328 research outputs found

    Saudi Arabia – 2005

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    A Systemic Approach for Evaluating Stakeholder Collaboration within Requirement Collection

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    The involvement of Stakeholders in requirement collection of software projects is essential, and that is evident in the diverse methodologies available that emphasise stakeholder collaboration. However these processes scarcely provide further understanding of the social interaction, and its effect into forming collaboration had not been sufficiently addressed by software development research. It is challenging to identify dominating factors that affect collaboration due to the complexity of stakeholder interaction. This thesis addresses such a challenge. It discusses a systems approach to the evaluation of stakeholder collaboration within requirement collection of software projects. A generic approach has been developed to contribute to our understanding of the problem and support stakeholders’ collaborative involvement. Based on understanding the nature of collaboration between stakeholders in requirement collection, and the concept of perception and its contribution into forming collaboration, the EStaC (Evaluation of Stakeholder Collaboration) approach is developed. EStaC is presented here to describe an integration of multi-methodologies that supports capturing stakeholders' perspectives, and therefore systemically it captures the essence of collaboration within its context. EStaC contributes to the crucial phase of requirement collection with the ultimate objective of extending it to include means of improvement of stakeholder collaboration. It promotes the development of two modes of analysis, the design and diagnosis, which both involves using the principles of the Viable System Model. The novelty of this work is specifically considered with the development of the EStaC approach because unlike other approaches, it focuses on the social act of interaction from a stakeholders viewpoint, by applying systemic strategies and cybernetic driven principles with concepts of fourth generation evaluation. The research recognises evaluation of stakeholder collaboration as an important aspect in the requirement collection process in any software development. It concludes and supports the incorporation of such activities throughout various phases of requirement collection

    Spectrophotometric determination of nicradipine and isradipine in pharmaceutical formulations

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    A sensitive spectrophotometric method was developed for the determination of some 1,4-dihydropyridine compounds namely, nicardipine and isradipine either in pure form or in pharmaceutical preparations. The method is based on the reduction of nicardipine and isradipine with zinc powder and calcium chloride followed by further reduction with sodium pentacyanoaminoferrate (II) to give violet and red products having the absorbance maximum at 546 and 539 nm with nicardipine and isradipine, respectively. Beer’s law was obeyed over the concentration range 8.0–180 μg/ml with the detection limit of 1.67 μg/ml for nicardipine and 8.0–110 μg/ml with the detection limit of 1.748 μg/ml for isradipine. The analytical parameters and their effects on the reported methods were investigated. The molar absorptivity, quantization limit, standard deviation of intercept (Sa), standard deviation of slope (Sb) and standard deviation of the residuals (Sy/x) were calculated. The composition of the result compounds were found 1:1 for nicardipine and 1:2 for isradipine by Job’s method and the conditional stability constant (Kf) and the free energy changes (ΔG) were calculated for compounds formed. The proposed method was applied successfully for the determination of nicardipine and isradipine in their dosage forms. The results obtained were in good agreement with those obtained using the reference or official methods. A proposal of the reaction pathway was presented

    High-performance liquid chromatographic method for the determination of nicardipine in pure, pharmaceutical preparations and plasma and its application to pharmacokinetics in humans

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    A simple, sensitive and reproducible reversed-phase liquid chromatographic method has been developed and validated for the determination of nicardipine hydrochloride (NC) in pure, pharmaceutical preparations, human plasma and the study of the pharmacokinetics of the drug in human body. Nicardipine in plasma were extracted with hexane-butanol (12:1,v/v) after addition of borate buffer (0.5 M, pH=9.0), and then measured by HPLC-UV using a Waters Symmetry C18 column as stationary phase and methanol– triethylamine buffer (0.01M) pH 4 with acetic acid (70:30) as mobile phase. Nicardipine was quantified by ultraviolet absorbance at 353 nm. The method proved to be linear in the pure drug in the ranges of 15-200 ng/mL (r=0.9989) and 5-40 µg/mL (r=0.9995), and for the pharmaceutical preparations and plasma for drug concentrations in the range of 5-40 µg/mL (r =0.9992) and 25-150 ng/mL (r=0.9991), respectively. The lower limit of detection and the lower quantitation limit of NC in plasma were 11.74 and 35.57 ng/mL, respectively. The method is sensitive and reliable for pharmacokinetic studies of nicardipine in humans after the oral administration of immediate-release capsules to healthy subjects

    Dissolution of Gypseous Rocks under Different Circumstances

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    The influence of temperature, flow velocity, gypsum content, salinity of solvent and hole diameter on the amount and rate of dissolution of gypseous rock samples was investigated. The rock samples were obtained from the proposed Al-Fat’ha dam site located approximately 280km to the north of Baghdad city. The gypsum content for these samples ranged from 16% to 90%. Dissolution tests were carried out with the aid of a special system that was modified and manufactured to allow passing water at different speeds through a drilled hole along the center of the rock samples. The amount of dissolution of gypsum was determined under different conditions. The results showed that the amount and rate of gypsum dissolution increased with increasing the temperature of the test. The effect was more pronounced on rock samples with low gypsum content. Increasing the flow velocity also increases the amount and rate of gypsum dissolution. With this parameter, the effect of gypsum content was marginal. Increasing the salinity of the solvent (using low percentages of NaCl additives) has a great influence on the amount and rate of gypsum dissolution, and further increase in the salinity exhibited a marginal increase in the amount of dissolution when compared with the lower salinity concentration. The Tigris river water (as a natural solvent) exhibited a negligible effect on the amount and rate of gypsum dissolution. Increasing the diameter of the hole along the center of the sample increases the inside area exposed to water and hence generates more dissolution

    Comparative Study of Load Carrying Capacity of Steel Tube Columns Filled with Lightweight Concrete and Normal Concrete

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    Tests on steel columns filled with normal concrete and lightweight concrete were carried out to investigate the actual behavior and the load carrying capacity of such columns. Eight full scale rectangular cross-section columns filled with lightweight aggregate concrete and normal weight aggregate concrete, four specimens each, were tested under axial loads for comparison purposes. The results showed that using lightweight concrete filling instead of normal concrete filling will reduce the weight of columns. At the same time, a high load carrying capacity is achieved

    Experimental Study on Light Weight Concrete-Filled Steel Tubes

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    Tests on steel tubular columns of rectangular and circular sections filled with normal and lightweight concrete were performed to investigate the behavior of such columns under axial loadings. Comparison between normal and lightweight concrete filled steel columns for different column cross-sections using Euro Code 4 and BS 5400 codes was also conducted. The test results showed that both types of filled columns failed due to overall buckling; while hollow steel columns failed due to local buckling at the ends. According to these results, further interest was taken onto the replacement of normal concrete by lightweight concrete due to its low specific gravity and thermal conductivity

    Development of Truss Linear Macro-Element

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    Macro-elements are among the powerful means in reducing the number of equations to be solved in finite element analysis. In the proposed method, several finite truss elements will be transformed into a single element called the macro-element. This is done by equating the potential energy of the macro-element to the potential energy of the equivalent truss finite elements. If the order of the macro-element function corresponds to the order of the structural behavior that it models, an exact solution is achieved. In this paper, a truss linear macro-element is developed. The developed macro-element was tested and the results were compared with the results of conventional finite element solutions and with closed form solutions. Excellent results were achieved with substantial reduction in the number of equations

    The role of transcranial grayscale and Doppler ultrasound examination in diagnosis of neonatal hypoxic-ischemic encephalopathy

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    Background: The role of transcranial grayscale ultrasound (TC-GSUS) and transcranial color Doppler (TCD) in the diagnosis and prognosis of neonatal hypoxic-ischemic encephalopathy (HIE) is still questionable.Objective: This study targeted to evaluate the role of TC-GSUS and TCD in diagnosis and prediction of the outcome of neonates with suspected HIE in comparison to Sarnat's clinical scoring.Patients and methods: 26 neonates with suspected HIE were clinically evaluated and the severity of HIE was categorized according to Sarnat's clinical staging. Then, all neonates underwent sonographic examinations. TC-GSUS was performed at levels of anterior, mastoid, and posterior fontanelles and the level of the temporal window.Results: Cranial biometry had negative and positive rates for HIE of 7.7% and 92.3%, respectively. Using TC-GSUS, periventricular leukomalacia, intraventricular hemorrhage, brain edema, and hydrocephalus were detected in 17, 19, 14, and 16 patients, respectively. According to the resistive index (RI) of intracranial vessels, TCD excluded HIE in 11 patients and assured diagnosis of HIE with varying severity in 15 patients. Five neonates died and four developed neurological affection during follow-up. The outcome was correlated with Sarnat’s scoring, ventricular-hemispheric ratio, and abnormalities of RI. Statistical analyses defined severity of HIE as judged by RI as the significant predictor for mortality and abnormal RI of anterior cerebral (ACA) and internal carotid arteries (ICA) are the most significant predictors of outcomes.Conclusion: TCD can diagnose HIE in neonates with high sensitivity and specificity and abnormal RI of ICA and ACA might be used as valuable diagnostic and prognostic tests

    The effects of gold nanoparticles size and concentration on viscosity, flow activation energy, dielectric and optical properties

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    This study was carried out to investigate viscosity in relation with the temperature, flow activation energy and dielectric properties for 10, 20 and 50 nm gold nanoparticles size (GNPs) in addition to absorption and fluorescence spectra at different concentrations (0.2 × 10-3 to 1 × 10-2%) in an attempt to cover and understand the toxicity and potential role of their therapeutic and diagnostic use in medical applications. 10, 20 and 50 nm GNPs dissolved in aqueous solution were purchased (Product MKN-Au, Canada) and used in this study. Mechanical parameters were measured using Brookfield LVDV-III Programmable rheometer with temperature bath controlled by a computer. 0.5 ml of each GNP size in aqueous solution was poured in the sample chamber of the rheometer. The spindle was immersed and rotated in these gold nanofluids in the speed range from 50 to 250 rpm in steps of 20 min. Viscosity of GNPs was measured at temperature of 37°C and at a gradually increase of temperature to 42ºC. UV–Visible characterization of GNPs at different concentrations from 0.2 × 10-3 to 1 × 10-2 % was performed using UV-1601 PC, UV-Visible spectrophotometer. The absorbance measurements were made over the wavelength range of 250 to 700 nm using 1 cm path length quartz cuvettes. Fluorescence characterization of GNPs was performed over the wavelength range of 250 to 700 nm using FluoroMax-2 JOBIAN YVON-SPEX. The measured viscosities for all GNP sizes decreased with increasing the temperatures from 37 to 42°C. The GNPs with larger size (50 nm) exhibited higher viscosity values compared with 10 and 20 nm GNPs. The flow activation energies (kJ/mol) for 10, 20 and 50 nm GNPs were 332.55, 415.4 and 182.2 kJ/mol, respectively. The optical properties such as absorption maxima and the absorption intensity are particle size-dependent. The fluorescence emission band for GNPs with an excitation wavelength of 308 nm and photoluminescence (PL) band centre appeared at 408 nm. With the increase of GNPs concentration at a fixed GNP size of 20 nm, the intensity of emission band positioned increased, and the trend was consistent with the changes of the corresponding surface plasmon resonance (SPR) of GNPs. The presented dielectric data indicates that GNPs have strong dielectric dispersion corresponding to the alpha relaxation region in the frequency range of 20 Hz to 100 kHz which was identified as anomalous frequency dispersion. At a constant GNP size, the absorbance was found to be proportional to the concentration of gold. This is due to the increase in the number of GNPs as well as the increase in the SPR of GNPs. An intense absorption peak was observed at wavelength of 517 nm which is generally attributed to the surface plasmon excitation of the small spherical GNPs. The incident light at 308 nm will lead to excitation of the surface plasmon coherent electronic motion as well as the d electrons. This study suggests that the relaxation of these electronic motions followed by the recombination of the sp electrons with holes in the d band leads to the fluorescence emission. These results indicate that the intensity of fluorescence emission band of GNPs was dependent on the concentration of GNPs. A rapid decrease in the dielectric constant may be attributed to the tendency of dipoles in GNPs to orient themselves in the direction of the applied field in the low-frequency range. However, in the high-frequency range, the dipoles will hardly be able to orient themselves in the direction of the applied field and hence the value of the dielectric constant is nearly constant.Key words: Gold nanoparticles, viscosity, size, temperature, dielectric, absorption, fluorescence
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