Renewable power generation from wind and solar are gaining popularity to overcome energy crisis nowadays. A lot of advancement has been focused on wind power generation instead of fossil fuels that are degrading to the environment since last two decades in order to increase electricity generation, efficiency improvement, reliability and cost reduction. The generator used in windmill can be an induction generator (IG), synchronous generator (SG), doubly fed induction generator (DFIG), radial flux permanent magnet synchronous generator (RFPMSG) and axial flux permanent magnet synchronous generator (AFPMSG). Furthermore, due to the variable speed of wind turbine, a fully rated power converter handles the extracted energy in direct drive systems or a coupled geared system. However, with geared system, the cost of the overall system increased a lot and proved to be rather less reliable. In this regard, AFPMSG are most suitable for the direct drive applications due to its disc shape structure. The design of AFPMSG is derived from the design of RFPMSG. By using the desired value of parameters like power, speed, efficiency, number of phases, frequency, rated voltage and by taking some assumptions, inner and outer diameter of the rotors can be computed using sizing equation. Furthermore, in order to get balance three phase output and suitable winding factor a proper combination of the coils and poles is required. A 1 kW dual rotor single coreless stator AFPMSG, with concentrated winding is designed by using sizing equation in this research work. In order to analyze the characteristics of an electric machine analytical method formed on the solution of Maxwell equations and Finite Element Method (FEM) are used. The FEM results are more reliable as compared to the analytical method. However, FEM take long computation time as compared with the analytical method. This thesis presents a 2D analytical method to calculate the no load voltage of the coreless dual rotor AFPMSG. Furthermore, to decrease the no load voltage total harmonic distortion (VTHD), initial model of the coreless AFPMSG is optimized by using the developed analytical method. The back EMF obtained by using the 2-D analytical method is confirmed by time stepped 3-D FEM for both the initial and xi optimized models. Finally, VTHD, torque ripple and output torque are compared for the initial and optimized models by using the 3-D FEM. It is demonstrated that the VTHD and torque ripples of the optimized model are reduced as compared to the initial model. Optimization by utilizing the 2-D analytical method reduces the optimization time to less than a minute. Furthermore, an AFPMSG model to reduce torque ripple is presented in this thesis. The proposed model uses arc-shaped trapezoidal PMs. The proposed model reduced cogging torque and torque ripple at the expense of lower average torque. Time stepped 3-D FEM is performed and the results are compared with the conventional model. It is demonstrated that the torque ripple of the proposed model is reduced as compared with the conventional model. To further improve the performance of the designed machine with proposed magnet shape, it''s PM shape is optimized. The Latin Hyper Cube Sampling (LHS), Kriging Method and Genetic Algorithm (GA) are introduced and employed in the proposed machine for the optimization. Asymmetric magnet overhang, interpolar separation of PMs and axial height of PMs are considered as the design variable for the optimization. The volume of the PMs is kept equal to the conventional shape magnet volume during optimization. It is demonstrated that the torque ripple of the optimized model is reduced and the average torque is increased as compared with the conventional and proposed models. The optimized model shows improvement in terms of the quality of the torque along with average output torque. The proposed coreless AFPMSG presents a suitable alternative to meet increasing energy demand as compared to the conventional AFPMSG due to its reduced cogging torque and torque ripple and increased output power and torque. The research work presented in this thesis seems to be an attractive option in the field of axial flux machine to be utilized for wind power applications.
مولانا مفتی محمد یوسف بہاری دارالعلوم ندوہ کے تعلیم یافتہ علماء میں مولانا مفتی محمد یوسف صاحب بہاری ایک لائق فاضل تھے، افسوس کہ انھوں نے ۵؍ اگست ۱۹۲۵ء کو بعارضہ فالج لکھنو میں انتقال کیا، وہ ندوی علماء میں فنون ادب عربی میں کامل دستگاہ رکھتے تھے، فراغت کے بعد اپنی زندگی دارالعلوم پر وقف کردی تھی اور اس وقت وہاں وہ ادیب اول کے عہدہ پر ممتاز تھے، باوجود اس کے کہ ان کو دوسری جگہ بیش قرار تنخواہیں ملتی تھیں، تاہم انھوں نے جس خلوص اور ایثار سے تقریباً دس برس مدرسہ کی خدمت کی وہ تعریف و ستائش کی مستحق ہے، وہ نہایت خاموشی کے ساتھ اپنی خدمات ادا کررہے تھے، عربی رسائل میں ان کے مضامین شائع ہوتے تھے، عربی خواں طلبہ کی سہولت کے لیے شبلی بک ڈپو کے نام مصری مطبوعات کی بہم رسانی کا کام بھی انجام دیتے تھے، افسوس کہ ان کی جواں مرگی نے ہماری صف میں ایک ماتم برپا کردیا اور مدرسہ نے اپنے ایک لائق فرزند کے ساتھ اپنے ایک فاضل مدرس کو کھودیا، خدا مرحوم کو جوار رحمت میں جگہ دے، مولوی ابوالحسنات ندوی مرحوم کی وفات کے بعد ہماری برادری میں یہ دوسرا صبر آزما سانحہ پیش آیا ہے، مسلمانوں میں جو قحط رجال ہے اس کو دیکھتے ہوئے، ان نونہالان چمن کی بے وقت پژمردگی کس قدر پُرحسرت ہے۔ حسرت ان غنچوں پہ ہی جوبن کھلے مرجھاگئے (سید سليمان ندوی، اگست ۱۹۲۵ء)
Abstrak Tracer Study pada Prodi S1 Pendidikan Tata Busana merupakan metode yang digunakan pada perguruan tinggi terutama di Universitas Negeri Surabaya yang digunakan sebagai penghubung antara instansi dan stakeholder untuk mengetahui dan menggali beberapa informasi dalam memperoleh umpan balik (feedback) dari alumninya. Umpan balik (feedback) digunakan sebagai bahan perbaikan sistem dan pengelolaan serta menggali informasi terkait keberadaan alumni. Kegiatan tracer study dilaksanakan dengan memberikan pemetaan antara lulusan yang bekerja di berbagai instansi. Keterserapan alumni merupakan bagian dari persentase keberhasilan alumni untuk masuk di dunia kerja sesuai dengan bidang kompetensi yang diperoleh selama melaksanakan studi di perguruan tinggi. Lulusan/alumni dari Prodi S1 Pendidikan Tata Busana yang memiliki pengetahuan, dan keterampilan yang akan dibutuhkan pada saat memasuki dunia kerja, baik itu bekerja pada instansi pemerintahan, swasta maupun berwirausaha. Hasil Tracer Study Program Studi S1 Pendidikan Tata Busana telah menunjukkan bahwa karakteristik lulusan bekerja di bidang pendidikan dan berwirausaha. Sebanyak 23, 3% bekerja sebagai guru atau tenaga pengajar. 41, 7% para alumni bekerja secara mandiri yaitu dengan berwirausaha dan sesuai dengan bidang keahliahnya, selebihnya bekerja pada sektor bidang pekerjaan lain. Waktu tunggu lulusan program Studi S1 Pendidikan Tata Busana menunjukkan bahwa 73% sebelum mereka lulusan kurang dari 3 bulan setelah lulus sudah mendapatkan pekerjaan, artinya tidak perlu menunggu lama bagi lulusan program studi S1 Pendidikan Tata Busana untuk mendapatkan pekerjaan pertamanya Kata Kunci: Tracer study, Lulusan, Jenis Pekerjaan
Along with other oxide ceramics, alumina is an important and widely used industrial material. Its applications include prostheses and dental implants used as bio-medical replacements, wear- resistant components and speedy cutting tools, thermal and electrical insulations and coatings for high temperature use. The effectiveness of alumina for such uses is credited to its excellent corrosion resistance, high hardness, good electrical and thermal insulating properties and high compressive strength. However, regardless of its excellent potentials and properties, its use for structural applications has significantly been limited due to its low-fracture toughness and low- fracture strength. The potential use of carbon nanotubes reinforced ceramic nanocomposites for various engineering applications has unlocked an interesting area of research. In the current work, two kinds of sintering routes, namely pressureless and spark plasma sintering are used for the synthesis of multiwalled carbon nanotube reinforced alumina matrix nanocomposites. The characterization of the resulted nanocomposites is carried out and their comparison with the sintering behavior of monolithic alumina is presented. Two types of composites were prepared by using pressureless and spark plasma sintering techniques both contained 1, 2 and 3 wt% of as-received and functionalized carbon nanotubes. The mixing and dispersion of carbon nanotubes in alumina was done by a novel technique of gas purging sonication. Varying percentages of carbon nanotubes in the composites were compacted using a uniaxial press followed by pressureless sintering at 1600°C in flowing argon with a dwell time of 15 minutes and spark plasma sintering at 1400°C under a pressure of 60 MPa for a holding time of 10 minutes. Pressureless sintered nanocomposites with 1 wt% carbon nanotubes gave 98.5% relative density with no degradation of carbon nanotubes. Moreover, it also resulted in an increase in fracture toughness from 8.1% and 9.4% and Young’s modulus by 5% and 7% when compared to as-received and functionalized carbon nanotube nanocomposites respectively with respect to pure alumina. This investigation has shown that the densification can be achieved without degradation of carbon nanotubes at elevated temperatures in the carbon nanotube-alumina nanocomposites sintered by conventional route. vWell-dispersed carbon nanotube-reinforced alumina nanocomposites have been synthesized successfully having a high density by spark plasma sintering. At 1 wt% functionalized carbon nanotubes addition in alumina, a near full density is achieved that contributes to the improvement in mechanical properties of the nanocomposites. On addition of 1wt% CNTs, fracture toughness values increased by approximately 18.6% and 14% for functionalized and as-received CNT-alumina nanocomposites respectively. However further addition of CNTs up to 3 wt % slightly decreased the hardness and the fracture toughness. Young’s modulus was improved by 6.5% for functionalized and 4% for as-received CNT-alumina nanocomposites over monolithic alumina. Average grain size of monolithic alumina is observed as 2.0 ± 0.5 μm while that of 1wt% CNT-alumina nanocomposite was less than 1 μm. The well-dispersed carbon nanotubes within the alumina matrix enhanced the pullout resistance, bridged the gaps between cracks and held up the crack propagation by using elasticity that lead to improved fracture toughness.