排序方式： 共有6条查询结果，搜索用时 93 毫秒
1
1.
Ummul Fahri Abdul Rauf Panlop Zeephongsekul 《Theoretical and Applied Climatology》2014,115(1-2):153-166
The main objective of this study is to investigate the joint distribution of rainfall severity and rainfall duration in the state of Victoria, Australia, based on monthly rainfall data from selected rain-gauge stations which are located in the north-eastern and south-western parts of the state, during the period from 1950 to 2010. Traditional approach for considering the joint distribution of rainfall characteristics using standard bivariate modeling presents some limitations that can be circumvented by using Copula models. Archimedean and extreme-value copulas will be used to obtain the bivariate distribution of rainfall severity and duration. The Standard Precipitation Index (SPI), which is employed extensively to quantify rainfall severity, will be discussed in detail. Several goodness of fit tests will be performed to find the best fitting copulas and the results will be summarized. The final fitted copulas will then be applied to obtain the joint and conditional return periods from a minimum of two years to one hundred years of rainfall events in Victoria. 相似文献
2.
Dissolved oxygen is one of the most important water quality parameters. Aeration improves the water quality by maintaining good dissolved oxygen levels in water. Dissolved oxygen enters water by entrainment of air bubbles. A method of aeration that has become popular in recent years is the venturi aeration. In the present paper, experimental studies were conducted to investigate the effect of the location of the air hole in venturi tubes upon air injection. It was observed from the results that the location of the air hole playes a significant role for the air injection. The optimal air hole location that maximized the air injection in venturi aerators was determined. 相似文献
3.
Numerical investigation of stochastic response of an elevated water tank to random underground blast loading 总被引：2，自引：2，他引：0
Kemal Hacıefendioğlu Kurtuluş Soyluk Fahri Birinci 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(4):599-607
This paper presents a stochastic finite element seismic response study of a water tank subjected to random underground blast-induced
ground motion. Such tanks contain water and hazardous chemical substances, which implies significant risk to human life, serious
environmental pollution, and considerable economic loss. The random blast-induced ground motion is represented by power spectral
density function and applied to each support point of the three dimensional finite element model of the elevated water tank–fluid
interaction system. A parametric study is conducted to estimate the effects of the blast-induced ground motion on the stochastic
response of the elevated water tank system. Therefore, the analyses are carried out for different values of the charge weight
and the distance from the charge centre. Additionally, in order to investigate the effect of the fluid on the stochastic response
of the elevated water tank, three cases with different water levels are considered in the analyses. Finally, it is observed
that underground blast loading considerably changes the stochastic behavior of the elevated water tank system. 相似文献
4.
Modern coastal areas have natural and transported rocks (armourstone) on which various types of organisms live. Burrowing,
boring and feeding by these organisms can destroy or modify the coastal rocks and hence change the coastal morphology. Two
rock types and three dominant types of organisms have been studied in Mersin Bay, Eastern Mediterranean of southern Turkey.
In this study area, Plio-Quaternary conglomerates and variously aged limestone armourplates have been affected by Phoronida
worms, bivalve Brachidontes pharaonis (Fischer P. 1870) and the limpet Patella sp. Phoronida colonies were found covering the hard substratum as a mat and form tubular endolithes of 35.0 mm depth and
1.5 mm diameter, whilst Brachidontes pharaonis (Fischer P. 1870) form 44 mm deep vase-shaped gastrochaenolites. The bioerosive activity of Limpet Patella sp., found intertidal and within the spray zone, cannot be significantly observed on the rocks over short time periods. The
soft sandy matrix of the conglomerates present were found to disintegrate by bioerosional processes, with the released gravels
being transported and deposited onto the beach. Within the armourstone limestone blocks, a maximum of 44.0 mm deep holes developed
after 50–60 years. However, these biological activities do not threaten the stability of the blocks due to their hard and
homogeneous internal structure. Furthermore, the organism colonies that cover these rocks as a strong mat (maximum 29.0 mm)
act to protect their surfaces from further biological attack and wave action. 相似文献
5.
Fahri elik 《Ocean Engineering》2007,34(16):2138-2145
A numerical study is carried out for calculating effect of the wake equalizing duct (WED) on the propulsion performance of a chemical tanker. Analysis is performed using a CFD tool based on the solution of Reynolds averaged Navier–Stokes (RANS) equation. Computations are carried out for several arrangements of WED for a number of ship speeds. Total 56 runs are achieved, and the results are compared with each other. It can be concluded from this study that propeller characteristics and resistance of the ship are slightly affected by the presence of the WED, but an additional thrust is produced by the WED. It is also found that the maximum gain obtained by using an appropriate WED design is about 10%. 相似文献
6.
The ecological quality of water depends largely on the amount of oxygen that the water can hold. The higher the level of dissolved oxygen, the better the quality of a water system. By measuring dissolved oxygen, scientists determine the quality of water and health of an ecosystem. Oxygen enters water by entrainment of air bubbles. Many industrial and environmental processes involve the aeration of a liquid by such entrainment of air bubbles. Venturi aeration is a method of aeration that has become popular in recent years. When a minimal amount of differential pressure exists between the inlet and outlet sides of a venturi tube, a vacuum (air suction) occurs at the suction holes of the venturi tube. The present paper describes the effect of Reynolds Number, air inlet hole diameter, inlet diameter, pipe length, and angle of pipe downstream of the venturi tube, on the air injection rate. It is observed from the results that venturi tubes have high air injection efficiencies. Therefore, venturi tubes can be used as highly effective aerators in ponds, lakes, fish hatcheries, water treatment plants, etc. 相似文献
1