Solar cells thin films were prepared using polyvinyl alcohol (PVA) as a thin film, with extract of natural pigment from local flower. A concentration of 0.1g/ml of polyvinyl alcohol solution in water was prepared for four samples, with various concentrations of plant pigment (0, 15, 25 and 50) % added to each of the four solutions separately for preparing (PVA with low concentrated dye , PVA with medium concentrated dye and PVA with high concentrated dye ) thin films respectively . Ultraviolet absorption regions were obtained by computerized UV-Visible (CECIL 2700). Optical properties including (absorbance, reflectance, absorption coefficient, energy gap and dielectric constant) via UV- Vis were tested, too. Fourier transform infrared (FTIR) spectrophotometer was employed to test the samples. Thermal analysis of thin films, including melting point (Tm), onset degree, endset degree, and crystallinity% were tested by differential scanning calorimeter (DSC). Three dimensional morphologies of thin films were inspected by atomic force microscopy (ATM). Contact angle also was tested as an index to hydrophilicity. Results proved that the ultraviolet and FTIR absorption increase after adding the natural pigment to PVA thin film, as well as it increases with increasing concentration of natural pigment. DSC analysis revealed an increase of PVA melting point when adding 15% concentration and it decreases with a 50% concentration of pigment. AFM results show an increase in surface roughness, hence the surface bearing index of PVA thin films is inversely proportional to pigment concentration. Contact angle decreases from 46.5° for pure PVA thin film to 44. 8°, 42. 6° and 35.2° after adding (15, 25, and 50)% concentration of natural dye respectively. Optical properties were enhanced by adding the natural dye, hence energy gap decreased from 3 eV for pure PVA to 2.3 eV for the PVA with a high concentrate dye. Dielectric constant increased with increasing concentration of dye, which leads to high polarization of solar cell.
Most studies indicated that the values of atmospheric variables have changed from their general rates due to pollution or global warming etc. Hence, the research indicates the changes of direct solar radiation values over a whole century i.e. from 1900 to 2000 depending on registered data for four cities, namely (Mosul - Baghdad - Rutba - Basra. Moreover, attemptsto correlate the direct solar radiation with the temperature values have been recorded over that period. The results showed that there is a decreasing pattern of radiation quantities over time throughout the study period, where the value of direct radiation over the city of Baghdad 5550 w/m2 was recorded in the year 1900, but this ratio decreased cle
... Show MoreIn the current research, the work concentrated on studying the effect of curvature of solar parabolic trough solar collector on wind loading coefficients and dynamic response of solar collector. The response of collector to the aerodynamic loading was estimated numerically and experimentally. The curvature of most public parabolic trough solar collectors was investigated and compared. The dynamic response of solar collector due to wind loading was investigated by using numerical solution of fluid-structure interaction concept. The experimental work was done to verify the numerical results and shows good agreement with numerical results. The numerical results were obtained by using finite element software package (ANSYS 14). It was found
... Show MoreThe measurement of natural radioactivity in a given region or country is essential to provide a reference base-line map to follow up a possible variation in future. In order to perform such measurement, the natural radioactivity was measured in different locations. The locations (50 sites) were distributed over Al-Jabal Al-Gharbi Mountain, starting from the city Al-Azeeziah in the eastern part to Wazen on the Tunisian border in the west. The measurements showed obvious variation from one site to another. The levels were fluctuating from (12.8 counts/minute) in Bir-Ayad to (45.7 counts/minute) in Gherian.
In order to investigate the cause for such variation, samples were collected from (27) sites for detailed study. The levels of natur
Quantitative real-time Polymerase Chain Reaction (RT-qPCR) has become a valuable molecular technique in biomedical research. The selection of suitable endogenous reference genes is necessary for normalization of target gene expression in RT-qPCR experiments. The aim of this study was to determine the suitability of each 18S rRNA and ACTB as internal control genes for normalization of RT-qPCR data in some human cell lines transfected with small interfering RNA (siRNA). Four cancer cell lines including MCF-7, T47D, MDA-MB-231 and Hela cells along with HEK293 representing an embryonic cell line were depleted of E2F6 using siRNA specific for E2F6 compared to negative control cells, which were transfected with siRNA not specific for any gene. Us
... Show MoreSilver/polyvinyl alcohol (Ag/PVA) nanocomposite films were synthesized via solution casting with varying concentrations of Ag nanoparticles (1–5 wt%). A comprehensive investigation was conducted to understand the influence of Ag content on the structural, optical, mechanical, thermal, electrical, and antibacterial properties of the composites. UV-Vis spectroscopy revealed a red shift in absorption peaks and a reduction in the optical band gap, which decreased from 3.78 eV for pure PVA to 3.37 eV for the 5 wt% Ag composite. FTIR and SEM analyses confirmed successful nanoparticle incorporation and morphological changes. The nanocomposites exhibited enhanced tensile strength, elongation at break, Young’s modulus, and hardness due t
... Show MoreA great deal of attention has recently been given to the use of polyvinyl alcohol and its suitably modified derivatives as aqueous and coating phase corrosion inhibitors because of their polymeric nature, relatively high aqueous phase solubility, and biodegradable properties. The purpose of this study was to investigate the thermal stability and inhibition efficiency of modified polyvinyl alcohol/carboxymethyl cellulose. Gold or silver nanoparticles were used to accomplish this goal. In the current study, polyvinyl alcohol reacted with newly synthesized compounds [I-VI] in DMF to produce modifications of polyvinyl alcohol [VII-XII]. To create [XIII-XVIII], modified polyvinyl alcohol is blended with carboxymethyl cellulose. Then, ble
... Show MoreThe effect of adding different volume of coumarin dye (5, 15, 25 and 35) ml on optical properties of Poly (Methyl Meth Acrylate) was studied. Films of pure PMMA and PMMA with different volume of coumarin dye (5, 15, 25 and 35) ml were prepared using the casting technique. Transmission and absorption of the films were measured by using UV-VIS spectrometer technique type (100 Conc), in order to assess the type of transmission which was found an indirect transition. An optical energy gap of pure PMMA is (4.95e v) and after adding coumarin with volume (25, 35) ml, the energy gap for PMMA decrease by (0.05) compere to pure PMMA films and addition energy gap appear equal to (4.1 e v). It was found that the absorption coefficient, extinction coeff
... Show Moreلم تولد الجماهيرية العالية للسينما من فراغ، إنّما تحققت من إيمان المتلقي العميق، بأن الفيلم أبعد من محاولة للترفيه، فالسينما هي فلسفة العصر، التي تتناول القضايا المهمة لتقدمها عبر حكايتها مؤطّرة بمنطق محدّد ومدفوعة ببناء عاطفي مؤثر، يهيئ المتلقي للاهتمام بهذه القضايا واستيعابها، والتغير المناخي واحد من أهم المواضيع التي بدأت السينما في الحقبة السابقة بتبنيها وتقديمها ضمن بنى حكائية تزيد من وعي المتل
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