Judul: Finansial Feasibility Study for Poly Aluminum Chloride (PAC) Plant
Abstrak: Indonesian government issued a mining law no.4 of 2009 on the prohibition of the ore export. PT AntamTbk as a mining company is affected by the implementation of thisregulation. PT AntamTbk has abundant and high quality resources of ore especially nickel and bauxite ore can’t be maximally utilized due to the needs of the processing plant of PT AntamTbk, which at present can only process limited capacity and other processing plants in Indonesia are also very limited. Ore resources have to beprocessed or refined to get more added value and benefit. Strategy that PT AntamTbk uses to overcome this is to build processing plants for its mineral reserves to be processed into raw materials, auxiliary materials, or even a finished products. One of strategic initiatives is to build PAC Plant which can utilize alumina tryhidrat from bauxite ore made by Antam’s subsidiary to have more added value. The purpose of this research to study the feasibility of a PAC plant project. In carrying out this feasibility study four aspects were discussed: market aspects, technical aspects, aspects of location, organization aspect, and analyze the financial feasibility of PAC project investment. In the market aspect uses descriptive qualitative analysis methods, assessing demand and supply in Indonesia, PAC products, price, promotion, end users PAC in Indonesia, and marketing strategies for PAC in Indonesia. Study on organization aspects consist of organization's strategy, organization structure, manpower and rewards. Study on technical aspect consists of study on production process, production equipment, factory layout, and raw materials. Study on location aspect is to find best location for its project. Among three alternatives location, Krakatau Industrial Estate Cilegon (KIEC) is the optimum location to develop PAC plant. Based on the financial aspect, of the establishment of PAC plants with 15,000 tons per year production capacity, 15 years project period and funding schemes with 65 % provided by bank loans and therest provided by own capital (the highest NPV and IRR from the four alternative schemes). The calculation result is feasible because the NPV is positive and IRR value is greater than the discount rate,consecutively Rp. 22,895,283,616 and 14.16%. The payback period of PAC plant project is 7.218 years.
Keyword: Feasibility Study, Net Present Value, Poly Aluminum Chloride

Judul: Sintesis Polialuminium Klorida Berbahan Dasar Bauksit sebagai Koagulan
Abstrak: Bauxite is a metal resource with the total abundance of 3.47 billion tons in Indonesia in 2011. Bauxite has aluminium content about 45-65%, it makes bauxite has potency as the source of coagulant based on aluminium, polyaluminum chloride (PAC). The synthesis method used for producing PAC was partial hydrolysis using HCl 33% with polymerization times of 24 hours. In this research, characterization of PAC synthetic referring to SNI Quality Requirements 06-3822-1995 with observe the content of aluminium oxide levels, the content of Cl−, pH, spesific gravity, and basicity. This research also examined PAC capability to decrease turbidity in textile waste. Performance test of the coagulant on some textile industry waste water had been tested at pH 6, 7, 8, and 9. Result showed that the best PAC synthetic decreased artificial turbidity to 99.24% at pH 8 with dosage of 1 mL. The same dosage decreased the turbidity in textile waste up to 97.04%.
Keyword: bauxite, coagulant, polyaluminium chloride, textile waste.

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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