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EFFECT OF POURING TEMPERATURE AND DEGASSING ON THE CASTING QUALITY OF Al 6061: EXPERIMENTAL AND NUMERICAL STUDY
Get PDFAs one of important components of an airplane, body of airplane is required to have high value of strength to weight ratio. In this study, transient heat transfer of Al 6061 in a sand casting process was investigated both experimentally and numerically. The effects of different pouring temperatures (700, 720 and 740 °C) and presence of thin film and H2 inclusions are considered in the present study. Composition, XRD, metallography and tensile strength tests have been carried out to examine the casting product quality, before and after degassing, a process to remove the inclusions from the cast. Correspondingly, heat transfer simulations were carried out by taking into account the variation of pouring temperatures and the presence of inclusions. From the present experimental and numerical study, it was found that: (i) Degassing enhanced significantly the strength of Al 6061 product. The highest tensile strength value has been found to be 64.30 MPa, related to the pouring temperature of 700 °C with degassing, while the lowest one is 35.85 MPa associated with the pouring temperature of 700 °C without degassing. (ii) Pouring temperature did not affect significantly to the strength of Al 6061 product, especially when degassing process was carried out, and (iii) The presence of thin film and hydrogen gas inclusions affected the cooling rate of the metal slab. Overall, the cooling of the metal slab with thin film inclusion became slower, while the cooling of the metal slab with hydrogen gas inclusions became faster
Evaluasi Keutuhan Borepile Metode Crosshole Sonic Logging (CSL) Pembangunan Jembatan Pulau Balang II
Get PDFThe problem that occurs in the Balang II Island Bridge construction project in East Kalimantan Province is the blockage of concrete flowing through the tremi pipe when casting the borepile foundation at sea. A considerable distance from the initial location of the tremi pipe (on land) to the endpoint of casting requires a fairly long tremi pipe. This blockage causes the concrete to flow imperfectly. There are many speculations about the cause of this problem, including leaks in the tremi pipe and the uniformity of the concrete mix. Based on these problems to prevent the failure of the foundation structure, an integrity test will be carried out on non-destructive piles. The integrity test to be carried out is in the form of a Crosshole Sonic Logging Test (CSL). The results of the CSL test on pylon P1 show that of the 17 borepile piles tested 2 piles have abnormalities, namely the P1-64 pile with the P/D category on the whole cross-section and the P1-52 P/F category on some sections (± 40%). Overall it can be concluded that the integrity of the drill pile on pylon P1 is still quite safe
Analisis Model Pengaruh Penyebab Terjadinya Waste Terhadap Peningkatan Biaya Konstruksi Gedung Bertingkat Rendah di Jakarta
Get PDFPenyebab terjadinya waste terhadap peningkatan biaya yang dikeluarkan oleh pihak kontraktor sehingga mengalami kerugian dari material yang berlebih atau pun terbuang pada proyek konstruksi. Tujuan dari penelitian ini yaitu untuk menganalisis model pengaruh penyebab terjadinya waste terhadap peningkatan biaya konstruksi gedung bertingkat rendah di Jakarta. Penelitian ini dikumpulkan dari 14 (empat belas) proyek yang berbeda dengan jumlah terkumpul dari 84 responden. Teknik pengambilan sampel dengan menggunakan teknik probabilitas random sampling, sedangkan untuk pemilihan sampel menggunakan simple random sampling.Variabel bekisting,pembesian, pengecoran dan pembongkaran bekisting berpengaruh terhadap peningkatan biaya konstruksi, sedangkan variabel yang paling dominan mempengaruhi peningkatan biaya konstruksi adalah variabel pekerjaan bekisting dan pekerjaan pembongkaran bekisting. Peningkatan biaya konstruksi diperoleh dari indikator yang memiliki skor tertinggi yaitu pada Variabel pekerjaan bekisting untuk indikator X1.4 dengan persentase 0,94% dan Varibel pekerjaan pembongkaran bekisting untuk indikator X4.4 dengan persentase 0,97% yaitu “Pengawasan pemasangan bekisting kurang insentif”dan“Metode pembongkaran yang kurang tepat” dengan skor total 341 dan rata-rata 4.059 dengan nilai persentase dalam kategori yang baik sekali.
Satisfaction and Loyalty of Banking Customers in Indonesia
Get PDFImproved customer satisfaction and loyalty are essential metrics in increasing a company's revenue and profit in the banking industry. This research aims to determine the effect of satisfaction on loyalty among bank customers in Indonesia. The study was conducted by face to face interview method (F2F) among 1910 bank customers in eight metropolis in Indonesia (2019). The sampling method used a random sampling followed by a booster sampling approach. The analysis was conducted using the Structural Equation Modeling (SEM) by WarpPLS approach. The results show that satisfaction positively and very significantly affects loyalty
Numerical Study of B-Screw Ship Propeller Performance: Effect of Tubercle Leading Edge
Get PDFVarious attempts to modify the ship's propeller have been made to improve performance as a propulsion component. This paper analyzes the effect of modification of the B-Series propeller by adopting a whale fin shape (Humpback Whale). Also, it analyzes the flow in the propeller before (standard) and after modification. Modifications are made to the leading edge, which is called the tubercle leading edge (TLE). It adds and subtracts sections with a wavelength of 0.2R and amplitude of 2.5% of the chord section length in the propeller leading edge. The numerical study is used using CFD on different J values (0.2, 0.4, and 0.6). It was found that the modification of TLE has a less significant effect on performance. Instead, it decreased at a low J value (0.2). Meanwhile, the largest decrease was at a high J value (0.6), namely up to 10.4% for thrust, 4.3% for torque, and 6.4% for efficiency. Whereas at J=0.4, the torque increases only 0.4%, and the torque and thrust decrease, although less significant. The flow analysis indicates that the shape of the TLE provides a decrease in pressure. However, on the positive side, this modification provides a reduction in noise on the propeller surface
Dampak Perubahan Penggunaan Lahan Terhadap Besaran Stok Karbon di Kota Surabaya
Get PDFKota Surabaya mengalami peningkatan jumlah penduduk sebesar 2,5 juta pada tahun 2000 dan bertambah menjadi 2,8 juta penduduk di tahun 2020, dengan rata-rata laju pertumbuhannya tahun 2000-2010 mencapai 0,62%, tahun 2010-2017 mencapai 0,5%. Sedangkan untuk tahun 2018-2020, laju pertumbuhan penduduk adalah -0.19%. Pertamabahan jumlah penduduk dari tahun 2000-2020 tentunya juga diikuti dengan bertambahnya luas lahan terbangun. Akibat adanya alih fungsi lahan terbangun ini menyebabkan berkurangnya lahan terbuka hijau, dimana lahan terbuka hijau memiliki peran yang penting dalam penyerapan gas karbondioksida (CO2). Dalam penelitian ini melakukan analisis sejauh mana persentase perubahan penggunaan lahan di Kota Surabaya pada tahun 2000 dan 2020 disertai dengan menganalisa besaran stok karbon yang dihasilkan dari penggunaan lahan di periode tersebut. Untuk itu, sasaran penelitian ini (1) mengidentifikasi perubahan penggunaan lahan pada tahun 2000 dan 2020; (2) menganalisa nilai stok karbon berdasarkan perubahan penggunaan lahan tahun 2000 dan 2020. Dalam menganalisa nilai stok karbon menggunakan rumus dari Kalkulator GRK yang dikembangkan oleh ICLEI-Local Governments for Sustainability. Hasil penelitian menunjukkan persentase perubahan penggunaan lahan dalam rentang waktu 2000-2020 sebesar 0,97%, sementara nilai stok karbon dalam rentang waktu 2000-2020 meningkat sebesar 4,35%, yakni 283.433,5 Ton dan nilai stok karbon di tahun 2020 sebesar 296.323,5 Ton
Evaluation of Human Resource Information System by Using HOT-Fit Model
Get PDFToday’s competitive business environment, many organization give more attention to enhance effectiveness and efficiency of employee. PT Pembangkitan Jawa Bali as a subsidiary of PT PLN (Persero) also continues to improve business processes of Human Resource Management through the application of Human Resource Information System (HRIS). This application has been developed since 2016 and is still implemented 67% of the HRIS PJB model design. This certainly raises questions about the development of HRIS PJB implementation, which is need for an evaluation of the implementation of HRIS PJB applications. HRIS Manager has never conducted an evaluation of HRIS PJB that can strengthen the benefits of its use for employees. Therefore, this study was conducted to evaluate the use of HRIS PJB applications in this case the focus on the Personal Management module in order to assess its usefulness to the needs of users and organizations by using Human Organization Technology (HOT) Fit Model. Primary data were obtained through a survey method by distributing questionnaires to PT PJB employees as application users. Data analysis method used is Partial Least Square using SmartPLS. The results of this study shows the suitability of this application benefits. If there is a gap, alternative solutions are needed to improve and develop applications in the future. Decision making through Borda Count Method is used to get the right solution with the current conditions and can be used as improvements priority and development of HRIS PJB applications for both application managers and management of PT PJB
Analysis of River Shape and River Bank from West Pillar in Sebatik Island to AA2 Pillar Using Multi-Temporal Satellite Imagery and its Influence to Determine Boundary of Indonesia-Malaysia
Get PDFRiver as the boundary is listed in the 1915 Netherland-British Agreement with its Annex Map without any clear coordinates. This is an obstacle in tracing boundaries in the real river because river is dynamic, changes in the river shape and river bank can occur in more than 100 years. Multi-temporal Landsat satellite imagery processed with a combination of bands (color composite) is used to observe the position of the river bank from 1989 to 2019 with visual interpretation and manual digitization. As a result, over 30 years there was a shifting in the Sikapal river bank with an average 10.8 m on the right side (Indonesia) and 13.6 m on the left side (Malaysia). The average shifting of the Tamboe river bank is the right side 19.8 m and on the left side 9.1 m. The shifting is relatively small because around the Sikapal and Tamboe rivers banks are overgrown by mangrove forests which can slow down the rate of erosion. River banks in 1989, 1999, 2009 and 2019 were used as a basemap for delimitation of the Indonesia-Malaysia boundary using a three-stage approach method. As a result, there are differences in the shape of the boundary line although it is small. Furthermore, Indonesia river area increased 13.4 ha and 14,3 ha for Malaysia river area
The Application of Flexibility Concept on East Java’s Art Auditorium
Get PDFEast Java art has a diversity of types and forms of performances. There are types of performances in the form of theatrical and ballet performances. This traditional art performance is intended to convey messages, advice, and past stories. This presentation is presented with various types of art so that between the types of theatrical or dance performances, each has a variety of needs for its stage and capacity. However, the lack of staging facilities is one of the problems that result in reduced artistic activities, so that some traditional arts in East Java are threatened with extinction. In this study, the purpose of this study is to look for patterns of flexibility in the auditorium to meet the needs of East Java art activities. The method used is the observation method. The observation was carried out by observing each type of East Java art activities to be accommodated, namely the type of traditional dance and theater. The selected arts are several art representatives who have the same type of performance. From the results of data analysis it can be concluded that the auditorium can at least adapt to 4 types of spatial configurations: arena, endstage, proscenium, and plaind stage
Characteristics Analysis of the Archimedes Screw Turbine Micro-hydro Power Plant with Variation of Turbine Elevation Angle
Get PDFElectrical energy has become a basic need of modern society, but the supply of electricity has not yet fully met the needs of the community. Many potential energy sources can be converted into electrical energy. One potential of energy sources is water flow which can be used for micro-hydro power plants in remote areas. This study aims to analyze the characteristics of the Archimedes screw turbine of micro-hydro power plant, in particular concerning on variations in the elevation angle of the turbine. Characteristics determination was carried out on a prototype of a micro-hydro power plant using a Brush Less Direct Current (BLDC) generator and two blades of Archimedes screw turbine. The varied turbine elevation-angle was applied, namely 20, 25, 30, 35, and 40o, with a water discharge of 2.64 L/s. The results show that an increase in the turbine elevation angle from 20 to 40o causes an enhancement in mechanical characteristics, i.e. torque and rpm, as well as electrical characteristics, i.e. voltage, current, and electric power. The mechanical and electrical characteristics reach a maximum value at the elevation angle of about 30o, which is 27.87 mW at 1 kΩ load. Furthermore, increasing the elevation angle to become more than 30o causes a decrease in mechanical and electrical characteristics