Passive radiation cooling（PRC）, as the most promising technology to meet future cooling needs, has attracted great interest. However, there are still huge challenges in manufacturing high-efficiency and low-cost rad...
详细信息
Passive radiation cooling（PRC）, as the most promising technology to meet future cooling needs, has attracted great interest. However, there are still huge challenges in manufacturing high-efficiency and low-cost radiant coolers suitable for all-day use. Here, we report a secondary micro-nano shell-hollow structure based on blending method, inspired by the African white beetle Goliathus goliatus. Due to the difference in reflectance between the shell and the internal air, compared with the homogeneous particles, the scattered light has a changed optical path at the interface of the core（air） and the shell（SiO2）, and most of the light escapes from the particles, showing strong total internal reflection. The design ingeniously deposits the nano-sized shell-hollow structure on the surface of the micron-sized shell-hollow structure, achieving high solar reflectance（95 %）and excellent long-wave infrared emissivity（94 %）. Sub-ambient cooling of 7.8 and 4.7°C can be achieved at night and daytime,respectively. Silica microspheres with shell and hollow structure can be prepared by soft template method, which is mature, reliable, simple and *** work provides new ideas for the design and manufacture of highperformance Passive all-day radiative cooling（PARC）.
Quality enhancement of the products and services provided by manufacturing enterprises is gaining more and more attention from researchers. This research work leads to the development and implementation of AHP-based m...
详细信息
The Design and manufacturing of a noble piezoresistive pressure sensor(PS) for subtle pressures(<1 kPa) were presented. Meanwhile, in the studies conducted in the field of pressure sensors, the measurement of subtl...
详细信息
The Design and manufacturing of a noble piezoresistive pressure sensor(PS) for subtle pressures(<1 kPa) were presented. Meanwhile, in the studies conducted in the field of pressure sensors, the measurement of subtle pressures has received less attention. The limitations in the inherent gauge factor in silicon, have led to the development of polymer and composite resistive sensitive elements. However,in the development of resistance sensing elements, the structure of composite elements with reinforcement core has not been used. The proposed PS had a composite sandwich structure consisting of a nanocomposite graphene layer covered by layers of PDMS at the bottom and on the top coupled with a polyimide(PI) core. Various tests were performed to analyze the PS. The primary design target was improved sensitivity, with a finite-element method(FEM) utilized to simulate the stress profile over piezoresistive elements and membrane deflection at various pressures. The PS manufacturing process is based on Laser-engraved graphene(LEG) technology and PDMS casting. Experimental data indicated that the manufactured PS exhibits a sensitivity of 67.28 mV/kPa for a pressure range of 30-300 Pa in ambient temperature.
Mini-channel heatsinks are one of the most effective thermal management methods for high heatflux devices due to the high performance of convective heat *** recent years,various techniques have been innovated to impro...
详细信息
Mini-channel heatsinks are one of the most effective thermal management methods for high heatflux devices due to the high performance of convective heat *** recent years,various techniques have been innovated to improve the thermal proficiency of the mini-channel *** of these are taking advantage offins’structural designs and ar-rangements of inlets and *** zigzagfins and channels were considered in the previous works in heatsinks,and researchers analyzed their cooling enhancement ***,in the present work,a combined cooling technique,considering new-type zigzagfins’geometrical parameters(arrangement,length,and height)causes turbulenceflow and higher convective heat transfer along with different positionings offlow inlet and outlets resulting in superior temper-ature uniformity,is proposed to evaluate their impacts on the cooling proficiency of the heat sink versus different Reynolds *** assess the thermal and hydraulic performance of the proposed heatsink,different parameters,including temperature contours,Nusselt numbers,thermal resistance,and entropy generation are *** a result,it is observed that in the case demonstrating the best thermal performance,the Nusselt number,pressure drop,thermal resistance,and entropy generation are respectively 37.13,4586.46 Pa,0.000078 m^(2)·K/W,and 0.1078 W/K in the best *** well,it is found that by changing the arrangements of inlets and outlets,the Nusselt number,and thermal resistance are improved by 12%and 13%,***,the proposed mini-channel heat sink could be used as a high-performance thermal management system for electronic devices in different industries,including energy,solar,and medical sectors.
Present work investigates the heat transfer and melting behaviour of phase change material(PCM) in six enclosures(enclosure-1 to 6) filled with paraffin *** enclosures are equipped with distinct arrangements of the fi...
详细信息
Present work investigates the heat transfer and melting behaviour of phase change material(PCM) in six enclosures(enclosure-1 to 6) filled with paraffin *** enclosures are equipped with distinct arrangements of the fins while keeping the fin's surface area equal in each *** analysis has been presented to recognize the suitable fin arrangements that facilitate improved heat transfer and melting rate of the *** wall of the enclosure is maintained isothermal for the temperature values 335 K,350 K and 365 *** length of the enclosure including fins is ranging between 0 and *** have been illustrated through the estimation of important performance parameters such as energy absorbing capacity,melting rate,enhancement ratio,and Nusselt *** has been found that melting time(to melt 100% of the PCM) is 60.5%less in enclosure-2(with two fins of equal length) as compared to the enclosure-1,having no *** the fin surface area equal,if the longer fin is placed below the shorter fin(enclosure-3),melting time is further decreased by 14.1% as compared to ***,among all the configurations,enclosure-6 with wire-mesh fin structure exhibits minimum melting time which is 68.4% less as compared to the *** on the findings,it may be concluded that fins are the main driving agent in the enclosure to transfer the heat from heated wall to the *** design and positioning of the fins improve the heat transfer rate followed by melting of the PCM in the entire area of the *** of the favourable vortices and natural convection current in the enclosure accelerate the melting phenomenon and help to reduce charging time.
Forging is one of the techniques traditionally used in the manufacture of knee implants. As the material deforms, stress develops during forging. When these stresses exceed a threshold, it can render a product defecti...
详细信息
This study investigated the effects of zigzag-flow channel bending angle in printed circuit heat exchangers(PCHEs) using a computational fluid dynamics method with ANSYS-FLUENT *** three-dimensional model of PCHE with...
详细信息
This study investigated the effects of zigzag-flow channel bending angle in printed circuit heat exchangers(PCHEs) using a computational fluid dynamics method with ANSYS-FLUENT *** three-dimensional model of PCHE with a 15° curved,zigzag channel was conducted for preliminary *** comparisons between the CFD simulation results and the experimental data showed good agreement with some discrepancies in the heat transfer and pressure drop *** addition,different bending angle configurations(0°,3° to 30°) of zigzag channels were analyzed to obtain better thermal-hydraulic performance of the zigzag channel PCHE under different inlet mass flow *** criteria of heat transfer and frictional factor were applied to evaluate the thermal-hydraulic performance of the *** results showed that the 6° and 9°bending channel provided good thermal-hydraulic *** correlations were developed using the 6°and 9° bending channel angles in PCHE designs to predict the Nusselt number and friction factor.
A winding system is a time-varying system that considers complex nonlinear characteristics,and how to control the stability of the winding tension during the winding process is the primary problem that has hindered de...
详细信息
A winding system is a time-varying system that considers complex nonlinear characteristics,and how to control the stability of the winding tension during the winding process is the primary problem that has hindered development in this field in recent *** nonlinear factors affect the tension in the winding process,such as friction,structured uncertainties,unstructured uncertainties,and external *** terms severely restrict the tension tracking *** tension control strategies are mainly based on the composite control of the tension and speed loops,and previous studies involve complex decoupling *** to the large number of calculations required for this method,it is inconvenient for practical engineering *** simplify the tension generation mechanism and the influence of the nonlinear characteristics of the winding system,a simpler nonlinear dynamic model of the winding tension was *** adaptive method was applied to update the feedback gain of the continuous robust integral of the sign of the error(RISE).Furthermore,an extended state observer was used to estimate modeling errors and external *** model disturbance term can be compensated for in the designed RISE *** asymptotic stability of the system was proven according to the Lyapunov stability ***,a comparative analysis of the proposed nonlinear controller and several other controllers was *** results indicated that the control of the winding tension was significantly enhanced.
The purpose of this review is to explore the intersection of computational engineering and biomedical science,highlighting the transformative potential this convergence holds for innovation in healthcare and medical *...
详细信息
The purpose of this review is to explore the intersection of computational engineering and biomedical science,highlighting the transformative potential this convergence holds for innovation in healthcare and medical *** review covers key topics such as computational modelling,bioinformatics,machine learning in medical diagnostics,and the integration of wearable technology for real-time health *** findings indicate that computational models have significantly enhanced the understanding of complex biological systems,while machine learning algorithms have improved the accuracy of disease prediction and *** synergy between bioinformatics and computational techniques has led to breakthroughs in personalized medicine,enabling more precise treatment ***,the integration of wearable devices with advanced computational methods has opened new avenues for continuous health monitoring and early disease *** review emphasizes the need for interdisciplinary collaboration to further advance this *** research should focus on developing more robust and scalable computational models,enhancing data integration techniques,and addressing ethical considerations related to data privacy and *** fostering innovation at the intersection of these disciplines,the potential to revolutionize healthcare delivery and outcomes becomes increasingly attainable.
This study examines the wear and corrosion characteristics of Al7079 alloy matrix composites that are strengthened with boron nitride (BN) and aloe vera particles. These composites are produced using the stir casting ...
详细信息
暂无评论