The Way of the Increasing Two Times the Efficiency of Silicon Solar Cell

Increase of the efficiency of the solar cells which are produced in industry, is important. Increase of efficiency of solar cells was identified, when nanoplasmonics phenomenon was formed in solar cell. So, in this article, influence of nanoparticles Pt, Au, Ag and Cu on properties of silicon based solar cell has been studied. When nanoparticle Pt was inclused in silicon based solar cell, its efficiency increased 2.31 times. Optimal radius of nanoparticule Pt was identified to be between 15-25 nm.

Optimization of the Plastic Area of a Borehole Based on the Gas Extraction Effect and Its Engineering Application

Gas extraction is most commonly used to control gas disasters in coal mines. The distribution of the plastic zone around a borehole and the sealing quality are key factors affecting gas extraction. In this paper, the plastic zone was simulated by COMSOL, and a theoretical equation of the plastic zone radius was derived. In addition, an antispray hole equipment and the “two plugging and one injection” sealing technology were proposed. The results show that a larger borehole pore size corresponds to a larger plastic zone and larger range of pressure relief of the borehole. The error between the calculated and simulated plastic zone radii is within 1%, and the modified equation is applicable to Puxi mine. The loss and harm caused by borehole spraying are reduced by applying antispray hole equipment. By applying the “two plugging and one injection” sealing technology and phosphogypsum-based self-produced gas expansion paste material to block the borehole, the sealing quality is improved and an accurate gas mixing flow, pure flow, and concentration were obtained. As the plastic zone enlarges, the gas extraction flow gradually increases with, but the relative variation of flow first increases and subsequently decreases. Considering the safety and economy of construction, the optimal radius of the plastic zone is 64.9 mm.

SELECTION OF THE EXTERNAL WALL ROUNDING ANGLE OPTIMAL RADIUS

The article analyzes one of the ways to increase the heat-protective properties of thebuilding corner - rounding the outer surface of the outer wall the corner . The walls of houses nearthe outer corner, due to their configuration, have less heat-insulating properties than the walls inother areas. This is due to the fact that the area of heat flow perception on the inner surface of thewalls at an angle less than the area of heat transfer on the outer surface. Convective heat exchangenear the inner surface of the corner, due to the inhibition of air movement is less than in other areas,so the amount of heat coming from the indoor air to the wall surface is less. For climatic conditionsof Poltava region the research of temperature fields of calculated sections of the wall (withoutrounding of a corner, with rounding of a wall of various radius an external surface) with definitionof a heat stream size, the minimum temperature on an internal surface of a wall and the resulted heattransfer resistance is carried out. The dependences of the rounding radius of the wall outer surfaceon the heat flow passing through the design area of the wall outer corner, brick consumption withinthe design area, insulation consumption within the design area, the amount of room area reductiondue to rounding the wall for five design schemes. The analysis of dependences the constructed graphsshowed that the intensive reduction of the heat flux passing through the calculated section occurs ata radius of the wall outer surface rounding of 0.9 m and more; a slight decrease in the area of theroom due to the rounding of the wall occurs to a radius of curvature of 1.4 m; intensive reduction ofbrick volume within the calculated area occurs when the radius of curvature is more than 0.8 m,similarly to mineral wool up to 0.7 m. It is determined that the optimal radius of curvature of theouter wall is 0.8 m, it will increase the thermal properties of the angle and reduce the heat transfercoefficient by the transmission of the external enclosing structure of the building as a whole.

Spontaneous Imbibition in a Fractal Network Model with Different Wettabilities

In this work, we derived a mathematical model for spontaneous imbibition in a Y-shaped branching network model. The classic Lucas–Washburn equation was used for modeling the imbibition process occurring in the Y-shape model. Then, a mathematical model for the Newtonian fluid’s imbibition was derived to reveal the relationship between dimensionless imbibition time and length ratio, radius ratio, and wetting strength. The dimensionless imbibition time in the model was adopted to compare with that of the capillary bundle model. Different length and radius ratios were considered in the adjacent two-stage channels, and different wettabilities were considered in the different branches. The optimal radius ratio, length ratio, and wetting strength were calculated under the condition of the shortest imbibition time. In addition, the shortest dimensionless imbibition time of the three-stage Y-shaped branching network model was calculated when the wettability changes randomly. The results indicate that the imbibition time changed mostly when the wettability of the second branch changed, and the second branch was the most sensitive to wettability in the model.

Redesign of the Geometry of Parts Produced from PBT Composite to Improve Their Operational Behavior

Parts produced from PBT-GF30 (70% polybutylene terephthalate +30% fiberglass) are very often used in car construction, due to the properties of this material. The current trend is to make parts with a shape designed to be as complex as possible, to take over many functions in operation. During the research, a part that is a component of the structure of car safety systems, and that must be completely reliable in operation, was analyzed. This piece has a complex shape that involves the intersection of several walls. Thus, the research aimed at establishing the optimal radius of connection between the walls (R), the ratio between the thickness of the intersecting walls (K) and the angle of inclination of the walls (α). The composite central design method was used to design the experiments. Both new parts and parts subject to an artificial aging process were tested. All parts were subjected to shear stress, to determine the load (L) and displacement (D) at which they break. In order to observe other changes in the properties of the parts, in addition to the mechanical ones, an analysis of the color of the new and aged parts was performed, as well as a topography of the surface layer in the breaking area. The design of the parts involved changes to the parameters of the injection process. In these conditions, a PBT-GF30 viscosity analysis was performed for new and artificially aged parts.

Mapping The Capacity of The Mosque in Spatial Review in East Bogor Sub-District

<p><em>The increasing awareness of Muslims about Islam encourages them to participate in activities carried out by mosque administrators, this has an impact on the capacity of the mosque space. This study aims to determine the distribution of mosques and their capacities based on the population in East Bogor Sub-District. Data collection is done by using spatial data to support decision making to increase efficiency and time accuracy by using the buffering method. Where the buffer is to determine the optimal radius assuming distances of 100 m, 250 m, 500 m, and 1000 m. The results showed that in East Bogor District there were 73 mosques and the capacity of the mosques was 33.72% of the total population of 106,029 people.</em></p>

Distance from the outbreak of infection, ozone pollution and public health consequences of SARS-CoV-2 epidemic

Background Italy was the second country in the world, after China, to be hit by SARS-CoV-2 pandemic. The Italy’s experience teaches that steps to limit people’s movement by imposing “red zones” need to be put in place early by carefully identifying the cities to be included within these areas of quarantine. The assessment of the relationship between the distance from an established outbreak of SARS-CoV-2 infection with transmission-linked cases and mortality observed in other sites could provide useful information to identify the optimal radius of red zones. Methods We investigated the relationship between SARS-CoV-2 cases and the distance of each Italian province from the first outbreak of SARS-CoV-2 epidemic in Italy (the city of Lodi placed in the Lombardia region). In 38 provinces of Lombardia and neighboring regions, we performed a breakpoint analysis to identify the radius of the red zone around Lodi minimizing epidemic spread and mortality in neighboring cities. Results In all Italian provinces a non-linear relationship was found between SARS-CoV-2 cases and distance from Lodi. In an analysis including the provinces of Lombardia and neighboring regions, SARS-CoV-2 cases and mortality increased when the distance from Lodi reduced below 92 km and 140 km, respectively, and such relationships were amplified by ozone (O3) pollution. Conclusions The breakpoint analysis identifies the radius around the outbreak of Lodi minimizing the public health consequences of SARS-CoV-2 in neighboring cities. Such an approach can be useful to identify the red zones in future epidemics due to highly infective pathogens similar to SARS-CoV-2.

An isoperimetric problem with a Coulombic repulsion and attractive term

We study an energy given by the sum of the perimeter of a set, a Coulomb repulsion term of the set with itself and an attraction term of the set to a point charge. We prove that there exists an optimal radius r0 such that if r < r0 the ball Br is a local minimizer with respect to any other set with same measure. The global minimality of balls is also addressed.