Center for Scientific Publication
Not a member yet
4029 research outputs found
Sort by
Numerical Study of Bach-bladed Savonius Wind Turbine with Varying Blade Shape Factor
Get PDFSavonius wind turbine with Bach-profile blades is considered in this study. Previous studies have shown that a rotor with the Bach-profile blade produces better performance than a standard Savonius turbine. This study focuses on the blade shape factor variations of the Bach-profile blade to give the best performance. Two-dimensional unsteady simulations are performed with moving mesh. The configuration being tested is the Savonius rotor with Bach-profile blades with an arc angle of 135◦ . The blade shape factor is varied 0.2, 0.3, 0.4 at a constant freestream velocity of 4 m/s, with a corresponding Reynolds number of 20,000. The k-ω Shear Stress Transport turbulence model was used, with secondorder discretization schemes for the pressure and momentum equations. The boundary conditions were set as velocity inlet for the inlet, outflow for the outlet, and walls for the blade surfaces. The top and bottom sides were set as symmetric. Results showed that the configuration with a shape factor of 0.4 gave the best performance among the others. This configuration gave a higher moment coefficient and power coefficient of about 6.8% and 7.3%, respectively. Results extracted from the simulation includes the flow structure, and the distribution of the pressure coefficients along the blade surface
Pipe Stacking Optimization and Sea Fastening Analysis of Linepipe Transport
Get PDFSubsea pipeline is a system comprised of multiple linepipes that are welded when installed on location used to distribute fluid such as oil and natural gas. Fabricated linepipes are to be stacked on cargo barge and transported to the installation location. This operation takes significant time and involves numerous linepipes. Optimization needs to be done to make sure the transport operation is executed efficiently. Optimization attempt was done using data from Double Joint Linepipe Transport Operation of Tangguh Expansion Project by Saipem Indonesia. Parameters considered during the optimization process include linepipe qualities during stacking, cargo barge strength and stability, and sea fastening property strength. Roark’s Formulas for Stress and Strain formulas are used in pipe stacking analysis to find stacking limit for each type of linepipes. Stability analysis is done by using DNVGL-ST-N001 as a guide and Maxsurf software for modelling. SACS software is used to analyzed sea fastening properties with guidance from DNVGL-ST-N001. Finally, optimization is done using a multi-criteria optimization method by using values from each analysis as parameters. Optimization results find that pipe stacking method using side support is 8.41% more optimal than standard pipe stacking method from Saipem Indonesia
The Impact of the Trans-Sumatran Highway Development on Logistic Cost Efficiency
Get PDFThe development of transport infrastructures of the Trans-Sumatran Highway is the policy of the Indonesian government to boost the economic growth. However, on the other hand, this idea needs to be proven since Indonesia has unique regional characteristics in terms of natural, social, and cultural conditions that bring impacts on congestion, low levels of travel security, and illegal costs or surcharges. This problem triggers inefficient logistics activities which can be seen from the high costs of shipping, transportation, and administrative. Therefore, this paper aims to examine the impact of the Trans-Sumatran Highway construction on logistics cost. The result of this study indicates that there are several benefits obtained from the toll road development. For the manufacturers, they may get a faster shipping process so that inventory turnover is getting higher. High inventory turnover can make inventory costs lower. While for the transporters, faster travel times and smooth toll road conditions can reduce the costs of vehicle maintenance and fuel. In addition, the toll road is able to eliminate the surcharges that previously often arise on trips between Lampung and Palembang. This paper argues that the Trans-Sumatra Highway can enhance the transportation and logistics activities
Sintesis dan Sifat Penyerapan Gelombang Mikro Grafena Alam (reduced graphene oxide) Berbahan Dasar Arang Bambu Kuning (Bambusa Vulgaris), Ori (Bambusa Bambos Miq) dan Petung (Dendrocalamus Asper)
No full textTelah dilakukan sintesis serbuk grafena alam berfasa reduced graphene oxide (rGO) dari arang bambu Kuning (Bambusa Vulgaris), Ori (Bambusa Bambos Miq) dan Petung (Dendrocalamus Asper) sebagai bahan penyerap gelombang mikro dengan metode karbonisasi. Serbuk grafena alam berfasa rGO dikarakterisasi dengan x-ray diffraction (XRD), berupa lembaran tipis berskala mikro dengan tebal ~0,17 µm yang dikarakterisasi dengan scanning electron microscopy (SEM) dan memiliki konduktivitas listrik ~5,5.10-6 S/cm. Grafena alam berfasa rGO memiliki densitas rendah, dielectric loss yang kuat dan specific surface area yang tinggi memiliki potensi menyerap gelombang mikro dengan baik. Penyerapan gelombang mikro pada frekuensi 8 – 12 GHz diukur menggunakan alat vector network analyzer (VNA). Hasil pengukuran menunjukkan nilai maximum reflection loss (RLm) dan matching frequency (fm) serbuk grafena alam berfasa rGO dari arang bambu Kuning, Ori dan Petung secara berturut-turut RLm = -34,15 dB, -45,46 dB dan -52,88 dB dengan fm = 8,40 GHz, 8,40 GHz dan 8,56 GHz pada ketebalan 0,6 mm. Secara literatur penyerapan gelombang mikro dari grafena alam berfasa rGO dari arang bambu Petung lebih baik dibanding dari bahan komersial dan sangat potensial untuk dikembangkan menjadi bahan penyerap gelombang mikro hybrid yang ramah lingkungan.
Studi Pemilihan Moda Kereta Api Eksekutif Dan Kereta Api Semi Cepat Rute Jakarta-Surabaya Menggunakan Teknik Stated Preference
Get PDFThe demand for railroad users, especially executive trains for the Jakarta-Surabaya route, continue to increase every year. The government planned the construction of the Jakarta-Surabaya semi-highspeed train to help the overloaded pantura lane and also as a form to modernize mass transportation. Therefore, study of mode choice between executive trains and Jakarta-Surabaya semi-highspeed train is needeed to analyze and determine the probability of passengers who are willing to shift modes. In this study, data obtained by distributing questionnaires using stated preference and processed using binary logit regression. The results reveal that highest probability occurs in the 3 times a day frequency scenario of 43.32% and for ticket prices of Rp. 900,000 of 75.08%.Permintaan pengguna moda kereta api khususnya kereta eksekutif untuk rute Jakarta-Surabaya terus meningkat setiap tahun. Pemerintah kemudian merencanakan pembangunan Kereta Api Semi-Cepat rute Jakarta-Surabaya untuk membantu beban jalur pantura yang sudah kelebihan beban dan juga bentuk modernsisasi transportasi massal. Studi mengenai pemilihan moda antara kereta api eksekutif dan kereta api semi-cepat rute Jakarta-Surabaya perlu dilakukan untuk menganalisa dan mengetahui probabilitas penumpang yang bersedia berpindah moda. Data dalam penelitian ini didapatkan dari penyebaran kuisioner menggunakan teknik stated preference dan kemudian dianalisis menggunakan regresi logistik biner. Hasil penelitian menunjukkan probabilitas tertinggi terjadi pada skenario frekuensi 3x sehari sebesar 43,32% dan untuk harga tiket Rp.900.000,- sebesar 75,08%
Analisa Kebisingan di Ruas Jalan Arteri Kota Surabaya Serta Korelasinya Dengan Nilai Volume Lalu Lintas
Get PDFSound pollution is a negative impact that occurs from the accumulation of the number of vehicles on a road where vehicles with each other crammed together to be able to drive without slowing down. This study aims to map the value of noise caused by motorized vehicles on arterial roads in the West Surabaya region. As for the method used to do the mapping is the application of geographic information systems based on primary data obtained in the form of vehicle volume and noise values measured by the tool sound level meter, analysis is done using multiple regression and correlation analysis with distribution t. The results obtained from this study are mathematical models of noise on various types of vehicles as well as a correlation model of noise with a degree of saturation. From this study it can be concluded that there is a positive correlation of noise with the degree of saturation where the mathematical model obtained Noise = 137.45 * DS + 34.76, for each increase in the degree of saturation will increase the noise value, in other words the degree of saturation is directly proportional to nois
Pemodelan Faktor-Faktor Yang Mempengaruhi Morbiditas Di Jawa Tengah Menggunakan Regresi Nonparametrik Spline Truncated
Get PDFMorbiditas merupakan angka yang menggambarkan banyaknya penyakit atau keluhan kesehatan dalam suatu populasi pada kurun waktu tertentu. Morbiditas menjadi salah satu indikator yang digunakan untuk mengukur tingkat kesehatan masyarakat. Semakin tinggi morbiditas maka semakin banyak penduduk yang mengalami keluhan kesehatan dan derajat kesehatan masyarakat semakin buruk. Pada tahun 2018 morbiditas di Jawa Tengah mencapai 15,15%. Angka morbiditas tersebut tertinggi di Pulau Jawa dan di atas rata-rata morbiditas nasional yang hanya mencapai 13,91%. Penelitian in idilakukan untuk mengetahui faktor-faktor yang diduga mempengaruhi morbiditas di Jawa Tengah menggunakan Regresi Nonparametrik Spline Truncated. Metode ini digunakan karena pola hubungan antara morbiditas dan faktor-faktor yang diduga berpengaruh tidak mengikuti pola data tertentu. Hasil penelitian menunjukkan bahwa model regresi nonparametrik spline terbaik adalah menggunakan kombinasi knot 2,3,2,3,3,3 dan seluruh variabel yang digunakan dalam penelitian berpengaruh signifikan terhadap morbiditas di Jawa Tengah. Variabel yang digunakan yaitu kepadatan penduduk, persentase penduduk miskin, rata-rata lama sekolah, Upah Minimum Kabupaten/Kota, persentase rumah tangga ber-PHBS, dan persentase penduduk dengan akses sanitasi layak. Koefisien determinasi dari model sebesar 98,45%
Analisis Kebijakan Struktur Tarif dan Pengaruhnya terhadap Besaran Subsidi (Studi Kasus : TransJakarta)
Get PDFKebijakan tarif angkutan umum merupakan komponen dasar yang sangat penting dalam pengoperasian angkutan umum karena tarif merupakan faktor utama dalam menarik penumpang dan sangat berpengaruh terhadap kondisi finansial operator angkutan umum. Penerapan kebijakan struktur tarif seragam/flat fare pada Transjakarta seakan-akan tidak memperhatikan karakteristik pergerakan penumpang sehingga dengan penerapan struktur tarif yang dipengaruhi oleh jarak dapat memberikan peluang untuk menghasilkan revenue yang lebih besar dan berimplikasi terhadap penurunan besaran subsidi. Penelitian ini bertujuan untuk melakukan kajian terhadap pengembangan beberapa alternatif kebijakan struktur tarif yang dapat diterapkan oleh Transjakarta dan kemudian memberikan rekomendasi kebijakan struktur tarif yang dapat berpengaruh terhadap penurunan besaran subsidi dengan tetap memperhatikan kemampuan membayar pengguna dan kenyamanan pengguna atas perubahan tarif yang terjadi. Dalam penelitian ini menggunakan analisis ability to pay dalam penentuan besaran tarif dan menggunakan data tapping Transjakarta pada tanggal 18 Mei 2018 yang diolah menjadi data distribusi frekuensi penumpang sebagai dasar dalam perhitungan revenue Transjakarta untuk setiap alternatif kebijakan yang dirumuskan. Dengan melakukan evaluasi terhadap 7 (tujuh) alternatif yang telah dirumuskan maka diperoleh hasil bahwa kebijakan yang paling direkomendasikan adalah struktur tarif bertahap (sectional fare) dengan kebijakan tarif awal sebesar Rp.3.500 berlaku pada 15 kilometer pertama kemudian berlaku tarif penyesuaian sebesar Rp.1.500 untuk setiap pertambahan jarak 10 kilometer. Kebijakan tersebut menghasilkan penurunan subsidi sebesar Rp.34.476.000/hari atau sekitar 10,71% jika dibandingkan dengan tarif eksisting Transjakarta
Closure
No full textScope of JIFAM PaperJIFAM accepts papers on Infrastructure & Facility Asset Management. The scope of the topic includes, but not limited to the following.- I & F Function- I & F Demand - Supply- I & F User Behavior- I & F Evaluation- I & F Policy- I & F Preliminary Idea- I & F Planning- I & F Design- I & F Construction- I & F Administration Aspects- I & F Technical Certification- I & F Information System- I & F Operation System- I & F Maintenance System- I & F Disposal- I & F Economics & Financial Aspect- I & F Spatial & Environmental Aspect- I & F Sustainability Aspects- I & F Strategic Aspect- Decision Making for I&FAM- Statistics for I&FAM- Mathematics for I&FAM- Operation Research for I&FAM- I & F Managing Organisation Aspec