67 research outputs found

    Factors affecting quality during the construction phase in Iraqi government companies

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    Construction projects play a significant part in the development of any country and quality is one of the important factors in the success of the construction industry. There is a lack of understanding of quality is the problem in the construction industry in Iraq, but the main problem is the absence of good quality supervision of the construction industry. Based on the literature review yielded managers, designers, and contractors with necessary information needed to better manage the quality of a construction project by identifying the factors that affect process quality of construction projects and to rank them by degree of importance and develop a model to represent the factors affecting the overall quality of Construction projects. This study was based on questionnaire surveys, which was designed based on literature review. After, validation a total 109 questionnaires were collected among project manager, quality engineer, and general manager in Baghdad, the capital city of Iraq. Data were analysed using descriptive statistics and multiple regression analysis applying SPSS software Ver.21. The results of data analysis indicated that the level of importance all factors were more than a moderate level and the highest level which was almost high belonged to the material. The other factors, including Quality systems, Owner, Design, Equipment, Labors and contractor almost ranged between 3.69-3.75. Based on multiple regression analysis among all factors only “contractor” did not show any significant effect on quality in construction projects. The highest effect belonged to, quality systems with (β=0.289, P value<0.001) and then owner and materials followed by design, equipment, site staff and the lowest impact was observed for labor factor (β=0.137, P value=0.049)

    Synthesis and characterization of some biological active transition metal complexes of Schiff base derived from cefixime with mixed ligand 8-hydroxy quinoline

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    The aim of the work is synthesis and characterization of bidentate ligand [dipotassium sodium7-((E)-2-(2-((Z)-1-carboxylatoethylideneamino)thiazol-4-yl)-2 (carboxylatemethoxyimino) acet amido)-8-oxo-3-vinyl-5- thia-1-azabicyclo[4.2.0] oct-2- ene-2- carboxylate] [Nak2L], from the reaction of cefixime with sodium pyruvet to produce the ligand [Nak2L], the reaction was carried out in methanol as a solvent under reflux. The prepared ligand [Nak2L] which was characterized by FT-IR, UV-Vis spectroscopy, 1H, 13C-NMR spectra, Mass spectra, (C.H.N) and melting point. The mixed ligand complexes were prepared from ligand [Nak2L] was used as a primary ligand while 8-hydroxy quinoline [Q] was used as a secondary ligand with metal ion M(?).Where M(?) = (Mn ,Co ,Ni ,Cu ,Zn and Cd) at reflux ,using methanol as a solvent, KOH as a base. Complexes of the composition [(M)2(Q)2(KL)(H2O)4] with (2:2:1) molar ratio were prepared. All the complexes were characterized by spectroscopic methods (FT-IR, UV-Vis spectroscopy) along with elemental analysis (A.A), chloride content and melting point measurements were carried out, together with conductivity and magnetic susceptibility. These measurements showed octahedral geometry around (Mn??, Co??, Ni??, Cu??, Zn?? and Cd??) ions. The biological activity of the ligands [NaK2L], [Q] and complexes [(M)2(Q)2(KL)(H2O)4] were studied by using inhibition method

    A Taxonomy of Virtualization Security Issues in Cloud Computing Environments

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    Objectives: To identify the main challenges and security issues of virtualization in cloud computing environments. It reviews the alleviation techniques for improving the security of cloud virtualization systems. Methods/ Statistical Analysis: Virtualization is a fundamental technology for cloud computing, and for this reason, any cloud vulnerabilities and threats affect virtualization. In this study, the systematic literature review is performed to find out the vulnerabilities and risks of virtualization in cloud computing and to identify threats, and attacks result from those vulnerabilities. Furthermore, we discover and analyze the effective mitigation techniques that are used to protect, secure, and manage virtualization environments. Findings: Thirty vulnerabilities are identified, explained, and classified into six proposed classes. Furthermore, fifteen main virtualization threats and attacks ar defined according to exploited vulnerabilities in a cloud environment. Application/Improvements: A set of common mitigation solutions are recognized and discovered to alleviate the virtualization security risks. These reviewed techniques are analyzed and evaluated according to five specified security criteria

    Low complexity DCO-FBMC visible light communication system

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    Filter Bank Multicarrier (FBMC) is a new waveform candidate in the visible light communication system (VLC). FBMC is a distinctive kind of multi-carrier modulation that can be regarded as an alternative to orthogonal frequency Division Multicarrier (OFDM) with CP (cyclic prefix). DCO-FBMC (DC-bias optical FBMC) has recently been used in VLC, because it overcomes all defects in the optical-OFDM system and has high spectral efficiency. but at the same time the traditional DCO-FBMC suffers from high complexity due to the use of Hermitian Symmetry for real signal, by using 2N-point subcarrier IFFT (Inverse Fast Fourier Transformer) in the modulator, and the output is N-point subcarrier FFT (Fast Fourier Transform) in the demodulator. In this paper, for the first time, the possibility of minimizing complexity and generating a real signal without the use of Hermitian Symmetry or any other technique has been verified. The proposed technology provides 50% of the size of the IFFT / FFT and this results in a significant reduction in power consumption and occupied chip area

    Influence of Metal Ion Doping of Zinc Oxide Photoanode on the Efficiency of Dye Sensitized Solar Cell

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    Doping zinc oxide nanoparticles (ZnO NPs) and doped with Niobium (Nb5+) and Aluminium (Al3+) ions were synthesized to use as a photoanode for the Dye Sensitized Solar Cells (DSSCs). The structural of the synthetized samples were examined via X-ray diffraction (XRD). The XRD patterns for all samples confirmed the hexagonal wurtzite structure. The DSSCs based on the undoped and doped ZnO NPs were fabricated and assembled. Scanning electron microscopic (SEM) images were measured for all fabricated devices. The doping Nb5+ and Al3+ ions influenced the performance of the DSSCs. ZnO NPs doped Nb5+ led to higher surface area and hence more dye loading and retard the recombination of charges, which enhanced the open circuit voltage

    Idiopathic benign retroperitoneal cyst: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Retroperitoneal cysts are uncommon, with an estimated incidence of 1/5750 to 1/250,000.</p> <p>Case presentation</p> <p>A male patient was admitted with an abdominal pain, jaundice and fever. Clinical examination and investigations confirmed an idiopathic benign retroperitoneal cyst. He underwent surgery and was discharged after making good recovery.</p> <p>Conclusion</p> <p>Retroperitoneal cysts are very rare, and most of the time they are discovered incidentally. Patients may be asymptomatic or present with abdominal pain, referred pain to the legs or weight loss. Imaging may help diagnose these lesions, but surgery is the keystone in confirming the diagnosis. This case is very rare and very educational as it highlights an unusual presentation of a benign retroperitoneal cyst. In our patient, the course of the disease was unique as the patient presented with jaundice.</p

    Demystifying Smoker's Paradox: A Propensity Score-Weighted Analysis in Patients Hospitalized With Acute Heart Failure.

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    Background Smoker's paradox has been observed with several vascular disorders, yet there are limited data in patients with acute heart failure (HF). We examined the effects of smoking in patients with acute HF using data from a large multicenter registry. The objective was to determine if the design and analytic approach could explain the smoker's paradox in acute HF mortality. Methods and Results The data were sourced from the acute HF registry (Gulf CARE [Gulf Acute Heart Failure Registry]), a multicenter registry that recruited patients over 10 months admitted with a diagnosis of acute HF from 47 hospitals in 7 Middle Eastern countries. The association between smoking and mortality (in hospital) was examined using covariate adjustment, making use of mortality risk factors. A parallel analysis was performed using covariate balancing through propensity scores. Of 5005 patients hospitalized with acute HF, 1103 (22%) were current smokers. The in-hospital mortality rates were significantly lower in current smoker's before (odds ratio, 0.71; 95% CI, 0.52-0.96) and more so after (odds ratio, 0.47; 95% CI, 0.31-0.70) covariate adjustment. With the propensity score-derived covariate balance, the smoking effect became much less certain (odds ratio, 0.63; 95% CI, 0.36-1.11). Conclusions The current study illustrates the fact that the smoker's paradox is likely to be a result of residual confounding as covariate adjustment may not resolve this if there are many competing prognostic confounders. In this situation, propensity score methods for covariate balancing seem preferable. Clinical Trial Registration URL: https://www.clinicaltrials.gov/. Unique identifier: NCT01467973.Gulf CARE (Gulf Acute Heart Failure Registry) is an investigator- initiated study conducted under the auspices of the Gulf Heart Association and funded by Servier, Paris, France; and (for centers in Saudi Arabia), by the Saudi Heart Association (The Deanship of Scientific Research at King Saud University, Riyadh, Saudi Arabia [research group number: RG -1436- 013]). This does not alter our adherence to policies on sharing data and materials; and the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The publication of this article was funded by the Qatar National Library

    Structure and in silico simulations of a cold-active esterase reveals its prime cold-adaptation mechanism

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    Here we determined the structure of a cold active family IV esterase (EstN7) cloned from Bacillus cohnii strain N1. EstN7 is a dimer with a classical α/β hydrolase fold. It has an acidic surface that is thought to play a role in cold-adaption by retaining solvation under changed water solvent entropy at lower temperatures. The conformation of the functionally important cap region is significantly different to EstN7's closest relatives, forming a bridge-like structure with reduced helical content providing greater access to the active site through more than one substrate access tunnel. However, dynamics do not appear to play a major role in cold adaption. Molecular dynamics at different temperatures, rigidity analysis, normal mode analysis and geometric simulations of motion confirm the flexibility of the cap region but suggest that the rest of the protein is largely rigid. Rigidity analysis indicates the distribution of hydrophobic tethers is appropriate to colder conditions, where the hydrophobic effect is weaker than in mesophilic conditions due to reduced water entropy. Thus, it is likely that increased substrate accessibility and tolerance to changes in water entropy are important for of EstN7's cold adaptation rather than changes in dynamics
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