Background: The ideal force-delivery system must: provide optimal tooth moving forces that elicit the desired effects, be comfortable and hygienic for the patient, require minimal operator manipulation and patient cooperation and provide rapid tooth movement with minimal mobility during orthodontic therapy, the elastomeric chains have the greatest potential to fulfill these requirements. Materials and Methods: This in vitro study was designed to determine the effect of three different mechanisms for canine retraction : (6-3 , 6-5-3 and chain loop ) on the load relaxation behavior of three types of elastomeric chains : (maximum clear , maximum silver and extreme silver) from the same company (Ortho Technology company) with two different bran

An oil spillage has been a great threat to human life in parts of Koya district, especially through the contamination of domestic water. An attempt was made to find and map the extent of pollution in the area. According to a field survey, more than 17 springs and 34 hand-dug and artesian wells have been contaminated with crude oil. The contamination was recorded recently after loading began of tens of oil tankers in the Taq-Taq oil field, and as a result hundred barrels of oil have spilled into the creeks and soil daily. Hence, 2D resistivity imaging was adopted via four laid-out traverses running normal to the strike of the outcrops. A Wenner-Schlumberger array configuration was used to achieve both vertical and lateral resistivity dist

In this paper, a FPGA model of intelligent traffic light system with power saving was built. The intelligent traffic light system consists of sensors placed on the side's ends of the intersection to sense the presence or absence of vehicles. This system reduces the waiting time when the traffic light is red, through the transition from traffic light state to the other state, when the first state spends a lot of time, because there are no more vehicles. The proposed system is built using VHDL, simulated using Xilinx ISE 9.2i package, and implemented using Spartan-3A XC3S700A FPGA kit. Implementation and Simulation behavioral model results show that the proposed intelligent traffic light system model satisfies the specified operational req

The pollution of aquatic ecosystems with toxic heavy metals is representing a major environmental issue, as a result of releasing these metals to ecological ambient without treatment, leading to their persistence and non-biodegradation in the environment. Various traditional methods are utilized as an attempt to remove heavy metals from waste water but still without making any actual progress. This study hypothesizes that Eichhornia crassipes (water hyacinth) dried leaves powder is potential in removing some of these heavy metals (HM), including lead, copper, cadmium and chrome from aqueous solutions via biosorption influenced by some variable experimental factors. This aim was approached by using two different experimental conditions: (

This work presents the construction of a test apparatus for air-conditioning application that is flexible in changing a scaled down adsorbent bed modules. To improve the heat and mass transfer performance of the adsorbent bed, a finned-tube of the adsorbent bed heat exchanger was used. The results show that the specific cooling power (SCP) and the coefficient of performance (COP) are 163 W/kg and 0.16, respectively, when the cycle time is 40 min, the hot water temperature is 90^oC, the cooling water temperature is 30^oC and the evaporative water temperature is 11.4^oC.

In this paper, a new procedure is introduced to estimate the solution for the three-point boundary value problem which is instituted on the use of Morgan-Voyce polynomial. In the beginning, Morgan-Voyce polynomial along with their important properties is introduced. Next, this polynomial with aid of the collocation method utilized to modify the differential equation with boundary conditions to the algebraic system. Finally, the examples approve the validity and accuracy of the proposed method.

Aspergillus niger is one of the most important filamentous fungi that used in the fermentation industry. Aspergillus niger isolate was cultured on potato-dextrose agar (PDA) for activation, and the optimum conditions for xylanase production from this local isolate were studied by solid state fermentation, using a medium composed of wheat bran moisten with corn steep liquor at ratio 1:0.5 (v:w) at initial pH 5.5, inoc-ulated with 1.6 × 106 spores/ml, and incubated at 30ᵒC for 5 days.

The transition from low Earth orbit 200-1500 (km) to geostationary Earth orbit 42162 (km) was studied in this work by many methods of transfer. The delta-v requirement (Δv), the time of flight (Δt), the mass ratio of propellant consume (Δm/m) and total mass was calculated for many values altitude in the same plane also when the plane is change. The results from work show that (Δv) that required for transfer when the plane of orbit change is large than (Δv) required when the transfer in coplanar maneuvers while the bi-elliptical transfer method need time of transfer longer than a Hohmann transfer method. The most energy efficiency was determined when the transfer in coaxial between elliptical orbits

This Action research aimed at Assisting Students of Faculty of Educational Sciences  at Al-Quds Open University to design computerized  lessons using the Power Point software and according to ADDIE model. The study sample consisted of 40 students  who were taking a course titled Technology of Education during the second semester of the 2014-2015 academic year and three academic instructors . To collect the required date  , the researchers used  focus group technique and structured interviews to get information from the 40 students and the three academic instructors involved in the course Technology of Education in QOU /Nablus Branch. In addition to these methods, a workshop with a guiding checklist was employed t

This work includs synthesis of several Schiff bases by condensation of 6- methoxy – 2- amino benzothiazole with some aldehydes and ketones (2- hydroxyl benzaldehyde, 4- hydroxyl benzaldehyde, 4- N,N –dimethy amino acetophenone, benzophenone) to abtain schiff bases (1-5). These schiff bases were found to react with phthalate anhydride to give oxazepine derivatives (6-10) that were reacted with primary aromatic amines to give Diazepine derivatives (11-15). Besides, we prepared new tetrazole derivatives (16-20) from the reaction of the prepared Schiff bases with sodium azide in the prepared compounds that were characterized by physical properties, FT-IR and some of the 1H-NMR and 13C –NMR spectroscopy.