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"New applications for composite materials are being developed at a rapid pace. However, their complex microstructures present considerable challenges for testing and characterization. Researchers must harness a clear understanding of guided elastic wave propagation characteristics so that they may predict the dynamic response of these new composite materials and interpret the ultrasonic nondestructive evaluation of their mechanical properties." "Elastic Waves in Composite Media and Structures presents effective analytical and numerical techniques to study the characteristic features of elastic guided waves in fiber reinforced laminated media. CD-ROM contains executable computer programs, which can be used to simulate different scenarios for designing ultrasonic instruments"

"Elastic rail fastening adalah merupakan sistem penambat rel elastis yang digunakan untuk mengikat rel kereta api ke bantalan, komponen utama dari sistem penambat rel elastis ini adalah Spring Clip. Proses manufaktur dari Spring Clip adalah proses bending dan heat treatment. Di dalam penelitian ini, memanfaatkan energi panas yang tersisa setelah proses bending untuk proses quenching, yang mana proses quenching ini merupakan pengganti dari proses hardening. Tujuan dari penelitian ini adalah untuk meningkatkan efisiensi proses manufaktur Spring Clip. Penelitian dilakukan dengan berbagai variasi waktu heating yaitu: 9, 10 dan 12 detik, variasi media quenching yaitu : air dan oli, variasi temperatur tempering yaitu : 200, 350, 450, 550, 6500C dengan waktu tahan 2,5 jam. Hasil penelitian memperiihatkan bahwa variasi waktu heating 10 detik, media quenching oil dan temperatur temper 450°C, memiliki Clamping force, kekerasan dan deformasi plastis yang baik dan masuk standar DE maupun SNI. Peningkatan efisiensi yang dicapai setelah penelitian ini berhasil adalah 27,78 % ditinjau dari waktu baku, 50,6 % ditinjau dari kapasitas produksi dan 8,6 % ditinjau dari harga pokok produksi. Penghematan energi yang dapat dicapai dengan adanya proses bane ini adalah 2881,617 kJ untuk satu Spring Clip.

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Elastic rail fastening system used to tie up train track to sleeper, main component in elastic rail fastening system is Spring Clip. Manufacturing process in the Spring Clip is bending process and heat treatment process.

In this research, calor energy remained from bending process is used for quenching process, where quenching process is a replacement for process it. The purpose of this research is to increase efficiency manufacturing in Spring Clip process.

Research is done in many variations. Heating time variety are 9, 10 and 12 seconds, quenching media variety are water and oil, tempering temperature variety are 200, 350, 450, 550 and 650°C with holding time 2.5 hour.

The result showed that heating time variety is 10 seconds, quenching media oil and tempering temperature 450°C, own clamping force, hardness and a good plastic deformation and according DE standard or SN1 standard. Increasing efficiency reached after the research succeeds 27.78 % from standard time, 50.6 % from production capacity and 8.6 % from manufacturing cost. Energy saving reached with the new process is 2881.617 kJ for one Spring Clip."

"ABSTRAKAnalisis struktur rangka beton bertulang biasa dilakukan dengan anggapan bahwa balok dan kolom beton dalam keadaan utuh, tidak retak, dan tidak memperhitungkan efek tulangan dalam perhitungan kekakuan atau momen inesia elemen-elemennya. Padahal, balok dan kolom beton retak pada beban layan sehingga momen inersia atau kekakuannya berubah. Perubahan kekakuan ini menimbulkan redistribusi momen ultimate. sehingga momen desain untuk perhitungan penulangan juga berubah. Perlu dikaji seberapa signifikan rediatribusi momen ini dengan analisis struktur rangka beton benulang dengan kekakuan yang dimodifikasi pasca-retak.

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ABSTRACT

Structural analysis of reinforced concrete frame is usually done under assumption that the beams and columns in non-crack stadium and the effect of reinforcement to the moment of inertia or elements stiffness. In fact, the beams and columns crack under service load, so the moment of inertia or stiffness on the elements changes. This stiffness change brings the redistribution of ultimate moment. So the design moment also change. It is necessary to know how significant the ultimate moment redistribution is with the modified stiffness analysis in crack stadium."

"Extended Elastic Impedance method is one of the methods in reservoir characterization, which is used to identify lithology and fluids content. This method is an extension of Elastic Impedance method by changing Sin²θ in Zoeppritz equation with tan χ to get scaled reflectivity equation. χ is angle range between -90° up to 90°. By using proper angle (χ), we can calculate the reflectivity that associates with the log parameter (Gamma Ray, Porosity, Lamda-Rho and Mhu-Rho). To proceeds this scheme we need to derive gradient and intercept from AVO analysis, which is used in Zoeppritz equation to calculate reflectivity volume. The proper angle (χ), which is derived from Whitcombe equation, is 30° for Gamma Ray. While the proper angle (χ) for porosity, mhu-rho, and lambda-rho is 60°, -90° and 15° respectively.The result of mhu-rho and lamda-rho inversion in the target area contain of sandstone and oil in the time depth range of 1545 ? 1573 ms for horizon 1 and horizon 2. Based on seismic inversion, lamda-rho and mhu-rho crossplot analysis we can see that the distribution of reservoir in target area has lamda-rho value between 9050 ? 9300 m/s*g/cc or 25 ? 37 GPa*g/cc and mhu-rho value between 7500 ? 11200 m/s*g/cc or 25 ? 35 GPa*g/cc."

"Telah dilakukan analisis AVO (Amplitude Variation With Offset) dan studi inversi Elastic Impedance pada lapangan Penobscot, untuk mengkarakterisasi dan mengidentifikasi kandungan dan persebaran fluida pada reservoar. Pada implementasinya data seismik pre-stack yang diolah dengan menggunakan analisis AVO dan inversi Elastic Impedance menghasilkan output berupa penampang seperti Intercept (A), Gradient (B), Produk A*B, Scaled Poisson?s Ratio Changed, Near Angle Inverted, dan Far Angle Inverted untuk diinterpretasikan lebih lanjut, sehingga dapat dilakukan karakterisasi reservoar dan diketahui persebaran fluida pada reservoar tersebut. Analisis attribut AVO yang dilakukan pada data lapangan Penobscot termasuk pada anomali AVO kelas III (porous gas-sandstone), dan untuk lebih lanjut lagi maka dilakukan proses inversi Elastic Impedance dengan dilakukannya pengolahan data sumur dan dihasilkan output berupa EI near log dan EI far log sebagai pengontrol proses inversi Elastic Impedance. Selain itu dilakukan juga krosplot antara sumur dan penampang inversi untuk menentukan persebaran fluida pada reservoar. Didapatkan hasil pada penampang inversi EI near, zona gas berada pada nilai 17500 ft/s*gr/cc sampai dengan 22500 ft/s*gr/cc, dan pada penampang inversi EI far, zona gas berada pada nilai 10000 ft /s*gr/cc sampai dengan 15000 ft /s*gr/cc pada top AP2 ( top reservoar) pada rentang waktu 2000 - 2050 ms.

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AVO (Amplitude Variation With Offset) analysis and Elastic Impedance inversion studies in the Penobscot field have been performed, to characterize and identify the content and distribution of fluid in the reservoir. In the implementation, seismic data pre-stack was processed by using analysis of AVO and inversion Elastic Impedance produced output section such as Intercept (A), Gradient (B), Product A*B, Scaled Poisson's Ratio Changed, Near Angle Inverted, and Far Angle Inverted for further interpretation. Reservoir characterization thus can be done and the distribution of fluid in the reservoir can be observed. AVO attribute analysis performed on the data field on the Penobscot, was included in class III AVO anomalies (gas-porous sandstone), and the Elastic Impedance inversion process was further performed by the well data processing and the resulting output from the log near EI and EI far as the log Elastic Impedance inversion process controller. Also performed well krosplot between wells and inversion to determine the cross-sectional distribution of fluid in the reservoir. Results obtained in cross section near EI inversion zone, the gas is at the value of 17500 ft / s * gr / cc up to 22500 ft / s * gr / cc, and the cross-section inversion EI far, the gas zone is in the 10000 ft / s * gr / cc up to 15000 ft / s * gr / cc at the top AP2 (top reservoir) in the period 2000 to 2050 ms."

"Presents one of the main directions of research in the area of design and analysis of feedback stabilizers for distributed parameter systems in structural dynamics. Important progress has been made in this area, driven, to a large extent, by problems in modern structural engineering that require active feedback control mechanisms to stabilize structures which may possess only very weak natural damping. Much of the progress is due to the development of new methods to analyze the stabilizing effects of specific feedback mechanisms. Boundary Stabilization of Thin Plates provides a comprehensive and unified treatment of asymptotic stability of a thin plate when appropriate stabilizing feedback mechanisms acting through forces and moments are introduced along a part of the edge of the plate. In particular, primary emphasis is placed on the derivation of explicit estimates of the asymptotic decay rate of the energy of the plate that are uniform with respect to the initial energy of the plate, that is, on uniform stabilization results. The method that is systematically employed throughout this book is the use of multipliers as the basis for the derivation of a priori asymptotic estimates on plate energy. It is only in recent years that the power of the multiplier method in the context of boundary stabilization of hyperbolic partial differential equations came to be realized. One of the more surprising applications of the method appears in Chapter 5, where it is used to derive asymptotic decay rates for the energy of the nonlinear von Karman plate, even though the technique is ostensibly a linear one."