Judul: Screening Varietas Padi dan Penggunaan Kemasan Plastik Fleksibel untuk Meningkatkan Daya Tahan Simpan Beras: Studi Kasus Beras di Kalimantan Tengah.
Abstrak: Rice is an important commodity because being the staple food of the most of Indonesian people. During storage, the rice can be damaged due to environmental factors as well as postharvest pest. Sitophilus oryzae is postharvest insect pest that attack rice during storage causing quantity and quality losses. The objective of this research is to screening resistance of several local rice variety of Central Kalimantan, study effect of packages on S.oryzae mortality and determine appropriate packaging for rice storage. Eight rice varieties were tested against S.oryzae and then taken three variety (Siam Jurut, Siam Unus and Karang Dukuh) that packaged using “hermetic” laminat, polypropilen (PP) and low density polyetylen (LDPE). Result of the research showed that the lowest index of susceptibility was Siam Jurut, followed by Siam Palun, Siam Palas and Bayar Pahit that were be resistant varieties. Siam Unus had medium index of susceptibility. Rantul, Siam Pandak and Karang Dukuh had high Index of susceptibility. After storage, the resistant group had lower quantity losses, damaged grain and moisture content than susceptible group. The kind of plastic significantly effect to S.oryzae mortality. Total mortality of S.oryzae reached after three day for Siam Jurut, Siam Unus and Karang Dukuh in “hermetic” laminat plastic, six day for Siam jurut in PP plastic, seven day for Siam Unus and Karang Dukuh. In LDPE, total mortality reached after 20 storage day.
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Judul: The Effect of Storage and Packaging on Physical Quality and Moisture Content of Rice Brain
Abstrak: Dedak padi merupakan bahan pakan yang biasa digunakan dalam ransum ternak karena cukup banyak tersedia dan disukai ternak. Kelemahan dedak padi selain mengandung zat anti nutrisi juga daya simpannya yang rendah sehingga mudah menurun kualitasnya. Masalah daya simpan dapat diatasi secara teknologi dengan menambahkan bahan pengawet (aditif asam organik) dan penggunaan kemasan kedap udara (hermetik). Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) faktorial (3 x 4) dengan 4 ulangan, yang terdiri dari faktor lama penyimpanan (0, 30, 60 hari) dan faktor jenis kemasan (karung plastik polipropena, karung goni, kantong plastik polietilena, dan kantong hermetik). Peubah yang diamati yaitu kerapatan tumpukan, kerapatan pemadatan tumpukan, berat jenis, dan kadar air. Data yang diperoleh dari hasil penelitian dianalisis menggunakan analisis ragam ANOVA (Analyses of Variance) dan bila terjadi perbedaan yang signifikan dilanjutkan dengan uji Tukey menggunakan software minitab. Hasil penelitian menunjukkan bahwa perbedaan waktu penyimpanan, jenis kemasan dan interaksi nyata (p<0,05) mempengaruhi nilai kerapatan tumpukan, kerapatan pemadatan tumpukan, berat jenis dan kadar air dedak padi. Selama penyimpanan terjadi penurunan nilai kerapatan tumpukan, kerapatan pemadatan tumpukan, dan berat jenis serta terjadi peningkatan pada nilai kadar air dan jumlah serangan serangga. Perlakuan kantong plastik polietilena dan kantong hermetik seiring dengan penyimpanan (0, 30, dan 60 hari) nyata (p<0,05) lebih tinggi dalam mempertahankan kualitas dedak padi dibanding kemasan karung plastik polipropena dan karung goni. Dapat disimpulkan bahwa penggunaan kantong plastik polietilena dan kantong hermetik lebih baik dalam mempertahankan kualitas dedak padi dibandingkan karung plastik polipropena dan karung goni dengan waktu optimal penyimpanan antara 30 hari sampai kurang dari 60 hari., Rice bran is a feed ingredient commonly used in livestock rations because it is widely available and favored by livestock. The weakness of rice bran in addition to containing anti-nutritional substances is also a low storability so that it is easy to decrease its quality. This problem may be overcome technologically by adding preservatives (organic acid additives) and the use of anti air packaging (hermetic). This research used a factorial completely randomized design (CRD) (3 x 4) with 4 replications, that consist of factor storage time (0, 30, 60 days) and factor type of packaging (polypropyline plastic sacks, burlap sacks, polyethylene bag, and hermetic bag). The variables observed were bulk density, tapped density, true density and moisture content. The data obtained from the results of the research were analyzed using analyses of variance (ANOVA) and if there was a significant difference followed by the tukey test using minitab software. The results of the research showed that the differences in storage, type of packaging and treatment interaction had a significant effect (p<0.05) on bulk density, tapped density, true density and moisture content. During the storage there was a decrease in the value of bulk density, tapped density and true density and increase in the value of moisture content and insect attaction. The treatment of polyethylene bag and hermetic bag during the storage (0, 30, 60 days) was significantly (p<0.05) higher in maintaining the quality of rice bran than polypropyline plastic sacks and burlap sacks. The conclusion is the use of polyethylene bag and hermetic bag is better in maintaining
Keyword: packaging, physical properties, rice bran, storage

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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