Judul: Quality of Frass from Samia cynthia ricini Silkworm by Feeding Castor Leaves Using Different Activators
Abstrak: Limbah frass ulat sutra eri (Samia cynthia ricini) kurang dimanfaatkan, pemeliharaan 20.000 – 25.000 larva menghasilkan frass sekitar 500 kg. Frass dapat digunakan sebagai bahan pupuk organik untuk meningkatkan unsur hara tanah. Penelitian ini bertujuan menganalisis kualitas pupuk frass ulat sutra eri dengan pemberian pakan daun jarak kepyar dengan aktivator EM4 dan PGPR. Peubah yang diamati dari pupuk frass dengan penambahan EM4 dan PGPR, yaitu sifat fisik dan kimia selama 21 hari yang diamati pada hari ke-0, 7, 14, dan 21, serta uji efektivitas pupuk frass pada tanaman kangkung selama 28 hari. Hasil penelitian menunjukkan sifat fisik pupuk frass memenuhi standar SNI pada pH berkisar 4-9, tekstur remah, dan aroma sedikit asam. Penambahan EM4 dan PGPR meningkatan unsur N dan K, sedangkan P dan rasio C/N mengalami penurunan. Penggunaan pupuk frass pada tanaman kangkung menunjukkan hasil tidak berbeda nyata (P>0,05) terhadap tinggi tanaman, diameter batang, jumlah daun, dan bobot segar. Pupuk frass berpotensi menggantikan pupuk kimia berdasarkan peubah yang diamati., Eri silkworm (Samia cynthia ricini) frass waste is underutilized, rearing 20,000 – 25,000 larva produces around 500 kg of frass. Frass can be used as an organic fertilizer to increase soil nutrients. This research aims to analyze the quality of eri silkworm frass fertilizer by feeding it with castor leaves with EM4 and PGPR activators. The variables observed from frass fertilizer with the addition of EM4 and PGPR, included the physical and chemical properties for 21 days which were observed on days 0, 7, 14, and 21, as well as testing the effectiveness of frass fertilizer on water spinach plants for 28 days. The research results show that the physical properties of frass fertilizer meet SNI standards at a pH ranging from 4-9, a crumbly texture, and a slightly sour aroma. The addition of EM4 and PGPR increased the N and K elements, while P and the C/N ratio decreased. The use of frass fertilizer on water spinach plants showed that the results were not significantly different (P>0.05) on plant height, stem diameter, number of leaves and fresh weight. Frass fertilizer has the potential to replace chemical fertilizer based on the observed variables.
Keyword: EM4, Samia cynthia ricini, castor leaves, eri silkworm frass, PGPR

Judul: Microbiological Properties and Antioxidant Activity of Eri Silkworm Pupae (Samia cynthia ricini) Flour with Different Particle Size
Abstrak: Pupa ulat sutra Eri (Samia cynthia ricini) memiliki nilai gizi dan sifat antioksidan yang dapat dijadikan sebagai produk pangan berupa tepung. Sebagai produk pangan, diperlukan uji analisis mikrobiologi sehingga diketahui kelayakannya. Sifat Mikrobiologi dianalisis dengan menghitung Angka Lempeng Total, E. coli, S. aureus dan Salmonella sp. Sementara itu, adanya proses pengayakan tepung dengan tujuan menghomogenkan ukuran partikel dapat memengaruhi aktivitas antioksidan. Maka dari itu, nilai aktivitas antioksidan pada tepung sutra Eri dengan ukuran partikel 80 mesh dan 60 mesh diuji melalui aktivitas penghambatan DPPH (2.2-Diphenyl-1-picrylhydrazyl) dan kapasitas antioksidan. Analisis data menggunakan rancangan acak lengkap (RAL) dan uji T-Independen. Hasil menunjukkan bahwa nilai ALT, E. coli dan Salmonella sp. telah memenuhi ketentuan standar SNI 3751:2009. Jumlah sel S. aureus pada tepung ialah <105 koloni/g, sehingga mengindikasikan bahwa jumlah cemaran tidak melebihi ambang batas. Selain itu, analisis aktivitas antioksidan kedua tepung tergolong kuat meskipun ukuran partikel tepung pupa sutra Eri yang berbeda tidak memberikan pengaruh nyata., Eri silkworm pupae (Samia cynthia ricini) have nutritional and antioxidant values that can be used as food products in the form of flour. As a food product, it is necessary to test its microbiological properties so that its feasibility is known. Microbiological properties were analyzed by calculating the Total Plate Count, E. coli, S. aureus and Salmonella sp. Meanwhile, the process of sifting flour with the aim of homogenizing the particle size will affect the antioxidant activity. Therefore, the antioxidant activity in Eri silk flour with particle sizes of 80 mesh and 60 mesh was tested through DPPH inhibition activity and antioxidant capacity. Data analysis used a completely randomized design (CRD) and independent T-test. The results showed that the value of the TPC, E. coli and Salmonella sp. has met the standard provisions of SNI 3751:2009. The number of S. aureus cells was <105 colonies/g which indicated that the amount of contamination did not exceed the thresholdhe analysis of the antioxidant activity was classified as strong although the different particle size did not have a significant effect.
Keyword: antioxidant, flour, microbiological properties, pupae, Samia cynthia ricini

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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