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"Plastic limit is an important property of fine-grained soils. The standard thread-rolling method for determining the plastic limit has long been criticized for requiring considerable judgments from the operator. This study was conducted to seek for a new method on the determination of the plastic limit in a way to overcome the inconsistence result produce by using the standard thread-rolling method. Four different methods were tested. The first method was the modified fall cone method, a method commonly used to obtain a liquid limit. The second method was the rolling device method which is previously proposed by Bobrowski and Griekspoor (1992). The third method was proposed by Wood and Wroth (1978) using a heavier cone. The fourth method was the one proposed by Tao-Wei Feng (2004) which made use of a small soil container. Eight soil samples representing plasticity index (PI) ranging from 15 to 42% were tested. The results indicated that the correlation factor between the standard methods and the suggested methods were in the range 0.72 and 0.99. Regarding to the regression analysis result, the first method is more comparable to the standard thread method"

"The increase in the efficiency of fuel utilization is an important aspect in transportation. This can be obtained by reduction of vehicle weight. The application of light weight materials is being intensively assessed and studied. Reinforced plastics/ composites is one of the materials that can be used for this aim . The investigation was directed to Spectra-900 fiber/ UP and E-glass fiber/ UP composites. The investigation consists of composites compound analysis and testing of its mechanical properties. The composites was made by hand lay-up molding process and the fiber in the matrix was arranged in an unidirectional. Results showed that Spectra-900 fiber, as is E-glass, has the function as reinforce material/ fiber. Therefore, Spectra-900 fiber has the opportunity to be utilized in the construction of transportation vehicle.

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Dalam bidang transportasi, peningkatan efisiensi penggunaan bahan bakar merupakan aspek yang sangat panting. Hal ini dapat dicapai dengan cara mengurangi berat kendaraan yang bersangkutan. Penggunaan material yang lebih ringan masih terus dikaji ditelaah. Salah satu bahan/ material yang mungkin digunakan untuk tujuan tersebut adalah plastik yang diperkuat komposit. Penelitian diarahkan pada komposit serat Spectra-900/ UP dan serat gelas-E/ UP. Penelitian ini terdiri dari analisa terhadap komponen penyusun komposit dan pengujian sifat mekanik dari komposit. Komposit yang diuji dibuat dengan proses pencetakan secara hand lay-up dan serat disusun satu arah dalam matriks. Hasil pengujian memperlihatkan bahwa serat Spectra-900 berfungsi sebagai bahan/ serat penguat yang sama dengan serat gelas-E. Dengan demikian serat ini mempunyai peluang untuk digunakan dalam pembuatan konstruksi alat transportasi."

"Sebagai kemasan, Jelly Cup pada prinsipnya hanya sekali pakai saja (disposable) sehingga menjadi tuntutan utama agar kemasan seringan mungkin untuk menghemat biaya material dan juga isu lingkungan yang menganjurkan sesedikit mungkin penggunaan plastik. Optimasi awal produk Jelly Cup 100 ml dilakukan dengan simulasi CAE menggunakan perangkat lunak mpa (moldflow plastic advisor) dan dilanjutkan dengan mpi (moldflow plastic insight) dengan parameter utama ketebalan dinding yang berhubungan dengan berat produk Tujuannya adalah mendapatkan tebal dinding setipis mungkin untuk diproses pada cetakan injeksi. Analisis hasil simulasi komputer menunjukkan ketebalan yang optimum untuk produk Jelly Cup 100 ml ini adalah 0.5 mm. Optimasi berikutnya adalah desain cetakan yang dilakukan meliputi 4 bagian utama pada cetakan yaitu: konstruksi pada rongga cetak, sistem saluran masuk (feeding system), sistem pendingin (cooling system), sistem pengeluaran produk (ejection system). Percobaan eksperimental dengan metoda trial and error dilakukan dalam tiga macam ketebalan yaitu: 0.42, 0.46, dan 0.50 mm. Hasilnya menunjukkan pada ketebalan 0.46 dan 0.50 memungkinkan untuk mencetak produk yang baik, perbedaannya ada pada tekanan injeksi dan waktu siklus. Setelah dilakukan analisa dan diskusi, maka didapatkan bahwa ketebalan 0.50 mm memang merupakan ketebalan yang ideal dan mendekati hasil simulasi (waktu siklus 4.1-4.2 detik dan berat produk 4.1 gram), tetapi secara ekonomis, berdasarkan asumsi saat ini, ketebalan 0.46 mm lebih menguntungkan untuk diproduksi (waktu siklus 4.5-4.6 detik dan berat produk 3.8 gram). Produk Jelly Cup teroptimasi menjadi Thin Wall Product dengan flow length/wall thickness ratio (111) terbesar 128.111. Perubahan ketebalan tidak berpengaruh secara signifikan terhadap kekuatan impak produk setelah dilakukan percobaan drop test.

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As a packaging, Jelly Cup in principle only for one time use (disposable), so the main factor is the cup has to be as light as possible to save material cost and considering of environment issues suggesting a few possible plastic uses. CAE simulation with mpa (moldflow plastic adviser) software and continued by mpi (moldflow-plastic insight) conducted as early optimization stage and the main parameter is wall thickness which deal with product weight. The target is get wall thickness as thin as possible to be processed at injection molding. Analyze result of computer simulation show the optimum wall thickness for the product of this Jelly Cup 100 ml is 0.5 mm. Next stage is optimization of molding design that consist of 4 main system i.e. cavity, feeding system, cooling system, and ejection system. Experimental process done to validate the optimization. Method that used in this experiment is trial and error of injection molding of Jelly Cup 100 ml with 3 kind of wall thickness i.e. 0.42, 0.46, and 0.50 mm. These trials used practical process parameters as close as the real production condition. The result shows Jelly Cup with wall thickness 0.46 and 0.50 mm have possibility to produce. The differences between them are the value of injection pressure and cycle time. After analysis and discussion, wall thickness 0.50 mm is the ideal wall thickness and very close to simulation result (cycle time is 4.1-4.2 s and product weight is 4.1 g), but according to economic calculation, with recent assuming, show the advantage to produce 0.46 mm product slightly higher than another (cycle time is 4.54.6 s and product weight is 3.8 g). Jelly Cup product optimized to thin wall product with flow length 1 wall thickness ratio (1J) 128.111. The drop test result shows the changes of thickness not significant for drop impact resistance."

"Buku yang berjudul "Dictionary of plastics" ini ditulis oleh J. A. Wordingham dan P. Reboul. Buku ini merupakan sebuah kamus mengenai plastik."