scholarly journals 112 Numerical simulation of fog formation and transpotation of air pollutants for the north Kanto mountainous area in summer season

2004 ◽  
Vol 2004.79 (0) ◽  
pp. _1-21_-_1-22_
Author(s):  
Takashi ABE ◽  
Ryusuke YASUDA ◽  
Atsumasa YOSHIDA
2020 ◽  
Vol 15 (4) ◽  
pp. 613-619
Author(s):  
Li Kong ◽  
Yunpeng Zhang ◽  
Zhijian Lin ◽  
Zhongzhu Qiu ◽  
Chunying Li ◽  
...  

Abstract The present work aimed to select the optimum solar tracking mode for parabolic trough concentrating collectors using numerical simulation. The current work involved: (1) the calculation of daily solar radiation on the Earth’s surface, (2) the comparison of annual direct solar radiation received under different tracking modes and (3) the determination of optimum tilt angle for the north-south tilt tracking mode. It was found that the order of solar radiation received in Shanghai under the available tracking modes was: dual-axis tracking > north-south Earth’s axis tracking > north-south tilt tracking (β = 15°) > north-south tilt tracking (β = 45) > north-south horizontal tracking > east-west horizontal tracking. Single-axis solar tracking modes feature simple structures and low cost. This study also found that the solar radiation received under the north-south tilt tracking mode was higher than that of the north-south Earth’s axis tracking mode in 7 out of 12 months. Therefore, the north-south tilt tracking mode was studied separately to determine the corresponding optimum tilt angles in Haikou, Lhasa, Shanghai, Beijing and Hohhot, respectively, which were shown as follows: 18.81°, 27.29°, 28.67°, 36.21° and 37.97°.


2016 ◽  
Vol 9 (2) ◽  
pp. 139-145
Author(s):  
Abdelkrim Benlefki ◽  
Benouada Douaiba ◽  
Azzi Abbes

In this paper the sea breeze dynamics in Oran agglomeration atmosphere, in the north Algeria, is investigated and analyzed by a numerical simulation of Oran agglomeration atmosphere, using SUBMESO model during diurnal cycle of June 24, 2010, in order to predict the spatio-temporal starting of sea breeze, its intensity and relative direction through atmospheric flow variations analysis, and to evaluate the role of thermal circulations on sea breeze direction, intensity and ventilation and its effect on pollutant transport. The study of this area has not been investigated or analyzed in any framework, the numerical simulation was preceded by a topographic and surface data processing in order to generate the grid simulation, with a specific characteristics used by the SUBEMESO and SM2-U (Soil Model for Sub-Meso scales Urbanized) models. This simulation allowed us to know all sea breeze characteristics during the study period.


2019 ◽  
Vol 11 (3) ◽  
pp. 56 ◽  
Author(s):  
Ramón A. Delanoy ◽  
Misael Díaz-Asencio ◽  
Rafael Méndez-Tejeda

The Bay of Samaná, formed by tectonism and sedimentation, is delimited to the north by the peninsula of the same name, to the south by the north slope of the Eastern Mountain Range and Los Haitises National Park, to the east by the Atlantic Ocean, and to the west by the ancient Gran Estero, today the Lower Yuna. There follows a process of continuous degradation by the existing tectonic forces and the sediment contributions by the Yuna, Yabón, and La Yeguada rivers to the south as well as by the landslides of the mountainous area of the Samaná Peninsula, during periods of storms and hurricanes. The coastal area of Samaná Bay has altered by 2.17 km2 at the mouth of the Yuna River from 2003–2015. The high turbidity level has affected coral reefs and marine species.  The  mangroves  are  lost  faster  than  they  are  regenerated  by  the  coastline’s change. Variations in the elemental compositions of calcium and iron show the terrigenous influence on the dynamics of the bay during Extreme Weather Events (EWP) in the river basins that flow into it. Abrupt changes in the rainfall regime produced an equal change in the estuary sedimentation regime, according to the 210Pb. In the 2007–2016 period, a column of sediment that reached 38 cm and a 12 cm to 8.4 km column were deposited 4 km southeast of the municipality of Sánchez and east of the mouth of the Yuna River. The Sedimentary Accumulation Rate is very high, and the content of heavy metals exceeds the threshold values of Table SQuirt.


Author(s):  
Андрей Климов ◽  
Andrey Klimov ◽  
Борис Прошкин ◽  
Boris Proshkin

The study of the form diversity of Siberian poplar species P. nigra , P. laurifolia and P. × jrtyschensis serves as the initial basis for identifying the adaptive capacity of populations, their economically valuable forms and breeding potential. The carried out analysis of the polymorphism of the species in nature and their cultivated forms showed their considerable diversity in terms of their habitual characteristics. It was revealed that the species of P. nigra , P. laurifolia and P. × jrtyschensis have been studied rather irregularly. The paper features an assessment of the form diversity in the North-Western part of the Altai-Sayan mountainous area. The analysis was performed on the basis of qualitative features of the crown, bark, leaves and shoots. Within the studied territory, P. nigra is characterized by the presence of two morphotypes, according to the nature of the pubescence and two distinct forms of bark color. It has been established that the populations of P. laurifolia of the Tom’ river basin are characterized by a greater polymorphism, both according to the diversity of morphotypes of shoots and pubescence, and by the color and structure of the cortex. The white and green bark forms of the laurel poplar are valuable for sustainable construction and selection work. In P. × jrtyschensis , gray bark forms predominate in populations, and its diversity requires a further systematic study.


2020 ◽  
Vol 145 ◽  
pp. 14914-14929
Author(s):  
Pocoun Damè Kombienou ◽  
Ismaël Imorou Toko ◽  
Gustave Dieudonné Dagbenonbakin ◽  
Guy Apollinaire Mensah ◽  
Brice Augustin Sinsin

L’étude aborde la dynamique de l’utilisation des terres à travers l’évolution des emblavures et de la production des principales cultures, puis l’impact des activités agricoles sur l’environnement et les conditions de vie des populations. Objectif : L’objectif global de l’étude était d’évaluer les impacts socio-environnementaux des activités agricoles dans les Communes de Natitingou, Boukombé, Tanguiéta et Toucountouna en zone de montagnes au nord-ouest de l’Atacora au Bénin. Méthodologie et résultats : Les méthodes utilisées étaient les enquêtes exploratoires, les diagnostics participatifs, les sondages d’opinion et les analyses statistiques tels que la variance suivant le test de Tukey et le test de corrélation. Au total, 400 agriculteurs sont sélectionnés au hasard et interrogés dans huit villages des quatre communes à l'aide d'un questionnaire structuré pour obtenir des données relatives aux nombres de cultures produites sur une même parcelle, aux différentes pratiques agricoles, à l'utilisation des engrais minéraux, à l’adoption des techniques endogènes et exogènes de gestion et de conservation de la fertilité des sols dans le milieu. Les résultats ont montré que les systèmes de productions agricoles étaient encore de type extensif et itinérant sur brûlis. Les cultures étaient mises en place en pure et en associations entre avril et décembre avec une prééminence des céréales qui ont occupé environ 52 % des superficies emblavées. Les productions étaient plus en fonction des superficies que de l’intensification agricole. Les causes de dégradation des sols, la production, ont été collectées lors des entretiens collectifs et individuels. Les impacts de la production agricole se traduisaient surtout entre autres, par la disparition du couvert végétal, la baisse de la fertilité des sols et la pollution de certains cours d’eau aux bords desquels se réalisaient des activités à dominance agricole. Conclusion et application des résultats : Certaines activités telles que l’utilisation des engrais chimiques et les feux de végétation ont résolu d’une manière ponctuelle certains problèmes comme l’amélioration des rendements agricoles et l’augmentation des revenus, mais elles n’ont pas duré dans le temps. Au fil des années, ces activités ont eu un impact négatif sur le milieu et les conditions de vie des populations. L’intensification agricole basée sur la vulgarisation et l’adoption des technologies plus productives et respectueuses de l’environnement, efficientes, facilement applicables par les producteurs, demeure l’une des stratégies pour garantir une utilisation durable des ressources naturelles. Mots clés: Bénin, Atacora, activités agricoles, impacts socio-environnementaux et dégradation des sols ABSTRACT The study approaches the dynamics of the land use through the evolution of cultivated area and the production of the principal crops, then the impacts of the agricultural activities on the environment and the living conditions of the population. Objective: The total objective of the study was to evaluate the socio-environmental impacts of the agricultural activities in the Communes of Natitingou, Boukombe, Tanguieta and Toucountouna in mountainous area in the North-Western of Atacora in Benin. Methodology and Results: The methods used were the exploratory investigations, the participative diagnoses, the opinion polls and statistical analyses such as the variance according to the test of Tukey and the test of correlation. On the whole, 400 farmers were selected randomly and questioned in eight villages of the four communes using a structured questionnaire to obtain relative data with the numbers of cultures produced on the same piece, with various husbandries, with the use of mineral manures, the adoption of the endogenous and exogenous technical of management and conservation of the fertility of the grounds in the medium. The results showed that agricultural production systems were still extensive and itinerant on slash-and-burn. Crops were established in pure and association between April and December with a pre-eminence of cereals, which accounted for about 52% of the area. Productions were more based on acreage than agricultural intensification. The causes of soil degradation, production, were collected during collective and individual interviews. The impacts of agricultural production were mainly reflected in the disappearance of vegetation cover, the decline in soil fertility and the pollution of certain rivers along which agricultural-dominated activities were carried out. Conclusion and application of results: Some activities such as the use of chemical fertilizers and wildfires have solved problems such as improving agricultural yields and increasing incomes on an ad hoc basis, but they didn’t last. Over the years, these activities have negatively affected the environment and living conditions of the population. The agricultural intensification based on the popularization and the adoption of more productive and environment friendly technologies, easily applicable by the producers, remains one of the strategies to guarantee a durable use of the natural resources. Keywords: Benin, Atacora, agricultural activities, socio-environmental impacts and impoverishment of the soil


2003 ◽  
pp. 55-75 ◽  
Author(s):  
Ann Forsten ◽  
Vesna Dimitrijevic

A review of the fossil horses of the genus Equus from the central Balkans, a mountainous area comprising Serbia and Montenegro, is presented in this paper. The time period covered by the finds is from the late Early to and including the Late Pleistocene, but the record is not complete: the dated finds are Late Pleistocene in age, while Early and Middle Pleistocene are poorly represented. The horses found resemble those from neighbouring countries from the same time period, probably showing the importance of river valleys as migration routes. The Morava River valley runs in a roughly south-to-north direction, connecting, via the Danube and Tisa River valleys the Hungarian Pannonian Plain in the north with northern Greece in the south, via the Vardar River valley in Macedonia. In Pleistocene, large mammals, including horses, probably used this route for dispersal.


1995 ◽  
pp. 2625-2630
Author(s):  
J. W. S. Longhurst ◽  
S. J. Lindley ◽  
D. E. Conlan

2017 ◽  
Vol 139 ◽  
pp. 00090
Author(s):  
Cheng Liu ◽  
Zhonghu Yuan ◽  
Yingkui Du ◽  
Chunhe Shi ◽  
Yutong Gao ◽  
...  

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