Improving the Pressurized Flushing Efficiency in Reservoirs: an Experimental Study

Sediment flushing in many reservoirs of the world is accomplished with low efficiency. In this study, a new configuration was proposed for reservoir bottom outlet to increase the pressurized flushing efficiency. In the new configuration, a projecting semi-circular structure was connected to the upstream edge of bottom outlet. It was observed that by employing the projecting bottom outlet, the sediment removal efficiency increased significantly compared to the flushing via typical bottom outlet. In the case of new-configuration bottom outlet with L _sc /D _outlet  = 5.26 and D _sc /D _outlet  = 1.32, the dimensionless length, width and depth of flushing cone increased 280%, 45% and 14%, respectively, compared to the reference test. The proposed structure can ensure the sustainable use of reservoirs.     

Laboratory Investigation of Stilling Basin Slope Effect on Bed Scour at Downstream of Stepped Spillway: Physical Modeling of Javeh RCC Dam

Stepped spillway and stilling basin are one of the most important energy dissipation structures. Eventhough, most of energy dissipated by these structures, but in skimming flow, the upstream flow motion is nonaerated and the residual energy capable to destroyed structures during floods. In this study, effect of stilling basin slope on bed scour, downstream of Javeh dam was investigating. Experiments performed in hydraulic structures laboratory of the University of Kerman with six different discharges (5, 7, 13, 17, 25 and 30 l/s.m) and five various stilling basin slope (0.02, 0.01, 0, ?0.01 and???0.02). The parameters such as maximum scour depth (d_s), flow velocity (in three point), water depth on upstream and downstream of stepped spillway and stilling basin, the distance of the maximum scour depth to sill (L_s) and the gheometery of scour hole measured. Result shown that when stilling basin slopes was 0.02, the average of maximum relative scour depth, 47% Increased and in ?0.02, 52.2% Decreased. In addition, the distance of maximum scour depth until stilling basin increased by increasing and decreased by decreasing the stilling basin slope.

     

Near infrared measurements of terminal epoxides in polymer resin systems. I. Analytical considerations

Terminal epoxides display a group specific near infrared absorption at 4532 cm^?1. This combination tone is reasonably free of interferences and can be employed to measure oxirane ring concentrations for epoxy coating resin systems during synthesis and crosslinking. With the use of low signal-to-noise FTIR supported by computer data manipulation, chloroform solutions of five commercially available resins were analyzed for epoxide equivalent weight and correlated with results obtained by perchloric acid titrations. The near infrared technique displays linearity for epoxy concentrations of 3.6–20.7 meq/L. Similar results were obtained via a serial concentration study, indicating that the technique is not strongly affected by matrix effects.     

Isolation and Structural Characterization of a Water-Soluble Germination Inhibitor from Scotch Thistle (Onopordum acanthium) Cypselas

Cypsela dormancy in Scotch thistle (Onopordum acanthium) may be affected by the presence of chemical inhibitors. To investigate this phenomenon, a leachate from O. acanthium cypselas was tested for its ability to inhibit germination of the cypselas from which it was derived (i.e., autoinhibition). Leachates varied in their degree of autoinhibition, depending on the cypsela population from which they were prepared. Overall, removal of leachate from a group of O. acanthium cypselas increased their germinability. Using lettuce (Lactuca sativa) cypselas as an indicator species, bioactivity-guided fractionation was used to isolate a water-soluble, para-substituted benzamide from O. acanthium cypselas, which caused germination inhibition. Various chromatographic, spectroscopic, and spectrometric techniques were applied to the characterization of the bioactive compound.     

Pulmonary manifestations in cement workers in Jordan

The literature on obsessive-compulsive disorder (OCD) in children and adolescents is reviewed. The disorder is characterized by obsessions (recurrent troublesome thoughts) and compulsions (ritualized thoughts or behaviors performed repetitively in response to an irresistible urge). OCD is far more common among children and adolescents than was previously believed. Good epidemiological studies from different parts of the world are still needed to determine if prevalence is equally high. Boys seem to have an earlier age of onset of OCD than girls. Male female ratio changed with age of onset, with males predominating in early onset and increasing numbers of females occurring during adolescence. Increasing evidence supports a neurobiological theory for etiology of OCD, specifically a frontal lobe--basal ganglia dysfunction.     

Characterization of solutions and aqueous dispersions of epoxy/amidoamine resins

Molecular weight advancement and epoxy conversion in epoxy-amidoamine resins have been characterized in solutions and in aqueous dispersions using viscosity, light scattering, and near-infrared spectroscopy. By measuring the intensity of the 4532 cm^?1 band in the near infrared, it is possible to determine the concentration of epoxy groups in these resins at low levels in the presence of amine and acid groups as well as solvents and other species. The epoxy-amine reaction in these resins is found to be second order with an activation energy of around 13 kcal/mole. The addition of one mole of carboxylic acid per mole of amine functionality was sufficient to quench the epoxy-amine reaction. Preparation of aqueous dispersions suitable for electrocoat formulation required that the extent of epoxy reaction be within a given range. Although the addition of acid completely quenched the epoxy-amine reaction, a slow side reaction was discovered which consumes epoxy groups and ultimately changes the physical properties of coatings made from these dispersions.     

Developing MSA Algorithm by New Fitness-Distance-Balance Selection Method to Optimize Cascade Hydropower Reservoirs Operation

Water Resources Management - Optimal operation of cascade hydropower reservoirs is a complex high-dimensional engineering problem. Developing an appropriate model to solve such problems requires an...     

Experimental Investigation of Poly-β-Hydroxybutyrate Production by Azohydromonas lata: Kinetics and Artificial Neural Network Modeling

Batch culture of Azohydromonas lata was investigated for the production of intracellular poly-β-hydroxybutyrate (PHB). In order to determine the C:N value of the culture media for maximizing the microbial productivity of PHB, different concentrations of glucose and ammonium chloride were used as carbon and nitrogen sources, respectively. The optimal temperature and shaking rate was obtained at 30°C and 180 rpm, respectively. The maximum intracellular PHB concentration obtained was 5.09 g/l, which was 20% (w/w) of the cell dry weight (CDW) after 72 h. Also, the synthesis of PHB was growth associated with the C:N ratio of 153.71. The maximum calculated Y_p/s was 0.212 (gr/gr) and the specific production rate value after 12 h was 0.264 g/l/h, with 40 and 50 g/l of glucose concentrations, respectively, with 0.5 g/l ammonium chloride kept constant. The chemical composition of the resulting PHB was analyzed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. The Leudeking–Piret model was used for kinetic analysis of the PHB production, the statistical analysis of which was modeled by response surface methodology. An artificial neural network technique was applied for modeling of the microbial production of PHB by A. lata as a function of the glucose concentration and CDW, where the minimum mean square error of the model was 0.0012 and 0.0038 for glucose concentrations of 50 g/l and 40 g/l, respectively, when 0.5 g/l ammonium chloride was kept constant.