Evaluation of the Flow Measurement Performance of Compound Sharp-Crested Over-Fall Weirs and Optimized Discharge Measurement in Data Scarce Areas

Water Resources - The hydraulic relationships of flow through the weir of different common shapes were investigated in this study. The hydraulic performances of weirs were carried out...     

New holographic dark energy in modified f(R) Horava-Lifshitz gravity

In this paper, we study the new holographic dark energy model in the framework of modified f(R) Horava-Lifshitz Gravity. We apply correspondence scheme to construct model the in underlying scenario using power-law form of scale factor. To explore accelerated expansion of the universe, some well-known cosmological parameters (equation of state parameter and squared speed of sound) and cosmological planes (ω _Λ – \(\omega'_{\varLambda}\) and statefinder) are discussed for reconstructed model. It is interesting to conclude that these parameters represent phantom behavior of the universe with stable configuration. also, the cosmological planes show compatible results with recent observations for accelerated expansion of the universe.     

Parameters affect foaming and foam stability during foam drilling

The authors presented indoor practice experiments of parameters affect on foaming and foam stability. Experiments were carried out and special equipments were used to determine foaming and foam stability; tests were tabulated and charted. The effects of chemical and physical parameters on foaming and foam stability have been conducted.     

The use of watershed geomorphic data in flash flood susceptibility zoning: a case study of the Karnaphuli and Sangu river basins of Bangladesh

Natural Hazards - The occurrence of heavy rainfall in the south-eastern hilly region of Bangladesh makes this area highly susceptible to recurrent flash flooding. As the region is the commercial...     

The effect of seafloor topography in the Southern Ocean on tabular iceberg drifting and grounding

Antarctic tabular icebergs are important active components in the ice sheet-ice shelf-ocean system. Seafloor topography is the key factor that affects the drifting and grounding of icebergs, but it has not been fully investigated. This study analyzes the impact of seafloor topography on the drifting and grounding of Antarctic tabular icebergs using Bedmap-2 datasets and iceberg route tracking data from Brigham Young University. The results highlight the following points. (1) The quantitative distributions of iceberg grounding events and the tracking points of grounded icebergs are mainly affected by iceberg draft and reach their peak values in sea water with depths between 200 m and 300 m. The peak tracking point number and linear velocity of free-drifting icebergs are found in the Antarctic Slope Front (water depth of approximately 500 m). (2) The area of possible grounding regions of small-scale icebergs calved from ice shelf fronts accounts for 28% of the sea area at water depths less than 2000 m outside the Antarctic coastline periphery (3.62 million km²). Their spatial distribution is mainly around East Antarctica and the Antarctic Peninsula. The area of possible grounding regions of large tabular icebergs with long axes larger than 18.5 km (in water depths of less than 800 m) accounts for 74% of the sea area. (3) The iceberg drifting velocity is positively correlated with ocean depth in areas where the depth is less than 2000 m (R=0.85, P<0.01). This result confirms the effect of water depth variations induced by seafloor topography fluctuations on iceberg drifting velocity.     

Multi-criteria decision-making analysis in selecting suitable plotting positions for IDF curves of storm events

Selecting suitable distributions for rainfall data is usually subjective and complex since it requires decision-makers to consider results from various measures of goodness-of-fit indices. In this study, the VIKOR method in multi-criteria decision-making analysis is modified to select the most suitable plotting positions to represent extreme storm intensities in order to build the intensity–duration–frequency (IDF) curves of storm events. This is done by considering the rankings provided by all goodness-of-fit indices used to obtain a compromise solution. Nine plotting positions are considered: Weibull (W), Adamowski (A), Gringorten (G), Hazen (H) and Gumbel (EV I) and two known plotting positions for generalized extreme value (GEV) distribution using Pearson’s skewness and another two using L-skewness. The IDF curves obtained are compared to a reference IDF curves which was found using the GEV distribution. The mean and median for three goodness-of-fit indices, the coefficient of variation of root mean square error, CV_RMSE, the mean percentage of difference, Δ, and the coefficient of determination, R ², are taken as the criteria for selection process. The results show that six plotting positions, A, H, W, G and the two plotting positions with L-skewness, are equally superior compared to the other three plotting positions.     

Studying the impacts of groundwater evolution on the environment,west Qena city,Egypt

The current research has been conducted to evaluate groundwater aquifers qualitatively in the area located in the Western side of Qena city. The Quaternary aquifer represents the main groundwater source in the study area. It exists under unconfined to semiconfined conditions at depths varying between 4 m due North and 80 m in the South. The chemical analyses of the groundwater samples indicate that 77% of the total samples are fresh and 20% are brackish, while only 3% are saline. In addition, the iso-salinity contour map indicates that the salinity increases towards the central and northern parts of the study area. The total and permanent hardness increase as water salinity increases and vice versa in case of temporary hardness in the groundwater samples. The chemical water types and the ion ratios indicate meteoric origin of groundwater as well as the dissolution of terrestrial and marine salts. The contribution of recent recharge from the River Nile to a few groundwater wells in the study area varies from low to high. In addition, the most recharge sources are from the precipitation. Nitrate concentrations in groundwater increase towards the central and Northern areas significantly elevated in response to increasing anthropogenic land uses. Much of the solutes and physicochemical parameters in these waters are under the undesirable limits of World Health Organization (WHO) for drinking purpose, and a plot of sodium adsorption ratio versus EC shows that about 23% of the groundwater samples are good water quality, about 45% of groundwater samples are moderate quality, and 23% of the groundwater samples are intermediate water class, while the rest of samples (9%) are out of the range.