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تحليل خطاب نقدي للمناظرات الرئاسية لانتخابات 2012 الامريكية == A Critical Discourse Analysis Of The 2012 American Presidential Election Debates

اسم المؤلف: محمد سامي فليفل الاسدي
اسم المشرف: منذر منهل محمد الدليمي
الموضوع العام: اللغات الاجنبية
السنة: 2014
الموضوع الدقيق: الانكليزية - اللغة
الدرجة: ماجستير
الجامعة: جامعة بغداد
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:

تصميم وتنفيذ منظومة محادثة باستخدام مفاهيم امنية الشبكات == Design and implementation of conversation system using network security concepts

اسم المؤلف: ميساء عبد الخالق عطية
اسم المشرف: بشار مكي نعمة العيساوي
الموضوع العام: علوم الحاسبات
السنة: 2014
الموضوع الدقيق: علوم الحاسبات
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: تصميم وتنفيذ منظومة محادثة باستخدام مفاهيم امنية الشبكات"اصبحت انظمة المحادثة والتواصل الاجتماعي امرا حيويا وفعالا لايمكن الاستغناء عنه في مختلف ميادين الحياة اليومية .تتميز هذه الانظمة بصفة رئيسية وهي ان المحادثة تكون بشكل اني بين المستخدمين.في الوقت الحاضر اصبحت هذه الانظمة تحتاج الى متطلبات معينة مثل تامين الحماية للمحادثة من اجل المحافظة على خصوصية الافراد.بالاضافة الى ذلك فان ادائية هذه الانظمة يجب ان تحافظ على مستوى مقبول من وجهة نظر المستخدم. في هذا البحث تم التطرق الى تصميم وبناء منظومة محادثة يدعم الوسائط الاساسية الثلاث للبيانات (نص ,صوت,فيديو).هذا النظام يتكون من جزئين رئيسيين : محادثة خاصة (بين شخصين فقط( ومحادثة عامة (بين شخصين فما فوق). بناء المنظومة تم تنفيذه باستخدام بروتوكولات الشبكات المعروفة بال(TCP, UDP , RTP) لنقل المحادثة اما تامين فقد تم تحقيقه خليط من خوارزميات الحماية المعروفة بال (RSA, AES, SHA512 ,ECCDiffieHellman).هذه الخوارزميات تم استخدامها من اجل تحقيق ثلاثة اهداف وهي الخصوصية والموثوقية وسلامة البيانات لمختلف العمليات التي تحدث في النظام مثل تسجيل الدخول وتبادل المفاتيح وغيرها من العمليات.ايضا هناك العديد من الاختبارات التي تم اجراؤها على النظام وباستخدام العديد من الادوات وذلك للتحقق من فعالية نظام الحماية المقترح .ايضا تم اجراء اختبارات اخرى لقياس الوقت المستغرق من قبل العمليات المختلفة بعد تطبيق نظام الحماية لمعرفة تاثيرها على كفاءة النظام ككل قبل وبعد تطبيق نظام الحماية. عملية التصميم والتنفيذ للنظام المقترح انجزت من خلال مفاهيم تصميم كائني المنحى، والحزمة البرمجية باستخدام Visual Studio 2010، لتحقيق الهدف الاساس للمنظومة المقترحة

نظام تعريف البصمة باستخدام الخوارزمية الجينية == Fingerprint Identification SystemUsing Genetic Algorithm

اسم المؤلف: ذكرى محمد عبد
اسم المشرف: ضياء عبد الحسين جمعة الزبيدي
الموضوع العام: علوم الحاسبات
السنة: 2014
الموضوع الدقيق: علوم الحاسبات
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: Identification system has been widely covered by many researchers using different methods to reach to the desired goal of the best and accurate security method. Existing security methods rely on knowledge based on approaches like password or token based on approaches like access cards. Such methods are not very secure, biometrics such as fingerprint, face and voice offer are means of personal identification and provide increased security because they rely on characteristics are existed in us. In this thesis, method of fingerprint identification system is introduced. The proposed system has used 196 fingerprint image back to the 28 individual, 140 image from them has been used for training and 56 image has been used for testing. Discrete Cosine Transform has been used to extract distinctive features from fingerprint image and genetic algorithm (GA) has been used as features selection technique. Genetic algorithm has helped to produce GA filter in order to select subset of features out of DCT. When testing the proposed system by using two type of statistical pattern recognition, (Probabilistic Neural Network and K - Nearest Neighbor) have found the identification rate reaching to 91% with superiority K - Nearest Neighbor algorithm in reaching this rate with the use of less number of features (68 feature). This rate has emboldened on attempting using more than one filter of genetic algorithm, the result reached to 98% as identification rate in two classifiers with more reduction in number features. The proposed system has been tested before using genetic algorithm and identification rate has reached to 89%. A code for the proposed identification system has been written with the use of matlabversion(7.6).As the specifications of the computer, which is used : Operating System : Windows 7, Processor : 2GHz, Memory : 3072MB

ضغط الصورة كسوريا بالاعتماد على التقنية العشوائية == Fractal Image Compression Based on Entropy Technique

اسم المؤلف: دعاء يونس عباس الطائي
اسم المشرف: جميلة حربي سعود العامري
الموضوع العام: علوم الحاسبات
السنة: 2014
الموضوع الدقيق: علوم الحاسبات
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: ضغط البيانات اصبح مسالة مهمة لخزن المعلومات والارسال ويستخدم بصورة خاصة في قاعدة بيانات مكونة من عدد كبير من الصور الرقمية المفصلة حيث ان الصورة هي عبارة عن تمثيل رقمي. ضغط الصور ببساطة يدل على تقليل هذه البيانات الرقمية بواسطة استخدام خوارزميات مختلفة لذلك مؤخرا الصور تضغط باستخدام خوارزميات ضغط الصور الكسورية وبالاعتماد على الكسوريات (fractals( تعتبر خوارزميات ضغط الصور الكسورية هي خوارزميات من نوع فاقدة لبيانات (lossy) الصور الرقمية. تضغط الصورة كسوريا بسبب اعتمادها على حقيقة ان اجزاء من الصورة غالبا ما تشابه اجزاء اخرى من نفس الصورة لذلك فان هذه الخوارزميات تكون ملائمة اكثر للصور النسيجية والصور الطبيعية. بسبب امتلاك الخوارزميات الكسورية لبعض الخصائص المرغوب بها مثل قدرة التحليل المستقلة وسرعة اعادة الترميز. فان خوارزميات ضغط الصور الكسورية نالت اهتمام كبير من قبل الوحدات البحثية. بالرغم من كل هذه النجاحات المتقدمة الا ان طول وقت الترميز في مرحلة الضغط يبقى العائق الاساسي لهذه الخوارزمية بسبب ان معظم الوقت في مرحلة الضغط يصرف حول ايجاد افضل مطابقة بين المديات (srange) والمجالات (sdomain) اي ايجاد المناطق المتشابهة في الصورة. في هذه الرسالة سوف نقدم تقنية جديدة لتقليل تعقيدات مرحلة الضغط والمحافظة على كفاءة الصورة المسترجعة باستخدام التقنية العشوائية. في هذه التقنية المقترحة, سوف نقسم الصورة المراد ضغطها باستخدام تقنية الشجرة الرباعية quad tree)) الى مديات ومجالات مختلفة الحجم فيما بعد يتم حساب قيمة العشوائية لكل مدى ومجال اذا كان فرق العشوائية بينهما اقل من مقدار عتبة العشوائية (ɛ) الذي يكون ضمن قيم تتدرج من 0.1الى 0.9 فالمجال ينظم لمستودع المجالاتdomain pool) ) لهذا البحث في مستودع المجالات لكل مدى سوف يقل حيث يتم تكوين مستودع المجالات الجديد المتقلص الحجم بالاعتماد على القيمة العشوائية لكل مجال لذلك كل مدى سوف يقارن فقط مع المجالات التي تحقق الشرط ) مستودع المجالات الجديد المتقلص الحجم ) بدلا من المقارنة مع كل المجالات كما في خوارزمية البحث الكلي لهذا الحسابات في مرحلة الضغط المقترحة سوف تكون قليلة والوقت سوف يسرع. في النهاية, استخدام طريقة تقطيع الشجرة الرباعية في التقنية العشوائية المقترحة ساعدنا في تسريع وقت الضغط حيث كما نعرف ان طريقة تقطيع الشجرة الرباعية تسرع مرحلة الضغط حيث ان النتائج الاختبارية في جداول المقارنة المعروضة في الفصل الرابع والتي تتضمن 10 صور رمادية وملونة حجمها 256 ×256 تشير ان الخوارزمية المقترحة تسترجع الصور بوقت ضغط اسرع مثال على ذلك وقت الضغط لصورة لينا تناقص من 2650 ثانية باستخدام خوارزمية الضغط الكلي ليكون431.81 ثانية باستخدام الخوارزمية المقترحة وباستخدام نفس متغيرات مرحلة الضغط وفي حالة قيمة مقدار التداخل (step size) هي 1 كذلك نسبة الضغط والكفاءة لصورة لينا باستخدام الخوارزمية المقترحة هي 10.565 , 30.181 dB على التوالي هذا يعني ان الخوارزمية المقترحة ايضا تحقق كفاءة جيدة للصورة المسترجعة مع نسبة ضغط مقبولة | Data compression has become an important issue for information storage and transmission. This is especially true for databases consisting of a large number of detailed digital images whereas digital images are the numerical representations. Image compression simply refers to reduce this numerical data by using various algorithms so recently images can be compressed using fractal compression algorithm. Based on fractals, fractal image compression is a lossy compression algorithm for digital images. Because fractal image compression relying on the fact that parts of an image often resemble other parts of the same image in other words its is based on the self - similarities property in images so fractal image compression algorithm is best suited for textures and natural images. Due to some desirable properties like resolution independence and fast decoding, fractal image compression has received much attention from the research community. Despite the advances made, the long computing times in the encoding stage remain the main drawback of this algorithm since most of the time during encoding stage is spent for finding the best matching pair of range - domain block (finding the regions with high self - similarity). In this thesis, new technique will be presented to reduce the complexity of the encoding stage and keeping quality of the reconstructed image using the entropy technique. In the proposed entropy technique, the image will be partitioned using quad tree partitioning into range and domain blocks of different sizes after that the entropy values of range and domain blocks will be calculated for determining size of the domain pool since if the difference between the entropy values of range and domain blocks lesser than entropy threshold (ɛ) that ranged from 0.1 to 0.9 values then this domain block will belong to the domain pool because that the domain pool search for each range block will be reduced since the new reduced domain pool is formed based on entropy value of each domain block so that range block is compared only with domain blocks that satisfy the condition (i.e., reduced domain pool) instead of all the domain blocks as in full search algorithm then calculations of the proposed encoding stage will be little and the time will be speeded. Ultimately, using quad tree partitioning in entropy technique assisted in speeding the encoding time since where the experimental results in comparing tables that shown in chapter four which include 10 grey scale and color images of size 256 × 256 indicate that the proposed entropy technique combined with quad tree partitioning reconstructed the images with faster encoding time for example the encoding time of Lenna image decreased from 2650 sec in full search algorithm to be 431.80 sec by using the proposed entropy algorithm under the same encoding parameter values for step size is 1 as well as the compression ratio and quality of Lenna image using entropy technique are 10.565 and 30.038 dB respectively while in full search algorithm were 13.058 and 31.181 dB respectively this means that the proposed entropy algorithm also it achieves good quality of the reconstructed images with acceptable compression ratio

نظام تشخيص السكري باستخدام خوارزمية ID3 وخوارزمية البيز == Diabetes Diagnosis System Using ID3 and Bayesian Algorithms

اسم المؤلف: احلام راشد خرباط
اسم المشرف: زكي سعيد توفيق | سكينة حسن هاشم
الموضوع العام: علوم الحاسبات
السنة: 2014
الموضوع الدقيق: علوم الحاسبات
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: In today’s world, people get affected by many diseases which cannot be completely cured. Diabetes is one of these diseases and is now a big growing health problem. It leads to heart attack, kidney failure and renal disease risks. The techniques of data mining have been widely applied to extract knowledge from medical databases. This work presents a proposed Medical Diagnosis System of Diabetes aiming to identify the correct diagnosis of Patient’s diabetes as quickly as possible and at a lower cost as possible. The Proposal has three subsequent stages; the first stage is to construct the medical dataset (MD) with eight features which are taken for 1000 patients and cover three classes (Diabetic, Non - Diabetic, and Predicted - Diabetic). The second stage is preprocessing the MD by removing redundancy, generalize and normalize some of features values, and to predict the missing values using K - Nearest Neighbor algorithm (KNN) instead of the traditional filling method in which values are estimated based on experiences. The third stage is data mining - based machine learning, which depends on two algorithms Interactive Dichotomizer 3 (ID3) classifier and Traditional Naïve Bayesian (TNB). TNB required an additional checking step to be suitable for the domain; this version has been called Modified Naïve Bayesian (MNB)). The outcome of implementing the proposed system showed that the accuracy of MNB classifier is generally higher than that of both TNB and ID3 classifiers for all feature sets. It has been found that accuracy of the ID3 model is approximately (98.5%), while the accuracy of the TNB model is about (63%) and the accuracy of the MNB model is (100%). The implementation of the proposal has been done using MS. Visual Studio C#.

نظام تمييز الكيانات ثنائية البعد باستخدام تقنية مطابقة المخططات == 2D Object Recognition System Using Graph Matching Technique

اسم المؤلف: اســــراء محمد حســون
اسم المشرف: عامر صديق الملاح
الموضوع العام: علوم الحاسبات
السنة: 2014
الموضوع الدقيق: علوم الحاسبات
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: يستطيع الانسان تمييز الكيانات بجهد قليل بالرغم من حقيقة ان صورة الكيان مختلفة في الحجم والوضعية التي يتخذها الكيان .مطابقة كيانين تنفذ بقياس مدى توافق مميزات وتنظيم الاجزاء الاولية المكونة للشكل . يعتبر المخطط هيكل بياني عام وقوي لتمثيل البيانات .هنالك عدد من المناهج في مطابقة المخططات مثل التمييز بواسطة المكونات , المخطط الهيكلي بالاعتماد على نقاط التقاطع, استخدام خصائص نقاط الـ(Medial Axis) كسمة للشكل. في هذه الاطروحة, تم تقديم نظام تمييز الكيانات ثنائية البعد باستخدام تقنية مطابقة المخططات . الشكل يجزا الى اجزاء اولية منظمة هرميا, ان بناء (Shock Graph) يعتمد على مصفوفة المتجاورات التي تعكس الارتباطات بين مقاطع الهيكل العظمي . النظام المقترح يتضمن اربع مراحل : مرحلة التجهيز , مرحلة بناء المخطط, مرحلة استخلاص الميزات ,واخيرا مرحلة التمييز. مبدا العقوبة سيستخدم في المرحلة الرابعة للاهتمام بالمخططات التي تمتلك حجم مختلف. هذا العمل انجز على قاعدة بيانات تحوي على (100) صورة مقسمة الى (10) اصناف (10) صور لكل صنف. الصور المختبرة تتكون من (80) صورة (8) صور لكل صنف. النظام يستخلص الميزات ويقارنها مع تلك المخزونة في قاعدة البيانات لايجاد اقرب كلاس باستخدام مقياس الفرق الاقليدي. اظهرت نتائج التجارب ان نسبة التمييز كانت 93,7 . | Humans can recognize objects with little effort, despite the fact that the image of the objects may vary in sizes and pose. Matching two objects is perform by measuring how well the proprieties and the organization of the primitives forming the shapes agree .Graph is a general and powerful data structure for the representation of objects, there have been several approaches in graph matching area, such that : recognition by components (geons) ,skeletal graph based on junction points , using medial axis characteristic points as an attribute to model the shape ,..etc. In this thesis, 2D object recognition system is introduced using graph matching technique .A shape is partitioned into hierarchically organized primitive parts, building shock graph is based on adjacency matrix that reflects connections among skeleton segments. The proposed system includes four stages : preprocessing, graph construction ,feature extraction, and recognition stage. To ensure accuracy , principle of penalty is used in the fourth stage to deal with graphs have deferent size . This work is performed on the database including 100 images for 10 classes(10 images for each class). The testing images consists of 80 images(8 images for each class), the system extracts features , and compares the features with those stored in the database to find the nearest class using Euclidian distance measure. The experimental results showed that the recognition rate was 93.7 % .

تقييم تاثير التغير المناخي العالمي على درجة حرارة الهواء في العراق باستخدام نماذج المناخ == Evaluating of the Impact of Global Climate Change on Air Temperature in Iraq using Climate Models

اسم المؤلف: میلاء محمد كاظم الجبوري
اسم المشرف: قیس جمیل الجمیلي | بدور یاسین حمود
الموضوع العام: علوم الجو
السنة: 2014
الموضوع الدقيق: علوم الجو
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: Global warming and climate change refer to an increase in average global temperatures. Natural events and human activities are believed to be contributing to an increase in average global temperatures. This is caused primarily by increases in “greenhouse” gases such as Carbon Dioxide (CO2). The aim of this research is to use simple climate mathematical models to investigate effects of various parameters, functions, and components of the climate system on the temperature rise. Also it aims toward the use of the output of complex climate models to explore the future rise of temperature over Iraq for the 21st century. The results indicated that the increase in diffusivity causes an increase in the heat flux towards the poles causing the temperature to increase in the polar regions and sub polar regions and to decrease in the tropics and subtropics regions. Solar radiation plays a major role in the climate system. It was found that a change of +/˗0.1 of its current value could led the Earth surface to be ice free/totally covered with ice. The results showed that changes in upward longwave radiation can mostly affect polar and sub polar regions. The effect of Hadley cell is to increase the heat flux towards the poles and therefore increasing temperature in these regions and reducing it in the tropics. The results for the simulation of land/ocean combinations for different initial temperatures showed that the combination of most amount of water cover was closest to the initial temperature for all initial temperatures and the combination of most land cover was the farthest distribution from the initial temperature. Analysis of the output of the Intergovernmental Panel on Climate Change (IPCC) models for Iraq showed that global warming will affect Iraq in this century. For the mid - century the temperature will be increased by 0.5 to 2.5 oC and summer months will be the most affected time of the year. The results suggested that by the end of the century temperature will be increased by 3.5 to 4.5 oC and also summer months will be the most affected time of the year. Comparison of the 16 models and three scenarios (B1, A1B and A2) of the IPCC Baghdad showed that for mid - century the scenario B1 gave the lowest increase of temperature for all months, while the scenarios A1B and A2 gives the highest increase of temperature for most of months for all models. For the end of century, it was found that in this period the scenario A2 gives the highest increase of temperature for most of the models, while scenario B1 give the lowest increase temperature for most of models.

Modeling the effect of virtual temperature on take - off and landing operations of aircraft

اسم المؤلف: مهند توفيق امين
اسم المشرف: نعمة محسن لفتة الفتلاوي
الموضوع العام: علوم الجو
السنة: 2014
الموضوع الدقيق: علوم الجو
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: This Thesis focuses on the role of virtual temperature during Take - off and Landing performance, any increase in temperature or altitude means a decrease in the aircraft's optimum performance, so both of high temperature and high elevation airports, an airplane requires more runway to take off. Its rate of climb will be less (during take - off), its approach will be faster (during landing). The increase in temperature leads to a marked increase in radius of turn (during take - off and landing) but a tiny decrease in obstacle angle (during take - off) and a small increase in flare height (during landing).The effect of virtual temperature of five Iraqi airports (Mosul, Erbil, Sulaimaniyha, Baghdad and Basra), and the data base for an extended period was from January 2008 until the month of February 2014. Information was selected for weather report for certain days of the summer season (May, June, July, August and September), where the maximum temperature recorded was 50 ° C for airports Basra and Baghdad, the maximum temperature recorded during the period studied at the Mosul airport,48 ° C at the Erbil airport 44 ° C and Sulaymaniyah airport 43 ° C . Certain days of the winter season (December, January, February) were selected where the minimum temperature recorded the lowest, lowest temperature recorded in Basra airport 6° C, Baghdad airport 2 ° C, Mosul - 1 ° C, Erbil - 2 ° C and Sulaymaniyah - 8° C. The effect of virtual temperature was calculated for five Iraqi airports from comparing the most requirements affect (radius of turn, Distance and stalling velocity) in winter/summer with typical requirement (measured at ISA), the comparing use of actual values and their average during a case study in every airport, icy aerodrome which is considered as an extreme type and calculate its effect in Baghdad and Basra airport. Simulation software program shows us Perfect take - off and landing which are usually preceded by a deliberate planning for approaching the most appropriate velocities. The simulation which was edited is named R.O.T.A.L. (Requirements of Take - off and Landing).This simulation used a set of covering equations programed in visual basic and other programs of medi

تقدير تاخير الانتشار المحتث في اشارات نظام تحديد المواقع العالمي بواسطة المكونات الجوية == Estimation propagation delay induced in GPS signals by atmospheric constituents

اسم المؤلف: فايز هلال صالح الزيادي
اسم المشرف: ضياء عزيز بلال
الموضوع العام: علوم الجو
السنة: 2014
الموضوع الدقيق: علوم الجو
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: عندما تنتقل الموجات الراديوية خلال الغلاف الجوي الارضي المتعادل , فان الاشارات الراديوية تتاثر بتغير معامل انكساره بصورة واضحة , والذي يتسبب بصورة ابتدائية في تاخير وصولها , وفي العادة هذا يشير الى التاخير الناتج من التروبوسفير . ان نظام تحديد المواقع العالمي (GPS) هو عبارة عن الملاحة الراديوية الفضائية .ان المستلم في نظام (GPS) يقوم بتزويد معلومات الموقع والوقت الدقيقين ولعدد غير محدد من المستعملين وفي كل الظروف الجوية , نهارا وليلا في اي مكان في العالم . ان (GPS) يستخدم ثلاثة ترددات والتي هي (L1 = 1.57542 GHz) , (L2 = 1.22760 GHz) و(L3 = 1.38105 GHz) . ان الهواء الجاف , بخار الماء , الجسيمات الجوية المائية والجسيمات الاخرى (التراب , الغبار والعوالق الجوية) في الغلاف الجوي تسبب تاخير في انتقال الموجات الراديوية .هذه التاخيرات يجب ان تكون موصوفة بدقة من اجل الحصول على الدقة الاعلى في المسح الارضي والتحسس النائي باستعمال اشارات نظام تحديد المواقع العالمي (GPS) . يركز الجزء العملي بصورة رئيسية على كيفية توضيح ونمذجة تاثيرات المكونات الجوية مثل الجليد , بخار الماء , الاوكسجين , الغيوم , المطر والثلج على ترددات (GPS) (L1 , L2 وL3) . النتائج توضح ان الجزء الحقيقي والجزء الخيالي لمعامل الانكسار المعقد للجليد يتزايد مع الزيادة في درجات الحرارة اما للماء فانها تنخفض مع الزيادة في درجة الحرارة , لكن بصورة عامة فان معامل الانكسار المعقد للماء يكون اعلى منه للجليد . كذلك فان قيم التوهين الناتجة عن قطيرات الغيمة النقية بواسطة رايلي هي اكبر من قيمها الناتجة عن قطرات المطر النقية بواسطة مي للترددات الثلاثة , وهذه القيم تتناقص مع الزيادة في درجة الحرارة وتزداد مع الزيادة في التردد . ان لكل من طيف بخار الماء والاوكسجين منطقتين تمتلكان اعلى قيم للتوهين (ان لكل من طيف بخار الماء والاوكسجين منطقتين تمتلكان اعلى قيم للتوهين ( GHz183 ,GHz 325 لبخار الماء وGHz 60 , GHz 118 للاوكسجين ) . ان تغير الطور التفاوتي (∅∆) في حالة المطر يحصل بواسطة قطرة المطر المفلطحة والتي لها محورين مختلفين وبسبب الاختلاف في تركيز قطرات المطر , ايضا فان (∅∆) لا تعتمد على درجات الحرارة لكنها تزداد مع زيادة التردد حيث تكون قيم (∅∆) deg/km 6 لـ (L1) , deg/km 5 لـ (L2) وdeg/km 5.4 لـ (L3) . بالاضافة الى اعتماد التوهين التفاوتي (∆A) في حالة المطر على شكل قطرة المطر وتركيز القطرات فانه يعتمد على درجة الحرارة والتردد . ان (∅∆) في حالة الثلج تحصل بواسطة الشكل غير المنتظم لجسيم الثلج وتعتمد على درجات الحرارة والتردد . ان (A∆) في حالة الثلج تمتلك قيم واطئة جدا في درجات الحرارة المختلفة والترددات المختلفة | When radio waves propagate through the earth’s neutral atmosphere, the radio signals are affected significantly by the variability of its refractive index, which causes primarily in the delay of the arrival, usually referred to as the tropospheric delay . The Global Positioning System (GPS) is a space - based radio navigation . The GPS system receiver provides exact location and time information for an unlimited number of users in all weather conditions, day and night, anywhere in the world. The GPS uses three frequencies that are (L1 = 1.57542 GHz , L2 = 1.22760 GHz and L3 = 1.38105 GHz) . Dry air, water vapor, hydrometeors and other particulates (sand, dust and aerosols) in the atmosphere introduce radio waves propagation delays. These delays must be properly characterized to achieve the highest accuracy in surveying and atmospheric sensing using Global Positioning System (GPS) signals . This work mainly focuses on the illustration of a model showing the effects of the atmospheric constituents such as ice and snow, water vapor , oxygen , clouds , rain on the GPS frequencies (L1 , L2 and L3) .The results show that the real and imaginary parts of complex refractive index for ice increase with the increase of the temperature and for water decrease with the increase of the temperature , but generally , the complex refractive index of water is higher than that of ice . Also , the attenuation values that are induced by pure cloud droplets by Rayleigh are higher than the attenuation values that are induced by pure water drops by Mie for the three frequencies , and these values decrease with the increase of the temperature and increase with the increase of the frequency . Each of water vapor and oxygen molecules have a small effect on radio waves in troposphere . The differential phase shift (∆∅) in case of rain is caused by the oblate rain drop that is has two different axes ,and because of the difference of the concentration of rain drops, also (∆∅) doesn't depend on the temperature but increase with the increase of the frequency where the values of (∆∅) are 6 deg/km for L1 , 5 deg/km for L2 and 5.4 deg/km for L3 . In case of rain , the differential attenuation (∆A) in addition to depend on the shape and the concentration of drops , it depends on the temperature and the frequency . In case of snow , the (∆∅) caused by the irregular shape of snow particle and depends on the temperature and the frequency . The (∆A) in case of snow has very low values in different temperatures and frequencies

تنبؤ احصائي لسرع الرياح لمحطات محددة في العراق == Statistical Forecasting of Wind Speed for Selected Stations in Iraq

اسم المؤلف: سرى ثامر ناصر
اسم المشرف: بدور ياسين حمود العامري | محمد احمد صالح ابو الطيب
الموضوع العام: علوم الجو
السنة: 2014
الموضوع الدقيق: علوم الجو
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: Wind speed is one of the most meteorological variables which has been changing rapidly with time. Due to the properties of wind speed such as non - stationarity, high fluctuations and irregularity. accurate forecasting becomes a challenge because, The wind speed is easily influenced by many factors, such as latitude, altitude, terrain, pressure, temperature. Therefore, The forecasting of the wind speed is important for many environmental, economic and meteorological applications. Due to the difficulties of the physical models and their non - availability, The Box - Jenkins ARIMA model has been used .Because, it is suitable tool to predict the wind speed and can also be used as an effective tool to get the missing data which existing within the time series of monthly mean wind speed. When Box - Jenkins ARIMA model has used, The ARIMA (15,1,10) model has determined as a suitable model for the monthly mean wind speed for studied stations in Iraqi after passing through the four stages of the model that include Identification of The Time Series, Estimation of The Model Parameters, Diagnostic Check of The Residuals and Model Adequacy and finally, The Forecasting. Many of the evaluation criteria have been used to check the accuracy of the best proposed prediction models by lowest values of each MAE and RMSE and MAPE and the highest values of the correlation coefficient (R2) and correlation coefficient (r), which confirmed the preference of ARIMA(15,1,10) for the monthly mean of wind speed but, This model could not applied on the daily mean of wind speed due to difficult in chose one best - fit model for all time series in all regions of Iraq. Because, The large variance of the wind speed during day and night and has not appeared clear correlation in all stations as shown in monthly data. The best solution is to take the difference of the non - stationarity time series from one lag to the next and then analyze this series after reaching to stationarity. The time series of daily wind speed need to take the difference once for the Baghdad station (d = 1) and twice for the Kirkuk station (d = 2) and three times for the Nasiriya station (d = 3) for reaching to stationarity. When ARIMA(15,1,10) model has been used, All the residuals were found within the confidence intervals and The error rate of using MAPE measure has been found near ( 4% ) for all studied stations in Iraq .

تحليل الانماط الزمانية والمكانية للاوزون فوق العراق == nalysis of temporal and spatial patterns of ozone over Iraq

اسم المؤلف: زهراء موسى حسن
اسم المشرف: علي محمد عبد الرحمن الصالحي
الموضوع العام: علوم الجو
السنة: 2014
الموضوع الدقيق: علوم الجو
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: onthly and annual values of the total column ozone amount have been analyzed for five locations of Iraq for the period from 1979 to 2012 employing Total ozone Mapping Spectrometer (TOMS) data point and (1o × 1.25o ) grid data, It is found that ozone variation is function of latitude, where the higher values of total ozone column occurs at the northern Iraq which represented by Mosul location, it decreases gradually from northern location (Mosul) passing by middle region locations (Biji, Baghdad and Rutba) to southern location (Basra). The values of Total ozone column start to increase gradually from November to reach its maximum at March then it decreases gradually to reach its minimum values at October. The analysis of the spatial distribution of the monthly average of total ozone column for each month of the year has been made. It is found that the largest of total ozone column amounts occurs systematically over the northern regions during winter whereas in spring and early summer months the maximum values of total ozone column directed to the northwestern regions of the Iraq. Latitudinal gradients in total ozone column are very strong especially during winter, spring and early summer months. The spatiotemporal trend analysis has been made by converting the gridded data from time domain to spatial domain, it is found that the results show that the total ozone column trends was negative during most months of the year, whereas the spatial trend analysis of the second period of study (2005 - 2012) presented positive total ozone column during all months of the year except February and September which presented a negative trends and the overall presented positive trends varied from 0.1 to 2.3 DU / year. Finally the results of the two period trend analysis indicated that the ozonelayer may be responding as expected to the reducing on ozone - depleting substances imposed by the Montreal Protocol.

تاثير درجة حرارة سطح البحر المتوسط على درجة حرارة الهواء السطحية والامطار لبعض المواقع في الشرق الاوسط == The effect of Mediterranean Sea surface temperature on air surface temperature and rainfall for some locations in the Middle East

اسم المؤلف: حنين حاكم عبد الرضا عباس
اسم المشرف: منعم حكيم خلف الجبوري
الموضوع العام: علوم الجو
السنة: 2014
الموضوع الدقيق: علوم الجو
الدرجة: دكتوراه
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: درجة حرارة سطح البحر تلعب دور مهم في التغير المناخي لانها تؤثر على درجة حرارة الهواء مباشرة فوق السطح ومعدل التبخر للماء والذي يؤثر بدوره على درجة حرارة الهواء وتكوين الغيوم والامطار. لذلك دراسة درجة حرارة سطح البحر مهمه في حل المشاكل للظواهر الجوية والبحرية ونظام المناخ للارض. يهدف هذا البحث الى دراسة تاثير تغيرات درجة حرارة سطح البحرالابيض المتوسط(SST) على درجة حرارة الهواء السطحية(T2M) والامطار(TP) لمنطقة الشرق الاوسط خلال الفترة .(1980 - 2009) البيانات المستخدمة في هذه الدراسة تم الحصول عليها من المركز الاوربي وتم عمل ثلاث شبكات للمتغيرات لايجاد العلاقة بين SST وT2MوTP ب استخدام طريقتين للتحليل الاحصائي. ففي الجزء الاول من الدراسة تم استخدام طرق التحليل الاحصائي مثل السلاسل الزمنية ومعامل الارتباط, وتم اختيار ثلاث مواقع (نقاط) على الشبكة في البحر المتوسط واربع مناطق في الشرق الاوسط (بغداد, عمان, دمشق, بيروت).النتائج اظهرت ان التغيرات في درجة حرارة سطح البحر لها اكبر قيمة للميل في شهر تموز (0.06) للنقاط الثلاثة واقل قيمة كانت في الفصول الانتقالية, في شهر نيسان كانت (0.01) للنقطتين الاولى والثالثة, في شهرتشرين الاول كانت قيمة الميل (0.04) في النقطة الثالثة. اما اعلى قيمة للميل لدرجة حرارة الهواء السطحية في الشرق الاوسط فكانت في شهر تموز (0.06) في مدينتي بغداد ودمشق وكانت اقل قيمة في شهر نيسان (0.006 - ) في مدينة عمان. بالنسبة لقيمة الميل للامطار فكانت اعلى قيمة في عمان وبيروت (0.3) خلال شهري كانون الاول وشباط على التوالي, واقل قيمة للميل كانت في بغداد (0.27 - ) خلال شهر كانون الاول. بينت النتائج ان درجة حرارة سطح البحر لها اكبر تاثير على درجة حرارة الهواء السطحية في شهر تموز, بسبب ان معامل الارتباط كانت له اعلى قيمة (0.58), (0.48), (0.50), (0.56) للمدن بغداد وعمان ودمشق وبيروت على التوالي خصوصا مع النقطة الاولى. اقل قيمه خصوصا للنقطتين االثانيه والثالثه فكانت في شهر نيسان, (0.007 - ), (0.08 - ), (0.08 - ), (0.08 - ) للمدن بغداد وعمان ودمشق وبيروت على التوالي.ولوحظ انه لاتوجد علاقة بين درجة حرارة سطح البحر والامطار للمناطق الاربع لان معامل الارتباط له قيم قليله في كل المواسم المطرية.في الجزء الثاي من الدراسة فتم استخدام طريقة التحليل بواسطة الدالة التجربيبة المتعامدة (EOF) للتغاير المكاني واخذت اول نمطين للـEOF الاول والثاني (EOF2, EOF1) وطريقة التحليل بواسطة (PC) للتغاير الزمني للنمط الاول (PC1). استخدمت شبكتين للنقاط للبيانات, الاولى تمثل شبكة SST لمنطقة البحر المتوسط والشبكة الثانية تمثل شبكة ((T2M,TP لمنطقة الشرق الاوسط وبقدره تميز 0.50 x 0.50 وقسمت فترة الدراسة الى فترات تمثل كل عشر سنوات.النتائج بينت ان نسبة التغاير المكاني لدرجة حرارة سطح البحر للـEOF1 ودرجة الحرارة السطحية كانت 97% و95% من التغاير الكلي على التوالي , وهذا يشير الى وجود علاقة محتملة بينهم, بينما التغاير المكاني للامطار سجلت اقل قيمة خلال فترة الدراسة.اما التحليل بواسطه التغاير الزمني بواسطه PC للـ SST فقط لوحظ وجود دوره قوية لها عشر قمم كل عشر سنوات من فترة الدراسة. | Sea surface temperature plays an important role in the climate change, because it affects the temperature of the air immediately above the surface, evaporation rate of water, cloud formation and precipitation. Therefore, the study of sea surface temperature is fairly essential for solving many meteorological and oceanographic problems and climate system of the earth. The aim of this thesis is to study the effect of sea surface temperature (SST) variation of Mediterranean Sea on air surface temperature (T2M) and rainfall (TP) in Middle East during the period (1980 - 2009). The data used in this study obtained from the Europe center (ECMWF) and made three grids of the variables in order to determine the relationship between SST and (T2M, TP) by using two statistical analysis methods. In the first part of study, statistical analysis technique used such as time series and correlation coefficient, and select three location (points I,II,III) on the grid of Mediterranean sea and four locations on Middle East (Baghdad, Amman, Damascus, Beirut). The results show that, The variation of SST has the highest value of trend in July (0.06) for the points I, II, III and the lowest value was in the transition season, in April was (0.01) for point I, III, in October was (0.04) for point III. While the highest value of trend for T2M in Middle East was in July (0.06) in Baghdad and Amman city and the lowest value in April ( - 0.006) in Amman city. For the value of trend of rainfall, the highest value was in Amman and Beirut (0.3) in December and February months respectively, and the lowest value of trend was in Baghdad ( - 0.27) in December month. The results show that the SST has the largest impact on T2M in July, because the correlation coefficients has the highest value (0.58), (0.48), (0.50), and (0.56) for Baghdad, Amman, Damascus and Beirut respectively especially for point I. The lowest value of especially for point II, III, in April was ( - 0.07), ( - 0.008), ( - 0.008) and ( - 0.008) for Baghdad, Amman, Damascus and Beirut respectively. And notes there is no relation between SST and TP for the four locations, because the correlation coefficient has small value in all rainfall months. The second part of the study use the Empirical orthogonal function (EOF) for the spatial variance and take the first two EOF (EOF1, EOF2) mode, and principle component analysis (PCA) tool for the temporal variation of (PC1) mode. Two grids of points have been used for the data; the first one represents the SST grid of Mediterranean Sea area and the second one represents the (T2M, TP) grid of Middle East of 0.50 x 0.50 and the period of study divided into periods every 10 years. The results show that the percentage of spatial variation of EOF1 for SST and T2M was 97% and 95% of total variance respectively, that indicate to have possible relationship between them while the spatial variance of TP record the lowest value in the period of study. The analysis made by the temporal variance of PC for SST show it has strong cycle with 10 peaks every 10 years of the period of study.

تاثير اضافة الكالسيوم على البنية المجهرية والخواص الميكانيكية لسبيكة Al - Cu - Mg == Effect of Ca Addition On The Microstructure And Mechanical Properties of Al - Cu - Mg Alloys

اسم المؤلف: نور صباح توفيق
اسم المشرف: منذر محمد راضي
السنة: 2014
الموضوع الدقيق: هندسة المعادن
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: في هذه الرسالة تم دراسة تاثير اضافة عنصر الكالسيوم بنسب مختلفة ) 3.0 المجهرية والخواص الميكانيكية لسبيكة) المنيوم - نحاس - مغنيسيوم ( , حيث تم انتاج هذه السبائك باستخدام والتي تتضمن )المعاملة المحلولية, )? السباكة الرملية وعوملت حراريا باستخدام المعاملة ا | In this thesis ,the effect of pure Ca element addition in different percents of (0.3,0.6,0.9%) on the mechanical properties of Al - Cu - Mg alloy were studied.The Alloys were produced using sand casting and heat treated using T6 which involve [solution treatment , quenching , artificial aging ], aging process were carried out at 220? C for different periods of time ranging between (5min to5hr).Also the work involves a study on the effect of Ca addition on both grain size as well as the resulting phases before and after heat treatment, samples were examined using optical microscope, Scanning Electron microscope ,X - Ray diffractometer and image - J to estimate the average grain size.The results of hardness and tensile tests for 0.6% Ca and 4hr aging shows the best response as compared to the other alloys. The hardness and strength values have been changed from (78.29HV)(110.57Mpa) during (30min)at 220?C for non - Ca content alloy to(125.9HV)(164.2Mpa) for 0.6%Ca alloy. X - Ray diffraction , results shows the basic phase that forms is Al2CuMg (S??, S? phase) which is considered as the main strengthening phase in AL alloys, and it was found that Ca addition leads to form (Al4Ca) and (Al2Ca)which delay the alloy response to precipitation hardening by delaying the formation of (S)phase. SEM images showed a large and small dimple structure and broken or cracked Al - Ca compounds particles.This indicates that the fracture was ductile fracture in the Al matrix and brittle in these compounds ,.Also presence of microvoids (porosity) on the fracture surface is formed at the interfaces between Ca compounds and Al matrix enhanced the crack propagation through their center. The presence of the secondary phases precipitates (Al2CuMg ,Al2Ca and Al4Ca) in the fracture surface also contributed to ameliorate the mechanical properties by increasing the bonding of the matrix and reduced the ductility.Also Ca addition in the range of (0.3 - 0.6%) gives rise to grains refining ,While increasing Ca content up 0.9%wt coarsing the grains, which leads to decrease the hardness and tensile strength, From these results the decrease in tensile strength with increasing Ca content over 0.9% seems to be attributed to the reduction in elongation caused by the occurrence of micro porosity due to Ca addition.

تخطيط مسار نقطي خال من الاصطدام لروبوت ممفصل ذا خمس درجات حرية == Point - To - Point Free Collision Path Planning of 5 DOF Articulated Robot

اسم المؤلف: محمد عبد الرحمن غفور
اسم المشرف: تحسين فاضل عباس
السنة: 2014
الموضوع الدقيق: هندسة الانتاج
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: ان الهدف الرئيسي من هذا البحث هو ايجاد مسار لمفاصل الروبوت وللماسك النهائي في الروبوت خلال حركة الماسك من نقطة البداية الى نقطة الهدف المراد الوصول اليها خلال حيز مؤتمت بدون الاصطدام مع العوائق الموجودة في بيئة الروبوت اعتمادا على الحل العلوي لاذرع الروب | The main objective of this research is to find a path for the robot joints and gripper from the given start point to the desired goal point without collision with the obstacles which exist in the robot environment depending on the robot links upper solution. This research will investigate the problem of path planning for a 5 axis articulated robot, operating in an environment with obstacles whose boundaries are enveloped by a spherical shape. The path planning approach has been developed in the robot joint space and consists of five phases : The first phase is using Bezier, Hermit, B - spline and NURBS curve techniques considering their control points weight not constant. The second phase is to generate a sufficient number of intermediate points in Cartesian space along those curves. The third phase converts the coordinate of the generated intermediate points from its Cartesian space into joint space and move the robot gripper along the generated path. The fourth phase screens the generated four Bezier, Hermite, B - Spline and NURBS paths in order to choose the best one. The fifth phase is developing the chosen path by using proposed algorithm to improve the selected path.Both forward and inverse kinematics solutions for the robot links using Denavite - Hartenberg representation are important step to determine the manipulator's joint angles and Cartesian coordinates, that assists generating the required path which has been derived in this work.Matlab program has been used as an assistant program to analyze, sketch and implement the algorithms of forward kinematics, inverse kinematics and path planning.This work will not be limited to theoretical studies or simulations, experiments have been run with various tests, on "educational robot" Lab - Volt R5150 to assess which path is the better ability in avoiding the obstacles. The method applies to robots in a fixed and known environment. A number of experiments have been carried out to test the ability of the robot arm to reach its goal without collision It’s found that Bezier curve was the chosen path because it was the better obstacle avoidance and shorter path.

دراسة سلوك البلى الترددي لمواد مركبة ذات اساس من سبيكة المنيوم / sic تحت ظروف الانزلاق الجاف والرطب == A Study On The Reciprocating Wear Behavior of Aluminum Alloy / SiC Composites Under Dry And Wet Conditions

اسم المؤلف: عتبة حسين علوان
اسم المشرف: احمد علي اكبر اكبر
السنة: 2014
الموضوع الدقيق: هندسة المعادن
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: تم في هذا البحث دراسة معدل البلى لاحدى سبائك الالمنيوم ((AA2024) (Al - Cu - Mg ومواد مركبة عن طريق تصنيع جهاز بلى ترددي تبعا للمقياس العالمي ( ASTM G133) ذو ترتيبة المسمار على المستوى (Pin on Flat) لمتغيرات مختلفة (الحمل المسلط , النسبة الوزنيه لدقائق كا | In this work the wear rate of one of aluminum alloys (Al - Cu - Mg) (AA 2024) and composite materials, has been studied by manufacturing a reciprocating wear device according to the International Standard (ASTM G 133 Pin on Flat) for different variables (applied load, weight percentage of (SiC) and sliding speed) under dry and wet (lubrication) conditions. Stir casting method has been used to prepare a composite material by using vortex technique to force the particles inside the molten metal (Al - alloy) and to distribute them regularly. The composite materials reinforced with different weight percentages of SiC (3, 6, 9, 12 wt%) are used. The base alloy and composite materials samples were tested to investigate the microstructure, and phases using optical microscope and Vickers hardness, wear rate, and the worn surfaces by using scanning electron microscope (SEM). From the results of microscopic examination it is found that the microstructure of alloy matrix was fine dendrites, in addition to the SiC particles that distributed near homogenously in the alloy matrix. The hardness test results showed that, the increasing of the weight percentage of (SiC) leads to increase the hardness, and the highest value of hardness was found at 12wt% SiC. Also the results showed that the wear rate increases with applied load for all weight percentage of reinforced particles (SiC).With increasing the load, more wear tracks, deep, and closed paths are formed and severe wear happens under dry condition but the lubrication case has less effect than dry case.It was shown that wear rate of both base alloy and composites under various conditions, increases with increasing of applied load and sliding speed but the wear rate decreases with increasing the SiC wt% in composite.Statistical method using software (Minitab 16) was used to study the effect of wear rate for both the base alloy and composite material by using three variables; applied load (X1), silicon carbide proportion (X2), sliding speed (X3), with five levels of each variable. It is concluded that the optimum weight loss under dry case was 0.0014g, The combined effect of variables and the wear rate was obtained and which variable are more influential, as shown in the equation below : D = 0.056703 - 0.002164 X2 - 0.000282 X3+ 0.000017 X1 X3 +0.000010X2 X3 While under lubrication case that the optimum weight loss was 0.0037g and the combined effect of variables and the wear rate was obtained and which variable are more influential, as shown in the equation below : L= 0.009607 + 0.002825 X1 - 0.002375 X2 + 0.001100 X3 + 0.001664 X3 2 + 0.004700 X1 X3 + 0.002700 X2 X3 The applied load (X1) and sliding speed (X3) have the largest effect on wear rate.

السحب العميق المتعدد المراحل للاقداح السداسية == Multistage Deep Drawing of Hexagonal Cups

اسم المؤلف: صبيح سلمان داود
اسم المشرف: وليد خالد جواد
السنة: 2014
الموضوع الدقيق: هندسة الانتاج
الدرجة: دكتوراه
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: The aim of this work is to design and manufacturing a multistage (three stages) deep drawing dies to produce cylindrical and hexagonal cups of (43,33.1,26.8)mm diagonal diameter through two methods. The first method by drawing the hexagonal cups directly by using hexagonal orifice die from a flat sheet (blank) of (80mm) diameter and (0.7) mm sheet thickness for (1006 - AISI) hot rolling low carbon steel material.The second method by redrawing a cylindrical cups of (43,33.1,26.8) mm outer diameter (produced previously by a cylindrical orifice die) in to hexagonal orifice die which transform (convert) these cylindrical cups into hexagonal cups of (43,33.1,26.8)mm diagonal diameter.For all stages of drawing hexagonal cups, wall corner radius of die (0.7, 4)mm, with punch and die profile radius of (4 and 8) mm and drawing speed of (50, 200, 500) mm/min were used to study the effect of these parameter on drawing forces, cup wall thickness, strain distribution over the cup wall and surface defect of the cup wall.A commercially finite element soft ware (ANSYS 11.0)was used to perform the numerical simulation for cylindrical and hexagonal cups in three stages of drawing process. A comparison between theoretical (simulation) and experimental results lie within average of (15 - 20%), and the agreement is good in the first stage.The results shown that excessive metal flow ,maximum thinning of cup wall and maximum strain occurred at corner radius of (0.7) mm and at drawing speed of (500mm/min )for hexagonal cup produced directly from flat sheet.The results shown that the best thickness distribution and strain distribution over the cup wall, better cup wall surface (less surface defects) and lowest drawing force was with percentage (63.8%,45.4%,74.1%) respectively occurred when transform (converting) the cylindrical cup into hexagonal cup with wall corner radius of die (Rc= 4)mm in three stages.

دراسة زاوية تعشق العدة في عمليات التفريز == Studying Tool Engagement Angle In Milling Process

اسم المؤلف: ليث فاضل شاكر
اسم المشرف: ليث عبد الله محمد
السنة: 2014
الموضوع الدقيق: هندسة الانتاج
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: هذه الاطروحة تعنى بدراسة تاثير زاوية تعشيق العدة بالمشغولة على ستراتيجيات ونتائج عمليات التفريز بالعدد ذات النهايات المسطحة. تم تصميم نموذجين (CAD model) باستخدام برنامج (Solid work 2013) الاول على شكل كونتور خارجي والاخر على شكل بوكيت داخلي وبعد ذلك تم | This work focuses on the effect of controlling tool engagement angle (TEA) on the milling process planning and the results of end milling operations. Two CAD models has been designed by using Solid Work 2013 software, then G - code have been generated and simulated by using Surfcam V5 software with (Fanuc post processing). AL7075 - T6 alloy has been used for its high machinability, dry machining (no coolant) has been done on 3 - axes milling machine (C - tek) available in the University of Technology Training and Workshop Center.Feeds, speeds and other machining parameters (axial and redial depth of cut) have been selected according to machining handbooks recommendations. Machining of workpieces has been accomplished by using two techniques (two types of tool - path), first one was conventional tool - path machining (contour parallel tool - path), and the second was by using TRUEMILL technique (true engagement controlled tool - path) by Surfcam V5. Thirty experiment have been designed, four of them have been failed, ten have been accomplished and the others neglected for reasonable causes as it will be discussed. Finally a comparison between the two techniques has been made focusing on machining time, material removal rate, cutting temperature and surface roughness. The results confirm that TEA control leads to reduce machining time, we have a time reduction in about (80%) for contour machining and (57%) for pocket machining. Cutting heat was under control though the feeds and the axial depths of cut went higher, also by controlling tool engagement angle we skipped the cause of failure of some experiment in conventional tool - path machining. Surface roughness was not that affected by controlling tool engagement angle, the minimum surface roughness in hand is (0.43 µm), it is higher than the best result of a previous work for the same material by 50%.

دراسة تجريبية حول مسحوق حبيبات النحاس ذات الحجم النانوي باستخدام الترسيب الكهربائي المصحوب بالامواج الفوق صوتية == Experimental Study of Nanosized Copper Powder Using Sonoelectrodeposition Process

اسم المؤلف: حيدر ياسر ثامر الياسري
اسم المشرف: محمد جاسم كاظم | عدنان شمخي جبر
السنة: 2014
الموضوع الدقيق: هندسة المعادن
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: عملية الترسيب او التحليل الكھربائي تعتبر من الطرق التصنيعية الرئيسية التي تستخدم لانتاج مختلف الاشكال والاحجام (ضمن المدى الميكروي) من حبيبات مسحوق معدن النحاس والتي تستخدم لاحقا بواسطة تكنولوجيا المساحيق لانتاج اجزاء محددة. ايضا استخدمت ھذه الطريقة بمد | Electrolytic or electrodeposition process is considered a main way to produce many shapes and sizes (micro range) of copper powder to be used in powder metallurgy process. It is used broadly to deposit copper coatings with nanosized grains, but it is rarely used to produce nanosized particles of copper. Reaching this goal is highly dependent on the optimum design of the parameters of electrodeposition process.This work aims to study the important variables that most affect the electrodeposition process outputs. These variables are : copper sulphate pentahydrate salt concentration CuSO4.5H2O (1, 5.5, and 10) g/l, cathodic current density (12.5, 25 , and 37.5) mA/cm2, ultrasonic (20 KHz frequency) vibration amplitude (5%, 20%, and 35%) from the maximum amplitude (1 ?m), and amount of sulphuric acid H2SO4 (H2SO4 concentration > 97%) in electrodeposition cell (0.05, 0.10, and 0.15) ml/l. The study of effects of these variables is concerned with size of resultant powder particles, also their effect on the purity, morphology, and shapes of particles is studied, and the crystallinity of particles is also covered.The design of experiment (DOE) approach is applied here through Taguchi design of experiments, to manage and analyze the results and study the specific effects of each. The arrangement of variables’ levels is done using the setup of (Taguchi L9).The analysis of experiment tests of the study of electrodeposition process to get copper nanoparticles showed that all variables have effect on the size of resultant copper particles, but in different ways and degrees. The mean particle size of all samples is about 86 nm. It was found that the increasing of concentration of copper sulphate salt (1, 5.5, and 10) g/l had a negative on the increasing the size of copper particles in the range (71, 69, and 117) nm.While the increasing of cathodic current density (12.5, 25 , and 37.5) mA/cm2 had an effect of decreasing the particle size of copper in the range (114, 75, and 68) nm. The case was the same for increasing of amplitude of ultrasonic vibration, where increasing it (5%, 20%, and 35%) caused decreasing in the particle size in the range (97, 92, and 68) nm. And the effect of acid amount (0.05, 0.10, and 0.15) ml/l was multiple because it decreased the particle size first and increased it later in the range (90, 65, and 102) nm. The amount of effect of each variable on the process was calculated using specific equations of Taguchi design. It was found that the current density has the bigger effect (35%) on the resultant particle size (it minimized the size). The salt copper concentration has the second effect (34%) (it maximized the size), and thirdly the acid concentration effect is 19% (it had multiple effect on the size).Finally the ultrasonic vibration has 12% effect (it minimized the size). The optimum values of process parameters that lead to minimum size of the particles were : CuSO4.5H2O concentration = 5.5 g/l, Current density = 37.5 mA/cm2, Ultrasonic amplitude = 35%, H2SO4 concentration = 0.1 ml/l.The SEM photographs were used to examine the morphology of particles. The results show that the shape and morphology widely vary between many modes : from treelike through irregular, angular, or rounded shapes to a wellfaceted truncated octahedron. The forming of well - faceted truncated octahedron copper particles is related strongly to the presence of ultrasonic vibration which plays the role of inhibitor.Energy dispersive spectroscopy (EDS) elemental analysis of copper nanoparticles indicates the high purity of most of samples except the cases where there are traces of oxygen from very thin layer of oxides and/or carbon from residual alcohol.The x - ray diffraction studies reveal that the resulting particles are a crystalline copper element with a face center cubic (FCC) crystal structure.

تطبيق نظام دعم القرار لانشطة الصيانة في مصفى الدورة == Application of A Decision Support System For Maintenance Activities In Al - Daura Oil Refinery

اسم المؤلف: مصطفى محمد علي منصور
اسم المشرف: لمياء محمد داود | لمى عدنان حميد
السنة: 2014
الموضوع الدقيق: الهندسة الصناعية
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: في ھذا البحث تم دراسة انشطة الصيانة في معمل دھون 3 احد معامل الدھون في مصفى الدورة حيث تم اختيار ھذا المعمل كونھ الاحدث والاكثر انتاجية مقارنة مع المعملين الاخرين وتم اخذ بيانات انشطة الصيانة لمدة عشر اشھر متتاليھ من ايار 2012 ولغاية شباط 2013 علما ان وح | In this research maintenance activities in lube oil factory (3) of Daura refineries is investigated for ten consecutive months from May (2012) to February (2013).This factory is the newest and largest in its capacity compared with lube oil factory (1 and 2). Dewaxing unit produces the greater products compared with other production units in lube oil factory (3). The frequency of breakdowns and type of maintenance were identified, Pareto chart are used to analyze the collected data. Results indicated that %95 of breakdowns of different equipments (pumps, exchangers, compressors, docks, filters, furnaces and towers) are due to mechanical causes, the rest are related to electrical causes.Pareto chart highlights that the most frequent failure for both pumps and exchangers followed by compressors and other equipments of lube oil factory 3.Loss production cost due to maintenance activities was also conducted in this study so as to analyze different aspects of maintenance activities for lube oil factory (3).The total loss in production due to breakdown in the ten months of this study is (99 Billion ID). It is worth’s mentioning that pumps registered the highest losses of production cost due to bad maintenance. Accordingly, decision making for maintenance activities is a multiattribute and decision support system is crucial to signify priorities and definealternatives. ERGO (Latin word meaning "therefore" or Greek word meaning "work", used as a prefix ergo - , for example, in ergonomics and it is generalpurpose decision support system using 35 criterion to choose the best alternatives) is employed so as to evaluate detailed scope and the best of best alternatives. ERGO results indicated that Pumps are the best alternative offered to decision maker to conduct the necessary maintenance ERGO identifies the equipment with the most frequent breakdown indewaxing unit, which causes the greater loss in production cost. Compressors were identified as the highest frequency failure equipment(s). Combining two criteria (frequency of failure and lost production cost) reveals that pumps are the best alternative.

تقليل ضياعات القص في مشكلة قطع الخامات احادية البعد باستخدام نموذج برنامج جاهز == Trim Loss Minimization In One - Dimensional Cutting Stock Problem Using A Ready Software Model

اسم المؤلف: سلام قدوري داود
اسم المشرف: سوسن صبيح الزبيدي
السنة: 2014
الموضوع الدقيق: الهندسة الصناعية
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: تعتبر مشكلة قص الخامات واحدة من المشاكـل العملية المهمـة، لذا ركز البحث على دراسة مشكلة قص الخامات احادية البعد بالتفصيل، حيث تم دراسة تصنيف وخصائص وطرق حل هذا النوع من المشاكل بالاضافـة الى اقتراح اسلـوب حـل مناسب لتقليل ضياعات القص الحاصلـة في بيئـة ا | Cutting stock problem is one of the important operation problems. The one dimensional cutting stock problem is considered as obvious problem which should be centered to be solved, so this thesis focuses on studying classification, characteristics and solution methods for this problem, in addition to suggest suitable approach for minimization of the trim losses in actual environment, as it is required to fulfill all of the small required items with different lengths and quantities by cutting the identical large objects which are available as stock. The variety of lengths and quantities of these small required items makes the problem obvious in complexity to fulfill all items with minimization of Integer Linear Programing (ILP) which is aided by Advanced Interactive Multidimensional Modeling System (AIMMS) software used to solve research problems. This software used because that getting of accurate details and speed results for waste amounts, number of used stocks, total and efficient cutting patterns that are generated to getoptimal solutions.Our study has been applied in an actual environment (housing project with 41 building units in Azezeiyah - Wasset) being carried out by Al - Mansour Company of Iraq Ministry of Construction and Housing, where the reinforcement steel (Rebar) with standard length is considered as a backbone component of building structure.These problems have been studied according to different rebar diameter (25 mm, 16 mm, 12 mm, and 10 mm), where each problem is subdivided and solved according to basic building activity designs (foundation, columns, beams, slabs, stairs, balcony, and front arch building entrance), trim losses which were resulting from certain activity design - diameter problem that have lengths longer than required item lengths in the next activity designs are stored and utilized to get optimal stock ratios. The utilization stock ratio which is resulting of suggested solution approach (ILP) for all these one dimensional cutting stock problems has reached (98.53%), while the utilization of used stock in that actual environment got by Al - Mansour Company is lower than this percentage.

تاثير المعاملة بالليزر على مقاومة التاكل للفولاذ المقاوم للصدا نوع 304 == Effect of Laser Treatment On Corrosion Resistance of 304 Stainless Steel

اسم المؤلف: زمن عبد الرزاق عبد الوهاب
اسم المشرف: محمد جاسم كاظم | سامي ابراهيم جعفر
السنة: 2014
الموضوع الدقيق: هندسة المعادن
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: تعتبر هذه الدراسة بانها محاولة لتحسين مقاومة التاكل للصلب المقاوم للصدا من نوع 304 عن طريق الانصهار السطحى بالليزر. تم استخدام تقنية منحني تافل لتحديد معدلات تاكل الصلب المقاوم للصدا نوع 304 في محلول 3.5? كلوريد الصوديوم عند اربعة حالات مختلفة. الاولى بدو | The present work represents an attempt to improve corrosion resistance of sensitized 304 stainless steel by laser surface melting treatment. Tafel extrapolation technique was used to determine the corrosion rates of stainless steel type 304 in 3.5% NaCl in four conditions. The first condition is as received, the second sensitized microstructures at temperatures 850 oC for one hour, the third condition is treating the stainless steel alloy by laser surface melting (LSM) without sensitization. The fourth condition is studying the effect of LSM on sensitized stainless steel.The main results obtained are expressed in terms of corrosion parameters through electrochemical behavior : E°, I°, E Corr., ICorr., EP., IP, EPit. and IPit.These parameters are strongly dependent on the microstructures of the alloy. The results reveal when the potentials increase, this means that the microstructure becomes thermodynamically more stable and has good corrosion resistance. The above electrochemical parameters for sensitized 304 stainless steel show that localized corrosion rate increases due to precipitation of chromium carbides on grain boundaries and to the sensitization process affecting the phases. The LSM treatment shifts the potential toward noble direction, the corrosion current densities values shift to lower values. Generally, a change in surface hardness shows a microstructure modification in metallic bonds. The comparison of anodic polarization curves indicates that the corrosion rates for laser treated specimens are reduced. Increase in corrosion resistance probably means that most inclusions at the surface have been dissolved in the structure due to melting or alternatively, they are covered by molten materials. An interesting feature is the systematic shift of the pitting potential in the noble region with a laser treatment. This result confirms that the laser treatment can be used successfully to improve the localized corrosion resistance.

المعاملة السطحية بالليزر لحديد الزهر الرمادي باستخدام ليزر (Nd : YAG - Nano Second) == Laser Surface Heat Treatment For Gray Cast Iron Using Nano Second Nd : YAG Laser

اسم المؤلف: بلال احمد حبيب
اسم المشرف: رابحة صالح ياسين | هجران زين العابدين طعمة
السنة: 2014
الموضوع الدقيق: هندسة المعادن
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: في هذا البحث، تم استخدام تاثير معلمات الليزر لتحسين الخواص السطحية للحديد الزهر الرمادي، وذلك باستخدام جهاز Nd : YAG ليزر بطول موجي nm(1064 (، البعد البؤري cm( 5 ,10,18)، وامد النبظة ns (10). استخدمت طريقة الانصهار السطحي بالليزر في تصليد العينات، الى | In this thesis , the effect of laser parameters is used for perfection of the surface characteristics for gray cast iron , using pulsed Nd : YAG laser with wavelength of (1064nm ).The laser surface glazing and shocking methods have been used in hardening the specimens , besides using the laser energy in treatment of (1.2 J) , pulse duration (10 ns), with different focal length of (5,10,18) cm and used the (air ,water , DMSO) as a active medium. In laser surface engineering the micro hardness, roughness and wear rate examinations deliberated before and after laser treatment. The effect of laser parameters includes : The effect of the pulse repetition rate (P.R.R) , the result shows , thevalue of the micro hardness of work pieces reduced but the variation in the value hardness decreased. For the effect of the medium used (air, water, DMSO) it was found with increasing the water and DMSO high the value of the micro hardness of work piece increased and value of the (loss of weight , wear rate, surface roughness ) reduced. After treatment by laser the amount of loss in weight is less than the loss of weight with the base metal (before the treatment) , so the results reveal an improvement in wear rate after treatment by laser. And for the effect of overlapping technique ,it was found that the best percentage for overlapping technique ratio is 50% for the selected laser energy. The value of micro hardness increased by moving away from the center of the laser strike on the work piece.

الحماية من التاكل لقواعد الاعمدة الكهربائية في الترب ذات المقاومية المنخفضة == Corrosion Protection of Electrical Bar Stands In Low Resistivity Soil

اسم المؤلف: اياد نصيف جاسم
اسم المشرف: سامي ابراهيم جعفر الربيعي
السنة: 2014
الموضوع الدقيق: هندسة المعادن
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: يستخدم الفولاذ المغلون في تصنيع الاعمدة الكهربائية لامتلاكه خواص ميكانيكية جيدة ومقاومة تاكل عالية. وتحت الظروف الاعتيادية يعاني العمود من التاكل بعد عدة سنوات من الخدمة.يصنع عمود الكهرباء من فولاذ St - 52 والمطابق للمواصفة DIN الالمانية ويتالف من ثلاثة | Galvanized steel is used in electrical poles because of the good combination of its mechanical properties and the corrosion resistance. Under normal conditions, electrical pole suffered from corrosion after some years in service. Electrical poles, which were made according to Germany standard DIN st.52, consist of three parts; the upper, mid and lower part. This study focuses on the last part because the surrounding soil of electrical pole is more corrosive than the atmospheric environment, which surrounds to other two parts of the electrical pole. Soil resistivity is the one variable that has the greatest influence on corrosion rate. Electrical poles which at buried in low resistivity soils will generally be anode, whereas electrical poles buried in adjacent high resistivity soils will generally low corrosion.The electrolyte in this work was prepared according to the values of Iraqi soil resistivity. Sodium chloride (NaCl) was used in different concentrations of (2, 2.5, 3 and 3.5) wt. %, which are equivalent to 27, 24, 20 and 18 ohm.cm. Two methods were used in this work in order to improve corrosion resistance, the first method galvanizing process in different thicknesses (80, 90,100,110,120 and130) µm and the second method is coating by different types of Iraqi paints (D - 5547) with hardener (H - 1457)and(G - 5532,G - 5533,D - 5542) with hardener(H - 5533) The corrosion rate and corrosion potential of steel increases and decreases with the increase in NaCl wt.% concentration respectively. Corrosion rates (mpy) with coating thickness are achieved as a function of environment in different soil resistivities. The more corrosion resistance occurs at 120 µm galvanized layer. Micro cracks appear at 130 µm galvanized thickness.In this work, two mixed ratios of paint and hardener were used. These ratios are 2 : 1 and 1 : 1. Paint with mixing ratio equal to 2 : 1 of G - 5532 + G 5533and mixing ratio 1 : 1 D 5542 with hardener 5530 gave the more corrosion resistance.The coating thickness has a direct influence on the performance or life of the electrical pole. As the thickness of galvanized layer increases, the life of protection increases until 120 µm. The life of a zinc coating is a linear function of coating weight for any specific environment. The efficiency of coated electrical pole either by galvanization or paint process was a proximately between 94% to 97% and 98% to 99.6% respectively.

سلوك المواد فائقة اللدونة ذات البنية المجهرية الناعمة لسبيكة المغنيسيوم نوع AZ31B والمشكلة بواسطة التشكيل العالي الانفعال == Superplastic Behavior of Fine Grained AZ31B Magnesium Alloy Processed By Severe Plastic Deformation

اسم المؤلف: زياد طارق عبد الوهاب
اسم المشرف: ازل رفعت اسماعيل
السنة: 2014
الموضوع الدقيق: هندسة الانتاج
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: Superplastic properties and microstructure evolution of commercial AZ31B magnesium alloy processed by two different severe plastic deformation methods Equal Channel Angular Pressing (ECAP) and Equal Channel Angular Rolling) ECAR) were studied. Samples were tested in tension at temperature of 623 K and strain rate ranging from 2.4×10 - 4 1×10 - 2 s - 1. ECAP die with 10 ×10 mm cross section channel, oblique angle of ?=90° and ?=13° was designed to refine the alloy microstructure at temperature of 473 K using route BC. Application of ECAP showed a remarkable grain refinement for AZ31B Mg alloy from 14.1 to 2.1?m after three ECAP passes. Maximum superplastic elongation of 261% was achieved at 623 K and strain rate of 2.45×10 - 4 s - 1. The measured strain rate sensitivity was m = 0.33 demonstrating that viscous glide control creep was the dominant deformation mechanism. In most investigation used ECAR process, the die temperature was set to room temperature, in order to avoid cracking intermediate annealing was used for AZ31B Mg alloy which has poor formability at room temperature. This is caused by a lack of active slip systems, especially in the <c+a> direction. However, in this study a special isothermal ECAR die capable of operating without intermediate annealing was used to process AZ31B Mg alloy. The ECAR was carried out at 623 K using a die of ?115 ° channel angle and without rotation. Processing by ECAR showed less effect on the microstructure refinement where the grain size was reduced from 10?m to 4.2?m after six ECAR passes. ECAR increases the yield and ultimate stress and decreases the elongation corresponding to increasing the number of ECAR passes, the as - received material exhibits large amount of superplastic elongation compared to ECAR processed specimens. Therefore superplastic behavior of the AZ31B magnesium alloy was evaluated at temperatures 623 K and strain rate ranging from 7.8×10 - 4 s - 1? 1×10 - 2 s - 1. The test showed that maximum elongation of 367% can be achieved at 623 K and strain rate of 7.8×10 - 4 s - 1. The strain rate sensitivity (m) was evaluated by two different methods, uniaxial tensile test on the basis of the true stress true strain curve and by strain - rate jump test. The results show small differences between the two method) m = 0.42 - 0.45), which demonstrate that the grain boundary sliding (GBS) is the dominant deformation mechanism during superplastic test Keywords : Superplasticity. Severe plastic deformation. AZ31B magnesium alloy.

نظام ذكي لتقييم الخشونة السطحية لعملية تشكيل الصفائح التزايدية == Intelligent Surface Roughness Evaluation System of Ismf Process

اسم المؤلف: اوس خالد ابراهيم
اسم المشرف: وسام كاظم حمدان
السنة: 2014
الموضوع الدقيق: هندسة الانتاج
الدرجة: ماجستير
اللغة: الانكليزية
مكان الجامعة: بغداد
الصفحات الاولى:
المستخلص: تعد عملية تشكيل الصفائح التزايدية تقنية حديثة نسبيا لتشكيل الصفائح المعدنية والتي توفر امكانية تصنيع اجزاء معقدة الشكل وذلك باستخدام مكائن التفريز المبرمجة (CNC milling machines) بدون الحاجة الى قوالب خاصة لكل منتج والتي تتطلب وقتا طويلا للتصنيع مقارنة مع | Incremental Sheet Metal Forming (ISMF) is a modern sheet metal forming technology which offers the possibility of manufacturing 3D complex parts of thin sheet metals using the CNC milling machine. The surface quality is a very important aspect in any manufacturing process. Therefore, this study focuses on the surface quality of parts produced by single point incremental forming (SPIF) process. As a consequence, the objective of this study is to control the surface roughness by studying five forming factors, namely; (tool diameter, step size, tool shape, rotational speed and slope angle).In order to evaluate the surface quality, practical experiments for forming pyramid like shapes have been carried out on sheets of aluminum AA1050 with thickness 0.9 mm. As a result, two Adaptive Neuro - Fuzzy Inference systems (ANFISs) are conducted for predicting the surface roughness. The first system depends on the five forming factors as a direct contact estimation method while the second system utilizes contactless parameters (average gray level, standard deviation and mean frequency) that are extracted from the products images using a vision system as a contactless prediction method. A third model is developed using Sugeno Fuzzy Inference System (SFIS) for the evaluation of forming factors by which the surface roughness for a certain slope angle is obtained.Both quantitative and qualitative assessments have been used to explore the effects of the five forming factors on surface quality of parts produced by SPIF process. The ANOVA and MEP results show that the incremental step size and the forming tool shape are the most important factors affecting the surface roughness. These two factors are directly and inversely proportional to the surface roughness respectively. The maximum and minimum surface roughness, which is achieved from all the 24 experiments is (Ra = 4.3 & Ra = 0.18 µm) respectively. As a result, a surface with roughness smaller than the initial roughness of the sheet (0.27 µm) has been obtained. The qualitative assessment reveals that the surface roughness tends to increase towards the part deep.It can be concluded that the image based estimation of roughness using ANFIS is superior in terms of prediction accuracy. This vision system can achieve (97.856%) testing prediction accuracy compared to (85.799%) that is reached by the direct contact estimation of roughness. Conclusions also show that the vision system is capable of predicting the surface roughness of a hyperboloid part as a non - linear shape with prediction deviation (14.411%), thus enabling to evaluate the surface quality of complex parts that cannot be measured by the stylus. It can also be concluded that the SFIS is a successful approach for estimating the forming factors by which the surface roughness for a particular slope angle is obtained.
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