Influence Of Direct Sunlight Research Articles

Assessment of building daylight systems considering sunscreens under real conditions of the sky

Introduction. Lighting engineering is a complex scientific field which requires the generalization of knowledge in visual comfort evaluation, design and architectural solutions as well as in other areas including the humanities. Global ecological problems and the drive for Sustainable Development require achieving maximum energy efficiency from architectural designers. The tasks of designing daylight systems under real sky conditions cannot be solved without considering the problems of insolation and sunscreens. Russian and foreign standards cover long-put questions about the need to improve the daylight calculation method considering additional light reflected from adjacent surfaces under the clear and partially cloudy skies. The objective of the study is analysis and improvement of the daylight system calculation method considering sunscreens under intermediate sky conditions. Materials and methods. The methods of searching and selecting relevant literature in international abstract databases with well-developed tools for thematic search as well as analytical methods are described. Results. A method for calculating daylight system considering sunscreens under the intermediate sky conditions is suggested. The analysis of the obtained formulae confirmed the proposed theory: under the influence of direct sunlight, reflection from adjacent surfaces significantly increases the daylight level in a room. Conclusions. Assessment of daylight in a room under the intermediate sky conditions should take into account a reflection of the direct sunlight. Correcting the problem under conditions of the CIE overcast sky model in the calculation is associated with the availability of a light climate database. This approach makes it possible to formulate the criteria for a dynamic daylight assessment. Combination of an artificial lighting system with an automatic control mode guarantees the requirements of indoor illuminance and energy saving.

Polyvinyl alcohol/silver nanocomposite films fabricated under the influence of solar radiation as effective antimicrobial food packaging material

As the demand for ready-made food is increasing, it is necessary to develop effective food packaging materials with antimicrobial activity to ensure microbiological safety of food. For this, polyvinyl alcohol (PVA) based active food packaging material reinforced with silver nanoparticles (AgNPs) was prepared by solvent casting. Here, ginger rhizome extract was used as the reducing agent for the rapid in situ reduction of AgNO3 to AgNPs (gAgNPs) within the PVA matrix, under the influence of direct sunlight. Then the films were characterized by SEM, XRD, FTIR and UV-Vis spectrophotometry. Mechanical property analysis of PVA/gAgNP nanocomposite film showed its improved features when compared to neat PVA film. The presence of gAgNPs in the PVA/gAgNP film provided significant UV and light barrier properties together with profound antibacterial activity against the foodborne pathogen Salmonella Typhimurium and Staphylococcus aureus. Considering these excellent results, PVA/gAgNP film can expect to have promising food packaging application.

Poly(vinyl alcohol): Montmorillonite: Boiled rice water (starch) blend film reinforced with silver nanoparticles; characterization and antibacterial properties

Abstract Poly(vinyl alcohol) (PVA) is an excellent film forming polymer used for packaging applications, but it has weak barrier and mechanical properties. Hence improvement in material properties of PVA is expected to enhance its suitability as an ideal food packaging material. For the first time, this study reports the use of boiled rice starch as a blending agent to modify the physicochemical properties of PVA. The aim of the work was to develop montmorillonite (Mt)/PVA/boiled rice starch blend material reinforced with silver nanoparticles (AgNPs) for food packaging application. Highly cost effective method was used for the generation of AgNPs from AgNO3 by using rice starch as a reducing agent. The rapid in situ generation of AgNPs within the polymer matrix, under the influence of direct sunlight, as conducted in this study is a novel approach. The nanocomposite films prepared by solvent casting method were characterized by SEM, XRD, FT-IR and UV–vis spectroscopy analysis. Mechanical, optical, and barrier properties of the nanocomposite films further showed its excellent properties when compared to the neat PVA film. The nanocomposite also showed promising antimicrobial activity against foodborne pathogens Salmonella typhimurium and Staphylococcus aureus. Hence the results suggest the nanocomposite blend developed in the study to be an ideal material for food packaging application.

Sunlight-induced rapid and efficient biogenic synthesis of silver nanoparticles using aqueous leaf extract of Ocimum sanctum Linn. with enhanced antibacterial activity.

BackgroundNanotechnology is now regarded as a distinct field of research in modern science and technology with multifaceted areas including biomedical applications. Among the various approaches currently available for the generation of metallic nanoparticles, biogenic synthesis is of increasing demand for the purpose of green nanotechnology. Among various natural sources, plant materials are the most readily available template-directing matrix offering cost-effectiveness, eco-friendliness, and easy handling. Moreover, the inherent pharmacological potentials of these medicinal plant extracts offer added biomedical implementations of the synthesized metal nanoparticles.ResultsA robust practical method for eco-friendly synthesis of silver nanoparticles using aqueous leaf extract of Ocimum sanctum (Tulsi) as both reducing and capping agent, under the influence of direct sunlight has been developed without applying any other chemical additives. The nanoparticles were characterized with the help of UV-visible spectrophotometer and transmission electron microscopy (TEM). The prepared silver nanoparticles exhibited considerable antibacterial activity. The effects were more pronounced on non-endospore-forming Gram-positive bacteria viz., Staphylococcus aureus, Staphylococcus epidermidis, and Listeria monocytogenes than endospore-forming species Bacillus subtilis. The nanoparticles also showed prominent activity on Gram-negative human pathogenic Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, and plant pathogenic Pantoea ananatis. A bactericidal mode of action was observed for both Gram-positive and Gram-negative bacteria by the nanoparticles.ConclusionsWe have developed a very simple, efficient, and practical method for the synthesis of silver nanoparticles using aqueous leaf extract of O. sanctum under the influence of direct sunlight. The biosynthesis of silver nanoparticles making use of such a traditionally important medicinal plant without applying any other chemical additives, thus offers a cost-effective and environmentally benign route for their large-scale commercial production. The nanoparticles dispersed in the mother solution showed promising antibacterial efficacy.Graphical Sunlight-induced rapid and efficient biogenic synthesis of silver nanoparticles using aqueous leaf extract of Ocimum sanctum Linn. with enhanced antibacterial activity.Electronic supplementary materialThe online version of this article (doi:10.1186/s13588-014-0018-6) contains supplementary material, which is available to authorized users.

Evaluation of Illuminance of Rooms Oriented to Different Cardinal Points

Daylighting levels in interiors are changed every day since sunrise to sunset in dependence on luminous exterior conditions. Indoors are illuminated by diffuse skylight prevailing time of the year in Central European counties while a lot of sunny situations occur mainly during transitional and summer periods. The later can produce overheating as well as glare or disturbing luminance due to excessive sunlight in the space close to windows. If interiors are designed with screened work places the influence of direct sunlight during working time has to be evaluated.The article will present results of computer daylight simulations in a side-lit office room oriented to cardinal points. The study is focused on daylighting evaluation of the room orientation influence on levels under clear sky conditions and compared with results achieved for the CIE overcast sky model. The calculations were run in software Daylight Visualizer 2.6.7. The daylight simulation show that applying the clear sky model for illumination of oriented rooms, the substantial different illuminances can be resulted compared to outputs from the common overcast sky daylight metrics.

A Preliminary Study on the Influence of Direct Sunlight and Shade on Carcasses' Decomposition and Arthropod Succession

A preliminary study was conducted to investigate the effect of direct sunlight and shade on carcass decomposition and arthropod succession in the central region of South Africa. Three pig carcasses (Sus scrofa) were used in this study and were placed in full sunlight, partially in the shade, and in fully shaded conditions. This research was done during the spring season of 2003, from 23 September to 11 November. Internal carcass temperatures, as well as environmental temperatures, were recorded daily and the decomposition rates were compared between direct sunlight versus the partially and fully shaded carcasses. The carcass placed in direct sunlight attracted more arthropods and the decomposition rate was faster compared to those carcasses placed in the shade. Chrysomya chloropyga and Lucilia spp. were the most dominant species on these carcasses. Dermestes maculatus De Geer (Coleoptera, Dermestidae), followed by Necrobia rufipes De Geer (Coleoptera, Cleridae), were present in high numbers during the active decay stage. This study illustrates that shade has an effect on physical decomposition stages. The preliminary results showed that shaded or partly shaded carcasses decompose slower than carcasses exposed to full sunlight. There was no effect on arthropod species succession or development, although the numbers of individuals varied.

THE ROSE BENGAL TEST FOR LIVER FUNCTION

The value of rose bengal as a clinical test for the estimation of liver activity has been proved conclusively by preliminary experiments and observations.1Our purpose in this paper is to describe a simplification of the technic of the test, and to review briefly the types of liver injury which may be revealed by a test of this kind. As has been described in our previous communications, rose bengal is a dye (di-iodo-tetra-chlorfluorescein) of the triphenylmethane series, which is readily soluble in water or saline solution, and which is not toxic for the tissues of the human body. Although Norman and Schmidt2have shown that under the influence of direct sunlight the dye very readily hemolyzes red blood cells in vitro, this photodynamic effect does not seem to occur within the human body to an appreciable extent. Furthermore, it has been our practice to keep tubes of blood

The influence of light and darkness upon the development of xerophthalmia in the rat

The preventive influence of direct sunlight and of radiation with the mercury vapor quartz lamp upon the development of experimental rickets in rats has been demonstrated in experiments reported in previous studies. A logical further step was to determine whether or not direct sunlight and radiation with the mercury vapor quartz lamp would also prevent the development of xerophthalmia in rats fed diets which, under ordinary conditions of roomlight, would lead to the development of both rickets and xerophthalmia and of xerophthalmia alone. If this information could be ascertained it would be a valuable contribution to the study of xerophthalmia and by analogy would suggest either the unity or the divisibility of the factors contained in cod liver oil, which prevent and cure both xerophthalmia and rickets. It was desired also to determine whether or not different combinations or groups of light rays—as for example, direct sunlight, quartz lamp radiations and roomlight—have the same or similar influence upon...

The Influence of Direct Sunlight on Vegetation

THE influence of direct sunlight on vegetation is generally A known, but surely deserves to be a subject of special study. In the following paper we shall only endeavour to describe some facts with relation to this influence. In the first place, the effect of the sun's rays in the tropical regions will be traced, and afterwards in the temperate and arctic zones. The constant high temperature within the tropics is the cause of the plants being less dependent on the direct solar heat than is the case in the greater part of the temperate and cold zones, but, notwitstarid-ing this, there are plants even in the tropical regions requiring for a luxuriant growth the direct rays of the sun.

Action of Light on India-rubber

IT may be in the recollection of some of your readers, that in 1876 I pointed out that the deterioration of ebonite surfaces was due to the combined action of light and air. Some time afterwards it was remarked to me that our laboratory (an old greenhouse) was too light, and as a result all our india-rubber tubes would rapidly deteriorate. This led me to submit some pieces of ordinary black india-rubber to the same treatment as the ebonite in the former experiments. On October 11, 1879, four pieces of caoutchouc connector of 5 mm. internal diameter were taken, two were placed in test-tubes plugged with cotton-wool, and the remaining two inclosed in hermetically sealed tubes. One of the sealed tubes, and one of those plugged with cotton wool were placed in a dark drawer, and the other pair in the laboratory window, with a north aspect, and in such a position that they were not under the influence of direct sunlight in the summer. To-day the specimens were examined. Both the sealed tubes were found to be slightly moist inside, and on opening them an organic odour, like that of an india-rubber shop, was perceived. The caoutchouc which had been exposed to air and light, was covered with a thin brown coating, and on being bent this coating cracked; the end which had been most exposed to the light was rather brittle, and could not be stretched without splitting. The other three specimens were unaltered. All four specimens were slightly acid to test paper, but the quantity of acid was too small to he determined.