446 research outputs found
Treatment of produced water using an enhanced electrocoagulation process
Produced water generated during oilfield processes is considered as a major problem that requires solving due to its high salinity and pollutant contents. Electrocoagulation is one of the promising processes for produced water treatment. In this study, steel slag was used as an additional coagulant in the electrocoagulation process for the produced water treatment. The impact of current density, reaction time and the amount of added steel slag were investigated. For a current density of 10 mA/cm2 at a 10 minute reaction time, it was found that the slag sample had a total suspended solids removal of 90% compared to 55.7% for the pure sample. As for the turbidity, the slag sample showed an 85.9% removal, and the pure sample showed an 80.1% removal. The oil and grease removal percentage were almost the same for the sample with and without the slag at 98.9% removal. For the reaction time, it was found that as the reaction time increases the percentage removal for the total suspended solids and turbidity increases to a certain extent. The optimum removal percentage was obtained at a reaction time of 30 minutes. It was found that the slag sample had a 94.8% and a 92.5% total suspended solids and turbidity removal percentages, respectively, while the pure sample had a lower removal percentage of 90% and 90.3%, respectively. The oil and grease removal percentage were similar for both samples where it was 98.6% for the slag sample, and 98.9% for the pure sample. The impact of the amount of added slag was studied for 3 different concentration: 5g/L, 10g/L, and 15g/L. It was found that the optimum removal percentage of suspended solids, turbidity, and oil and grease were 83%, 55%, 96.5%, respectively, using a slag weight of 5 grams
Factors Affecting Sustainable Performance of Construction Projects during Project Life Cycle Phases
Sustainable development (SD) is one of the main challenges faced by the construction industry, which has acquired global attention. Sustainable performance (SP) of a construction project during its life cycle (LC) is considered crucial to achieve the SD. The aim of this paper is to investigate the factors affecting sustainable performance of construction projects throughout project life cycle phases in the Gaza Strip. A total of 53 sustainable factors (economic, social, and environmental sustainable factors) were identified through extensive literature review and confirmed by experts’ interviews and a pilot study. These factors are classified in relation to the project life cycle phases; inception phase, design phase, construction phase, operation phase, and demolition phase. A structured questionnaire survey is employed in this study for primary data collection. A total of 119 questionnaires were distributed randomly to engineers working in construction projects in the Gaza Strip to solicit their views regarding the factors affecting sustainable performance of construction projects throughout project life cycle phases. The results revealed that five factors among the top ten factors that impacting the sustainable performance of construction projects are classified under the construction phase, which confirmed that the construction process has the most effect on the projects SP. Three factors are classified under the inception phase, which assured that the inception of a potential project has a considerable effect projects. In addition, one factor was classified under operation phase and one factor was classified under demolition phase. The most common factors
Objectivity and Orgasm
Lloyd (2005) analyzes every proposed evolutionary explanation of female orgasm and argues that all but one suffer from serious evidential errors. Lloyd attributes these errors to two main biases: androcentrism and adaptationism. But, there is an alternative explanation for the discrepancies in the case of the female orgasm that Lloyd’s analysis overlooks. I present and argue for the plausibility of this alternative explanation. In short, the alternative explanation is that an imprecise definition of orgasm is what’s partially responsible for the missteps in this research domain. Further, Lloyd takes her analysis to support Lonigno’s (1990) Contextual Empiricist model. Insofar as Lloyd’s analysis fails to capture an important part of scientific practice the alternative explanation picks out, this might reveal a shortcoming for Contextual Empiricism.Master of Art
Antigen presenting cells (APCs) from thermally injured and/or septic rats modulate CD4+ T cell responses of naive rat
AbstractRegulation of immune response is marked by complex interactions among the cells that recognize and present antigens. Antigen presenting cells (APCs), the antigen presenting cell component of the innate immune response plays an important role in effector CD4+ T cell response. Thermal injury and/or superimposed sepsis in rats' leads to suppressed CD4+ T cell functions. We investigated modulations of CD4+ T cell function by APCs (purified non-T cells) from thermally injured and/or septic rats. Rats were subjected to 30% total body surface area scald burn or exposed to 37 °C water (Sham burn) and sepsis was induced by cecal-ligation and puncture (CLP) method. At day 3 post-injury animals were sacrificed and CD4+ T cells and APCs from mesenteric lymph nodes (MLN) were obtained using magnetic microbead isolation procedure. APCs from injured rats were co-cultured with sham rat MLN CD4+ T cells and proliferative responses (thymidine incorporation), phenotypic changes (Flow cytometry), IL-2 production (ELISA) and CTLA-4 mRNA (RT-PCR) were determined in naive rat CD4+ T cells. The data indicate that APCs from thermally injured and/or septic rats when co-cultured with CD4+ T cells suppressed CD4+ T cell effector functions. This lack of CD4+ T cell activation was accompanied with altered co-stimulatory molecules, i.e., CD28 and/or CTLA-4 (CD152). In conclusion, our studies indicated that defective APCs from thermally injured and/or septic rats modulate CD4+ T cell functions via changes in co-stimulatory molecules expressed on naive CD4+ T cells. This altered APC: CD4+ T cell interaction leads to suppressed CD4+ T cell activation of healthy animals
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Why has the Arab League failed as a regional security organisation? An analysis of the Arab League¿s conditions of emergence, characteristics and the internal and external challenges that defined and redefined its regional security role.
This study presents a detailed examination of the Arab League¿s history, development, structure and roles in an effort to understand the cause of its failure as a regional security organisation. The research¿s point of departure is a questioning of the nature and scope of this failure in terms of the interplay between the conditions under which it was formed and the many actors and dynamics that had a long term-impact on the prospects for the League. To this end, the study looks at the League¿s conditions of emergence and Arab-Arab relations with the focus on Arab national security as the main concept determining its security role. The research synthesises methods of analysis from the existing literature and schools of thought so as to identify where and why failure and success occurred in relation to international relations theories, the security and international organisations literature, and comparable international models. The development and conditions affecting the League as discussed in the research demonstrate that none of the existing broad theories or approaches can fully explain the League¿s failure; however, the constructivist approach, although never before applied in this context, is shown to offer the most relevant approach for explaining this organisation and its unique parameters. The research also examines the role played by the Arab League in regional peacekeeping and conflict prevention in the context of Arab national security, with Palestine as a case study
Noise Level Estimation for Digital Images Using Local Statistics and Its Applications to Noise Removal
In this paper, an automatic estimation of additive white Gaussian noise technique is proposed. This technique is built according to the local statistics of Gaussian noise. In the field of digital signal processing, estimation of the noise is considered as pivotal process that many signal processing tasks relies on. The main aim of this paper is to design a patch-based estimation technique in order to estimate the noise level in natural images and use it in blind image removal technique. The estimation processes is utilized selected patches which is most contaminated sub-pixels in the tested images sing principal component analysis (PCA). The performance of the suggested noise level estimation technique is shown its superior to state of the art noise estimation and noise removal algorithms, the proposed algorithm produces the best performance in most cases compared with the investigated techniques in terms of PSNR, IQI and the visual perception
Analysis of nuclear fiber cell compaction in transparent and cataractous diabetic human lenses by scanning electron microscopy
BACKGROUND: Compaction of human ocular lens fiber cells as a function of both aging and cataractogenesis has been demonstrated previously using scanning electron microscopy. The purpose of this investigation is to quantify morphological differences in the inner nuclear regions of cataractous and non-cataractous human lenses from individuals with diabetes. The hypothesis is that, even in the presence of the osmotic stress caused by diabetes, compaction rather than swelling occurs in the nucleus of diabetic lenses. METHODS: Transparent and nuclear cataractous lenses from diabetic patients were examined by scanning electron microscopy (SEM). Measurements of the fetal nuclear (FN) elliptical angles (anterior and posterior), embryonic nuclear (EN) anterior-posterior (A-P) axial thickness, and the number of EN fiber cell membrane folds over 20 μm were compared. RESULTS: Diabetic lenses with nuclear cataract exhibited smaller FN elliptical angles, smaller EN axial thicknesses, and larger numbers of EN compaction folds than their non-cataractous diabetic counterparts. CONCLUSION: As in non-diabetic lenses, the inner nuclei of cataractous lenses from diabetics were significantly more compacted than those of non-cataractous diabetics. Little difference between diabetic and non-diabetic compaction levels was found, suggesting that diabetes does not affect the degree of compaction. However, consistent with previous proposals, diabetes does appear to accelerate the formation of cataracts that are similar to age-related nuclear cataracts in non-diabetics. We conclude that as scattering increases in the diabetic lens with cataract formation, fiber cell compaction is significant
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