Finite element modeling of Charpy impact test was performed for a normalized carbon
steel specimen based on plane strain geometry and bilinear isotropic hardening plasticity. As the
suggested approach takes into account all aspects of nonlinearity such as geometric, material and
contact nonlinearities, it may describe the conventional destructive impact test accurately with
much less effort and cost. A failure criterion is assumed to be at 10 % of plastic strain based on the
tensile experiment data. Impact energy was estimated at different testing temperatures. It was
found that impact energy required for fracture of the selected steel specimen at room temperature
(i.e. 25 °C) is to be 65.9 Joul. According to simulation results, it is found that the ductile to brittle
transition temperature (DBTT) equals 0 °C. In order to validate the numerical model, a comparison
study was established by comparing the numerical results with the corresponding experimental tests
at the same conditions, which shows good match with maximum deviation of 5 % for all computer
runs.
During the recent decades, the world has seen ongoing economic and technological development which resulted in the generation of huge volumes of electrical and electronic waste (e-waste). In the Middle East, the United Arab Emirates (UAE) ranks among countries with large e-waste generation due to its consumers’ high spending on electronic devices thereby resulting in a high obsolescence rate in the country. Accordingly, this study aims to analyze the e-waste management and recycling practices in the UAE. It takes Dubai as a case study and conducts a structured questionnaire to analyze households’ awareness, consumption of electronic devices in general and mobile phones in particular, and the disposal behavior of e-waste. Waste mobile phones is taken as a key representative in this study, in which potential waste mobile phones is estimated using the Approximation 1 method in the period 2021–2030. Results from the survey illustrated gaps among households’ awareness and disposal behavior of e-waste, where e-waste recycling rates were noticed to be low. Based on these gaps, strategies were proposed for an effective e-waste management system in the context of Dubai, and were supported by the proposal of an e-waste legislation framework in the UAE.
This paper addresses the thermal performance of integrating Earth Air Heat Exchanger (EAHE) systems with the conventional air conditioning systems in residential buildings in UAE. The proposed system was designed and simulated using a transient analysis tool TRNSYS. The system components were optimized by evaluating the effect of varying several design parameters on the performance of the system. It was found that the optimized design of the earth tubes could potentially reduce the temperature of the ambient air from 46 °C to around 29 °C, when the earth tubes were buried at 4 meters depth below the ground surface. This pre-cooled fresh (atmospheric) air from earth tubes was then mixed with the return air in the mixing chamber of conventional air cooling systems before supply to the building. In order to assess the system feasibility, the proposed system was modelled and implemented on a realistic case study represented by a four-floor residential building located in Dubai. This building comprised a total roof area of 400 m2 and an annual cooling load requirement of 366 kW. The results showed good potential of savings in terms of lowering the Annual Energy Consumption (AEC) and the consequent reduction in CO2 emissions.
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