scholarly journals Study of resistance to climatic factors of epoxy coatings modified by plant oils and their functionalized derivatives

2019 ◽  
Vol 97 ◽  
pp. 02002 ◽  
Author(s):  
Elena Gotlib ◽  
Anh Nguyen ◽  
Vladislav Yanov ◽  
Alla Sokolova
Keyword(s):  
Climatic Factors ◽  
Solar Irradiation ◽  
Cross Linking ◽  
Photochemical Degradation ◽  
Accelerated Tests ◽  
Epoxy Coatings ◽  
Rubber Seed Oil ◽  
Atmospheric Factors ◽  
The Impact ◽  
Exact Correlation

Epoxy coatings while in-service are regularly exposed to various atmospheric factors including elevated temperature, moisture, solar irradiation, precipitation, fog and others. Those factors accelerate the processes of oxidative and photochemical degradation of epoxy materials which could significantly affect their service life. In the present paper the study of resistance of epoxy materials to climatic factors was carried out in the Artificial weather apparatus simulating external environmental activities by cycles of accelerated tests. It was proven that various types of modifiers exercise influence upon the mass growth of epoxy materials and consequently their sorptive processes. The analysis of investigated results has shown that in epoxy polymer exposed to moisture one could observe competing processes of the growth of cross-linking degree and its plasticization. It was stated that no exact correlation is observed between the degree of cross-linking of epoxy materials and their water fastness and resistance to climatic factors. The authors have proven that outside resistance of epoxy coatings is higher for epoxy compositions modified by soy oil and its functionalized derivatives. Epoxy compositions modified by rubber seed oil exhibited the maximum structural change caused by the impact of climatic factors.

Working conditions and occupational pathology of coal miners in the Arctic

2019 ◽  
pp. 452-457 ◽  
Author(s):  
S. A. Gorbanev ◽  
S. A. Syurin ◽  
N. M. Frolova
Keyword(s):  
Coal Mining ◽  
Working Conditions ◽  
Occupational Diseases ◽  
Climatic Factors ◽  
Coal Mines ◽  
The Arctic ◽  
Morbidity Rate ◽  
Coal Miners ◽  
Increased Risk ◽  
The Impact

Introduction. Due to the impact of adverse working conditions and climate, workers in coal-mining enterprises in the Arctic are at increased risk of occupational diseases (OD).The aim of the study was to study the working conditions, causes, structure and prevalence of occupational diseases in miners of coal mines in the Arctic.Materials and methods. Th e data of social and hygienic monitoring “Working conditions and occupational morbidity” of the population of Vorkuta and Chukotka Autonomous District in 2007–2017 are studied.Results. It was established that in 2007–2017 years, 2,296 ODs were diagnosed for the first time in 1851 coal mines, mainly in the drifters, clearing face miners, repairmen and machinists of mining excavating machines. Most often, the ODs occurred when exposed to the severity of labor, fibrogenic aerosols and hand-arm vibration. The development of professional pathology in 98% of cases was due to design flaws of machines and mechanisms, as well as imperfections of workplaces and technological processes. Diseases of the musculoskeletal system (36.2%), respiratory organs (28.9%) and nervous system (22.5%) prevailed in the structure of professional pathology of miners of coal mines. Among the three most common nosological forms of OD were radiculopathy (32.1%), chronic bronchitis (27.7%) and mono-polyneuropathy (15.4%). In 2017, coal miners in the Arctic had a professional morbidity rate of 2.82 times higher than the national rates for coal mining.Conclusions. To preserve the health of miners of coal mining enterprises, technical measures to improve working conditions and medical interventions aimed at increasing the body’s resistance to the effects of harmful production and climatic factors are necessary.

scholarly journals Investigation of the functional network modifier loading on the stoichiometric ratio of epoxy resins and their dielectric properties

2021 ◽  
Author(s):  
Istebreq A. Saeedi ◽  
Sunny Chaudhary ◽  
Thomas Andritsch ◽  
Alun S. Vaughan
Keyword(s):  
Glass Transition ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Epoxy Resins ◽  
Functional Network ◽  
Cross Linking ◽  
Network Modifier ◽  
Epoxy Resin System ◽  
The Cross ◽  
The Impact

AbstractReactive molecular additives have often been employed to tailor the mechanical properties of epoxy resins. In addition, several studies have reported improved electrical properties in such systems, where the network architecture and included function groups have been modified through the use of so-called functional network modifier (FNM) molecules. The study reported here set out to investigate the effect of a glycidyl polyhedral oligomeric silsesquioxane (GPOSS) FNM on the cross-linking reactions, glass transition, breakdown strength and dielectric properties of an amine-cured epoxy resin system. Since many previous studies have considered POSS to act as an inorganic filler, a key aim was to consider the impact of GPOSS addition on the stoichiometry of curing. Fourier transform infrared spectroscopy revealed significant changes in the cross-linking reactions that occur if appropriate stoichiometric compensation is not made for the additional epoxide groups present on the GPOSS. These changes, in concert with the direct effect of the GPOSS itself, influence the glass transition temperature, dielectric breakdown behaviour and dielectric response of the system. Specifically, the work shows that the inclusion of GPOSS can result in beneficial changes in electrical properties, but that these gains are easily lost if consequential changes in the matrix polymer are not appropriately counteracted. Nevertheless, if the system is appropriately optimized, materials with pronounced improvements in technologically important characteristics can be designed.

scholarly journals Assessing the Sensitivity of Main Crop Yields to Climate Change Impacts in China

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 172
Author(s):  
Yuan Xu ◽  
Jieming Chou ◽  
Fan Yang ◽  
Mingyang Sun ◽  
Weixing Zhao ◽  
...  
Keyword(s):  
Climate Change ◽  
Crop Yield ◽  
Food Production ◽  
Crop Yields ◽  
Climatic Factors ◽  
Climatic Data ◽  
The South ◽  
The North ◽  
Output Elasticity ◽  
The Impact

Quantitatively assessing the spatial divergence of the sensitivity of crop yield to climate change is of great significance for reducing the climate change risk to food production. We use socio-economic and climatic data from 1981 to 2015 to examine how climate variability led to variation in yield, as simulated by an economy–climate model (C-D-C). The sensitivity of crop yield to the impact of climate change refers to the change in yield caused by changing climatic factors under the condition of constant non-climatic factors. An ‘output elasticity of comprehensive climate factor (CCF)’ approach determines the sensitivity, using the yields per hectare for grain, rice, wheat and maize in China’s main grain-producing areas as a case study. The results show that the CCF has a negative trend at a rate of −0.84/(10a) in the North region, while a positive trend of 0.79/(10a) is observed for the South region. Climate change promotes the ensemble increase in yields, and the contribution of agricultural labor force and total mechanical power to yields are greater, indicating that the yield in major grain-producing areas mainly depends on labor resources and the level of mechanization. However, the sensitivities to climate change of different crop yields to climate change present obvious regional differences: the sensitivity to climate change of the yield per hectare for maize in the North region was stronger than that in the South region. Therefore, the increase in the yield per hectare for maize in the North region due to the positive impacts of climate change was greater than that in the South region. In contrast, the sensitivity to climate change of the yield per hectare for rice in the South region was stronger than that in the North region. Furthermore, the sensitivity to climate change of maize per hectare yield was stronger than that of rice and wheat in the North region, and that of rice was the highest of the three crop yields in the South region. Finally, the economy–climate sensitivity zones of different crops were determined by the output elasticity of the CCF to help adapt to climate change and prevent food production risks.

Impact of climatic conditions on the parameters of failure flow of military vehicles

2021 ◽  
pp. 095440702110202
Author(s):  
Nikolaj Dobrzinskij ◽  
Algimantas Fedaravicius ◽  
Kestutis Pilkauskas ◽  
Egidijus Slizys
Keyword(s):  
Climatic Factors ◽  
Armed Forces ◽  
Climatic Conditions ◽  
Operating Conditions ◽  
Technical Equipment ◽  
Factors Affecting ◽  
Military Vehicles ◽  
Equipment Reliability ◽  
Number Of Factors ◽  
The Impact

Relevance of the article is based on participation of armed forces in various operations and exercises, where reliability of machinery is one of the most important factors. Transportation of soldiers as well as completion of variety of tasks is ensured by properly functioning technical equipment. Reliability of military vehicles – armoured SISU E13TP Finnish built and HMMWV M1025 USA built were selected as the object of the article. Impact of climatic conditions on reliability of the vehicles exploited in southwestern part of the Atlantic continental forest area is researched by a case study of the vehicles exploitation under conditions of the climate of Lithuania. Reliability of military vehicles depends on a number of factors such as properties of the vehicles and external conditions of their operation. Their systems and mechanisms are influenced by a number of factors that cause different failures. Climatic conditions represent one of the factors of operating load which is directly dependent on the climate zone. Therefore, assessment of the reliability is started with the analysis of climatic factors affecting operating conditions of the vehicles. Relationship between the impact of climatic factors and failure flow of the vehicles is presented and discussed.

The Lateral Cross-Linking of Polyurethane Using Grafted Epichlorohydrin and the Impact on the Tensile and Thermal Properties

2016 ◽  
Vol 37 (2) ◽  
pp. 323-331 ◽  
Author(s):  
Yong-Chan Chung ◽  
Byung Hee Lee ◽  
Jae Won Choi ◽  
Byoung Chul Chun
Keyword(s):  
Thermal Properties ◽  
Cross Linking ◽  
The Impact

scholarly journals Spatial distribution patterns of soil total phosphorus influenced by climatic factors in China’s forest ecosystems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jie Zhu ◽  
Anchi Wu ◽  
Guoyi Zhou
Keyword(s):  
Spatial Distribution ◽  
Forest Ecosystems ◽  
Climatic Factors ◽  
Critical Role ◽  
Effect Of Temperature ◽  
P Concentration ◽  
Single Effect ◽  
The Impact ◽  
P Distribution ◽  
Total P

AbstractPhosphorus (P) is an important element in terrestrial ecosystems and plays a critical role in soil quality and ecosystem productivity. Soil total P distributions have undergone large spatial changes as a result of centuries of climate change. It is necessary to study the characteristics of the horizontal and vertical distributions of soil total P and its influencing factors. In particular, the influence of climatic factors on the spatial distribution of soil total P in China’s forest ecosystems remain relatively unknown. Here, we conducted an intensive field investigation in different forest ecosystems in China to assess the effect of climatic factors on soil total P concentration and distribution. The results showed that soil total P concentration significantly decreased with increasing soil depth. The spatial distribution of soil total P increased with increasing latitude and elevation gradient but decreased with increasing longitude gradient. Random forest models and linear regression analyses showed that the explanation rate of bioclimatic factors and their relationship with soil total P concentration gradually decreased with increasing soil depths. Variance partitioning analysis demonstrated that the most important factor affecting soil total P distribution was the combined effect of temperature and precipitation factor, and the single effect of temperature factors had a higher explanation rate compare with the single effect of precipitation factors. This work provides a new farmework for the geographic distribution pattern of soil total P and the impact of climate variability on P distribution in forest ecosystems.

Implications of Building Material Choice on Outdoor Microclimate for Sustainable Built Environment

2015 ◽  
Vol 650 ◽  
pp. 82-90 ◽  
Author(s):  
D. Kannamma ◽  
A. Meenatchi Sundaram
Keyword(s):  
Thermal Comfort ◽  
Building Material ◽  
Building Materials ◽  
Climatic Factors ◽  
Outdoor Environment ◽  
Outdoor Thermal Comfort ◽  
Physical Factors ◽  
Physiological Equivalent Temperature ◽  
Material Choice ◽  
The Impact

The climatic conditions in a man-made urban environment may differ appreciably from those in the surrounding natural or rural environs.... each urban man-made buildings, roads, parking area, factories......creates around and above it a modified climate with which it interacts [1].Outdoor thermal comfort has gained importance in thermal comfort studies especially in tropical countries. In country like India, culturally the activities are spread both indoors and outdoors. Therefore the need for ambient outdoor environment gains importance. As there are many factors that contribute to outdoor thermal comfort (climatic factors and physical factors), this study aims in analyzing the impact of building material contribution, in an institutional courtyard. In order to understand the thermal contribution of various building materials and to suggest material choice to designers, ENVIMET is used for simulation purpose. The outdoor thermal comfort index employed in this study is PET (Physiological Equivalent Temperature), calibrated using RAYMAN.

scholarly journals The Spatiotemporal Changes and the Impacts of Climate Factors on Grassland in the Northern Songnen Plain (China)

2021 ◽  
Vol 13 (12) ◽  
pp. 6568
Author(s):  
Liping Wang ◽  
Shufeng Zheng ◽  
Xiang Wang
Keyword(s):  
Climatic Factors ◽  
Climate Factors ◽  
Cultivated Land ◽  
Songnen Plain ◽  
Spatiotemporal Evolution ◽  
High Coverage ◽  
Unused Land ◽  
Spatiotemporal Changes ◽  
The Impact ◽  
Evolution Trend

Grassland is an important ecosystem; the spatiotemporal evolution trend of grassland and its impacts on climatic factors play an irreplaceable role in maintaining regional sustainable development and ecological balance. In this paper, based on the remote sensing images of 1990, 2000, 2010, 2020, and 3S technology, we use the methods of dynamic rate and transfer matrix to analyze the spatiotemporal evolution trend of the northern Songnen Plain (China). The method of grey correlation is used to analyze the impact of climate factors on it. The results showed that the grassland changed dramatically and unevenly across the three periods of 1990–2000, 2000–2010, and 2010–2020, with the biggest change in the last period. The internal conversion of grassland mainly occurred between H-grassland (high coverage grassland) and M-grassland (medium coverage grassland), while the transformation rarely occurred in L-grassland (low coverage grassland) due to its small area. There has been a transfer-in from cultivated land, woodland, and unused land to H-grassland and M-grassland. The grassland transfer-out was mainly from H-grassland and M-grassland to cultivated land and unused land. What’s more, the transformation mainly occurred in Daqing City, Suihua City, Qiqihar city, as well as occurring in the west of Harbin and the southwest of Heihe city. Climate change has exacerbated the reduction of grassland areas. In summary, the spatiotemporal change rates of grassland area in the north of Songnen Plain initially showed a mild decrease and were then followed by a rapid decrease. Climate factors were of great significance to the spatiotemporal changes of grassland, and precipitation had a greater impact on the reduction of grassland. The results can provide meaningful information for grassland change, grassland protection, and management in the northern Songnen Plain.

Assessing the impact of seasonal precipitation and temperature on vegetation in a grass-dominated rangeland

2014 ◽  
Vol 36 (2) ◽  
pp. 185 ◽  
Author(s):  
Fang Chen ◽  
Keith T. Weber
Keyword(s):  
Vegetation Index ◽  
Climatic Factors ◽  
Growing Season ◽  
Vegetation Growth ◽  
Factors Affecting ◽  
Growing Seasons ◽  
Normalised Difference Vegetation Index ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
The Impact ◽  
Precipitation And Temperature

Changes in vegetation are affected by many climatic factors and have been successfully monitored through satellite remote sensing over the past 20 years. In this study, the Normalised Difference Vegetation Index (NDVI), derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Terra satellite, was selected as an indicator of change in vegetation. Monthly MODIS composite NDVI at a 1-km resolution was acquired throughout the 2004–09 growing seasons (i.e. April–September). Data describing daily precipitation and temperature, primary factors affecting vegetation growth in the semiarid rangelands of Idaho, were derived from the Surface Observation Gridding System and local weather station datasets. Inter-annual and seasonal fluctuations of precipitation and temperature were analysed and temporal relationships between monthly NDVI, precipitation and temperature were examined. Results indicated NDVI values observed in June and July were strongly correlated with accumulated precipitation (R2 >0.75), while NDVI values observed early in the growing season (May) as well as late in the growing season (August and September) were only moderately related with accumulated precipitation (R2 ≥0.45). The role of ambient temperature was also apparent, especially early in the growing season. Specifically, early growing-season temperatures appeared to significantly affect plant phenology and, consequently, correlations between NDVI and accumulated precipitation. It is concluded that precipitation during the growing season is a better predictor of NDVI than temperature but is interrelated with influences of temperature in parts of the growing season.

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