Irrigation Management in GAP

The multisectoral Southeastern Anatolia Project (GAP) is the largest regional developmentplan for one of the less developed parts of Turkey. The GAP project includes the irrigation of 1.7 million ha of land and generation of 27 billion kWh of hydroelectric power with an installed capacity of 7500 MW. In order to optimize the benefits to be obtained from irrigation and to ensure sustainable irrigation in the GAP area, the Government of Turkey has commissioned the GAP Management, and Operation Maintenance study (GAP MOM). The overall MOM model provides an institutional and organizational framework that promotes the most effective development of irrigated agriculture in the GAP region. This goal can be expressed as three major objectives: maximize net benefits, ensure sustainability and be implementable and flexible.     

Bench Scale Studies for Pretreatment of Sanitary Landfill Leachate with Moringa Oleifera Seeds Extract

A laboratory study using a bench scale model of two unit operations involved processes of coagulation (using Moringa oleifera seeds as a natural coagulant) and flocculation-sedimentation have been adopted to treat the leachate from Air Hitam Sanitary Landfill at Puchong in Malaysia. The results of this study has shown, that M. oleifera has a potential for the removal of heavy metals from the leachate, and may be used as a pre-treatment stage for biological treatment to eliminate a portion of the toxic heavy metals, which limit the activity of micro-organisms in the leachate.     

Thermodynamic analysis of an existing coal-fired power plant for district heating/cooling application

In a conventional coal-fired power plant, which is only designed for electricity generation, 2/3 of fuel energy is wasted through stack gases and cooling water of condensers. This waste energy could be recovered by trigeneration; modifying the plants in order to meet district heating/cooling demand of their locations. In this paper, thermodynamical analysis of trigeneration conversion of a public coal-fired power plant, which is designed only for electricity generation, has been carried out. Waste heat potentials and other heat extraction capabilities have been evaluated. Best effective steam extraction point for district heating/cooling system; have been identified by conducting energetic and exergetic performance analyses. Analyses results revealed that the low-pressure turbine inlet stage is the most convenient point for steam extraction for the plant analyzed.     

Numerical Determination of Thermal-Diffusivity Coefficients of Some Nematic Liquid Crystals <Emphasis Type="Italic">in Situ</Emphasis>

In this study, a new experimental study has been implemented to determine the thermal-diffusivity parameters of industrial nematic liquid crystals, 4-pentyl-4′-cyanobiphenyl (5CB) and 4′-octyl-4-cyanobiphenyl (8CB), both numerically by using the finite difference method (FDM) for forward solutions and experimentally by measuring the temperature variation with time and position. The most important parts of this experimental study are the heating system and the liquid crystal cell, which were constructed in-house to determine the temperatures of the materials in situ. Four different positions for local measurements have been studied, and the optimum graph of this variation has been determined. The experimental and theoretical results of this study are consistent with previous measurements performed by means of a conventional thermal technique.     

The effects of Ni-addition on the crystal structure,thermal properties and morphology of Mg-based hydroxyapatites synthesized by a wet chemical method

Four Mg-based hydroxyapatites (HAps) doped with Ni at various amounts of 0, 0.6, 1.2 and 1.8?at% were prepared at the temperature of 870?°C by a wet chemical synthesis. The crystallite size, lattice parameters and crystallinity percent dramatically decreased with adding of Ni. The amount of HAp phase for all the Ni-containing samples is smaller than that of the Ni-free MgHAp. Furthermore, the lattice strain, stress and anisotropic energy density values were affected by the amount of Ni. The differential thermal analysis (DTA) measurements taken in the temperature range from 25 to 1000?°C showed that all the samples are thermally stable. No significant change in the morphology was observed. It was observed that the gradual introduction of Ni caused the Ca-deficiency.     

Comparative energetic and exergetic performance analyses for coal-fired thermal power plants in Turkey

The purpose of this study is to analyze comparatively the performance of nine thermal power plants under control governmental bodies in Turkey, from energetic and exergetic viewpoint. The considered power plants are mostly conventional reheat steam power plant fed by low quality coal. Firstly, thermodynamic models of the plants are developed based on first and second law of thermodynamics. Secondly, some energetic simulation results of the developed models are compared with the design values of the power plants in order to demonstrate the reliability. Thirdly, design point performance analyses based on energetic and exergetic performance criteria such as thermal efficiency, exergy efficiency, exergy loss, exergetic performance coefficient are performed for all considered plants in order to make comprehensive evaluations. Finally, by means of these analyses, the main sources of thermodynamic inefficiencies as well as reasonable comparison of each plant to others are identified and discussed. As a result, the outcomes of this study can provide a basis used for plant performance improvement for the considered coal-fired thermal power plants.     

Visible light photocatalytic water splitting for hydrogen production from N-TiO2 rice grain shaped electrospun nanostructures

We report on the visible light-driven hydrogen production from splitting of water molecules by nitrogen-doped TiO₂ (N-TiO₂) with a rice grain-like nanostructure morphology. The N-TiO₂ nanostructures are prepared using sol-gel and electrospinning methods followed by post-annealing of the composite nanofibers. The nanostructures are characterized by microscopy and spectroscopy. First order rate constants for the visible light-assisted photocatalysis in the degradation of methylene blue (MB) dye are found to be 0.2 × 10⁻³ and 1.8 × 10⁻³ min⁻¹ for TiO₂ and N-TiO₂ (5 wt% of nitrogen), respectively. The N-TiO₂ utilized in water splitting experiments and evaluated hydrogen (H₂) of 28 and 2 μmol/h for N-TiO₂ and TiO₂, respectively. The improvement may be attributed due to the N-doping and higher surface area as ∼70 m²/g.     

Determination of fluorine in milk samples via calcium-monofluoride by electrothermal molecular absorption spectrometry

The determination of fluorine in milk samples via the molecular absorption of calcium mono-fluoride (CaF) was performed using a HR-CS-ETAAS. For this purpose, calcium was pipetted to graphite furnace together with samples. The amount of Ca and the graphite furnace program were optimised. Fluorine was determined in pyrolytically coated platforms at 606.440 nm applying a pyrolysis temperature of 700 °C and a molecule forming temperature of 2250 °C. Finally, applying standard addition technique, F contents of several milk samples were determined. The results obtained by linear calibration and standard addition techniques were significantly different which can be attributed to non-spectral interferences in milk due to matrix concomitants. Therefore, in order to tolerate the errors, the F contents of several milk samples were determined applying standard addition technique. However, since the ingredients of milk samples change for different kinds, the F in each sample was determined from its own standard addition curve. The range of F content for the milk samples were 0.027–0.543 μg mL⁻¹. The limit of detection and characteristic mass of the method were 0.26 and 0.13 ng of F, respectively.