Fiber reinforced polymer composite is an important material for structural application. The diversified application of FRP composite has taken center of attraction for interdisciplinary research. However, improvements on mechanical properties of this class of materials are still under research for different applications. In this paper we have modified the epoxy matrix by Al2O3, SiO2 and TiO2 nano particles in glass fiber/epoxy composite to improve the mechanical and physical properties. The composites are fabricated by hand lay-up method. It is observed that mechanical properties like flexural strength, hardness are more in case of SiO2 modified epoxy composite compare to other nano modifiers, were physical properties like density, water absorption are more in case of TiO2 modified epoxy composite. This may be because of smaller particle size of silica compare to others.
The green method was chosen for the preparation of nano iron oxide due to its simplicity, ease of preparation, and purity, compared to other methods. Nano iron oxide was made using a substance that causes precipitation and a coating from the alcoholic extract of orange leaves from Iraq. It was examined structurally and spectrally using several techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning microscopy (FESEM), energy-dispersive X-ray spectroscopy, and UV-Vis spectroscopy. The diagnosis proved that the nano iron oxide was successfully prepared in a spherical form and with an average size of 71.1 nm. The nano iron oxide particles were tested for their ability to remove crystal
... Show MoreThis study was design to investigate the dimensional stability of heat-activated acrylic resin with different methods of flask cooling (15 minutes rapid cooling, one hour bench cooling, four hours delayed deflasking, and 24 hours delayed deflasking) at different time intervals (immediately, two days, seven days, 30 days) after deflasking. Heat-activated acrylic resin was used to prepare acrylic samples. Then, measurement of the distances where achieved between the centers of selected marks in the acrylic samples. They were measured at different time intervals for different methods of flask cooling. The results showed that the group samples of the four hours and 24 hours of delayed deflasking was insignificantly different from the control an
... Show MoreBackground: Determination of sex from an unknown human bone is an important role in forensic and anthropology field. The mandible is the largest and hardest facial bone, that commonly resist postmortem damage and forms an important source of information about sexual dimorphism. Mandibular ramus can be used to differentiate between sexes and it also expresses strong univariate sexual dimorphism. This study was undertaken to assess the usefulness of mandibular ramus as an aid in sex differentiation using CT scanning among Iraqi population. Materials and methods: 3D reconstructed computed tomography scanning of 140 Iraqi Arab subjects, (7 0 males and 70 females) were analyzed with their age range from 20-60 years old. The linear measurements w
... Show MoreIn this paper we prove the boundedness of the solutions and their derivatives of the second order ordinary differential equation x ?+f(x) x ?+g(x)=u(t), under certain conditions on f,g and u. Our results are generalization of those given in [1].
AbstractBACKGROUND: Some cases of vitiligo require melanocyte transplantation, but these surgical techniques have varying degrees of success. OBJECTIVES: To perform melanocytes transplantion in patients with vitiligo using a new needling micrografting technique. PATIENTS and METHODS: This interventional case study took place at the Department of Dermatology and Venereology at Baghdad Teaching Hospital from December 2010 to September 2011. Twelve patients with vitiligo were included. A split-thickness skin graft was taken from the normal area and cut into micropieces ranging from 0.1 mm to 0.3 mm in diameter. The recipient area was anesthetized, and the micrografts were then implanted into the dermis using the needling technique. The number
... Show MoreIn this paper, a new third kind Chebyshev wavelets operational matrix of derivative is presented, then the operational matrix of derivative is applied for solving optimal control problems using, third kind Chebyshev wavelets expansions. The proposed method consists of reducing the linear system of optimal control problem into a system of algebraic equations, by expanding the state variables, as a series in terms of third kind Chebyshev wavelets with unknown coefficients. Example to illustrate the effectiveness of the method has been presented.
The use of Near-Surface Mounted (NSM) Carbon-Fiber-Reinforced Polymer (CFRP) strips is an efficient technology for increasing flexural and shear strength or for repairing damaged Reinforced Concrete (RC) members. This strengthening method is a promising technology. However, the thin layer of concrete covering the NSM-CFRP strips is not adequate to resist heat effect when directly exposed to a fire or at a high temperature. There is clear evidence that the strength and stiffness of CFRPs severely deteriorate at high temperatures. Therefore, in terms of fire resistance, the NSM technique has a significant defect. Thus, it is very important to develop a set of efficient fire protection systems to overcome these disadvantages. This pape
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