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Laser additive manufacturing of Zn-2Al part for bone repair: Formability, microstructure and properties
摘要： Zinc (Zn) alloys are promising bone repair materials due to their inherent degradability, favorable mechanical property and biocompatibility. In this investigation, laser powder bed fusion (LPBF) known as a representative additive manufacturing technique was applied to fabricate Zn-2Al (wt.%) part for bone repair application. A low energy density (Ev) led to the formation of pores and resultant insufficient densification rate due to the high liquid viscosity within the molten pool. In contrast, a high Ev caused the evaporation of Zn powder and resultant failure of LPBF. With Ev increasing, the obtained grains and the precipitated lamellar eutectic structure contained η-Zn and α-Al phase became coarsened, which could be attributed to the enhanced heat accumulation and consequently decreased cooling rate. At optimized Ev of 114.28 J/mm3, fully dense Zn-2Al part with a densification rate of 98.3±1.4% was achieved, which exhibited an optimal hardness of 64.5±1.8 Hv, tensile strength of 192.2±5.4 MPa and a moderate corrosion rate of 0.14 mm/year. In addition, in vitro cell tests confirmed its good biocompability. This study indicated that LPBF processed Zn-2Al part was a potential material for bone repair.
关键词： Zn alloys,laser additive manufacturing,mechanical properties,degradation rate,biocompability
更新于2025-11-21 11:18:25
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[IEEE 2018 2nd International Conference on Energy Conservation and Efficiency (ICECE) - Lahore, Pakistan (2018.10.16-2018.10.17)] 2018 2nd International Conference on Energy Conservation and Efficiency (ICECE) - Performance Analysis of First Grid Connected PV Power Plant in Subtropical Climate of Pakistan
摘要： With the increasing penetration of both grid connected and standalone photovoltaic (PV) systems in Pakistan to cater the shortfall of energy, it is necessary to determine the performance and durability of already installed PV systems in different climates of country. This work aims to analyze the performance of first grid connected PV power plant located in Islamabad, Pakistan. The performance degradation of PV plants primarily depends on PV modules type (technology and design), regional climatic factors and field operating conditions. In this paper, performance ratio (PR) and degradation rate have been calculated from meteorological and performance data of plant to investigate the energy efficiency and modules quality over the course of operational years. Temperature losses due to module operating temperature were also estimated that primarily contribute to overall energy losses. This evaluation is of paramount importance for estimating the cost effect of the performance, identification of the underlying performance degradation and energy losses mechanisms, that help investors to choose climate specific modules technology and design for future plants and also to make efficient scheduling for preventive maintenance.
关键词： Photovoltaic (PV) system,performance index (PI),energy losses,climatic factors,degradation rate analysis,performance ratio (PR)
更新于2025-09-23 15:22:29
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Operational Performance and Degradation Influenced Life Cycle Environmentala??Economic Metrics of mc-Si, a-Si and HIT Photovoltaic Arrays in Hot Semi-arid Climates
摘要： Life cycle metrics evolution specific to the climate zone of photovoltaic (PV) operation would give detailed insights on the environmental and economic performance. At present, vast literature is available on the PV life cycle metrics where only the output energies ignoring the degradation rate (DR) influence. In this study, the environ-economic analysis of three PV technologies, namely, multi-crystalline silicon (mc-Si), amorphous silicon (a-Si) and hetero-junction with an intrinsic thin layer (HIT) have been carried out in identical environmental conditions. The energy performance parameters and the DR rate of three PV technologies are evaluated based on the monitored real time data from the installation site in hot semi-arid climates. The assessment demonstrates that the HIT PV module technology exhibits more suitable results compared to mc-Si and a-Si PV systems in hot semi-arid climatic conditions of India. Moreover, energy metrices which includes energy payback time (EPBT), energy production factor (EPF) and life cycle conversion efficiency (LCCE) of the HIT technologies are found to be 1.0, 24.93 and 0.15 years, respectively. HIT PV system has higher potential to mitigate the CO2 and carbon credit earned compared to mc-Si and a-Si PV system under hot semi-arid climate. However, the annualized uniform cost (UAC) for mc-Si (3.60 Rs/kWh) and a-Si (3.40 Rs/kWh) are more admissible in relation to the HIT (6.63 Rs/kWh) PV module type. We conclude that the approach of considering DR influenced life cycle metrics over the traditional approach can support to identify suitable locations for specific PV technology.
关键词： annualized uniform cost,amorphous silicon,crystalline solar cells,life cycle assessment,PV cells,energy payback time,life cycle metrics,HIT,photovoltaic systems,degradation rate
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Comparison of TPT and Thermally Conductive Backsheets in One-Cell Modules: Weather and Climate Dependence
摘要： Various improved backsheet materials have been developed and used by the industry to reduce the module operating temperatures. The focus of this paper is to evaluate the thermal characteristics of modules having thermally conductive backsheets (TCB) exposed in three different climatic conditions over two years. In this work, 30 one-cell PV modules with glass/EVA/cell/EVA/backsheet were fabricated using 2 different thermally conductive backsheets (TCB_A and TCB_B) and their backsheet temperatures were compared with conventional tedlar-polyester-tedlar (TPT) under different climatic conditions. The results clearly show that TCB_A operates at lower temperatures compared to TPT under hot climatic conditions with higher ambient temperatures and wind blowing from west direction at speeds 1-2 m/s. On the other hand, TCB_B operates at lower temperature than TPT under temperate climatic conditions with ambient temperatures between 25 and 35 °C and wind blowing from east direction at speeds 2-3 m/s.
关键词： weather dependence,degradation rate,thermally conductive backsheet,module operating temperature,TPT
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE PES Innovative Smart Grid Technologies Conference - Latin America (ISGT Latin America) - Gramado, Brazil (2019.9.15-2019.9.18)] 2019 IEEE PES Innovative Smart Grid Technologies Conference - Latin America (ISGT Latin America) - Performance and Durability Analysis of Photovoltaic Panels under Different Climatic Conditions
摘要： Analysis of the performance and durability of photovoltaic (PV) panels allows a coherent and assertive planning. In this study the main causes of PV panel's degradation are evaluated, thus presenting a way to obtain its degradation rate (DeR). The DeR was applied to a simulation in the program OpenDSS to verify electrical losses along panel’s lifetime. Simulations in different scenarios were run to evaluate the degradation levels in different locations. With these results was possible to predict the durability of some PV modules and to validate them with a reasonable precision degree. The conclusion is that in hot climates with high degradation rates, the PV generation may remain higher along the guarantee period than in locations where degradation rates are lower. Thus, this study provides a substantial assertiveness for investments in PV generation.
关键词： PV panel performance,Lifetime,Photovoltaic generation,Degradation rate
更新于2025-09-16 10:30:52
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Reducing Interanalyst Variability in Photovoltaic Degradation Rate Assessments
摘要： The economic return on investment of a commercial photovoltaic system depends greatly on its performance over the long term and, hence, its degradation rate. Many methods have been proposed for assessing system degradation rates from outdoor performance data. However, comparing reported values from one analyst and research group to another requires a common baseline of performance; consistency between methods and analysts can be a challenge. An interlaboratory study was conducted involving different volunteer analysts reporting on the same photovoltaic performance data using different methodologies. Initial variability of the reported degradation rates was so high that analysts could not come to a consensus whether a system degraded or not. More consistent values are received when written guidance is provided to each analyst. Further improvements in analyst variance was accomplished by using the free open-source software RdTools, allowing a reduction in variance between analysts by more than two orders of magnitude over the ?rst round, where multiple analysis methods are allowed. This article highlights many pitfalls in conducting “routine” degradation analysis, and it addresses some of the factors that must be considered when comparing degradation results reported by different analysts or methods.
关键词： photovoltaics,RdTools,Degradation rate,round-robin
更新于2025-09-12 10:27:22
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Investigation of Operating Parameters and Degradation of Photovoltaic Panels in a Photovoltaic Power Plant
摘要： Recently, the use of photovoltaic (PV) cells and the increase in the number of photovoltaic power plants has led to a detailed examination of their operating parameters. In this article, we discuss material and operating parameter influences on the performance and efficiency of photovoltaic panels in a photovoltaic power plant. The plant consisted of 3600 pieces of polycrystalline PV panels from Renewable Energy Corporation (REC) Solar (type REC 230AE) with a maximum power of 230 Wp. Parameter measurements were made three years after the power plant was started. The measured and computed data were statistically processed using multidimensional statistical methods where the relationships between input and output variables were examined, which was subsequently quantified by regression analysis. Using the ANOVA, the variability of the measured efficiency of the panels and the performance for individual years was examined. Efficiency has been found to increase significantly over the years. The reason for this is the statistically proven prevailing operating time of the PV power plant in conditions with lower temperature than standard operating conditions (25 °C). Ageing was not confirmed in optimal conditions and calculated efficiency was constant.
关键词： photovoltaics panel,photovoltaic power plant,efficiency,operational parameters,degradation rate
更新于2025-09-12 10:27:22
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Performance evaluation and degradation assessment of crystalline silicon based photovoltaic rooftop technologies under outdoor conditions
摘要： Keeping track of ?eld performance and degradation rate of photovoltaic panels in regions with diverse environmental exposures is critical. The objective of this paper is to determine two and half year performance characteristics and degradation rate of poly-crystalline and heterojunction with intrinsic thin layer roof-top photovoltaic units under prevailing weather conditions in the Central Anatolia region. Degradation rates of the photovoltaic units were determined through analysing the effective peak power, and the temperature corrected performance ratio of each technology. Processing of the measured data covering the test period reveals that the thin ?lm technology offers lower degradation rate with nearly (cid:1)0.1% than the poly-crystalline based technology within the range of (cid:1)0.67% to (cid:1)0.83%, respectively. The study allows a better understanding of variations in performance and behaviour of the output power of poly-crystalline and heterojunction with intrinsic thin layer roof-top photovoltaic units after 2.5 years of outdoor exposure.
关键词： Degradation rate,Performance,Outdoor test,PV
更新于2025-09-11 14:15:04