البحث — المستودع الرقمي العراقي

نتائج البحث: 25 من أصل 248

تصميم وتصنيع والتحقق من الخلية الشمسية ذات الصبغة الحساسة للضوء == Design, Fabrication And Verification of Dye Sensitized Solar Cell DSSC

اسم المؤلف: صابرين سمير حسان

اسم المشرف: ثائرة زكريا الطيار

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

السنة: 2014

الموضوع الدقيق: هندسة الالكترونيك

الدرجة: ماجستير

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكهربائية

اللغة: الانكليزية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: Solar cells are considered a promising technology and renewable, in view of increasing in the electro - optical energy. The continual enhancement in solar cell efficiency by searching for new concepts and techniques, which should grow since it is considered as one of the important sources of energy of the future.This work introduces a type of solar cells that employs photosensitive organic dye. These cells use thin membrane of Titanium dioxide material as nanoparticles covered by an organic dye, which absorbs solar energy (like the chlorophyll in green leaves) to be converted into electrons that are injected into the Titanium dioxide layer, which serves as electron collector. In addition, it has an electrolyte solution to compensate for the electrons lost by the organic dye molecules.The cell's positive terminal was prepared from the deposition of a thin membrane of Titanium dioxide, of 22 micrometer thickness on a conductive glass electrode , followed by heat treatment at 450? for 30 minutes. Three organic dyes were used, two of (Cherry juice mixed with Hibiscus and the Berries juice) which were natural dyes, and the other synthetic, the "Eosin" as an industrial dye. Small quantities of Iodine and Potassium Iodide were dissolved in Ethyl Alcohol of 99.9% concentration in order to prepare the electrolyte solution. As to the negative terminal, it was prepared from the deposition of a graphite layer, used in pencils, onto a conducting glass electrode. The final stage involved the assembly of the different prepared cell components and tested.The equipment used in this work included spectrum analyzer for provision of absorption spectra for the three dyes.The cells have been tested by exposure to light of 100W/cm2 to obtain I - V characteristic curve and the greatest current is obtained with the Cherries and Hibiscus cell was 6.205 mA/cm2 and the maximum voltage 0.569 V. As to the Berries dye cell, the maximum current is found 4.35 mA / cm2 and its maximum voltage 0.607 V. The maximum current and voltage for the Eosin dye cell are found to be 1.32 mA/ cm2 and 0.651V.The conversion efficiency for the Cherry and Hibiscus dye cell is found to be 1.9%, the Berries dye cell 1.5% and for the Eosin dye 0.5%.

تمييز قزحية العين باستخدام التحويل الموجي والشبكات الاصطناعية

اسم المؤلف: احمد عز الدين عبد الله

اسم المشرف: هديل نصرت عبد الله

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

السنة: 2014

الموضوع الدقيق: هندسة الالكترونيك

الدرجة: ماجستير

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكهربائية

اللغة: الانكليزية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: التعرف على قزحية العين هي تقنية القياس الحيوي التي تتناول تحديد الهوية على اساس قزحية الانسان. يعتبر تميز القزحية من انواع التكنولوجيا الحيوية الاكثر دقة المتاحة اليوم بالمقارنة مع انواع كثيرة من التقنيات البيومترية المستخدمة مثل : مسح بصمات الاصابع، التعر | Iris Recognition is a Biometric Technology which deals with identification based on the human iris. It is considered to be the most accurate biometric technology available today compared with many kinds of biometric technologies used, like Fingerprint scanning, Face recognition, Voice recognition and Hand geometry scanning because it has some advantages, such as uniqueness, stability and high recognition rate etc., makes iris recognition so accurate.In this proposed system, two database systems are used. The first is CASIA database system (version 1.0)(Chinese Academy of Sciences Institute of Automation). And, the second is Real database system by using real persons (each with many images) for recognition through camera Mobile Type of Galaxy Note3. An approach to get more accuracy of the offline iris recognition is composed of many steps : capturing the iris image, determining the location of the iris boundaries, normalization, preprocessed using median filter to remove noise, using wavelet transform for two types of filter, Haar and Daubechies, in order to extract the features and finally using the matching by artificial feed forward neural network with back propagation algorithm (FFBNN) for training and testing iris image.In CASIA system, the iris recognition rate for Haar filter was 84.2% and for Daubechies filter was 92.8%, while in the real system, iris recognition rate for Haar filter was 90% and for Daubechies filter was 98.7%. This means the Daubechies filter is the best in execution time and mean square error from the Haar filter. Finally, efficiency of this system is logical, because the performance measurement of False Acceptance Rates was reasonable. The results and the experiments were implemented by P4 computer and the software package MATLAB (R2011a).