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"Pemanfaatan besi tuang nodular sebagai material teknik saat ini telah berkembang dengan pesat. Material ini dipilih karena mempunyai sifat mekanis dan fisik (Mechanical and Physical Properties) yang sangat baik, serta dapat menggantikan baja. Salah satu pemanfaatan besi tuang nodular digunakan sebagai komponen otomotif. Pada penelitian ini dicoba untuk meningkatkan sifat mekanis besi tuang nodular FCD-60 ke ADI (Austempered Ductile Iron) dengan menambahkan nikel 1% , molybden 0,15 %, chromium 0,2% serta memberikan perlakuan panas austenisasi 800 dan 900°C waktu tahan 60 menit diikuti austemper pada dapur garam (salt bath) dengan variasi temperatur 300, 400° C dan waktu tahan 15, 30 dan 45 menit. Hasil penelitian pembuatan ADI memperlihatkan peningkatan sifat mekanis dari FCD-60 dengan penambahan unsur paduan komposisi C (1% Ni + 0,15% Mo+ 0,2% Cr), yaitu diperoleh kuat tarik 133,66 Kg /mm2 , kekerasan 548 HB, harga impak 11 J/cm2 serta regangan 6 % diikuti dengan adanya perubahan struktur mikro dari ferrite-pearlite pada kondisi as-cast menjadi bainite dan sedikit austenit sisa pada kondisi setelah austemper. Dilakukan pengujian Ieiah ( fatigue ) FCD-60 untuk komposisi A ( non alloy ), komposisi 8 ( 1% Ni + 0,15 Mo) dan komposisi C ( 1% Ni + 0,15% Mo+ 0,2% Cr ), dalam kondisi as-cast. Pengujian dilakukan dengan mesin uji Rotating Bending Fatigue. Metode pengujian sesuai standard Jl$ 2273 dan ukuran sampel uji sesuai standard DIN 34 ABCHNITT. Data yang didapat dari pengujian ke tiga komposisi tersebut ternyata menunjukkan sifat ketahanan Ieiah semakin meningkat dengan penambahan unsur paduan Nikel, Molybden dan Chomium. Dengan hasil tersebut dapat digunakan sebagai alternatif material Crank Shaft dan komponen lain seperti Roda Gigi serta mencoba mengusulkan proses manufaktur dari ADI khususnya proses perlakuan panas austemper."

"The definition of the physical and mechanicalproperties of sugarcane trash pellets were necessary for the designconsiderations relating to storage, handling andprocessing equipment. The mixing ratios of groundsugarcane trash:cassava starch:water content (1.0:0.25:0.85 and 1.0:0.25:1.40 by weight) and pelleting speeds (100, 120, 140, and 160 rpm) were considered to determine their effects on bulkdensity, true density, porosity, durability and compressive strength. The results show that the mixing ratio byweight of 1.0:0.25:0.85 and pelleting speed of 120to 140 rpm were optimum for producing the sugarcane trash pellets. At the moisture content of 12.01% (wb), the bulk density, true density, durability and compressive strengthof biomass pellets were in the range of 330.93 to 365.00 kg/m3, 860.38 to 918.43 kg/m3, 99.34 to 99.46 % and 5.15 to 6.43 MPa, respectively."

"ABSTRAKMaterial perovskite menjadi menarik untuk diteliti karena sifat fisis, relasi kompleks antar sifatnya, dan potensi dalam aplikasi elektronik. LaFeO3 adalah salah satu jenis material perovskite orthofferite yang menarik perhatian karena potensi aplikasinya material elektroda pada SOFCs dan sensor dan relasi kompleks antara sifat listrik dan magnetnya. Beberapa penelitian sebelumnya memperlihatkan bahwa doping pada LaFeO3 mempengaruhi sifat-sifatnya, khususnya sifat struktur dan listriknya seperti kestabilan struktur, kenaikan dielektrik konstan, penurunan loss dielektrik, kenaikan konduktivitas, dll. Pada penelitian ini, kita fokus pada pengaruh substitusi Mo pada Fe-site pada LaFeO3 terhadap sifat struktur, vibrasi, dan listrik. Proses sintesis material akan dilakukan dengan metode solgel-sintering menghasilkan nanopowder dan nanocrystal bulk . Sifat struktur dikarakterisasi dengan X-ray Diffraction XRD . Hamburan Raman dikarakterisasi dengan spektroskopi raman sebagai fungsi temperatur pada rentangan 300K ndash; 500K untuk menjelaskan tentang sifat struktur, paramter struktur, dan transisi magnetik. Energi gap diperoleh dari karakterisasi spektroskopi elipsometri. Sifat listrik konduktivitas dan dielektrik dikarakterisasi menggunakan RLC-Meter dan dianalisis menggunakan metode spektroskopi impedansi dan parallel plate method. Sifat termal dikarakterisasi menggunakan differential scanning calorimetry DSC untuk mengidentifikasi keberadaan transisi fasa yang dikonfirmasi oleh hasil karakterisasi raman.Keyword : Perovskite, LaFeO3, sifat fisika, transisi fasa.

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ABSTRACTPerovskite materials have been intensively studied and also attracting a great interests due to of their physical properties, complex correlation in properties, and potential electronics applications. LaFeO3 is one of orthoferrite perovskite material which paid attention in decades because its potential application and complex correlation between electrical and magnetic properties. Several researches shows that doping on LaFeO3 has led to physical properties, especially structural and electrical properties such as stable structure, higher dielectric constant, low dielectric loss, higher conductivity, etc. In this study, we focus on Mo substitution in Fe site of LaFeO3 and studing about structural, vibrational, and electrical properties as comparative study. The synthesize have been done by sol gel sintering method resulting nanoparticle powder and nanocrystalline bulk samples. The structural properties is checked by XRD. The vibrational properties is recorded by Raman scattering measurement as a function of temperature in the temperature range of 300K ndash 800K. The gap energy was obtain by ellipsometry spectroscopy. The electrical properties conductivity and dielectric were characterized by RLC Meter and analyzed by complex impedance spectroscopy and parallel plate method. Thermal properties was characterized by DSC to identify the phase transition and consistent with raman results. Keyword Perovskite, LaFeO3, physical properties, phase transition"

"The definition of the physical and mechanical properties of sugarcane trash pellets were necessary for the design considerations relating to storage, handling and processing equipment. The mixing ratios of ground sugarcane trash:cassava starch:water content (1.0:0.25:0.85 and 1.0:0.25:1.40 by weight) and pelleting speeds (100, 120, 140, and 160 rpm) were considered to determine their effects on bulk density, true density, porosity, durability and compressive strength. The results show that the mixing ratio by weight of 1.0:0.25:0.85 and pelleting speed of 120 to 140 rpm were optimum for producing the sugarcane trash pellets. At the moisture content of 12.01% (wb), the bulk density, true density, durability and compressive strength of biomass pellets were in the range of 330.93 to 365.00 kg/m3, 860.38 to 918.43 kg/m3, 99.34 to 99.46 % and 5.15 to 6.43 MPa, respectively."

"Beton merupakan istilah yang tidak asing lagi bagi setiap orang, digunakan untuk menyatakan campuran antara semen, air, pasir dan kerikil yang mengeras menyerupai batu. Saat ini telah banyak orang-orang yang menggunakan beton di dalam pekerjaan struktur, apalagi dengan berbagai macam kemajuan teknologi yang ada. Namun satu hal yang pasti yaitu tak ada hal yang sempurna di dunia ini, beton juga dapat mengalami kerusakan. Kerusakan ini diakibatkan oleh berbagai macam hal seperti risak karena pengaruh fisik, mekanik dan kimia.Kerusakan yang terjadi pada salah salu dermaga di Pelabuhan Panjang adalah suatu contoh kerusakan struktur beton yang diakibatkan oleh pengaruh kimia atau lingkungan. Lebih spesifik lagi adalah kondisi lingkungan yang berhubungan oleh air laut sehingga timbul korosi pada struktur beton bertulang tersebut.Pemecahan dari masalah di atas adalah perbaikan struktur beton bertulang dengan menggunakan material Grout LN 322 M, salah satunya dengan metode prepack concrete. Sebelum masuk pada inti permasalahan, telebih dahulu dilakukan penelitian tentang bahan perbaikan itu sendiri. Kemudian dilanjutkan dengan membandngkan modul balok pada kondisi normal dengan balok yang mengalami perbaikan. Hal-hal yang diamati antara lain prilaku dan kapasitas modul balok tersebut. Diharapkan agar prilaku modul balok yang mengalami perbaikan minimal sama dengan balok pada kondisi normal.Hasil test menunjukkan bahwa balok yang mengalami perbaikan pada sisi atas dengan material Grout LN 322M dan menggunakan metode prepack concrete mempunyai kinerja yang baik. Hal ini bisa dilihat dari besarnya kapasitas balok perbaikan. Dengan demikian bahan perbaikan Grout LN 322M dengan metode perbaikan prepack concrete dapat digunakan pada pekerjaan perbaikan struktur Dermaga D, Pelabuhan Panjang, Lampung.

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Nowadays people have used reinforced concrete in many construction work. It came along with the development of technology. But still there is a weakness, damages could be happened to reinforced concrete which caused by many factors such as physical, mechanical and chemical factor.

The damage occurred on reinforced concrete structure on Pier D Panjang Harbour Lampung was an example of damage that caused by chemical factor. More specifically, it was caused by saline water that strucked the structure, corroted the renforcemcnt and damaged the concrete.

The reparation of the reinforced concrete structure using Grout LN 322M with perpaclc concrete method has become one of the alternatives that could be applied to the structure on Pier D, Paniang Harbour. Lampung. One thing that need to be done is a research about the repairing agent Grout LN 322M itself. Next continued with several simulations and series of tests against beam modules to compare the workability and capacity between normal beam module and repaired beam module.

The results had shown that the beam repaired at top side with Grout LN 322M using prepack concrete method has a good performance. It can be seen from the capacity of the repaired beam. So the prepack concrete method can be applied to repair the damage o Pier D, Panjang Harbour, lampung."

"It is widely use ofair-conditioning systems in Thailand due to its location. It is located in atropical zone with relatively high temperatures all year round, with highhumidity and high intensity of sunlight. In order to save electrical energy forair-conditioning systems, preventing heat transfer into the building isrequired. The objective of this study is to investigate the physical andthermal properties of concrete blocks. An attempt is made to increase heatresistance of concrete blocks. Foam beads (0-0.30% by weight) and kaolin (0-70% by weight) wereadded in concrete block mixture to increase discontinuous voids in concrete.Compressive strength and water absorption of concrete blocks were tested. Thetesting results indicated that compressive strength decreased when foam beadsand kaolin were added. Water absorption increased when foam beads were added.In contrast, the more kaolin added the less water absorption. The thermalconductivity coefficient of concrete blocks was also investigated. The resultsconfirmed that the higher the amount of foam beads or kaolin added, the higherthe thermal resistance of concrete blocks. Thermal time-lag behavior was alsoinvestigated. The results indicated that concrete block with kaolin took thelongest time in heating and took the shortest time in cooling. These propertiesare good for heat prevention in hot climate regions. These concrete blockswhich were developed and tested in this research conform to the Thai IndustrialStandard. Finally, it can be concluded that because of its thermal behavior,concrete block with kaolin is a suitable energy-saving concrete block for hotand humid climates."

"It is widely use of air-conditioning systems in Thailand due to its location. It is located in a tropical zone with relatively high temperatures all year round, with high humidity and high intensity of sunlight. In order to save electrical energy for air-conditioning systems, preventing heat transfer into the building is required. The objective of this study is to investigate the physical and thermal properties of concrete blocks. An attempt is made to increase heat resistance of concrete blocks. Foam beads (0−0.30% by weight) and kaolin (0−70% by weight) were added in concrete block mixture to increase discontinuous voids in concrete. Compressive strength and water absorption of concrete blocks were tested. The testing results indicated that compressive strength decreased when foam beads and kaolin were added. Water absorption increased when foam beads were added. In contrast, the more kaolin added the less water absorption. The thermal conductivity coefficient of concrete blocks was also investigated. The results confirmed that the higher the amount of foam beads or kaolin added, the higher the thermal resistance of concrete blocks. Thermal time-lag behavior was also investigated. The results indicated that concrete block with kaolin took the longest time in heating and took the shortest time in cooling. These properties are good for heat prevention in hot climate regions. These concrete blocks which were developed and tested in this research conform to the Thai Industrial Standard. Finally, it can be concluded that because of its thermal behavior, concrete block with kaolin is a suitable energy-saving concrete block for hot and humid climates."