The Provision Of Polygamy In The Family Law Of Islamic Countries (Saudi Arabia, Turkey, Tunisia, Malaysia And Indonesia)

Secara teoritis, ketentuan poligami telah diatur dalam kitab-kitab fiqh yang sejak lama telah dipedomani oleh seluruh umat Islam di dunia. Seiring dengan perkembangan zaman, praktik poligami ini bagi sebagian negara Islam tidak diperbolehkan karena dianggap tidak sesuai lagi dengan kondisi budaya masyarakatnya. Bagi sebagian negara lain, poligami masih dibolehkan dan mereka memegang teguh prinsip poligami sebagaimana yang  telah diformulasikan para ulama Fikih. Sementara itu, sebagian negara lain  meghendaki adanya pra-syarat yang ketat bila warganya hendak melakukan poligami. Tulisan ini akan mencoba menelisik ketentuan poligami di negara-negara Islam di Dunia meliputi Saudi Arabia, Turki, Tunisia, Malaysia dan Indonesia dan mencoba melakukan analisis perbandingan. Pilihan kelima negara ini sejatinya karena akan menggambarkan polarisasi kedalam tiga bentuk penerimaan negara Islam terhadap ketentuan poligami

Experimental analysis of vacuum pressure and gas flow rate in structured-core transparent vacuum insulation panels

The notion that modern buildings should strive to be net-zero energy buildings (NZEBs) is widely accepted. One of the causes leading to high energy usage for space heating, resulting in avoidable carbon emissions, is heat loss via building windows. In order to improve window’s insulation in existing buildings, structured-core transparent vacuum insulation panels (TVIPs) are proposed. TVIPs mainly consist of the structured core material, the low-emissivity film, and the transparent gas barrier envelope. TVIPs have high insulation performance and are inexpensive to manufacture and can be easily installed. Therefore, TVIPs have the potential to improve window’s insulation in existing buildings at a low cost. However, it is necessary to overcome the issue of preventing the pressure rise inside TVIP after vacuum sealing. The authors constructed an experimental setup to quantify the effect of reduction of gas flow rate in TVIP after evacuation by applying the pressure-rate-of-rise-method. In this experiment, a gas barrier film with a straw was used as the vacuum chamber. This could reproduce the pressure increase in the TVIP after sealing and the gas flow rate in the TVIP is evaluated. The experimental result shows that the coated core material and the enclosing getter agent lowered the pressure rise and gas flow rate in TVIP by combining concurrent evacuation and heating. Furthermore, after extending the simultaneous vacuuming and heating period to 8 h and applying the coated core material, and enclosing the getter agent, the internal pressure in TVIP may be lowered to around 1 Pa after 30 min after halting vacuuming. It was confirmed that this pressure satisfied the performance required for TVIPs, and the result was much closer to the realization of TVIPs

Thermal performance analysis of a new structured-core translucent vacuuminsulation panel in comparison to vacuum glazing: Experimental and theoretically validated analyses

The notion at which, nowadays, building sector is being recognized to be nearly zero-energy buildings (NZEBs) relies partly on the thermal performance of its fabric insulation. Vacuum glazing (VG) technology attracted the research interest as an option to reduce heat loss through windows. However, the total glazing thermal transmittance (U-value) for VG increases with the use of smaller glazing area due to the edge-seal effects, due to the thermal short-circuit around the edges and the overall construction cost of VG leading to an unaffordable option to deal with energy conservation of buildings. Therefore, this study aims to propose a new structured core transparent vacuum insulation panel (TVIP) to accomplish insulation for the windows without edge sealing effect, with lower cost and can be easily retrofitted to the conventional windows of the existing buildings. To do this, VG and TVIP were constructed and their thermal conductivity were measured using heat flow meter apparatus. In addition, a 3D finite volume model considering the effect of surface to surface radiation, gas conduction, and thermal bridges through the spacer material and sealing material is developed. The model is validated with the experiments in this work and with the data for VG in the literature. The effect of vacuum pressure increase is simulated to mimic the vacuum deterioration problem and the effect of glazing size on the insulation performance of both VG and TVIP were investigated. The results indicate that for a smaller glazing area of less than 30 cm × 30 cm, the TVIP accomplished lower U-value compared with the VG at vacuum pressure of 0.1 Pa and 1 Pa. While, at a vacuum pressure of 10 Pa, the TVIP attained a lower U-value over the entire range of the investigated glazing sizes. Further, the edge-seal effect in the VG is diminished with the use of TVIP. Furthermore, the material cost per unit area of the TVIP is three times less than the cost of VG at laboratory scale. The results of the current study can guide vacuum window designers and researchers to further enhance the performance of TVIP based window to compete for the VG in the markets

Cultural Dimensions’ Effects on Perceptions of Learning Using Social Media: A Comparative Study between the University of Sharjah and the University of Arkansas Students

This research examines the impact of cultural dimensions on perceptions of social media as an educational tool in two different contexts. The study included 815 students volunteered to answer the survey questions from the University of Sharjah (UoS) in the United Arab Emirates and the University of Arkansas (UoA) in the United States of America. The results were analyzed via SPSS, and then counteracted with a Push-pull-mooring model to check for differences in terms of cultural contexts that would be reflected in perceptions of the value of social media in learning. The results reveal a number of differences. Students from the University of Sharjah are more immersed in social media for learning, and more interested in forming strong, long-term, and reliable collaborative friendships based on the exchange of ideas and academic assistance. By contrast, students from the University of Arkansas seem to be short-term oriented because their use of social media is related to discussion and instant chat. The authors conclude that UoS students’ perceptions reflect a culture of collectivism that invests in social networks to enhance the already deeply rooted offline social activities, while those from UoA reveal a culture of individualism in which social media use is restricted to self-information

Thermal Analysis of a New Sliding Smart Window Integrated with Vacuum Insulation, Photovoltaic, and Phase Change Material

A zero-energy building (ZEB) requires an innovative integration of technologies, in which windows play a paramount role in energy reduction, storage, and generation. This study contributes to four innovative designs of sliding smart windows. It integrates air-gap (AG), phase change material (PCM), photovoltaic (PV), and vacuum glazing (VG) technologies. These smart sliding windows are proposed to generate electricity along with achieving efficient thermal insulations and heat storage simultaneously. A two-dimensional multiphysics thermal model that couples the PCM melting and solidification model, PV model, natural convection in the cavity, and the surface-to-surface radiation model in the vacuum gap are developed for the first time. The model is validated with data in the literature. The transient simulations were carried out to investigate the thermo-electrical performance of a window with an area of 1 m by 1 m for the meteorological conditions of Kuwait city on the 10th of June 2018, where the window was oriented to south direction. The results showed that the total solar heat energy gain per unit window area is 2.6 kWh, 0.02 kWh, 0.22 kWh, 1.48 kWh, and 0.2 kWh for the double AG, AG + PV + PCM + VG, PV + PCM + VG, AG + PV + PCM, and the ventilated AG + PV + PCM + VG, respectively. The results elucidate the advantages of the integration of VG in this integrated sliding smart window. The daily generated PV electrical energy in these systems is around 1.3 kWh, 1.43 kWh, and 1.38 kWh for the base case with double AG, PV + PCM + VG, and the ventilated AG + PV + PCM + VG respectively per unit window area

Analysis of a vacuum-based photovoltaic thermal collector

In this study, a new design of photovoltaic thermal (PV/T) collector is proposed. This design uses a vacuum layer above the silicon wafer and not exists in the traditional PV/T collector. This layer is used to decrease the heat loss from the top surface of the PV/T collector. The analysis is conducted using a 3D thermal modeling. The new collector design with the vacuum layer achieved a 26.6% increase in the thermal power while keeping the electrical the same at Reynolds number of 50 and solar radiation of 1000 W/m2. In addition, the degradation of the vacuum pressure slightly influence the thermal performance while increasing the vacuum pressure from 0.01 Pa to 10 Pa. While further increase in the vacuum pressure from 10 Pa to 1.013×105 Pa substantially decreases the gained thermal power with insignificant increase in the electrical power

Daylighting, artificial electric lighting, solar heat gain, and space-heating energy performance analyses of electrochromic argon gas-filled smart windows retrofitted to the building

The inevitability to reduce CO2 emissions to avoid preventable climate change is widely being yelped. To minimise the impact of rapidly changing climate, this paper presents novel research findings and contributes to developing electrochromic argon gas-filled glazed smart windows retrofitted to the building with IoT based transparency control. In this, the comparative analyses of the daylighting, electrical lighting, solar heat gain, and space-heating load of the building using the dynamic thermal and electric lighting modelling methods based on real weather temperatures are presented. The daylighting analysis results implicate that the building with electrochromic argon gas-filled smart windows reduced 19% of daylight illuminance during summer months compared with the building retrofitted with double air-filled glazed windows daylight factor remains consistent. As such, the solar heat gains analysis results implicate at least 50 % annual solar heat gain reduction predicted in the building with electrochromic argon gas-filled smart windows in comparison to double air-filled windows. This leads to the conclusion of the space-heating energy analysis that implicates the highest contribution to the space heating demand is the solar heat gain caused by double air-filled glazed windows. The results confirm that the LED artificial electric lighting system requires fewer fittings and thus total power load compared to the fluorescent lighting system, throughout the year, to the building with electrochromic argon gas-filled glazed smart windows. The daylight controls are linked to the electrochromic argon gas-filled glazed smart windows, so they only operate when the glazing is tinted, or the daylight level drops below a set level; this will reduce the energy usage and also lower the space heating of the room

Experimental and theoretical performance evaluation of parabolic trough mirror as solar thermal concentrator to thermoelectric generators

This paper presents the prospects of harnessing radiative heat from the sun with a parabolic trough mirror, as a solar thermal concentrator, in comparison to the mathematical model and experimental quartz-halogen concentrator model for the electrical energy conversion utilizing thermoelectric generators (TEG). The construction and design of TEG-setup along with Parabolic trough mirrors and quartz-halogen lamps are presented. The Parabolic trough mirror used as a focal point at a distance of 19.05 cm. With eight quartz-halogen concentrated heat, the maximum performance achieved at ΔT of 11.8 K, Voc of 292 mV and Isc of 95.8 mA, recorded at the concentrated hot-side surface temperature of 317.8 K. When compared to the natural solar concentrated heat, higher temperature of 473.15 K at the hot-side surface temperature of TG was achieved. It is concluded that the heat concentration of the parabolic mirror increases with an increase in the intensity of heat using natural solar radiations. The Voc of 1.76 V and Isc of 1.1 A at a temperature difference of 110 K were measured, which are in good agreement with validated mathematical results. The parabolic through mirror utilized is smaller in size and thus collected lesser sun rays than the larger dish style mirror, and hence the heat in the focal point was very low, for better results, parabolic trough mirror with higher surface area would be important for future experiments