371 research outputs found

    UWB channel model in frequency domain based on propagation phenomenon analysis

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    By studying and understanding the characteristics of the channelmeasurement data, a simple Line-of-Sight Ultra Wide Bandwidth channel (UWB) model in frequency--domain (FD--model) for the small scale description of the frequency--selective channel is presented. The proposed model is motivated by analysis of physical propagation phenomenon in UWB context. The performances of proposed model are evaluated over 3 3\, GHz of frequency bandwidth. In this work, the agreement between the experimental and simulated results is only qualitative. The suitability of this channel model is evaluated by comparing channel function transfer in frequency domain (resp. time domain). Also, we have compared the τrms\tau_{rms} and τm\tau_{m} parameters for simulated channel and measured one. The evolution of number of Degree of Freedom (DoF) for simulated channel is in agreement with number of DoF for measured channel. Additionally, a simple description is presented for used measurements data. Other features of this proposed model also are discussed

    Translanguage

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    This work proposes a hypothesis that could stand as a basis for empirical investigation of translation process without losing sight of translation product. The proposed hypothesis can provide guidelines to investigate three possible concerns: First, the developmental nature of translators’ transitional constructions before settling on a “final” version. Second, the role of the non-native language in translating. Third, the type of language that is deployed in a translation.Cet article propose une hypothĂšse qui pourrait jeter les bases pour la recherche empirique du processus de traduction sans perdre de vue le produit de la traduction. L’hypothĂšse avancĂ©e fournit des principes pour trois enjeux possibles : d’abord, la nature dĂ©veloppementale des constructions transitionnelles avant d’établir une version « finale », en deuxiĂšme lieu, le rĂŽle de la langue Ă©trangĂšre dans la traduction, et enfin, le type de langue

    Ring opening polymerization of lactides and lactones by multimetallic alkyl zinc complexes derived from the acids Ph₂C(X)CO₂2H (X = OH, NH₂ )

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    The reaction of the dialkylzinc reagents R₂Zn with the acids 2,2-Ph₂C(X)(CO₂H), where X = NH₂, OH, i.e. 2,2â€Č-diphenylglycine (dpgH) or benzilic acid (benzH2), in toluene at reflux temperature afforded the tetra-nuclear ring complexes [RZn(dpg)]₄, where R = Me (1), Et (2), 2-CF₃C₆H₄ (3), and 2,4,6-F₃C₆H₂ (4); complex 2 has been previously reported. The crystal structures of 1·(2MeCN), 3 and 4·(4(C₇H₈)·1.59(H₂O)) are reported, along with that of the intermediate compound (2-CF₃C₆H₄)3B·MeCN and the known compound [ZnCl₂(NCMe)₂]. Complexes 1–4, together with the known complex [(ZnEt)₃(ZnL)₃(benz)₃] (5; L = MeCN), have been screened, in the absence of benzyl alcohol, for their potential to act as catalysts for the ring opening polymerization (ROP) of Δ-caprolactone (Δ-CL), ÎŽ-valerolactone (ÎŽ-VL) and rac-lactide (rac-LA); the co-polymerization of Δ-CL with rac-LA was also studied. Complexes 3 and 4 bearing fluorinated aryls at zinc were found to afford the highest activities

    Detection of Human Torovirus Like Particles and Adenovirus Type F in Children Attending to Babylon Maternity and Children Hospital

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    Toroviruses are enteric viruses belonging to the Nidovirales order that infect different animal species and human . Torovirus-like particales (TVLPs) that are immunologically related to BRV have been reported as etiological agents of gastroenteritis in humans. The lack of “in vitro” culture systems for toroviruses, except  for the prototype Berne virus or BEV, isolated originally from an infected horse, has hampered their study and the development of diagnostic assays. This  study  describes a real time RT-PCR method to detect  human  torovirus- like particles  (TVLPs) RNA in clinical  stool  samples using primers corresponding to the gene coding for  the nucleocapsid protein which are conserved in all (TVLPs) strains known to date. During this study, the CT value  measured  during real-time PCR analysis was used as an indication of the viral load found in the stool  sample . The assay was evaluated with 72 stool samples from children attending the Babylon maternity and children hospital. Fifty tow out of 72 (72.2%) children were shedding virus at  the time of sample collection, indicating a high incidence of TVLPs  infection  in Babylon Province. This  is the first study  attempted  for   estimating  the presence of TVLPs  in Iraq. The real time RT-PCR assay described in this study  provides a rapid, highly sensitive, specific and reliable detection and quantization  method enabling future TVLPs  epidemiological studies. In addition to that  the study included the development of real-time PCR assays for the detection of group F Adenovirus in 250 stool samples of pediatric subjects  exhibiting symptoms of diarrhea and/ or vomiting  which  were examined. PCR results of 10 positive Adenovirus group F diarrheic stool samples were confirmed by electron microscopy  examination which gave clear positive Adenovirus appearance . Till now there was no successful virus  culture growth for  isolation of diarrhegenic type 40 and 41 grow in routine cell culture . The result of this study by real time reverse transcription  – PCR  assay reflected in 72 .2 % and 58 % torovirus and adenovirus group F respectively. The genotyping results of adenoviruses(genotype 40 and 41)  highlight the significance of rapid molecular methods for the routine screening of stool samples in diagnostic laboratories to provide rapid and efficient methods . Keywords: Human Torovirus, Adenovirus, RT-PCR, Electron Microscopy

    The transformation strategy and its role in forming the structure of future architecture

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    Nature's strategies and solutions represent a significant and rich source to benefit from in creating an architectural composition that corresponds to its structure, which leads to the emergence of unexpected, vibrant, and constantly changing architectural forms due to the continuous development and progress in technology and science. Transformation is one of the strategies of nature that can be used to form the structure of future architecture, characterized by diversity and continuous formal change. Therefore, this strategy must be studied to create an adaptive architectural structure. The research aims to develop a theoretical framework that explains the role of transformation strategy in forming the structure of future architecture. The study thus reviews the basic concepts of transformation and future architecture. Then it presents the mechanisms to achieve transformation in architecture. Indicators of the conceptual framework of the transformation strategy are extracted from the knowledge provided about it. The conceptual framework represents a tool for enhancing the transformation strategy taken from nature to create innovative future architectural structures that look like living organisms, where they can perform adaptation processes and formal diversity

    Pore-Scale Displacement Efficiency during Different Salinity Water Flooding in Hydrophilic and Hydrophobic Microstructures

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    Previous macroscopic core flooding tests have shown that injecting low-salinity water improves oil recovery in sandstone and carbonate reservoirs through wettability alteration. However, consistent mechanistic clarification of the underlying physicochemical mechanisms involved in oil wettability at the pore-scale level is not fully understood. In this work, a microfluidic approach is used to provide in situ visualization of oil–brine flow to give an indication of the micromechanisms affecting oil sweep efficiency. The potential of enhancing oil recovery by low-salinity flooding at the microscale is also investigated, which would help in predicting a reservoir’s performance before committing to production processes at a large field scale. Two types of crude oils with various acid numbers were used, and hydrophilic and hydrophobic physical microstructures were used to mimic sandstones and carbonates. The results revealed a reduction by 7–10% in the residual oil for the water-wet microstructure when the seawater was diluted twice from its original concentration, apparently due to a decrease in the attractive forces. There is no change in the recovery factor for the oil-wet micromodel for the two kinds of crude oils examined. Tertiary low-salinity flooding did not show any effect on the initial wetting state of the hydrophobic surface, rendering it with a strongly oil-wet condition. It is also observed that flow dynamics of the two microstructures examined are different, as the snap-off–coalesce phenomenon dominants the flow in the water-wet system, while oil moved by a piston-like displacement with a stable or irregular front in the hydrophobic system. In contrast to some of the published macroscopic results, our pore-scale displacement shows that low-salinity flooding seems to be an unsuitable choice for enhanced oil recovery for strongly oil-wet reservoirs

    Finite element method for dynamic modelling of an underwater flexible single-link manipulator

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    In order to control the angular displacement of the hub and to suppress the vibration at the end point of an underwater flexible single-link manipulator system efficiently, it is required to obtain an adequate model of the structure. In this study, a mathematical model of an underwater flexible single-link manipulator system has been developed and modelled as a pinned-free, an Euler-Bernoulli flexible beam using finite element method based on Lagrangian approach analysis. Damping, hub inertia and payload are incorporated in the dynamic model, which is then represented in a state-space form. The simulation algorithm was developed using matlab and its performance, on the basis of accuracy in characterizing the behavior of the manipulator, is assessed

    Distribution Of Some Heavy Metals In Water,Sediment & Fish Cyprinus carpio in Euphrates River Near Al- Nassiriya City Center South Iraq .

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    The heavy metals Cd, Cu, Fe, pb, and Zn were determined in dissolved and particulate phases of the water,in addition to exchangeable and residual phases of the sediment and in the selected organs of the fish Cyprinus carpio collected from the Euphrates River near Al-Nassiriya city center south of Iraq during the summer period / 2009 .Also sediment texture and total organic carbon(TOC) were measured. Analysis emploing a flam Atomic Absorption Spectrophotometers . The mean regional concentrations of the heavy metals in dissolved (”g/l) and particulate phases (”g/gm) dry weight were Cd (0.15,16.13) ,Cu (0.59,24.48) ,Fe (726,909.4) ,Pb (0.20, 49.95) and Zn (2.5,35.62) respectively,and those for exchangeable and residual phases of the Sediment were Cd (0.2,0.1) ,Cu (13.75,16.65) ,Fe (683 , 1351 ) ,Pb (10.1,1.07) and Zn (7.3,16.75)”g/gm dry weight respectively. The heavy metals concentrations in C. carpio organs followed the trend gill > liver > kidney> muscles . The mean concentration in the muscles were Cd (ND) , Cu (0.07) , Fe (4.7) , pb (0.06) and Zn (6.4) (”g/gm) dry weight . The statistical analysis proved a significant correlation between metal concentration in the sediment and total organic carbon, also a positive correlation was proved between its concentrations in the liver organ and the water (particulate phase) . In conclusion the trace metals concentration in particulate phase were higher than its concentration in the dissolved phase . The fish organs showed variations in the metals concentration and the muscle organs showed less concentration than the other organs

    Impact of Climate Changes on the Hydrochemistry of Razaza Lake and Rahaliya – Shithatha Springs – Central Iraq

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    The climate parameters, rainfall, temperature data for more than forty years for three Iraqi meteorological stations (Baghdad, Basra, and Mosul) were studied .The results show good evidence of climate change indicated by the remarkable decrease of the average means annual rainfall in the studied stations, with the remarkable increase of the average minimum annual temperature. The impact of the climatic change on the hydrochemistry of Razaza lake and Rahaliya – Shithatha springs was obvious in increasing the water salinity as studied for years 1995 and 2013. The average mean annual rainfall for ten years intervals indicate that there were a remarkable decrease in amount of rainfall from 90 mm for the period 1992-2001 to about 71 mm for the period 2002- 2013.  The Razzaza lake water has indicated that chloride group and one major family (Chloride-sodium family) is the dominant for years 1995 and 2013 with increase of Mg ions during 2013. The Rahaliya – Shithatha springs’ water has showed that the sulphate and chloride groups are dominant for years 1995 and 2013, with increase of sulphate group to 80% during 2013. Keywords: Climatic changes, hydrochemistry, Razaza lake and Rahaliya – Shithatha springs, Iraq
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