The varied thermal conductivity (insulation) of silica aerogel with heating for different pH has been investigated, it has been depended on ambient pressure drying method in the preparing silica aerogel samples, also six different pH of samples (1, 2, 3, 7, 8 and 9) were treated under five degree of heating with (50,100,150,200 and 250) ᴼC. This technique is important to test the carry-outs hydrophobic silica to temperature without high-quality material changes in the basic characteristics. The hot-wire technique is used in this work to examine the thermal conductivity, Fourier Transform Infrared Spectroscopy (FTIR) depended to characterize the bonds and their artificial by heating. Results show that the samples affected by heating through decreasing the density leading to obtaining more insulation metal, moreover varied pH is an important role in thermal conductivity. The average thermal conductivity of all aerogel samples in this work is (0.01- 0.0061 mW m-10 C-1) this means that it is still below thermal conductivity for air equals to (0.02257) mW m-10 C-1 . Meanwhile, we concluded that the insulation property of silica aerogel is affected by heat treatment and gives it more thermal insulation property.
To achieve optimal plant growth and production under salt stress, some products were added in adequate quantities to give a good yield, especially bean plants which are sensitive to salinity. For this purpose, this experiment was carried out during the spring growing season in 2022 in Baghdad, to study the effects of humic acid, cytokinin, arginine and their interaction with 9 parameters that reflect the overall traits of vegetative growth and yield of common bean plants Phaseolus vulgaris L. var. Astraid (from MONARCH seeds, China). The factorial design with 3 replicates was used, each with 7 plants treated via foliar spraying or by addition to the soil. The first factor included three groups; H0, H1 and H2 (0, 6, 12 Kg.h-1 H
... Show MoreAim of the research is the study of improving the performance of the thermal station south Baghdad and the main reasons for reduced its efficiency. South Baghdad power planet comprises (6) steam turbine units and (18) gas turbine units .The gas turbine units are composed of two groups: the first group is made up of gas units (1,2), each of capacity (123) MW. The design efficiency of gas turbine units is 32%. The actual efficiency data of steam units is 18.3% instead of 45% which is the design efficiency. The main reason for efficiency reduction of gas units is the rejected thermal energy with the exhaust gases to atmosphere, that are (450-510) ℃.The bad type of fuel used (heavy) fuel. Another reason for the low efficiency and has a neg
... Show MoreThermal performance of closed wet cooling tower has been investigated experimentally and theoretically
in this work. The theoretical model based on heat and mass transfer equations and heat and mass transfer balance equations which are established for steady state case. A new small indirect cooling tower was used for conducting experiments. The cooling capacity of cooling tower is 1 kW for an inlet water temperature of 38oC, a water mass velocity 2.3 kg/m2.s and an air wet bulb temperature of 26oC. This study investigates the relationship between saturation efficiency, cooling capacity and coefficient of performance of closed wet cooling tower versus different operating parameters such wet-bulb temperature, variable air-spray water fl
The Experiment was carried out to determine the level vibration transfer in three axes Horizontal X, Lateral Y and Vertical Z direction to seat driver tractor, Vector sum of vibration and Daily Vibration Exposure (8 hours) in seat driver tractor, and vibration in steering wheel tractor, Heart Rate, Systolic and Diastolic blood pressure and temperature were measure to all Drivers before and after used Chisel plow in operation tillage. Statistical analysis system was used, Split-Split Plot Design under Randomized Complete Block Design, Three factors were used in this experiment included Two types of Soil Moist and Dry soil which represented main plot, Three Velocity Tractor was second factor included 1.6,3.5 and 5.4 km/hr and Three Drivers Tr
... Show MoreIt is obvious that the constitutional- political structures which has been emerged in Iraq after the occupation in 2003 frame worked by many sectarian, ethnic, tribal and political orientations, pushing forewords to escalating the contradictions between social- political powers, however, these changes unfortunately result not just destroy and taking apart the political regime and his authority, but the state and his institutions as well, although, did not stamped as wise and rational change for better future to new Iraq and its political, civil and military institutions. Finally, as quick as Iraq start to bisects to sectarian, ethnic and national components according to the new political – social components of Iraq. Indeed, what is req
... Show MoreSoaking dentures with disinfection solutions is an effective way of keeping dentures in a healthy status; however, immersions in these solutions have a negative effect on the bond strength of denture base and denture teeth. The aim of this study was to evaluate the bond strength between denture acrylic teeth and heat-cured Poly (methyl methacrylate) denture base material (with and without nano silica) after disinfection with different chemical disinfectants for a simulated period of six months. One hundred specimens of maxillary central incisors attached to PMMA were divided into two groups; 50 specimens of PMMA without nano silica and 50 specimens of PMMA reinforced with 5 wt% of nano silica. Specimens of each group were immersed in five i
... Show MoreThis research aims to study the performance of comedian in the plays of writer Moliere . The problem of research is to answer the following question: How does comedian Moliere's techniques in a number of his plays and funny acts? The research aims at revealing the means used by the comedian in his performance of a comedic character in the number of Moliere plays.
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... Show MoreAbstract
The Issue of trade policy is one of the most important topics that researchers have been interested in because of its important role in the economy over the ages. This importance has increased due to the increasing of commercial operations at different levels in both developing and developed countries Foreign trade is one of the means of achieving economic development through the economic surpluses resulting from exports and imports, as it is an important pillar of the economy in general and the Iraqi economy in particular, in light of the transformation process that took place for the Iraqi economy in various fields due to the implement
... Show MoreThe paper deals with the traveling wave cylindrical heating systems. The analysis presented is analytical and a multi-layer model using cylindrical geometry is used to obtain the theoretical results. To validate the theoretical results, a practical model is constructed, tested and the results are compared with the theoretical ones. Comparison showed that the adopted analytical method is efficient in describing the performance of such induction heating systems.