Although its wide utilization in microbial cultures, the one factor-at-a-time method, failed to find the true optimum, this is due to the interaction between optimized parameters which is not taken into account. Therefore, in order to find the true optimum conditions, it is necessary to repeat the one factor-at-a-time method in many sequential experimental runs, which is extremely time-consuming and expensive for many variables. This work is an attempt to enhance bioactive yellow pigment production by Streptomyces thinghirensis based on a statistical design. The yellow pigment demonstrated inhibitory effects against Escherichia coli and Staphylococcus aureus and was characterized by UV-vis spectroscopy which showed lambda maximum of 449. The FTIR and GC-MS analysis showed that the colorings in this type of product are due to the presence of chromo peptides. Furthermore, the GC-MS measurement determined the presence of 4 compounds, as it gave 4 different retention times within this yellow pigment, but with different percentages, except for the compound BHT when the retention time was 17.86 minutes. Starch casein broth (SCB) was selected as an optimized medium for yellow pigment production. The optimization process was first started with one factor at time method, revealing that maltose and casein were the best carbon and nitrogen sources. Response surface methodology based on central composite design was conducted to obtain the optimal combinations of maltose and casein concentrations, pH, and inoculum size for maximum production of yellow pigment. The results showed that casein was the most effective parameter with F-value 393.1 and the model exhibited good fitting with a correlation coefficient of 0.946. Moreover, the actual maximum yellow pigment product 0.80 nm which aggregated with a predicted value 0.835 nm at maltose concentration 8 g/L, casein 5 g/L, KNO3 0.01 g/L, pH 6 and inoculum size 5%.
In this paper, Pentacene based-organic field effect transistors (OFETs) by using different layers (monolayer, bilayer and trilayer) for three different gate insulators (ZrO2, PVA and CYEPL) were studied its current–voltage (I-V) characteristics by using the gradual-channel approximation model. The device exhibits a typical output curve of a field-effect transistor (FET). Source-drain voltage (Vds) was also investigated to study the effects of gate dielectric on electrical performance for OFET. The effect of capacitancesemiconductor in performance OFETs was considered. The values of current and transconductance which calculated using MATLAB simulation. It exhibited a value of current increase with increasing source-drain voltage.
In this paper, Pentacene based-organic field effect transistors (OFETs) by using different layers (monolayer, bilayer and trilayer) for three different gate insulators (ZrO2, PVA and CYEPL) were studied its current–voltage (I-V) characteristics by using the gradual-channel approximation model. The device exhibits a typical output curve of a field-effect transistor (FET). Source-drain voltage (Vds) was also investigated to study the effects of gate dielectric on electrical performance for OFET. The effect of capacitance semiconductor in performance OFETs was considered. The values of current and transconductance which calculated using MATLAB simulation. It exhibited a value of current increase with increasing source-drain voltage.
The purpose of this research is to identify heritage and highlight its value by drawing on its decorative vocabulary and integrating it with the Arabic calligraphy to revive the heritage in a contemporary style, and to create decorative design units inspired by Sadou and Arabic calligraphy and to employ them in the modern fashion designs. The applied descriptive approach has been used in this research, and the research community is made of women in Riyadh area. The tools used in this research were the questionnaire and the observation. The most important results of the research are: the design of decorative units from the integration of Arabic calligraphy and the decorations of the Saduo, and the use of these units in the design of the o
... Show MoreThe effect of Wood Flour addition to the gamma alumina powder used in the preparation of gamma alumina (ɤ-Al2O3) catalyst carrier extrudates on the pore volume and BET surface area physical properties was investigated. Two parameters which are size of wood flour particles and its quantity were studied. The sizes of wood flour particles used are 150 µm, 212 µm and 500 µm and the weight percentage added to the gamma alumina powder during the preparation of the extrudates are (1%, 3%, 5% and 10%). The results showed that the addition of wood flour to the gamma alumina powder in order to get gamma alumina extrudates used as catalyst carrier is one of the successful methods to improve the pore volume
... Show MorePyrolysis of high density polyethylene (HDPE) was carried out in a 750 cm3 stainless steel autoclave reactor, with temperature ranging from 470 to 495° C and reaction times up to 90 minute. The influence of the operating conditions on the component yields was studied. It was found that the optimum cracking condition for HDPE that maximized the oil yield to 70 wt. % was 480°C and 20 minutes. The results show that for higher cracking temperature, and longer reaction times there was higher production of gas and coke. Furthermore, higher temperature increases the aromatics and produce lighter oil with lower viscosity.
Is in this research review of the way minimum absolute deviations values based on linear programming method to estimate the parameters of simple linear regression model and give an overview of this model. We were modeling method deviations of the absolute values proposed using a scale of dispersion and composition of a simple linear regression model based on the proposed measure. Object of the work is to find the capabilities of not affected by abnormal values by using numerical method and at the lowest possible recurrence.
يهدف هذا العمل الى بيان طبيعة العلاقة بين الادارة بالتجوال والتجديد الاستراتيجي ، ومدى تأثير المتغير المستقل في المتغير التابع. تضمنت فقرات الاستبانة بوصفه الأداة الرئيسة لجمع البيانات ثلاث جوانب اساسية، تضمن الاول البيانات الشخصية للمستجيبين، فيما تضمن الجانب الثاني الفقرات الخاصة بمتغير الادارة بالتجوال من خلال خمسة ابعاد، فيما اشتمل الجانب الثالث على فقرات التجديد الاستراتيجي عبر تناول اربعة ابعاد. ي
... Show MoreThis work aims to show the nature of the relationship between management by walking around (the independent variable) and strategic renewal (the dependent variable), as well as it shows the effect of the independent variable on the dependent variable. Questionnaire items were considered the main tool for data collection by three basic aspects. The first involved the personal data of the respondents, while the second included items related to management by walking in five dimensions, and the third is strategic renewal items by addressing four dimensions. The tourism sector, while the community has six Excellent grade hotels was taken into account in this wor
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Abstract
The net profit reported in the annual financial statements of the companies listed in the financial markets, is considered one of the Sources of information relied upon by users of accounting information in making their investment decisions. At the same time be relied upon in calculating the bonus (Incentives) granted to management, therefore the management of companies to manipulate those numbers in order to increase those bonuses associated to earnings, This practices are called earnings management practices. the manipulation in the figures of earnings by management will mislead the users of financial statements who depend on reported earnings in their deci
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