scholarly journals Analysis of Leakage Current and Insulator Resistivity for Quality Assurance of Medium Voltage Network Polymer Insulators Alumina - SiO2 in Tropical Climate Simulator Room

Teknik ◽  
2021 ◽  
Vol 42 (1) ◽  
pp. 10-19
Author(s):  
Agnes Manik Sari Utami ◽  
Abdul Syakur ◽  
Hermawan Hermawan
Keyword(s):  
Epoxy Resin ◽  
Leakage Current ◽  
Test Chamber ◽  
Tropical Climate ◽  
Climatic Conditions ◽  
Medium Voltage ◽  
Temperature And Humidity ◽  
Voltage Insulator ◽  
Polymer Insulators ◽  
The Relationship

The tropical climate of Indonesia, which has moderately high rainfall, has an impact on the output of outdoor insulators. The presence of chemical particles, pollen, and salt in the air will bind to the insulating material's outer surface and settle, resulting in crystallization that allows the insulating material's surface roughness to increase. One of the insulators that are being produced is an insulator made of epoxy resin. The injection of fillers is used to further improve the durability of the outdoor epoxy resin insulators installed in tropical climatic conditions. Epoxy resin from bisphenol A-epichlorohydrin and polyaminoamide combined with silane, alumina, and SiO2 is used as research materials. The parameters examined were leakage current and resistance to insulation. The use of silane as a hardener will also improve the resistivity on the surface of the insulator, which makes it more difficult to flow or reduces the leakage current. Alumina is well-known for being a solid heat and voltage insulator. The addition of SiO2 to the epoxy resin insulating material increases the insulator's mechanical strength in the form of tensile and compressive strength. With fluctuations in temperature and humidity, the artificial tropical environment is replicated in a test chamber. The value of the leakage current increases with an increase in temperature and humidity. The correlation between air temperature and humidity and insulation resistance is inversely proportional, the higher the temperature applied to the insulator, the lower the insulator resistivity. The same refers to the relationship between air humidity and resistance to insulation. The higher the humidity applied to the insulator, the lower the insulator resistivity. At a test voltage of 11 kV, a humidity of 60%, and a temperature variation of 25oC, the leakage current of epoxy resin insulators is up to 9.2 uA lower than in a factory-made SiR insulator. The leakage current and insulator resistivity's number is already in the good and protected range such that the insulator can be used and reproduce.

scholarly journals Feasibility Study on Electrical Properties of 20 kV Polymeric Insulator Dry Test and Rainwater Test

2021 ◽  
Vol 17 (4) ◽  
Author(s):  
Abdul Syakur ◽  
A.I.W. Nugroho ◽  
Hermawan Hermawan
Keyword(s):  
Epoxy Resin ◽  
Leakage Current ◽  
High Voltage ◽  
Electric Power System ◽  
Insulation Resistance ◽  
Current Test ◽  
Polymer Insulator ◽  
Dry Conditions ◽  
Polymer Insulators ◽  
Ceramic Insulators

Insulator is a very important equipment in an electric power system. Ceramic insulators have been widely used to support conductors in 20 kV power lines. The problem of ceramic insulators is that they are heavy, easily contaminated on the surface and require a lot of energy in the manufacturing process. Therefore, polymer insulators were developed. This paper presents the design of an epoxy resin polymer insulator with Titanium Dioxide (TiO2) as a nanofiller. The leakage current test was carried out in a high voltage laboratory by applying an AC high voltage of 50 Hz to the insulator dry conditions and the insulator wetted by rainwater contaminants. The results of the leakage current test in dry conditions are 487.6 μA, rainwater contaminated conditions are 594.93 μA, insulation resistance in dry conditions is 2.07 G-Ohms, and contaminated conditions are 1.41 G-Ohms. Based on the test results show that the insulator leakage current increases up to 22% when the surface of the insulator is contaminated with rainwater. Meanwhile, the insulation resistance decreased by up to 32% in conditions contaminated with rainwater. The value of leakage current and insulation resistance indicates that the epoxy resin insulator with TiO2 as filler is electrically feasible to use.

ЗУБРЫ НА СЕВЕРЕ РОССИИ — НАСТОЯЩЕЕ И БУДУЩЕЕ

2019 ◽  
pp. 42-44
Author(s):  
I.V. GUSAROV ◽  
V.A. OSTAPENKO ◽  
T.V. NOVIKOVА
Keyword(s):  
Biological Diversity ◽  
Climatic Conditions ◽  
Economic Consequences ◽  
European Bison ◽  
Rare And Endangered Species ◽  
The North ◽  
Rare And Endangered ◽  
Relationship Of ◽  
First Time ◽  
The Relationship

Впервые в мире создана популяция зубров на территории 60 градусов северной широты. В новых климатических условиях разведения и сохранения зубров определены и проанализированы факторы существования вида на севере Европейской части РФ. Выявлены признаки, динамика численности, которые являются составной частью системы, предназначенной для управления биоразнообразием. Интродукция, являясь процессом введения в экосистему нехарактерных для нее видов, может усиливать изменения биоценозов как положительно, так и отрицательно. Насколько быстро и успешно проходит процесс адаптации заселенного вида, и усматривается его влияние на окружающую среду зависит дальнейшее существование зубров и в целом биоразнообразия. В статье обсуждаются вопросы взаимоотношения зубров с другими видами копытных и хозяйственной деятельностью человека, а также дальнейшим использованием зубров в сельскохозяйственном производстве. Пластичность зубров, выявление изменений и их анализ при вселении видов в новые условия обитания необходимы не только для определения развития или деградации биоценозов и в целом экосистемы, но и прогноза социально-экономических последствий интродукции как одного из методов сохранения редких и исчезающих видов фауны.For the first time in the world, a bison population has been created in an area of 60 degrees north latitude. In the new climatic conditions of breeding and preservation of bison, the factors of the species existence in the north of the European part of the Russian Federation are identified and analyzed. The signs, dynamics of abundance, which are an integral part of the system designed to manage biodiversity are identified, since the preservation of biological diversity on the planet is one of the main problems of our time. Introduction, being the process of introducing non-typical species into an ecosystem, can enhance changes in biocenoses, both positively and negatively. The question posing sounds especially when it comes to such a large hoofed animal as the European bison. How quickly and successfully the process of adaptation of the universe takes place and its environmental impact is seen depends on the continued existence of bison and biodiversity in general. The article discusses the relationship of bison with other types of ungulates and human activities, as well as the further use of bison in agricultural production. How these issues will be resolved positively depends on the future of these animals. Thus, the plasticity of bison, the identification of changes and their analysis, with the introduction of species into new habitat conditions is necessary not only to determine the development or degradation of biocenoses and the ecosystem as a whole, but also to predict the socio-economic consequences due to the introduction as one of the methods of preserving rare and endangered species of fauna.

scholarly journals Climate and the spread of COVID-19

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Simiao Chen ◽  
Klaus Prettner ◽  
Michael Kuhn ◽  
Pascal Geldsetzer ◽  
Chen Wang ◽  
...  
Keyword(s):  
Cell Phone ◽  
Visual Inspection ◽  
Climatic Conditions ◽  
Air Travel ◽  
P Value ◽  
Age Dependency ◽  
Similar Extent ◽  
Health Measures ◽  
Age Dependency Ratio ◽  
The Relationship

AbstractVisual inspection of world maps shows that coronavirus disease 2019 (COVID-19) is less prevalent in countries closer to the equator, where heat and humidity tend to be higher. Scientists disagree how to interpret this observation because the relationship between COVID-19 and climatic conditions may be confounded by many factors. We regress the logarithm of confirmed COVID-19 cases per million inhabitants in a country against the country’s distance from the equator, controlling for key confounding factors: air travel, vehicle concentration, urbanization, COVID-19 testing intensity, cell phone usage, income, old-age dependency ratio, and health expenditure. A one-degree increase in absolute latitude is associated with a 4.3% increase in cases per million inhabitants as of January 9, 2021 (p value < 0.001). Our results imply that a country, which is located 1000 km closer to the equator, could expect 33% fewer cases per million inhabitants. Since the change in Earth’s angle towards the sun between equinox and solstice is about 23.5°, one could expect a difference in cases per million inhabitants of 64% between two hypothetical countries whose climates differ to a similar extent as two adjacent seasons. According to our results, countries are expected to see a decline in new COVID-19 cases during summer and a resurgence during winter. However, our results do not imply that the disease will vanish during summer or will not affect countries close to the equator. Rather, the higher temperatures and more intense UV radiation in summer are likely to support public health measures to contain SARS-CoV-2.

scholarly journals Effect of Weave Structure on Thermo-Physiological Properties of Cotton Fabrics

2015 ◽  
Vol 15 (1) ◽  
pp. 30-34 ◽  
Author(s):  
Sheraz Ahmad ◽  
Faheem Ahmad ◽  
Ali Afzal ◽  
Abher Rasheed ◽  
Muhammad Mohsin ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Cotton Fabrics ◽  
Air Permeability ◽  
Climatic Conditions ◽  
Plain Weave ◽  
Weave Structure ◽  
Physiological Properties ◽  
The Relationship

Abstract This paper aims to investigate the relationship between fabric weave structure and its comfort properties. The two basic weave structures and four derivatives for each selected weave structure were studied. Comfort properties, porosity, air permeability and thermal resistance of all the fabric samples were determined. In our research the 1/1 plain weave structure showed the highest thermal resistance making it suitable for cold climatic conditions. The 2/2 matt weave depicted the lowest thermal resistance which makes it appropriate for hot climatic conditions.

Robustness of HPHC Reduction in THS 2.2 Aerosol Relative to 3R4F Reference Cigarette Smoke under Extreme Climatic Conditions

2021 ◽  
Vol 30 (3) ◽  
pp. 109-126
Author(s):  
Laurent Poget ◽  
Catherine Goujon ◽  
Samuel Kleinhans ◽  
Serge Maeder ◽  
Jean-Pierre Schaller
Keyword(s):  
Cigarette Smoke ◽  
Heating System ◽  
Tobacco Product ◽  
Climatic Conditions ◽  
Mainstream Smoke ◽  
Humid Climate ◽  
Experimental Conditions ◽  
Puff Volume ◽  
Temperature And Humidity ◽  
Health Canada

Summary In order to assess robustness for the reduction of harmful and potentially harmful constituent (HPHC) levels generated by the Tobacco Heating System 2.2 (THS 2.2), a heated tobacco product, we compared the aerosol of this product with mainstream smoke from the 3R4F reference cigarette under different conditions of temperature and humidity. The desired climatic conditions were achieved by using an air-conditioning system coupled with the smoking-machine housing. Two extreme climatic conditions were selected, representing a “Hot and Dry” climate (30 °C and 35% relative humidity RH) and a “Hot and Very Humid” climate (30 °C and 75% RH). In addition, aerosol and smoke were generated using the standard conditions recognized for smoking-machine analyses of tobacco products (22 °C and 60% RH), which were close to the climatic conditions defined for “Subtropical and Mediterranean” environments (25 °C and 60% RH). The experimental conditions were chosen to simulate the use of THS 2.2 and cigarettes under extreme conditions of temperature and humidity. HeatSticks and cigarettes taken from freshly opened packs were subjected to short-term conditioning from two to a few more days under the same experimental conditions. We analyzed 54 HPHCs in THS 2.2 aerosol and 3R4F cigarette smoke, generated in accordance with the Health Canada Intense (HCI) standard, using modified temperature and humidity conditions for sample conditioning and machine-smoking experiments. We used a volume-adjusted approach for comparing HPHC reductions across the different climatic conditions investigated. Although a single puffing regimen was used, the total puff volume recorded for the 3R4F cigarette smoke varied due to the influence of temperature and humidity on combustion rate, which justified the use of a volume-adjusted approach. Volume-adjusted yields were derived from HPHC yields expressed in mass-per-tobacco stick normalized per total puff volume. The results indicated that, regardless of the considered climatic conditions, the HPHC levels investigated in THS 2.2 aerosol were reduced by at least 90%, on average, when compared with the concentrations in 3R4F cigarette mainstream smoke. This confirmed the robustness in performance for THS 2.2 to deliver reduced levels of HPHCs under the extreme climatic conditions investigated in this study. In order to further characterize the robustness of these reductions, the lowest reduction performance achieved for individual HPHCs across all climatic conditions was used to define the threshold for a robust reduction. The majority of the 54 HPHCs investigated in THS 2.2 aerosol showed more than 90% reduction. Calculations derived from nicotine-adjusted yields also confirmed robust reductions for all investigated HPHCs. The small differences in absolute reduction between the volume- and nicotine-adjusted approaches were predominantly attributed to a combination of the differences in both nominal nicotine deliveries and total puff volumes between THS 2.2 and 3R4F cigarettes; however, this did not influence the determination of robustness. Our findings confirm the value of this approach for assessing the robustness of a product’s performance under different climatic conditions.

A review of intervention methods used to reduce flying-fox mortalities in heat stress events

2021 ◽  
Vol 43 (2) ◽  
pp. 137
Author(s):  
Matthew Mo ◽  
Mike Roache
Keyword(s):  
Climate Change ◽  
Systematic Review ◽  
Heat Stress ◽  
Evidence Based ◽  
Evaporative Heat Loss ◽  
Temperature And Humidity ◽  
Intervention Trials ◽  
Individual Scale ◽  
The Relationship ◽  
Flying Fox

Heat stress events in Australian flying-fox camps have resulted in significant numbers of flying-fox deaths. The frequency and intensity of such events have increased in recent decades, attributed to anthropogenic climate change. Evidence-based interventions are required to address this growing threat. Responders currently use different combinations of a range of intervention methods. We undertook a systematic review of heat stress interventions, which we classified as either ‘camp-scale’ or ‘individual-scale’. Camp-scale interventions included manual and automated misting of roost vegetation, whereas individual-scale interventions included spraying individual animals or removing them for intensive cooling and rehydration procedures. Our study showed that to date, evaluation of the efficacy of heat stress interventions has been largely anecdotal rather than empirical. This highlights the need for dedicated rigorous studies to evaluate the effectiveness of all the intervention methods described here. It will be especially important to understand the relationship between camp temperature and humidity levels and their influence on flying-foxes’ ability to regulate their body temperature, because high relative humidity reduces the ability of mammals to cool themselves using evaporative heat loss. The development of biophysiological measures such as temperature and humidity indices for different flying-fox species would enable meaningful interpretations of intervention trials under controlled conditions.

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