Design of a Control System for Active and Reactive Power Control of a Small Grid‐Connected Wind Turbine

Reactive power flow between a wind turbine system and the grid is an important issue especially when the wind turbine is connected to a remote grid. In this research, a control system has been developed that allows wind turbine to provide reactive power to the local load connected between the grid and the wind turbine. The supplied reactive power from the wind turbine is controlled by changing the phase angle of Pulse Width Modulation (PWM) in the wind turbine inverter. A proportional controller is used to maintain the reactive power supplied by the wind turbine. Another PI controller is used to maintain the wind turbine operation at an optimum tip speed ratio (TSR) to extract maximum power from the wind. The proposed system along with all sub‐systems has been modelled and simulated in Matlab/ Simulink. The simulation results confirm that the designed system is able to control the wind turbine and capable of providing the required reactive power. Results show that the designed system is able to maintain the system power factor close to unity for a range of wind speeds

Kajian Unjuk Kerja Kelistrikan Arester Porselen Dan Arester Polimer Pada Sistem Tegangan 20 Kv

Pada pengujian arester dalam kondisi kering, nilai arus bocor yang terukur pada arester polimer lebih tinnggi daripada nilai arus bocor pada arester polimer. Tercatat nilai arus bocor pada arester polimer pada pengujian dengan tegangan uji 5 kV sebesar 6.3 μA. Sedangkan untuk nilai arus bocor pada arester porselen nilai tegangan uji yang sama tercatat sebesar 40.5 μA. Untuk pengujian arester dalam kondisi basah, arester diuji menggunakan tegangan 5 kV-20 kV dengan berbagai tingkat pembasahan. Tingkat pembasahan yang digunakan adalah 2.75 – 4.02 liter/menit. Tingkat pembasahan mengacu pada intensitas curah hujan kota Malang. Dalam kondisi basah, nilai arus bocor arester polimer lebih baik dibandingkan nilai arus bocor arester porselen. Pada nilai tegangan uji dan tingkat pembasahan yang sama, nilai arus bocor yang tercatat pada microampermeter sebesar 6070 μA untuk arester porselen dan 38.38 μA untuk arester polimer. Meningkatnya nilai arus bocor pada arester porselen dikarenakan menurunnya nilai resistansi pada permukaan arester. Hal ini disebabkan sifat dari permukaan kedua arester berbeda. Pada pengujian sudut kontak kedua arester, diketahui bahwa arester porselen memiliki sudut kontak sebesar 24.529°. Nilai tersebut masuk dalam kategori hidrofilik. Sedangkan untuk arester polimer sudut kontaknya adalah 109.891°. Berdasarkan perhitungan nilai sudut kontak, arester polimer dikategorikan bersifat hidrofobik atau sifat menolak air.Kunci kunci – arester, porselen, polimer, arus bocor, resistansi permukaan, sudut kontak, hidrofilik, hidrofobik

Monitoring Tetesan Infus Berbasis Mikrokontroler Atmega16

Dalam dunia medis infus merupakan alat yang paling sering digunakan, fungsi infus sendiri yaitu untuk memberikan cairan kepada paisen secara berkala. Kesalahan dalam pemberian cairan infus dapat berakibat buruk kepada pasien, apabila terjadi masalah seperti penyumbatan atau kehabisan cairan jika tidak segera ditangani akan berbahaya bagi pasien. Infus yang ada saat ini penggunaannya masih secara manual dimana kesalahan – kesalahan seperti tersebut masih sering terjadi. Pada tugas akhir ini dikembangkan alat yang mampu mendeteksi kecepatan aliran dan volume cairan pada infus. Terdapat sensor yang mampu mendeteksi adanya tetesan dengan menggunakan perubahan nilai analog cahaya. Perubahan tersebut dikonversi menjadi sinyal digital dengan fitur ADC (Analog To Digital Converter) pada mikrokontroler. Sinyal digital yang diterima mikrokontroler dirubah menjadi besaran dengan satuan tetes per menit. Data tetesan per menit akan ditampilkan pada LCD (Liquid Crystal Display). Buzzer akan bunyi disaat kecepatan tetes lebih lambat 4 tetes/menit atau lebih cepat 4 tetes/menit dari kecepatan yang sudah ditentukan. Alat mampu mendeteksi kecepatan tetesan infus dengan rata-rata nilai error pada konversi satuan sebesar 0,7 %. Penelitian ini menghasilkan suatu alat monitoring tetesan infus yang dapat memberikan informasi mengenai laju kecepatan tetesan dan kondisi cairan pada infus. Sistem yang secara realtime dimonitoring oleh perawat ini dapat mengurangi permasalahan yang timbul karena kelalaian petugas. Sehingga perawat tidak secara manual dalam mengatur kecepatan tetesan infus dan meningkatkan pelayanan kepada pasien

Redesign Project Praktikum Terintegrasi Perancangan Teknik Industri I

PTI Integrated Practicum 1 is a capstone design course in the form of a group project that produces car prototype products whose material is PVC blocks and some material parts are meranti wood. The use of this material has been running for 4 practicum periods. During that period, similar evaluations were identified for each period. Four aspects were obtained as the focus of improvement to improve the quality of PTI-1 products, namely raw materials, design, assembly processes, and machining processes. Based on these aspects, PTI-1 product redesign was carried out using the reverse engineering method, in which benchmarking was carried out at one of the stages. This research resulted in the uniformity of the overall raw material, namely PVC foam, along with a new reference size of 1200 mm x 800 mm for each group. new design constraints with the addition of 10 mm allowance for each size, resulting in a new wheel and axle part design. replacement of latch parts with magnetic catches in the final assembly process to minimize stress and make the assembly process easier, safer, and more precise. Changes to the machining process flow for wheel and axle parts can reduce time waste, with the machining time for all wheel parts being 43.08 minutes and 6.54 minutes for axle parts. The glueing process produces design tools to facilitate the glueing process. The results of the redesign were then analyzed with a product feasibility questionnaire, yielding 97% agreeable results from 14 respondents to Assistant PTI I in 2022. So it can be concluded that the results of redesigning PTI I products can improve the quality of PTI I products in the aspects of raw materials, design, assembly processes, and processing machinery and can be applied in PTI I 2023 practicum courses

Dasar Program Perencanaan dan Perancangaarsitektur (DP3A)Solo Contemporary Library

The library is a place that provides various kinds of information such as a collection of reading books and various printed materials, ranging from science, or culture. In particular, public libraries are libraries that are open to all groups, from children, adults to the elderly and from students, workers or the general public. As time goes by, people began to experience changes in the need for information which resulted in a decrease in interest in reading in the library. This situation becomes the basis for designing a library that is more attractive in today's era and the future, with various supporting facilities provided to increase the interest of users or readers. So that in the design of the Solo City library, it is done by applying Contemporary Architecture, namely the concept of modern, expressive and technological-style architecture. As well as merging the concept of a digital library with a conventional library that aims for effectiveness and convenience. It is hoped that this design can support the productivity of library users and fulfill their information needs

Combined application of foliar fertilizer with basal NPK enhances mulberry leaf yield and silkworm cocoon productivity in calcareous soil

One of the reason of low Mulberry plant (Morus spp.) production in calcareous soils is due to the low efficiency of soil applied fertilizers. Thus, in search of an alternative efficient fertilizer application method, field experiments were conducted at Bangladesh Sericulture Research and Training Institute (BSTRI), Rajshahi, Bangladesh in consecutive two years for achieving higher productivity of mulberry leaf and silkworm cocoon, Bombyx mori L. Four fertilizer management practices such as Control, Basal, Basal + Urea (B+U) and Basal + Foliar fertilizer (FF) were followed for mulberry plant production. Result showed that 3 times FF spray with basal application of NPK (305 kg N, 105 kg K and 66 kg P ha-1 yr-1 in 4 splits doses enhances biochemical constituents in mulberry leaf, leaf yield, silkworm growth as well as cocoon parameters. This study concluded that this treatment was regarded as the best fertilizer management practice which increased the mulberry leaf and cocoon productivity by 17.0 and 52.8 %, respectively over the control. Leaf quality of mulberry in terms of moisture, crude protein, soluble carbohydrate, reducing sugar and total mineral was increased by 14.0, 57.6, 85.8, 140.4 and 60.5 %, respectively in comparison with the control. Thus, foliar spray of foliar fertilizer had a good impact on sericultural productivity

Matrix Models and D-branes in Twistor String Theory

We construct two matrix models from twistor string theory: one by dimensional reduction onto a rational curve and another one by introducing noncommutative coordinates on the fibres of the supertwistor space P^(3|4)->CP^1. We comment on the interpretation of our matrix models in terms of topological D-branes and relate them to a recently proposed string field theory. By extending one of the models, we can carry over all the ingredients of the super ADHM construction to a D-brane configuration in the supertwistor space P^(3|4). Eventually, we present the analogue picture for the (super) Nahm construction.Comment: 1+37 pages, reference added, JHEP style, published versio

Parity nonconserving cold neutron-parahydrogen interactions

Three pion dominated observables of the parity nonconserving interactions between the cold neutrons and parahydrogen are calculated. The transversely polarized neutron spin rotation, unpolarized neutron longitudinal polarization, and photon-asymmetry of the radiative polarized neutron capture are considered. For the numerical evaluation of the observables, the strong interactions are taken into account by the Reid93 potential and the parity nonconserving interactions by the DDH model along with the two-pion exchange.Comment: 17 pages, 2 figure

Mathematically modelling the dynamics of cholesterol metabolism and ageing

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the UK. This conditionbecomes increasingly prevalent during ageing; 34.1% and 29.8% of males and females respectively, over 75years of age have an underlying cardiovascular problem. The dysregulation of cholesterol metabolism isinextricably correlated with cardiovascular health and for this reason low density lipoprotein cholesterol(LDL-C) and high density lipoprotein cholesterol (HDL-C) are routinely used as biomarkers of CVD risk. Theaim of this work was to use mathematical modelling to explore how cholesterol metabolism is affectedby the ageing process. To do this we updated a previously published whole-body mathematical model ofcholesterol metabolism to include an additional 96 mechanisms that are fundamental to this biologicalsystem. Additional mechanisms were added to cholesterol absorption, cholesterol synthesis, reversecholesterol transport (RCT), bile acid synthesis, and their enterohepatic circulation. The sensitivity of themodel was explored by the use of both local and global parameter scans. In addition, acute cholesterolfeeding was used to explore the effectiveness of the regulatory mechanisms which are responsible formaintaining whole-body cholesterol balance. It was found that our model behaves as a hypo-responderto cholesterol feeding, while both the hepatic and intestinal pools of cholesterol increased significantly.The model was also used to explore the effects of ageing in tandem with three different cholesterolester transfer protein (CETP) genotypes. Ageing in the presence of an atheroprotective CETP genotype,conferring low CETP activity, resulted in a 0.6% increase in LDL-C. In comparison, ageing with a genotypereflective of high CETP activity, resulted in a 1.6% increase in LDL-C. Thus, the model has illustrated theimportance of CETP genotypes such as I405V, and their potential role in healthy ageing