Excellence in skilled operation is vital for the efficiency of geothermal power plants. Mount Salak geothermal power plant unit 1-2-3 has consistently produced no less than 180 MWe to the Java-Bali grid since its first commercial operation in 1994, with an equivalent availability factor (EAF) average of 96%. Owing to this long operation period, power plant efficiency must be improved for the sustainable production of electricity. In this study, energy and exergy analysis has been undertaken to ascertain the amount of energy that is used in the power plant's current condition, and to determine the plant's overall system losses. Research was carried out by collecting data relating to temperature, pressure, and mass flow rate. Data were analyzed using the control volume to assess the thermal and mass balance and ascertain the value of exergy. Analysis was conducted theoretically and compared with results calculated by Engineering Equation Solver (EES) software. The results showed that from 1069,90 MWe in steam energy entering the system, the total amount of exergy was 302.42 MWe. Mount Salak geothermal power plant unit 1-2-3 had an overall first law efficiency of 16.75% and an overall second law efficiency of 59.27%. The greatest losses  27.84% of the total exergy  were in the condensers. This was caused by the quality of cooling water entering condensers, which was in turn a result of cooling tower performance. Results suggest that turbine unit 1 should be investigated further to determine causes of decreased capacity.

I n t e r n a t i o n a l J o u r n a l o f N u s a n t a r a I s l a m

Artikel ini membahas prinsip bagi hasil dalam skema mudharabah di perbankan syariah dan permasalahan yang terdapat di dalamnya dengan metode deskriptif-kualitatif melalui studi kepustakaan dan eksploratif literatur. Skema mudharabah biasanya diterapkan pada produk pembiayaan dan investas yang melibatkan dua pihak: shahib al-maal dan mudharib. Kedua belah pihak bekerjasama untuk mendapatkan keuntungan yang akan dibagikan sesuai dengan nisbah yang telah disepakati di awal akad. Apabila terjadi kerugian finansial, shahib al-maal akan menanggung semuanya, tetapi jika disebabkan oleh kelalaian pengelola modal maka kerugian tersebut harus ditanggung oleh mudharib. Hasil penelitian menunjukkan bahwa dalam akad mudharabah mayoritas bank syariah menerapkan prinsip revenue-sharing yang secara tidak langsung direstui oleh Fatwa DSN 07/2000. Penerapan prinsip ini dapat memicu timbulnya rasa ketidakadilan karena bagi hasil dihitung berdasarkan laba kotor yang lebih menguntungkan pihak shahib al-maal dan kurang menguntungkan bagi mudharib. Kondisi ini membuat nasabah kurang termotivasi untuk memilih bank syariah ketimbang bank konvensional. Dilihat dari perspektif fiqh, bagi hasil dihitung berdasarkan keuntungan bersih sebagaimana diterapkan pada prinsip profit/loss-sharing, yang penerapannya juga direkomendasikan oleh OKI. Pada akhirnya, penyempurnaan pada Fatwa DSN 07/2000 perlu dilakukan untuk memberikan rasa keadilan bagi semua entitas mudharabah: shahib al-maal dan mudharib. [This article was created to discuss the principle of profit-sharing in the mudharabah scheme in Islamic banking and the problems contained therein using descriptive-qualitative methods through library study and literature exploratory. Mudharabah schemes are usually applied to financing and investment products that involve two parties: shahib al-maal and mudharib. Both parties collaborate to get profits which will be shared according to the nisbah agreed at the beginning of the contract. If there is a financial loss, shahib al-maal will bear everything, but if it is caused by the negligence of the capital-user then the loss must be borne by the mudharib. The results showed that in the mudharabah contract, the majority of Islamic banks apply the principle of revenue-sharing which is indirectly blessed by Fatwa DSN 07/2000. The implementation of this principle could trigger a sense of injustice because the profit-sharing is calculated based on gross profit which is more beneficial for the shahib al-maal and less profitable for the mudarib. This condition makes customers less motivated to choose Islamic banks rather than conventional banks. From the perspective of fiqh, profit-sharing is calculated based on net profit as it’s applied to the principle of profit/loss-sharing as well as recommended by the OIC. At the end, improvements to the Fatwa 07/2000, needs to be done to provide a sense of justice for all mudharabah entities: shahib al-maal and mudharib.]

Batik waste can increase water characteristics, such as turbidity, color and total suspended solids (TSS). Thus, an efficient technique for separating Batik from the liquid to decrease these characteristics is needed. The aim of the current study was to understand the results of flotation using electrolysis and to investigate the bubble characteristics that influence the results of the flotation of Batik waste. Flotation studies have been conducted using electrolysis to produce bubbles to separate batik synthetic dye from the liquid. Research conducted with 316L stainless steel electrodes, inside a 100 cm tall acrylic pipe with an inner diameter of 8.4 cm and a voltage variation of 10, 15 and 20 V. Batik waste was mixed with distilled water. Commercial alum powder [aluminum sulfate, Al 2 (SO 4 ) 3 .14H 2 O, that is 17% Al 2 O 3 ] as the reagent was added to coagulate Batik waste in a ratio of 1 gram per 10 ml of Batik waste. The results showed that flotation of Batik waste can be used to separate Batik waste with the addition of alum. Alum was shown to be capable of acting as a collector in this type of waste separation. The results showed that flotation using electrolysis could be an effective method for reducing turbidity, color and TSS.

In the study of classical Jurisprudence, the mudhârabah contract is the same contract which has no guarantee provisions in it. Therefore, in the mudhârabah contract there is no need for collateral, because the mudhârabah contract is a contract that is based on the element of trust (trust) so there is no need for guarantees given by customers to banks / Islamic financial institutions. The purpose of this study was to analyze maqâshid al-sharia on the application of collateral to the mudhârabah contract in Islamic Financial Institutions. The method of approach used in this study is normative juridical research with the nature of descriptive analysis. The type of data used in this study are primary and secondary data types. This research is classified as a type of qualitative research. The results show that collateral in the mudhârabah contract serves to avoid deviations from the fund management customer so that they do not play around in managing the mudhârabah financing fund, and guarantees are not necessary and mandatory conditions on every Mudhârabah financing. Therefore, LKS may set the guarantee to clients which serves to avoid the moral hazard of the mudharib negligent or not according to the contract, which is in line with the values of the benefit in Islamic transactions system.