, and MSE. The simulated results demonstrate that the presented strategy has better robustness to disturbances in addition to its validity in compensating for observation error, for the SOFC node temperature control. [ABSTRACT FROM AUTHOR]

This paper reports a study of a gas sensor based on nanostructured zinc oxide in order to establish the conditions for its production and operating characteristics under the influence of the target gas ethanol. The studied samples were produced by magnetron sputtering on direct current. The method of forming the device structure was chosen among others due to the fact that it has a high rate of deposition at low values of the working gas pressure, there is no overheating of the substrate, a low degree of contamination of the obtained films, the possibility of obtaining samples of uniform thickness on a large area of the substrate. A VUP-5M vacuum unit with an original material-saving magnetron was used to obtain the films. Studies of the effect of temperature on the resistance of a gas sensor based on ZnO have been carried out. It was established that the change in the resistance of the tested sample depends on the temperature of the substrate. The resistance of the gas sensor in atmospheric air decreases with increasing substrate temperature from room temperature (25 °C) to 200 °C. A further increase in temperature from 200 °C leads to an increase in the resistance of the structure until it stabilizes in the temperature range of 300–400 °C. It was established that the operating temperature range of the gas sensor based on ZnO is within 300–400 °C. The characteristics of the gas sensor based on ZnO were studied and the working temperature of the sensor was determined for the rapid identification of ethanol in atmospheric air at a target gas concentration of 500 ppm. It was established that for rapid operation of the instrument structure, the temperature of the substrate should be 400 °C, a decrease or increase in temperature leads to a decrease in the sensitivity of the sensor to the target gas. It was established that the gas sensor demonstrates stability and a consistent sensitivity response upon repeated exposure to the target gas. [ABSTRACT FROM AUTHOR]

A cell model is developed and validated to analyze the performance of polymer electrolyte membrane water electrolysis (PEMWE) stacks and systems. It is used to characterize the oxygen evolution reaction (OER) activity on a TiO2-supported IrO2 catalyst and an unsupported IrO2 powder catalyst. Electrochemical, stack, and system thermoneutral potentials are defined and determined for isothermal and non-isothermal stack operation. Conditions are determined under which the system thermoneutral potential or flammability of H2 in the O2 anode stream limits the stack turndown and operating temperature. Performance is analyzed of a complete PEMWE system with an electrolyzer stack containing an IrO2/TiO2 anode catalyst (2 mg/cm2 Ir loading) and N117-like membrane mitigated for H2 crossover, anode balance-of-plant (BOP) components, cathode BOP system with temperature swing adsorption for H2 purification, and electrical BOP system with transformer and rectifier. At the rated power condition, defined as 2 A/cm2 at 1.9 V, 80 °C, and 30 bar H2 pressure, the stack/system efficiency is 65.3%/60.3% at beginning of life (BOL), decreasing to 59.3%/53.9% at end of life (EOL). The peak stack/system efficiency is 76.3%/70.2% at BOL, decreasing to 71.2%/65.6% at EOL. Improvements in catalyst activity and membrane are identified for a 50% increase in current to 3 A/cm2 at 1.8 V. [ABSTRACT FROM AUTHOR]

The paper discusses diverse energy storage technologies, highlighting the limitations of lead-acid batteries and the emergence of cleaner alternatives such as lithium-ion batteries. It covers battery inspections, factors affecting battery life, and repurposing retired batteries. Additionally, it addresses challenges in wind power generation and the successful application of LL-type VRLA batteries in stabilizing power fluctuations. [ABSTRACT FROM AUTHOR]

We describe ultra‐high sensitive force sensor on flat display that can detect and differentiate between feather touch and press touch or tapping. The proposed unique sensor pattern design and pressure‐sensitive material enables ultra‐high force sensitivity, multi force detection (10 points). Our force touch technology with button‐shaped bumps cover enables blind input operations and usability as good as mechanical buttons. Therefore, our technology provides reduced input errors and yield more intuitive and safedrive. In addition, the proposed novel algorithm enables an operating temperature range for automotive applications. [ABSTRACT FROM AUTHOR]

Intermediate temperature solid oxide fuel cell (IT-SOFC) provides economic and technical advantages over the conventional SOFC because of the wider material use, lower fabrication cost and longer lifetime of the cell components. In this work, we fabricated electrolyte-supported IT-SOFC using low-cost materials such as calcia-stabilized zirconia (CSZ) electrolyte fabricated by dry-pressing, NiO-CSZ anode and Ca3Co1.9Zn0.1O6 (CCZO) cathode produced through brush coating technique. According to the XRD result, the monoclinic phase dominated over the cubic phase, and the relative density of the electrolyte was low but the hardness of the CSZ electrolyte was close to the hardness of commercial 8YSZ electrolyte. The performance of the single cell was performed with hydrogen ambient air. An open-circuit voltage (OCV) of 0.43, 0.46, and 0.45 V and a maximum power density of 0.14, 0.50, and 1.00 mW/cm2 were achieved at the operating temperature of 600, 700, and 800 °C, respectively. The ohmic resistance of the cell at 700 and 800 °C achieved 81.5 and 33.00 Ω, respectively due to the contribution of thick electrolyte and Cr poisoning in electrodes and electrolyte

The current study developed an analytical model to predict the PV module’s operating temperature based on an experimental database, which considers cell temperature, local meteorological data (irradiance, ambient temperature, wind velocity, and humidity), voltage, and current generated by the photovoltaic system associated with the purely resistive load. Based on the analysis of the 172-day database, it was possible to compare the most used correlations in the literature with the analytical model developed in the current work. For all conditions, the model showed a better response to climate variation – with 100% of the data within an error band of ± 20% and an absolute mean percentage error of 3.1% – predicting well the PV module’s operating temperature for both sky conditions (clear or cloudy) and demonstrated that the thermal capacity of the PV module to climatic variations should not be neglected. Moreover, the new model considered the PV module’s thermal response capacity to include the variations in the incident solar irradiance caused by the presence of clouds (shading effect). By considering a global heat capacity as a mean value of the heat capacities of the layers of the PV module, the term transient – generally neglected in several works – is considered in the energy equation in the current work, which gives a better response to the variations in the incident radiation.

Reduction in friction ensures fuel economy, control on emissions and durability of components in internal combustion engines. A modern gasoline internal combustion engine was instrumented to determine the friction values at the cam–roller interface considering the effects of surface treatment and engine operating state. A series of tests under different operating speeds and lubricant inlet temperatures were undertaken using both an original surface roller and a Wonder Process Craft (WPC) surface-treated engine roller. The results clearly revealed a substantial reduction in friction magnitude for the WPC surface-treated engine roller in comparison to the original roller while operating under similar conditions, indicating their strong potential for employment in engines. An increase in friction with the rise in temperature was also observed for both types of rollers, whereas increased lubricant entraining velocity due to higher operating speed had the opposite impact. A considerable reduction in frictional drive torque ranging from 8% to 28% was observed by employing the WPC-treated roller in comparison to original/untreated roller at various operating conditions, which signifies the strong potential for employment of WPC surface treatment in the roller/follower valve train engines. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of operating temperature on the reverse solute diffusion, the forward osmosis-only model incorporating the surface charge on solute partitioning is developed to obtain the reverse solute flux as a function of operating temperature and draw solution concentration using MATLAB. By comparing the calculated reverse solute flux for bulk draw solution concentrations at different operating temperatures, the range of the draw solution concentration at the support layer-active layer interface applicable to the constant surface charge density is found. The concentration beyond which the surface charge density is not constant, which is caused by the variety of the Debye length with the draw solution concentration, decreases with increasing operating temperature. The dilutive internal concentration polarization at 45°C is greater than that at 25°C due to the greater structural parameter and ratio of the structural parameter to diffusion coefficient at 45°C. The lower reverse solute flux at 45°C than that at 25°C is due to the fact that the ratio of the effective concentration between 25°C and 45°C outweighs that of the effective solute permeability coefficient. [ABSTRACT FROM AUTHOR]

The influence of parameters that cause the degradation of polymer electrolyte membrane fuel cells on the performance is analyzed. The degradation phenomenon in various temperature and relative humidity is analyzed through polarization and cyclic voltammetry curves, the cell impedance and electrochemical surface area. After long-term operation, a performance degradation of up to 25.3 % and 75.71 % is observed when the operating temperature is 90 °C, and relative humidity is 10 %. When the operating temperature exceeds the favorable temperature (60–80 °C), the Nafion structure is destroyed, which promotes degradation owing to carbon corrosion and catalyst aggregation. The ion conductivity of membrane rapidly decreases, when the relative humidity is 10 %, and degradation is accelerated. The prediction model can identify conditions in which the most severe degradation occurs in different operational situations. This finding can facilitate the development of an effective degradation protocol for performance prediction based on the consideration of individual influencing factors. [ABSTRACT FROM AUTHOR]

Molten carbonate fuel cells (MCFCs) use molten carbonate as an electrolyte. MCFCs operate at high temperatures and have the advantage of using methane as a fuel because they can use nickel-based catalysts. We analyzed the performance of an internal manifold-type MCFC, according to operating conditions, using computational fluid dynamics. Different conditions were used for the external and internal reforming-type MCFCs. Flow directions, gas utilization, and operating temperatures were used as the conditions for the external reforming-type MCFCs. The S/C ratio and reforming area were used as the conditions for internal reforming-type MCFCs. A simulation model was developed, considering gas transfer, reforming reaction, and heat transfer. The simulation results of external reforming-type MCFCs showed similar pressure drops in all flow directions. As the gas utilization decreased, the temperature decreased, but the performance increased. The performance improved with increasing operating temperatures. The simulation results for the internal reforming-type MCFCs showed that more hydrogen was produced as the S/C ratio decreased, and the performance increased accordingly. More hydrogen was produced as the reforming area increased. However, similar performance was obtained when the reforming area contained the same active area. The external and internal reforming-type MCFCs were compared under the same conditions. The efficiency of the external reforming-type MCFCs is higher than that of the internal reforming-type MCFCs. [ABSTRACT FROM AUTHOR]

This paper presents the theoretical and experimental investigation on performance of a photovoltaic (PV) panel cooled by porous media under indoor condition. Porous media offer a large exterior surface area and a high fluid permeability, making them ideal for PV cells cooling. The photovoltaic panel was cooled using 5 cm thick cooling channel filled with porous media (gravel). Several sizes of porosity (0.35, 0.4, 0.48, and 0.5) at different volume flow rates (1, 1.5, 2, 3, and 4 L/min) were tested to obtain the best cooling process. The theoretical analysis was performed at the optimum case found experimentally, which has a porosity of 0.35 and a volume flow rate of 2 L/min, to test various experimental results of the PV hot surface temperature, related power output, efficiency and I-V characteristic curve. The enhancement obtained in PV power output and efficiency is compared against the case without cooling and the case using water alone without porous media. Results showed that cooling using small size porous media and moderate flow rate is more efficient which reduces the average PV hot surface temperature of about 55.87% and increases the efficiency by 2.13% than uncooled PV. The optimum case reduced the PV hot surface temperature to 38.7°C, and increased the power output to 19 W, efficiency to 6.26%, and the open voltage to 22.77 V. The results showed that the presence of small porous media of 0.35 in the PV cooling process displayed the maximum effectiveness compared to the other two scenarios, because the heat loss from PV surface through porous media layer have developed a homogenous heat diffusion removed much quicker at high flow rate (2 L/min). A good agreement was obtained between experimental and theoretical results for different cases with a standard deviation from 3.2% to 5.6%. [ABSTRACT FROM AUTHOR]

Solid/solid interface is the major challenge for high‐performance solid‐state batteries. Solid electrolytes (SEs) play a crucial role in the fabrication of effective interfaces in solid‐state batteries. Herein, the electrolyte distribution with varied particle sizes is tuned to construct solid‐state batteries with excellent performance at different operating temperatures. Solid‐state batteries with the configuration S/L (small‐sized SE in composite cathode and large‐sized SE in electrolyte layer) show the best performance at room temperature (168 mA h g−1 at 0.2 C, retention of 99%, 100 cycles) and −20 °C (89 mA h g−1 at 0.05 C), while the configuration S/S displays better performance at elevated temperature. The superior performance of S/L battery is associated with faster lithium‐ion dynamics due to the better solid/solid interface between active materials and electrolytes. Moreover, the inferior performance at 60 °C is caused by the formation of voids and cracks in the electrolyte layer during cycling. In contrast, the S/S battery delivers superior performance at elevated operating temperature because of the integrated structure. This work confirms that tailoring electrolyte size has significant effect on fabricating all‐climate solid‐state batteries. [ABSTRACT FROM AUTHOR]

This review considers advances in the field of epoxy adhesives that can work at elevated and negative temperatures. Methods for modifying epoxy adhesives and examples of adhesive materials for operation in a wide temperature range have been considered. [ABSTRACT FROM AUTHOR]