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"Bekisting merupakan salah satu komponen dalam proyek yang memakan biaya cukup besar. Penggunaan bekisting berbahan woven polyethylene menjadi salah satu alternatif untuk menekan biaya bekisting. Penelitian ini berfokus pada wiremesh yang di gunakan sebagai penguat bekisting berbahan woven polyethylene, khususnya pada tie beam, di mana terdapat berbagai jenis jarak spasi wiremesh dan sudut putar pemasangan wiremesh hingga berbentuk intan. Identifikasi material yang di gunakan di lapangan, pembebanan akibat beton berdasarkan ACI 347-04 dan DIN 18218:2010, dan cara pemasangan wiremesh dan spreader cleats menjadi parameter yang perlu di dapatkan. Perhitungan deformasi akibat parameter tersebut di lakukan dengan bantuan aplikasi SAP2000 untuk memudahkan permodelan. Perbandingan nilai deformasi pada variasi permodelan jarak spasi wiremesh dan bentuk intan wiremesh perlu di bandingkan juga dengan data eksperimen yang telah di lakukan dalam penelitian sebelumnya oleh Novena pada tahun 2019 yaitu eksperimen Evaluasi Kinerja Bekisting Berbahan Dasar Woven Polyethylene pada Struktur Tie Beam dan Pile Cap. Selain itu, penggunaan aplikasi SAP 2000 juga berguna untuk mengetahui variabel yang di duga sensitif terhadap deformasi bekisting woven polyethylene. Variabel sensitif di tentukan dengan menggunakan sensitivity analysis terhadap variabel input pada aplikasi SAP2000, di mana metode yang di gunakan adalah koefisien korelasi Pearson dan analisa regresi.

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Formwork is one of components in the project that requires a large enough cost. The use of polyethylene woven formwork is an alternative to minimize the cost of formwork. This study discusses wiremesh which is used as a formwork reinforcement made from woven polyethylene, especially on tie beams, where there are various types of wiremesh spacing and rotational angles of wiremesh mounting to form diamond shape wiremesh. Identification of materials used in the field, loading using concrete based on ACI 347-04 and DIN 18218: 2010, and how to install wiremesh and spreader cleats are parameters that need to be obtained. Assessment of the required parameters above with the help of the SAP2000 application to facilitate modeling. Comparison of reform values ​​in the variation of distance modeling of wiremesh spacing and diamond shape wiremesh needs to be compared also with experimental data that have been carried out in research previously conducted by Novena in 2019, namely the experiment The Performance Evaluation of Woven Polyethylene on Tie Beam and Pile Cap Structure. In addition, the use of SAP2000 application is also useful for studying variables that are assumed to be sensitive to woven polyethylene formwork deformation. Sensitive variables are determined by using sensitivity analysis of input variables in SAP2000 applications, where it uses Pearson correlation coefficient method and regression analysis."

"Salah satu bahaya yang sering melanda daerah pengembangan lapangan Panas Bumi adalah gerakan tanah. Secara alamiah daerah panas bumi adalah sangat rentan terhadap pergerakan tanah, karena daerah tersebut umumnya didaerah vulkanik, dimana jalur patahan banyak ditemukan dan kegiatan gempa bumi relatif tinggi. Penelitian ini bertujuan untuk mengidentifikasi penyebaran potensi bahaya gerakan tanah dan mengevaluasi tingkat bahayanya terhadap kegiatan pengembangan Panas Bumi didaerah Wayang Windu, Jawa Barat.

Ada enam lokasi potensi bahaya gerakan tanah telah di petakan, menyebar secara tidak teratur di daerah penelitian. Methoda yang digunakan untuk mengevaluasi tingkat bahaya potensi gerakan tanah adalah dengan mengenalisa tingkat ketidakstabilan lereng dari masing-masing lokasi potensi gerakan tanah dan kemuadian mengenalisa tingkat kerugian terhadap property, manusia maupun lingkungan yang mungkin terjadi sebagai akibat gerakan tanah tersebut. Dari hasil penelitian dibuat program yang ter-integrasi untuk pencegahan, mitigasi atau perbaikan dalam rangka mengelola potensi bahaya tersebut.

Daftar bacaan : 26 (1977 - 2002)

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Rock Movement Hazards Analysis at the Wayang Windu Geothermal Development FieldNaturally, geothermal development fields are susceptible to rock movement hazards because the areas are normally developed in volcanic regions, where fault structures are well developed and earthquake occurrence is highly intense. The purpose of this research is to identify the potential rock movement hazards and to assess the potential risk to property, employees, and possibly to the environment at the Wayang Windu geothermal development field, West Java.

Six (6) potential rock movement hazards were mapped, geographically disseminated from the north to the south in the field investigation. The method used to assess the level of potential rock movement hazards was to analyze the slope instability of every single potential landslide that was identified and then evaluate the level of potential loss or vulnerability to property, humans, and the environment associated with the identified potential landslides. From the results of the research, we will make a recommendation to management on the best, cost-effective way to manage the potential hazards.

References : 26 (1977 - 2002)"

"Jakarta dikenal sebagai wilayah pesisir dan wilayah padat penduduk dengan banyak aktivitas ekstraksi air tanah. Penelitian sebelumnya menggunakan Interferometric Synthetic Aperture Radar (InSAR) menunjukkan bahwa wilayah pesisir utara Jakarta mengalami laju penurunan tertinggi. Namun hingga kini, data pengamatan kontinyu untuk memahami distribusi spasial laju penurunan dalam waktu yang panjang di area yang luas seperti Jakarta belum banyak tersedia. Dalam penelitian ini digunakan Citra Sentinel-1 selama 8 tahun di antara November 2014 hingga Juni 2023. Melalui InSAR dapat terlihat distribusi spasial penurunan dalam area Jakarta keseluruhan untuk menganalisis pola penurunan yang terjadi di Jakarta dengan titik-titik area spesifik dalam waktu yang panjang dinamakan displacement time-series. Pengamatan dengan historical satellite imagery memungkinkan untuk dapat menganalisis perkembangan yang terjadi di Jakarta selama tahun pengamatan InSAR dalam kaitannya dengan pola penurunan yang terjadi. Hasil analisis menunjukkan penurunan di Jakarta lebih terfokus di wilayah pesisir utara dengan laju penurunan tertinggi yang kemungkinan disebabkan oleh konsolidasi sedimen. Wilayah timur Jakarta mengalami penurunan yang disebabkan oleh adanya aktivitas konstruksi. Ditemukan pola penurunan menarik yang terdapat di wilayah barat dan pusat Jakarta, dimana telah mengalami perlambatan penurunan secara signifikan setelah tahun 2020. Tersaji sebuah fakta bahwa tidak semua wilayah di Jakarta mengalami penurunan karena wilayah selatan Jakarta terlihat tidak ada penurunan signifikan yang terjadi. Selain memahami penurunan di Jakarta, penelitian ini juga mencoba memahami deformasi yang terjadi di area Sesar Baribis segmen sekitar Jakarta menggunakan data InSAR yang sama dalam waktu pengamatan yang sama dengan analisis penurunan. Hal ini disebabkan masih kurangnya pemahaman terkait aktivitas tektonik di sekitar Jakarta. Jakarta tercatat pernah mengalami gempa merusak yang disebabkan oleh aktivitas Sesar Baribis pada 10 Oktober 1834. Hingga kini, belum banyak penelitian terkait deformasi Sesar Baribis yang telah terbukti aktif dan hanya berjarak ± 12 km dari wilayah paling timur Jakarta. Penelitian sebelumnya menggunakan metode GPS pada segmen sesar yang sama menunjukkan bahwa estimasi slip rate Sesar Baribis berkisar antara 0.4–1.8 mm/year. Dalam penelitian ini, estimasi slip rate Sesar Baribis berkisar antara 0.1–1.5 mm/year. Lokasi sesar yang berada di wilayah kota besar menjadi tantangan dan faktor ketidakakuratan dalam menganalisis dan memahami pergerakan di area sesar ini karena sinyal penurunan muka tanah yang lebih besar daripada sinyal pergerakan sesar. Oleh karena itu, hasil estimasi slip rate tersebut diperlukan penelitian lebih lanjut guna mendapatkan hasil yang lebih akurat.

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Jakarta is known as a coastal area and densely populated area with a lot of groundwater extraction activities. Previous research using Interferometric Synthetic Aperture Radar (InSAR) showed that the northern coastal area of ​​Jakarta experienced the highest rate of decline. However, until now, continuous observation data to understand the spatial distribution of decline rates over a long period in a large area such as Jakarta has not been widely available. In this research, Sentinel-1 imagery was used for 8 years between November 2014 and June 2023. Through InSAR, you can see the spatial distribution of subsidence in the entire Jakarta area to analyze the subsidence pattern that occurs in Jakarta at specific area points over a long period, called displacement time-series. Observations with historical satellite imagery make it possible to analyze developments that occurred in Jakarta during the InSAR observation year about the pattern of decline that occurred. The results of the analysis show that the decline in Jakarta is more focused in the northern coastal area with the highest rate of decline, which is likely caused by sediment consolidation. The eastern region of Jakarta experienced a decline caused by construction activity. An interesting pattern of decline was found in the western and central areas of Jakarta, where the decline experienced a significant slowdown after 2020. The fact is that not all areas in Jakarta experienced a decline because the southern region of Jakarta saw no significant decline. Apart from understanding the subsidence in Jakarta, this research also tries to understand the deformation that occurred in the Baribis Fault area around Jakarta using the same InSAR data in the same observation time as the subsidence analysis. This is due to a lack of understanding regarding tectonic activity around Jakarta. Jakarta is recorded as having experienced a damaging earthquake caused by the activity of the Baribis Fault on October 10, 1834. Until now, there has not been much research regarding the deformation of the Baribis Fault which has been proven to be active and is only ± 12 km

from the easternmost area of ​​Jakarta. Previous research using the GPS method on the same fault segment showed that the estimated slip rate of the Baribis Fault ranged from 0.4–0.8 mm/year. In this study, the estimated slip rate value of the Baribis Fault ranges from 0.1–1.5 mm/year. The location of the fault in a large city area is a challenge and a factor of inaccuracy in analyzing and understanding movement in this fault area because the land subsidence signal is greater than the fault movement signal. Therefore, the results of the slip rate estimation require further research to obtain more accurate results."

"The columns of a building must be stronger than the beams. The aim of this study is to obtain the cause of the long-term deformation difference by shrinkage between the beams and columns of high performance concrete with compressive strength of 60 MPa. This research was done experimentally in Indonesia during 410 days. Specimens measuring 150 mm × 150 mm × 600 mm were used, 3 pieces for the beams and 2 pieces for the columns. Deformation was obtained by using an embedded vibrating wire strain gauge for each specimen. The difference of long-term deformation in columns and beams is in their autogenous deformation behavior. This is because during the autogenous phase, swelling abnormally occurs in the column before shrinkage occurs. The abnormal swelling is caused by the press of its own weight. This phenomenon does not occur in beams. In the age range of 1 to 200 days, the behavior of the beam deformation has a similar pattern to the deformation behavior of the column with a high deformation rate. After that, at 200–410 days, column deformation changes to a very slow deformation rate. Long-term deformation in columns is lower (64%) than in the beams at 410 days age."

"A safety evaluation of the Notopuro dam in East Java was carried out based on a combination of field inspection, instrument evaluation, and slope stability analysis. The small value of field parameters is particularly caused by the influence of condition function such as piping of the dam body and foundation, and stability of dam. The evaluation results were then presented in the form of importance factor (Idam), total risk index (IRtot) and dam safety value (Naman). The Notopuro dam showed an importance factor (Idam) of 240.00, total risk index (IRtot) of 106.61 and dam safety value (Naman) of 55.58, identifying the unsatisfied condition of the dam. The risk index tool shows priority improvement of the Notopuro dam embankment because of the deformation and sliding. The dam needs therefore further investigation as well as design improvement, and rehabilitation of dam has to be carried out as soon as possible."

"Severe plastic deformation (SPD) adalah metode yang digunakan untuk memperoleh baja dengan sifat mekanis yang baik tanpa penambahan microalloyed. Perubahan struktur mikro setelah SPD akan meningkatkan sifat mekanis material dengan penghalusan ukuran butir. Pada penelitian ini digunakan baja karbon AISI 1010 yang di proses menggunakan metode Thermo-Mechanical Control Process (TMCP) dengan pemanasan awal hingga 1100 °C dan pengerolan pada temperatur 650 °C dengan variasi deformasi double pass rolling dan pendinginan udara. Pengamatan struktur mikro menggunakan teknik metalografi dengan etsa nital 2% dan 5%. Pengukuran ukuran butir dengan metode Jeffries sesuai ASTM E-112-96 dan uji kekerasan dengan metode Vickers. Uji korosi menggunakan metode polarisasi dalam larutan NaCl 3,5% sesuai ASTM G5 dan hydrogen charging test. Tujuan dari penelitian ini adalah untuk mempelajari struktur mikro dan kekerasan baja karbon rendah setelah proses severe warm plastic deformation dan ketahanan korosinya terhadap NaCl dan Hydrogen Induced Cracking.

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Severe plastic deformation (SPD) is one method used to get steel with excellence mechanical properties without micro alloyed addition. The structural changes caused by SPD are reflected in improved mechanical properties of metals especially hardness and yield stress by converting coarse grain to ultrafine grained. In this research used low carbon steel AISI 1010 treated with Thermo-Mechanical control process (TMCP) consist of reheating until 1100°C and double pass reverse rolling on 650°C with variation of deformation and air cooling. Metallographic technique implemented in order to observe the final microstructure and 2% and 5% nital etch used to observe final ferrite size and morphologies. Grain size measured using Jeffries methods according to ASTM E 112. Hardness test used Vickers method. Corrosion test worked out using polarisation with NaCl 3,5% as per ASTM G5 and Hydrogen charging test. The main objective of this research is to studying morphology of microstructure and hardness of low carbon steel after severe warm plastic deformation and the corrosion resistance to NaCl and Hydrogen Induced Cracking."

"Medan magnet yang tinggi pada bintang neutron menimbulkan konsekuensi yang menarik, salah satunya adalah deformasi bintang neutron, persamaan koreksi deformasi yang melengkapi persamaan bola Tolman-Oppenheimer-Volkov dapat dihitung dari persamaan medan Einstein dengan memperhitungkan kontribusi magnetik pada persamaan tensor energi-momentum dari materi bintang neutron. Kami melakukan ekspansi multipol pada tensor energi-momentum yang mengandung medan magnet serta ekspansi multipol dari metrik relatif terhadap metrik Schwarzschild, dimana ekspansi multipol dilakukan hanya sampai pada orde kedua. Kami telah menunjukkan bahwa efek deformasi tampak lebih signifikan pada bintang neutron dengan massa kecil. Jika kita melihat pada hubungan radius massa bintang neutron. Bentuk bintang neutron berubah dari bola menjadi oblat, jika massanya menurun dari massa maksimum.

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The high magnetic field of neutron stars leads to interesting consequences, one of which is the deformation of neutron stars, the deformation correction equations that complemented the Tolman Oppenheimer Volkov equations can be calculated from Einstein field equations and included the magnetic contribution on the energy momentum tensor of neutron star matters. Here, the multipole expansion is carried out on momentum energy tensors containing magnetic fields as well as multipole expansion of the corresponding metric around Schwarzschild metric where the corresponding multipole expansions is performed only up to second order. We have shown that the effect of deformation appears more significantly in neutron stars with small masses. If we look on mass radius relation of neutron stars, by decreasing the mass from maximum mass, the shape of neutron stars change from spherical into oblate."

"ABSTRAKSaat ini beredar di Indonesia berbagai jenis kawat ortodonti, antara lain kawat nickeltitanium. Kawat ini menjadi banyak penggunaannya karena memiliki sifat unik yaitusuperelastis dan memory shape. Setiap kawat memiliki karakteristik, komponen alloypembentuk, dan proses pembuatan yang berbeda-beda. Karakteristik yang dimilikikawat termasuk sifat deformasinya setelah kawat diberi beban gaya. Pada kawat nickeltitanium, apabila kawat mengalami deformasi permanen, maka berkurang juga gayadeaktivasi dari kawat untuk menggerakkan gigi geligi. Tujuan dari penelitian ini adalahuntuk mengetahui berapa besar deformasi permanen pada kelima produk kawat nickeltitanium superelastis diameter 0.014 inci yaitu dari produk Ormco, 3M Unitek,Versaden, Ortho Organizer dan IMD Orthoshaped. Penelitian juga bertujuan untukmembandingkan deformasi permanen yang terjadi antar produk kawat dan apabiladiaplikasi pada waktu yang berbeda. Digunakan 25 sampel penelitian, yang terbagimenjadi 5 kelompok kawat (masing-masing memiliki 5 sampel). Semua kawatdipasang pada prototipe penelitian yang didesain agar terjadi defleksi sebesar 7 mmpada bagian tertentu dari kawat. Kawat diaplikasikan selama 336 dan 504 jam.Deformasi kawat diukur menggunakan kaliper digital dengan cara membandingkandefleksi antara kawat baru dengan kawat yang telah diaplikasi (dari produk yang sama).Diperoleh hasil terdapat perbedaan bermakna deformasi permanen antara kelimaproduk kawat NiTi SE saat dibandingkan satu sama lain dan lamanya aplikasi kawatdapat memperbesar deformasi yang terjadi. Urutan nilai deformasi permanen padabeberapa produk kawat berdasarkan nilai yang paling kecil adalah Ormco, 3M Unitek,Versaden, Ortho Organizer and IMD Orthoshaped.

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AbstractThere are many kinds of orthodontic wires in Indonesia, including the nickel titaniumone. This wire become popular since founded because of its unique characteristic(super elastic and shape memory). Each wire has different characters, contains of alloyand manufacturing procedure. Wire deformity is part of wire?s characteristic that needto be consider. In nickel titanium wire, when permanent deformity happened on it, theunloading forces to move the teeth become less. The aim of this research is toacknowledge the value of permanent deformity in 0.014 inch super elastic nickeltitanium arch wire from five different products and comparing each other on a differenttime of application. This research used 25 samples, consist of 5 group (each groupowns 5 samples). All wires were applied on self made prototype which was designatedto make a 7 mm deflection on each side of the wire. Those were applied for 336 and504 hours. After being deflected on the estimated time, the wire was removed from theprototype and then placed in superimposition mode with the new wire from the sameproduct. The gap between those wires is measured by a digital caliper and defined asthe value of wire permanent deformity. As the result, statistically significant, there is adifferent value of permanent deformity between each products and long termapplication could make the wire?s permanent deformity become worse. The list ofwires from the smallest value of permanent deformity is Ormco, 3M Unitek, Versaden,Ortho Organizer and IMD Orthoshaped."