JENIS DAN KELIMPAHAN BENIH LOBSTER (PANULIRUS spp.) BERDASARKAN KEDALAMAN DI PERAIRAN DESA RANOOHA RAYA, KECAMATAN MORAMO, KABUPATEN KONAWE SELATAN

Benih lobster merupakan stadia post larva yang bentuknya sudah menyerupai lobster dewasa namun belum memiliki pigmen dan rangka luar yang keras kemudian bersifat planktonis dan melayang-layang dalam air. Penelitian ini bertujuan untuk mengetahui kelimpahan benih lobster (Panulirus spp.), hubungan kelimpahan benih lobster dengan kedalaman serta parameter kualitas perairan. Pengambilan data dilakukan pada bulan Februari-September 2019, bertempat di Perairan Desa Ranooha Raya, Kabupaten Konawe Selatan. Pengambilan data dilakukan pada 3 titik stasiun pengamatan dengan menggunakan metode deskriptif eksploratif dan analisis data menggunakan analisis korelasi. Kelimpahan benih lobster (Panulirus spp.) diperoleh dengan menggunakan alat tangkap pocong (shelter) sedangkan pengambilan data kualitas perairan dilakukan secara in situ. Hasil penelitian menunjukkan bahwa kelimpahan benih lobster tertinggi yaitu pada stasiun II (kedalaman 4 meter) berjumlah 221 individu dan kelimpahan terendah pada stasiun I (kedalaman 6 meter) berjumlah 155 individu. Jenis benih lobster yang ditemukan yaitu jenis benih lobster mutiara (Panulirus ornatus) dan jenis benih lobster pasir (Panulirus homarus). Persentase kelimpahan relatif tertinggi yaitu jenis benih lobster mutiara sebesar 75% dan persentase kelimpahan relatif terendah jenis benih lobster pasir sebesar 55,56%. Hasil analisis korelasi hubungan kelimpahan benih lobster berdasarkan kedalaman diperoleh nilai hubungan yang kuat. Parameter kualitas perairan masih mendukung untuk kehidupan benih lobster seperti arus, suhu, kedalaman, kecerahan, pH, salinitas dan DO (Dissolve Oxygen). Parameter kecepatan arus merupakan faktor yang sangat mempengaruhi keberadaan benih lobster (Panulirus spp.) di perairan.Kata Kunci: Benih Lobster (Panulirus spp.), Kelimpahan, Kedalaman Perairan, Parameter Perairan.

Crystal structure of spinel-type Li0.64Fe2.15Ge0.21O4

Spinel-type Li0.64Fe2.15Ge0.21O4, lithium diiron(III) germanium tetraoxide, has been formed as a by-product during flux growth of an Li–Fe–Ge pyroxene-type material. In the title compound, lithium is ordered on the octahedralBsites, while Ge4+orders onto the tetrahedralAsites, and iron distributes over both the octahedral and tetrahedral sites, and is in the trivalent state as determined from Mössbauer spectroscopy. The oxygen parameteruis 0.2543; thus, the spinel is close to having an ideal cubic closed packing of the O atoms. The title spinel is compared with other Li- and Ge-containing spinels.

Estimating Electrical Conductivities of CaO-MgO-Al2O3-SiO2 Using Ion-Oxygen Parameter

Electrical conductivity of molten slags is one of the most important physicochemical properties and it also has a close relationship to the structure of slag. This article focused on the basic slag system CaO-MgO-Al2O3-SiO2 and made estimations for electrical conductivity. Ion-oxygen parameter was selected to describe the relationship between electrical conductivity with compositions. Moreover, the interaction between composition and temperature was embodied in the final model formula. It was shown that increasing CaO and MgO contents enhanced the ability for electric conduction. Moreover, with a higher temperature, the change of electrical conductivity with ion-oxygen parameter was more remarkable. This model gives reasonable prediction of the electrical conductivity for the slags studied with the mean deviation of 14.3%. Thus, this model would provide a feasible tool for industry to predict and optimize the electrical conductivity of slag system.

The crystal structure of brunogeierite, Fe2GeO4 spinel

Brunogeierite, Fe2GeO4, a = 8.4127(7) Å, V = 595.4(1) Å3, is a rare germanate spinel from Tsumeb, Namibia. Its structure has been refined to an R index of 2.2%. The oxygen parameter, u, is 0.2466(1), indicating nearly ideal cubic close-packing of oxygen atoms. There is exact agreement between the observed a unit-cell dimension and that calculated from the observed Ge–O and Fe–O bond lengths. The cations Ge and Fe are fully ordered at tetrahedral (A) and octahedral (B) sites, respectively, in keeping with synthetic germanate spinels, all of which are fully-ordered normal spinels.