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 exp

Numerical investigation has been carried out on heat transfer and friction factor characteristics of copper-water nanofluid flow in a constant heat-fluxed tube with the existence of new configuration of vortex generator using Computational Fluid Dynamics (CFD) simulation. Two types of swirl flow generator: Classical twisted tape (CTT) and Parabolic-cut twisted tape (PCT) with a different twist ratio (y= 2.93, 3.91 and 4.89) and different cut depth (w= 0.5, 1.0 and 1.5 cm) with 2% and 4% volume concentration

The solidification process in a multi-tube latent heat energy system is affected by the natural convection and the arrangement of heat exchanger tubes, which changes the buoyancy effect as well. In the current work, the effect of the arrangement of the tubes in a multi-tube heat exchanger was examined during the solidification process with the focus on the natural convection effects inside the phase change material (PCM). The behavior of the system was numerically analyzed using liquid fraction and energy released, as well as temperature, velocity and streamline profiles for different studied cases. The arrangement of the tubes, considering seven pipes in the symmetrical condition, are assumed at different positions in the system, i

Consequence of thermal and concentration convection on peristaltic pumping of hyperbolic tangent nanofluid in a non‐uniform channel and induced magnetic field is discussed in this article. The brief mathematical modeling, along with induced magnetic field, of hyperbolic tangent nanofluid is given. The governing equations are reduced to dimensionless form by using appropriate transformations. Exact solutions are calculated for temperature, nanoparticle volume fraction, and concentration. Numerical technique is manipulated to solve the highly non‐linear differential equations. The roll of different variables is graphically analyzed in terms of concentration, temperature, volume fraction of nanoparticles, axial induced magnetic fie

The researcher in the history of the Arab-Islamic state finds that the emirate of Hajj took a large part of the care of the caliphs - because it was linked to the Islamic religion. In addition to its political dimension, it is a symbol of the strength of political authority.. Therefore, you must get the study and research you deserve During the era of the Abbasid Caliph Musa al-Hadi, we find that this emirate coincided with a historical event,( waqieat fakh) , whose future consequences had an impact on the map of the Islamic world, with the emergence of (Al-adarsa) state in the Islamic Maghreb.

Objectives: The aim of the study is to evaluate the information of caregivers concerned emergency care for the elderly and to identify the relationship between caregiver information and their educational level, years of service and training courses. Methodology: A quasi-experimental study was conducted in the Geriatric Care Home in Baghdad City (the governmental and private geriatric care home ) for the period from October, 14th , 2018 to March, 20th , 2019 to find the effectiveness of the instructional program on caregivers knowledge about emergency care for the elderly.. A purposive sample (non-probability) was consisting of (30) males and females caregivers, the sample was selected from geriatric care home in Baghdad city .To implemen