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Estratégias de operações e práticas lean-green: um estudo de casos múltiplos em empresas do setor automotivo
(Universidade Federal de São Carlos, 2021-10-21) Queiroz, Geandra Alves; Alves Filho, Alceu Gomes; https://lattes.cnpq.br/7885557554922569; Torkomian, Ana Lúcia Vitale; https://lattes.cnpq.br/2321084184622795; https://lattes.cnpq.br/4170259002446439
The reduction of environmental impacts has increasingly been treated as a factor of competitive advantage by organizations. This reflects directly on the operational strategies of companies, making it necessary to include environmental performance as one of their competitive priorities. The integration of Lean Manufacturing and Green Manufacturing approaches has been pointed out as a key to improving the competitiveness of organizations because it is a way to equate the environmental priority with other competitive priorities. However, there are still no scientific articles that address all the content of operations strategy (competitive priorities and decision areas) when Lean and Green practices are implemented. In this context, the first step of this study consisted in conducting a systematic literature review presenting some of the main relationships between Lean and Green and the content of operations strategy and highlighting the occurrence of synergies or trade-offs between competitive priorities as well as changes in decision areas when Lean and Green practices are implemented. The results of this study pointed out that Lean and Green integration can promote synergies between competitive priorities, but it can also promote trade-offs between some competitive priorities, with the trade-off between cost and environment priorities being the most frequently mentioned. Furthermore, Lean is pointed out as a basis for the management of production systems, and green practices are generally used as a complement and to support the inclusion of the environment as a competitive priority. The second stage of this research was to conduct case studies in six companies in the automotive sector that implement Lean and Green practices, with the purpose of identifying the contents of their operations strategies. The results indicated that the companies attribute different levels of importance to the priority environment and have different levels of Lean and Green. In general, the companies consider that the Lean-Green approach generates synergies between priorities, with the trade-off between cost and environment being the only one addressed in the cases. It was confirmed that Lean can contribute to the reduction of environmental impacts reduction, especially regarding to resource consumption. Moreover, it was found that the companies that prioritize the environment more in their actions presented more changes in the decision areas. The crossing of the theoretical results with the empirical results allowed us to reinforce the theoretical propositions stated in this thesis. All the propositions formulated from the systematic literature review were illustrated in the cases studied and complemented with some questions.
Análise numérica de barras compostas em perfis de aço formados a frio submetidas à compressão
(Universidade Federal de São Carlos, 2021-10-21) Nunes, Riterson Jacques; Maia, Wanderson Fernando; https://lattes.cnpq.br/5473998179826262; Nardin, Silvana de; https://lattes.cnpq.br/5587716781980132; https://lattes.cnpq.br/5697490362140240
Built-up columns are an interesting alternative when isolated channels do not comply with structural performance requirements. During their lifespan, one of the most common stresses in built-up columns is the compression. Usually, built-up columns are formed by two channels spaced apart, examples being doubled U “back-to-back” or “front to front”. The various possibilities of bracing change the structural behavior to the shear, thus make it difficult to predict the normal resistance force of compression. The American Standard ANSI/AISI S100 (2020) presents an adaptation of the global slenderness for built-up columns, but only considers profiles in contact. Eurocode 3 (2006) distinguishes in elastic analysis, battened and laced built-up columns, but without a specific calculation method for cold-formed profiles. In this context, this work has as main objective to analyze the axial compression resistant capacity of built-up columns in double U section “back-to-back”. Numerical analyzes were carried out in the Ansys software to evaluate the influence of the following geometric parameters on structural behavior: types of bracing, number of battened plates, length of the built-up columns, spacing between channels and thickness of the channels. For each of the models, the normal compressive strength and instability modes were evaluated. In addition, the applicability of normative procedures to predict the resistive force was also evaluated. The results showed that longer built-up columns presented greater increase in the normal resistance force when compared to insulated channels. The increase in the number of battened plates did not show linear variation of the normal resistant force. For battened built-up columns, in most cases analyzed, Eurocode 3 (2006) presented lower resistance values than ANSI/AISI S100 (2020). Lot laced built-up columns Eurocode 3 (2006) underestimated the numerical results for greater thickness. The type of bracing had a greater influence on the models with higher overall slenderness, that is, for greater lengths and closer channels.
Produção de coquetel enzimático rico em endoglucanase termoestável em biorreator de leito empacotado e sua aplicação na obtenção de nanocelulose
(Universidade Federal de São Carlos, 2021-10-21) Katayama, Eric Takashi; Casciatori, Fernanda Perpétua; https://lattes.cnpq.br/1269950652196294; Farinas, Cristiane Sanchez; https://lattes.cnpq.br/9933650905615452; https://lattes.cnpq.br/6107424631716712
Nanocellulose is a bioproduct with high added value obtained through the conversion of lignocellulosic biomass. Due to characteristics such as high aspect ratio, low toxicity, thermal stability and high crystallinity, nanocellulose has several applications. Obtaining nanocellulose through the enzymatic route stands out for being an environmentally friendly method, however studies are necessary to improve the efficiency of this process. In this sense, the use of an enzymatic cocktail with thermostable properties can be an interesting strategy for obtaining nanocellulose. In this work, the objective was to use the packaged bed bioreactor for the production of thermostable enzymatic cocktail and apply the enzymes to obtain nanocellulose. To obtain this cocktail, the thermophilic fungus M. thermophila was cultivated by fermentation in solid state on a small scale using full factorial design varying the bagasse mass, soybean meal fraction and moisture. The selected cultivation conditions were replicated in a multilayer-packaged bed bioreactor. The enzymes were then used to hydrolyze cellulose pulp at temperatures of 50, 60 and 70 °C and convert the substrate into nanocellulose. The enzymatic extracts of the fungus M. thermophila obtained both on a small scale and in bioreactor showed the activities of endoglucanase around 200 U/g-substrate. The hydrolysis of the pulp performed at 60 °C showed better results, converting 60% of the cellulose, with yield of 16.2% of nanocellulose with 96 hours of hydrolysis. The nanomaterials obtained presented crystalline index of 77.4%. By FTIR it was possible to verify that the chemical compositions of the nanomaterials obtained were nanocellulose. On set temperatures were 152 to 194 °C. Atomic force microscopy showed that the obtained nanocrystals had an average length of 157 nm and an aspect ratio ranging from 1.1 to 10.0. Although the yield of nanocellulose is still lower when compared to that of acid hydrolysis, advances in enzymatic hydrolysis can still be obtained, investigating other possible enzymes that degrade lignocellulosic biomass, such as oxidative enzymes.
Optimization models and solution methods for the vehicle allocation problem
(Universidade Federal de São Carlos, 2021-10-21) Cruz, Cesar Dario Alvarez; Munari Junior, Pedro Augusto; https://lattes.cnpq.br/1328868140869976; Morabito Neto, Reinaldo; https://lattes.cnpq.br/4194801952934254; https://lattes.cnpq.br/4498316314606067
The Vehicle Allocation Problem (VAP) consists in allocating a fleet of vehicles to attend the expected demand for road freight transportation between terminals along a finite multiperiod planning horizon. The objective is to maximize the profits generated for the completed services. Previous deterministic and stochastic approaches used heuristic procedures and approximation methods for solving large scale instances of this problem. This thesis contributes with models and solution methods for solving effectively large-scale instances of the VAP. The first method is Branch-and-Benders-Cut (BBC) for solving the space-time network formulation of the VAP. The Benders reformulation results in each subproblem being a multiple origin-destination minimum cost flow problem among empty vehicles exclusively. We propose two valid inequalities in order to reduce the number of infeasible cuts needed to reach a feasible and optimal solution. In addition, we use network flow algorithms in trying to accelerate the process of cut generation. Computational results are shown for randomly generated instances. The second method is a tailored exact Branch-and-Price (BP) procedure, that provides optimal solutions or certificates of quality, for solving large-scale problems within reasonable computational times. This method is the result of reformulating a compact Integer Linear Programming model of the VAP through the Dantzig-Wolfe (DW) decomposition and using efficient procedures for solving each component of the reformulation. The Primal Dual Column Generation Method (PDCGM) is used to solve the master problem, while the subproblem is modeled as a Maximum Cost Flow Problem and solved using the aggregation of optimal longest paths problems on Directed Acyclic Graphs (DAG). Finally, we resort to three branching procedures to obtain the optimal integer solution of the VAP. Computational experiments with instances from a case study and random realistic-sized instances are presented and analyzed, showing that the method has a superior performance with respect to other exact approaches in solving large-scale VAP instances. The third method is based on preprocessing the time-space extended graph and reformulating the problem in terms of routing empty vehicles along demand nodes. The resulting model's size depends on the number of demand nodes (arcs in the previous model) and fleet size, which can be advantageous when the number of terminal-period pairs in the time-space extended network is large compared to the actual number of loads requested. We propose a BP method based on the DW reformulation of this new modelling approach. The results of both, the reformulation solved by CPLEX and the BP, shows the superior performance of this new approach in solving realistic-sized instances of the VAP.
Idosos que cuidam de outros idosos: um estudo sobre sobrecarga e fragilidade
(Universidade Federal de São Carlos, 2021-10-21) Macedo, Marcela Naiara Graciani Fumagale; Santos-Orlandi, Ariene Angelini dos; https://lattes.cnpq.br/1334146454214813; https://lattes.cnpq.br/4508304026036940
In the national context, the family is the primary source of support for the older adult. As a result of population aging and the diversity of family arrangements, the number of older people caregivers of other dependent older adults increases. The task of caring may arise suddenly, without prior instruction or support from third parties, resulting in intense burden, especially for older adult caregivers. Scholars claim that this psychological tension can culminate in the development of frailty. Both burden and frailty can impact the quality of life of those involved and interfere in the quality of care offered, especially in contexts of high social vulnerability. With the early identification of both conditions, interventions can be thought out in order to reduce spending on health services and improve the quality of life of these individuals. Objective: analyze the relationship between burden and frailty of older adults who take care of others older adults registered in Family Health Units (FHU) with a high social vulnerability context. Method: a cross-sectional, quantitative study conducted in a municipality in the interior of São Paulo. This is a larger study, in which 65 older adults aged 60 years or older, registered in FHUs and caring for the older adults participated. Data were collected at the household of the older adult caregiver, from July 2019 to March 2020, by previously trained researchers. The following instruments were used for data collection: questionnaire to characterize the older adult caregiver and the context of care, the Zarit Burden Scale, and the frailty phenotype proposed by Fried. Descriptive and correlational analyses were performed. The differences between the groups were estimated using Pearson’s Chi-square, Fisher’s Exact and Mann-Whitney tests. The significance level adopted was 5% (p<0,05). Results: there was a predominance of older adults female caregivers (56.9%), aged 60 to 74 years (78.5%) and with a partner (93.9%). The majority of interviews were spouse caregivers (89.2%), had no prior training (96.9%) and no support to perform the task of caring (58.5%). There was statistical significance between high levels of burden and frailty (p=0.004). Frailty presented a statistical relationship with marital status (p=0.016), depressive symptoms (p=0.029), cognitive decline (p=0.029), and degree of kinship with the older adult care (p=0.015). Conclusion: there was a relationship between high burden and frailty in the older adults who care for other older adults seen in Family Health Units in a context of high social vulnerability. Most of the older adults who scored for absent or moderate burden were not frail, while older people caregivers who scored for moderate to severe or severe burden were frail.