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"ABSTRAKNatural fiber reinforced polymer composites are widely developed because of their relative low price and eco-friendly. One of natural fiber sourches is pandanus tectorius leaf. This study aimed to determine the effect of variations in fiber volume fraction on tensile strength, impact strength, bending strength and morphological on sea pandanus fibers- polypropylene composites.Tensile test spesimen refer to ASTMD 638, impact test spesimen refes to ASTMD 5942-96, bending test spesimen refer to ASTMD 790 -02. The increasing of the volume fraction increased the tensile strength and impact strength. The tensile test results showed the highest tensile strength results for composites with a volume fraction of 35% was 25.82 MPa. The impact test results showed that the highest impact strength was obtained in the 35 % volume fraction of 0.0062 Joule/mm2. The bending test results showed that the highest bending strength was obtained in the 20% volume fraction of 24.96 MPa. Based on SEM test results, there were voids, cracks, fibers pull out on the composite."

"Rem adalah komponen vital dalam kendaraan yang berfungsi mengurangi kecepatan dan menghentikan kendaraan. Brake shoe yang diperoleh oleh industri umum saat ini terbuat dari besi cor, yang memiliki densitas dan gesekan tinggi yang menyebabkan terjadinya percikan selama pengereman. Dalam penelitian ini dipelajari mengenai sifat mekanik dan mikrostruktur ADC12 dengan komposit SiC mikro untuk menggantikan besi cor dalam pembuatan sepatu rem untuk kereta. Komposit dibuat dengan metode pengecoran aduk dan ditambahkan kandungan Ti 0.04, 0.06, 0.15, 0.3 dan 0.5 wt. TiB bertindak sebagai penghalus butir yang meningkatkan sifat mekanik secara signifikan karena butir menjadi lebih halus dan seragam. Sepuluh persen berat Magnesium ditambahkan untuk meningkatkan kemampubasahan dari komposit tersebut. Beberapa pengujian yang dilakukan untuk mengkarakterisasi material komposit adalah: OES, XRD, OM, SEM, dan pengujian merusak seperti tarik, kekerasan, keausan, danimpak. Hasilnya, komposisi optimum ditemukan pada komposit ADC 12/SiC dengan menambahkan 0.15 wt TiB yang menghasilkan UTS sebesar 136 MPa, kekerasan sebesar 53 HRB, laju aus sebesar 0.99 mm3/s, dan harga impak sebesar 0.097 J/mm2.

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Brake is a vital component in a vehicle that works on reducing speed and stopping the vehicle. Brake shoe obtained by common industries is currently made of a cast iron, which has a high density and a high friction that caused sparks during braking. The mechanical properties and microstructure of the ADC12 with micro SiC composites to replace cast iron in the making of brake shoe for train have been studied in this work. The composites were made with stir casting method and were added Ti content of 0.04, 0.06, 0.15, 0.3 and 0.5 wt. TiB act as grain refiners that improve the mechanical properties significantly because the grain becomes finer and more uniform and 10 wt Magnesium was added to improve the wettability of the composites. Several test were conducted to characterize the material OES, XRD, OM, SEM, and destructive test such as tensile, hardness, wear, and impact. As the result, the optimum composition was found by adding 0.15 wt of TiB which results 136 MPa in Ultimate Tensile Strength UTS , 53 HRB in hardness, 0.99 mm3 s in wear rate, and 0.097 J mm2 on impact testing."

"Penelitian ini bertujuan untuk mengevaluasi pengaruh durasi penyinaran terhadap kekuatan tarik diametral resin komposit bulk-fill. Enam puluh spesimen Tetric N-Ceram Bulk-Fill ketebalan 3 mm dan diameter 6 mm; warna IVA dan IVW dibagi ke dalam 3 kelompok berdasarkan durasi penyinaran 10 detik, 15 detik, dan 20 detik untuk setiap warna. Spesimen dipolimerisasi dengan LED curing unit Bluephase Style, 1.280 mW/cm2 dan diuji kekuatan tarik diametralnya menggunakan uji statistik Universal Testing Machine. Data yang diperoleh dianalisis menggunakan One-Way ANOVA dan Post-Hoc Tukey HSD. Hasil menunjukkan adanya perbedaan bermakna.

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This study was conducted to evaluate the influence of different exposure time and bulk fill composite shade on its diametral tensile strength. Sixty disc shaped specimens of Tetric N Ceram Bulk Fill 3 mm of thickness x 6 mm of diameter shade IVA and IVW were divided into 3 subgroups for each shade according to exposure times 10 s, 15 s, and 20 s . All specimens were polymerized using LED curing unit Bluephase Style, 1.280 mW cm2 and tested using Universal Testing Machine to determine its diametral tensile strength. Data were statistically analyzed using One Way ANOVA dan Post Hoc Tukey test. The result showed a significant differences in all groups."

"Karakterisasi Komposit AC4B/Nano TiC Dengan Variasi Fraksi Volume Nano TiC Reinforce oleh Stir Casting Process telah diselidiki. Penulis digunakan paduan aluminium seri tiga, AC4B, yang mengandung silikon dan tembaga sebagai paduan utamanya. Selanjutnya, penambahan Nano TiC ke dalam komposit AC4B dapat meningkatkan daya tarik kekuatan, daktilitas, dan ketangguhan komposit AC4B dengan menyempurnakan struktur dendrit dari fase α-Al dan membentuk fase padat super jenuh, θ (Al2Cu). Dalam studi ini, Komposit AC4B / Nano TiC dibuat melalui stir casting dengan beberapa variabel parameter Nano TiC memperkuat komposisi 0,25%, 0,3%, 0,35%, 0,4%, dan 0,5% fraksi volume untuk menentukan nilai optimal dari sifat mekanik AC4B/komposit Nano TiC. Proses casting stir dipilih karena memiliki beberapa kelebihannya, seperti mudah digunakan, fleksibel, dan dapat digunakan untuk menghasilkan sejumlah besar produk. Diketahui bahwa komposit AC4B/Nano TiC memiliki nilai optimum sifat mekanik ketika komposisi Nano TiC adalah fraksi volume 0,3% dengan kekuatan tarik utama 132,31 MPa dan kekerasan 55,18 HRB.

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Characterization of AC4B/Nano TiC Composites with Variations in Reinforce Nano TiC Volume Fractions by the Stir Casting Process has been investigated. The author used three series aluminum alloy, AC4B, which contained silicon and copper as its main alloy. Furthermore, the addition of Nano TiC to the AC4B composite can increase the tensile strength, ductility, and toughness of the AC4B composite by perfecting the dendrite structure of the α-Al phase and forming a super saturated solid phase, θ (Al2Cu). In this study, AC4B/Nano TiC composites made by stir casting with several variable parameters Nano TiC strengthens the composition of 0.25%, 0.3%, 0.35%, 0.4%, and 0.5% volume fraction to determine the optimal value of the properties mechanical AC4B/Nano TiC composites. The casting casting process was chosen because it has several

its advantages, such as easy to use, flexible, and can be used to produce a large number of products. It is known that the AC4B/Nano TiC composite has optimum mechanical properties when the composition of Nano TiC is a volume fraction of 0.3% with a main tensile strength of 132.31 MPa and a hardness of 55.18 HRB.

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"The traditional fiber reinforced composite (FRC) contains bishpenol A glycidyl methacrylate (bis-GMA) in the resin matrix, which is thought to have some disadvantages. This research aimed at replacing bis-GMA with another monomer-urethane dimethacrylate (UED-MA), with the desired properties for dental use still retained. Four groups were prepared with light-curing (n = 30), one Control group with a bis-GMA-based resin matrix and three experimental groups with UEDMA-based matrices (Exper 1, Exper 2 and Exper 3 with a varying UEDMA weight percentage). Specimens were stored in dry conditions for 24 h or in deionized water for 1, 3, 6 or 12 months prior to the tests. Water sorption (n = 6), Vicker's hardness (n = 6) and flexural properties (n = 6) after each storage time were investigated.Scanning electron microscopy (SEM) images were taken at the fracture sites after 3-point bending. All the results were statistically analyzed (α = 0.05). The Exper 1 group exhibited the lowest weight increase after water storage among the experimental groups. As for dry conditions, 1- and 6-month storage, different resin matrix compositions made no significant difference to hardness, while for 3- and 12- month storage, "Control" possessed the highest hardness. The Control group's strength and modulus, Exper 1 and Exper 2's modulus were stable during water storage. Compared to other experimental groups, Exper 1 had the highest strength and modulus values with most of the storage times. SEM images showed relatively good adhesion between the fiber and the matrix. With all the tested properties considered, the Exper 1 group had superior performance among all the three experimental groups."

"Dewasa ini penggunaan material komposit serat karbon mulai banyak digunakan dalam berbagai sektor industri karena memiliki sifat-sifat yang mampu memenuhi tuntutan teknologi, seperti ringan, tahan fatik, dan tahan terhadap temperatur tinggi. Penelitian terhadap perfoma komposit serat karbon baik termal dan mekanik masih jarang dilakukan. Oleh karena itu dilakukanlah pengujian untuk mengetahui hal tersebut. Komposit serat karbon yang digunakan memiliki variasi densitas berbeda yaitu 200 dan 240 gr/m2Metode yang digunakan dalam penelitian ini berbasis pada kalorimeter kerucut. Pembakaran dilakukan pada nilai fluks kalor maksimum 23,61 kW/m2 dan minimum 14,15 kW/m2. Pada penelitian ini juga dilakukan pengujian tarik dan SEM untuk mengetahui sifat mekanik dari komposit serat karbon. Hasil dari penelitian ini menunjukkan semakin tinggi fluks kalor, maka laju produksi kalor dari pembakaran komposit serat karbon juga meningkat dimana laju produksi maksimum yang dicapai bernilai 160-170 kW/m2. Sementara itu dari pengujian mekanik didapatkan bahwa material komposit serat karbon memiliki sifat diantara ulet dan getas.

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In this present days, the use of carbon fiber composite material used widely in various industrial sectors. This happens because carbon fiber composite have good properties that can fulfill the demands of technology requirements, such as lightweight, fatigue resistant, and withstand to high temperatures. Studies on carbon fiber composites performance, especially regarding its thermal and mechanical performance, are still not observed widely. Carbon fiber composites used in this study has density of 200 and 240 gr/m2.

The method used in this study based on cone calorimeter. Combustion was performed onthe maximum heat flux of 23.61 kW/m2 and a minimum heat flux of 14.15 kW/m2. This study also used the tensile test and SEM analysis to determine the mechanical properties of carbon fiber composites.

The results of this study showed that at the higher heat flux, the heat release rate (HRR) carbon fiber composites was increased withthe maximum valueof 160-170 kW/m2. Meanwhile, analysis of mechanical properties showed that the carbon fiber composite material has a characteristic between ductile and brittle."

" ABSTRAK Penambahan partikel nano SiC ke dalam matriks Al 6061 telah terbukti memberikan efek penguatan terhadap sifat mekanis dari komposit bermatriks logam dengan mempertahankan keuletannya. Untuk meningkatkan sifat mekanisnya, komposit hasil pengecoran diberikan perlakuan panas pada beberapa temperatur aging. Sebagai wetting agent, 10 wt Magnesium ditambahkan ke dalam komposit untuk mendapat ikatan antarmuka yang kuat. Pada penelitian ini, Al 6061 diperkuat dengan 0,15 vf nano SiC dibuat, lalu diberikan perlakuan panas pada beberapa temperatur aging 140 oC, 160 oC, 180 oC, 200 oC, dan 220 oC . Hasil dari penelitian ini menunjukkan bahwa temperatur aging optimum adalah 180 oC yang dilakukan selama 8 jam, dengan nilai kekuatan tarik maksimum UTS mendapai 240 MPa, nilai kekerasan mencapai 72 HRB. Efek penguatan yang terjadi pada komposit dipengaruhi oleh adanya fasa Mg 2 Si, endapan Mg 2 Si dan Mg 5 Al 8, distribusi partikel nano SiC yang baik, dan juga ikatan antarmuka matriks dengan penguat yang baik.

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ABSTRACT The addition of nano SiC particles to Al6061 matrix has enhancing the mechanical properties of metal matrix compoite while the ductility properties still maintaned. To improve the mechanical properties, the as cast composites are heat treated to various aging temperature. As the wetting agent, 10 Vf Magnesium were added into the composite to achieve strong interface bonding. In the present work, Al6061 reinforced with 0,15 Vf of nano SiC were prepared, then heat treated to various aging temperature 140 oC, 160 oC, 180 oC, 200 oC, and 220 oC . Result of this studies shows that the optimum aging temperature was 180 oC that was conducted for 8 hours, with UTS Ultimate Tensile Strength reached 242,52 MPa, and hardness value up to 71,7 HRB. The enhancement of mechanical properties of composite were influenced by the presence of Mg 2 Si phase, Mg 2 Si and Mg 5 Al 8 precipitates, good distribution of nano SiC particles, also good interfacial bonding between matrix and reinforce. "