249 research outputs found

    Optical Properties Of Treated And Untreated Monocrystalline p- Si<L11>,p-Si<100>, n-Si<l11> and n-Si<100) Wafers In The Visible Region At Room Temperature.

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    Silicon only based materials have dominated the electronic applications for the past few decades and now the materials have almost reached its saturation point

    On Some Shrinkage Techniques For Estimating The Parameters Of Exponential Distribution

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    A variety of shrinkage methods have been proposed for estimation of some unknown parameter by considering estimators based on a prior guess of the value of the parameter. We compare some of the shrunken estimators for the parameters^ and 9 of the exponential distribution through simulatio

    Pre and Early Post-Operative Iron Assessment in Obese Patients Underwent Laparoscopic Sleeve Gasterctomy

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    Obesity is a chronic disease associated with mortality and morbidity. Bariatric surgery (BS) as a long-term weight reduction treatment has been increased. This study investigated the early state of iron storage and deficiency in patients underwent laparoscopic sleeve gastrectomy (LSG). Thirty patients were selected as a prospective study underwent LSG according to specialized inclusion and exclusion criteria at Soran Private Hospital in Erbil, from 1/1/2021 to 1/9/2021 after signing a consent form. All selected patients underwent preoperative and three months’ post-operative hemoglobin (Hb), mean corpuscular volume (MCV), and serum ferritin (SF) assessments. They were instructed to follow specialized diet regimen for three months’ post-operative and not to take any drugs and supplements. Results showed a strong positive correlation between preoperative and postoperative assessment for both Hb and MCV respectively (r= 0.72; P &lt; 0.001), (r= 0.76; P &lt; 0.001), and a moderate correlation for SF (r= 0.41; P &lt; 0.024). &nbsp;Significant difference (P &lt; 0.05) was found between preoperative and postoperative for the three markers (Hb, MCV and SF). Their values were decreased from preoperative to postoperative for the majority of the cases, but they were still within the normal range. The finding demonstrated that after three months from LSG, no patients showed iron deficiency anaemia. However, there was decrease in SF level which indicated that the storage capacity of iron was decreasing. This suggest that the iron supplement has to be started since the food regime followed in by the patients was not sufficient to maintain normal iron level

    Performance of a local signalized intersection for handling traffic operation in Baghdad City

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    The inspection of the flexibility and performance of a local signalized intersection in managing traffic operation in Baghdad city is the main target of this study. Andalus intersection is one of the important local intersections in Bagdad city which recorded remarkable traffic congestion problem now a days and have been chosen in this study as a part of continuous studies due to its vital location. Smart Traffic Analysis (STA) software is used to give an aspect to the inefficient performance of the Andalus signalized intersection having three approached links and four exit legs while SYNCHRO software is used to simulate the data analysis and offer different alternative solutions to solve the congestion problem. From the obtained data analysis it has been found that the best suggested alteration for handling the current traffic volume of each studied intersection approach is the signalized intersection with optimum cycle time combined with the addition of two lanes, where the mean delay for the entire intersection can be reduced by approximately 26% by applying alteration No.1 while the mean delay for the entire intersection can be reduce approximately by 31% by applying alteration No.2. Furthermore, the queue length for the entire intersection can be reducing by approximately 6% and 17% for alteration No.1 and No.2 respectively

    L-CAQ: Joint link-oriented channel-availability and channel-quality based channel selection for mobile cognitive radio networks

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    Channel availability probability (CAP) and channel quality (CQ) are two key metrics that can be used to efficiently design a channel selection strategy in cognitive radio networks. For static scenarios, i.e., where all the users are immobile, the CAP metric depends only on the primary users' activity whereas the CQ metric remains relatively constant. In contrast, for mobile scenarios, the values of both metrics fluctuate not only with time (time-variant) but also over different links between users (link-variant) due to the dynamic variation of primary- and secondary-users' relative positions. As an attempt to address this dynamic fluctuation, this paper proposes L-CAQ: a link-oriented channel-availability and channel-quality based channel selection strategy that aims to maximize the link throughput. The L-CAQ scheme considers accurate estimation of the aforementioned two channel selection metrics, which are governed by the mobility-induced non-stationary network topology, and endeavors to select a channel that jointly maximizes the CAP and CQ. The benefits of the proposed scheme are demonstrated through numerical simulation for mobile cognitive radio networks

    The African Political Business Cycle: Varieties of Experience

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    We seek to understand both the incidence and the impact of the African political business cycle in the light of a literature which has argued that, with major extensions of democracy since the 1990s, the cycle has both become more intense and has made African political systems more fragile. With the help of country-case studies, we argue, first, that the African political business cycle is not homogeneous, and occurs relatively infrequently in so-called ‘dominant-party systems’ where a pre-election stimulus confers little political advantage. Secondly, we show that, in those countries where a political cycle does occur, it does not necessarily cause institutional damage. Whether it does or not depends not so much on whether there is an electoral cycle as on whether this cycle calms or exacerbates fears of an unjust allocation of resources. In other words, the composition of the pre-election stimulus, in terms of its allocation between different categories of voter, is as important as its size

    A Mini-Review of Enhancing Ultrafiltration Membranes (Uf) for Wastewater Treatment: Performance and Stability

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    The scarcity of freshwater resources in many regions of the world has contributed to the emergence of various technologies for treating and recovering wastewater for reuse in industry, agriculture, and households. Deep wastewater treatment from oils and petroleum products is one of the difficult tasks that must be solved. Among the known technologies, UF membranes have found wide industrial application with high efficiency in removing various pollutants from wastewater. It is shown that the search for and development of highly efficient, durable, and resistant to oil pollution UF membranes for the treatment of oily wastewater is an urgent research task. The key parameters to improve the performance of UF membranes are by enhancing wettability (hydrophilicity) and the antifouling behavior of membranes. In this review, we highlight the using of ultrafiltration (UF) membranes primarily to treat oily wastewater. Various methods of polymer alterations of the UF membrane were studied to improve hydrophilicity, the ability of antifouling the membrane, and oil rejection, including polymer blending, membrane surface modification, and the mixed membrane matrix. The influence of the type and composition of the hydrophilic additives of nanoparticles (e.g., Multiwall carbon nanotubes (MWCNT), graphene oxide (GO), zinc oxide (ZnO), and titanium dioxide (TiO2 ), etc.) was investigated. The review further provides an insight into the removal efficiency percent. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    A newly developed integrative bio-inspired artificial intelligence model for wind speed prediction

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    Accurate wind speed (WS) modelling is crucial for optimal utilization of wind energy. NumericalWeather Prediction (NWP) techniques, generally used for WS modelling are not only less cost-effective but also poor in predicting in shorter time horizon. Novel WS prediction models based on the multivariate empirical mode decomposition (MEMD), random forest (RF) and Kernel Ridge Regression (KRR) were constructed in this paper better accuracy in WS prediction. Particle swarm optimization algorithm (PSO) was employed to optimize the parameters of the hybridized MEMD model with RF (MEMD-PSO-RF) and KRR (MEMD-PSO-KRR) models. Obtained results were compared to those of the standalone RF and KRR models. The proposed methodology is applied for monthly WS prediction at meteorological stations of Iraq, Baghdad (Station1) and Mosul (Station2) for the period 1977-2013. Results showed higher accuracy of MEMD-PSO-RF model in predicting WS at both stations with a correlation coefficient (r) of 0.972 and r D 0.971 during testing phase at Station1 and Station2, respectively. The MEMD-PSO-KRR was found as the second most accurate model followed by Standalone RF and KRR, but all showed a competitive performance to the MEMD-PSO-RF model. The outcomes of this work indicated that the MEMD-PSO-RF model has a remarkable performance in predicting WS and can be considered for practical applications

    Groundwater Hydrogeochemical and Quality Appraisal for Agriculture Irrigation in Greenbelt Area, Iraq

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    This study highlights the groundwater hydrogeochemical characteristics and processes (hydrochemistry characteristics, ion exchange, and salinization) and quality suitability assessment for irrigation purposes from five wells in the Greenbelt area located in northwestern Al‐Najaf Gov-ernorate, Iraq. The suitability of groundwater for irrigation was assessed based on the irrigation water quality index (IWQI) for thirteen parameters and groundwater quality indices such as total dissolved solids (TDS), electrical conductivity (EC), sodium adsorption ratio (SAR), soluble sodium percent (SSP), residual sodium carbonate (RSC), total hardness (TH), permeability index (PI), potential salinity (PS), Kelley’s ratio (KR), and magnesium hazard ratio (MHR). The IWQI’s average values ranged between 76–139. The results of IWQI for the first and second sampling sites showed values of 139 and 104, respectively, indicating that the groundwater was unsuitable and unsafe for irrigation. In contrast, the IWQI for the third, fourth, and fifth sites were 83, 97, and 76, respectively, indicating that the groundwater was safe and possibly used for irrigation. The EC, TDS, PS, and MHR indices were all found to be unsuitable for irrigation in all five sites, and the KR index was also found to be unsuitable for agricultural irrigation in about 80% of the sites, while it was found that the indices of SAR, SSP, RSC, PI, and TH for all sites were suitable and safe for irrigation. As a result of this study, it has been determined that groundwater in the study area is unsuitable for agricultural irrigation. For sustainable groundwater exploitation, it is advised that a continuous water‐quality‐monitoring program should be implemented, as well as the development of suitable management practices. © 2022 by the authors. Licensee MDPI, Basel, Switzerland
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