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"Molibdenum disulfida merupakan aditif gemuk yang terkenal karena memiliki sifat ketahanan aus yang sangat baik. Ukuran partikel memengaruhi kinerja aditif, dimana semakin kecil ukuran partikel akan memberikan sifat ketahanan aus yang semakin baik. Namun diperlukan biaya yang semakin besar untuk memperoleh partikel berukuran kecil. Oleh karena itu, dibutuhkan penelitian terkait kombinasi ukuran partikel aditif molibdenum disulfida terhadap efektivitas kerja pelumasan gemuk untuk memaksimalkan efisiensi biaya yang diperlukan. Pembuatan gemuk dilakukan melalui reaksi saponifikasi minyak sawit sebagai bahan dasar dengan asam 12-hidroksi stearat, kalsium hidroksida, dan asam asetat sebagai pengental. Hasil bio-gemuk kalsium kompleks NLGI 2 selanjutnya dicampur dengan bubuk aditif molibdenum disulfida 1% b/b. Ukuran partikel aditif divariasikan menjadi 5 μm (Mb), 2 μm (Mk), dan 100 nm (N). Selain itu, dilakukan variasi kombinasi dua ukuran meliputi Mb+Mk, Mb+N, Mk+N, serta kombinasi tiga ukuran dengan komposisi berbeda. Partikel dikarakterisasi ukurannya menggunakan TEM dan PSA. Sedangkan gemuk dikaraktersasi menggunakan uji penetrasi, dropping point, dan four-ball. Hasil penelitian menunjukkan bahwa penambahan aditif molibdenum disulfida dapat mencegah keausan. Selanjutnya, kombinasi tiga ukuran terbukti efektif dalam meningkatkan performa anti-wear, diikuti dengan kombinasi dua dan satu ukuran, dimana hasil paling optimum yaitu dengan komposisi 1:1:1. Namun, penambahan aditif tidak memengaruhi tingkat penetrasi dan dropping point.

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Molybdenum disulfide is a grease additive known for its excellent anti-wear properties. Its performance is affected by particle size, where the smaller the particle will provide better anti-wear performance. In consequence, higher costs are needed. Therefore, research is needed on the particle size combination of molybdenum disulfide particles on tribological performance to achieve cost efficient grease. The grease is made through the saponification reaction of palm oil as base material with 12-hydroxystearic acid, calcium hydroxide, and acetic acid as thickener. The resulting NLGI 2 calcium complex bio-grease was then mixed with 1% w/w molybdenum disulfide powder. The additive particle size was varied into 5 μm (Mb), 2 μm (Mk), and 100 nm (N). Various combinations of two sizes were also carried out, while three sizes were varied by its compositions. Particles were characterized using TEM and PSA, meanwhile bio-grease using penetration, drop point, and four ball tests. The results showed that the addition of molybdenum disulfide could prevent wear. Furthermore, combination of three sizes was proven to be effective in increasing anti-wear performance, followed by combination of two and one size, with optimal results of 1:1:1. However, the addition of additives did not affect the penetration rate and drop point."

"[ABSTRAKTesis ini membahas pengaruh penambahan aditif pemodifikasi gesekan serbuk MoS2 ukuran 1 5 m dengan jumlah mulai 0 05 0 1 0 5 1 dan 2 berat dan ukuran 90 nm sebesar 0 05 0 1 0 5 pada minyak lumas dasar mineral HVI 60 terhadap karakteristik gesekan dan perlindungan keausannya Aditif ukuran 90 nm dan minyak lumas dasar dicampur dan diaduk menggunakan magnetik stirrer selama enam puluh menit pada suhu 50oC setelah itu dimasukkan ke dalam ultrasonic homogenizer selama satu jam sedangkan aditif ukuran 1 5 m pada suhu 75oC tanpa menggunakan ultrasonic homogenizer Campuran yang dihasilkan diuji karakteristik gesekan dan perlindungan keausannya menggunakan mesin uji four ball dan mesin uji SRV Analisis dilakukan pada material bola uji menggunakan optical emission spectroscopy OES goresan permukaan bola uji menggunakan scanning electron microscope SEM dan minyak lumas sisa pengujian dengan alat uji rotating disk electrode RDE Hasil penelitian menunjukkan bahwa penambahan aditif meningkatkan perlindungan keausan dengan dosis optimal sebesar 0 1 berat dengan rincian ukuran 1 5 m perbaikannya sebesar 23 dan ukuran 90 nm sebesar 11 Pengamatan permukaan goresan menunjukkan mekanisme keausan terjadi secara adesif dan abrasif Data yang diperoleh dari penelitian ini bisa digunakan sebagai dasar dalam pembuatan minyak lumas untuk aplikasi tertentu dengan mutu yang lebih baik

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ABSTRACTThis thesis discusses the influence of MoS2 friction modifier FM addition in the form of powder with two different mesh sizes i e 90 nm and 1 5 um on the friction and wear characteristic of HVI 60 base oil The variation of MoS2 were 0 05 0 1 0 5 weight whereas MoS2 1 5 um were 0 05 0 1 0 5 1 and 2 weight MoS2 additive 90 nm was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 50oC and homogenized in ultrasonic homogenizer for 1 hour For the MoS2 1 5 um the additive was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 75oC without using ultrasonic homogenizer Friction and wear characteristic of these mixtures were tested using four ball and SRV test rig Ball specimen surfaces were analyzed by using optical emission spectroscopy OES the wear scars were analyzed by using scanning electron microscope SEM while used mixtures from the test were analyzed by using rotating disk electrode RDE The results of the tests showed that the addition of 0 1 weight MoS2 additive both in 90 nm and 1 5 um resulted in an optimum increase in friction and wear characteristic of 23 and 11 respectively Observation on the wear scar showed that adhesive and abrasive wear mechanism were involved in the wear process The results of this research could be applied in production of lubricating oils for certain applications to improve their quality ;This thesis discusses the influence of MoS2 friction modifier FM addition in the form of powder with two different mesh sizes i e 90 nm and 1 5 um on the friction and wear characteristic of HVI 60 base oil The variation of MoS2 were 0 05 0 1 0 5 weight whereas MoS2 1 5 um were 0 05 0 1 0 5 1 and 2 weight MoS2 additive 90 nm was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 50oC and homogenized in ultrasonic homogenizer for 1 hour For the MoS2 1 5 um the additive was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 75oC without using ultrasonic homogenizer Friction and wear characteristic of these mixtures were tested using four ball and SRV test rig Ball specimen surfaces were analyzed by using optical emission spectroscopy OES the wear scars were analyzed by using scanning electron microscope SEM while used mixtures from the test were analyzed by using rotating disk electrode RDE The results of the tests showed that the addition of 0 1 weight MoS2 additive both in 90 nm and 1 5 um resulted in an optimum increase in friction and wear characteristic of 23 and 11 respectively Observation on the wear scar showed that adhesive and abrasive wear mechanism were involved in the wear process The results of this research could be applied in production of lubricating oils for certain applications to improve their quality ;This thesis discusses the influence of MoS2 friction modifier FM addition in the form of powder with two different mesh sizes i e 90 nm and 1 5 um on the friction and wear characteristic of HVI 60 base oil The variation of MoS2 were 0 05 0 1 0 5 weight whereas MoS2 1 5 um were 0 05 0 1 0 5 1 and 2 weight MoS2 additive 90 nm was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 50oC and homogenized in ultrasonic homogenizer for 1 hour For the MoS2 1 5 um the additive was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 75oC without using ultrasonic homogenizer Friction and wear characteristic of these mixtures were tested using four ball and SRV test rig Ball specimen surfaces were analyzed by using optical emission spectroscopy OES the wear scars were analyzed by using scanning electron microscope SEM while used mixtures from the test were analyzed by using rotating disk electrode RDE The results of the tests showed that the addition of 0 1 weight MoS2 additive both in 90 nm and 1 5 um resulted in an optimum increase in friction and wear characteristic of 23 and 11 respectively Observation on the wear scar showed that adhesive and abrasive wear mechanism were involved in the wear process The results of this research could be applied in production of lubricating oils for certain applications to improve their quality ;This thesis discusses the influence of MoS2 friction modifier FM addition in the form of powder with two different mesh sizes i e 90 nm and 1 5 um on the friction and wear characteristic of HVI 60 base oil The variation of MoS2 were 0 05 0 1 0 5 weight whereas MoS2 1 5 um were 0 05 0 1 0 5 1 and 2 weight MoS2 additive 90 nm was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 50oC and homogenized in ultrasonic homogenizer for 1 hour For the MoS2 1 5 um the additive was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 75oC without using ultrasonic homogenizer Friction and wear characteristic of these mixtures were tested using four ball and SRV test rig Ball specimen surfaces were analyzed by using optical emission spectroscopy OES the wear scars were analyzed by using scanning electron microscope SEM while used mixtures from the test were analyzed by using rotating disk electrode RDE The results of the tests showed that the addition of 0 1 weight MoS2 additive both in 90 nm and 1 5 um resulted in an optimum increase in friction and wear characteristic of 23 and 11 respectively Observation on the wear scar showed that adhesive and abrasive wear mechanism were involved in the wear process The results of this research could be applied in production of lubricating oils for certain applications to improve their quality ;This thesis discusses the influence of MoS2 friction modifier FM addition in the form of powder with two different mesh sizes i e 90 nm and 1 5 um on the friction and wear characteristic of HVI 60 base oil The variation of MoS2 were 0 05 0 1 0 5 weight whereas MoS2 1 5 um were 0 05 0 1 0 5 1 and 2 weight MoS2 additive 90 nm was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 50oC and homogenized in ultrasonic homogenizer for 1 hour For the MoS2 1 5 um the additive was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 75oC without using ultrasonic homogenizer Friction and wear characteristic of these mixtures were tested using four ball and SRV test rig Ball specimen surfaces were analyzed by using optical emission spectroscopy OES the wear scars were analyzed by using scanning electron microscope SEM while used mixtures from the test were analyzed by using rotating disk electrode RDE The results of the tests showed that the addition of 0 1 weight MoS2 additive both in 90 nm and 1 5 um resulted in an optimum increase in friction and wear characteristic of 23 and 11 respectively Observation on the wear scar showed that adhesive and abrasive wear mechanism were involved in the wear process The results of this research could be applied in production of lubricating oils for certain applications to improve their quality , This thesis discusses the influence of MoS2 friction modifier FM addition in the form of powder with two different mesh sizes i e 90 nm and 1 5 um on the friction and wear characteristic of HVI 60 base oil The variation of MoS2 were 0 05 0 1 0 5 weight whereas MoS2 1 5 um were 0 05 0 1 0 5 1 and 2 weight MoS2 additive 90 nm was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 50oC and homogenized in ultrasonic homogenizer for 1 hour For the MoS2 1 5 um the additive was mixed with base oil and stirred with magnetic stirrer for 60 minutes at 75oC without using ultrasonic homogenizer Friction and wear characteristic of these mixtures were tested using four ball and SRV test rig Ball specimen surfaces were analyzed by using optical emission spectroscopy OES the wear scars were analyzed by using scanning electron microscope SEM while used mixtures from the test were analyzed by using rotating disk electrode RDE The results of the tests showed that the addition of 0 1 weight MoS2 additive both in 90 nm and 1 5 um resulted in an optimum increase in friction and wear characteristic of 23 and 11 respectively Observation on the wear scar showed that adhesive and abrasive wear mechanism were involved in the wear process The results of this research could be applied in production of lubricating oils for certain applications to improve their quality ]"

"Kalsium karbonat merupakan aditif padat yang dapat meningkatkan performa anti-wear pada pelumas gemuk. Kinerja aditif dalam mengurangi jumlah keausan dipengaruhi oleh ukuran partikelnya, dimana ukuran partikel yang semakin kecil akan memberikan sifat ketahanan aus yang semakin baik. Namun, partikel yang semakin kecil akan memiliki harga yang semakin mahal. Penelitian ini bertujuan untuk meningkatkan performa gemuk dalam mengurangi jumlah keausan dan memaksimalkan efisiensi biaya dengan mengkombinasikan ukuran partikel aditif kalsium karbonat, yaitu ukuran mikro diatas asperities (Mb), ukuran mikro dibawah asperities (Mk) dan ukuran nano (N). Tiga ukuran tersebut dikombinasikan dengan komposisi berbeda. Pembuatan gemuk dilakukan melalui reaksi saponifikasi minyak sawit sebagai bahan dasar dengan asam 12-hidroksistearat, kalsium hidroksida, dan asam asetat sebagai pengental dan pengompleks. Gemuk bio kalsium kompleks dengan tingkat kekerasan gemuk multiguna (NLGI 2) yang dihasilkan selanjutnya dicampur dengan bubuk aditif kalsium karbonat sebanyak 1% dari basis gemuk, Partikel dikarakterisasi ukurannya menggunakan SEM. Gemuk yang dihasilkan dilakukan pengujian untuk mengetahui jumlah keausan menggunakan uji four ball dan untuk mengetahui pengaruh terhadap karakteristik gemuk yaitu konsistensi, kemuluran, dan dropping point. Hasil penelitian menunjukkan bahwa pada kombinasi mikropartikel dibawah ukuran asperities dan nanopartikel dengan rasio 50% : 50% menghasilkan performa terbaik dalam mengurangi keausan dan mengurangi biaya bahan baku pembuatan gemuk. Penambahan aditif tidak terlalu memengaruhi tingkat penetrasi, kemuluran dan dropping point.

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Calcium carbonate is a solid additive that is well-known for improving the anti-wear performance of bio greases. The performance of additives in reducing the amount of wear can be affected by its particle size, where the smaller particle size will provide better anti-wear performance. However, smaller particles are more expensive. Therefore, research is needed on the particle size combination of calcium carbonate particles on tribological performance to reduce the amount of wear and achieve cost efficient grease. The grease is made through the saponification reaction of palm oil as base oil with 12-hydroxystearic acid, calcium hydroxide, and acetic acid as thickeners and complexing agents. The resulting NLGI 2 calcium complex bio-grease (multi-purpose grease) was then mixed with 1% w/w calcium carbonate powder. The additive particle size was varied into three sizes: micro size above asperities (Mb), micro size below asperities (Mk), and nano size (N). The sizes were varied by its compositions. Particles were characterized using SEM, meanwhile bio-grease using penetration, drop point, and four ball tests. The results showed that the combination of microparticles below asperities (Mk) and nanoparticles (N) with a ratio of 50% : 50% produced the best performance in reducing wear and reducing the cost of raw material for making grease. The addition of additives does not significantly affect the level of penetration, fibril texture and dropping point."

"Partikel nano CaF2 ditambahkan ke dalam Gemuk kalsium oleat asetat kompleks untuk meningkatkan kualitas sifat pelumasannya, demi menjawab kebutuhan akan gemuk bio yang kian meningkat. Partikel nano CaF2 memiliki sifat pelumasan yang baik dan juga ramah lingkungan. Komposisi gemuk bio terdiri dari epoksida RBDPO sebagai base oil dan kalsium oleat serta kalsium asetat sebagai thickener dan pengompleks. Partikel nano CaF2 dipilih sebgai aditif padatan dan disintesis dengan menggunakan metode presipitasi. Terdapat dua tahap yang harus dilalui dalam pembuatan gemuk yaitu proses saponifikasi dan proses homgenisasi. Partikel nano CaF2 ditambahkan pada proses homogenisasi dan akan divariasikan jumlahnya antara 0.3-4.7% dari komposisi keseluruhan gemuk. Kualitas sifat pelumasan dari gemuk beraditf partikel nano CaF2 maupun tanpa aditif kemudian diuji dengan uji four ball dan dropping point. Hasil penelitian menunjukkan titik optimum penambahan partikel nano CaF2 adalah 0.3% dimana dapat menurunkan tingkat keausan dari jumlah keausan 1.8 mg menjadi 0.5 mg pada uji four ball dengan beban 62 kg selama 1 jam.

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CaF2 nanoparticles is added into calcium oleat acetate complex bio grease to increase the tribology properties, for answering the need of bio grease that is also increase troughout the years. Nanoparticles CaF2 have excellent lubricating properties and also don’t cause any harmful threat to the environment. Bio grease consists of RBDPO epoxide as base oil and Ca-Oleat: Ca-acetate as thickener and complexing agent. CaF2 nanoparticle is chosen as solid additive and synthesized by precipitation method. There are two stages in synthesizing bio grease which are saponification process and homogenization process. CaF2 nanoparticle is added in homogenization process and in different concentration (0.3-4.7%). The tribology properties of every bio grease are test by four balls and dropping point test. The result showed that with 1% addition of CaF2 can reduce amount of wear from 1.8 to 0.5 mg on four ball test with load 62 kg for an hour."

"ABSTRAKPembuatan gemuk bio kalsium kompleks dengan nilai NLGI (National Lubricating Grease Institute) #2 yaitu yang memiliki konsistensi semi-solid akan ditambahkan aditif talc untuk meningkatkan sifat antiwearnya serta mengurangi friksi. Gemuk yang dihasilkan berbahan dasar minyak kelapa sawit dan sabun kalsium kompleks sebagai thickening agent-nya. Sintesis gemuk tersebut dilakukan dengan cara melakukan proses pengadukan, pemanasan, dan reaksi saponifikasi pada suhu maksimum 165oC antara sabun kalsium kompleks secara in situ dalam minyak RBDPO (Refine Bleach Deodorized Palm Oil) yang terepoksidasi pada suhu 65oC. Selanjutnya dilakukan pendinginan dan homogenisasi pada suhu 70oC, serta penambahan aditif talc yang divariasikan komposisinya: 0%, 2,5%, 5%, 7,5%, dan 10% dari berat gemuk. Pengujian karakteristik dari gemuk bio yang dihasilkan meliputi uji konsistensi, uji dropping point dan four ball test dengan kecepatan putaran 1000 rpm. Adapun variable yang terdapat pada penelitian ini yaitu waktu dan suhu selama proses serta ukuran partikel talc sebagai variabel control; komposisi aditif talc sebagai variable bebas; komposisi base oil, thickener agent, dan aditif antioksidan BHT (Butylated Hydroxy Toluene) serta hasil uji karakteristik sebagai variable terikat. Gemuk terbaik yang dihasilkan memiliki sifat antiwear terbaik pada penambahan 2,5% talc dengan jumlah keausan terkecil 0,5 mg, dropping point pada suhu 265oC. Sementara pada penelitian sebelumnya gemuk terbaik yang dihasilkan memiliki jumlah keausan sebesar 0,7 mg pada penambahan 3,5% CaCO3.

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ABSTRACTMaking bio calcium complex grease with NLGI grades (National Lubricating Grease Institute) # 2 is that having a semi-solid consistency will be added talc additives to improve the antiwear properties and reduce friction. Grease generated based palm oil and calcium complex soap as a thickening agent of his. The grease synthesis is performed by the stirring process, heating, and a saponification reaction at a maximum temperature of 165oC between calcium complex soap in situ in the oil RBDPO (Refine Bleach Deodorized Palm Oil) is epoxidized at a temperature of 65oC. Furthermore, the cooling and homogenization at 70°C, and the addition of additives talc varied composition: 0%, 2.5%, 5%, 7.5%, and 10% by weight of fat. Testing characteristics of bio grease produced include test consistency, dropping point test and four-ball test with a rotation speed of 1000 rpm. The variables contained in this research that the time and temperature during the process as well as a variable talc particle size control; talc additive composition as independent variables; the composition of base oil, thickener agent, and antioxidant additives BHT (Butylated Hydroxy Toluene) as well as the characteristics of the test results as the dependent variable. Best bio grease produced has the best antiwear properties on the addition of 2.5% Talc with the smallest amount of wear of 0.5 mg, dropping point at a temperature of 265oC. While previous research has produced the best grease has the amount of wear 0.7 mg on the addition 3.5% CaCO3."

"ZnO nanorods adalah salah satu material semikonduktor yang banyak digunakan dalam fotodetektor karena memiliki luas area aktif yang besar, serapan cahaya yang tinggi, dan mudah difabrikasi. Namun demikian, arus gelap yang tinggi menjadi masalah utamanya. Untuk itu, salah satu upaya yang dilakukan adalah dengan membuat heterostructure ZnO dengan material semikonduktor lain. Dalam penelitian ini dibuat fotodetektor zinc oxide (ZnO) dengan jua jenis MoS₂ yaitu MoS₂ few-layer dan MoS₂ many-layer yang akan dideposisi diatas ZnO dengan metode spin coat. Pengujian fotodetektor dilakukan dibawah penyinaran sinar UV (365 nm) dan cahaya tampak (505, 625 nm) pada tegangan 2V. Hasil penelitian menunjukkan adanya peningkatan kinerja dari segi sensitivitas, responsivitas, dan detektivitas setelah penmabahan MoS₂. Peningkatan kinerja ini diakibatkan oleh penurunan arus gelap yang mungkin disebabkan oleh pasivasi permukaan yang dapat menekan jumlah muatan bebas dari defect ZnO.

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ZnO nanorod is a semiconductor material that is widely used in photodetector device because it has large active area, high light absorption, and  easy to manufacture. However, the high dark currents were the main problem. For that, one of the efforts made is to make the ZnO heterostructure with other semiconductor materials. In this research, zinc oxide (ZnO) photodetector was made with two types of MoS₂, namely multiple-layer MoS2 and many-layer MoS2 which will be deposited on ZnO with the spin coat method. Photodetector testing was carried out under UV light (365 nm) and visible light (505, 625 nm) at a voltage of 2V. The results showed an increase in performance in terms of sensitivity, responsivity, and detectivity after the deposition of MoS₂. The increase in performance is due to decrease in dark currents which may be due to surface passivation which can reduce the amount of free charge from the ZnO defect."

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Partikel padat grafit telah diketahui digunakan sebagai aditif anti-wear untuk meningkatkan performa gemuk. Skala ukuran partikel padat, khususnya nanopartikel memiliki peran utama dalam mengurangi jumlah keausan secara signifikan. Namun, harga nanopartikel jauh lebih mahal dibandingkan mikropartikel. Penelitian ini bertujuan untuk meningkatkan performa gemuk bio kalsium kompleks dalam mengurangi jumlah keausan dengan mengkombinasikan nanopartikel dan mikropartikel dengan ukuran berturut-turut yaitu 41 nm hingga 71 nm dan 1 𝜇𝑚 hingga 3,9 𝜇𝑚. Komposisi nanopartikel : mikropartikel divariasikan dalam kombinasi dengan interval 10% dalam 1% dari total basis gemuk. Penelitian diawali dengan pembuatan gemuk menggunakan minyak RBDPO (Refined, Bleached, Deodorized Palm Oil) sebagai minyak dasar serta asam 12-Hidroksi stearat dan asam asetat sebagai pengental. Partikel grafit didispersikan pada saat homogenisasi gemuk. Hasil penelitian menunjukkan bahwa pada kombinasi perbandingan nanopartikel dan mikropartikel dengan rasio 40% : 60% menunjukkan adanya efek kinerja kombinasi antara nanopartikel dan mikropartikel dalam mengurangi jumlah keausan, dimana pada komposisi rasio 50% : 50% dan 60% : 40% menghasilkan performa terbaik dalam mengurangi keausan dibandingkan hanya menggunakan nanopartikel saja, dengan demikian ukuran kombinasi nano-mikro juga dapat mengurangi biaya bahan baku pembuatan gemuk dengan 100% nanopartikel. Selain itu, seiring dengan peningkatan komposisi nanopartikel dalam kombinasi maka konsistensi dan nilai dropping point gemuk.

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Solid particles of graphite have been known to be used as an anti-wear additive to improve grease performance in reducing wear. The size scale of solid particles, especially nanoparticles has a major role in reducing the amount of wear significantly. However, the price of nanoparticles is much more expensive than microparticles. This study aims to improve the performance of bio calcium complex grease in reducing wear by combining nanoparticles and microparticles with sizes 41 to 71nm and 1 to 3.9 . The composition of nanoparticles: microparticles were varied in combination with an interval of 10% within 1% of the total grease base. The synthesis of grease using RBDPO oil as a base oil and 12-Hydroxystearic acid and acetic acid as thickeners. The graphite particles are dispersed during the homogenization of the grease. The results showed that the combination of the ratio of nanoparticles and microparticles with a ratio of 40%: 60% showed a performance effect of the combination of nanoparticles and microparticles in reducing the amount of wear, where the composition ratios of 50%: 50% and 60%: 40% produced the best performance in reducing wear compared to using only nanoparticles, thus nano-micro combination can also reduce the cost of grease material by 100% nanoparticles. In addition, along with the increase in the composition of the nanoparticles in the combination, the consistency and dropping point value of the grease increases.

 

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"Molybdenum is an emerging pollutant worldwide. The objective of this study is to isolate molybdenum-reducing bacterium with the ability to grow on phenolic compounds (phenol and catechol). The screening process was carried out on a microplate. The bacterium reduced molybdenum in the form of sodium molybdate to molybdenum blue (Mo-blue). The bacterium required a narrow pH range for optimal reduction of molybdenum, i.e. between  pH 6.3 and 6.8, with temperature between 34 and 37 oC. Molybdate reduction to Mo-blue was best supported by glucose as the carbon source. However, both phenol and catechol could not support molybdate reduction. Other requirements for molybdate reduction included sodium molybdate concentrations between 15 and 30 mM, and phosphate concentration of 5.0 mM. The bacterium exhibited a Mo-blue absorption spectrum with a shoulder at 700 nm and a maximum peak near the infrared region at 865 nm. The Mo-reducing bacterium was partially identified as Enterobacter sp. strain Saw-2. The capability of this bacterium to grow on toxic phenolic compounds and to detoxify molybdenum made it a significant agent for bioremediation."

"ABSTRAKPada pembuatan gemuk bio ini digunakan Kalsium karbonat atau CaCO3 berukuran submikro-mikro sebagai aditif padat untuk meningkatkan sifat antiwear dari gemuk bio yang dihasilkan dengan NLGI #2. Penelitian ini diawali dengan pengepoksidasian minyak sawit pada suhu 65 ˚C; sintesis gemuk bio yang meliputi proses pengadukan, pemanasan, dan saponifikasi pada suhu maksimum 165 ˚C; homogenisasi pada suhu 70 ˚C; serta pengujian karakteristik dan performa gemuk bio yang meliputi uji konsistensi, uji dropping point, serta four ball test untuk menguji sifat antiwear gemuk bio dengan kecepatan putaran sebesar 1150 rpm. Adapun variabel yang terdapat pada penelitian ini yaitu waktu dan suhu selama proses sebagai variabel control; komposisi aditif CaCO3 sebagai variabel bebas; ukuran partikel CaCO3, komposisi base oil, thickener agent, dan BHT serta hasil uji karakteristik sebagai variabel terikat. Hasil yang didapat yaitu gemuk bio NLGI #2 dengan dropping point pada suhu 301 ˚- 317 ˚C. Untuk hasil pengujian antiwear terbaik didapat pada gemuk bio dengan penambahan 3,5% CaCO3 submikro-mikro dengan pengurangan massa ball bearing sebesar 0,7 mg, sementara pada gemuk bio dengan 0% CaCO3 pengurangan tersebut sebesar 250 mg.

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ABSTRACTIn the making of this bio grease, calcium carbonate or CaCO3 in submicro-micro size is used as a solid additive to increase its antiwear properties. To start the research, the epoxidation of palm oil in 65 ˚C is done first; and then synthesizing of bio grease which consists of mixing, heating, and saponification with maximum temperature at 165 ˚C; homogenization in 70 ˚C; and characterization tests that includes the concistency test, dropping point test, and four ball test. The variable contained in this research are time and temperature as control variable; composition of CaCO3 as independent variable; CaCO3 particle size, composition of base oil, thickener agent, BHT, and the result of characterization test as dependent variable. To start the research, the epoxidation of palm oil is done first, and then synthesizing of bio grease, and characterization testing that includes the elasticity test, concistency test, dropping point test, and four ball test in 1150 rpm. The results of this research are, the bio grease has NLGI #2 with 301 ˚- 317 ˚C in dropping point test. For the antiwear test, the best result is possessed by bio grease with 3.5% of CaCO3 addition with reduction of mass ball bearing as much as 0.7 mg, meanwhile in bio grease with 0% of CaCO3 gave 250 mg reduction of mass ball bearing."

"Pengembangan terhadap paduan zirkonium sebagai biomaterial yang diproduksi melalui proses metalurgi serbuk diteliti dengan diberikan perlakuan panas pada komposisi unsur paduan molibdenum (3%, 6%, dan 9% massa Molibdenum) serta dihubungkan terhadap densitas dan porositas, struktur mikro dan kekerasan menggunakan pengujian Rockwell C.Dari hasil pengujian didapatkan bahwa struktur mikro yang dominan terbentuk adalah fasa α-Zr dan Mo2Zr, dan dengan pemberian perlakuan panas struktur mikro yang terlihat menjadi lebih jelas batas butirnya. Dari hasil uji densitas dan porositas, poros yang terbentuk semakin bertambah seiring bertambahnya jumlah Molibdenum yang diberikan, perlakuan panas memberikan efek yang buruk karena akan menambah jumlah poros dari molibdenum yang menguap diatas suhu 600oC. Dari hasil kekerasan yang dicapai unsur molibdenum tidak memberikan efek yang terlalu signifikan walau kekerasan bertambah seiring dengan jumlah molibdenum yang bertambah, dengan perlakuan panas kekerasan turun dikarenakan porositas setelah diberi perlakuan panas bertambah.

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Development of zirconium alloy as biomaterial produced by powder metallurgy method is studied from effect of heat treatment with different compositions of molybdenum. ( 3%, 6% and 9% weight of Molybdenum), its density and porosity, microstucture and hardness using Rockwell C method. From the experimental, the dominan microstructure formed is α-Zr and Mo2Zr phase and by heat treatment it is clearer to see boundary and grain boundary. From density and porosity test, the formed porous increase as composition molybdenum increase, heat treatment give negative effect, mollybdenum will formed molybdenum oxided vollatile when heated above 6000C. From hardness test, molybdenum does not give significant effect to the hardness. The hardness increase as the composition of molybdenum increase, also hardness decrease due to the increase of porosity after heat-treatment."