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Optimization of optical current sensor based on rare-earth magneto-optical glass
摘要： Compared to the present diamagnetic glass used in the sensing element of optical current sensors (OCSs), the high-sensitivity characteristics of the rare-earth magneto-optical glass (REMOG) can significantly improve the performance of an REMOG sensing element. The optimization objective of this study was to enhance the sensitivity of the sensing element and reduce linear birefringence. Theoretical analysis and experimental data were combined to study the practical influences of a few factors, such as the size and spatial position of the glass, the wavelength of the incident light, and the rare-earth doping concentration, on the sensitivity of an OCS sensing element. Finally, an optimal parameter combination was obtained. The experimental results showed that the response sensitivity of the REMOG sensing element is seven times the sensitivity using diamagnetic glass.
关键词： sensitivity,paramagnetic material,optical current transformer
更新于2025-09-23 15:21:01
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Effects of laser surface melting on crystallographic texture, microstructure, elastic modulus and hardness of Tia??30Nba??4Sn alloy
摘要： The biocompatibility of orthopedic implants is closely related to their elastic modulus and surface properties. The objective of this study was to determine the effects of cold rolling, recrystallization and laser surface melting (LSM) on the microstructure and mechanical properties of a biphase (α″+β) Ti?30Nb?4Sn alloy. X-ray diffraction (XRD) texture analysis of the cold-rolled substrate revealed the [302]α″//ND texture component, while analysis of the recrystallized substrate showed the [302]α″//ND and [110]α″//ND components. The β-phase texture could not be directly measured by XRD, but the presence of the [111]β//ND texture component was successfully predicted by considering the orientation relationship between the α″ and β phases. Nanoindentation measurements showed that the elastic modulus of the cold-rolled substrate (63 GPa) was lower than that of the recrystallized substrate (74 GPa). Based on the available literature and the results presented here, it is suggested that this difference is caused by the introduction of crystal defects during cold deformation. The combined nanoindentation/EBSD analysis showed that the nanoindentation results are not affected by crystal orientation. LSM of the deformed alloy produced changes in hardness, elastic modulus and crystallographic texture similar to those produced by recrystallization heat treatment, creating a stiffness gradient between surface and substrate.
关键词： laser surface melting,stiffness-graded material,crystallographic texture,cold rolling,titanium alloy,recrystallization
更新于2025-09-23 15:21:01
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Exergy and energy analysis of wavy tubes photovoltaic-thermal systems using microencapsulated PCM nano-slurry coolant fluid
摘要： To develop a more efficient water-cooled photovoltaic-thermal system, energy and exergy analysis of a photovoltaic-thermal system with wavy tubes are investigated numerically using different coolant fluids. A comparison between the straight tube and wavy tubes is conducted for various wavelengths and wave amplitudes. The geometrical parameters of the wavy tubes as well as the velocity of the coolant fluid are examined. Besides, the consequences of coolant fluid including water, Ag/water nanofluid, microencapsulated phase change material slurry, and also a new type of cooling fluid called microencapsulated phase change material nano-slurry are studied. The results show that the electrical, thermal, and exergy efficiencies of the photovoltaic-thermal module enhance by using the wavy tubes compared with the corresponding straight tubes. By declining wavelength in a constant wavelength/amplitude, the heat absorbed by the heat transfer fluid raises. For the best configuration, the primary and exergy efficiencies of the module increase by 6.06% and 4.25%, respectively, for the wavy tubes system compared with those for the straight unit. Furthermore, in both configurations, by increasing the inlet velocity, the overall performance of the photovoltaic-thermal module increases due to a higher heat transfer rate. The results also reveal that among different types of cooling fluids, the microencapsulated phase change material nano-slurry has higher performance in terms of both energy and exergy efficiencies due to having higher thermal conductivity and heat capacity. By employing the wavy tube and the novel proposed coolant fluid, the primary and exergy efficiencies increase in comparison with a typical photovoltaic-thermal module.
关键词： Energy,Microencapsulated phase change material slurry,Wavy tube,Nanofluid,Photovoltaic-thermal module,Exergy
更新于2025-09-23 15:21:01
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Deep and high precision cutting of alumina ceramics by picosecond laser
摘要： Ceramics possess high thermal and chemical resistance, low density, and high compressive strength; however, the machining complications imposed by their inherent brittleness limit their range of applications. Laser cutting technology can offer an automated manufacturing technique for machining these brittle materials. In this paper, a laser cutting method, so-called wobbling, was developed for performing deep, high precision, and defect-free laser cutting of industrial grade alumina ceramics. This work explored picosecond laser process parameters such as focal position, linear speed, and wobble amplitude in order to control cut depth and optimize cut quality in terms of kerf width, kerf taper, surface cleanness, while avoiding crack formation. The morphology and cut quality were evaluated using 3D laser scanning microscopy and scanning electron microscopy (SEM). Picosecond laser cutting process parameters were optimized, achieving a maximum material removal rate of ~10 mm3/min. It was shown that the laser cutting process developed via these experiments represents an effective and efficient manufacturing tool that can be incorporated in engineered net shaping systems.
关键词： Laser cutting,Material removal rate,Ablation,Ultrafast laser micromachining,Alumina ceramics
更新于2025-09-23 15:21:01
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Experimental analysis of a photovoltaic/thermoelectric generator using cobalt oxide nanofluid and phase change material heat sink
摘要： Nowadays, photovoltaic panels have been known as effective devices to harness solar energy. These panels mainly convert the UV and visible areas of the solar spectrum into electricity and the rest of the energy is dissipated. One of the favorable methods to take advantage of such dissipated heat is to combine thermoelectric generators (TEG) utilizing the IR area of the solar radiation with photovoltaic panels. Having the different and opposite impact on the efficiency of thermal photovoltaic cells (PV/T) and thermoelectric generators (TEG), the system operating temperature appears as a critical parameter in the productivity of a PV/T-TEG hybrid unit. In the present study, a novel heat sink for a PV/T-TEG hybrid system is introduced. The effectiveness of simultaneous usage of the Co3O4/water nanofluid and the improved phase change material (paraffin wax/Alumina powder) as a cooling method on the performance of the PV/T-TEG is examined throughout an experimental study. Then, the overall electrical, thermal and exergy efficiency of such a system is compared to the units with divers working fluids including water and 0.25%, 0.5%, and 1% nanofluid and the unit consisting of 1% nanofluid with non-enhanced PCM cooling method. The results reveal that using 1% nanofluid with enhanced PCM, as a cooling method, would improve the overall electrical efficiency by 12.28% compared to water cooling technique. Also, an increase of 11.6% in the exergy efficiency of the PV/T-TEG is observed in comparison with PV/T-TEG with the water cooling method. Hence, it could be concluded that the combination of this unit could contribute to harnessing solar energy more efficiently, compared to solo photovoltaic panels.
关键词： Photovoltaic thermal,Solar energy,Nanofluid,Thermoelectric generator,Phase change material
更新于2025-09-23 15:21:01
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Experimental study for the application of different cooling techniques in photovoltaic (PV) panels
摘要： This article contains the experimental investigations of different cooling methods used for photovoltaic (PV) panels. Phase change material (PCM), thermoelectric (TE) and aluminum fins were chosen as the cooling methods. The CaCl2·6H2O is chosen as one of the PCM which is widely used in the cooling of PVs and the other is the PCM with melting temperature above the surface temperature of the PV panel. By using TE material in different numbers (6, 8 and 12) and aluminum fins in different layouts, surface temperatures and output powers of PV panels were compared. It is observed that the PCM which is not chosen appropriately has insulation feature in the PV panel and enhances the temperature of the panel and decreases the output power. When the most successful cooling methods were tested under the same environmental conditions, PV with fin system produced the highest power generation of 47.88 W while PV with PCM and TEM produced the lowest power generation of 44.26 W.
关键词： Thermoelectric module,Photovoltaic,Fin,Cooling,Phase change material
更新于2025-09-23 15:21:01
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Metal-Doped Copper Indium Disulfide Heterostructure: Environment-Friendly Hole-Transporting Material toward Photovoltaic Application in Organic-Inorganic Perovskite Solar Cell
摘要： In this plan, we use Praseodymium metal-doped copper indium disulfide (Pr-doped CIS) heterostructure as hole-transporting materials (HTMs) in the FTO/TiO2/Perovskite absorber/HTM/Au device. And photovoltaic performance of these Pr-doped CIS heterostructure was investigated in the fabrication of the organic-inorganic perovskite solar cells (organic-inorganic PSCs).
关键词： Pr-coated CuInS2 heterostructure,solar energy,perovskite solar cells,green electricity,hole-transporting material
更新于2025-09-23 15:21:01
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Laser-Induced Periodic Surface Structuring of Poly(trimethylene terephthalate) Films Containing Tungsten Disulfide Nanotubes
摘要： We report the study of the formation of Laser Induced Periodic Surface Structures (LIPSS), with UV femtosecond laser pulses (λ = 265 nm), in free-standing films of both Poly(trimethylene terephthalate) (PTT) and the composite PTT/tungsten disulfide inorganic nanotubes (PTT-WS2). We characterized the range of fluences and number of pulses necessary to induce LIPSS formation and measured the topography of the samples by Atomic Force Microscopy, the change in surface energy and contact angle using the sessile drop technique, and the modification in both Young’s modulus and adhesion force values with Peak Force-Quantitative Nanomechanical Mapping. LIPSS appeared parallel to the laser polarization with a period close to its wavelength in a narrow fluence and number of pulses regime, with PTT-WS2 needing slightly larger fluence than raw PTT due to its higher crystallinity and heat diffusion. Little change was found in the total surface energy of the samples, but there was a radical increase in the negative polar component (???). Besides, we measured small variations in the samples Young’s modulus after LIPSS formation whereas adhesion is reduced by a factor of four. This reduction, as well as the increase in ???, is a result of the modification of the surface chemistry, in particular a slight oxidation, during irradiation.
关键词： nanocomposites,ultrashort pulses,laser material processing,nanostructures,LIPSS
更新于2025-09-23 15:21:01
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Machine learning-optimized Tamm emitter for high-performance thermophotovoltaic system with detailed balance analysis
摘要： Light-matter interaction upon nanophotonic structures in the infrared wavelength has drew increasing attentions due to the extensive potential applications. Among them, thermophotovoltaic (TPV) systems can exhibit higher efficiency over the Shockley-Queisser limit due to the nanophotonic structure-enabled tunable narrowband thermal emission rather than the broadband incident spectrum. However, two long-standing issues remain formidable as bottlenecks for achieving better performances of TPV system. One is the competing role of the power density and the system efficiency of TPV system, and the other is the magnanimity possibilities of structures, configurations, dimensions, and materials of thermal emitters that disables the manual optimization of TPV system. Here, we attempt to achieve high-performance TPV system by employing the machine learning algorithm under the framework of material informatics. The power density and system efficiency are well modelled through the detailed balance analysis with full considering the photocurrent generation in the PV cells. Through optimization, the non-trial aperiodic Tamm emitters are obtained and the metal-side one is preferable in terms of the TPV performance. The present work is demonstrated to be feasible and efficient in optimizing the TPV performance, and opens a new door for the optimization problems in other fields.
关键词： Machine learning,Material informatics,Tamm emitter,Optimization,Thermophotovoltaics
更新于2025-09-23 15:21:01
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Fabrication and performance analysis of a low cost, Pt free counter electrode using carbon coated ZnAl layered double hydroxide (C/ZnAl-LDH) for dye sensitized solar cells
摘要： Carbon based material represents an e?ective substitute for Pt counter electrodes (CEs) in Dye Sensitized Solar Cells (DSSCs). This study introduces a novel carbon coated ZnAl layered double hydroxides (C/ZnAl-LDH) can be utilised as an e?ective CE in DSSCs. C/ZnAl-LDH was synthesised by the pyrolysis of ZnAl-LDH using glucose solution. The synthesised C/ZnAl-LDH was characterised using TEM, SEM, XRD and BET analysis. The surface roughness of both Pt and C/ZnAl-LDH ?lms were analysed using AFM spectroscopy. C/ZnAl-LDH slurry was pasted uniformly using doctor blade technique onto FTO glass substrate. The electrochemical measurements such as Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Tafel polarization recommends that C/ZnAl-LDH can be used as a CE due to its good reduction rate of ?I3 comparable with Pt CEs. The photovoltaic parameters were observed to be 0.66 V and 11.97 mA/cm2 for open circuit voltage V(oc) and short circuit current density J(sc) respectively for C/ZnAl-LDH CE. The assembled cell with C/ZnAl LDH CE having power conversion e?ciency (PCE) of 3.18% is comparable to Pt CE having 4.62% which is measured under the similar testing conditions.
关键词： Dye Sensitized Solar Cell,Carbon based material,Counter electrode,Layered double hydroxides,Electrochemical parameters
更新于2025-09-23 15:21:01