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Análise dos serviços emergenciais de manutenção agrícola e borracharia na agroindústria canavieira utilizando teoria de filas
(Universidade Federal de São Carlos, 2014-10-03) Rodrigues, Lásara Fabrícia; Morabito Neto, Reinaldo; https://lattes.cnpq.br/8208188426851836
The sugarcane industry is an important branch of the Brazilian agroindustry considering the major role of sugarcane cultivation in the country history and the prominent position that this industry has achieved in the international scenario. In recent years, this industry has faced major changes and challenges. Therefore, the use of methods to support decision making has become increasingly necessary to optimize the available resources and enable the analysis of larger data sets. The present study addresses the Maintenance and Tire Repair Emergency Services in the agricultural stage of the sugarcane industry. In order to analyze and support decisions in the Tire Repair System, the Hypercube Model, the Simulation Model, and the known Queue Models M/M/m and M/G/m were developed or adapted using data from a case study conducted in a sugar and alcohol mill with centralized servers. In addition, an alternative scenario with decentralized servers was also investigated, and it showed better results in terms of performance measures compared to those of the original scenario. Extensions of the Hypercube Model, the Approximated Hypercube Model and the Simulation Models were developed to analyze and support decisions in the Maintenance Service System. At first, an illustrative example was used to address the issues of priority queue, partial backup, and differentiated service rates between the hypercube states and the states of the tail. Subsequently, experiments using these models and the case study data were conducted. An alternative scenario including one more server was also studied, and it showed better results than those of the original scenario, especially in terms of travel times. The present study shows that the adaptations and extensions of the hypercube model and the simulation models developed to treat Maintenance and Tire Repair Emergency Systems in sugarcane mills have proven to be effective approaches for these systems planning and analysis. The results of this study indicate that the models developed and adapted are suitable for application in sugarcane industries.
Contribuição ao estudo e modelagem matemática de reator anaeróbio de leito granular expandido (EGSB) tratando água residuária de suinocultura
(Universidade Federal de São Carlos, 2014-10-03) Correia, Gleyce Teixeira; Kwong, Wu Hong; https://lattes.cnpq.br/8644937548157443
Anaerobic systems have been widely studied and used in treatment of wastewater from agriculture and others. Among the existing technologies, there are the EGSB (Expanded Granular Sludge Bed) reactors, which have emerged as improvement of UASB (Upflow Anaerobic Sludge Blanket) reactors. It was sought to evaluate the performance of an EGSB reactor using synthetic swine wastewater as substrate, increasing the volumetric organic load (2, 4, 8, 10 and 15 kgCOD.m-3.d-1) and the upflow velocity (6 and 10 m.h-1). Efficiencies higher than 83% were obtained in removal of COD, however there was a buildup of volatile acids and a possible microbial imbalance after the application of the load 10 kgDQO.m-3.d-1. The reactor showed homogeneity in microorganisms along the reactor, with the presence of bacilli of different sizes, coccus, and similar to the genera Methanosaeta and Methanosarcina. It was developed a mathematical model aiming to study in more detail the hydrodynamics of EGSB, generally regarded as continuous complete mix reactors (CSTR). For that, it was used a phenomenological model based on the mass balance of the reactor, and after the adjustment to the experimental data, it was observed that the EGSB reactor can be worked as a series of five continuous complete mix reactors (CSTR), three in the tube region and two in the separator region with kinetic intrinsic rate at approximately 7,5.10-5 L.mgSSV-1.h-1 and kinetic rate constant decreasing with increase in organic load.