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"Timbunan bertiang merupakan salah satu metode dalam meningkatkan daya dukung tanah lunak ketika dilakukan pekerjaan penimbunan, dimana tanah dasar diberikan perkuatan berupa pondasi tiang. Adapun dengan adanya perkuatan pada tanah lunak ini ternyata dapat mengurangi penurunan yang terjadi. Hal ini disebabkan oleh adanya mekanisme arching effect yang menyebabkan sebagian beban timbunan ditransfer ke pondasi tiang, sehingga tanah lunak mengalami reduksi beban. Penelitian ini merupakan turunan dari penelitian timbunan bertiang, dimana pada penelitian ini akan dianalisis perbedaan antara pondasi tiang yang menggunakan gesekan antara pondasi tiang dan tanah (friction piles) dengan pondasi tiang dengan menggunakan tahanan ujung (end bearing piles), dimana digunakan Program Plaxis 3D Foundation dalam permodelannya. Selain itu, studi ini juga memvariasikan ketinggian timbunan, jarak antar tiang, kekakuan aksial lapisan geosintetik, dan juga susunan pondasi tiang sehingga dapat terlihat pengaruhnya terhadap sistem timbunan bertiang ini. Bahasan dalam penelitian ini mencakup penurunan dan juga prilaku konsentrasi tegangan yang terjadi pada timbunan bertiang, serta pengaruhnya terhadap gaya tarik geosintetik yang terjadi pada pondasi tiang.

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Piled embankment is one of the methods to improve soft soil’s bearing capacity when the embankment construction is done, in which the base soil is given piles as the support. With piles support the soft soil, the settlement of the embankment can be reduced. This is because of the arching effect mechanism which causes some of the loads of the embankment are transfered through the piles, so that the load working on soft soil is reduced. This study is a derivative of piled embankment case study, where this study will analyze the differences of behaviour between the friction piles system and end bearing piles system using Plaxis 3D Foundation for modeling the case. Besides that, this study is also varying the height of embankment, the spacing between piles, the axial stiffness of geosynthetic layer, and the arrangement of piles so that the affection against piled embankment system could be concluded. The discussion of this research concludes the settlements and also the stress concentration behaviour, and also the axial force of geosynthetic layer that occurs in the piled embankment system."

"ABSTRAKEqual Channel Angular Pressing (ECAP) banyak mendapat perhatian untuk pengembangan material struktur ultra fine grain. Tujuan penelitian ini adalah mempelajari pengaruh ECAP terhadap struktur mikro dan peningkatan sifat mekanik paduan Al-Mg. Pada penelitian ini die ECAP yang digunakan memiliki sudut rongga Φ=120o dan Ψ=7 o. Pengaruh rute deformasi ECAP (A, Ba, Bc, C), jumlah pass ECAP dan perlakuan annealing setelah ECAP akan di evaluasi terhadap struktur mikro dan sifat mekanik yang dihasilkan. Pengujian yang dilakukan adalah metalografi, SEM, XRD, uji keras dan uji tarik. Hasil percobaan menunjukkan bahwa dari keempat rute ECAP, rute Bc merupakan rute deformasi yang menghasilkan butiran yang relatif bulat. Hasil uji SEM menunjukkan bahwa ECAP memperkecil ukuran presipitat dan presipitat semakin mengecil seiring dengan penambahan jumlah pass ECAP. ECAP meningkatkan sifat mekanik paduan Al-Mg dan sifat mekanik semakin meningkat dengan meningkatnya jumlah pass ECAP. Annealing pada 100 dan 200ºC setelah ECAP hanya sedikit menurunkan sifat mekanik Al-Mg, tetapi cukup menaikkan elongasi. Sedangkan pada annealing 300 ºC terjadi penurunan sifat mekanik yang signifikan. Proses annealing pada 100 ºC relatif belum merubah ukuran kristalit (sub butiran), akan tetapi dengan naiknya suhu annealing (200 dan 300 ºC) ukuran kristalit semakin membesar.

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ABSTRACTEqual Channel Angular Pressing (ECAP) has received a lot of attention to the development of ultra fine grain structure material. The purpose of this research is to study the effect of ECAP on the microstructure and mechanical properties of Al-Mg alloys. In this study ECAP die having a cavity corner Φ=120o and Ψ=7 o was used. The influence of ECAP deformation route (A, Ba, Bc, C), the number of ECAP pass and annealing treatment after ECAP will be evaluated on the microstructure and mechanical properties produced . The testing was carried out by metallographic, SEM, XRD, hardness test and tensile test. The experimental results showed that among the four routes of ECAP, Bc route was a deformation route that produced relatively equi-axe grains. SEM test result showed that the ECAP reduced the size of precipitates and the precipitates become smaller with the increasing number of ECAP pass. ECAP increased the mechanical properties of Al-Mg alloys and the mechanical properties increased with the increasing number of ECAP pass. Annealing at 100 and 200 º C after ECAP decreased slightly the mechanical properties, but enough to increase elongation. Whereas, annealing at 300 º C decreased significantly the mechanical properties. Annealing at 100 º C had not change the crystallite size (sub-grain), but with increasing annealing temperature (200 and 300 º C) the crystallite sizes became larger."

"Friction-vibration interactions are common but important phenomena in science and engineering. Handbook of friction-vibration Interactions introduces the principles and provides the resources to understand and work with them. A unified theoretical framework includes some of the most important engineering applications. The first three chapters in the book introduce basic concepts and analytical methods of friction and vibration. The fourth chapter presents the general principles on friction-vibration interactions, and also touches on various engineering applications. In the fifth chapter the concepts and methods are extended to some of the most critical engineering applications in high-tech industry, presenting the friction-vibration interaction principle and applications in data storage systems."

"This book covers the rapidly growing area of friction stir welding. It also addresses the use of the technology for other types of materials processing, including super-plastic forming, casting modification, and surface treatments."

"Studi ini mengkaji bagaimana peningkatan perdagangan internasional telah memengaruhi dinamika kesenjangan upah antar jenis kelamin dan share employment di industri manufaktur di Indonesia hingga 2003 hingga 2015. Teori Discrimination Taste oleh Becker (1957) dan menyatakan bahwa perdagangan internasional adalah mekanisme untuk meningkatkan daya saing di pasar sehingga peningkatan perdagangan internasional akan mengurangi kesenjangan upah antar tenaga kerja laki-laki dan perempuan karena diskriminasi bersifat costly untuk industri. Di sisi lain, teori non neoklasik berpendapat bahwa perdagangan internasional berakibat kepada melebarnya ketimpangan upah dikarenakan adanya segregasi pekerjaan diantara skilled dan unskilled labor. Penulis memasukkan ide dari kedua teori ini ke dalam model teori persaingan dan konsentrasi industri dan menguji model tersebut menggunakan data panel dari data survei rumah tangga Sakernas yang digabung dengan data perdagangan dan konsentrasi dari Statistik Industri dari 2003-2015. Perkiraan dari Ordinary Least Square (OLS) dan random effect di tingkat industri menunjukkan bahwa peningkatan daya saing di dalam pasar karena perdagangan internasional membuat tingkat kesenjangan upah di industri manufaktur terkonsentrasi di Indonesia menjadi semakin lebar.

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This study examines how increasing trade in manufacturing industry in Indonesia through 2003 to 2015 have affected the dynamic of the gender wage gap and share employment. The Discrimination Taste theory by Becker (1957) stated that international trade is a mechanism for the competitiveness in the market hence the increasing of trade will decrease the gender wage gap since it is costly for the industry. On the other hand, non-neoclassical theory argues that international trade results in widening wage inequality due to the segregation of work between skilled and unskilled labor. We incorporate these two ideas into a theoritical model of competition and industry concentration and test the model using panel data of Sakernas household survey data merged with trade and concentration data from Statistik Industri from 2003-2015. Estimates from ordinary least-squares (OLS) and random effects regressions at the industry-level indicate that increasing openness to trade is associated with larger wage gaps in Indonesias concentrated manufacturing industries."

"Micro Friction Stir Spot Welding (m-FSSW) merupakan salah satu jenis solid state welding dengan menggunakan non-consumable tool ber-skala mico thicknes material<1 mm) dan memanfaatkan gesekan serta axial force pada prosesnya. Hasil pengelasan yaitu lap-joint pada satu titik. Pada penelitian ini dilakukan pengujian Geometril tool terhadap hasil pengelasan, sehingga didapartkan korelasi antara geometri tool, temperature ,perubahan kecepaatn putar, hasil uji tarik geser dan uji hardness . Dimana semakin tinggi pin maka semakin tinggi RPM,temperature dan uji tarik (berbanding lurus) dimana ketinggian pin < plunge dept (600 µm). Namun Pada tool 4 geometri tool memiliki ketinggian pin 650 µm dan diameter 2.540 mm, sehingga membuat RPM masih di putaran tinggi ,temperatur pada suhu yang rendah dan hasil uji tarik yang belum maksimal (penetrasi hanya dilakukan di pin/Shoulder tidak menyentuk spesimen uji). Pada eksperimen ini peak temperatur tertinggi berada pada tool 3 (shoulder 450) dengan temperature 428.44˚C dengan hasil uji tarik geser yaitu 449.66 N (tertinggi). Pada pengujian tarik geser terdapat mode kegagalan diamati selama TS tes, yaitu mode PF (Pulled Out Nugget) pada seluruh hasil lasan dengan menggunakan tool 1 hingga tool 4. Hasil kekerasan pada geometri tool diketahui bahwa semakin tinggi pin maka hardnes akan semakin besar atau selaras dengan temperature yang terjadi. Namun saat temperatur berada pada suhu 400°C , material AA100 mengalami fully aneling sehingga berdampak pada penurunan hardness pada material hasil lasan (Jaehyung Cho ,2010). Pada hasil uji struktur makro (crossection) terdapat daerah Stir Zone (SZ), Thermo-Mechanically Affected Zone (TMAZ), Heat Affected Zone (HAZ),ParentMetal (PM), Hook dan EXTD zone (pada tool 1,2,3).Dimana daerah SZ (stir zone), terjadi rekristalisasi secara penuh (>350°C) sedangkan daerah TMAZ yang mengalami rekristalisasi sebagian akibat adanya panas dan mengalami perubahan sifat mekanik (250°C-350°C). dan untuk daerah HAZ atau daerah yang terpengaruhi panas namun

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Micro Friction Stir Spot Welding (m-FSSW) is a type of solid-state welding using a non-consumable tool with a mico scale (materialthickness < 1mm), using friction and axial force in the process. The result of welding is a lap joint at one point. This study has a correlation between tool geometry, temperature, rotational speed, tensile shear test, and hardness (Vickers) test. Where the higher the pin have higher the RPM, temperature, and tensile shear test (directly proportional) where the pin height < plunge depth (600 m). However, in tool 4 the geometry of the tool has a pin height of 650 m and a diameter of 2.54 mm so that the RPM is still at high rotation, the temperature is at a low temperature and the tensile shear results are not maximized (penetration is only at the pin/shoulder not touching the specimen). In this experiment, the highest peak temperature at tool 3 (shoulder 450) is about 428.44˚C with the results of the shear tensile test being 449.66 N (the highest). In the tensile shear test, get a failure mode, there is PF (Pulled Out Nugget) on all weld results (tools 1 to tool 4). The results of the hardness on the geometry of the tool are known that the higher pin, get the high hardness or proportional with the temperature that occurs. However, when the temperature is was at 400 °C, this material (AA100) had fully annealed and had an impact on decreasing the hardness of the welded material (Jaehyung Cho, 2010). In the macrostructure test results, there are Stir Zone (SZ), Thermo-Mechanically Affected Zone (TMAZ), Heat Affected Zone (HAZ), ParentMetal (PM), Hook, and EXTD zone (on tool 1,2,3). The SZ region (stir zone), where full recrystallization occurs (>350 °C) while the TMAZ region partially recrystallizes due to heat and changes in mechanical properties (250 °C-350 °C). and for the HAZ region or heat-affected region but not recrystallized (<250 °C)."