A metal-assisted chemical etching process employing p-type silicon wafers with varied etching durations is used to produce silicon nanowires. Silver nanoparticles prepared by chemical deposition are utilized as a catalyst in the formation of silicon nanowires. Images from field emission scanning electron microscopy confirmed that the diameter of SiNWs grows when the etching duration is increased. The photoelectrochemical cell's characteristics were investigated using p-type silicon nanowires as working electrodes. Linear sweep voltammetry (J-V) measurements on p-SiNWs confirmed that photocurrent density rose from 0.20 mA cm-2 to 0.92 mA cm-2 as the etching duration of prepared SiNWs increased from 15 to 30 min. The conversion efficiency (ƞ) was 0.47 for p-SiNWs prepared with a 15-minute etching time and 0.75 for p-SiNWs prepared with a 30-minute etching time. The cyclic voltammetry (CV) experiments performed at various scan rates validated the faradic behavior of p-SiNWS prepared for 15 and 30 min of etching. Because of the slow ion diffusion and the increased scanning rate, the capacitance decreased with increasing scanning rate. Mott-Schottky (M-S) investigation showed a significant carriers concentration of 3.66×1020 cm-3. According to the results of electrochemical impedance spectroscopy (EIS), the SiNWs photocathode prepared by etching for 30 min had a charge transfer resistance of 25.27 Ω, which is low enough to enhance interfacial charge transfer.
In this paper, the homotopy perturbation method (HPM) is presented for treating a linear system of second-kind mixed Volterra-Fredholm integral equations. The method is based on constructing the series whose summation is the solution of the considered system. Convergence of constructed series is discussed and its proof is given; also, the error estimation is obtained. Algorithm is suggested and applied on several examples and the results are computed by using MATLAB (R2015a). To show the accuracy of the results and the effectiveness of the method, the approximate solutions of some examples are compared with the exact solution by computing the absolute errors.
Abstract
Characterized by the Ordinary Least Squares (OLS) on Maximum Likelihood for the greatest possible way that the exact moments are known , which means that it can be found, while the other method they are unknown, but approximations to their biases correct to 0(n-1) can be obtained by standard methods. In our research expressions for approximations to the biases of the ML estimators (the regression coefficients and scale parameter) for linear (type 1) Extreme Value Regression Model for Largest Values are presented by using the advanced approach depends on finding the first derivative, second and third.
Electro-chemical Machining is significant process to remove metal with using anodic dissolution. Electro-chemical machining use to removed metal workpiece from (7025) aluminum alloy using Potassium chloride (KCl) solution .The tool used was made from copper. In this present the optimize processes input parameter use are( current, gap and electrolyte concentration) and surface roughness (Ra) as output .The experiments on electro-chemical machining with use current (30, 50, 70)A, gap (1.00, 1.25, 1.50) mm and electrolyte concentration (100, 200, 300) (g/L). The method (ANOVA) was used to limited the large influence factors affected on surface roughness and found the current was the large influence f
... Show MoreIn this paper, the density of state (DOS) at Fe metal contact to Titanium dioxide semiconductor (TiO2) has been studied and investigated using quantum consideration approaches. The study and calculations of (DOS) depended on the orientation and driving energies. was a function of TiO2 and Fe materials' refractive index and dielectric constant. Attention has focused on the effect of on the characteristic of (DOS), which increased with the increasing of refractive index and dielectric constant of Fe metal and vice versa. The results of (DOS) and its relation with and values of system have been discussed. As for contact system is increased, (DOS) values increased at first, but the relation is disturbed later and transforms into an inve
... Show MoreIn this research, Zinc oxide (ZnO)/epoxy nanocomposite was synthesized by simple casting method with 2wt. % ZnO concentration. The aim of this work was to study the effect of pH and composite dosage on the photocatalytic activity of ZnO/ epoxy nanocomposite. Scanning electron microscopy (SEM) technique images proof the homogeneous distribution of ZnO nanoparticles in epoxy. A synthesized nanocomposite samples were characterized by Fourier Transform Infrared spectrometer (FTIR) measurements. Two spectra for epoxy and 2wt.% ZnO/epoxy nanocomposites were similar and there are no new bonds formed from the incorporation of ZnO nanoparticles. Using HCl and NaOH were added to Methylene blue (MB) dye (5ppm) to gat pH values 3 and 8. The degradat
... Show MoreAbstract
The current research aims to construct a scale for the nine types of students’ personality according to Rob Fitzel model. To do this, (162) items were formed that present the nine types of personality with (18) items for each type. To test the validity of the scale, a sample of (584) students of Al-Mustansrya University were chosen. The data of their responses was analyzed by using factor analysis. The findings explored (9) factors as one factor for each type of personality with (12) items for each one. Then, the reliability of the scale was found by using the test-retest method and Alfa Cronbach method.
ABSTRACT
The multi-drug resistant efflux pump is a glycoprotein pump whose function is to push foreign substances. The efflux pump is found in humans, animals. It also has wide-ranging properties in bacteria and fungi. They are found in all species of bacteria, and efflux pump genes can be found in bacterial chromosomes or mobile genetic elements, such as plasmids. The most sensitive function that leads to a global problem is its resistance to antibiotics in bacterial cells, which increases the ability to bacteria from becoming strong virulence factors that most or all antibiotics cannot kill. It also has othe
... Show More
The research aims to identify the most important areas of voluntary work available to women in society, stand on the most important controls that push women to work in voluntary areas in society. The research also seeks to stand on the most prominent obstacles to the voluntary work of women in society. The research contained four main chapters: Chapter I: Definition of research, Chapter 2: Objectives, areas, controls and effects of volunteer work, Chapter 3: Voluntary Work of Women in the Celestial Religions, and lastly, Chapter 4: Theories, Constraints, and Recommendations for Voluntary Work for Women.The researcher suggested several recommendations: 1-establishing a unit responsible for planning,
... Show MoreThe State company for vegetable oils industry one of the most dynamic
companies in the Iraqi economy and is one of the companies manufacturing(food) that takes astrategic dimension and production within the concept of food security, this as well as to reduce dependence on imports and operation of national manpower.This study aims to describe the performance of the State company for vegetable oils industry for the period (2003-2007) which was characterized by economic and security instability of the country and give an accurate picture of their efficiency and their capacity to produce during this Period.
Increasing interest in planning at the level of government units as a means to manage the physical and human resources, direct and invest in areas that would include an increase in the economies of the general government units that are part of the general economics of the state.The research problem lies in the introduction of the factors influencing the ongoing expenses that adversely affect the financial planning process at the level of the Ministry of Health Planning, which affects the quality of services provided to citizens, so I sought the researchers to study the reality of financial planning in some of the Ministry of Health and health departments through the analysis of current budgets and diagnose deviations in the implementatio
... Show More