Wasit Journal of Engineering Sciences

Abstract— Silica gel is a substance commonly used in desiccant wheel, which in turn is used in many applications to reduce moisture from the supplied air to a specific space. In this research, the effect of different operational conditions on the performance of silica gel wheel were studied. The desiccant wheel, which has been used, has a diameter of 55 cm and thickness of 20 cm. It contains 34 kg of silica gel and rotate at a speed of 30 rph. The theoretical performance coefficients of the desiccant wheel which have been studied include ,moisture removal capacity(MRC),dehumidification performance(DCOP),latent coefficient of performance (COPlat), and desiccant wheel effectiveness(ϵ_d). The theoretical investigation of these coefficients was done by using Novel Aire Technology software program (Simulation program of desiccant wheel) (2012). While the operational conditions like process air (humid air)inlet temperature between(30 to 43.4)0C, process air inlet humidity ratio between (0.011 to 0.019)kg/kgdry air ,regeneration air inlet temperature between (56.5 to 70)0C,and process air mass flow rate between(0.0814 to 0.199)kg/s. The results shows that the effectiveness and the moisture removal capacity have the same behavior increase with the increasing in mass flow rate from(0.0814 to 0.199) kg/s, humidity ratio from(11 to19)g/kgdry air, and regeneration air temperature from(56 t0 70)oC. But they reduces with increasing of inlet process air temperature from(30 to43.4)oC..

Abstract— With the major advances in technology, the extreme need for more powerful and efficient electronic devices and equipment has increased, that is requiring more heat generation as a result. So, it is necessary to find a cooling method commensurate with heat generated. This leads to the use of the foam heat sink which is considered as one of more powerful cooling methods for this purpose. The target of this work is to numerically investigate the impact of changing the porosity and the ratio between height of the fin respect to its length on base temperature and heat transfer coefficient in the case of natural convection conditions. The dimensions of the foam fins were 100 * 10 in mm (length * width) and the spacing between fins was 8 mm, while the height of fins was variable with ratio ranging from 0.2 to 2.4. The porosity of model was changing from 0.95 to 0.71 with fixed pore density of 10 PPI. The investigations have been performed by using ANSYS Fluent software (R16.1) and the model of a local thermal non-equilibrium (LINE) has been used in the analysis where, the temperature of the solid part in foam matrix and the fluid are solved individually in energy equation. The heat fluxes were various from 4 to 30 W, and air has been used as a working fluid. The results showed that the average improvement in base temperature of the heat sink is 16.7 %, and the maximum enhancement of heat transfer coefficient reaches about 21.3%, when the porosity reduced from 0.95 to 0.79. The highest enhancement in base temperature and heat transfer coefficient obtains when the height to length ratio is (2.2) and estimated by 30 % and 83.8% respectively, compared with the ratio of (0.2).

Abstract— In this study, electronic waste solution was prepared by leached amount of waste in dilute aqua regia (1HNO3: 3HCl). Hydrometallurgy method (solvent extraction) used to extract precious metals (Au+1, Ag+1) from electronic waste by added both of mineral clay (kaolin) and (Polyacrylamide-Kaolin) composite as a adsorbent material to e- waste solution under many of different parameters. These parameters are contact time (i.e.30 min, 60 min, and 120 min), weight in volume unit of adsorbent material (i.e. 5, 10 and 20 g.L-1) which are effects on the adsorption capacity and adsorption efficiency of adsorbent material. Results proved that the adsorption (efficiency and capacity) of Polyacrylamide-Kaolin composite relatively increased than kaolin to extract (Au+1, Ag+1) ions from a neutral e-waste solution. According to the curves of adsorption (i.e. efficiency and capacity), the operation condition preferred at contact time and adsorbent material amount which are equal to 60 min and 10 g.L-1 respectively

Abstract— The solar energy is the most important type of energy. The parabolic dish solar collector (PDSC) is the best type among other solar collectors because it is always tracking the sun movement. The exergy and the energy performances of a PDS were analyzed experimentally and numerically. The effect of different coil geometries and different mass flow rates of heat transfer fluid (HTF) were investigated. The PDS has parabolic dish and receiver with diameter (1.5) m and (0.2) m respectively. Concentration ratio is 56.25. The parabolic polar dish was supported by a tracking system with two axes. The types of the copper absorber were used which are: (spiral –helical) coil (SHC) and spiral-conical coil (SCC). The results showed that the useful energy and thermal efficiency are varying with solar radiation variation. The useful energy varying between (480-765) W for (SHC), the thermal efficiency varying between (35.2-39.8) % for (SHC). Exergy efficiency varying between (6.9 –8.6) %. It was shown that the higher values of useful energy for (spiral – helical) absorber was 0.1L/min flow rate.

Abstract— Recently a large interest has been focused on power quality field due to: disturbances caused by non-linear loads, Increase in the number of electronic devices and renewable energy sources. Power quality measures the fitness of the electric power transmitted from generation to the industrial, domestic and commercial consumers. In a power system voltage distortion introduced by harmonics and voltage sags are the most severe affecting power quality, because of both consumers and utilities are affected by these disturbances. Different methods to enhance the power quality but the custom power device is the most effective and efficient method. One of which is the use of Dynamic Voltage Restorer (DVR). The performance of the DVR based on Fuzzy Neural controller to restore the load voltage to its nominal value under different fault conditions and power disturbances is presented in this paper. Simulation results are carried out using MATLAB/SIMULINK program. The faults and disturbances are initiated at 0.8s and kept till 0.95s.

Abstract—Land use plans in Iraqi cities are traditional and don’t seek to be sustainable and therefore could have negative impacts on the city from the environmental, economic, social and urban aspects. Consequently, the research aims to analyze the current and future of the land use for a set of Iraqi cities to reach the indicators of the gap between traditional and sustainable plans when planning for land uses.

The research conclusion is that most Iraqi cities are highly urban sprawl, both in reality and in the future expansion of the city. That is because it consumes a lot of agricultural land, cities with low population densities that are unsustainable, and most land uses are unsustainable focusing on reducing the agricultural and green lands in the city and increase residential uses (single type with very low density), and expand the areas of the streets that depend on the automated transportation more than sustainable transportation.

The research suggests that sustainable land uses in Iraqi cities should be as follows:

 Residential use: vertical housing pattern 30 %, horizontal housing pattern 15 %.

 Mixed use 12 %.

 Green, open and recreational areas 22 %.

 Sustainable transport 13 %.

 Public, community and government services 8 %.