The migration from IPv4 to IPv6 can not be achieved in a brief period, thus both protocols co-exist at certain years. IETF Next Generation Transition Working Group (NGtrans) developed IPv4/IPv6 transition mechanisms. Since Iraq infrastructure, including universities, companies and institutions still use IPv4 protocol only. This research article tries to highlight, discuss a required transition roadmap and extend the local knowledge and practice on IPv6. Also, it introduces a prototype model using Packet tracer (network simulator) deployed for the design and implementation of IPv6 migration. Finally, it compares and evaluates the performance of IPv6, IPv4 and dual stack using OPNET based on QoS metrics such as throughput, delay and point to point utilization the key performance metrics for network with address allocation and router configuration supported by Open Shortest Path First (OSPF) routing protocol. In addition it compares dual-stack to the tunneling mechanism of IPv6 transition using OPNET. The results have shown that IPv6 network produces a higher in throughput, response time and Ethernet delay, but little difference in packet dropped, additionally the result in TCP delay, Point to point utilization shows small values compared to dual-stack networks. The worst performance is noted when 6 to 4 tunneling is used, tunneling network produces a higher delay than other scenarios.
A new two-way nesting technique is presented for a multiple nested-grid ocean modelling system. The new technique uses explicit center finite difference and leapfrog schemes to exchange information between the different subcomponents of the nested-grid system. The performance of the different nesting techniques is compared, using two independent nested-grid modelling systems. In this paper, a new nesting algorithm is described and some preliminary results are demonstrated. The validity of the nesting method is shown in some problems for the depth averaged of 2D linear shallow water equation.
The efficiency of internal combustion engines (ICE) is usually about thirty percent of the total energy of the fuel. The residual energy is lost in the exhaust gas, the lubrication, and the cooling water in the radiators. Recently much of the researcher’s efforts have focused on taking advantage of wasted energy of the exhaust gas. Using a thermoelectric generator (TEG) is one of the promising ways. However, TEG depends entirely on the temperature difference, which may be offered by the exhaust muffler. An experimental test has been conducted to study the thermal performance of a different muffler internal design. The researchers resort to the use of lost energy in an ICE using TEG, which is one of the ways to take adv
... Show MoreA free convective heat transfer from the inside surface of a uniformly heated vertical circular tube has been experimentally investigated under a constant wall heat flux boundary condition for laminar air flow in the ranges of RaL from 6.9108 to 5109. The effect of the different sections (restrictions) lengths placed at the exit of the heated tube on the surface temperature distribution, the local and average heat transfer coefficients were examined. The experimental apparatus consists of aluminum circular tube with 900 mm length and 30 mm inside diameter (L/D=30). The exit sections (restrictions) were included circular tubes having the same inside diameter as the heated tube but with different lengths of
... Show MoreThe importance of evaluation depends on many institutions, whether governmental or private, including media institutions, rely on the list to evaluate the weight of things and appreciation, as well as judging things, achievements, and everything related to the institution is concerned. Because through evaluation, institutions can recognize weaknesses and strengths. It is also an effective tool for management review, through which the institution can review everything related to planning and decision-making, leadership, incentives and other administrative matters.
Therefore, this study attempts to shed light on the evaluation process, its basics and its importance in general and in the Kurdish media institutions as a model in part
... Show MoreBackground: The purpose of the current study was to evaluate the efficacy of a new orthodontic bonding system (Beauty Ortho Bond) involving the shear bond strength in dry and wet environments, and adhesion remnant index (ARI) scores evaluation in regard to other bonding systems (Heliosit and Resilience Orthodontic Adhesives). Materials and methods: Sixty defect free extracted premolars were randomly divided into six groups of 10 teeth each, mounted in acrylic resin, three groups for a dry environment and three for a wet one. Shear bond strength test was performed with a cross head speed of 0.5 mm/min, while surfaces of enamel and bracket-adhesive-enamel surfaces were examined with stereomicroscope For ARI scores evaluation. Data were analyz
... Show MoreThe study aims to follow modern methods in teaching rhythmic gymnastics skills by directing learners to develop their perceptions and absorb what the world deals with today and develop intelligence among learners, the researchers searched for the strengths of the learner by providing them with an opportunity to form their kinetic formation, hence the problem came by introducing a method of self-intelligence and social to guide the learner in the search for ways and solutions to overcome boredom and economy Time and effort in the educational process in learning and give them the freedom to express their ideas And their skills and here came the role of social and self-intelligence to teach the individual and collective kinetic formati
... Show MoreConsistent "with the thought of tax talk is unified tax natural evolution for him, as the application leads to the inclusion of tax all branches of income and its sources and through truncated part of this entry through the application of price ascending it, it means the procedures of tax reform. Taxes on total income characterized by giving a clear picture of the total income of the taxpayer and its financial situation and its burden family which allows granting exemptions, downloads, and application of prices that fit this case. This requires reconsideration of the structure of the tax system in force and the transition from a system specific taxes to the tax system on the total income of the integration of income from the rental of re
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