Line and Color Composition in Lurik Cawas Weaving: Idea From Traditional Lurik Patterns

Javanese lurik is weaved fabric with striped motives, and it has very simple appearance. In the past, lurik only used two colors, namely: black and white. But, as it develops, some of lurik fabrics use more than two colors, and one of the colors usually still consists of black or white color. After lurik becomes one of the prosper trading commodities, the artisans attempt to make lurik more appealing and varying in term of appearance so that it will be favored by consumers. The objective of this research is to investigate how the artisans can develop lurik patterns to stay appealing. This paper used the qualitative research with the case study strategy and phenomenological approaches. The study aims at understanding the methods employed by artisans in Cawas Klaten in developing lurik patterns. The result of the study show that (1) lurik pattern has been developed by using various alternatives of line composition and color coherence; (2) the idea of development comes from traditional lurik patterns which already existed long time ago; and (3) line and color composition used a minimum of three colors so that it looks like a rainbow, and this kind of lurik pattern becomes the characteristic of modern weaved fabric from Cawas

Pengendapan Unsur Tanah Jarang Hasil Digesti Monasit Bangka Menggunakan Asam Sulfat

Unsur tanah jarang merupakan unsur yang banyak digunakan pada berbagai macam produk. Unsur tanah jarang yang berada di alam tidak ditemukan dalam keadaan bebas melainkan dalam bentuk senyawa kompleks sehingga diperlukan pengolahan secara kimia untuk memisahkan unsur tanah jarang dari senyawa kompleksnya. Monasit sebagai hasil samping proses pencucian timah Bangka mengandung beberapa unsur utama antara lain 0,298 % uranium (U), 4,171 % thorium (Th), 23,712 % fosfat (P2O5) dan 58,97 % oksida unsur tanah jarang (RE(OH)3). Monasit yang diolah secara kimiawi akan menghasilkan garam uranium, thorium, unsur tanah jarang dan fosfat. Unsur-unsur tersebut dapat dipisahkan secara individu melalui proses pengendapan secara bertahap. Proses pemisahan yang digunakan pada penelitian ini adalah metode pengendapan menggunakan asam sulfat sebagai reagen dan filtrat hasil digesti monasit Bangka sebagai umpan pengendapan. Proses digesti menghasilkan uranium, thorium, unsur tanah jarang dan fosfat yang terlarut dari senyawa kompleksnya. Unsur tanah jarang yang telah terlarut dapat dipisahkan dari unsur lainnya dengan metode pengendapan menggunakan asam sulfat. Penelitian ini bertujuan untuk mengetahui kondisi optimal pengendapan unsur tanah jarang. Hasil penelitian menunjukan bahwa jumlah H2SO4 yang ditambahkan sebanyak 3,5 kali volume umpan dan waktu pengendapan 20 menit, diperoleh persen rekoveri pengendapan 61,21 % REE, 78,46 % U dan 93,56 % PO4. Rare earth elements are elements that widely used in many products. Rare earth elements nature are not found in a free state, but they are in the complex compounds, so that chemically processing is required to separate the Rare earth elements from their complex compounds. Monazite as by product of Bangka tin process contains several major elements, such as 0.298% uranium (U), 4.171% thorium (Th), 23.712% phosphat (P2O5) and 58.97% rare earth elements (REE) oxide. These elements can be individually separated through a process of precipitation stages. The separation process used in the study is the method of acid by using sulfat acid as reagen and filtrat digestion as feeds. The process of digestion dissolve the elements U, Th, RE and phosphate from the complex compound. Rare earth elements that are disolved can be separated from the complex compounds by using sulfat acid precipitation process. The objective of research is to set the optimal conditions for the Rare earth elements precipitation with sulfat acid. The result showed that the amount of sulphuric H2SO4 which added is 3.5 times volume of feed and precipitation time is 20 minutes, percentage of precipitation recovery is 61.21 % REE, 78.46 % U, and 93.56 % PO4

Waste Tire Application in Concrete Structures

The waste tire is produced more than 10 million tons every year in the world. This problem needs serious treatment to eliminate the waste tires. This work is aimed to recycle the waste tire in concrete as a reinforcement. The contribution of the waste tires in flexural strength capacity of concrete is investigated by using experimental work and numerical simulation. Since material is quite non-homogenous compared to the pure concrete, we use six concrete beam specimens with dimension 150 mm x 150 mm x 1000 mm to get better fitting results. One specimen is non reinforced concrete beam and five specimens are waste tires reinforced concrete beam. For each of the five specimen, the waste tire reinforcement is tensioned with 0%, 17%, 25%, 40% and 60% strain before casting the concrete. The flexural strength tests are conducted after 28 days concrete ages under three point loadings. After the test, we observe that the waste tire reinforcement together with pre-stress contribute significantly on the flexural strength of the concrete beam as predicted. Finally, to support the test, finite element analysis is performed as well in this work and compared with the experimental results

Pengendapan Uranium Dan Thorium Hasil Pelarutan Slag II

Proses peleburan timah menghasilkan limbah berupa slag II dalam jumlah besar. Slag II sebagai terak pada proses peleburan timah masih mengandung beberapa unsur utama antara lain 0,0619% uranium, 0,530% thorium, 0,179% P2O5, dan 6,194% logam tanah jarang (LTJ) oksida total. Berdasarkan fakta tersebut, maka sangat menarik untuk meneliti pengolahan slag II, terutama untuk memisahkan uranium dan thorium yang terkandung di dalamnya. Uranium dan thorium dilarutkan dengan pelarut asam (H2SO4). Recovery pelarutan slag II dari hasil peleburan timah pada kondisi optimum adalah 98,52% uranium, 83,16% thorium, 97,22% fosfat, dan 69,62% LTJ. Uranium, thorium, LTJ, dan fosfat yang telah terlarut diendapkan agar masing-masing unsur terpisah. Faktor yang mempengaruhi kesempurnaan reaksi pada pengendapan antara lain reagen yang digunakan, pH reaksi, suhu, dan waktu. NH4OH digunakan sebagai reagen pengendapan dengan kondisi optimum proses pada pH 4. Suhu dan waktu reaksi tidak mempengaruhi proses. Recovery pengendapan yang dihasilkan adalah 93,84% uranium dan 84,33% thorium. Tin smelting process produces waste in the form of large amount of slag II. Slag II still consist of major elements such as 0.0619% uranium, 0.530% thorium, 0.179% P2O5 and 6.194% RE total oxide. Based on that fact, the processing of slag II is interesting to be researched, particularly in separating uranium and thorium which contained in slag II. Uranium and thorium dissolved using acid reagent (H2SO4). Percentage recovery of uranium, thorium, phosphate and RE oxides by dissolution method are 98.52%, 83.16%, 97.22%, and 69.62% respectively. Dissolved uranium, thorium, phosphat, and RE were each precipitated. The factors which considerable affect the precipitation process are reagent, pH, temperature, and time. NH4OH is used as precipitation reagent, optimum condition are pH 4. Temperature and time reaction did not influence this reaction. Percentage recovery of this precipitation process at optimum condition are 93.84% uranium and 84.33% thorium

The Renewability Indicator and Cumulative Degree of Perfection for Gamboeng Tea; Part.2, Exergy Calculation of Tea Factory

Renewability Indicator (RI) and Cumulative Degree of Perfection (CDP) were used to observe sustainability of Gamboeng Tea. The assessment then compared with black tea process in Black Sea Region in Turkey from the previous study. Calculation of exergy for Gamboeng fresh tea leaf had already described in Part.1. Since the main process for both production was drying, then tropical humid climate in Gamboeng is the main challenge to increase efficiency, and thus, renewability. This second part described the significant improvement of renewability had applied in Gamboeng by using wood pellet in rotary pannier. Further recommended improvement were by installing better humidity detector and connected to the process control so the process can adapt the ambient change which the relative humidity can be varied from 65% and up to 92%