The ceramic composite with different proportions of clay and silica was prepared with a grain size of 70 μm and the weight percentage was selected for four groups (clayx silica100-x) were x q15, 25, 30 and 50. In this manuscript, for each pressured sample, a sintering procedure was carried out for 3 hours under static air and at various sintering temperatures (1000, 1100, 1200, 1400)°C. After sintering, the density, porosity, water absorption, compression strength and thermal conductivity were measured. The best results were obtained using a mixture of 15% clay and 85% silica which were sintering at 1400°C for three hours under air.
This work deals with thermal cracking of slack wax produced as a byproduct from solvent dewaxing process of medium lubricating oil fraction in AL-Dura refinery. The thermal cracking process was carried out at a temperature ranges 480-540 ºC and atmospheric pressure. The liquid hourly space velocity (LHSV) for thermal cracking was varied between 1.0-2.5 . It was found that the conversion increased (61 - 83) with the increasing of reaction temperature (480 - 540) and decreased (83 - 63) with the increasing of liquid hourly space velocity (1.0 - 2.5).
The maximum gasoline yield obtained by thermal cracking process (48.52 wt. % of feed) was obtained at 500 ºC and liquid hour space velocity 1 . The obtaining liquid product at the best op
Density Functional Theory (DFT) calculations were carried out to study the thermal cracking for acenaphthylene molecule to estimate the bond energies for breaking C8b-C5a , C5a-C5 , C5-C4 , and C5-H5 bonds as well as the activation energies. It was found that for C8b-C5a , C5-C4 , and C5-H5 reactions it is often possible to identify one pathway for bond breakage through the singlet or triplet states. The atomic charges , dipole moment and nuclear – nuclear repulsion energy supported the breakage bond .Also, it was found that the activation energy value for C5-H5 bond breakage is lower than that required for C8b-C5a , C5a-C5 , C5-C4 bonds which refer to C5-H5 bond in acenaphthylene molecule are weaker than C8b-C5a , C5a-C5 , C5-C
... 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 MoreTransient displacement of laminated plates under combined load based on Mantari' s displacement field are investigated. The solution is implemented under transient mechanical load (sinusoidal, step and triangular sinusoidal distributed pressures pulse) and thermal buckling for plates with different layer orientation and thickness ratio. Equations of motion based on higher-order theory are derived through Hamilton' s principle, and solved using Naviertype solution for simply supported laminated plates. The results are presented for many effective parameters such as the number of laminate and orientation on the dynamic response of plates. Results show the validity of this displacement field in studying response of laminated thick and
... Show MoreIn this search, a new pyrophosphate technique was proved. The technique was employed to single- nucleotide polymorphisms (SNPs), which diagnosis using a one-base extension reaction. Three Mycobacterium tuberculosis genes were chosen (Rpob, InhA, KatG) genes. Fifty-four specimens were used in this study fifty-three proved as drug-resistant specimens by The Iraqi Institute of Chest and Respiratory Diseases in Baghdad.; also one specimen was used as a negative control. The steps of this technique were by used a specific primer within each aliquot that has a short 3-OH end of the base of the target gene that was hybridized to the single-stranded DNA template. Then, the Taq polymerase enzyme and one of either α-thio-dATP, dTTP, dGTP, or dCTP
... Show MorePyrolysis of virgin polyethylene plastics was studied in order to produce hydrocarbon liquid fuel. The pyrolysis process carried out for low and high-density polyethylene plastics in open system batch reactor in temperature range of 370 to 450°C.
Thermo-gravimetric analysis of the virgin plastics showed that the degradation ranges were between 326 and 495 °C. The results showed that the optimum temperature range of pyrolysis of polyethylene plastics that gives highest liquid yield (with specific gravity between 0.7844 and 0.7865) was 390 to 410 °C with reaction time of about 35 minutes. Fourier Transform Infrared spectroscopy gave a quite evidence that the produced hydrocarbon liquid fuel consisted ma
... Show MoreThe spectroscopic properties, potential energy curve, dipole moments, total charge density, Electrostatic potential as well as the thermodynamic properties of selenium diatomic halides have been studied using code Mopac.7.21 and hyperchem, semi-empirical molecular orbital of MNDO-method (modified neglected of differential overlap) of parameterization PM3 involving quantum mechanical semi-empirical Hamiltonian. The relevant molecular parameters like interatomic distance, bond angle, dihedral angle and net charge were also calculated.
In this paper the effect of thermal annealing on the structural and optical properties of Antimony Selenide (Sb2Se3) is investigated. Sb2Se3 powder is evaporated on clean amorphous glass substrates at room temperature under high vacuum pressure (4.5×10-6 mbar) to form thin films. The structural investigation was done with the aid of X-ray diffraction (XRD) and atomic force microscopy (AFM). The amorphous to polycrystalline transformation of these thin films was shown by X-ray diffraction analysis after thermal annealing. These films' morphology is explained. (UV-Vis ) spectra in ranges from 300 to 1100 nm was used to examine the optical properties of the films .The absorption coefficient and optical energy gap of the investigated films are
... Show MoreA comprehensive practical study of typical mechanical properties of welded Aluminum alloy AA7020-T6 (Al-Mg-Zn), adopting friction stir welding (FSW) technique and conventional metal inert gas (MIG) technique, is well achieved in this work for real comparison purposes. The essences of present output findings were concentrated upon the FSW samples in respect to that MIG ones which can be summarized in the increase of the ultimate tensile strength for FSW was 340 MPa while it was 232 MPa for MIG welding, where it was for base metal 400 MPa. The minimum microhardness value for FSW was recorded at HAZ and it was 133 HV0.05 while it was 70 HV0.05 for MIG weld at the welding metal. The FSW produce 2470 N higher than MIG welding in the bending t
... Show MoreHigh performance self-consolidating concrete HP-SCC is one of the most complex types of concrete which have the capacity to consolidated under its own weight, have excellent homogeneity and high durability. This study aims to focus on the possibility of using industrial by-products like Silica fumes SF in the preparation of HP-SCC enhanced with discrete steel fibers (DSF) and monofilament polypropylene fibers (PPF). From experimental results, it was found that using DSF with volume fraction of 0.50 %; a highly improvements were gained in the mechanical properties of HP-SCC. The compressive strength, splitting tensile strength, flexural strength and elastic modulus improved about 65.7 %, 70.5 %, 41.7 % and 80.3 % at 28 days age, respectively
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