Solar Architecture Integrated Bi-Facial Photovoltaic System as a Shade

Solar architecture is defined as a kind of building integrated photovoltaic (BIPV) in which the PV modules are deployed to passive solar concepts, to minimize the heating and cooling load, to upgrade the indoor environment, and to be adjustable for regional weather and to continuously succeed architectural culture. Solar architecture needs to consider the architectural culture and climate of the region through an ecological convergence. The ecological criteria lead to optimizing solar architecture through an ecological convergence of a passive intelligence and renewable energy system. The optimal angle of the bi-facial PV module as a shade is 23.5° considering the physical interaction and the traditional architecture in Korea according to the ecological criteria. The shading concept of the PV module reduces 27.5~34% of the building cooling load. Effective solar irradiance (ESR) is very important not only for PV efficiency but also for the system usage rate. This ESR should be controlled depending on the climate condition to maximize the total energy elimination factor and total energy transmittance factor for a window. The MB-BIPVS play an excellent role to maximize the total energy elimination factor and total energy transmittance factor for a window.

RADIOLOGICAL EVALUATION OF LEAD APRON INTEGRITY IN FIVE SELECTED HOSPITALS IN ABUJA, NIGERIA

Background: The general consensus is that any exposure to ionising radiation carries a risk. Diagnostic radiology is the largest (87%) contributor to man-made ionising radiation, therefore any economical and socially acceptable means of reducing dose without compromising the diagnostic value of the procedure must be worth implementing. Aim: This study is aimed at evaluating lead apron integrity in five selected Hospitals in Abuja, Nigeria. Methodology: The methodology approach includes the application of a large area beam for transmission measurement with the placement of OSLD before and behind the ten (10) lead aprons to determine the entrance and exit dose as well as the transmission factor. In this study, a lead apron consisting of 0.25mm and 0.35mm thickness were examined. Results: The result shows that the transmittance factor of the entrance and exit dose through the lead equivalent aprons is directly proportional to the age of the apron with NHA1 having the highest transmission factor (0.83) and oldest age (16 years). WGH2 has the lowest transfer factor (0.12) and the least age (1 year). Conclusion: Lead aprons loses their attenuation capability over time and should be replaced after 15 years at most for effective protection against ionizing radiation.

Cloud effects on surface radiation balance at Helheim and Jakobshavn Glaciers (Greenland) using ground-based observations

<p>The surface radiation budget is an essential component of the total energy exchange between the atmosphere and the Earth’s surface. Measurements of radiative fluxes near/on ice surfaces are sparse in the polar regions, including on the Greenland Ice Sheet (GrIS), and the effects of cloud on radiative fluxes are still poorly studied. In this work, we assess the impacts of cloud on radiative fluxes using two metrics: the longwave-equivalent cloudiness, derived from long-wave radiation measurements, and the cloud transmittance factor, obtained from short-wave radiation. The metrics are applied to radiation data from two automatic weather stations located over the bare ground near the ice front of Helheim (HG) and Jakobshavn Isbræ (JI) on the GrIS. Comparisons of meteorological parameters, surface radiation fluxes, and cloud metrics show significant differences between the two sites. The cloud transmittance factor is higher at HG than at JI, and the incoming short-wave radiation in the summer at HG is 50.0 W m−2 larger than at JI. Cloud metrics derived at the two sites reveal   a high dependency on the wind direction. The total cloud radiative effect (CREnet) generally increases during melt season at the two stations due to long-wave CRE enhancement by cloud fraction.  CREnet decreases from May to June and increases afterward, due to the strengthened short-wave CRE. The annually averaged CREnet were 3.0 ± 7.4 W m-2 and 1.9 ± 15.1 W m−2 at JI and HG.  CREnet estimated from AWS indicates that clouds cool the JI and HG during melt season at different rates.</p>

Meteorological Conditions and Cloud Effects on Surface Radiation Balance Near Helheim Glacier and Jakobshavn Isbræ (Greenland) Using Ground-Based Observations

The surface radiation budget is an essential component of the total energy exchange between the atmosphere and the Earth’s surface. Measurements of radiative fluxes near/on ice surfaces are sparse in the polar regions, including on the Greenland Ice Sheet (GrIS), and the effects of cloud on radiative fluxes are still poorly studied. In this work, we assess the impacts of cloud on radiative fluxes using two metrics: the longwave-equivalent cloudiness, derived from long-wave radiation measurements, and the cloud transmittance factor, obtained from short-wave radiation data. The metrics are applied to radiation data from two automatic weather stations located over the bare ground near the ice front of Helheim (HG, 66.3290°N, 38.1460°W) and Jakobshavn Isbræ(JI, 69.2220°N, 49.8150°W) on the GrIS. Comparisons of meteorological parameters, surface radiation fluxes, and cloud metrics show significant differences between the two sites. The cloud transmittance factor is higher at HG than at JI, and the incoming short-wave radiation in the summer at HG is about 50.0 W m−2 larger than at JI. Cloud metrics derived at the two sites reveal partly cloudy conditions were frequent (42 and 65% of the period at HG and JI) with a high dependency on the wind direction. The total cloud radiative effect (CREnet) generally increases during melt season at the two stations due to long-wave CRE enhancement by cloud fraction. CREnet decreases from May to June and increases afterward, due to the strengthened short-wave CRE. The annually averaged CREnet were 3.0 ± 7.4 W m−2 and 1.9±15.1 W m−2 at JI and HG. CREnet estimated from AWS indicates that clouds cool the JI and HG during melt season at different rates.

Numerical Pathology in Selected Kubelka–Munk Formulas, and Strategies for Mitigation

Causes of numerical pathology in formulas for reflectance factor (R), transmittance factor (T ), and reflectance factor over a perfectly black background (R 0 ) under the Kubelka–Munk model are posited, and alternate formulas believed less prone to these pathologies are introduced. Suggestions are offered not only for R, T , and R 0 , but also for intermediate or adjunct quantities used in the main formulas. Computational experiments were performed to verify that the new models produce the same results as the existing ones under non-pathological conditions, exhibit acceptable levels of precision in a customary floating-point environment, and are more robust with respect to edge cases where an input quantity is zero. The new formulas performed well, with some evidence that the new hyperbolic forms provide better accuracy than their exponential counterparts.

Экспериментальное исследование перестраиваемого акустического фазовращателя

The paper presents the results of a numerical and experimental study of an acoustic phase-shifter based on a chain of rectangular Helmholtz resonators. Phase regulation of the transmitted acoustic wave is made by simultaneously changing the resonators volumes with the stepper motor. As a result of the experiment it was found that the developed acoustic phase-shifter allows to manipulate the wave phase within the range of 0 - 2π in the frequency range of 2000 - 2500 Hz. The transmittance factor is not less than 0.7. The phase-shifter can be used as a unit cell of tunable acoustic metasurface.

Comparative Analysis Based on the Spike Glycoproteins of SARS-CoV2 Isolated from COVID 19 Patients of Different Countries

SARS-CoV2 popularly known as (COVID-19) has presently received worldwide attention. It has been considered a pandemic by the World Health Organisation. Owing to its high transmittance factor the virus has brought about many deaths and spread to all the major countries of the world. Scientists and Researchers worldwide are giving their full efforts to develop a vaccine. In our present study, we have included the comparative analysis of the different spike glycoprotein sequences of the patients suffering from COVID-19 from different countries where this pandemic has occurred. Spike glycoproteins are the structural proteins that bring about the binding of the SARS-CoV-2 viral molecule to the ACE2 receptor of the host following which infection occurs. Through this data, we have shown the different point mutations in the spike glycoproteins that occurred over time in different countries as the disease progressed.

Analysis of Thermal Energy Distribution from Low Yield Nuclear Explosions

This study is dedicated for the determination of the distribution of thermal energy resulted from different types of a 50-70 KT yield nuclear explosion; surface, aerial, in different locations away from the explosion center and considering the differences in the transmittance factor and visibility conditions that may affect the distribution of thermal energy. The results showed that the majority of released thermal energy occurs during a very short period of time after explosion, and reaches its maximum of 22 KT after about 3.1 sec. Also, it was determined the absence of significant effect for the visibility degree on the value of the total thermal exposure for both types of explosions, and that the thermal exposure due to the surface explosion is about 60% of its value in case of the aerial explosion.

Estimation of Global Solar Radiation using Pyranometer and NILU-UV Irradiance Meter at Pokhara Valley in Nepal

The global solar radiation (GSR) and cloud transmittance factor (cf) are measured at the horizontal surface since 2009 using calibrated CMP6 Pyranometer and NILUUV Irradiance Meter at Pokhara (28.22°N, 83.32°E) which is about 800m from the sea level lying just 20km south of the Himalayas. This paper explains the daily, monthly and seasonal variation of global solar radiation and also compared with temperature and rainfall to global solar radiation. The annual average daily global solar radiation is about 4.81 kWh/m2/day which is sufficient to promote solar active and passive solar energy technology at sub-Himalaya terrain Pokhara and other similar geographical locations. The correlation coefficient 0.70 is found in between clearness index (K) and cloud transmittance factor (cf). This novel result can be used for location of similar meteorological and geographical characteristics at which solar data are not available. DOI: http://dx.doi.org/10.3126/jie.v9i1.10672Journal of the Institute of Engineering, Vol. 9, No. 1, pp. 69–78