البحث — المستودع الرقمي العراقي

المستخلص: التقنية الواعدة التي تستخدم لتعزيز عملية الانتقال الحراري هي باستخدام الموائع النانوية كخيار جيد واستبدالها محل السوائل التقليدية الشائعة. والمبادلات الحرارية هي معدات واسعة التطبيق في كثير من التطبيقات الصناعية المختلفة وبالتالي يكون سلوك وخصائص المائع | The most promising technique that is used to enhance the thermal performance for the heat transfer processes is using the nanofluids as a good choice to replace the conventional fluids. The heat exchangers are the wide range application equipment that is used for different industrial applications and therefore, the properties and the behavior of the fluid media are the main control parameters in equipment design of the heat exchangers. In this work an attempt was made to investigate experimentally the thermal performance of nanofluid which consists of deionized water (DI) as a base fluid and Aluminum oxide (Al2O3) as solid nanoparticles. The investigation includes two parts, the first one is studying the effect of addition of solid nanoparticles to the base fluid on the thermo - physical properties such as density, viscosity and thermal conductivity for different values of the volume fraction of nanoparticles. The second part includes the experimental work studying the effect of the nanoparticles (Al2O3) volume fraction (0.05, 0.1 with base fluid ), heat flux (With three values 7.4W,11W,16.8W) and angle (With two values 90?,45?) with four models (four different type from wicks in heat pipe) to enhance the heat transfer in heat pipe with two cases of transient temperature distribution and steady state. One model is different from the other by using different wicks in a heat pipe in all models. The general results referred to the enhancement of heat transfer rate are represented by increasing the concentration of nanoparticles (Al2O3) volume fraction such as (?=0.1) is better than (?=0, ?=0.05), increasing heat flux such as (16.8W) is better than (7.4W,11W) and an inclination angle such as( 45?) is better than (90?).At the transient state the time to reach to the steady state decreases when the concentration of the nanoparticles (Al2O3) volume fraction increases, the heat flux increases and the angle incline. In model 4 the heat transfer enhancement is better than that of model 3 and model 3 is better than that of model 2 and model 2 is better than that of model 1.The time to reach the steady state decreases in model 4 more than model 3, model 2 and model 1. The temperature decreases in the heat pipe when we gradually sidle from heater. The time to reach to steady state found in model 4 at concentration of nanofluid (?=0.1) and heat flux (16.8W) in angle (45?) is (19 min). In the steady state when we increase the concentration of the nanoparticles (Al2O3) volume fraction at the same distance (z) the temperature increases ,The increase in the heat flux of the hot part of the heat pipe will always increase the temperature in the heat pipe and the temperatures distribution in the heat pipe will be improved. The thermal performance of the heat pipe is enhanced by increasing the concentration of the nanofluid , the heat flux and by inclining the heat pipe from 90? angle to 45? angle such as in result of model 4.

الصفحات الاولى:

مكان الجامعة: بابل

اللغة: الانكليزية

الجامعة: جامعة بابل - كلية الهندسة - قسم الهندسة الكيمياوية

الدرجة: ماجستير

الموضوع الدقيق: الهندسة الكهروكيمياوية

السنة: 2017

الموضوع العام: الهندسة الكيمياوية

اسم المشرف: تحسين علي الحطاب

اسم المؤلف: شهد فالح حسن

تصميم تقسيم مساحة نظام الارسال الضوئي لنظم الاتصالات Design And Implementation Of Optical Space Division Multiplexer For Tera (B/S) Communication Systems

المستخلص: اتصالات الالياف البصرية هي العمود الفقري للبنية التحتية للاتصالات السلكية واللاسلكية التي تدعم شبكة الانترنت. النظام الاحادي الالياف المستخدم لنقل البينات لم يعد يلبي طلب الحصول على القدرة العالية والمتنامية بشكل مستمر. هناك العديد من الطرق الممكنة لزياد | Optical fiber communication system is considered as the backbone for the infrastructure of telecommunications that handles the internet. The exponentially growing capacity is no longer satisfied by using transmission of single mode fiber. There are several possible methods for increasing transmission capacity over fixed bandwidth. These include mix many signals with optical - carrier onto a one optical fiber by achieving various wavelengths, modulation employing different amplitude levels, and two orthogonal subcarriers and polarization. An extra dimension that a fiber can offer for achieving more information is space.This project demonstrates simulation systems for Space Division Multiplexing (SDM) transmission system using Few - Mode Fiber (FMF). Polarization division multiplexing (PDM) and Dense Wavelength Division Multiplexing (DWDM) techniques are also used in this system to increase total system data rate. For the ultra - high capacity need of SDM, Few Mode Fiber (FMF) was proposed as SDM best technology for obtaining ultra - high bit rate systems with long haul transmission. Inter - mode losses that appears in higher - order - modes was the most problem to be resolved. In this thesis, the description and design of three SDM systems were explored by using both QPSK and 16QAM modulation formats : single channel SDM system with PDM technique, 8 - DWDM channels over 7 modes SDM/PDM system, and 16 - DWDM channels over 10 modes SDM/PDM system proposed as future of ultra - high capacity optical system.By using 16QAM format and bit rate per channel of 40Gb/s, the maximum long reach of our designed single channel SDM/PDM system is 1020Km. A transmission reach of 760Km was achieved for 8 - WDM - 7modes - SDM/PDM system and 260 Km for 16DWDM - 10modes - SDM/PDM. At QPSK modulation format the maximum demonstrated reach was 1460 Km for single channel SDM/PDM system. A long - haul transmission of 1080 Km was recorded for 8 - WDM channels - 7modes - SDM/PDM system and 510 Km for 16 - DWDM channels - 10modes - SDM/PDM system.The total bit rate of single channel - 3modes SDM/PDM system was 240G/s at 40Gb/s bit rate per channel. The total bit rate was achieved by using 8 - DWDM channels - 7modes SDM/PDM system is 4.48 Tb/s at 40Gb/s. The highest bit rate was achieved by using 16DWDMchannels - 10modes SDM/PDM system so that the total achieved bit rate is nearly 12.8Tb/s.Chromatic Dispersion (CD) compensator using Digital Signal Processing (DSP) was proposed to compensate chromatic dispersion losses. Frequency and phase estimators were proposed in the designed systems to remove frequency offset and phase change by using Viterbi and Viterbi algorithms.Adaptive MIMO equalizer using constant modulus algorithms was proposed to compensate deferential group delay, polarization mode dispersion, and other losses simultaneously. Numerical results demonstrated that the methods are very effective in compensating the narrow band filtering and are very robust to channel estimation noise.The demonstrated systems were designed and tested by using (VPI transmission maker v.9.5) powerful software package.SDM techniques provided us with an important source to obtain more system flexibility, scalability, and capacity.

الصفحات الاولى:

مكان الجامعة: بابل

اللغة: الانكليزية

الجامعة: جامعة بابل - كلية الهندسة - قسم الهندسة الكهربائية

الدرجة: ماجستير

الموضوع الدقيق: هندسة الالكترونيك والاتصالات

السنة: 2017

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

اسم المشرف: ابراهيم عبد الله حمزة الشمري

اسم المؤلف: مصدق ماهر عبد الزهرة

تصميم مضاعف تناظري خطي محسن بنطاق واسع يعمل باربعة ارباع Design Of Improved Wideband Linear Four Quadrant Analog Multiplier

المستخلص: استخدمت المضاعفات التناظرية على نطاق واسع في دوائر الاتصالات والشبكات العصبية ككاشفات للطور ومضاعفات للتردد ودوائر لمزج الاشارات والتضمين وفك التضمين. في التطبيقات التقليدية مثل دوائرالتضمين تعتبر ترددات التشغيل والسلوك الخطي للانظمة والمديات المسموح بها | Analog multipliers have been widely exploited in communication circuitries, phase detectors, neural networks, frequency multipliers, mixers, and modulation and demodulation circuits. In conventional applications, such as modulation circuits, the linearity, frequency of operation, and input voltage ranges are issues of great importance for multipliers. This work targeted these issues through the design of two types of four quadrant analog multipliers operating in wideband frequency ranges and having very high linearity with input and output voltage ranges of ±10V.The first wideband four - quadrant analog multiplier is designed using wideband squaring and operational amplifier (OPAMP) circuits. The wideband OPAMP is designed using 10 NMOS transistors based on 0.35 µm NMOS technology with supply voltages of ?12V. The wideband OPAMP has exhibited an open loop voltage gain of 3336545. The squaring circuit is built using two NMOS transistors and two wideband OPAMPs. The first wideband multiplier is built using two identical squaring circuits, two difference amplifiers, and one summing amplifier. It is characterized by high input - output linearity range of - 10 V to +10 V for both inputs, ±10 V input and output voltage ranges, and cutoff frequency of about 5 GHz. The second wideband four quadrant analog multiplier is designed using NPN bipolar junction transistors. It is built with two main circuits, which are the multiplier cell and the output circuit. The multiplier cell is built using a modified Gilbert multiplier, while the output circuit is a high gain circuit designed for changing the differential output of the multiplier cell to a single output having a voltage range of ±10 V. The multiplier circuit is designed with supply voltages of ?12 V. It is characterized by high input - output linearity range of - 10 V to +10 V for both inputs, ±10 V input and output voltage ranges, and cutoff frequency of about 1 GHz.Both multipliers are designed and tested on PSpice in ORCAD / Version 16.6.

الصفحات الاولى:

مكان الجامعة: بابل

اللغة: الانكليزية

الجامعة: جامعة بابل - كلية الهندسة - قسم الهندسة الكهربائية

الدرجة: ماجستير

الموضوع الدقيق: هندسة الالكترونيك والاتصالات

السنة: 2017

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

اسم المشرف: عبد الكريم مخيف عبيس

اسم المؤلف: رسل صلاح خضير