Judul: Desain proses pengolahan pada agroindustri kopi robusta menggunakan modifikasi teknologi olah basah berbasis produksi bersih
Abstrak: Coffee in Indonesia included 5 main crops commodities, and 10 main export commodities. Since 2008, Indonesia is the third exporter countries after Brazil, and Vietnam. Coffee has been shown to have definitely beneficial for Indonesian farmer as source of income, and contributes for regional development, so its sustainability should be maintained. One of constraints faced by farmers is low quality of coffee beans due to post-harvest handling. Most coffee producer in Indonesia is smallholder Robusta coffee which used to dry process for coffee berry. Application of wet process is more sophisticated than the dry process, but leads to better quality coffee bean, though need high input of water, and produce wastewater that can pollute the environment. It should be designed coffee processing based on clean production to minimize, and prevent the wastewater generated from processing. Development of processing technologies based on cleaner production is a part of sustainability development strategies on smallholder coffee agroindustry. Therefore, the main objective of this research is to design sustainability of smallholder coffee processing using wet technology that has quality oriented to improve farmer productivity, and incomes without dismissing social, and environmental interests. In particular, the general objective is achieved through several phases with their aims as follows; (1) to formulate coffee agroindustry sustainability framework based on economic, environmental, social, and institutional indicators, (2) to determine the sustainability status of smallholder coffee agroindustry, (3) to modify wet technology on Robusta coffee processing by water minimizing, (4) to design of waste treatment system on smallholder coffee agroindustry, (5) to formulate the structure of smallholder coffee agroindustry development which based on cleaner production. Research is conducted through several stages in the research field of coffee plantation area (Sidomulyo village, Jember Regency), laboratories (Jember University, and AWMC, The University of Queensland), and pilot plant unit (Indonesian Coffee and Cocoa Research Institute). Sustainability analysis showed the value of sustainability is 58,94% (sustainable enough) with 10 main leverage factors. Modified wet technology through water minimization can reach optimum levels at 2,987 – 3,345 m3/tonne of coffee berry. Within this volume, the quality of green coffee could be maintained, and wastewater minimized until 67% compared to conventional wet processing. Waste treatment designed of coffee processing have been done through reduce, reuse, and recycle (3R) to obtain the economic value of by-products. Economic analysis showed smallholder coffee agroindustry which applied modified wet technology based on cleaner production has higher feasibility, and flexibility compared with the dry processing mainly deal with fluctuation of world coffee prices. Development of smallholder Robusta coffee can be performed based on the structures of needs, constraints, required changes, goals, and indicators obtained through the ISM simulation.
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Judul: An Eco-industrial Park Design Using Industrial Symbiosis Approach for Optimization of Value Creation in Coffee Agroindustry
Abstrak: The coffee agroindustry in Indonesia plays a significant economic role as the third largest coffee producer worldwide. Despite the high economic contribution, the coffee agroindustry also raises environmental issues along its supply chain. Coffee solid waste constitutes biomass containing useful compounds promising as raw materials for added-value products through the implementation of industrial symbiosis. Eco-industrial parks create value through industrial symbiosis, emphasizing the principle of a closed-loop production system, simultaneously decreasing the use of raw materials and waste. This study aimed to analyze and develop a coffee-based eco-industrial park design via a systems engineering approach and optimization of industrial symbiosis in closed-loop coffee production. This study employed a case study in the Ketakasi coffee-producing center in Jember, Indonesia. Data collection was conducted through field observation and a series of in-depth interviews. The development of eco-industrial park design used model-based system engineering method, as demonstrated through functional, logical, and physical architectures. Subsequently, the optimization of industrial symbiosis within eco-industrial parks was realized using a mixed-integer linear programming mathematical model. The eco-industrial park design presents the actors, internal business processes, material and data exchanges, various actors’ interdependence and critical roles in material exchanges, and value creation processes using valorization within the eco-industrial park. The role of the Ketakasi cooperative as a facilitator of material exchange and manager of the eco-industrial park is pivotal. The utilization of data integration enhances the transparency and efficiency of information exchange among eco-industrial park participants, promoting predictability and reliability in material exchange. The application of the mixed-integer linear programming optimization model has provided a structured approach to maximizing the value creation within the eco-industrial park through the valorization of 72.3 percent of coffee pulp and 68.5 percent of spent coffee grounds into cellulase enzymes and ultraviolet shields. This study presents a structured framework for efficiently managing material exchange processes within an eco-industrial park, contributing to environmental sustainability and economic value creation. This study contributes to the knowledge gap in the literature by developing an inclusive eco-industrial park design that facilitates the optimization of the value creation process through valorization technology. This study also adds to sustainable agriculture management literature through a coffee-based ecoindustrial park design.
Keyword: Circular economy, Closed-loop production, Coffee agroindustry, Eco-industrial park, Sustainable production, Model-based systems engineering

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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