scholarly journals Potential threat of southern Moravia soils by wind erosion

2004 ◽  
Vol 52 (2) ◽  
pp. 33-42 ◽  
Author(s):  
Jana Dufková
Keyword(s):  
Wind Velocity ◽  
Wind Erosion ◽  
Linear Trend ◽  
Soil Surface ◽  
Potential Threat ◽  
Soil Humidity ◽  
Average Wind ◽  
Humidity Index ◽  
Southern Moravia ◽  
Average Wind Velocity

Wind erosion is caused by meteorological factors such as wind, precipitation and evaporation that influence the soil humidity. Erosive-climatological factor expresses wind and humidity conditions of particular landscape. This is an index of the influence of average soil surface humidity and average wind velocity on average soil erodibility by wind. On the basis of average wind velocity and Konček’s humidity index, the values of the erosive-climatological factor for three chosen areas of Czech republic (Telč-Kostelní Myslová, Znojmo-Kuchařovice and Brno-Tuřany), where the pro-cesses of wind erosion could exist, were evaluated. Thus, the change of the factor’s value during the period of 1961 – 2000 was studied. The linear trend for the region of Brno and Znojmo (dry areas) shows increasing threat of soils by wind erosion, the contrary situation is at the humid area (Telč). The results prove the influence of soil humidity on the erosive-climatological factor and hereby the influence on wind erosion spreadout.

scholarly journals Determination of wind erosion next to shelterbelts

2007 ◽  
Vol 55 (5) ◽  
pp. 65-70
Author(s):  
Jana Dufková
Keyword(s):  
Wind Velocity ◽  
Wind Erosion ◽  
Soil Sampling ◽  
Leeward Side ◽  
Soil Resistance ◽  
Soil Humidity ◽  
Clay Particles ◽  
Southern Moravia ◽  
Positive Effect

The influence of shelterbelts on the erodibility of soil by wind was studied at three chosen shelterbelts of Southern Moravia, Czech Republic – near the shelterbelts in the cadastral areas of Dolní Dunajovice, Micmanice and Suchá Loz. Ambulatory measurements of wind velocity as so as soil sampling for soil humidity analyses, non-erodible and clay particles analyses were done during the year of 2006. Subsequently, real erodibility of soil by wind was determined at these three areas. Results of the measurements and calculations verify positive effect of shelterbelts consisted in wind velocity decreasing (at about 78% in average), soil humidity increasing (at about 102% in average) and soil resistance increasing (at about 70% in average) at the leeward side of the shelterbelts.

scholarly journals Integrated spatial assessment of wind erosion risk in Hungary

2016 ◽  
Author(s):  
László Pásztor ◽  
Gábor Négyesi ◽  
Annamária Laborczi ◽  
Tamás Kovács ◽  
Elemér László ◽  
...  
Keyword(s):  
Wind Velocity ◽  
Soil Texture ◽  
Wind Erosion ◽  
National Level ◽  
Wind Tunnel Experiments ◽  
Erosion Risk ◽  
Average Wind ◽  
Meteorological Elements ◽  
Average Wind Velocity ◽  
Insight Into

Abstract. Wind erosion susceptibility of the Hungarian soils was mapped on national level integrating three pillars of the complex phenomenon of deflation. Results of wind tunnel experiments on erodibility of various and representative soil samples were used for the parametrization of countrywide map of soil texture compiled for the upper 5 centimeter layer of soil, which resulted in a map representing threshold wind velocity exceedance. Average wind velocity was spatially estimated with 0.5' resolution using the MISH method elaborated for the spatial interpolation of surface meteorological elements. The ratio of threshold wind velocity exceedance was determined based on values predicted by the soil texture map at the grid locations. Ratio values were further interpolated to a finer 1 ha resolution using sand and silt content of the uppermost (0–5 cm) soil as spatial co-variables. Land cover was also taken into account excluding areas which are not relevant from the aspect of wind erosion (forests, water bodies, settlements etc.) to spatially assess the risk of wind erosion. According to the resulted map of wind erosion susceptibility, about 10 % of the total area of Hungary can be identified as susceptible for wind erosion. The map gives more detailed insight into the spatial distribution of wind-affected areas in Hungary as opposed to former works.

scholarly journals Computational analysis of micro wind turbine with bamboo blades for domestic applications

2021 ◽  
Vol 70 (9&10) ◽  
pp. 150
Author(s):  
J. Suraj Sayed ◽  
P. V. Sreeram ◽  
R. Ramesh Kumar
Keyword(s):  
Wind Turbine ◽  
Pressure Distribution ◽  
Wind Velocity ◽  
Structural Integrity ◽  
Average Value ◽  
Average Wind ◽  
Blade System ◽  
Blade Tip ◽  
Average Wind Velocity ◽  
Domestic Purpose

A domestic purpose micro wind turbine realised using bamboo blade is tested for the power generation at an interval of two years and compared the performance. A CFD analysis of turbine with five blade system is carried out for an average wind velocity of 2.5m/s and structural integrity of the bamboo blade unit based on the pressure distribution is assessed. For the input wind velocity, a stream lined out flow of 5.9 m/s is found when wind turbine rotates at 300 rpm and corresponding pressure distribution is found to be maximum at the expected location of blade tip as129 Pa. The static analysis shows a good margin. For 2.5 m/s, a wind turbine generates an average value of 3.8V with 0.25A (based on 15 <span>Ω</span>/10W load). The wind turbine has produced nearly the same power even after a period of two years.

scholarly journals THE ANALYSIS OF SPEED AND PRESSURE OF WIND IN RAINY WEATHER/VĖJO SLĖGIO IR JO GREIČIO KITIMO LYJANT ANALIZĖ

2001 ◽  
Vol 7 (1) ◽  
pp. 68-72
Author(s):  
Valdas Paukštys ◽  
Vytautas Stankevičius
Keyword(s):  
Surface Layer ◽  
Wind Velocity ◽  
Building Envelope ◽  
Wind Pressure ◽  
Considerable Part ◽  
Exterior Surface ◽  
Lime Mortar ◽  
Average Wind ◽  
Rainy Weather ◽  
Average Wind Velocity

It is not enough to investigate only the effect of wind on buildings, because deterioration of exterior surfaces of buildings is caused by wind and moisture together. A considerable part of rain gets into the exterior surface of enclosure, penetrates deep down and destroys the material of surface layer. The rain passes through enclosure construction and its surface layer due to wind pressure, through joints of the elements and cracks caused by improper transportation as well as by an inaccurate assembling. At present, new multilayer constructional elements are used for building envelope having numerous assembling seams, therefore, the combined influence of rain and wind becomes rather dangerous. It was established that the wind velocity during the rain is one of the main reasons predetermining moisture penetration into protective-decorative walls made of sand-lime brick with split surface, on concrete-lime mortar, according to the analysis of combined influence of the climate by research data [4]. The total effect of rain and wind on the humidity condition of exterior layers is described. Distribution of real wind velocity was estimated according to the data of the last 10 years. It was found that in Kaunas the average wind velocity increases from 3,4 m/s when the rain is absent up to 4,3 m/s and in Vilnius—the average wind velocity increases from 2,9 m/s when the rain is absent up to 3,7 m/s with an increase of approximately 26%, while in Klaipeda the average wind velocity increases from 3,6 m/s when the rain is absent up to 5,1 m/s with an increase of approximately 42%. On the base of the investigations carried out the suggestion is proposed to use the maximum and mean wind velocity values at the rain for estimating the effect of wind to the moisture behaviour in building elements.

Numerical simulation of a wire–plate solid-state fan for ultra-quiet museum display cases

2019 ◽  
Vol 29 (7) ◽  
pp. 1028-1037
Author(s):  
Yijian He ◽  
Xiangyu Chen ◽  
Youming Zheng ◽  
Guangming Chen
Keyword(s):  
Solid State ◽  
Power Consumption ◽  
Wind Velocity ◽  
Heat Dissipation ◽  
Noise And Vibration ◽  
Discharge Electrode ◽  
Average Wind ◽  
Control Technologies ◽  
Museum Display ◽  
Average Wind Velocity

Conventional microenvironment control systems of a museum display case generally use mechanical fans which produce great noise and vibration for heat dissipation of semiconductor air-conditioning units. Solid-state fans (ionic wind) operate with no moving parts and can overcome noise and vibration issues of a microenvironment control system. In this study, a multi-electrode mathematical and physical model of wire–plate solid-state fans was developed, and its performance has been analysed in depth. Simulation results indicate that there is an optimal distance between discharge electrodes ( d), which corresponds to the largest average wind velocity at the exit of the simulation area ( ua). Under the same power consumption, ua and the vertical height from a discharge electrode to a collecting electrode ( H) exhibit a monotonically increasing relationship. Similarly, ua and the radius of a discharge electrode ( r) show a monotonically decreasing relationship. In addition, a manufactured solid-state fan with an average wind velocity of 1.48 m·s−1 shows a noise intensity of 4.3 dB(A), which is considerably lower than that of a mechanical fan, with the same power consumption. These positive results suggest that ultra-quiet microenvironment control technologies of a museum display case can be potentially developed in the near future.

scholarly journals The Influence of Weather Conditions on Rates of Return of Polish Equity Indices

2016 ◽  
Vol 8 (4) ◽  
pp. 183
Author(s):  
Krzysztof Borowski
Keyword(s):  
Wind Velocity ◽  
Atmospheric Pressure ◽  
Snow Depth ◽  
Weather Conditions ◽  
Daily Temperature ◽  
Rates Of Return ◽  
Average Wind ◽  
Minimum Daily Temperature ◽  
Equity Indices ◽  
Average Wind Velocity

<p>The influence of the weather on human behavior have been featured in many, not only scientific publications.  This paper tests the hypothesis that the one-session average rates of return of equity indices (WIG, WIG20, mWIG40 and sWIG80) calculated for the different weather conditions differ in two populations. The atmospheric conditions taken into consideration in this paper are as follows: maximum and minimum daily temperature, sunny hours, rainfall, maximum and average wind velocity, atmospheric pressure, snow depth, sun energy ultraviolet radiation index. In the analyzed period, the impact on the daily rates of return was observed in the case of the following weather conditions: maximum daily temperature, sunny hours, rainfall, maximum wind velocity and atmospheric pressure. The other analyzed weather conditions such as average wind velocity, minimum daily temperature, snow depth, sun energy ultraviolet radiation index, turned out to be irrelevant. Thus, the influence of some weather condition on registered rates of return on the Polish equity markets has been proved.</p>

scholarly journals Impact of Enclosure Boundary Patterns and Lift-Up Design on Optimization of Summer Pedestrian Wind Environment in High-Density Residential Districts

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3199
Author(s):  
Zhengrong Jiang ◽  
Weijun Gao
Keyword(s):  
Wind Velocity ◽  
High Density ◽  
Optimization Strategy ◽  
Wind Environment ◽  
The Sustainable Development ◽  
Evaluation Indexes ◽  
Average Wind ◽  
Practical Guidelines ◽  
Calm Wind ◽  
Average Wind Velocity

A comfortable wind environment favors the sustainable development of urban residential districts and public health. However, the rapid growth of high-rise urban residential districts leads to low wind velocity environments in summer. This study examines the influence of enclosure boundary patterns and lift-up design on the wind environment and proposes an optimization strategy to improve the low wind velocity environment in residential districts in summer. A typical residential district in Hangzhou was selected; the average wind velocity, calm wind zone ratio and comfortable wind zone ratio were selected as the evaluation indexes. The wind environment for different enclosure boundary patterns and lift-up designs were obtained via computational fluid dynamics (CFD) simulations. The results indicate that the pedestrian wind environment is greatly improved in residential districts by reducing the height/width of the enclosure boundary, increasing the permeability rate and adopting a lift-up design in all buildings within residential districts. A combination of permeable railings and lift-up design is recommended; this can increase the average wind velocity and the ratio of comfortable wind zones by 70% and 200%, respectively. This study provides practical guidelines for the optimization of a low wind velocity environment in Chinese high-density residential districts in summer.

scholarly journals Meteorological Factors and the Transmissibility of Hand, Foot, and Mouth Disease in Xiamen City, China

2021 ◽  
Vol 7 ◽  
Author(s):  
Jingwen Xu ◽  
Meng Yang ◽  
Zeyu Zhao ◽  
Mingzhai Wang ◽  
Zhinan Guo ◽  
...  
Keyword(s):  
Wind Velocity ◽  
Meteorological Factors ◽  
Foot And Mouth Disease ◽  
Temperature Threshold ◽  
Transmission Characteristics ◽  
Seasonal Transmission ◽  
Average Temperature ◽  
Average Wind ◽  
Autumn And Winter ◽  
Average Wind Velocity

Background: As an emerging infectious disease, the prevention and control of hand, foot, and mouth disease (HFMD) poses a significant challenge to the development of public health in China. In this study, we aimed to explore the mechanism of the seasonal transmission characteristics of HFMD and to reveal the correlation and potential path between key meteorological factors and the transmissibility of HFMD.Methods: Combined with daily meteorological data such as average temperature, average relative humidity, average wind velocity, amount of precipitation, average air pressure, evaporation capacity, and sunshine duration, a database of HFMD incidence and meteorological factors was established. Spearman rank correlation was used to calculate the correlation between the various meteorological factors and the incidence of HFMD. The effective reproduction number (Reff) of HFMD was used as an intermediate variable to further quantify the dynamic relationship between the average temperature and Reff.Results: A total of 43,659 cases of HFMD were reported in Xiamen from 2014 to 2018. There was a significantly positive correlation between the average temperature and the incidence of HFMD (r = 0.596, p &lt; 0.001), and a significantly negative correlation between the average air pressure and the incidence of HFMD (r = −0.511, p &lt; 0.001). There was no correlation between the average wind velocity (r = 0.045, p &gt; 0.05) or amount of precipitation (r = 0.043, p &gt; 0.05) and incidence. There was a temperature threshold for HFMD's transmissibility. Owing to the seasonal transmission characteristics of HFMD in Xiamen, the temperature threshold of HFMD's transmissibility was 13.4–18.4°C and 14.5–29.3°C in spring and summer and in autumn and winter, respectively.Conclusions: HFMD's transmissibility may be affected by the average temperature; the temperature threshold range of transmissibility in autumn and winter is slightly wider than that in spring and summer. Based on our findings, we suggest that the relevant epidemic prevention departments should pay close attention to temperature changes in Xiamen to formulate timely prevention strategies before the arrival of the high-risk period.

scholarly journals Pengaruh Desain Interior Diffuser Terhadap Peningkatan Performa Diffuser Augmented Wind Turbine (DAWT)

2018 ◽  
Vol 5 (2) ◽  
pp. 70
Author(s):  
Yiyin Klistafani ◽  
Muh Iqbal Mukhsen ◽  
Muh Iqbal Mukhsen
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Interior Design ◽  
Freestream Velocity ◽  
Performance Improvements ◽  
Average Wind ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Suction Flow ◽  
Average Wind Velocity

The main objective of numerical simulation in thisstudies is to determine the effect of diffuser’s interior design onincreasing the diffuser augmented wind turbine (DAWT)performance by observing wind velocity increment. Numericalstudies were carried out using the computational Fluid Dynamics(CFD) method through a two-dimensional steady approach withAnsys Fluent 18.2 and Ansys Workbench 18.2 software. Thepresent studies spesifically investigate the shapes of diffuser,namely flat diffuser and curved diffuser. The studies demonstratethat the curved diffuser generates stronger increment of the windvelocity than flat diffuser (at centreline), which 1.842 times thefreestream velocity, while the flat diffuser is only able to increseup to 1.742 times the freestream velocity. The curved diffusershows the highest increment of the average wind velocity alongdiffuser with the greatest increment of 78.66 % and the flatdiffuser is only able to provide average wind velocity incrementup to 44.81%. The curved interor of diffuser is able to enlarge thewake area, so the effect of the suction flow entering the diffuserbecomes stronger. Therefore, curved diffuser is better to provideDAWT performance improvements.

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