PMMA (Poly methyl methacrylate) is considered one of the most commonly used materials in denture base fabrication due to its ideal properties. Although, a major problem with this resin is the frequent fractures due to heavy chewing forces which lead to early crack and fracture in clinical use. The addition of nanoparticles as filler performed in this study to enhance its selected mechanical properties. The Nano-additive effect investigated in normal circumstances and under a different temperature during water exposure. First, tests applied on the prepared samples at room temperature and then after exposure to water bath at (20, 40, 60) C° respectively. SEM, PSD, EDX were utilized for samples evaluation in this study. Flexural strength, shear stress, hardness value were evaluated for all samples, the tests applied periodically at (15, 30, 45) min. Interestingly, it is found that at the normal condition (NC) the cooperation of TiO2 NPs significantly improves the selected properties. The maximum increase is located at 4 wt % of TiO2 NPs addition. The results also showed that temperature increase accelerate the water permeability within all samples thus decrease the mechanical properties. Obviously, a better hardness value determined for the prepared nanocomposite comparing to the control group at the same test condition.
Therapeutic contact lenses TCLs is an approach used to enhance corneal residence time and reduce frequent instillation, which is a problem with eye drops. The problem with CLs is loading of hydrophobic drugs. In this research the CLs were prepared with molecular imprinting MI to enhance the loading of itraconazole, which is used as antifungal drug for fungal keratitis. CLs using different concentration of hydroxyethyl methacrylate HEMA and methacrylic acid MAA were prepared with and without MI using PEGDA (25 μL) and AIBN (37 mg) as crosslinker and initiator respectively. All the prepared CLs were clear and have good folding endurance. MICLs had significantly higher drug loading compared to conventional CLs. The release of i
... Show MoreNanostructural cupric oxide (CuO) films were prepared on Si and glass substrate by pulsed laser deposition technique (PLD) using laser Nd:YAG, using different laser pulses energies from 200 to 600 mJ. The X-ray diffraction pattern (XRD) of the films showed a polycrystalline structure with a monoclinic symmetry and preferred orientation toward (111) plane with nano structure. The crystallite size was increasing with increasing of laser pulse energy. Optical properties was characterized by using UV–vis spectrometer in the wave lengthrange (200-1100) nm at room temperature. The results showed that the transmission spectrum decreases with the laser pulses energy increase. Sensitivity of NO2 gas at different operating temperatures, (50°C,
... Show MoreTodays, World is faced an energy crisis because of a continuous increasing the consumption of fuels due to intension demand for all types of vehicles. This study is one of the efforts dealing with reduce the weight of vehicles by using a new material of sandwich steel, which consists of two skin steel sheets with core of a polymer material. Resistance spot welding (RSW) can be easily implemented on metals; however a cupper shunt tool was designed to perform the resistance welding of sandwich steel with DP800 cover sheets to resolve a non-conductivity problem of a polymer core. Numerical simulations with SORPAS®3D were employed to test the weldability of this new material and supported by many practical experiments. In conclus
... Show MoreAsphalt binder is a thermoplastic material that conducts as an elastic solid at lower service temperatures or throughout fast loading rate. At a high temperature or slow rate of loading, asphalt binder conducts as a different liquid. The classical duplication generates a required to assess the mechanical properties of asphalt concrete at the anticipated service temperature to reduce the stress cracking, which happens at lower temperatures, fatigue, and the plastic deformation at higher temperatures (rutting). In this study, an achievement was made to assess the effect of temperature on the mechanical characteristics of asphalt concrete mixes. A total of 132 asphalt concrete samples were attended utilizing two asphalt cement grades (40-50) a
... Show MoreAsphalt pavement properties in Iraq are highly affected by elevated summer air temperatures. One of these properties is stiffness (resilient modulus). To explain the effect of air temperatures on stiffness of asphalt concrete, it is necessary to determine the distribution of temperatures through the pavement asphalt concrete layers. In this study, the distribution of pavement temperatures at three depths (2cm,7cm, 10cm) below the pavement surface is determined by using the temperature data logger instrument. A relationship for determining pavement temperature as related to depth and air temperature has been suggested. To achieve the objective of this thesis, the prepared specimens have been tested for indirect tension in accordance with
... Show MoreThis study was conducted in the plant protection department/ College of Agriculture/ University of Baghdad to evaluate the efficiency of physical agents ozone, ultraviolet radiation, microwave for destroying afla produced in corn seeds. An isolate af A.flavus producing Aflatoxin B1 was obtained from plant protection dept. college of Agric. University of Baghdad. Results showed destroy toxin AFLA B1 the effect of radiation microwave in the media of Japex degree 80 and 100 co 57.14% and 85.71%, respectively, and for 20 sec, compared to the treatment comparison 0.00% as found significant differences were apparent between transactions and the treatment of comparison, as and notes the existence of a significant dif
... Show MoreBackground: Recently, Poly propylene fibers with and without plasma treatment have been used to reinforce heat cure denture base acrylic but, so far some of properties like tensile strength , wettability and wear resistance not evaluated yet, the aim of the study is to clarify the influence of incorporation of treated and untreated fibers on these properties. Materials and methods: Twenty one specimens were fabricated for every tested property(tensile strength, wear resistance and wettability) that classified into three groups(control, untreated poly propylene fibers reinforced specimens and Oxygen plasma treated group)and for each test sevens amples were used(n=7). Tensile strength was tested using Instron universal testing machine, wear
... Show MoreIn this research we prepared nanofibers by electrospinning from
poly (Vinyl Alcohol) /TiO2. The spectrum of the solution (Emission)
was studied and found to be at 772 nm, several process parameters
were such as concentration of TiO2 , and the effect of distance from
nozzle tip to the grounded collector (gap distance). The result of the
lower concentration of, the smaller the diameter of nanofiber is.
Increasing the gap distance will affect nanofibers diameter
The experiment was conducted to investigate the effect of prey type (Artemia nauplii, mosquito larvae and paramecium) on some reproductive aspects in crustacean zooplankton M. albidus which included reproductive period, post reproductive period, period spend to egg appearance and the period from appearance of egg to nauplii releasing. Results revealed that females fed on mosquito larvae had the highest mean of postreproductive period and lowest mean of the period spend to egg appearance, which differed significantly (P < 0.05) compared with the means of females who fed on Artemia nauplii and paramecium on the other hand the differences were not significant in reproductive period and the period from appearance of egg to nauplii releasing.