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The Causes Influencing the Occurrence of Variation Orders in the Construction of Buildings
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In the construction of buildings usually, problems occur because of the causes of change orders. The main causer of change orders is the owners, consultants, and contractors. These changes lead to conflicts among them which result in influencing building projects. Therefore, it is necessary to analyze the causes of change orders to reduce them and facilitate management. This paper determines the most critical factors that cause change orders from a different point of view, a consulting owner and a contractor, and a study of the reality of the management of change orders when constructing public buildings. The method employed in this research is a field survey using interviews with experts working in the construction of public buildings. Furthermore, the questionnaire was distributed manually and electronically.

In conclusion, it would appear that the causes of change orders have been hierarchically according to the viewpoint of the owner, contractor, and consultant. The analysis leads to the following conclusions: Agreement of viewpoints owners, contractors, and consultants on the critical causes of variation orders were: ( the difficult financial situation - change material specifications to benefit the project - technical necessity  - the nature of the site). Moreover, the point of view (owners and contractors) on the essential factors that cause change orders were: (preparing a bill of quantities is inaccurate - weak consultant guess ). In contrast, the consultant's point of view differs, as he considers these causes ineffective. It can be interpreted that the consultant sees these factors as insignificant because of his duty to implement the bill of quantities and designs. This research paper concludes that a complex causal relationship exists between the causes of change orders. The relative importance index (RII) for variation order causes varies among different groups' viewpoints (owners, contractors, and consultants).

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Publication Date
Mon Jun 04 2018
Journal Name
Baghdad Science Journal
Effects of Non-Thermal Argon Plasma Produced at Atmospheric Pressure on the Optical Properties of CdO Thin Films
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In this paper the effect of nonthermal atmospheric argon plasma on the optical properties of the cadmium oxide CdO thin films prepared by chemical spray pyrolysis was studied. The prepared films were exposed to different time intervals (0, 5, 10, 15, 20) min. For every sample, the transmittance, Absorbance, absorption coefficient, energy gap, extinction coefficient and dielectric constant were studied. It is found that the transmittance and the energy gap increased with exposure time, and absorption. Absorption coefficient, extinction coefficient, dielectric constant decreased with time of exposure to the argon plasma

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Publication Date
Sat Dec 02 2023
Journal Name
Journal Of Engineering
Evaluation of the Stability and Flow of Asphalt Concrete Produced with Waste Brick Tile Powder as a Filler
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The utilization of recycled brick tile powder as a replacement for conventional filler in the asphalt concrete mix has been studied in this research. This research evaluates the effectiveness of recycled brick tile powder and determines its optimum replacement level. Using recycled brick tile powder is significant from an environmental standpoint as it is a waste product from construction activities. Sixteen asphalt concrete samples were produced, and eight were soaked for a day. Samples contained 5% Bitumen, 2% to 5% brick tile powder, and conventional stone dust filler. The properties of samples were evaluated using the Marshall test. It was observed that the resistance to stiffness and deformation of asphalt concrete

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Publication Date
Tue Oct 01 2024
Journal Name
Journal Of Physics: Conference Series
An Effect of Al on the Properties of ZnIn<sub>2</sub>Se<sub>4</sub> Thin Film
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Abstract<p>Zinc-indium-selenide ZnIn<sub>2</sub>Se<sub>4</sub> (ZIS) ternary chalcopyrite thin film on glass with a 500 nm thickness was fabricated by using the thermal evaporation system with a pressure of approximately 2.5×10<sup>−5</sup> mbar and a deposition rate of 12 Å/s. The effect of aluminum (Al) doping with 0.02 and 0.04 ratios on the structural and optical properties of film was examined. The utilization of X-ray diffraction (XRD) was employed to showcase the influence of aluminum doping on structural properties. XRD shows that thin ZIS-pure, Al-doped films at RT are polycrystalline with tetragonal structure and preferred (112) orientation. Where the </p> ... Show More
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Publication Date
Fri Dec 15 2023
Journal Name
Journal Of Baghdad College Of Dentistry
Comparing the effectiveness of using three different re-mineralizing pastes on remineralisation of artificially induced white spot lesion
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Background: This study aimed to compare the surface microhardness (MH) and mineral content of white spot lesions(WSLs) after using bioactive glass (BAG)casein phosphopep-tides-amorphous calcium phosphate(CPP-ACP),and nanohydroxyapatite(Nano-HAP) under pHcycling. Material and method:18 sound maxillary first premolar were used for the study.10 were selected for the vickers microhardness test, For Energy-dispersive X-ray spectroscopy analysis (EDX), the remaining 8 premolar teeth were used, 40 sections of enamel blocks (Four from each tooth) were produced from the middle part of the buccal and palatal surfaces of teeth for MH test while 48 sections of enamel blocks (Six from each tooth) were produced for EDX analysis. Enamel slabs were

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Publication Date
Sat Dec 02 2023
Journal Name
Journal Of Engineering
Discussion on the Structural Design Index and Design Method of Widening and Splicing Lane of Old Asphalt Pavement
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The splicing design of the existing road and the new road in the expansion project is an important part of the design work. Based on the analysis of the characteristics and the load effect of pavement structure on splicing, this paper points out that tensile crack or shear failure may occur at the splicing under the repeated action of the traffic load on the new/old pavement. According to the current structure design code of asphalt pavement in China, it is proposed that the horizontal tensile stress at the bottom of the splicing layer and the vertical shear stress at other layers of the splicing line should be controlled by adjusting the position and size of the excavated steps in addition to the conventional design ind

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Publication Date
Mon Apr 01 2019
Journal Name
Journal Of Engineering
Effect of Thickness Variable on the Bending Analysis of Rotating Functionally polymer Graded Carbon Nanotube Reinforced Cylindrical Panels
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This study offers the elastic response of the variable thickness functionally graded (FG) by single walled carbon nanotubes reinforced composite (CNTRC) moderately thick cylindrical panels under rotating and transverse mechanical loadings. It’s considered that, three kinds of distributions of carbon nanotubes which are uniaxial aligned in the longitudinal direction and two functionally graded in the transverse direction of the cylindrical panels. Depending on first order shear deformation theory (FSDT), the governing equations can be derived. The partial differential equations are solved by utilizing the technique of finite element method (FEM) with a program has been built by using FORTRAN 95. The results are calculat

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Publication Date
Fri Jan 11 2019
Journal Name
Iraqi Journal Of Physics
Effect of thickness on the optical properties of ZnO thin films prepared by pulsed laser deposition technique (PLD)
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Zinc Oxide (ZnO) thin films of different thickness were prepared
on ultrasonically cleaned corning glass substrate, by pulsed laser
deposition technique (PLD) at room temperature. Since most
application of ZnO thin film are certainly related to its optical
properties, so the optical properties of ZnO thin film in the
wavelength range (300-1100) nm were studied, it was observed that
all ZnO films have high transmittance (˃ 80 %) in the wavelength
region (400-1100) nm and it increase as the film thickness increase,
using the optical transmittance to calculate optical energy gap (Eg
opt)
show that (Eg
opt) of a direct allowed transition and its value nearly
constant (~ 3.2 eV) for all film thickness (150

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Publication Date
Sun Mar 01 2020
Journal Name
Journal Of Engineering
The effect of titanium oxide microparticles on mechanical properties, absorption and solubility processes of a glass ionomer cement
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Glass Ionomer Cement (GIC) is one of the important dental temporary filing materials. The aim of this study is to evaluate the effect of adding 3, 5 and 7 wt. % of TiO2 microparticles to conventional GIC powder (Riva Self Cure) on mechanical properties and its effect on absorption and solubility processes. TiO2 particles additives improved compressive strength and biaxial flexural strength, where the compressive strength increased with increasing in the added ratio, while the highest value of the biaxial flexural strength was at 3 wt.%. The addition of TiO2 particles improved the surface Vickers microhardness values, with highest value at 5 wt. %. On other hand TiO2 addition im

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Publication Date
Mon Dec 30 2024
Journal Name
Iraqi Journal Of Science
Bio Synthesis, Characterization, and Evaluation of the Anticancer Activity of Gold and Silver Nanoparticles and Their Polyacetal Nanocomposite
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This study synthesized polyacetal from the reaction of polyvinyl alcohol with para-nitrobenzaldehyde. Polyacetal/polyvinylpyrrolidone polymer blends were prepared using solution casting. Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) were biosynthesized using onion peel extract as the reducing agent. Nanocomposites were fabricated by blending polyacetal/PVP with AuNPs and AgNPs at different ratios. XRD and FESEM characterized the AuNPs and AgNPs. FTIR, FESEM, TGA, and DSC characterized the polyacetal, polymer blends, and nanocomposites. DSC and TGA confirmed the improved thermal stability of the polymer blends and nanocomposites. Nanocomposites demonstrated higher efficacy in inhibiting lung cancer cell lines compared t

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Publication Date
Mon Jan 01 2024
Journal Name
Chemical Methodologies
Study of the biological activity and total antioxidant content of complexes derived from sulfonic acid and 4-hydroxybenzaldehyde
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The new liganed Schiff base named [(E)-3-hydroxy-4-((3,4,5- trimethoxybenzylidene)amino) naphthalene-1- sulfonic acid] was synthesized from 3,4,5-trimethoxybenzyldehyde and 1-amino-2-aphthol-4- sulfonic acid in equal molar ratio. A series of new metal complexes' of the common molecular formulation [M(L)2(H2O)2].H2O are synthesized and characterized by IR, UV–Vis spectra, mass spectra, atomic absorption, elemental analyses, chloride content, magnetic susceptibility and conductivity measurements as well as thermo gravimetric analysis (TGA, DSC). Consistent with results of the magnetic and spectral studies, the advised geometrical structures for all of the prepared complexes have been octahedral formula

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