Judul: The Shelf Life of Complete Feed Wafers contains Corn Husks with Propionic Acid and Salt as Preservatives
Abstrak: Klobot jagung merupakan limbah pertanian yang dapat diolah menjadi wafer pakan komplit karena mengandung serat kasar yang tinggi. Wafer yang tidak langsung dikonsumsi ternak akan disimpan. Penyimpanan wafer juga perlu dilakukan untuk mempertahankan ketersediaan pakan terutama pada musim kemarau. Penelitian ini bertujuan mengevaluasi daya simpan dan kualitas wafer yang diberi asam propionat dan garam serta disimpan selama 6 minggu. Rancangan penelitian yang digunakan adalah Rancangan Acak Lengkap (RAL) faktorial (3 x 3) dengan 3 ulangan. Faktor L adalah lama penyimpanan dengan 3 taraf waktu (0, 3, 6) minggu. Faktor P adalah pengawet dengan 3 perlakuan (kontrol, asam propionat, garam). Parameter yang diuji meliputi organoleptik, kadar air, aktivitas air, serangan serangga, sebaran jamur, wafer durability index, dan biaya produksi. Terdapat interaksi antara lama penyimpanan dan penambahan pengawet pada parameter kadar air, aktivitas air, dan WDI (P<0,05). Lama waktu simpan wafer terbaik adalah 3 minggu dengan penambahan garam yang bernilai kadar air, aktivitas air, dan WDI berturut-turut (13,24 %; 0,636; 70,24 %)., Corn husks are agricultural waste that can be processed into complete feed wafers because they contain high amounts of crude fiber. Wafers that is not directly consumed by cattle will be stored. Wafers storage is also carried out to maintain feed availability, especially during the dry season. This study aimed to evaluate the shelf life and wafers quality added with propionic acid and salt and stored for 6 weeks. The research design used was a factorial Completely Randomized Design (CRD) (3 x 3) with 3 repetitions. The L factor was the storage time with 3 time levels (0, 3, 6) weeks. Factor P was a preservatives with 3 types (control, propionic acid, salt). Parameters tested include organoleptic, water content, water activity, insect attacks, mold distribution, wafer durability index (WDI), and production costs. There was an interaction between storage time and the addition of preservatives on the water content, water activity, and WDI (P<0,05). The best storage time for wafers was 3 weeks and the addition of salt with the values of water content, water activity, and WDI (13,24 %; 0,636; 70,24 %).
Keyword: asam propionat, garam, klobot jagung, penyimpanan, wafer pakan komplit

Judul: Shelf Life Wafers Contain Corn Tumpi at Different  Temperatures and Concentrations of Propionic Acid Preservatives
Abstrak: Wafer merupakan teknologi pengolahan pakan yang dapat mempertahankan kualitas pakan. Daya simpan sangat penting untuk diketahui dengan tujuan menjaga kualitas nutrisi pakan hingga dikonsumsi ternak. Penelitian ini bertujuan menganalisis pengaruh suhu penyimpanan dan penambahan pengawet asam propionat terhadap daya simpan wafer mengandung tumpi jagung. Penelitian ini terdiri dari 3 faktor yaitu suhu penyimpanan (27oC, 40oC, 50oC), lama penyimpanan (1, 5, 10, 15, 20, 25, 30 hari), dan persentase asam propionat (0%, 1%, 2%) dengan 3 ulangan. Data uji fisik di analisis menggunakan analisis ragam (ANOVA), jika berbeda nyata dilanjut dengan uji Duncan. Hasil penelitian menunjukkan bahwa perlakuan suhu, lama penyimpanan, dan persentase asam propionat berpengaruh nyata (P<0,05) terhadap daya simpan wafer. Suhu yang tinggi dapat menurunkan kadar air, aktivitas air, durabilitas, dan meningkatkan bilangan peroksida. Penambahan asam propionat dapat menekan peningkatan kadar air, aktivitas air, serangan serangga, dan bilangan peroksida. Wafer pada suhu 27oC dengan asam propionat 2% memiliki daya simpan yang baik hingga penyimpanan hari ke-25., Wafer is a feed processing technology that can maintain feed quality. Shelf life is very important to know with the aim of maintaining the nutritional quality of feed to livestock consumption. This study aimed to analyze the effect of storage temperature and the addition of propionic acid preservative on the shelf life of wafers containing corn mash. This study consisted of 3 factors, namely storage temperature (27oC, 40oC, 50oC), storage duration (1, 5, 10, 15, 20, 25, 30 days), and percentage of propionic acid (0%, 1%, 2%) with 3 repeats. Physical test data were analyzed using analysis of variance (ANOVA), if significantly different continued with the Duncan test. The results showed that the temperature treatment, storage duration, and percentage of propionic acid had a significant effect (P<0.05) on the shelf life of the wafer. High temperatures could decrease moisture content, water activity, durability, and increase peroxide number. The addition of propionic acid could suppress increases in water content, water activity, insect attack, and peroxide number. Wafers at 27oC with 2% propionic acid had good shelf life until the 25th day of storage.
Keyword: corn tumpi, propionic acid, shelf life, storage temperature, wafer

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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