Main Menu
Most read content
Partner Journal
News & Views
Volume 3 : Issue 3, May 2013
| 
| 
Table of Content, 30 May 2013
|
Research Title / |
Article Information / |
Download |
|
Temporal Evolution of Local Scour Depth around Side-by-side Piers
|
Original Article, C13 ABSTRACT:Due to geotechnical and economic considerations, bridge designs often lead to use complex piers or pier groups. The estimation of temporal evolution of scour around bridge pier is important for design of bridge foundation. This study focuses on temporal variation of scour depth around two side-by-side piers with various distances between piers. Based on experimental data, an equation was developed based on new definition of equivalent pier diameter in Kothyari et al. (2007) equation for estimating the time evolution of scour depth by taking into account the effect of space between the piers. The results show that good agreement exists between proposed equation and measured scour data. It is also revealed that by increasing the distance between piers, the equilibrium scour depth around side by side piers decreases and close to values of single pier and scour depth reached to the isolated pier when G/D=6. |
|
|
Sharp-Crested Weir Discharge Coefficient
|
Original Article, C14 ABSTRACT:Weirs are useful and common devices in flow measurements. The essential parameter of each weir is to determine the flow coefficient. In this study, laboratory measurements of the water surface profile, approach flow velocity and flow rate carried out over three different rectangular sharp-crested weirs mounted in a flume. The flow was then numerically simulated by the CFD commercial software Fluent v. 6.2 in several stages. Results show that Fluent can model the flow over this type of weirs preciously. Then the effect of three dimensionless parameters of weir height (H/W), Froude number and Reynolds number on weir discharge coefficient is investigated using experimental and numerical data. For a specific value of these parameters, discharge coefficient is tending to the fixed value of 0.7. |
|
|
The Role of Climatic Factors in the Process of Tourism in the Cities of Kohgiluyeh va Boyer Ahmad Province
|
Original Article, C15 ABSTRACT:Beside cultural, social and economic factors, environmental factors also play an important role in the development of tourism industry and also attracting tourists. Tourism is formed in a geographical atmosphere. This atmosphere has a physical and natural structure including factors such as climate, geology and vegetation and also a human structure with elements such as facilities and equipments that tourists need. The methodology used for the present research is descriptive and analytical and is also based on library surveys and field studies that used a 20 year period data from five weather stations in the province of Kohgiluyeh va Boyer Ahmad (including the dry temperature, the minimum and maximum temperature, average, minimum and maximum relative humidity, precipitation, radiation and wind) to calculate the tourism climate index for this province and it was defined using zoning maps through GIS software. Based on the tourism climate index (TCI) in the Kohgiluyeh va Boyer Ahmad province July is the best month for tourists and in this month the climatic conditions are ideal for tourists. April, May, June, September and October also provide excellent climate conditions. In August and November the climate condition is very good for tourists and December and March are also good for this purpose. But the other months of the year including January and February are cold and the climate conditions are not proper for tourists. In fact the TCI diagram in Kohgiluyeh va Boyer Ahmad has two peaks. One of the peaks starts from the beginning of spring and continues to the end of this season and the other one starts from the beginning of summer and continues to the middle of the autumn. In the summer as the TCI is high and the condition is ideal, a tourist does not need cooling or heating devices and can enjoy their time in this province. |
|
|
The Role of Mosques in Urban Development
|
Technical Note, C16 ABSTRACT:Mosque is the first and the most important base of Muslims in the formation of global government. At the beginning, this base was established by prophet Muhammad (PBUH) as the place of promoting and spreading Islam, a very strong structure that no other places in the world can reach its purity, sanctity and charm. Mosque is the place where people can have privacy with God, a place for meeting beloved and praying Him and confabulate with Him. Lovers in the mosque will never feel tired of staying there and their love will increase and they reach their beloved. It should be mentioned that any place built to pray God and doing Shari affairs of Muslims is mostly valued, but some are more special than other places. |
|
|
Evaluation of Genetic Programming for modeling solute breakthrough curve through the temporal data assignment scenarios
|
Original Article, C17 ABSTRACT:A modeling procedure was assessed in the present paper to investigate the abilities of Gene Expression Programming (GEP) approach for modeling solute breakthrough curve. The evaluation of the GEP method for modeling solute breakthrough curve was carried out through complete data scanning techniques. In this way, a complete scan of the possible train and test set configurations was carried out according to temporal criteria using ‘leave one out’ procedures. The obtained results reveal that the suitable assessment of the model performance should consider a complete temporal and/or spatial scan of the data set used. |
|
|
Regional Flood Frequency Analysis Based on L-Moment Approach (Case Study West Azarbayjan Basins)
|
Original Article, C18 ABSTRACT:Flood estimation with certain frequency is one of the fundamental factors for design of Hydraulic structures, Flood plain, River coastal stabling, Basin management, etc. Accurate estimation of flood frequency discharge increases safety of the structures. L-moment approach was used for flood frequency analysis in west Azarbayjan province basins. For identifying homogeneous regions, the Ward hierarchical cluster method was used. Site data were used for independent testing of the cluster of the station for homogeneity. The west Azarbayjan province divided to four regions. In these regions parameters of the regional frequency distribution were evaluated by L-moment ratios. The L-moment diagram, goodness of fit test, and plotting position methods were used for the selection of appropriate distributions. In west Azarbayjan, Generalized Pareto distribution for region A, Generalized extreme value, Pearson type III and Lognormal distributions for region B, Pearson type III, Lognormal, Generalized extreme value distributions for region C and Lognormal and Generalized extreme value distribution were appropriate for region D. The relative Root Mean Square Error (rRMSE) between observed and estimated data in all stations is small. Regional model evaluated for determination of flood discharge magnitude in different frequency by liner and multiple regression method. |
|
|
Effect of Horizontal Drain Length and Cutoff Wall on Seepage and Uplift Pressure in Heterogeneous Earth Dam with Numerical Simulation
|
Original Article, C19 Abstract:Design of earth dams and their problems are important during construction and after it, because of their potential hazards and failure for downstream population. This study focus on the effectiveness of using horizontal drain and cutoff wall in reducing seepage flow from an assumed heterogeneous earth dam. For this purpose various horizontal drain lengths and cutoff wall depth examine under the earth dam in different location of foundation. Seepage analysis, hydraulic gradient and uplift pressure, are computing by numerical simulation, using Seep/w software. Results show that increasing horizontal drain length, cause slightly in increasing seepage rate and increasing hydraulic gradient. Optimum location of cut off wall for reduction of seepage rate and piping is in the middle of dam foundation. By increasing in cut off wall depth, seepage from earth dam and its foundation is reducing. Different location of cut off wall in dam foundation has little effect on exit hydraulic gradient and always it is less than unity. Installation of cut off wall in middle of foundation, results 19.68 percent decreasing in hydraulic gradient respect to existent of cut off wall in upstream of dam. |
|
|
Effect of Residual Asphalt Content on Creep Strain of Cement Modified Emulsified Asphalt Mixtures
|
Original Article, C20 Abstract:Objective of this paper is to determine the rutting performance of residual asphalt content on cement modified emulsified asphalt mixtures at heavy duty highways. For this purpose, emulsified asphalt specimens with dense graded aggregate were prepared according to Marshall method for emulsified asphalt-aggregate cold mixture design. The specimens were prepared in such a way that portland cement was substituted for mineral filler in an increased percent from 0 % to 6 %. In this way, three asphalt emulsion mixtures with different residual asphalt contents of 4.2 %, 5.2 %, and 6.2 % by the mass of dry aggregate were produced. Static load asphalt creep tests were performed on the specimens. Based on the experimental work, it has been reached that dense graded cement modified emulsion mixtures are of great performance in rutting compared to hot mixtures with the same aggregate grading and bitumen content. Results showed that cement acts as a secondary binder in emulsion mixture. Creep and permanent deformation resistance are all improved by portland cement addition but the resistance to creep deformation of emulsion mixture was decreased by the increase of residual asphalt content. |
|
