Mechanical and thermal properties of composites, consisted of unsaturated polyester resin, reinforced by different kinds of natural materials (Orange peels and Date seeds) and industrial materials (carbon and silica) with particle size 98 µm were studied. Various weight ratios, 5, 10, and 15 wt. % of natural and industrial materials have been infused into polyester. Tensile, three-point bending and thermal conductivity tests were conducted for the unfilled polyester, natural and industrial composite to identify the weight ratio effect on the properties of materials. The results indicated that when the weight ratio for polyester with date seeds increased from 10% to 15%, the maximum Young’s modulus decreased by 54%. When the weight ratio was 5%, the maximum Young’s modulus, yield stress and ultimate tensile stress occurred in the polyester with date seeds. The results of tensile and flexural tests showed that the natural composite material has a higher strength than the industrial material. While the results of flexural tests manifested that the maximum improvement in the flexural strength is obtained for orange peels at 5 wt. %, where the maximum increasing percentage is 153.4% than pure polyester. The thermal conductivity of orange peels decreased to the half value when the weight ratio increased from 10% to 15%. The thermal conductivity for polyester with orange peels was greater than the thermal conductivity of polyester with date seeds with maximum percentage occurred at weight ratio 10% is 14.4%, but the thermal conductivity of the industrial composite material was higher than the natural composite material. Finally, the date seeds composite was a good insulator and it had a reduced heat transfer rate in comparison to the rest of the samples, also the maximum variation of temperature with time occurred in date seeds composite.
This study expands the state of the art in studies that assess torsional retrofit of reinforced concrete (RC) multi-cell box girders with carbon fiber reinforced polymer (CFRP) strips. The torsional behavior of non-damaged and pre-damaged RC multi-cell box girder specimens externally retrofitted by CFRP strips was investigated through a series of laboratory experiments. It was found that retrofitting the pre-damaged specimens with CFRP strips increased the ultimate torsional capacity by more than 50% as compared to the un-damaged specimens subjected to equivalent retrofitting. This indicated that the retrofit has been less effective for the girder specimen that did not develop distortion beforehand as a result of pre-loading. From
... Show MoreThe study aims to develop the awareness of the criteria for judging electronic educational materials among students of educational qualification at Dhofar University over spreading the Corona pandemic through a program based on mini-educational units. The study was applied to (18) students studying Teaching diploma at Dhofar University for the academic year 2020-2021, and their number. They were chosen intentionally. The study resulted in reaching a list of criteria for judging electronic educational materials, roughly (18) criteria in the selection themes and (15) criteria in the use theme. The level of awareness of the sample members with the criteria for selecting and using electronic educational materials and the effectiveness of the
... Show MoreFour new copolymers were synthesized from reaction of bis acid monomer 3-((4-carboxyphenyl) diazenyl)-5-chloro-2-hydroxybenzoic acid with five diacidhydrazide in presence of poly phosphoric acid. The resulted monomers and copolymers have been characterized by FT-IR, 1H-NMR, 13C-NMR spectroscopy as well as EIMs technique. The number averages of molecular weights of the copolymers are between 4822 and 9144, and their polydispersity indexes are between 1.02 and 2.15. All the copolymers show good thermal stability with the temperatures higher than 305.86 C when losing 10% weight under nitrogen. The cyclic voltammetry (CV) measurement and the electrochemical band gaps (Eg) of these copolymers are found below 2.00 ev.
A thermal evaporation technique was used to prepare ZnO thin films. The samples were prepared with good quality onto a glass substrate and using Zn metal. The thickness varied from (100 to 300) ±10 nm. The structure and optical properties of the ZnO thin films were studied. The results of XRD spectra confirm that the thin films grown by this technique have hexagonal wurtzite, and also aproved that ZnO films have a polycrystalline structure. UV-Vis measurement, optical transmittance spectra, showed high transmission about 90% within visible and infrared range. The energy gap is found to be between 3.26 and 3.14e.V for 100 to 300 nm thickness respectivly. Atomic Force Microscope AFM (topographic image ) shows the grain size incre
... Show MoreZinc Oxide transparent thin films (ZnO) with different thickness from (220 to 420)nm
±15nm were prepared by thermal evaporation technique onto glass substrates at 200 with
the deposition rate of (10 2) nm sec
-1
, X-ray diffraction patterns confirm the proper phase
formation of the material. The investigation of (XRD) indicates that the (ZnO) film is
polycrystalline type of Hexagonal and the preferred orientation along (002) plane. The Optical
properties of ZnO were determined through the optical transmission method using ultraviolet-visible spectrophotometer with wavelength (300 – 1100) nm. The optical band gap values of
ZnO thin films were slightly increased from (2.9 - 3.1) eV as the film thickn
In this paper to isolate and study the properties of the cyclooxygenase-2 (EC: 1.14.99.1) enzyme in the blood of a patient suffering from rheumatoid arthritis and study the effect of natural products of the Soapwort on the activity of purified enzyme. The study involves taking 30 ml of blood from an adult woman 40 years old, who suffers from rheumatoid arthritis disease for 13 years. Serum is separated and subjected to a series of purification processes including: precipitation by ammonium sulfate, filtration by centrifugation radiator, dialysis in presence of ammonium bicarbonate, separation using the technology of ion exchange, lipholization and then estimating approximate molecular weight of the enzyme using gel filtration techni
... Show MoreThe education, especially higher education, is an essentially factor in the progress of any society, if we consider the higher education, represents the top of the education`s pyramid which take part in developing the human resources and provide the human staff to raise the productive efficiency, and improve the social , economic level
In order to face the increasing importance of higher education, great capabilities and expenditures must be available in a continous way, such expe
... Show MoreIn this study a DFT calculation on cyclopropanone, cyclopropandione and cyclopropantrione molecules was performed using the basis function 6-31G ** / MP2 and exchange correlation potential B3-LYP. The results showed that the ground state of all molecules geometry belong to the point group ð¶2ð‘£where a vibronic coupling between the vibrational motion with the electronic ground state in the molecule C3O3 this leads to a reduction in symmetry of the molecule fromð·3ℎto ð¶2ð‘£, the driving force of this process is accessing to the electronic configuration complies with Hückel aromatic systems with two electrons. Also in this, study the normal modes of vibration, frequencies, intensities and symm
... Show MoreThe fabricated Photodetector n-CdO /-Si factory thin films Altboukaraharara spatial silicon multi- crystallization of the type (n-Type) the deposition of a thin film of cadmium and at room temperature (300K) and thickness (300 ± 20nm) and the time of deposition (1.25sec) was antioxidant thin films cadmium (Cd) record temperature (673k) for one hour to the presence of air and calculated energy gap optical transitions electronic direct ( allowed ) a function of the absorption coefficient and permeability and reflectivity by recording the spectrum absorbance and permeability of the membrane record within the wavelengths (300 1100nm). was used several the bias ranged between 1-5 Volts. The results showed that this
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