Deskripsi Pemahaman Konsep Siswa pada Materi Kelarutan dan Hasil Kali Kelarutan Kelas IX IPA SMA

The purpose of the research was to describe the student's understanding concept in solubility and solubility product of grade IX IPA SMA Negeri 1 Sungai Ambawang. The form of the research was descriptive and the method of this research was case study that involved 54 students. The instrument used were a test of learning outcome in the form of essay and interview guide. The result showed most students had an understanding of the concept in determining; (1) the mass of dissolved salts was 48.15% with category: enough; (2) a Ksp solution was 46.29% with category: enough; (3) solubility in common ion was 81.48% with category: less; (4) pH in common ion was 55.56% with category: less; and (5) the forming of precipate was 61.11% with category: enough. The student's understanding concept in average was 46.1 with category: enough

Efektifitas Kijing Air Tawar ( Pilsbryoconcha Exilis ) Sebagai Biofilter Dalam Sistem Resirkulasi Terhadap Laju Penyerapan Amoniak Dan Pertumbuhan Ikan Lele Sangkuriang (Clarias Gariepinus)

Tujuan dari penelitian ini adalah untuk mempelajari pengaruh penggunaan kijing air tawar (Pilsbryoconcha exilis) terhadap perbaikan kualitas air dan laju pertumbuhan lele sangkuriang. Penelitian ini menggunakan Rancangan Acak Lengkap dengan empat perlakuan dan tiga ulangan. Penelitian menggunakan perbedaan jumlah hewan kijing air tawar yaitu 100, 150, 200 ekor/ keranjang berukuran 0,6 m3 dan perlakuan kontrol yaitu tanpa menggunakan perlakuan sistem resirkulasi dan tanpa penambahan kijing air tawar. Parameter utama dalam penelitian ini adalah pertumbuhan ikan dan konsentrasi amoniak, dengan parameter pendukung antara lain yakni suhu, pH, dan oksigen terlarut. Hasil penelitian menunjukkan bahwa penambahan kijing air tawar berpengaruh terhadap pertumbuhan dan kelangsungan hidup ikan lele sangkuriang. Pertumbuhan mutlak tertinggi terdapat pada perlakuan 200 individu dengan berat 19.71 gr dan tingkat kelangsung hidup tertinggi terdapat perlakuan 200 individu (80.14 %). Hasil penelitian juga menunjukan bahwa penambahan kijing air tawar dengan jumlah yang berbeda memberikan pengaruh nyata terhadap penurunan amoniak. Berdasarkan hasil uji Beda Nyata Terkecil (BNT) perlakuan dengan penambahan kijing air tawar sebanyak 200 ekor/ keranjang berukuran 0,6 m3merupakan perlakuan terbaik dalam penurunan amoniak pada sistem resirkulasi

Some Aspects of Spherical Symmetric Extremal Dyonic Black Holes in 4d N=1 Supergravity

In this paper we study several aspects of extremal spherical symmetric black hole solutions of four dimensional N=1 supergravity coupled to vector and chiral multiplets with the scalar potential turned on. In the asymptotic region the complex scalars are fixed and regular which can be viewed as the critical points of the black hole and the scalar potentials with vanishing scalar charges. It follows that the asymptotic geometries are of a constant and non-zero scalar curvature which are generally not Einstein. These spaces could also correspond to the near horizon geometries which are the product spaces of a two anti-de Sitter surface and the two sphere if the value of the scalars in both regions coincides. In addition, we prove the local existence of non-trivial radius dependent complex scalar fields which interpolate between the horizon and the asymptotic region. We finally give some simple {\lC}^{n}-models with both linear superpotential and gauge couplings.Comment: 17 pages, no figure. Added an author. Major revision: typos and grammar corrected, some statements modified, added a section about local existence of scalar fields. Accepted for publication in Int J Mod Phys