Judul: Evaluasi Kinerja Peningkatan Kapasitas Pengomposan dari Campuran Blotong, Bagas, dan Abu Ketel
Abstrak: Composted filter cake, bagasse, and boiler ash on laboratory scaled which used aerated pile method had generated an optimum initial C/N and resulted the best compost quality. Meanwhile in order to be applied directly in industrial scale, the evaluation of laboratory scaled co-composting performance was needed along with increased processing capacity. The aim of this study was to compare larger scale of co-composting performance evaluation with laboratory scale. Capacity enhancement was done by increasing the capacity process from laboratory scaled of 5 kg to 100 kg. The evaluated performance parameters in co-composting were composting rate and the effect of aeration during composting. While constant factors, as same as capacity of 5 kg’s, were reactor geometrical congruency, initial C/N and aeration treatment. Compost mixture had initial C/N value of 50 and active aeration treatment of 0.4 L/min.kg was given in for 1 hour per day in the first week. The result showed that there were no any significant differences of composting rate between 5 kg and 100 kg. Besides, active aeration did not give significant effect to process condition and the composting rate in 100 kg scaled co-composting. Financial analysis of composting was able to bring profits based on the equation of B/C ≥1.
Keyword: evaluation of capacity process, co-composting, C/N, capacity enhancement, aeration

Judul: Kajian Peningkatan Kapasitas Proses Co-Composting Blotong dan Abu Ketel
Abstrak: Co-composting at industrial scale can be applied for utilization of filter cake and boiler ash. For applying in industrial scale, study on composting performance in larger capacity was needed. The purpose of this research was to study the performance of composting process in large scale compared with laboratory scale as reference for industrial implementation. The parameters in scale increasing consist of the C/N decrease rate and the effect of aeration for 60 days of composting. Increased composting capacity was done by increasing the capacity of 5 kg to 120 kg. Constant factor in the increase in capacity is congruency geometry, aeration rate and the value of C/N beginning 40. The result showed that composting process at 120 kg scale was not different from 5 kg scale, in which the temperature formed in mesophilic phase, pH level was neutral and optimum moisture content. The rate of decrease C/N was, 1.3675 / day with yield of 68.97% and the estimated time of compost for 20 days. There was no effect of 14 aeration during compost of 120 kg at a rate of decrease C/N. B/C ratio in the analysis of business of industrial compost capacity was 1.42, that means it could be implemented.
Keyword: boiler ash, filter cake, increased capacity, co-composting

Judul: Invers Drazin dari Matriks Toeplitz Singular
Abstrak: Matriks Toeplitz adalah matriks yang setiap unsur pada diagonal utama bernilai sama dan setiap unsur pada subdiagonal yang bersesuaian dengan diagonal utama juga bernilai sama. Matriks singular adalah matriks yang tidak bisa ditentukan inversnya. Akan tetapi, dapat diupayakan untuk ditentukan inversnya menggunakan invers matriks yang diperumum. Invers Drazin merupakan salah satu jenis invers matriks yang diperumum. Pada karya ilmiah ini ditentukan invers Drazin dari matriks Toeplitz singular dengan menggunakan metode Leverrier Faddeev. Kemudian, ditentukan invers Drazin dari matriks Toeplitz singular yang direpresentasikan sebagai penjumlahan segitiga bawah dan segitiga atas matriks Toeplitz berdasar pada teorema Gohberg dan Semencul., Toeplitz matrix is a matrix in with element on the main diagonal has the same value and on the subdiagonal corresponding to the main diagonal also has the same value. Singular matrix is a matrix that has no inverse. However, it can be attempted to determine the inverse using a generalized inverse matrix. Inverse Drazin is a type of generalized matrix inverse. This paper discussed the inverse Drazin for a singular Toeplitz matrix using the Leverrier Faddeev method. Then, the Drazin inverse of the singular Toeplitz matrix which is represented as a sum of products of lower and upper triangular Toeplitz matrix based on Gohberg and Semencul theorem.
Keyword: inverse Drazine, singular Toeplitz matrix