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Numerical Simulation and Performance Analysis of a Water-Based Photovoltaic/Thermal (PVT) Collector Using Simulink Environment
Get PDFThe hybrid photovoltaic-thermal (PVT) collector is an innovative technology that exploits solar energy to simultaneously generate electricity and heat. It thus optimizes the use of the surface exposed to sunlight by maximizing total energy production, offering a higher overall efficiency compared to standard thermal collectors or separately installed photovoltaic panels. In this research, a “sheet and tube” type water-based PVT collector was studied numerically. The main objective is to develop and analyze a hybrid PVT collector to optimize its overall efficiency. A mathematical model was developed for each component of the PVT collector (glass cover, PV module, absorber plate, tube, fluid, and insulation). Subsequently, the Hottel-Whillier thermal model was implemented and simulated in the Simulink/Matlab environment to study the collector’s performance. Furthermore, the effects of mass flow rate, number of glazings, inlet fluid temperature, and the heat transfer coefficient between the absorber plate and the PV module, among other operating parameters, were analyzed to identify their influence on electrical and thermal performance. A comparative analysis between PV and PVT collectors was conducted, and annual thermal and electrical energy productions were evaluated to assess the overall performance of each system
Recent Advances in Nanomaterial-Based Flexible Piezoresistive Sensors for Robotic Tactile Sensing
Get PDFThe expansion of industrial automation has underscored the critical role of robotic systems, where pressure sensors serve as essential interfaces for tactile feedback and precise manipulation. Flexible piezoresistive pressure sensors have become especially attractive because of their simple design, straightforward operation, and scalable fabrication. Recent progress in conductive nanomaterials such as carbon- and metal-based fillers, and engineered microstructures, including surface and porous designs in both single and hierarchical configurations, has significantly improved sensor sensitivity and broadened their operational range, demonstrating how material choice and structural engineering directly shape device performance. This review introduces the underlying physics of piezoresistivity and discusses the metrics commonly used to characterize sensor behavior, including sensitivity, gauge factor, and response time, before examining advances in nanomaterial integration and structural strategies that enable enhanced functionality. Applications highlight their integration into robotic fingertips and joints, where they provide force regulation, object recognition, and motion tracking, underscoring their importance in robotic control. Remaining challenges such as uniformity, reproducibility, and large-scale manufacturability continue to hinder widespread adoption, yet ongoing improvements in material systems and fabrication methods promise to address these limitations. Through the integration of material design, structural engineering, and performance evaluation, this work establishes a comprehensive link between fundamental principles and robotic applications, offering insights that can guide the development of next-generation tactile sensing technologies and opening pathways toward next-generation robotic systems empowered by highly sensitive and reliable pressure sensors
Photocatalytic MOF Membranes for Advanced Seawater Purification: From Material Design to Sustainable Water Treatment
Get PDFSeawater pollution remains a pressing global challenge, intensified by industrial discharges, agricultural runoff, and maritime activities. Conventional water treatment methods are often limited by high energy costs, insufficient selectivity, and the risk of secondary pollution. Metal-organic frameworks (MOFs), recognized for their tunable porosity and high surface areas, are emerging as promising materials for advanced water purification. The integration of photocatalytic properties into MOF membranes offers a significant advantage: the addition of self-cleaning functionality to the inherent separation process, paving the way for more energy-efficient purification. This review explores recent progress in photocatalytic MOF membranes for treating seawater, addressing the critical issues of water scarcity and marine pollution. It examines how these materials can be enhanced through strategies like ligand functionalization, heterostructure engineering, and metal ion doping to boost their performance against organic pollutants, heavy metals, and pathogens. The synthesis of MOFs is discussed, alongside the critical need to optimize their stability, light absorption, and charge separation efficiency. Key challenges such as membrane fouling, salt scaling, and long-term durability are analyzed, along with potential solutions through material design and process engineering. Recent advances confirm the potential of these membranes for revolutionary improvements in water technology, especially when combined with renewable energy sources, highlighting their role in promoting sustainable water management and providing innovative directions for the field
Experimental Investigation of Oil Film Variation in Finite Line Contact Under Intermittent Motion
Get PDFThe variation of oil film distribution in the line contact area of pin and disk was experimentally observed during a periodic intermittent motion. The study was conducted on a ball-disk optical interferometric test rig, with motion speed controlled by PLC programming. PAO40 oil was primarily used in the experiment, with the glass disk undergoing periodic motion of constant speed-deceleration-stop-acceleration, while the pin roller remained fixed. The results indicate that when the motion stops, a portion of the oil is entrapped in the center of the contact area. As the acceleration phase begins, this portion of the oil is gradually squeezed out of the contact area, and the oil film with lowest thickness at the entrance of the contact area moves towards the exit of the contact area, passing through the contact center. It can also be observed that during the entire process, an increase in speed increases the film thickness, while an increase in deceleration time, i.e., a decrease in deceleration, reduces the film thickness during the stop phase
Structures and Electronic Properties of Different ZnIn2S4/CuInS2 Interface: A First-Principles Study
Get PDFThis paper aims to explore the electronic and photoelectric properties of two-dimensional type I (straddle) heterojunctions by theoretical calculation, and to provide theoretical support for the design of novel optoelectronic devices. Several ZnIn2S4/CuInS2 two-dimensional type I heterojunctions with different terminations have been systematically investigated by density functional theory (DFT) combined with tight binding approximation. The results show that only two of these structures are stable. In these two stable structures, different chemical bonds and electron transfer directions are formed when different atoms are exposed at the interface. The calculation results of band structures show that both of these structures are two-dimensional type I heterojunctions. The calculation results of effective mass show that they have efficient carrier separation and transport characteristics. These properties indicate that these two heterostructures can be used in high-performance light-emitting devices and photoelectric sensors. This study provides a theoretical basis for the optimal design of new two-dimensional optoelectronic devices
Synthesis of the SUS 316L Powders with a Nano-Meso Bi-Modal Structure
Get PDFPure stainless steel (SUS 316L) powders with both a nano-grain and micro-structure were prepared using a mechanical milling process. The bimodal microstructure consists of a nano-grain with a size of 50 nm in the surface region and microstructure in the core of the particle. The nano-grain with a bcc structure at the surface and the microstructure of fcc in the core of the particles were prepared by milling at 150rpm for 9h, and those compositions were 14.39% for the nano structure and 85.61% for the micro structure, respectively. Spark plasma sintering (SPS) was carried out for the compaction of the powders. The compacts forming powders with a bi-modal structure have a mesoscopic structure
Clamping Connection between Flexible Electrodes and External Wires
Get PDFFlexible electrodes are widely applied to many fields such as sensor, flexible printed circuit board, photovoltaic cell, cell phone, digital camera, and liquid crystal display and so on. Aim at the connecting problem between flexible electrodes and external wires; the detachable clamping connection was firstly brought forward to solve the aim problem under normal temperature. And on the basis of such idea, the corresponding clamper was designed and fabricated further by mechanical procedures. Then verifying and comparing experiments were done and observed. Experiment results illustrate that the detachable clamping connection is correct and effective and that such connection could solve the aiming problem without high temperature welding procedure. And furthermore it’s also known that clamper doesn’t change the main characteristics of signal transmission. The detachable clamping connection is very useful and effective for the connection between flexible thin film conductor and common wires when they can not be directly welded together under high temperature
Design and Development of a Simple Stirred Tank Photobioreactor for Algal Production
Get PDFA simple and efficient stirred tank photobioreactor was designed and developed for micro algal culture. The culture system was made of glass and consists of four major parts: culture system container, stirrer, aerator rod and aerator pump. The reactor had proved to be well suited for the cultivation of micro alga Chlorella sp. Two different trials were run for microalgal culture. The lux intensity at the photobioreactor was maintained at 200lux. The algal biomass volumetric output rate was 5.85g l-1 d-1
Assessment Tests for Digital Skills: A Tool for Learning Outcomes and University Accreditation
Get PDFAn important question asked by academicians is whether students use Internet languages constructively to further themselves in their chosen field of study while in college, or merely use them for social networking and entertainment.
The iSkills Test is a possible tool for assessment of students’ skills in using digital technology on the Internet. This paper seeks to investigate the test’s usefulness in helping to answer the question stated above and in the process, add positively to the reaffirmation of accredited universities where these students are enrolled.
An original method has been shown to allow instructors/coaches and institutions to assess the effectiveness of their programs through the use of this test, even though the grading scheme has been changed between the initial and final assessment tests (in one term). The grading code of the iCritical Thinking Certification test (now updated as the iSkills test) has been found, at least for the present.
After two years of testing data at the University of Miami, the University has been provided with three major strengths and three major weaknesses of the students. The undergraduate strengths are (1) shopping, (2) following directions, (3) using information ethically. The students’ weaknesses are (1) selecting resources, (2) researching, (3) knowing or understanding what they find. It is apparent that the areas of weaknesses are areas of opportunity for the University to improve their students’ digital skills. Some useful suggestions have been developed to help students improve their critical thinking abilities and thus perform better in the certification test.
The iSkills tests involved organization of information, development of a search strategy, creating a slide, summarize researched information, creating a visual representation and constructing an advanced search. These tasks involved a variety of skill sets and they mimic real world tasks. This test is recommended for the assessment by universities of their students’ improvement in digital skills development while on the Internet, across the disciplines. The tests are used to help convince university accreditation bodies like Southern Association of Colleges and Schools in the U.S.A. International acceptance of the test is recommended since the use of the Internet is global, and digital skills development is an undeniably important asset
Virtual Media Quality Index (W-Index) for Higher Institutions of Education
Get PDFThe simplicity and ease of access of its website, has allowed YouTube to be embraced by the whole world and establish itself as the most prominent form of video sharing on earth. YouTube has become a widely used medium for individuals, corporations, and academic institutions alike. In the current work a W-index has been developed and applied to many academic institutions to evaluate the efficacy of the respective YouTube channel(s). This index was the creative product of the senior author who was inspired by the H-index developed by J.E. Hirsch (2005) to evaluate the productivity and impact of a researcher. The W-index will be used to evaluate the quantity and quality of a University’s channel that is different from the traditional staples that define popularity and video effectiveness on YouTube, such as total views. The methodology used would be to see that if this W-index would correlate well to existing indices used for the evaluation of universities. Eventually, the W-index could serve as an indicator of whether or not a university needs to invest time or money into the development of better videos or more videos for their YouTube channel to maximize its impact on the academic community. A correlation between W-Index and three well-established and well-defined cybermetric rankings; US Rank, Impact Rank, and Excellence Rank, is established and used as the basis for the Windex’s usefulness. The establishment of such a correlation indicates that the W-Index can also be used to evaluate the communication efficacy of individuals, despite the lack of any robust ranking system for individuals. The W-Index serves as a good indicator, based on consistent correlation coefficients among ranking systems analyzed, of a university or individual’s success and communication efficacy. Rankings are useful as single numbers that contribute to decision making, simply because of their simplicity