Annealing characteristics of amorphous silicon alloy solar cells irradiated with 1.00 MeV protons

Amorphous Si:H and amorphous Si sub x, Ge sub (1-x):H solar cells were irradiated with 1.00 MeV proton fluences in the range of 1.00E14 to 1.25E15 cm (exp -2). Annealing of the short circuit current density was studied at 0, 22, 50, 100, and 150 C. Annealing times ranged from an hour to several days. The measurements confirmed that annealing occurs at 0 C and the initial characteristics of the cells are restored by annealing at 200 C. The rate of annealing does not appear to follow a simple nth order reaction rate model. Calculations of the short-circuit current density using quantum efficiency measurements and the standard AM1.5 global spectrum compare favorably with measured values. It is proposed that the degradation in J sub sc with irradiation is due to carrier recombination through the fraction of D (o) states bounded by the quasi-Fermi energies. The time dependence of the rate of annealing of J sub sc does appear to be consistent with the interpretation that there is a thermally activated dispersive transport mechanism which leads to the passivation of the irradiation induced defects

HEGEMONY IN A GLOBALIZED WORLD: A CRITICAL DISCOURSE ANALYSIS OF THE G8-BROADER MIDDLE EAST AND NORTH AFRICA PARTNERSHIP FROM 2004-2013

This study addresses current educational, political, and social challenges that many marginalized countries face, especially nations in the Broader Middle East and North Africa (BMENA) region. The study examines the types of hegemony and its effects by addressing political, social, and educational ramifications. It scrutinizes the political, educational, and social history of the Kingdom of Saudi Arabia and uses it as an example for the region because of its political influence on the region. The study engages in a critical analysis of globalization alongside its tools to highlight its advantages and disadvantages to marginalized countries. It discusses the spread of the English language in marginalized communities, together with the status of the Arabic language in both lexical and mental dimensions. Critical Discourse Analysis (CDA) was the methodology used to analyze the G8-Broader Middle East and North Africa G8-BMENA Partnership through examining documents produced by two entities in their annual meetings: first, government officials, and second, representatives of civil societies. These documents are organized by the type of discourse: first, official discourse (dominant) by government representatives, and second, public discourse by civil societies. The idea is to examine the connections and disconnections between the two discourses in the proposed reform efforts by the partnership. The study analyzes documents issued from 2004 to 2013, and it reveals evidence of a hegemonic relationship between the G8 countries, BMENA countries, and civil societies. It also uncovers some possible and dangerous political changes affecting not only the BMENA but also the world

Annealing characteristics of irradiated hydrogenated amorphous silicon solar cells

It was shown that 1 MeV proton irradiation with fluences of 1.25E14 and 1.25E15/sq cm reduces the normalized I(sub SC) of a-Si:H solar cell. Solar cells recently fabricated showed superior radiation tolerance compared with cells fabricated four years ago; the improvement is probably due to the fact that the new cells are thinner and fabricated from improved materials. Room temperature annealing was observed for the first time in both new and old cells. New cells anneal at a faster rate than old cells for the same fluence. From the annealing work it is apparent that there are at least two types of defects and/or annealing mechanisms. One cell had improved I-V characteristics following irradiation as compared to the virgin cell. The work shows that the photothermal deflection spectroscopy (PDS) and annealing measurements may be used to predict the qualitative behavior of a-Si:H solar cells. It was anticipated that the modeling work will quantitatively link thin film measurements with solar cell properties. Quantitative predictions of the operation of a-Si:H solar cells in a space environment will require a knowledge of the defect creation mechanisms, defect structures, role of defects on degradation, and defect passivation and annealing mechanisms. The engineering data and knowledge base for justifying space flight testing of a-Si:H alloy based solar cells is being developed

Measuring the Service Delivery Quality Mobily Telecom in the Western Region of Saudi Arabia as a Case Study

The objective of this research was to measure thequality of service delivery of the telephone service in MobilyTelecom in the western region of Suadi Arabia so as to detectthe gap type (positive or negative) and determine, if there, thematch between customers’ expectations and employees’perception. To do just this, SERVQUAL model was used.Concerning the sample of the study, Mobily Telecom in thewestern Region (Mecca and Jeddah) was selected. In detail, thesample of company officials was 164 employees and 221customers (both current and potential). The research adoptedthe survey as a tool to collect data. As for results, the researchhas come out with tangible findings, including the following:there is a negative gap between customers’ expectations andofficial’s awareness in terms of the dimensions of service qualityof service and there is a negative gap between customers’perception towards service quality elements and management’sawareness to those elements

Structural Characterization and Mechanical Behavior of Al 6061 Nanostructured Matrix Reinforced with TiO2 Nanoparticles for Automotive Applications

The main aims of the present chapter are to: learn synthesis procedure of AA 6061‐x wt.% TiO2 nanocomposites (x = 0, 2, 4, 6, 8, 10 and 12 wt.%) by mechanical alloying (MA); investigate structural characterization of manufactured nanocomposite powders using X‐ray line profile analysis, scanning electron microscope (SEM) and transmission electron microscope (TEM); examine consolidation method and mechanical behavior in terms of sintered density, Vickers hardness and compressive stress‐strain behavior; study the improvement of ductility in nanocomposites; and simulate the mechanical behavior using ANSYS. Here, the synthesized nanocomposites via MA were consolidated using conventional uniaxial die compaction; then, the green compacts were sintered at different temperatures. TEM microstructures of as‐milled powder samples showed the matrix crystallite sizes ranging from 45 to 75 nm, which depended on the amount of reinforcement. A remarkable decrease in matrix powder particles size with the function of reinforcement was observed due to the ceramic nano TiO2 particles acted as milling agent. The sintered nanocomposites yielded maximum strength of 1.126 GPa. The study of trimodeled composite and its mechanical behavior revealed the possibility of achieving improvements in ductility and toughness for nanocomposites. The simulated mechanical behavior results using finite element method were good agreement with experimental results

An Evaluation of ICT Integration in Science Learning in Primary Schools in Saudi Arabia

Technology plays an important role in education, and Saudi Arabia has dedicated a huge budget to develop technology for education. The aim of this mixed-methods study is to evaluate ICT integration in science education in upper primary schools by investigating both students’ and teachers’ perceptions of ICT use. Participants perceived the ICT integration positively but faced several challenges including time and technical issues. Many participants suggested providing devices to improve Saudi science education

Magnetic studies on superconducting oxides

In the first part of this Thesis the structural and superconducting properties of some Yttrium-Barium-Copper-Oxides (YBCO) superconducting materials have been examined. These materials, which were discovered only about three years ago, have the important property that they become superconducting at temperatures below about 86K. Because this transition temperature (T(_c)) is well above the temperature (77K) of liquid nitrogen- a readily available refrigerant- there is very considerable interest in potential technological applications. The nominal composition of YBCO material is YBa(_2)Cu(_3)O(_7) and for superconductivity the value of x must be near 7-x = 7.0. X-ray diffraction methods have been used to determine the lattice parameters and values of x for a range of oxides prepared from different starting materials by different routes. These structural studies were extended by Scanning Electron Microscopy which gave information about the grain size and microstructure of the materials. A major part of the work considered the development of an inductance probe technique for examining the superconducting properties. This technique was based on the Meissner effect and involved measuring the inductance of a small coil which was filled with superconducting material as a function of temperature and magnetic field. From these measurements several superconducting properties have been determined. These included the transition temperature (T(_c)), the percentage of superconducting material present in a given sample, the first critical field (H(_c1), and hysteresis. The critical field is the value at which an external magnetic field penetrates into the superconductor to a depth known as penetration depth (A) which corresponds to a non-superconducting layer. The values of H(_c1) were all found to be about 15 gauss, rather smaller than those previously reported in the Uterature. The variation of A with temperature was also examined and shown to be in excellent agreement with theory based on a Type II model. In an attempt to correlate these superconducting properties with the structural studies it was shown that the most promising superconductors were those in which the grain size was relatively large (greater than lOpm) and in which the grains were closely packed together. In the second part of the Thesis some non-superconducting oxides were examined by magnetic resonance methods. In the first group of experiments the epr linewidths of the M= + l/2 ↔ -1/2 transition of the Cr(^3+) spectrum of Cr/MgO single crystals and powders have been measured at 9GHz before and after annealing. The nominal chromium concentrations ranged from 800 to 15,000 ppm. Specimens were annealed at 500 C in oxygen for up to 150 hours. Annealing produced reductions in peak-to-peak linewidth (∆H(_pp)) which occurred in two stages. Each followed an exponential [∆ H pp] (_t) = [∆ H pp] (_0)exp(^-at)and the initial (a(_1)) and final (a(_2_) decay rates were determined from the slopes of Ln[∆ H pp] (_t) versus time plots. For single crystals all the values of a(_1) were about 0.04 h(^-l); the smaller values of a(_2) were concentration dependent ranging from 0.9 x 10(^-3) to 1.25 X lO(^-3)h(^-1) for the two sources of strain. The rapid decay rate is associated with cationic vacancy strain relief and the slower decay with removal of lattice distortion brought about when the Mg(^2+) ions are replaced by Cr(^3+) dopant ions. Similar effects were observed with powders but in these both types of lattice strain were relieved at a slower rate in the powder than in the corresponding single crystal, e.g. for 3600 ppm Cr, a(_1) = 0.016h(^-1) and a(_2) = 1.0 x 10(^-3)h(^-1) In the second group of experiments the mechanisms of magnesiochromite formation were studied and the effect of this on epr linewidth was examined. The results of both groups of experiments were related to the more general problem of the dipolar mechanisms responsible for the variation of epr linewidth with concentration in the Cr/MgO system

Exploring young Saudi women's engagement with social media : feminine identities, culture and national image

PhD ThesisWith the rising popularity of social media in the last decade and a half, young women in Saudi Arabia have been utilising these platforms to negotiate values and norms in relation to issues such as veiling, work, their place within the private sphere, and their relationships with the opposite-sex. The aim of this thesis is to understand how the rise of social media engagement is impacting long-held traditions and values about Saudi women, and how their social media use is impacting on their public national image. The research addresses the interplay between Saudi conservative nationalists, who wish to preserve a traditional image of femininity that is highly tied to notions of piety and deference, and the Saudi women who, through social media, are actively challenging these longstanding views on how women should behave in society. Drawing on Nancy Fraser’s notion of counterpublics (Fraser 1991), this research argues that the democratic potential of social media platforms, independent of cultural and state laws that serve to direct, control and determine the attitudes and behaviour of young Saudi women, has facilitated the emergence of a counterpublic in which alternate contemporary identities are expressed and represented. By employing a triangulation approach for collecting data within a constructivist research paradigm, this research draws on four sets of data. Firstly, it uses netnography to observe the public accounts of seven female social media influencers. Secondly, it observes the personal accounts of nine Saudi women. A third set of data consists of six one-to-one interviews. Finally, a fourth set of data entails seven focus groups involving an overall sample of 36 participants. Using thematic analysis, this research argues that Saudi women, particularly younger women, using social media are adopting a more critical view of traditional customs surrounding femininity and women’s place in a society constructed through a collectivist ideology towards more individualistic values, norms and social ties that emphasise agency and autonomy (Giddens, 1991). I also argue that Saudi women active on social media are modernising the national public image of Saudi women. By engaging with Dobson’s (2015) study of post-feminist digital culture, I explore the contemporary ideals of Saudi femininity that are portrayed on social media by the young Saudi women I observe in this research and I document the complex and many ways these women can now be in the world. I find that women’s engagement with social media is challenging traditional values and norms and performing a vanguard role in reimagining the public national image of Saudi women today