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: Perbandingan Kebutuhan Koagulan Al2(SO4)3 dan PAC Untuk Pengolahan Air Bersih di WTP Sungai Ciapus Kampus IPB Dramaga
Abstrak: Water treatment plant (WTP) IPB mengolah air dari Sungai Ciapus melalui proses penjernihan air sebelum didistribusikan kepada konsumen. Jenis koagulan yang digunakan adalah Al2(SO4)3 (aluminium sulfat) atau tawas dan Polyaluminium Chloride (PAC). Penelitian ini bertujuan untuk membandingkan kualitas air dengan menggunakan koagulan Al2(SO4)3 dan PAC di WTP Sungai Ciapus kampus IPB Dramaga serta mengidentifikasi dosis optimum dari koagulan tawas dan PAC. Penelitian ini menggunakan metode jar test dan SNI untuk analisis parameter fisika dan kimia air. Berdasarkan hasil penelitian yang dilakukan, PAC lebih baik dibandingkan tawas dengan dosis optimum sebesar 20 ppm yang menghasilkan kekeruhan sebesar 0.22 NTU, TSS sebesar 1 mg/l dan TDS sebesar 150 mg/l. Dengan dosis optimum tawas sebesar 20 ppm diperoleh nilai kekeruhan 0.49 NTU, TSS 0 mg/l dan TDS sebesar 164 mg/l. Biaya rata – rata untuk penggunaan koagulan tawas dan PAC adalah sebesar Rp. 95/m3 dan Rp 215/m3, sedangkan rata – rata nilai efisiensi penggunaan koagulan tawas dan PAC adalah 91.34% dan 83%. Hasil penjernihan air dengan kedua koagulan memenuhi kriteria baku mutu kualitas air bersih yang berlaku di Indonesia.
Keyword: jar test, koagulan, PAC, pengolahan air bersih, tawas

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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