Study the Effect of Absorption Solution for Same Composite Polymeric Material
In this paper concerns an investigation of absorption solution in materials of polymeric composite were prepared two types of the matrix material were used (PE,PVC). Also two types of fiber were used (woven and short glass fiber ).with volume fraction 20%. The sample were immersed in different solution (NaCO3-KOH –HCL , Normality 0.5 N) for equal time at constant temperature (room temperature ±20C ) . The result show that the relative mass gain increased with increasing the immersion time till they tend saturation moisture mass after that the relative mass gain decreased . The result show that sample in (KOH)solution had higher mass gain while the sample immersed in (HCL) had lower mass gain .Also the results show that the sample immersed in (NaCO3) has maximum diffusion coefficient which means minimum absorption resistance, while the sample immersed in (HCL) has minimum diffusion coefficient which means maximum absorption resistance.
The use of water absorption kinetic data to predict laminate property changes
Abstract A method is described for the prediction of mechanical property changes in laminates as a consequence of prolonged immersion in water. The kinetics of moisture absorption by a polyester resin and its glass fibre-reinforced laminates have been determined for absorption at temperatures between 30 and 100°C. Changes in tensile strength and modulus of the resin and laminates as a result of absorption were also determined for various fibre orientations. These changes were found to be functions of the absorbed moisture content, corrected for leaching, and independent of the temperature of absorption, even when the absorption temperature exceeded the glass transition temperature of the resin. A curve-fitting programme was used to obtain empirical expressions relating the average values of various mechanical properties after immersion at various temperatures to absorbed water content. After extrapolating the kinetic data for absorption to 15°C, these expressions were then used to predict tensile property changes at 15°C over a period of 25 years. Similar methods were also used to predict property changes at 30°C; in this case, experimental confirmation of the predictions was obtained for absorption periods of nearly three years.
Study of External Parasites Infesting Carcharhinus Melanopterus Fish From The Red Sea In Jeddah, Saudi Arabia
Parasitic diseases are harmful and limiting factors in breeding and rearing ornamental fish industry, such as the Monogenea ( Dactylogyrus sp and Erpocotyletiburonis ) and copepod ( Pandarus sinuatus  and Anchistrotostangi ). The copepod and the monogenean are gill parasites found on the shark; CarcharhinusMelanopterus . The primary purpose of this study was to determine the parasitic infections of sharks in red sea in Jeddah. For this purpose, 19 female C. Melanopterus and 14 male C. Melanopterus were first examined for ectoparasites using wet mount under a light microscope. All male sharks had Monogenea and/or copepod in their gill and only 3 females haven’t infections. Then, we aimed to find a combination of copepod and monogenea infection in C. Melanopterus gills. 50% of male and 42% of female were infected by copepod and monogenea. Our findings revealed that the protozoan infections are very common among sharks. Although, no gross pathology was observed among infected shark, but it is likely that in case of any changes in the environment, then parasitic infections could be harmful.