Judul: Rancangan dan Uji Teknis Mesin Pendingin Jet Uap
Abstrak: Kebutuhan energi yang semakin meningkat memaksa manusia untuk mencari bentuk energi yang lain. Salah satu sumber energi yang banyak tersedia di muka bmi ini adalah energi Matahari dan energi Air.
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Judul: Rancangan dan Uji Performasi Mesin Pendingin Jet Uap
Abstrak: Telah dikenal beberapa sistem pendinginan, diantaranya adalah sistem kompresi, absorbsi, termoelektrik, cryogenik dan sistem pendinginan jet uap. Sampai saat ini sistem pendinginan jet uap masih belum digunakan terutama pada pengolahan pasca panen di negara kita. Tujuan dari penelitian ini adalah untuk merancang mesin pendingin jet uap yang menggunakan air sebagai refrigerannya dan uap air sebagai fluida penggerak sistem, sekaligus menentukan penampilan alat tersebut untuk mengetahui performansi dan karakteristiknya. Cara kerja sistem pendinginan jet uap hampir sama dengan sistem pendinginan kompresi sentrifugal. Fungsi yang sama dari kompresor sentrifugal digantikan dengan menggunakan E-jektor. Selain Ejektor, komponen utama mesin pendingin jet uap adalah Evaporator dan Kondensor. Adapun Ejektor terdiri dari dua komponen utama, yaitu Nosel dan Difuser. Nosel yang dibuat berbentuk konvergendivergen dengan panjang 55.0 mm dan diameter 'throat 8.5 mm. Sedangkan Difuser yang dibuat mempunyai panjang 200.4 mm dan diameter 'throat' 10.3 mm serta berbentuk konvergen-divergen. ...
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Judul: Mercury Toxicity and It’s Effect on Histopathology Change of Nile Tilapia (Oreochromis niloticus).
Abstrak: Nile tilapia (Oreochromis niloticus) is one of fish species that oportunity to contaminated with mercury. The effects of pollutants can damage living organisms organs and can cause death. The effects caused mercury had acute or chronic character. The aims of this study are to determine threshold and acute toxicity of mercury chloride (HgCl2) of Nile tilapia (Oreochromis niloticus), to assess the effect of mercury chloride (HgCl2) on several biometric parameters (survival, growth rate of average daily weighted, liver condition, bile and reproductive variability of Nile tilapia (Oreochromis niloticus), assess the level of damage to the histological structure of the gills, liver and kidney of Nile tilapia (Oreochromis niloticus) caused mercury chloride (HgCl2) exposure. This study was conducted from February to June 2013. Nile Tilapia (Oreochromis niloticus) were used in this study were female with average weight 20 grams or 11-13 cm length range. Toxicant materials used in this study was mercury chloride (HgCl2). Fish were reared in each aquarium 60x40x30 containing 48 liters of water. This study consists of three stages: a preliminary test, acute test, and sub-chronic test. To determine the changes in biometric condition of tilapia approximated by measuring the survival rate (SR), the growth rate of average daily weight , the content of mercury in the fish organs, hepatosomatic index (HSI), the relative bile volume (VER), gonadal soamtic index (IKG), fecundity and oocit diameter, tissue damage caused by mercury in fish organs by making histological preparations stained with hematoxylin and eosin. The median lethal concentration (96 hr, LC50) of Mercury Chloride was calculated as 1,64 mgL--1.The survival rate was highest in the control treatment (46,67 %) . Mercury chloride with concentration 0.196 mgL--1 show significant effect to changes HSI and relative bile volume, and oocyte diameter of Nile tilapia (p < 0,05). Mercury chloride with a concentration of 0,164 mgL-1 and 0,196 mgL-1 have not a significant effect on the growth rate of weight, gonadal somatic index and fecundity of Nile tilapia (p > 0,05). Mercury chloride cause damage to gills (hyperplasia, hypertrophy, proliferation and neukrosis), liver (hyperplasia, hemorhage, shrinkage of hepatocytes, proliferation and neukrosis) and kidney (hyperplasia, hemorrhage, shrinkage of the glomerulus, proliferation and neukrosis).
Keyword: Nile tilapia, Hepatosomatic indexs (HSI), histopathology