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Search Results: 1 - 10 of 232 matches for " Kadem Meral "
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Enhancement of Photoluminescence Lifetime of ZnO Nanorods Making Use of Thiourea
Erdal S nmez,Kadem Meral
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/957035
Abstract: We have investigated correlation of photoluminescence lifetime between zinc oxide (ZnO) nanorods and thiourea-doped ZnO nanorods (tu: CH4N2S). Aqueous solutions of ZnO nanorods were deposited on glass substrate by using pneumatic spray pyrolysis technique. The as-prepared specimens were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and time-resolved photoluminescence spectroscopy (TRPL). The photoluminescence lifetime of ZnO nanorods and ZnO nanorods containing thiourea was determined as =1.56±0.05 ns (2=0.9) and =2.12±0.03 ns (2=1.0), respectively. The calculated lifetime values of ZnO nanorods revealed that the presence of thiourea in ZnO nanorods resulted in increasing the exciton lifetime. In addition to the optical quality of ZnO nanorods, their exciton lifetime is comparable to the longest lifetimes reported for ZnO nanorods. The structural improvement of ZnO nanorods, containing thiourea, was also elucidated by taking their SEM images which show the thinner and longer ZnO nanorods compared to those without thiourea.
DETERMINATION OF METOPROLOL IN PURE AND PHARMACEUTICAL DOSAGE FORMS BY SPECTROFLUOROMETRY AND HIGH PERFORMANCE LIQUID CHROMATOGRAPHY
BILAL YILMAZ,KADEM MERAL,ALI ASCI,YAVUZ ORNGANER
Chemical Industry and Chemical Engineering Quarterly , 2011,
Abstract: In this study, new and rapid spectrofluorometry and high performance liquid chromatography (HPLC) methods were developed for determination of metoprolol in pure and pharmaceutical dosage forms. The solvent system, wavelength of detection and chromatographic conditions were optimized in order to maximize the sensitivity of both proposed methods. The linearity was established over the concentration range of 50-4000 ng ml-1 for spectrofluorometry and 5.0-300 ng ml-1 for HPLC methods. The intra- and inter-day relative standard deviation (RSD) was less than 4.14 and 3.86% for spectrofluorometry and HPLC, respectively. The limit of quantitation was determined as 30 and 5.0 ng ml-1 for spectrofluorometry and HPLC, respectively. No interference was found from tablet excipients at the selected assay conditions. The methods were applied for the quality control of commercial metoprolol dosage forms to quantify the drug and to check the formulation content uniformity.
Determination of human growth hormone in pure and pharmaceutical dosage form by spectrofluorometry and high performance liquid chromatography
Yilmaz Bilal,Kadioglu Yucel,Meral Kadem,Onganer Yavuz
Chemical Industry and Chemical Engineering Quarterly , 2012, DOI: 10.2298/ciceq111118015y
Abstract: In this study, a new and rapid spectrofluorometry and high performance liquid chromatography (HPLC) methods were developed for determination of human growth hormone in pure and pharmaceutical dosage form. The solvent system, wavelength of detection and chromatographic conditions were optimized in order to maximize the sensitivity of both the proposed methods. The linearity was established over the concentration range of 1.25-50μg mL-1 for spectrofluorometry and 10-75μg mL-1 for HPLC method. The intra- and inter-day relative standard deviation (RSD) was less than 8.46 and 5.98% for spectrofluorometry and HPLC, respectively. Limits of quantitation were determined as 0.075 and 7.5μg mL-1 for spectrofluorometry and HPLC, respectively. No interference was found from tablet excipients at the selected assay conditions. The methods were applied for the quality control of commercial growth hormone dosage form to quantify the drug and to check the formulation content uniformity.
Analytical solutions for the neutron transport using the spectral methods
Abdelouahab Kadem
International Journal of Mathematics and Mathematical Sciences , 2006, DOI: 10.1155/ijmms/2006/16214
Abstract: We present a method for solving the two-dimensional equation of transfer. The method can be extended easily to the general linear transport problem. The used technique allows us to reduce the two-dimensional equation to a system of one-dimensional equations. The idea of using the spectral method for searching for solutions to the multidimensional transport problems leads us to a solution for all values of the independant variables, the proposed method reduces the solution of the multidimensional problems into a set of one-dimensional ones that have well-established deterministic solutions. The procedure is based on the development of the angular flux in truncated series of Chebyshev polynomials which will permit us to transform the two-dimensional problem into a set of one-dimensional problems.
The Approximate Solution of Fractional Fredholm Integrodifferential Equations by Variational Iteration and Homotopy Perturbation Methods
Abdelouahab Kadem,Adem Kilicman
Abstract and Applied Analysis , 2012, DOI: 10.1155/2012/486193
Abstract: Variational iteration method and homotopy perturbation method are used to solve the fractional Fredholm integrodifferential equations with constant coefficients. The obtained results indicate that the method is efficient and also accurate.
Note on the Solution of Transport Equation by Tau Method and Walsh Functions
Abdelouahab Kadem,Adem Kilicman
Abstract and Applied Analysis , 2010, DOI: 10.1155/2010/704168
Abstract: We consider the combined Walsh function for the three-dimensional case. A method for the solution of the neutron transport equation in three-dimensional case by using the Walsh function, Chebyshev polynomials, and the Legendre polynomials are considered. We also present Tau method, and it was proved that it is a good approximate to exact solutions. This method is based on expansion of the angular flux in a truncated series of Walsh function in the angular variable. The main characteristic of this technique is that it reduces the problems to those of solving a system of algebraic equations; thus, it is greatly simplifying the problem. 1. Introduction The Walsh functions have many properties similar to those of the trigonometric functions. For example, they form a complete, total collection of functions with respect to the space of square Lebesgue integrable functions. However, they are simpler in structure to the trigonometric functions because they take only the values 1 and ?1. They may be expressed as linear combinations of the Haar functions [1], so many proofs about the Haar functions carry over to the Walsh system easily. Moreover, the Walsh functions are Haar wavelet packets. For a good account of the properties of the Haar wavelets and other wavelets, see [2]. We use the ordering of the Walsh functions due to Paley [3, 4]. Any function can be expanded as a series of Walsh functions In [5], Fine discovered an important property of the Walsh Fourier series: the th partial sum of the Walsh series of a function is piecewise constant, equal to the mean of , on each subinterval . For this reason, Walsh series in applications are always truncated to terms. In this case, the coefficients of the Walsh (-Fourier) series are given by where is the average value of the function in the th interval of width in the interval , and is the value of the th Walsh function in the th subinterval. The order Walsh matrix, , has elements . Let have a Walsh series with coefficients and its integral from 0 to have a Walsh series with coefficients : . If we truncate to terms and use the obvious vector notation, then integration is performed by matrix multiplication , where and is the unit matrix, is the zero matrix (of order ), see [6]. 2. The Three-Dimensional Spectral Solution In the literature there several works on driving a suitable model for the transport equation in 2 and 3-dimensional case as well as in cylindrical domain, for example, see [7], and by using the eigenvalue error estimates for two-dimensional neutron transport, see [8], by applying the finite element
The Effect of an Instruction Designed by Cognitive Load Theory Principles on 7th Grade Students’ Achievement in Algebra Topics and Cognitive Load  [PDF]
Aygil Takir, Meral Aksu
Creative Education (CE) , 2012, DOI: 10.4236/ce.2012.32037
Abstract: The purpose of this study was to investigate the effect of an instruction designed by the Cognitive Load Theory (CLT) principles on 7th grade students’ achievement in Algebra topics and cognitive load. A quasi-experimental study was conducted in totally six weeks with 80 students. The instruction designed by CLT principles was used in the experimental group, while the instruction recommended by the Ministry of Education (MONE) was used in the control group. Researchers developed Teachers’ Guidelines and Students’ Booklets for using in the experimental group. At the end of each unit, the Subjective Rating Scale (SRS) was used to measure students’ cognitive load. At the end of the treatment, the Algebra Achievement Test (AAT) was administrated to both of the groups. Both descriptive and inferential statistical techniques were used for analyzing data. Results showed that instruction designed by CLT principles was effective for the Algebra teaching with the limitations of the study.
Critical Factors that Affecting Efficiency of Solar Cells  [PDF]
Furkan Dincer, Mehmet Emin Meral
Smart Grid and Renewable Energy (SGRE) , 2010, DOI: 10.4236/sgre.2010.11007
Abstract: A solar cell or photovoltaic cell is a device which generates electricity directly from visible light. However, their efficiency is fairly low. So, the solar cell costs expensive according to other energy resources products. Several factors affect solar cell efficiency. This paper presents the most important factors that affecting efficiency of solar cells. These effects are cell temperature, MPPT (maximum power point tracking) and energy conversion efficiency. The changing of these factors improves solar cell efficiency for more reliable applications.
Deep Venous Thrombosis in Breast Cancer Patients Using Tamoxifen, a Hypothesis  [PDF]
Meral Sayin, Bekir Hakan Bakkal
Journal of Cancer Therapy (JCT) , 2011, DOI: 10.4236/jct.2011.25081
Abstract: Breast cancer is the most frequently diagnosed cancer in women and systematic therapy is an essential component of disease. Hormonal therapy, cytotoxic chemotherapy and the more recently introduced biological therapies are routinely employed in the vast majority of patients. Several pharmaceuticals that affect the estrogenic pathways have been studied as chemopreventive agents. Tamoxifen is an anti-estrogenic drug used in the treatment of estrogen receptor positive breast cancer patients. One of the important side-effects of tamoxifen is thromboembolic events like deep venous thrombosis. Tamoxifen also causes an increase in mean platelet volume. We hypothesize that thromboembolic effect of tamoxifen is via increase of mean platelet volume.
Laboratory Evaluation of Acoustic Backscatter and LISST Methods for Measurements of Suspended Sediments
Ramazan Meral
Sensors , 2008, DOI: 10.3390/s8020979
Abstract: The limitation of traditional sampling method to provide detailed spatial andtemporal profiles of suspended sediment concentration has led to an interest in alternativedevices and methods based on scattering of underwater sound and light . In the presentwork, acoustic backscatter and LISST (the Laser In Situ Scattering Transmissometry)devices, and methodologies were given. Besides a laboratory study was conducted tocompare pumping methods for different sediment radiuses at the same concentration. Theglass spheres (ballotini) of three different radiuses of 115, 137 and 163 μm were used toobtain suspension in the sediment tower at laboratory. A quite good agreement wasobtained between these methods and pumping results with the range at 60.6-94.2% forsediment concentration and 91.3-100% for radius measurements. These results and theother studies show that these methods have potential for research tools for sedimentstudies. In addition further studies are needed to determine the ability of these methods forsediment measurement under different water and sediment material conditions.
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