Judul: Kandungan Logam Berat Kromium (Cr) dalam Air, Sedimen, dan Ikan Nila (Oreochromis niloticus) serta Karakteristik Biometrik dan Kondisi Histologisnya di Sungai Cimanuk Lama, Kabupaten Indramayu
Abstrak: The heavy metal chromium which contained in batik wastewater will cause the water gets polluted if it is discharged directly to the Cimanuk Lama River, Indramayu District without any treatment. This is happened because the heavy metal chromium dissolved in the water, settled in sediment, and accumulated in fish body. The negative impact of chromium heavy metal to fish is lead to stress, disruption of physiological processes, affecting the health, and lead to death. There will also accumulate chromium heavy metal in the body so it is not feasible consumed by the humans because endangering the health. The fish that are found in the Cimanuk Lama River was Nile Tilapia. The Nile Tilapia (Oreochromis niloticus) will accumulate chromium heavy metal in the body and cause tissue damage and impaired growth. The objectives of the study were to review the content of the heavy metal chromium in water, sediment, nile tilapia fish (O. niloticus), and biometric characteristic and their histological condition in the Cimanuk Lama River, Indramayu District. This information can be used as a reference to consume Nile Tilapia and to manage the Cimanuk Lama River, Indramayu District by the community. This study was conducted from February to April 2014. Sampling for the water and the content of chromium heavy metal every month at three observation stations. Station 1 is the area of the river there is no industrial activity and residential areas, Station 2 is located around the batik industry area and residential areas, and station 3 is downstream of the basin after the batik industry activities, residential areas, and agricultural activities. Sampling of Nile Tilapia using gill net with mesh size of 1,5 inch. Nile Tilapia which is used in this study come from the catch and which are cultivated in floating cage by the fisherman. The result showed that content of chromium in the water was range from 0,85– 0,91 mg L-1, in sediment was 27,39–37,12 mg kg-1 and in body fish was 18,01–91,76 mg kg-1. There patterns isometric, allometric negative, and allometric positive. Condition factor (1,618–2,587), gonado somatic index (0,086–2,318 %), fecundity (568–1192 grains/ individual), egg diameter (0,358–0,467 μm), hepato somatic index (0,621–2,063 %) and relative weight gill (4,022–6,102 %). Gills and liver damage of nile tilapia fish classified as low to high level. Batik industry activity arround the Cimanuk Lama River, Indramayu District of contributed significantly to chromium heavy metal pollution.
Keyword: Cimanuk Lama River, histological condition, Nile Tilapia fish, chromium heavy metal, biometric characteristic

Judul: Kerusakan Hati Ikan Nila (Oreochromis Niloticus Linnaeus, 1758) Di Sungai Cimanuk Lama Indramayu Dan Di Media Uji Laboratorium Yang Terpapar Kromium
Abstrak: Pemanfaatan logam berat kromium pada saat ini telah mencakup seluruh aspek kehidupan manusia dan lingkungan. Selama kurun waktu beberapa tahun, kromium telah banyak digunakan di berbagai bidang, salah satunya dalam bidang industri batik. Logam berat kromium yang terkandung dalam limbah cair batik apabila dibuang tanpa adanya pengolahan akan mengakibatkan pencemaran Sungai Cimanuk Lama, Indramayu. Hal ini dikarenakan logam berat kromium akan terlarut di dalam air, terendap di dalam sedimen, dan terakumulasi di dalam tubuh ikan. Ikan yang telah terpapar logam berat kromium tidak layak untuk dikonsumsi karena membahayakan kesehatan manusia. Ikan yang banyak ditemukan di Sungai Cimanuk Lama adalah ikan nila (Oreochromis niloticus). Ikan nila yang hidup di sekitar Sungai Cimanuk Lama berpotensi terkontaminasi logam berat kromium dari limbah cair batik dan mengakibatkan kerusakan jaringan serta pertumbuhannya akan terganggu. Tujuan dari penelitian ini adalah untuk mengetahui dan mengkaji kandungan logam berat kromium pada ikan nila (Oreochromis niloticus) dan air, serta mempelajari tingkat kerusakan spesifik organ hati ikan nila (Oreochromis niloticus) di Sungai Cimanuk Lama, Kabupaten Indramayu dan membandingkannya dengan skala laboratorium. Informasi dari hasil penelitian ini dapat dijadikan acuan oleh masyarakat dalam mengkonsumsi ikan nila dan dapat dijadikan dasar untuk pengelolaan Sungai Cimanuk Lama, Indramayu. Penelitian ini dilaksanakan pada bulan April 2015 di Sungai Cimanuk Lama, Kabupaten Indramayu. Selain itu juga, dilaksanakan penelitian di laboratorium untuk melakukan uji pendahuluan, uji toksisitas letal dan toksisitas subletal dari logam berat kromium terhadap ikan nila. Pengambilan contoh dilakukan di tiga stasiun yang terletak di badan sungai yaitu : sebelum kegiatan industri (stasiun 1), di badan sungai sekitar kegiatan industri (stasiun 2), dan di badan sungai setelah kegiatan industri (stasiun 3). Pada masing-masing stasiun dilakukan pengambilan contoh air dan ikan nila. Hasil penelitian menunjukkan bahwa kandungan logam berat kromium di dalam air berkisar 0.012-0.11 ppm, tubuh ikan nila (daging) 1.24-2.80 mg kg-1, hati ikan nila 3.08-3.82 mg kg-1. Nilai toksisitas letal (LC50-96 jam) Cr6+ pada ikan nila yaitu sebesar 61.2 ppm. Hati ikan nila pada Sungai Cimanuk Lama memiliki tingkat kerusakan lebih tinggi apabila dibandingkan dengan ikan yang dipelihara di media uji.
Keyword: Ikan nila, logam berat kromium, LC50-96 jam, deposit logam berat kromium, Sungai Cimanuk Lama

Judul: The use of homotopy perturbation methode to solve fuzzy volterra  integral equations
Abstrak: Most phenomena in nature can be explained in mathematical models, such as fuzzy volterra integral equation. The fuzzy volterra integral equation is a nonlinear integral problem, which is usually dificult to solve by an analytical solution. In this paper, fuzzy volterra integral equation is solved using perturbaion homotopy method, which can be written as a power series in p and satisfies a certain homotopy fuction. This manuscript discuss two case studies, i.e. the case of linear and trigonometric kernel function. The result shows that greater approximation order being used, the wider convergence solution area wil be.
Keyword: