البحث — المستودع الرقمي العراقي

المستخلص: تعتبر الخلايا الشمسية تكنولوجيا واعدة وقابلة للتجديد حيث ازداد الطلب عليها نتيجة لزيادة الاهتمام بالطاقة الكهروضوئية. ان التحسين المستمر لكفاءة الخلايا الشمسية بايجاد التقنيات والمفاهيم الجديدة يجب ان يمتد على نحو متزايد باعتبارها واحدة من اهم مصادر الط | The demand for solar cells has been growing rapidly with an increasing social interest in photovoltaic energy. The improvement of energy conversion efficiency of solar cells is performed by developing the technology and concepts that have been increasingly extended as one of the key components in our future global energy supplement. But, the main problem of photovoltaic modules are their rather high production and energy cost. Three generations of solar cell technologies have been established in the previous century.Nanostructured silicon substrates based on p - type crystalline Silicon (c - Si) have been prepared in this work. Electrochemical Etching (ECE) of the Silicon (Si) wafers in Hydrofluoric (HF) acid was employed to synthesize porous layers consisting of silicon nanostructures. The process was carried out at different etching time and different current densities which are considered as effective parameters in ECE process. It is found that a homogeneous porous layer could be obtained with porosity value of (87%) when the current density is (60 mA/ cm2) and the etching time of (10 min). Among the Transparent Conductive Oxide (TCO) materials available, Zinc Oxide (ZnO) films show promising electrical and optical properties in combination with low cost alternatives. It can function as Anti - Reflecting Coating (ARC), window material, transparent electrode and active layer in heterojunction solar cells. n - type ZnO thin films are grown on p - type nanostructured silicon substrates by using Pulsed Laser Deposition (PLD) technique with Q - switching Nd : YAG laser beam Second Harmonic Generation (SHG) [?=(532 nm), number of pulses (140) pulses, and laser energy (820 mJ)], vacuum of (10 - 3 Torr), ambient oxygen pressure of (10 - 1 Torr), and substrate temperature of (400 °C). The morphological, optical, chemical and structural properties were investigated using Atomic Force Microscopy (AFM), Ultraviolet - Visible (UV - VIS) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and X?Ray Diffraction (XRD) techniques, respectively.Surface morphology and optical properties results show densely packed highly crystalline growth of ZnO thin film on nanostructured silicon substrate grown at optimum condition with an average grain size around (88.57 nm). The average roughness, root mean square, and ten - point height estimated from AFM quantitative analysis, are found to be (3.02 nm), (3.62 nm), and (8.76nm) respectively. The thickness is calculated and found to be (100 nm). The film shows high transparency (above 80%) and the estimated Energy - gap (Eg) is found to be about (3.4 eV). This is important for its applications as transparent conductive films and solar cell windows. The chemical and structural properties results characterize ZnO at (420 cm - 1) and (766 cm - 1) absorption bands respectively and the thin film is polycrystalline with hexagonal Wurtzite structure.

تصميم وتنفيذ ذراع الي موجه عن طريق اشارة تخطيط العضلات باستخدام المتحكم الدقيق == Design And Implementation of A Robot Arm Driven By EMG Signal Based On Microcontroller Unit

اسم المؤلف: انس عبد الحميد كاظم

اسم المشرف: خالدة شعبان رجب

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: تعتبر اشارة (EMG) هي الاشارة المكتشفة على سطح الجلد فوق العضلة والمتولدة من مصدر المجال الكهريائي عند التقلص العضلي. الاشارة العضلية بصورة رئيسية في مجالين : تشخيص الخلل العضلي واشارة تحكم لسياقة ذراع الي، يستخدم الذراع الالي المساق بواسطة الاشارة العضلي | Electromyogram (EMG) is a signal detected on the skin above a muscle and generated by sources of electric field within the muscle during contraction. EMG signal is used mainly in two fields; Muscle disorder diagnostic and control signal for driving robotic arm. The robot arm driven by EMG is used as a remote control in hazard places or as prosthesis part for limbs of disabled. The first part presents placing array of EMG electrode on two muscles and measure the EMG signal, design acquisition circuit to optimize the EMG signal for two muscles; hardware circuit that designed will eliminate the noise resulting from cable, electrodes, 50Hz and aliasing. In order to monitor and record EMG signal, Data Acquisition System (DAQ) is designed for this purpose using Arduino platform, which gives the ability to deal with signal. The real time signal was taken from three persons with different weights and ages. The second part includes a proposed design of digital filter with windowing and applying to real time signal to compare the results for many times of orders and types of windowing in order to meet the best criteria. The FIR filter with 8th order will be chosen as digital filter with Hann windowing that is apply to eliminate the EMG noise that is caused from many sources and results optimum EMG signal that is used to control robot arm, implementing digital filter characteristic into dsPIC30F4013 which it signal processing microcontroller and using the filtered signal to control the robot arm by interfacing with DC driver to drive robotic arm with two degrees of freedom (2 - DOF). Also, this part includes the technique which simulates the results using MATLAB 2011a to control the movements of the robotic arm. Micro C for dsPIC© is used to write C code for FIR digital filter and loops with control algorithm to enable the controlling robot arm.