In this research, damping properties for composite materials were evaluated using logarithmic decrement method to study the effect of reinforcements on the damping ratio of the epoxy matrix. Three stages of composites were prepared in this research. The first stage included preparing binary blends of epoxy (EP) and different weight percentages of polysulfide rubber (PSR) (0%, 2.5%, 5%, 7.5% and 10%). It was found that the weight percentage 5% of polysulfide was the best percentage, which gives the best mechanical properties for the blend matrix. The advantage of this blend matrix is that; it mediates between the brittle properties of epoxy and the flexible properties of a blend matrix with the highest percentage of PSR. The second stage included reinforcing the best blend matrix of epoxy-polysulfide (the blend matrix with the best percentage of polysulfide resulted from the previous stage), by different volume percentages of short fibers (Carbon& Glass) separately and randomly. The volume percentages of fibers were (2.5%, 5%, 7.5%, and 10%). The third stage included reinforcing the blend composites with highest percentages of carbon and glass fiber, by different weight percentages of nano-particles (Red mud& Fly ash) separately. The weight percentages of particles were (0.5%, 1%, 1.5%, and 2%). The experimental results showed that blending polysulfide rubber with epoxy increased the damping ratio. As for reinforcement materials, they decreased the damping ratio, where glass fiber composites have significantly higher damping ratio than other composites.
The study aimed to study the role of technology in the production of the mural photography, and to develop its concept to the viewer, through the achievement of the aesthetic and functional vision. Through this study, some types of these techniques, which are organically related to architecture, were identified.
The mural photography includes a huge amount of techniques, and methods, and the researcher presented them through five techniques: (AlTamira, Alfresk, acrylic, mosaic, and glass art, which takes the architectural character.
The research consists of:
Methodological framework: research problem, research objectives, research limits, importance of research, and definition of terms.
Theoretical framewo
... Show More
Affinity is a term used to describe the amount of the adhesion bond between asphalt binder and aggregate. Adhesion force may be used as indicator to the amount of energy or work required to breakdown the adhesive bond between asphalt binder and aggregate. In order to study affinity between asphalt binder and aggregate, a modified device is manufacture locally similar to Rolling Bottle Test (RBT) to Predicted the degree of affinity between asphalt binder and aggregate; taking into consideration mineral composition with physical properties of asphalt binder to measure required force to separate asphalt binder from aggregate surface. In this study, suggest new parameters to represent the stripping or affinity phenomena (aff
... Show More
(2)
Nanomaterials enhance the performance of both asphalt binders and asphalt mixtures. They also improve asphalt durability, which reduces resource consumption and environmental impact in the long term associated with the production and transportation of asphalt materials. Thus, this paper studies the effectiveness of Nano Calcium Carbonate (Nano CaCO3) and Nano Hydrated Lime (NHL) as modifiers and examines their impact on ranges from 0% to 10% through comprehensive laboratory tests. Softening point, penetration, storage stability, viscosity, and mass loss due to short-term aging using the Rolling Thin Film Oven Test (RTFO) were performed on asphalt binders. Results indicated a significant improvement in binder stiffness, particularly
... Show More
(34)
(38)
Non-alcoholic fatty liver disease (NAFLD) is one of chronic liver and defines by fat accumulation ≥5% in liver which can progresses to non-alcoholic steatohepatitis (NASH). NAFLD related to obesity as well as non obese individuals. Adiponectin is a cytokine secreted from adipose tissue involved NAFLD pathogenesis and liked with obesity. Irisin is a myokine, has a convenient effect against metabolic diseases such as obesity, disylipemia diabetes type 2 and reversed liver steatosis and may be related with NAFLD. Vitamin D is one of the fat soluble vitamins and more precisely as a pro-hormone through its metabolite (1,25(OH)2 cholecalciferol) the major steroid hormone. After the skin exposure to the light, vitamin D undergoes to
... Show More
(1)
The rise of antibiotic-resistant bacteria necessitates the exploration of novel antimicrobial agents. Yttrium oxide nanoparticles (Y₂O₃) have shown potential due to their unique physicochemical properties and antibacterial activities against various pathogens. This study investigates the cytotoxic and antibacterial effects of Y₂O₃ nanoparticles against Serratia fonticuli and Citrobacter koseri, bacteria isolated from cholangitis patients. Bacterial strains were isolated from bile specimens and confirmed using standard microbiological techniques. The methods of X-ray diffraction (XRD), (SEM), and Frequency transform-infrared spectroscopic (FT-IR) were used to characterize YO₃ particles. Using a microdilution technique, the minimum
... Show MoreThe research examines the awareness of the components of responsible citizenship among primary schoolgirls in Jeddah using a descriptive approach. A test was then prepared, which consists of loyalty, affiliation to homeland, conscious citizenship based on the knowledge of rights, the fulfillment of duties, family roles in education and society revival, homeland and preservation of the components and gains, participation in achievements, and of national heritage. To maintain the validity and reliability of the study, 28-item test of multiple-choice and short essays type was applied to a random sample of (303) female students in the (fourth-fifth-sixth) primary school class in Jeddah. Results have shown that the level of awareness of schoo
... Show More
In this study, the activity concentrations of indoor radon, thoron
and their progeny have been measured in air for 61 different
locations of Al-Maddan city using twin cup dosimeter. Furthermore,
some useful parameters concerning the health hazards have been
estimated; working level month (WLM), annual effective dose (Eff),
and excess lung cancer per million person per year (ELC).The results
show that the values of radon gas levels in the investigated districts
varied from 56.28 to 194.43Bq/m3with an overall average value
132.96Bq/m3, while 0.313 to 1.085 for WLM with an overall average
0.740, respectively. The value of Eff and ELC have been found to
vary from 1.420 to 4.918 mSv/y with an overall average valu
(3)
A Stereomicroscopic Evaluation of Four Endodontic Sealers Penetration into Artificial Lateral Canals Using Gutta-Percha Single Cone Obturation Technique, Omar Jihad Banawi*, Raghad
Water samples from a variety of sources in Kelantan, Malaysia (lakes, ponds, rivers, ditches, fish farms, and sewage) were screened for the presence of bacteriophages infecting
(11)
(8)
A new method for construction ion-selective electrode (ISE) by heating reaction of methyl orange with ammonium reineckate using PVC as plasticizer for determination methyl orange and determination Amitriptyline Hydrochloried drug by formation ion-pair on electrode surface . The characteristics of the electrode and it response as following : internal solution 10-4M , pH (2.5-5) ,temperature (20-30) and response time 2 sec. Calibration response for methyl orange over the concentrationrange 10-3 -10-9 M with R=0.9989 , RSD%=0.1052, D.O.L=0.315X10-9 MEre%=(-0.877- -2.76) , Rec%.=(97.230 -101.711) .