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Abstrak :
This paper elaborates on the theoretical background, necessity, and techniques for enhancing the flexural capacity of a T-section member under combined bending and shear. The paper is based on a continuing research program seeking solutions to the design disparities arising from the introduction of new seismic codes and revised earthquake mapping prior to the tsunami and major earthquakes that occurred in South East Asia more than a decade ago. The research considered the application of external reinforcement using fiber-reinforced polymer (FRP) sheets, creating confinement in the shear area, and improving the tensile strength zone. The test results suggested that the methods sufficiently increased the load-carrying capacity to meet the new provisions, but they also showed that the optimum load-carrying capacity was not reached due to debonding of the FRP sheets in the tensile zone. The work was expanded to search for a surface treatment method that could shift the failure mode from debonding to FRP rupture by performing direct shear tests on treated FRP-to-concrete bond surfaces. Using the best surface treatment method, a failed member was straightened, retrofitted, and re-reinforced in terms of both shear and tension. The experimental results showed that the load-carrying capacity of the flexural member not only increased significantly, but the surface treatment methods also overcame the interface debonding problem. This research provides a method for upgrading the flexural capacity of T-section members designed prior to the tsunami and earthquakes of 2004, and it offers a solution for cracked section repair and restoration.

Abstrak :
Magnesium alloy dapat digunakan sebagai implan biodegradable yang bersifat sementara untuk implan tulang dan vascular stents karena memiliki sifat biocompatible dan biodegradable. Tingkat kekakuan yang dimiliki oleh magnesium alloy juga dekat dengan tulang sehingga dapat mengurangi stress-shielding effect. Namun, magnesium alloy memiliki ketahanan korosi yang buruk apabila terkena kondisi lingkungan yang korosif sehingga akan menghasilkan laju korosi yang tinggi dan degradasi yang cepat sehingga akan menyebabkan kegagalan awal pada implan. Masalah tersebut dapat ditingkatkan dengan teknik pemrosesan yang tepat seperti perlakuan permukaan. Salah satu tekniknya adalah deposisi ZrO2 dan HA untuk meningkatkan ketahanan korosi implan magnesium alloy. Proses EPD dilakukan pada tegangan sel konstan 20 V selama 40 menit pada suhu kamar untuk masing-masing larutan ZrO2 dan HA. Hasil penelitian menunjukkan bahwa ketahanan korosi implan magnesium alloy yang dilapisi ZrO2 dan HA meningkat seiring meningkatnya kekerasan dan kekasaran implan magnesium alloy. Mikrostruktur permukaan pada ZK61 yang telah dilapisi oleh ZrO2 dan HA lebih seragam dan merata dibandingkan dengan mikrostuktur AZ31 yang telah dilapisi oleh material yang sama. Icorr optimum yang didapatkan pada ZK61 sebesar 3.02 μA/cm2 dengan laju korosi sebesar 0.15mm/year. Hasil ini juga menyebabkan penurunan laju degradasi magnesium implan setelah proses perendaman pada simulated body fluids ......Magnesium Alloy can be used as temporary biodegradable implants such as bone implants and vascular stent due to its biocompatible and biodegradable properties. The level of stiffness possessed by magnesium alloys is also the closest to bone so that it can reduce the stress-shielding effect. However, Mg-alloy has poor corrosion resistance when exposed to severe conditions which will result in a high corrosion rate and rapid degradation will lead to the early failure of implant. Those issues can be enhanced by appropriate processing techniques such as surface treatment. One of the techniques is the deposition of ZrO2 and HA to enhance the corrosion resistance of magnesium implants. The electrophoretic deposition process conducted at a constant cell voltage of 20 V for 40 min at room temperature for each ZrO2 and HA. The results shows that the corrosion resistance of magnesium implant coated by ZrO2 and HA increase as hardness and the roughness of magnesium alloy implant increases. Microstructure of ZK61 surface after deposition shows that ZrO2 and HA successfully deposited and evenly distributed. ZrO2 and HA coated ZK61 exhibited significantly better corrosion resistance as compared to AZ31 with Icorr 3.02¼A/cm2 and corrosion rate 0.15mm/year, confirmed by the polarization test. This results also lead to the decreasing of degradation of magnesium implant after the immersion process on simulated body fluids.

Abstrak :
ABSTRAK
Telah dilakukan proses surface treatment Thermal Reactive Deposition (TRD) dalam pembentukan lapisan tipis karbida pada substrat baja SUJ2 . Pada proses ini menggunakan metode pack cementation menggunakan campuran serbuk Ferrovanadium dan Ferrochromium sebagai carbide former . Serbuk carbide former dan susbtrat dicampur bersama NH4Cl dan Al2O3 untuk diproses selama 6 jam dalam furnace. Dilakukan 3 variasi temperatur yaitu 900, 950 dan 1000 C untuk mengetahui pengaruh temperatur terhadap ketebalan, kehomogenan, kekerasan dan laju keausan lapisan karbida yang terbentuk. Hasil pengamatan pada mikroskop optik menunjukkan bahwa semakin tinggi temperatur proses, maka semakin tebal lapisan karbida yang terbentuk pada permukaan substrat disertai membesarnya butir baja pada subtrat. Hasil linescan mikroskop elektron SEM juga menunjukkan bahwa semakin tinggi temperatur ,proses laju difusi dari carbide former Vanadium lebih tinggi dibandingkan Krom pada tiap temperatur. Hasil lapisan dikarakterisasi menggunakan difraksi sinar-X XRD menunjukkan bahwa lapisan terdiri dari karbida vanadium dan juga karbida krom. Pada pengujian keras mikro Vickers, dihasilkan kekerasan rata-rata yaitu sekitar 2100 HV dan menghasilkan laju keausan yang hampir identik pula yaitu sekitar 3 x 10-4 mm3/m, yang artinya campuran serbuk FeCr dan FeV mendekati nilai kekerasan lapisan dengan penggunaan FeV sebagai carbide former tunggal yang memiliki kekerasan rata-rata lapisan sekitar 2400 HV.

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ABSTRAK
In the present study, surface treatment on SUJ2 steel by thermal reactive Deposition TRD method was studied. Two different carbide former powders, ferrovanadium and ferrochromium were used with pack cementation method. The process was carried out on steel substrate at temperatures of 900, 950 dan 1000 C for 6 hours. The effects of temperature on layer thickness, homogenity and hardness were studied. The result showed that the higher temperature the thicker layer that formed on substrate surface and it is followed by enlargement of substrate grains. Scanning Electron Microscope SEM linescan shows that at higher temperature, diffusion rate of vanadium and chromium are increase with the note that vanadium has higher diffusion rate than chromium. XRD results shows that layer that formed with this process consists of vanadium carbide and chromium carbide. The average micro hardness of coatings for 3 temperature variations was about 2100 HV and wear rate was about 3 x 10 4 mm3 m. This hardness was approaching hardness value of FeV as single carbide former with a hardness value of about 2400 HV.

Abstrak :
Sifat mampu basah komposit merupakan salah satu kunci utama dalam peningkatan sifat mekanis komposit. Penelitian ini dilakukan untuk mengetahui pengaruh variasi orientasi, kerapatan dan perlakuan permukaan pada serat terhadap sifat mampu basah komposit. Serat yang digunakan adalah fiberglass dan pengukuran sudut kontak dilakukan dengan metode image processing. Hasil pengaruh dari variasi didapatkan dari hubungan variasi terhadap sudut kontak dan waktu pembasahan. Berdasarkan penelitian yang telah dilakukan, orientasi serat 45°/45° menghasilkan sudut kontak yang lebih rendah, namun membutuhkan waktu pembasahan yang lebih lama dibandingkan dengan orientasi serat 0°/90°. Perbedaan sudut kontak mencapai 6 derajat lebih rendah dan waktu pembasahan 20 detik lebih lama pada orientasi serat 45°/45°. Sedangkan untuk pengaruh kerapatan, kerapatan serat 900 menghasilkan sudut kontak yang lebih rendah dan waktu pembasahan yang lebih cepat dibandingkan dengan kerapatan serat 1250. Perbedaan sudut kontak mencapai 5 derajat lebih rendah dan waktu pembasahan hanya 7 detik lebih cepat. Adanya perlakuan permukaan berupa perendaman dengan NaOH 5% mampu menurunkan sudut kontak hinga 25 derajat untuk resin epoksi dan 3 derajat untuk resin poliester tak jenuh serta mempercepat waktu pembasahan 10 detik. Dengan menggunakan resin poliester tak jenuh, sudut kontak yang dihasilkan lebih kecil dan waktu pembasahan yang lebih cepat dibandingkan dengan resin epoksi. ......Wettability of composite is one of key to increase mechanical properties of composite. This research focused on the effect of orientation, density and surface treatment on fiber to the characteristic of composite?s wettability. The fiber used in this research is fiberglass and the method for contact angle measurement is image processing. The result for those variations can be obtained from contact angle and wetting time. According to result, fiber with orientation 45°/45° gives lower contact angle but longer wetting time than fiber with orientation 0°/90°. For orientation 45°/45°, the differences in contact angle reaches 6 degree lower and the wetting time is 20 second longer. In case of fiber density, the sheet with 900 of fiber density 900 has lower contact angle and faster wetting time than the sheet with 1250 of fiber density. The sheet with 900 of fiber density has results that 5 degree lower for contact angle and 7 second faster for wetting time. The surface treatment with NaOH 5% can decrease the contact angle until 25 degree for epoxy resin used and 3 degree for unsaturated polyester used, also accelerate the wetting time until 10 second. The use of unsaturated polyester results smaller contact angle and faster wetting time than using epoxy resin.

Abstrak :
This book is the first attempt to summarize the existing scientific methods and to present new developments and results in this field. First of all, a large array of functional relationships was elaborated and described in details in a voluminous chapter. Beside the strict mathematical optimization methods, an engineering approach is outlined and demonstrated in many worked examples. The essence of this approach is a recognition that, in many practical cases, the optimum is uniquely determined by a particular constraint. The scientific methods of engineering design of wood products are discussed, compared and illustrated with numerical examples. Special attention is paid to the joint elements and, for their easy optimum selection, new similarity equations are developed and illustrated by practical examples. In the last chapter, the general principles of optimum manufacture, interactions among product structure, degree of automation and optimized production technology are discussed. The main woodworking operations are also described and reference is given for optimum selection of their operational parameters. In the Appendix, over 50 colour pictures demonstrate the unique ornamental properties of various timber materials.