Fabrication, Electrical Characterization and Simulation of Thin Film Solar Cells: CdTe and CIGS Materials

CdTe and Cu(In,Ga)Se2 (CIGS) thin film solar cells are fabricated, electrically characterized and modelled in this thesis. We start from the fabrication of CdTe thin film devices where the R.F. magnetron sputtering system is used to deposit the CdS/CdTe based solar cells. The chlorine post-growth treatment is modified in order to uniformly cover the cell surface and reduce the probability of pinholes and shunting pathways creation which, in turn, reduces the series resistance. The deionized water etching is proposed, for the first time, as the simplest solution to optimize the effect of shunt resistance, stability and metal-semiconductor inter-diffusion at the back contact. In continue, oxygen incorporation is proposed while CdTe layer deposition. This technique has been rarely examined through R.F sputtering deposition of such devices. The above experiments are characterized electrically and optically by current-voltage characterization, scanning electron microscopy, x-ray diffraction and optical spectroscopy. Furthermore, for the first time, the degradation rate of CdTe devices over time is numerically simulated through AMPS and SCAPS simulators. It is proposed that the instability of electrical parameters is coupled with the material properties and external stresses (bias, temperature and illumination). Then, CIGS materials are simulated and characterized by several techniques such as surface photovoltage spectroscopy is used (as a novel idea) to extract the band gap of graded band gap CIGS layers, surface or bulk defect states. The surface roughness is scanned by atomic force microscopy on nanometre scale to obtain the surface topography of the film. The modified equivalent circuits are proposed and the band gap graded profiles are simulated by AMPS simulator and several graded profiles are examined in order to optimize their thickness, grading strength and electrical parameters. Furthermore, the transport mechanisms and Auger generation phenomenon are modelled in CIGS devices

Using of GGE biplot in determination of genetic structure and heterotic groups in wheat (Triticum aestivum L.)

The present study was undertaken to analyze diallel data using GGE biplot model to gather information about genetic interrelationships among parents and identification of heterotic combinations for yield and yield components in bread wheat varieties. For this purpose, 8 bread wheat genotypes tested across in half-diallel crosses design, GGE biplot technique was used. Parents included the genotypes of Kouhdasht, Karim, Ehsan, Mehregan, N-92-9, Line 17, N80-19 and Atrak. The hybrids obtained from the one-way cross (28 hybrids) in agricultural years of 2016-17 were evaluated as randomized complete block design in two replications on the research farm of Gonbad Kavous University. The evaluated traits included the grain yield, weight of spike grains, number of grains in spike and number of spikes. Additive main effects and genotype × environment interaction (GGE) were employed in the evaluation of genotypes; analyses showed significant (P< 0.01) G × E, (genotype × environment interaction) with respect to plant seed yield. GGE biplot analysis showed that Karim was as the best general combiners for grain yield, number grain per spike and grain weight per spike, whereas Ehsan had the highest GCA effects for number of spikes. Ehsan and Karim had higher specific combining ability than other genotypes. The studied genotypes for this trait were divided into two heterotic groups where the first group included the genotypes of Kouhdasht, N-92-9, N80-19 and Atrak and the second group contained the genotypes of Line 17, Mehregan and Karim. Mehregan line had a weak combining ability with all testers and N-92-9 had also more power than others. Based on the biplot, the Karim genotype with high general adaptation was introduced as the ideal genotype in terms of grain yield, spike number, grain number per spike and grain weight, so the Karim genotype can be adapted to obtain high yield hybrids

Determination of Heavy Metals through Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) in Iranian Cheese and Their Potential Health Risks to the Adult Consumers

In Iran, cheese is one of the dairy products that widely consumed as a main diet for breakfast. Moreover, trace metals in dairy products have recently gained considerable attention. Iranian cheese samples were collected from Tehran, Iran (February to May 2013). Trace metals including Pb, Cd, Ni, Fe, Sn, Zn, Cr, and Cu were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES) after dry ashing. All the tested metals were detected in the cheese samples. The mean concentration of metals in cheese showed the following decreasing order Zn > Fe > Cu > Ni > Sn > Cr > Pb > Cd, with values of 12.98, 7.95, 1.96, 0.83, 0.46, 0.37, 0.34, and 0.01 mg/kg, respectively. There were no significant differences between types of cheese samples in terms of content of trace metals (p>0.05). All the samples had Pb contents of greater than Codex limit (0.02 mg/kg). According to the measured values of the metals in this study, the intake of all the studied elements through the common consumption of cheese in Iran was below the dangerous level according to permissible intake value for each metal. Also, levels of correlations between the element pairs were analyzed

Audit of the Standard Precautions Formulated against the Transmission of Bloodborne Diseases in the Hemodialysis Wards of the Hospital Affiliated to Shahrekord University of Medical Sciences (2014)

Background & Objective: Hemodialysis ward personnel are at a higher risk of contact with blood and body fluids and sharp objects due to the conditions of these wards and frequent contact with hemodialysis patients. The present study aimed to audit the standard precautions in the hemodialysis wards of the hospitals affiliated to Shahrekord University of Medical Sciences, Iran. Materials and Methods: This descriptive-analytical study was conducted on 60 nurses in the hemodialysis wards of the hospital affiliated to Shahrekord University of Medical Sciences, who were selected via census sampling. Data were collected using a researcher-made demographic questionnaire and standard precautionary checklist. Data analysis was performed in SPSS version 12 using frequency tables, mean, standard deviation, t-test, one-way ANOVA, and Pearson's correlation-coefficient. Results: The standard precautions against the transmission of bloodborne diseases were not at a poor level in any of the hemodialysis wards of the hospitals affiliated to Shahrekord University of Medical Sciences. In addition, the highest observance of the standard precautions was observed in the hemodialysis staff of Lordegan Shohada Hospital. Conclusion: The standard precautions against the transmission of bloodborne diseases were assessed in the hemodialysis wards of the hospitals affiliated to Shahrekord University of Medical Sciences, and these principles were observed to be on moderate and favorable levels. Keywords: Auditing, Formulated Standards, Bloodborne Diseases, Hemodialysi

Postoperative Blepharoptosis After Modern Phacoemulsification Procedure

Purpose: To investigate the frequency of transient (1 month) and persistent (at least 6 months) postoperative ptosis following clear corneal sutureless phacoemulsification and to analyze the factors affecting them. Design: Cohort study. Methods: Patients who underwent phacoemulsification cataract surgery from October 2016 to June 2018 in a tertiary center were enrolled. Margin reflex distance 1 (MRD1), MRD2, and levator function were measured and facial photography was taken before, 1 month, and at least 6 months after the surgery. Clinical ptosis was defined as any postoperative drop of MRD1 and clinically significant ptosis as MRD1 drop of �2 mm. Photo-based ptosis was assessed by a masked oculofacial plastic surgeon at the end of the study. Results: A total of 234 patients (313 eyelids) were included. The majority of surgeries were performed by senior residents (65.5, 205/313) and under topical anesthesia (78.0, 244/313). Persistent clinical, clinically significant, and photo-based ptosis were 25.4 (71/279), 3.2 (9/279), and 3.3 (9/276). Eyelids with persistent postoperative ptosis showed a significantly (P = .03) lower preoperative levator function (13.9 vs 15.8 mm). No other factor was significantly different between the eyelids with and without postoperative ptosis. Conclusion: Persistent clinically significant ptosis was observed in more than 3 of patients undergoing clear corneal sutureless phacoemulsification cataract surgery. It should be counseled preoperatively. Lower preoperative levator function was significantly associated with a higher frequency of postoperative ptosis. Duration of surgery, level of surgeons, and other variables did not have any significant effect on the frequency of postoperative ptosis. © 2020 Elsevier Inc