Abstract

One of the most suitable materials to be used in latent heat thermal energy storage system (LHTES) are Phase change materials, but a problem of slow melting and solidification processes made many researchers focusing on how to improve their thermal properties. This experimental work concerned with the enhancing of thermal conductivity of phase change material. The enhancing method was by the addition of copper Lessing rings in phase change material (paraffin wax). The effect of diameter for the used rings was studied by using two different diameters (0.5 cm and 1cm). Also, three volumetric percentages of rings addition (3%, 6% and 10%) were tested for each diameter. The discharging process was done with

    The weak and strong forms are so called because it is not their lexical content that primary matter, but the role they have in the sentence. The problematic confusion, our students encounter, in recognizing and producing the correct pronunciation of weak and strong forms of the English function words is the main incentive behind conducting  this study. In order to gather the data, this paper used two types of tests: a recognition test and a production test. The general results reached  through the analysis of the students' answers seem to conform to the researcher's assumption: students face a critical problem in recognizing and producing correct pronunciation of the weak and strong forms of the English funct

The article states that the Russian verbs of destruction belong to the lexical-semantic group of physical impact. They include verbs with the meaning of “damage” and “destroy”. It is emphasized that each of these groups is relatively independent; the cut line between them is fuzzy and arbitrary. It is postulated that when the object is completely destroyed, then the verb has the meaning of “destruction”,  and when the object is partially destroyed, then the  verb has the meaning of “damage”. It is this feature that individualizes the meaning of verbs. The study distinguishes between the groups and the nature of the object as- animate / inanimate. The object of the action of the “destruction” can only be inan

In this paper, an analytical solution describing the deflection of a cracked beam repaired with piezoelectric patch is introduced. The solution is derived using perturbation method. A novel analytical model to calculate the proper dimensions of piezoelectric patches used to repair cracked beams is also introduced. This model shows that the thickness of the piezoelectric patch depends mainly on the thickness of the cracked beam, the electro-mechanical properties of the patch material, the applied load and the crack location. Furthermore, the model shows that the length of the piezoelectric patches depends on the thickness of the patch as well as it depends on the length of the cracked beam and the crack depth. The additio

In this paper, three types of epoxy-based coatings (Polyamide, pure Polyamine, and Polyamine reinforced by glass-flake) used as a lining for potable water tanks were studied using experimental and finite element methods. Tensile, impact, and fatigue tests were conducted on uncoated and coated AISI 316 stainless steel. The test results show that the applied epoxy based coating improves the mechanical properties, increases of fatigue crack resistance, and enhance the dynamic fracture toughness. The fatigue crack propagation is influenced by the compositions of epoxy coating, and the glass-flake improves the coating resistance to fatigue crack propagation compared to other types.

In this paper, an analytical solution describing the deflection of a cracked beam repaired with piezoelectric patch is introduced. The solution is derived using perturbation method. A novel analytical model to calculate the proper dimensions of piezoelectric patches used to repair cracked beams is also introduced. This model shows that the thickness of the piezoelectric patch depends mainly on the thickness of the cracked beam, the electro-mechanical properties of the patch material, the applied load and the crack location. Furthermore, the model shows that the length of the piezoelectric patches depends on the thickness of the patch as well as it depends on the length of the cracked beam and the crack depth. The additional flexibil

Used cooking oil was undergoing trans-esterification reaction to produce biodiesel fuel. Method of production consisted of pretreatment steps, trans-esterification, separation, washing and drying. Trans-esterification of treated oils was studied at different operation conditions, the methanol to oil mole ratio were 6:1, 8:1, 10:1, and 12:1, at different temperature 30, 40, 50, and 60 ^º C, reaction time 40, 60, 80, and 120 minutes, amount of catalyst 0.5, 1, 1.5, and 2 wt.% based on oil and mixing speed 400 rpm. The maximum yield of biodiesel was 91.68 wt.% for treated oils obtained by trans-esterification reaction with 10:1 methanol to oil mole ratio, 60 ^º C reaction temperature, 80 minute reactio

The ideas and principles formulated by Ibn-Jamaah in the field of education occupy a central place in the historical origins of education for Muslims. These views and principles have an active role in the educational reorganization that the Islamic world aspires to. These ideas have had a great impact on the educational process that had preceded the opinions of Russo, Pestalutzi, Fruel, Herbert, and Dewey. Moreover, we have seen that the Sheikh of Ibn-Jamaah has taken part in formulating the origins of education and leadership.

Objectives: The study aims to: (1) assess psychological distress in parents of autistic children, (2) identify the
relationship between psychological distress and parents' socio-demographic characteristics such as (age, marital
status, relationship with child, educational level and monthly income) and (3) identify the relationship between
parent's distress and some of children' socio-demographic characteristics such as (gender, age, birth order and
mean number of children).
Methodology: A descriptive–analytical study that was carried out from December 12th, 2011 to May 1st, 2012.
on a purposive (non- probability) sample of 120 parents (father and mother) who have children with autism and
send their children to the