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Resistance of bonded premolars to four artificial ageing models post enamel conditioning with a novel calcium-phosphate paste
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Background: This in vitro study compares a novel calcium-phosphate etchant paste to conventional 37% phosphoric acid gel for bonding metal and ceramic brackets by evaluating the shear bond strength, remnant adhesive and enamel damage following water storage, acid challenge and fatigue loading. Material and Methods: Metal and ceramic brackets were bonded to 240 extracted human premolars using two enamel conditioning protocols: conventional 37% phosphoric acid (PA) gel (control), and an acidic calcium-phosphate (CaP) paste. The CaP paste was prepared from β-tricalcium phosphate and monocalcium phosphate monohydrate powders mixed with 37% phosphoric acid solution, and the resulting phase was confirmed using FTIR. The bonded premolars were exposed to four artificial ageing models to examine the shear bond strength (SBS), adhesive remnant index (ARI score), with stereomicroscopic evaluation of enamel damage. Results: Metal and ceramic control subgroups yielded significantly higher (p ˂ 0.05) SBS (17.1-31.8 MPa) than the CaP subgroups (11.4-23.8 MPa) post all artificial ageing protocols, coupled with higher ARI scores and evidence of enamel damage. In contrast, the CaP subgroups survived all artificial ageing tests by maintaining adequate SBS for clinical performance, with the advantages of leaving unblemished enamel surface and bracket failures at the enamel-adhesive interface. Conclusions: Enamel conditioning with acidic CaP pastes attained adequate bond strengths with no or minimal adhesive residue and enamel damage, suggesting a suitable alternative to the conventional PA gel for orthodontic bonding.

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Publication Date
Sun Feb 03 2019
Journal Name
Iraqi Journal Of Physics
Compressive strength measurement for cement replacement with recycled glass in concrete
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The most important environmental constraints at the present time
is the accumulation of glass waste (transparent glass bottles). A lot of
experiments and research have been made on waste and recycling
glass to get use it as much as possible. This research using recycling
of locally waste colorless glass to turn them into raw materials as
alternative of certain percentages of cement to save the environment
from glass waste and reduce some of the disadvantages of cement
with conserving the mechanical and physical properties of concrete
made. A set of required samples were prepared for mechanical test
with different weight percentage of waste glass (2%, 4%, 5%, 6%,
8%, 10%, 15%, 20% and 25%). American standard

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Publication Date
Tue Nov 15 2022
Journal Name
Association Of Arab Universities Journal Of Engineering Sciences
A-mechanical properties of engineered cementitious composite concrete produced from Portland limestone cement
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Conventional concretes are almost unbending, and even a small amount of strain potential leaves them brittle. This lack of bendability is a major source of strain loss, and it has been the main goal behind the development of bendable concrete, often known with engineered ce ment composites, or ECC. This form of concrete has a lot more flexibility than regular concrete. Micromechanical polymer fibers are used to strengthen ECC. In most cases, ECC uses a 2% amount of thin, separated fibers. As a result, bendable concrete deforms but unlike traditional concrete, it does not crack. This study aims to include this kind of concrete, bendable concrete, which can be used to solve concrete problems. Karasta (CK) and Tasluja (CT) Portland Lime

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Publication Date
Sat Aug 01 2020
Journal Name
Journal Of Engineering
Computation of Critical Submergence Depth to Avoid Surface Vortices at Vertical Pumps Intakes
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The pumping station became widely used in many fields. Free surface vortices at intakes of pumps are not favorable. It may cause noise, excessive vibration, damage to the pumping structure, reduction in efficiency and flow for hydro-turbines, etc. One of the important problems encountered during the pump intake design is the depth of submergence and other design parameters to avoid strong free-surface vortices formation. This study aims to compute the critical submergence depth with some geometrical and hydraulic limitations by using Computational Fluid Dynamic (CFD) package. The mathematical model was validated with a laboratory model that had been conducted. The model of three intake pipes was investigated under five d

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Publication Date
Sun Mar 02 2008
Journal Name
Baghdad Science Journal
Calculations of Signal to Noise Ratio (SNR) for Free Space Optical Communication Systems
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In this paper, we calculate and measure the SNR theoretically and experimental for digital full duplex optical communication systems for different ranges in free space, the system consists of transmitter and receiver in each side. The semiconductor laser (pointer) was used as a carrier wave in free space with the specification is 5mW power and 650nm wavelength. The type of optical detector was used a PIN with area 1mm2 and responsively 0.4A/W for this wavelength. The results show a high quality optical communication system for different range from (300-1300)m with different bit rat (60-140)kbit/sec is achieved with best values of the signal to noise ratio (SNR).

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Publication Date
Tue Aug 15 2023
Journal Name
Al-academy
Reading the visual discourse according to the design structures of the internal environments
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The current research dealt with contrastive structures and the culture of reception in the design of interior spaces as embodying a rhetorical aspect that reveals formal values related to the meanings of beauty through the mechanisms of symbolism and interpretation that drives mental behavior and is in harmony with intellectual data and its performance function.
Hence, the research in the first chapter dealt with the research problem, the need for it, and the extent of the necessity that calls for studying contrastive structures in interior design and architecture, and touching and searching for what is the paradox and its representations for the recipient, in which the interior designer plays an active role in presenting the best cre

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Publication Date
Sun Sep 01 2019
Journal Name
10.31272/jeasd.23.5.9
EVALUATION OF HOT MIX ASPHALT CONTAINING RECLAIMED ASPHALT PAVEMENT TO RESIST MOISTURE DAMAGE
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Due to increasing cost of asphalt binder, significant economic savings can be realized by using the amount from reclaimed asphalt pavement (RAP) in the production of new hot mix asphalt (HMA). Moreover, this is an environmentally friendly option as it reduces the demand for virgin materials. It has to be remarked that in Iraq RAP is not used in the production of HMA and this valuable material is mostly degraded for use in lower value applications. Four mixtures were designed, which contains three different percent RAP, it is (0%, 5%, 15%) with asphalt grade (40-50) and (25%) with asphalt grade (60-70), it has been changed the grade of asphalt when adding RAP (25%) to compensate for the aged binder in the RAP when adding to mixture. All type

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Publication Date
Thu Nov 01 2012
Journal Name
Iraqi Journal Of Science
THE EVOLUTION OF PLANETARY NEBULAE(PN) AND FADING TIME ACCORDING TO SYNTHETIC MODEL
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Abstract Planetary nebulae (PN) represents the short phase in the life of stars with masses (0.89-7) M☉. Several physical processes taking place during the red giant phase of low and intermediates-mass stars. These processes include :1) The regular (early ) wind and the envelope ejection, 2) The thermal pulses during Asymptotic Giant Branch (AGB ) phase. In this paper it is briefly discussed how such processes affect the mass range of Planetary Nebulae(PN) nuclei(core) and their evolution, and the PN life time, and fading time for the masses which adopted. The Synthetic model is adopted. The envelope mass of star (MeN ) and transition time (ttr) calculated respectively for the parameter (MeR =1.5,2, 3×10-3 M☉). Another time scale is o

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Publication Date
Wed Mar 15 2023
Journal Name
Al-academy
Design requirements according to the formal integration in the design of interior spaces
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The formal integration of the interior spaces in general and the commercial spaces of the watch shops in the large commercial centers in particular is the goal that the designers aim to reach in order for the interior space to become successful in terms of the design idea and its characteristics. Implementation mechanism. One of the reasons for achieving formal integration in the interior spaces of watch shops is the requirements of the design that must be available in these spaces to reach a state of formal integration between the interior and the exterior so that the space becomes fully integrated in all respects. Because of the aforementioned reasons for dealing with the research, through four chapters: The first chapter included the

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Publication Date
Mon Oct 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
Investment in Human Resources According to the Requirements of Work Markets in Iraq
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Investment in Human is one of the best and most important investments as it is renewed and developed resource over time in comparison with depleted material resources. Human resources is considered the part of the population that could be employed economically to contribute in increasing production energies as it is the support pillar of the society and have great energies that construct the society and raise of nations as well as he is distinguished with characteristics of ambitions to freedom.

Iraq is one of the countries that has large number of population in age of work and production and reduce in age dependent classes (children and old people).This dynamic in population led to step

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Publication Date
Tue Dec 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
Achieve the requirements of the Administrative Control according to human resource management practices
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Human Resources Management Practices (HRMP) and managerial control represent two academic fields that have been and still are the focus of many studies. However, merging both fields and studying the relationship that connects them and also the role that HRMP play in achieving the requirements of managerial control represents a new and novel study according to the available literature in these fields.

To achieve these goals, this study has been conducted, using the surveying questionnaire method, on a sample of ten general inspector offices in Iraq that work in the field of control for ministries and independent committees. A questionnaire has been used to collect the data which was analyzed with several s

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