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Design High Efficient Reflectivity of Distributed Bragg Reflectors
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Bragg Reflectors consist of periodic dielectric layers having an optical path length of quarter wavelength for each layer giving them important properties and makes them suitable for optoelectronics applications. The reflectivity can be increased by increasing the number of layers of the mirror to get the required value. For example for an 8 layers Bragg mirror (two layers for each dielectric pair), the contrast of the refractive index has to be equal to 0.275 for reaching reflectivity > 99%. Doubling the number of layers results in a reflectivity of 99.99%. The high reflectivity is purely caused by multiple-interference effects. It can be analyzed by using different matrix methods such as the transfer matrix method (TMM) which is the simplest method to study the characteristic of devices with different alternating layers.

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Publication Date
Tue Dec 15 2020
Journal Name
Al-academy
Sound Structure and Attraction Effectiveness in Graphic Design Field: منير جباري علي
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      What concerns the research is employing the modern technology  in a compatible way, because it has multiplied  with the visual  working functions and has grown  in a special way with the development of the digital graphic design field  which represents a crystallization  product according  to  investigation and experimentation mechanism within the field of the scientific research  in the design field and development of the skills of the first designing worker, who always seeks to find working and functional structures in order to produce a design  with a clear meaning by utilizing the technological  abilities including the acoustic tech

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Crossref
Publication Date
Wed Mar 29 2023
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Multi-Stage Hydraulic Fracturing Completion Design Based on Ball-and-Sleeve Method
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This paper proposes a completion that can allow fracturing four zones in a single trip in the well called “Y” (for confidential reasons) of the field named “X” (for confidential reasons). The steps to design a well completion for multiple fracturing are first to select the best completion method then the required equipment and the materials that it is made of. After that, the completion schematic must be drawn by using Power Draw in this case, and the summary installation procedures explained. The data used to design the completion are the well trajectory, the reservoir data (including temperature, pressure and fluid properties), the production and injection strategy. The results suggest that multi-stage hydraulic fracturing can

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Crossref
Publication Date
Mon Apr 02 2018
Journal Name
Al-nahrain Journal For Engineering Sciences (njes)
Output Feedback Adaptive Sliding Mode Control Design for a Plate Heat Exchanger
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The heat exchanger is a device used to transfer heat energy between two fluids, hot and cold. In this work, an output feedback adaptive sliding mode controller is designed to control the temperature of the outlet cold water for plate heat exchanger. The measurement of the outlet cold temperature is the only information required. Hence, a sliding mode differentiator was designed to estimate the time derivative of outlet hot water temperature, which it is needed for constructing a sliding variable. The discontinuous gain value of the sliding mode controller is adapted according to a certain adaptation law. Two constraints which imposed on the volumetric flow rate of outlet cold (control input) were considered within the rules of the proposed

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Publication Date
Tue Sep 21 2021
Journal Name
Jmerd
stress and strain analysis for the prosthetic hand design actuated by links
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Prosthetic hands are compensatory devices for the hand amputees as a result of injury, various accidents or birth deformities, types of prosthetic hand vary depending on the mechanism they operate and how they perform. There are common types in use that are characterized by their complex mechanisms, which are difficult for the amputee to use or exclude use because of their high cost, therefore the aim of this research is to design an artificial hand that is suitable in terms of simplicity of use and low cost and similar to a natural hand with regard to dimensions and shape that operated in the mechanism of links. This research involves Stress and strain analysis of the prosthetic hand and its fingers that modelled from (Petg CR)

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Publication Date
Mon Apr 02 2018
Journal Name
Al-nahrain Journal For Engineering Sciences (njes)
Output Feedback Adaptive Sliding Mode Control Design for a Plate Heat Exchanger
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The heat exchanger is a device used to transfer heat energy between two fluids, hot and cold. In this work, an output feedback adaptive sliding mode controller is designed to control the temperature of the outlet cold water for plate heat exchanger. The measurement of the outlet cold temperature is the only information required. Hence, a sliding mode differentiator was designed to estimate the time derivative of outlet hot water temperature, which it is needed for constructing a sliding variable. The discontinuous gain value of the sliding mode controller is adapted according to a certain adaptation law. Two constraints which imposed on the volumetric flow rate of outlet cold (control input) were considered within the rules of the proposed

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Publication Date
Tue May 01 2018
Journal Name
Journal Of Engineering Science And Technology
A proposed dual size design for energy minimization in sub-threshold circuits
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Sub-threshold operation has received a lot of attention in limited performance applications.However, energy optimization of sub-threshold circuits should be performed with the concern of the performance limitation of such circuit. In this paper, a dual size design is proposed for energy minimization of sub-threshold CMOS circuits. The optimal downsizing factor is determined and assigned for some gates on the off-critical paths to minimize the energy at the maximum allowable performance. This assignment is performed using the proposed slack based genetic algorithm which is a heuristic-mixed evolutionary algorithm. Some gates are heuristically assigned to the original and the downsized design based on their slack time determined by static tim

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Scopus
Publication Date
Sun Sep 05 2010
Journal Name
Baghdad Science Journal
Design and Implementation for optical fiber communication system using frequency shift coding
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In this research, optical communication coding systems are designed and constructed by utilizing Frequency Shift Code (FSC) technique. Calculations of the system quality represented by signal to noise ratio (S/N), Bit Error Rate (BER),and Power budget are done. In FSC system, the data of Nonreturn- to–zero (NRZ ) with bit rate at 190 kb/s was entered into FSC encoder circuit in transmitter unit. This data modulates the laser source HFCT-5205 with wavelength at 1310 nm by Intensity Modulation (IM) method, then this data is transferred through Single Mode (SM) optical fiber. The recovery of the NRZ is achieved using decoder circuit in receiver unit. The calculations of BER and S/N for FSC system a

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Crossref
Publication Date
Tue Aug 15 2023
Journal Name
Al-academy
Sustainable design in the Iraqi craft industries and ways to develop them
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Research on sustainable design in Iraqi craft industries and ways to develop them is essential to preserving the cultural heritage and authenticity of these industries while promoting environmentally sustainable practices. Lack of access to modern technologies, knowledge and resources may hinder the growth of these industries and their ability to compete in the global market. The research problem revolves around finding ways to develop sustainable design in the Iraqi craft industries. The expected outcomes of this research include a clear definition of sustainable design, understanding the history of sustainable design in the craft industry, identifying different types of craft industries in Iraq, exploring the basic concepts of sustaina

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Crossref
Publication Date
Wed Jul 01 2020
Journal Name
Journal Of Engineering
Bat Algorithm Based an Adaptive PID Controller Design for Buck Converter Model
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The aim of this paper is to design a PID controller based on an on-line tuning bat optimization algorithm for the step-down DC/DC buck converter system which is used in the battery operation of the mobile applications. In this paper, the bat optimization algorithm has been utilized to obtain the optimal parameters of the PID controller as a simple and fast on-line tuning technique to get the best control action for the system. The simulation results using (Matlab Package) show the robustness and the effectiveness of the proposed control system in terms of obtaining a suitable voltage control action as a smooth and unsaturated state of the buck converter input voltage of ( ) volt that will stabilize the buck converter sys

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Crossref
Publication Date
Wed Mar 01 2023
Journal Name
Results In Engineering
Low-cost autonomous car level 2: Design and implementation for conventional vehicles
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