The bows and rings of dawn and dusk

The arcs of dawn and dusk are natural phenomena that define the boundary of the border between day and night. They are associated with the refraction of solar rays at high angles of incidence that converge to project an arc of light onto the back side of the earth's atmosphere. The rings of dawn and dusk, in turn, are associated with rays, also at large angles of incidence, which converge to project the image of the Sun. Arcs and rings become visible by scattering light by clouds or particles suspended in atmospheric air in the region in which they occur. Here we show a model that describes these natural phenomena and report the first-time record image produced in July of this year.

Degradation of Diclofenac under Irradiation of UV Lamp and Solar Light Using ZnO Photo Catalyst

Diclofenac sodium (DCF) is a non-steroidal anti-inflammatory drug mainly used as an analgesic, arthritic and anti-rheumatic. This study deals with the degradation of diclofenac by photo catalytic-based advanced oxidation processes. Artificial UV lamp and solar rays have been applied to activate the ZnO catalyst, thereby generating highly oxidizing species. These species initiate the degradation process of the drug, which results in intermediates that finally dissociate into carbon dioxide and water. The solar reactor system is comprised of quartz and borosilicate tubes alternatively for the absorption and transmission of the solar rays to the pollutant sample. The degradation rate has been analyzed by composition analysis using high performance liquid chromatography. TOC and COD tests have also been conducted for degraded samples. ZnO catalyst loading was tested from 0.1 gm/L to 1 gm/L and the degradation rate showed a rising trend up to 0.250 gm/L, but further increase in loading resulted in a drop in degradation. Similarly, degradation is higher in acidic condition as compared to neutral or basic pH. The results showed a higher degradation rate for UV lamp irradiation as compared to the solar system. Moreover, TOC and COD reduction is also found to be higher for UV lamp photo catalysis.

Solar Cookers and Dryers: Environmental Sustainability and Nutraceutical Content in Food Processing

This work reviewed the state of the art concerning solar cookers and dryers used in food processing. The general description of solar cookers and dryers was presented, with a specific attention to the equipment where the cooking takes place with the contribution of the direct sunlight. Some insight about the history of design and development of devices that use solar light to process food were provided. The possibility to store the heat produced by solar light using Phase Change Materials was analyzed. Moreover, some “case-studies” were revised and discussed, in which solar light is efficiently used to dry or cook food, focusing on the quality of the food in terms of nutraceuticals content. The analyzed literature points out the necessity for further research about the effects produced by direct solar rays on different foods. The reliable data on this aspect will allow assessment of the quality of food transformation by solar cookers and dryers, adding a strong incentive to the development of such devices, up to now primarily motivated by energy-saving and environmental issues.

Analysis of A Two-Axis Solar Tracker System: Case Study

The environmental pollution that arose from the 20th century has led to the search for clean and renewable energies, so this research aims to determine the efficiency of a two-axis solar tracker system, through the analysis of the data obtained. In view of the fact that it remains perpendicular to the solar rays for a longer time, which automatically moves to the point where the radiation source is. Mathematical models were considered for this study based on parameters of time, voltage, solar radiation, temperature, ultraviolet radiation, inclination angles, and cardinal points, to which the panel was directed during the test days. The efficiency given by the solar panel was obtained as 15.34% on average among monocrystalline silicon solar panels. It was concluded with the analysis of the most relevant data that are, the voltage, the solar radiation, and the angle of inclination to determine with these three parameters if the dual-axis tracker system had an excellent capture of solar radiation in the test days, in order to make the collection and production of solar energy more efficient.

A ROADMAP TO UV-PROTECTIVE NATURAL RESOURCES: CLASSIFICATION, CHARACTERISTICS, AND APPLICATIONS

Alongside the innumerable benefits of solar rays, the adverse effects of ultraviolet (UV) radiation must be considered. All organisms are subjected to the deleterious effects of UV radiation, particularly UVA...

Influence of an aluminium concentrator corrosion on the output characteristic of a photovoltaic system

The climate changes observed over the last decades have been promoting a massive transformation on the energy sector, that is still, in truth highly dependent on fossil fuels. Renewable energies are a plausible alternative, because they have lower emissions of toxic gases in comparison with non-renewable ones. In the group of renewable energies, solar technology has the biggest overall potential, mainly because it is cheap and easy to set. Several solar technologies allow to equip their photovoltaic panels with concentrators, mostly to increase the output power and possibly their efficiency. However, some problems related to the use of concentrators have to be dealt in order to improve the entire photovoltaic system performance. One of these issues is the corrosion of the concentrators, leading to a premature ageing and, consequently an increase in maintenance costs. This problem is going to be analysed in this paper, presenting some simulation from a ray traicing software and also some experimental results, from our own laboratory experiences. The used software allows to trace the solar rays of the concentrator, in order to assess the effect of the defects caused by corrosion due to the ambient circumstances. After it, experimental results will help to analyse this effect and to prove simulation ones.

Insolation And Covid‑19: Protection From The Aggressor

The article reviews the importance of insolation as a factor of prevention and containment of infectious diseases and epidemics. The authors consider insolation not as a mean of curing the Сoronavirus Disease (WHO fairly calls such possibility “a myth”) but as a means to lower the risks of dissemination of the infection, to reduce viability of the virus in the environment, to support human protective immune mechanisms affecting susceptibility of the population as a whole, severity and recovery time, i.e. both sanitary and hygienic and prevention factors of the COVID‑19 epidemic containment. Apart from the germicidal and virucidal sanitising effects of solar rays, the article reviews anti-epidemic capabilities of insolation as a microclimate factor and a psychological and physiological regulator of human protective capabilities as well as the insolation standards as a mechanism of development density regulation. It is impossible to efficiently combat massive dissemination of highly contagious infections without concerted utilisation of all available means and measures: both medical and preventive and organisational. The unprecedented mobilisation of healthcare systems and large-scale restrictive quarantine measures are under special attention of the society. This article reviews the importance of insolation as a universal natural anti-epidemic factor which is undeservedly placed in the end of the list of effective infection combating measures.

Analysis of influence of climatic factors on selecting types of solar panels

The article outlines the problem of the influence of climatic factors on the efficiency of solar panels operation. Not long ago the idea of free electricity seemed incredible. However, the development of technologies rapidly progresses, and the alternative energy captures more and more supporters every day. The popularity of solar panels is growing quite rapidly, since photovoltaic converters are an efficient source of electricity. But for more efficient operation of solar cells it is necessary to create the specific conditions, taking into account the location of the unit. There have been considered the factors of more efficient operation of the photovoltaic converters: the hash climatic conditions and the intensity of solar radiation depending on the angle of reducing the impact of the solar rays onto the solar cell surface.

Construction and Automation of a Microcontrolled Solar Tracker

A solar tracker can be defined as an electromechanical system capable of following the apparent path of the Sun, in order to orient an array of solar panels and/or collectors directly to the solar rays, maximizing the collected energy. Accordingly, the present work describes the process of building and automating a micro-controlled solar tracker. Two mobile structures were built, one equipped with high-precision step motors and four luminosity sensors separated in quadrants by a cross structure, and the other equipped with DC motors and the 275 Wp solar panel, allowing the design and evaluation of the behavior of each structure separately. The control and automation system is centralized in an Arduino MEGA2560 microcontroller, which runs the tracking and positioning algorithms. The built prototype allows us to carry out studies of solar tracking strategies based on sensor and control systems applied to DC motors.