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August 2020
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Transparent level temperature dependence of semiconductor lasers
Safwat William Zaki Mahmound, Abanoub Mikhail
Abstract: The point at which a material stops being absorptive is called transparency. Gain in the active medium of a laser device cannot occur unless the carrier concentration exceeds the transparency density. If the semiconductor is further pumped beyond transparency by optical or electrical means, the gain becomes equal to the total loss and the material starts to lase at the threshold level. Joule heating, free carrier absorption, and band filling effects change the refractive index of the semiconductor and hence the lasing wavelength. The change of the refractive index with temperature is referred to as the thermo-optic effect. This work presents a semi-classical numerical model to investigate the temperature dependence of the carrier concentration, operating voltage, and refractive index at transparency level for GaAs, In0.15Ga0.85As, and In0.48Ga0.58As0.9P0.1 over the temperature range from oK to oK. Results revealed that the transparency lasing wavelength fit with temperature obeys a rational equation. In addition, the refractive index change due to band filling is calculated at transparency over the studied temperature range and modeled as third order polynomial in temperature. The study concludes that there is a material-dependent temperature at which the band to band transition contribution to the refractive index is minimum and found to be oK, oK, and oK for GaAs, In0.15Ga0.85As, and In0.58Ga0.42As0.9P0.1 in order. The refractive index change due to free carriers was found to be more sensitive to temperature variation than the refractive index change due to band to band transition.
[ FULL TEXT PDF 1-8 ] DOI: 10.22587/ajbas.2020.14.8.1
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Photochemical Investigation of Flowers and Leaves of Cucurbita Maxima (Pumpkin)
Vishal Mahabir
Abstract: There are a number of nutrient metals that are essential to keeping the body healthy. Many of these nutrients are found naturally in organic vegetables and other cereals. Pumpkin is a very common vegetable available mostly throughout the year all over the world. Different parts of pumpkin have different amounts of these metals. Earlier study of the skin, flesh and seed of pumpkin has shown that K, Ca, Mg, P, Zn, Cu, Ni, Fe, Co; and heavy metals, Pb and Cd are present in different amounts (Mahabir and Verma, 2012). These elements were also found in various quantities in pumpkin leave and flower. The present photochemical study focuses on the flowers and leaves of pumpkin because in many countries people make use of the flowers and soft leaves of pumpkin as a vegetable. The samples collected for this paper originated from three different plants directly from a vegetable farm. The samples were digested by aqua regia method. The flame atomic absorption spectroscopic method was then used to investigate the presence of nutrient elements for each digested sample. Manganese (0.35 ppm), zinc (1.55 ppm), nickel (46.83 ppm), cobalt (14.67 ppm), iron (1.55 ppm), copper (0.52 ppm), magnesium (35.40 ppm) and potassium (425.60 ppm) were found in the leaves. In addition, manganese (0.00 ppm), nickel (104.78 ppm), cobalt (61.64 ppm), iron (0.55 ppm), copper (0.12 ppm), magnesium (22.5 ppm) and potassium (166.40 ppm) were found in the flowers. The hypothesis of this paper is that the degree of naturally occurring zinc and other metals in pumpkin’s leaves and flowers is significant enough to warrant special attention as a nutritional inhibitor of prostate cancer and other illnesses, respectively (Franz, 2013).
[ FULL TEXT PDF 9-14 ] DOI: 10.22587/ajbas.2020.14.8.2
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An HCI-Based Shadow Teacher Application for Autistic Children in Egypt: Review Paper
Hania El-Shoubashy, Prof. Saleh Mesbah, Prof. Hatem Abdel-Kader
Abstract: Autistic children’s education is a complex process that requires robust professional support. The success of their teaching and learning is impeded by their mental and social impairment. Paraprofessional assistance has raised skeptic concerns regarding the quality of their ambiguous qualification and training in relation to the expected outcomes. Previous studies revealed that autistic children represents 3% of all special needs young patients, however, no accurate Egyptian records can actually define the true prevalence of autistic children. This could be attributed to the lack of sharp clinical presentations carrying a clear differentiation, peculiar to this mental disability, which prevents reaching an accurate diagnosis leading to a clear allocation to their specific autism group. The emergence of the mobile technology strongly impacted the daily life and the communication pattern of people worldwide with specific emphasis on the business world.
[ FULL TEXT PDF 15-28 ] DOI: 10.22587/ajbas.2020.14.8.3
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What is Gamification? Literature Review of Previous Studies on Gamification
Hend El Shoubashy, Prof. Hatem Abd El Kader, Dr. Nermine Khalifa
Abstract: The present work is a literature review on the gamification framework in the business world. Gamification has recently gained popularity in the last decades. Controversies regarding its definition in published work, fostered the reviewing research curious interest. The defined reached consensus was in favor of considering gamification as the use of gamified design elements in non-gaming context for enhancing customer engagement. The success of a framework mandates the application of an appropriate design, however, throughout the literature reviewed, through a visited number of gamification-based solutions failed. This was interpreted on the fact that it was created based on a crowded design of mixed game elements components without a formal clear design process. A consensus was thus reached, that it is of utmost importance to identify the needs, characteristics and synthetize the methods and process of the gamification framework design to achieve the required engagement experience. this review categorized the existing reported approaches with assessment of their main features, fallacies and difficulties in a trial to support developers of gamified solutions recognize, distinguish and select the best approaches to properly understand the principles and reach solutions at different levels and scope of gamification
[ FULL TEXT PDF 29-51 ] DOI: 10.22587/ajbas.2020.14.8.4
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