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The authors report experimental investigations on Hall sensors based on AlGaN/GaN heterojunctions grown on silicon 111 (Si 111) substrates. Realisation of two-dimensional electron gas-based Hall sensors on Si substrates can have the advantages of low cost and integrability with complementary metal-oxide semiconductor circuits. Design and fabrication of such Hall sensors and their characterisation over a wide temperature range of 75 to 500 K are reported. The authors experimentally investigate the temperature dependence of the transresistances, sheet resistance and current-related sensitivity (or gain) of such Hall sensors. The current-related sensitivity is shown to be reasonably constant over the complete temperature range and certain inevitable variations in current-related sensitivity can easily be compensated. The temperature dependence of the transresistance can be used for such compensation. The variation of the geometrical correction factor of the Hall sensor with the applied magnetic field strength and the operating temperature is also studied. The authors also demonstrate the possibility of realising Hall sensors with a high geometrical correction factor (�0.97), which is practically insensitive to variations in temperature (�2 from 75 to 500 K) and applied magnetic field, for applications such as in electromechanical devices. © 2021 The Authors. IET Circuits, Devices & Systems published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.

Internal dry reforming (IDR) of methane for biogas-fed solid oxide fuel cell (SOFC) applications has been experimentally investigated on planar Ni-GDC (cermet anode) electrolyte-supported cells. This study focuses on the effect of CO2 concentration, current density, operating temperature, and residence time on internal methane dry reforming. A single cell is fed with different CH4/CO2 mixture ratios between 0.6 and 1.5. Extra CO2 recovered from carbon capture plants can be utilized here as a reforming agent. The I-V characterization curves are recorded at different operating conditions in order to determine the best electrochemical performance while the power production is maximized, and carbon deposition is suppressed. The outlet gas from the anode is analyzed by a micro gas chromatograph to investigate methane conversion inside the anode fuel channel and to understand its influence on the cell performance. Relatively long-term experiments have been performed for all gas mixtures at 850°C under a current density of 2000 A m−2. The results indicate that when the cell is fed with biogas with an equimolar amount of CH4 and CO2, carbon deposition is prevented, and maximum power density is obtained.

The operating temperature of PV modules affects the rate of degradation. We show the extent to which module operating temperature can be reduced by increasing the efficiency of the PV module via a tandem architecture or singlet Fission, the latter being of interest as a potentially endothermic process. PV modules that employ tetracene as a singlet fission material are found to be resilient against degradation since the degradation product is transparent to solar radiation.

Room-temperature (RT) sodium-sulfur (Na/S) battery has been considered as a promising energy storage system due to suitable operating temperature, high theoretical energy density, and low cost. However, it has a poor cycle life and low reversible capacity. In this work, we report a long-life RT-Na/S battery with the help of amorphous porous silica as a sulfur host. The sulfur is loaded into amorphous silica by a facile dipping method, and the optimal sulfur loading can be as high as 73.48 wt.%. The molecular dynamics simulation and first-principles calculations suggest that the complex pores, acting as micro-containers and the formation of Na-O chemical bonds between amorphous silica and sodium polysulfide, give the electrodes a strong ability to inhibit sodium polysulfide shuttle. This would give rise to effectively avoiding the loss of active sulfur, corresponding to a superior capacity (i.e., average discharge capacities of 1106, 1074, 1060, 1036, and 1000 mAh·g -1 at 1, 2, 3, 5, and 10 A·g -1 , respectively.) and an excellent cyclability even at 10 A·g -1 (nearly 100% coulomb efficiency and high reversible capacity of 955.8 mAh·g -1 after 1460 cycles). The present results introduce new insights into the inhibition of "shuttle effect" of sodium polysulfide and develop a promising sulfur electrode for advanced RT sodium-sulfur batteries.

Based on the preliminary investigation of the intermediate temperature sodium-sulfur (IT-NaS) battery (150 °C), herein we advance this energy storage system, by re-tuning the catholyte formulation; namely i) concentration, ii) layer thickness and iii) cut-off limits during galvanostatic charge-discharge cycling, lowering the operating temperature and improving cell design. The systematic implementation of these strategies boosted the cell performance markedly, delivering 112 mAh/g-sulfur, 90% of its theoretical specific capacity (125 mAh/g-sulfur), and 50 deep reversible charge-discharge cycles with coulombic and round-trip energy efficiencies of 97 ± 3% and 73 ± 4%, respectively. Along with the stability and improvement of cycle life, this study demonstrates, for the first time, the practicality of the tubular IT-NaS technology at a temperature as low as 125 °C.

Na1/2Bi1/2TiO3-based materials have been earmarked for one of the first large-volume applications of lead-free piezoceramics in high-power ultrasonics. Zn2+-doping is demonstrated as a viable route to enhance the thermal depolarization temperature and electromechanically harden (1-y)Na1/2Bi1/2TiO3-yBaTiO3(NBT100yBT) with a maximum achievable operating temperature of 150 °C and mechanical quality factor of 627 for 1 mole % Zn2+-doped NBT6BT. Although quenching from sintering tempera-tures has been recently touted to enhance T F-R, with quenching the doped composi- tions featuring an additional increase in T F-R by 17 °C, it exhibits negligible effect on the electromechanical properties. The effect is rationalized considering the missing influence on conductivity and therefore, negligible changes in the defect chemistry upon quenching. High-resolution diffraction indicates that Zn 2+-doped samples favor the tetragonal phase with enhanced lattice distortion, further corroborated by 23Na Nuclear Magnetic Resonance investigations.

Binary transition-metal oxides (BTMOs) with hierarchical micro-nano-structures have attracted great interest as potential anode materials for lithium-ion batteries (LIBs). Herein, we report the fabrication of hierarchical cauliflower-like CoFe2 O4 (cl-CoFe2 O4 ) via a facile room-temperature co-precipitation method followed by post-synthetic annealing. The obtained cauliflower structure is constructed by the assembly of microrods, which themselves are composed of small nanoparticles. Such hierarchical micro-nano-structure can promote fast ion transport and stable electrode-electrolyte interfaces. As a result, the cl-CoFe2 O4 can deliver a high specific capacity (1019.9 mAh g-1 at 0.1 A g-1 ), excellent rate capability (626.0 mAh g-1 at 5 A g-1 ), and good cyclability (675.4 mAh g-1 at 4 A g-1 for over 400 cycles) as an anode material for LIBs. Even at low temperatures of 0 °C and -25 °C, the cl-CoFe2 O4 anode can deliver high capacities of 907.5 and 664.5 mAh g-1 at 100 mA g-1 , respectively, indicating its wide operating temperature. More importantly, the full-cell assembled with a commercial LiFePO4 cathode exhibits a high rate performance (214.2 mAh g-1 at 5000 mA g-1 ) and an impressive cycling performance (612.7 mAh g-1 over 140 cycles at 300 mA g-1 ) in the voltage range of 0.5-3.6 V. Kinetic analysis reveals that the electrochemical performance of cl-CoFe2 O4 is dominated by pseudocapacitive behavior, leading to fast Li+ insertion/extraction and good cycling life.

The past decade has observed rapid growth in the development of cobalt-free perovskite cathodes, which provide enhanced structure and operational stability at the operating temperature of intermediate temperature solid oxide fuel cells (IT-SOFC, 600–800 °C) compared to its cobalt-containing counterpart. This Review aims to present a comprehensive overview on the status and advances of the existing cobalt-free perovskite cathodes for IT-SOFCs by discussing electrochemical behaviors, thermal expansion properties, stabilities as well as the oxygen ionic and the electronic transport properties of these cobalt-free perovskite cathode compositions, with primary emphasis on the relationship between the electrochemical performances and the materials science-related factors. Among various cobalt-free perovskite cathodes presented in this Review, niobium-doped compositions generally show lower polarization resistances relative to other cathode compositions.

Over the past decade, solid‐state thermal control devices have emerged as potential candidates for enhanced thermal management and storage. They distinguish themselves from traditional passive thermal management devices in that their thermal properties have sharp, nonlinear dependencies on direction and operating temperature, and can lead to more efficient circuits and energy conversion systems than what is possible today. They also distinguish themselves from traditional active thermal management devices (e.g., fans) in that they have no moving parts and are compact and reliable. In this article, the recent progress in the four broad categories of solid‐state thermal control devices that are under active research is reviewed: diodes, switches, regulators, and transistors. For each class of device, the operation principle, material choices, as well as metrics to compare and contrast performance are discussed. New architectures that are explored theoretically, but not experimentally demonstrated, are also discussed.

Monolithic integration of III–V materials and devices on CMOS compatible on‐axis Si (001) substrates enables a route of low‐cost and high‐density Si‐based photonic integrated circuits. Inversion boundaries (IBs) are defects that arise from the interface between III–V materials and Si, which makes it almost impossible to produce high‐quality III–V devices on Si. In this paper, a novel technique to achieve IB‐free GaAs monolithically grown on on‐axis Si (001) substrates by realizing the alternating straight and meandering single atomic steps on Si surface has been demonstrated without the use of double Si atomic steps, which was previously believed to be the key for IB‐free III–V growth on Si. The periodic straight and meandering single atomic steps on Si surface are results of high‐temperature annealing of Si buffer layer. Furthermore, an electronically pumped quantum‐dot laser has been demonstrated on this IB‐free GaAs/Si platform with a maximum operating temperature of 120 °C. These results can be a major step towards monolithic integration of III–V materials and devices with the mature CMOS technology.

Polymer‐based solid‐state electrolytes are shown to be highly promising for realizing low‐cost, high‐capacity, and safe Li batteries. One major challenge for polymer solid‐state batteries is the relatively high operating temperature (60–80 °C), which means operating such batteries will require significant ramp up time due to heating. On the other hand, as polymer electrolytes are poor thermal conductors, thermal variation across the polymer electrolyte can lead to nonuniformity in ionic conductivity. This can be highly detrimental to lithium deposition and may result in dendrite formation. Here, a polyethylene oxide‐based electrolyte with improved thermal responses is developed by incorporating 2D boron nitride (BN) nanoflakes. The results show that the BN additive also enhances ionic and mechanical properties of the electrolyte. More uniform Li stripping/deposition and reversible cathode reactions are achieved, which in turn enable all‐solid‐state lithium–sulfur cells with superior performances., A boron nitride (BN) incorporated solid polymer electrolyte is developed with improved ionic conductivity, thermal responses, and mechanical properties for the application of all‐solid‐state Li–S batteries. The thermal and current uniformity derived from BN additive leads to a uniform Li deposition and preferred S conversion. Thus, an all‐solid‐state Li–S battery is successfully demonstrated with outstanding electrochemical performances.

This work aims to make a comparative analysis on the unbalanced discharging phenomenon for the battery packs with series/parallel configurations due to the temperature difference among the cells. A theoretically-based model is developed for the battery pack and the constant power discharging processes are simulated by the model. At the constant temperature difference, lowering operating temperature increases the divergence among the cell terminal voltages for the series pack and the cell discharging currents for the parallel pack. Increasing the temperature differences decreases the dischargeable energy of the series battery pack, while it affects little on that of the parallel. At the same temperature difference, the cell energy differences within the parallel battery pack are 5~10 times higher than that within the series, which makes the temperature uniformity claim of the parallel battery pack is higher than that of the series.

We investigated the characteristics and limitations in the event of hydrofluoric acid (HF) leakage by comparing and analyzing the offsite consequence analysis (OCA) tools based on the chemical plant operating conditions. We reviewed the tools Korea Offsite Risk Assessment (KORA) from South Korea and Risk Management Plan*Comp (RMP*Comp™) and Areal Location of Hazardous Atmospheres (ALOHA) from the United States. The scenario studied was based on a leak event from a 50% HF aqueous solution storage tank, and the operating conditions taken into consideration were the operating temperature and dike installation conditions. The results from the OCA differed; KORA presented a smaller range of offsite impact than did ALOHA. The offsite impact ranges of KORA and ALOHA increased as the operating temperature and dike installation area increased. However, RMP*Comp differed greatly in its offsite impact range results in the operating temperature range of 25 °C to 30 °C. Moreover, in the alternative scenario, a limitation existed in that the offsite impact range was not changed by the dike installation conditions. The offsite impact range analyzed via KORA and ALOHA reflected the reality of an HF leak accident better than that analyzed via RMP*Comp. Therefore, it is more reasonable to use KORA and ALOHA instead of RMP*Comp in OCA. Moreover, users should realize that ALOHA has a somewhat wider range of offsite impact than KORA does in OCA. The separation distance from the storage tank when installing a dike is effective between 1 and 1.5 m in consideration of securing the minimum workspace for workers. Integr Environ Assess Manag 2018;14:205-211. © 2017 SETAC.

The detection and monitoring of nitrogen dioxide (NO2) plays a vital role in the environmental, healthcare, farming, and industrial sectors. However, the development of NO2 gas sensors with simultaneously high sensitivity, reversibility, low detection limit, and excellent selectivity remains challenging. In this work, an ultrasensitive NO2 gas sensor with superb selectivity and reversibility is demonstrated based on α-phase molybdenum trioxide (α-MoO3). Nanoribbons of α-MoO3 are synthesized via vapor phase transport (VPT) and systematically characterized using a combination of advanced characterization probes. At an optimal operating temperature of 125 °C, the α-MoO3-based sensor shows a very high sensitivity toward NO2 with a detection limit as low as 24 ppb, while also exhibiting excellent selectivity and reversibility. Such impressive performance originates from the layered nature of the α-MoO3 nanoribbons as well as the hierarchical assembly of the nanoribbons as the sensing layer. The study demonstrates a facile sensing platform based on α-MoO3 for ultrasensitive and selective NO2 gas sensing.

The operating temperatures of commercial lithium‐ion batteries (LIBs) are generally restricted to a narrow range of −20 to 55 °C because the electrolyte is composed of highly volatile and flammable organic solvents and thermally unstable salts. Herein, the use of concentrated electrolytes is proposed to widen the operating temperature to −20 to 100 °C. It is demonstrated that a 4.0 mol L−1 LiN(SO2F)2/dimethyl carbonate electrolyte enables the stable charge–discharge cycling of a graphite anode and a high‐capacity LiNi0.6Co0.2Mn0.2O2 cathode and the corresponding full cell in a wide temperature range from −20 to 100 °C owing to the highly thermal stable solvation structure of the concentrated electrolyte together with the robust and Li+‐conductive passivation interphase it offered that alleviate various challenges at high temperatures. This work demonstrates the potential for the development of safe LIBs without the need for bulky and heavy thermal management systems, thus significantly increasing the overall energy density., Owing to the highly stable solvation structure, concentrated electrolyte enables the stable operation of LiNi0.6Co0.2Mn0.2O2|graphite full cells in a wide temperature range from −20 to 100 °C, which alleviates various challenges faced by commercial dilute electrolytes. This study demonstrates the potential to build a safe battery system without the bulky and heavy thermal management system, thus significantly increasing the overall energy density.

The fuel cell system is modeled to investigate output factors including voltage, power, and system efficiency for various input elements including different fuel composition, the air and fuel temperature and their utilization ratios. The purpose of this study is to examine the proficiency of a tubular solid oxide fuel cell (SOFC) by simplification in modeling calculation which results in the minimum required data. An electrochemical model is defined at first, and different current losses types were calculated in the next step. In further papers the amount of air and fuel is known and in some of them operating temperature must be known. But in this study it is enough to know the current density and required generated power of the SOFC. Since the amount of reacted methane is almost equal to input value, after performing this calculation for several fuel cells and validating it, the most optimal value for methane output is evaluated and output parameters of SOFC are calculated, then results are validated. The effect of main factors, including system temperature, pressure, current density, air and fuel flow rates and air to fuel ratio on the SOFC efficiency, were studied. Modeling method of current study provides optimum air and fuel flow rate.

The current study aims to investigate the simultaneous effects of a novel magnetic demulsifier concentration as well as operating temperature on the demulsification efficiency of three different aboriginal samples of Persian Gulf, namely, light, medium, and heavy crudes. In this regard, TOMAC-Fe3O4-SiO2 (MT) was chosen as the magnetic nano-modified demulsifier. The optimum concentrations of MT were obtained to be 0.98, 0.99, and 1.1 ppm, while the optimum operating temperatures determined were 38.2, 45.2, and 50.1 °C, corresponding to a demulsification efficiency of 95%, 88%, and 81% at the optimum temperature and optimum concentration of MT for light, medium, and heavy crude oil, respectively. Finally, using the obtained experimental data, empirical correlations were proposed for the first time to correlate the nano-modified demulsifier concentration and operating temperature to the demulsification efficiency for the three studied types of crude oil with different American Petroleum Institute degrees. © 2017 Curtin University and John Wiley & Sons, Ltd.

In this work, the anode of an MFC was innoculated using recycled activated sludge and incubated at 25 °C (start-up temperature, denoted as 25°Cstu) for 2 weeks, and the temperature was then stepwise changed to 35 °C, 25 °C, 45 °C, and 25 °C. A maximum power density of 54 mW/m2 and current density of 348 mA/m2 were observed at 25 °Cstu. The MFC performances at 35 °C and 45 °C were much lower compared to 25 °Cstu, due to substrate limitations. After operation at 35 °C (11 days) and 45 °C (9 days), the temperature was switched back to the initial temperature of 25 °C, though the MFC performance did not recover to the initial level for 25 °Cstu. These results confirm that after MFC stabilization at a start-up temperature, the increase of MFC operating temperature could lead to a failure of the MFC system, indicating that the operating temperature of an MFC system for wastewater treatment should be stable and remain as identical to its start-up temperature as possible.

Solid oxide fuel cell (SOFC) applications require lifetimes of several years on the system level. A big challenge is to demonstrate such exceptionally long lifetimes in ongoing R&D projects. Accelerated or compressed testing are alternative methods to obtain this. Activities in this area have been carried out without arriving at a generally accepted methodology. This is mainly due to the complexity of degradation mechanisms on the single SOFC components as function of operating parameters. In this study, we present a detailed analysis of approx. 180 durability tests regarding degradation of single SOFC components as function of operating conditions. Electrochemical impedance data were collected on the fresh and long-term tested SOFCs and used to de-convolute the individual losses of single SOFC cell components – electrolyte, cathode and anode. The main findings include a time-dependent effect on degradation rates and the domination of anode degradation for the evaluated cell types and operating conditions. Specifically, the steam content as determined by fuel inlet composition, current density and fuel utilization was identified as major parameter, more important than for example operating temperature. The obtained knowledge is adopted to identify optimal operation profiles in order to acquire accelerated testing for lifetime investigation of SOFCs.

In order to assess the influence of the operating temperature on the dielectric properties of recycled Polyethylene Terephthalate (PET) and Polyethylene Naphthalate (PEN) reinforced with inorganic fillers, a dielectric and thermal investigation was undertaken. Specimens were thermally aged at several temperatures between 90 and 200°C for 360 h. The effect of thermal aging time on dielectric and thermal properties was also investigated. The dielectric response and breakdown strength properties were evaluated. Differential scanning calorimetry (DSC) measurements showed that the degree of crystallinity and the glass transition temperature increased with aging temperature and duration. The data obtained showed that these materials exhibited a good resistance to thermal aging at temperatures below 140°C. Furthermore, it was found that the dielectric strength of the recycled PET and PEN and their composites decreased considerably for temperatures of over 170°C. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers

To explore the application of chemical-looping combustion (CLC) to the distributed medium- small-scale hot water and steam gas-fueled boilers, a CLC process based on two fixed bed reactors (FBRs) has been proposed. A Cu-Fe-based oxygen carrier (OC) was studied to meet the requirements for this process. Results showed that Cu30-Fe50/Al20 was exothermic both in the reduction step and in the oxidation step, and showed a quite large operating temperature window of 600–900°C. At the lower temperature side, it showed good low temperature reactivity, and at the higher temperature side, it showed strong resistance to carbon deposition, agglomeration, and sintering. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.

The Ag2Mo2O7 and Ag6Mo10O33 ceramics for ultra-low temperature co-fired ceramic application were prepared by the solid-state reaction route. The optimized densification temperatures of Ag2Mo2O7 and Ag6Mo10O33 are 460°C and 500°C, respectively. The phase structures and microstructures of these ceramics were systematically studied. The Ag2Mo2O7 ceramic sintered at 460°C/4 h exhibits excellent microwave dielectric properties with er=13.3, Q×f=25 300 GHz and τf=−142 ppm/°C at 9.25 GHz. The Ag6Mo10O33 ceramic sintered at 500°C/4 h shows the microwave dielectric properties with er=14.0, Q×f=8500 GHz and τf=−50 ppm/°C at 9.00 GHz. Moreover, when Ag2Mo2O7 samples are sintered at ultra-low sintering temperatures of 420°C-490°C, the Q×f values of them are all above 20 000 GHz. Besides, the Ag2Mo2O7 ceramic does not react with silver powder or aluminum powder. The variation of relative permittivity, resonant frequency, and Q×f values as a function of operating temperature has been also studied. All the results indicate that the Ag2Mo2O7 ceramic is a good candidate for ultra-low temperature co-fired microwave devices.

During fluidized bed biomass gasification, complex gas-solid mixing patterns and numerous chemical and physical phenomena make identification of optimal operating conditions challenging. In this work, a parametric experimental campaign was carried out alongside the development of a coupled reactor network model (CRNM) which successfully integrates the individually validated sub-models to predict steady-state reactor performance metrics and outputs. The experiments utilized an integrated gasification system consisting of an externally-heated, bench-scale, 4-inch, 5kWth, fluidized bed steam/air blown gasifier fed with woody biomass equipped with a molecular beam mass spectrometer (MBMS) to directly measure tar species. The operating temperature (750-850 ○C) and air/fuel equivalence ratio (ER=0-0.157) were independently varied in order to isolate their effects. Elevating temperature is shown to improve the char gasification rate and reduce tar concentrations. Air strongly impacts the composition of tar, accelerating the conversion of lighter polycyclic-aromatic hydrocarbons into soot precursors, while also improving the overall carbon conversion. This article is protected by copyright. All rights reserved.

India is implementing one of the world's largest solar PV program. For better performance assessment of large PV installations, module temperature plays an important role. Estimation of power generation in hot climatic countries like India can be improved by the use of appropriate module temperature correlation. The accuracy of module temperature correlations has been observed to be related with climatic conditions. In this work, different explicit and implicit correlations have been evaluated in different temperature ranges based on frequency of occurrence of three very different technology PV modules: amorphous silicon, hetero‐junction intrinsic thin layer, and multicrystalline silicon at Indian site. Results show that Faiman correlation is most efficacious for all technology PV modules under highest frequency of occurrence temperature range. It has been observed that accuracy of correlations decreases from low module temperature range toward high module temperature range for all technology PV modules, except in case of Faiman correlation. In case of multicrystalline silicon, which is most widely used technology, the variation in accuracy of correlations was highest. This frequency of occurrence‐based comparison of correlation's accuracy is efficient and beneficial for better performance assessment of PV systems, especially in Indian context due to its large solar mission.

Negative differential resistance (NDR), which describes the current decrease as the applied bias increases, holds great potential for varieties of electronic applications including radio-frequency oscillators, multipliers, and multivalue logics. Here, the modulation of a unique NDR effect in ambipolar black phosphorus (BP) transistors is reported, which is activated by specific electrical field dependence of lateral carrier distribution and is distinct from conventional NDR devices that rely on quantum tunneling. The NDR device exhibits a high peak current density (34 µA µm-1 ) and a high operating temperature. More importantly, due to the strong coupling between the channel and the gate electrode, both the NDR peak current and peak/valley voltages can be effectively modulated by the electrostatic gate. Furthermore, it is demonstrated that light can serve as an additional terminal for NDR modulation. The findings could provide an important insight into the transport behavior of BP transistors and contribute to the design of ambipolar-semiconductor-based electrical circuits.

“Zero-pressure” elimination with Pirani principle for vacuum measurement and increase of the measurement range limit of thermal gas-sensors and flow sensors Measurement of pressure in the medium vacuum range has been done via thermal conductivity. The literature on the Pirani principle has defined a lower range limit — the so-called “zero pressure” until now [1]. The minimum power needed to hold a sensor up to operating temperature exceeds the useful signal, due to the conductivity of the sensor mounting and the resulting heat loss through the suspension. The author was able to eliminate the “zero pressure”, thereby expanding the measurement range of Pirani sensors significantly downwards. Measurement results confirmed an extension of the measurement range of two decades downwards with the coiled Pirani. Also with other sensors that use thermal conductivity and heatentrainment effects, e.g. gas sensors and sensors for flow measurement, the new principle can be applied and thus lower the lower range limit.

Dual-junction GaAs laser power converters optimized for one monochromatic wavelength are presented, and their temperature dependence is experimentally evaluated. External quantum efficiency and irradiance-dependent current–voltage measurements (10 to 104 W/cm2) under monochromatic laser light (809 nm) have been undertaken to quantify temperature- and irradiance-dependent effects on the performance. The temperature dependence of the current matching of the two subcells, caused by the temperature-dependent absorbance, is quantified. Losses in performance due to variations in operating temperature for different power-by-light applications are calculated to be between 16.2% and 21.0%. Future potential enhancements in cell performance are discussed. For elevated temperatures, super-linear behavior of the spectral response with increasing irradiance is observed, which is attributed to effective luminescent coupling from the top to the bottom subcell as the device becomes more radiative limited. For low temperatures, where the bottom cell is overproducing, no dependence on irradiance is found, which shows the influence of photon transport losses to the substrate. © 2016 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd.

The present investigation focuses on the separation of phenanthrene (a polyaromatic hydrocarbon) from n-tetradecane (model diesel composition) via pervaporation using a fabricated aromatic polyimide membrane. The experiments demonstrate preferential permeation of the polyaromatic for all films within the studied experimental range. The influence of operating temperature, membrane pretreatment time, membrane composition, and membrane thickness on the pervaporative performance were investigated. Statistical software Design Expert 7.1.4 was used to derive the regression equation describing the effect of the above mentioned factors on the pervaporation separation index. These factors are optimized using response surface methodology. The highest value of pervaporation separation index obtained is 1.5277 kg m−2 h−1 and the corresponding optimized condition is: operating temperature 493 K, pretreatment time 16.55 h with a membrane composition of 2.76 wt% of phenanthrene in polyamic acid and thickness 53.22 µm. POLYM. ENG. SCI., 57:392–402, 2017. © 2016 Society of Plastics Engineers

Flexible electronics with highly thermal stability and mechanical strength are highly needed in advanced transportation systems. Semiconducting single-walled carbon nanotubes are one of the leading active materials for such thin film transistors because they are printable, flexible, thermally stable, and mechanically strong. Dielectrics with large capacitance are another major component, and polymer electrolytes are printed for flexible electronics, but they suffer from poor mechanical strength and low operating temperature. Here, a transparent, mechanically flexible, and thermally stable polyfluorinated electrolyte (PFE) is developed with high capacitance by curing printed polyfluorinated resin (PFR) and ionic liquid composite at high temperature. PFE inherits the mechanical flexibility and thermal stability from PFR. The immobilized ionic liquid inside the porous structures of PFE accounts for the high capacitance. With top-gated PFE, fully printed electronically pure single-chirality (6,5) single-walled carbon nanotube (SWCNT) thin-film transistors (TFTs) exhibit air stable, consistent, and reliable ambipolar characteristics with high transconductance (1 mS) and small subthreshold swing ( 105 ON/OFF current ratio for both carriers under low operation voltage.

The formation mechanism of ammonium bisulfate (ABS) in the process of SCR flue gas denitrification and some research progresses on ABS are reviewed in the paper. The main factors affecting the formation of ABS are investigated, the formation temperature of ABS is in the range of about 190°C−240°C; ABS exists in vapor phase at temperature between 320°C and 345°C, and begins to decompose when the temperature is higher than 345°C; the formation of the ABS can be reduced by reducing the amount of NH3 slip and SO3, in the flue gas. The adverse effects of ABS on catalyst and air preheater are discussed: ABS will cover the surface of catalyst and Bronsted acid sites, decreasing denitrification efficiency; it will deposit in the air preheater, fouling and corroding the air preheater and reduce its operational effectiveness; it also can reduce the resistivity of fly ash and the quality of the fly ash as well. The methods to control ABS formation and the measures to reduce its negative effects are proposed: Select appropriate operating temperature to reduce the ABS deposition over the SCR catalyst; replace the material of the air preheater components from steel to ceramic coating type and change the structure of the air preheater; Take proper methods to reduce NH3 slip and the oxidation rate of SO2, etc. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1664–1672, 2016

BACKGROUND: Microbial electrosynthesis (MES), a process by which microorganisms reduce carbon dioxide to multi‐carbon compounds using electrical current as energy source, has so far been demonstrated at temperatures ranging from 25 °C to 37 °C. Elevated operating temperatures, however, could improve overall performance and product recovery. Here the effect of temperature on MES by the acetogenic thermophiles Moorella thermoacetica and Moorella thermoautotrophica is investigated. RESULTS: Experiments were performed at operating temperatures ranging from 25 °C to 70 °C to determine the optimum operating temperature for MES. Optimal performance was observed to be close to the optimum growth temperatures reported for these strains. Production rate and activation energy of acetate at 60 °C was 6.9 ± 0.6 mM m⁻² d⁻¹ and 45.1 ± 3.8 kJ mol⁻¹ for M. thermoacetica and 11.6 ± 0.9 mM m⁻² d⁻¹ and 58.9 ± 2.5 kJ mol⁻¹ for M. thermoautotrophica with columbic efficiencies (CE) of 79 ± 15% and 72 ± 4%, respectively. CONCLUSION: Considering CE and acetate production rate during MES, M. thermoautotrophica outperformed M. thermoacetica over a wide range of operating temperatures. Current‐dependent reduction of CO₂ also occurred below the minimum growth temperature of these strains, suggesting that MES is non‐growth associated. © 2016 Society of Chemical Industry

This article established a new electrical system structure-solid oxide fuel cell (SOFC) and proton exchange membrane fuel cell (PEMFC) hybrid power generation system. In this system, a high-temperature SOFC not only is used to produce electricity but also supply the reformed gas to a PEMFC to generate extra electricity simultaneously. A steady-state thermodynamic model of the SOFC-PEMFC hybrid system is established based on the mass and energy balance and the electrochemistry theory. The performance analysis demonstrates that for a 200 kW system, the lower heating value (LHV)-based electricity efficiency and overall efficiency (sum of the electricity and thermal efficiencies) predicted for the hybrid system are 60% and 90%, respectively, which are better than the SOFC-only system and the reformer-PEM system at similar output power. A parametric study is carried out to study the effects of the SOFC hydrogen utilization, the SOFC operating temperature, steam to carbon ratio and operating pressure on the performance of the hybrid system. The results show that the SOFC operating temperature and the steam to carbon ratio have positive impact on the power output and overall efficiency of the system. The operating pressure benefits the system power output but not for the overall efficiency. Moreover, there is an optimum SOFC fuel utilization factor at the highest value of the power output and overall efficiency of the hybrid system.

A large energy input for preheating and recovering of high excess alcohols used are the main issue in the supercritical methanol (SCM) process. This work demonstrated the production of biofuel from used palm olein oil in SCM using a low methanol to oil molar ratio. The effects of the operating temperature (350–400 °C), methanol to oil molar ratio (9:1–12:1), and reaction time (2–10 min), and their reciprocal interactions were evaluated using a central composite design. The optimum process conditions were determined to be a temperature of 395 °C, methanol to oil molar ratio of 12:1, and reaction time of approximately 9 min through the use of response surface methodology. The modified quadratic regression model demonstrated that the triglyceride conversion (%XTG) and methyl ester content (%FAME) were sensitive to changes in the operating temperature and reaction time, while the effect of the methanol to oil molar ratio was minimal. Under the optimal operating conditions, the predicted values of %XTG and %FAME were 100% and 63.67%, respectively, which were in good agreement with the experimental values. The fuel properties of biofuel obtained from optimal conditions were examined and then compared to American and European standards for biodiesel. © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.

Development of high-performance p-type semiconductor based gas sensors exhibiting fast-response/recovery times with ultra-high response are of major importance for gas sensing applications. Recent reports demonstrated the excellent properties of p-type semiconducting oxide for various practical applications, especially for selective oxidation of volatile organic compounds (VOCs). In this work, sensors based on CuO nanowire (NW) networks have been successfully fabricated via a simple thermal oxidation process on pre-patterned Au/Cr pads. Our investigation demonstrates high impact of the process temperature on aspect ratio and density of copper oxide NWs. An optimal temperature for growth of thin and densely packed NWs was found to be at 425 degrees C. The fabricated sensors demonstrated ultra-high gas response by a factor of 313 to ethanol vapour (100 ppm) at an operating temperature of 250 degrees C. High stability and repeatability of these sensors indicate the efficiency of p-type oxide based gas sensors for selective detection of VOCs. A high-performance nanodevice was fabricated in a FIB-SEM system using a single CuO NW, demonstrating an ethanol response of 202 and rapid response and recovery of similar to 198 ms at room temperature. The involved gas sensing mechanism of CuO NW networks has been described. We consider that the presented results will be of a great interest for the development of higherperformance p-type semiconductor based sensors and bottomup nanotechnologies. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Semiconducting metal oxides-based gas sensors with the capability to detect trace gases at low operating temperatures are highly desired in applications such as wearable devices, trace pollutant detection, and exhaled breath analysis, but it still remains a great challenge to realize this goal. Herein, a multi-component co-assembly method in combination with pore engineering strategy is proposed. By using bi-functional (3-mercaptopropyl) trimethoxysilane (MPTMS) that can co-hydrolyze with transition metal salt and meanwhile coordinate with gold precursor during their co-assembly with PEO-b-PS copolymers, ordered mesoporous SiO2 -WO3 composites with highly dispersed Au nanoparticles of 5 nm (mesoporous SiO2 -WO3 /Au) are straightforward synthesized. This multi-component co-assembly process avoids the aggregation of Au nanoparticles and pore blocking in conventional post-loading method. Furthermore, through controlled etching treatment, a small portion of silica can be removed from the pore wall, resulting in mesoporous SiO2 -WO3 /Au with increased specific surface area (129 m2 g-1 ), significantly improved pore connectivity, and enlarged pore window (>4.3 nm). Thanks to the presence of well-confined Au nanoparticles and e-WO3 , the mesoporous SiO2 -WO3 /Au based gas sensors exhibit excellent sensing performance toward ethanol with high sensitivity (Ra /Rg = 2-14 to 50-250 ppb) at low operating temperature (150 °C).

Flexible electronics require its substrate to have adequate thermal stability, but current thermally stable polymer substrates are difficult to be disintegrated and recycled; hence, generate enormous electronic solid waste. Here, a thermally stable and green solvent-disintegrable polymer substrate is developed for flexible electronics to promote their recyclability and reduce solid waste generation. Thanks to the proper design of rigid backbones and rational adjustments of polar and bulky side groups, the polymer substrate exhibits excellent thermal and mechanical properties with thermal decomposition temperature (Td,5% ) of 430 °C, upper operating temperature of over 300 °C, coefficient of thermal expansion of 48 ppm K-1 , tensile strength of 103 MPa, and elastic modulus of 2.49 GPa. Furthermore, the substrate illustrates outstanding optical and dielectric properties with high transmittance of 91% and a low dielectric constant of 2.30. Additionally, it demonstrates remarkable chemical and flame resistance. A proof-of-concept flexible printed circuit device is fabricated with this substrate, which demonstrates outstanding mechanical-electrical stability. Most importantly, the substrate can be quickly disintegrated and recycled with alcohol. With outstanding thermally stable properties, accompanied by excellent recyclability, the substrate is particularly attractive for a wide range of electronics to reduce solid waste generation, and head toward flexible and "green" electronics.

High temperature brings adverse impacts on the energy efficiency, and even destroys a semiconductor device. Here, a novel and cost-effective strategy is proposed to boost the energy efficiency of semiconductor devices by using the self-adaptive evaporative cooling of a lithium- and bromine-enriched polyacrylamide hydrogel. Water inside the hydrogel can quickly evaporate to dissipate the waste heat generated by the nugatory carrier transport in the P-N junction. In dormancy, the hydrogel harvests water molecules from the surrounding air to regenerate itself. The hydrogel is demonstrated to low down the operating temperature of a commercial polycrystalline silicon solar cell by 17 °C under one sun condition and enhances its efficiency from 14.5% to 15.5%. It is also capable of increasing the maximum power of a simulated chip by 45% at a fixed operating temperature. The hydrogel is expected to be widely adopted in current semiconductor industry to improve its energy efficiency.