Judul: Desorpsi Timbal pada Kerang Darah (Anadara granosa) Menggunakan Ekstrak Air Kulit Jeruk Siam dan Pektinnya
Abstrak: Blood cockles (Anadara granosa) from some sources were reported to contain lead above the threshold as defined by the Standar Nasional Indonesia (SNI). In this experiment, orange peel extract and its pectin were used to reduce the lead content on blood cockles. Aqueous extract orange peels were obtained by crushing the peels and mixed with in proportion of 1:3. Pectin was extracted from the peels using HCl 0.1 N at pH 1.5, and temperature 95 °C for 40 minutes. The pectin yield was 10.18%, equivalent weight 1180.45 g/eq, methoxyl content 6.52% (w/w), galacturonic acid 57.65% (w/w), and degree of estherification 64.24% (w/w). Samples of blood cockles purchased from Pasar Anyar Bogor. The result showed that lead content was below SNI threshold. The samples of blood cockle meat were soaked in lead solution and desorption of lead could be measured. Desorption process were performed by soaking the samples in the extract solution and in 0.2% pectin solution for 60 minutes. The aqueous extract of orange peel reduced lead content by 46%, whereas pectin solution was able to reduced for 48%.
Keyword: Anadara granosa, desorption, lead, pectin, siam orange peel

Judul: Desorpsi timbal pada kerang darah (Anadara granosa) menggunakan ekstrak air kulit jeruk siam dan pektinnya
Abstrak: Kerang darah (Anadara granosa) dari beberapa perairan dilaporkan memiliki kadar timbal (Pb) di atas ambang batas yang ditetapkan oleh Standar Nasional Indonesia (SNI). Pada penelitian ini, kadar Pb dalam kerang darah dikurangi menggunakan ekstrak air kulit jeruk siam dan pektinnya. Ekstrak air diperoleh dengan menghancurkan kulit jeruk siam yang ditambahkan air (1:3). Rektin diekstraksi menggunakan HCl 0.1 N pada pH 1.5, suhu 95 °C selama 40 menit. Rendemen pektin yang dihasilkan 10.18%, bobot ekivalen 1180.45 g/ek, Kadar metoksil 6.52% (b/b), kadar asam galakturonat 57.65% (b/b), dan derajat Sterifikasi 64.24% (b/b). Sampel kerang darah yang diambil dari Pasar Anyar Bogor memiliki kadar Pb di bawah ambang batas SNI. Daging kerang darah direndam dalam larutan Pb agar kadar Pb sebelum dan sesudah desorpsi dapat diukur. Proses desorpsi dilakukan dengan merendam daging kerang dalam ekstrak air kulit jeruk siam dan dalam larutan pektin 0.2% selama 60 menit. Ekstrak air kulit jeruk siam menurunkan kadar Pb sebesar 46%, sedangkan larutan pektin menurunkan kadar Pb sebesar 48%...
Keyword: Anadara granosa, Desoption, Lead, Pectin, Siam orange peel

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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