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Determinantes da adoção de práticas e tecnologias de agricultura de precisão por fornecedores de cana-de-açúcar no estado de São Paulo
(Universidade Federal de São Carlos, 2021-06-10) Mozambani, Carlos Ivan; Vinholis, Marcela de Mello Brandão; https://lattes.cnpq.br/5730999136286305; Souza Filho, Hildo Meirelles de; https://lattes.cnpq.br/3740950346967524; https://lattes.cnpq.br/1411301521327027
The following thesis identifies and analyzes the determinants of the adoption and the intensity of adoption of precision agriculture technologies (PATs) by sugarcane suppliers in the state of São Paulo, Brazil, as well as the main barriers to adoption. In person interviews with 131 sugarcane farmers provided cross-sectional farm level data from the 2018/19 crop year. The farmers were interviewed using a semi-structured questionnaire and the primary data were analyzed by means of descriptive statistics, hypothesis test and count data models. Six PATs adopted by the farmers were identified: GNSS and images for rows planning; tractor/harvester with automatic guidance system; georeferenced grids for soil sampling; images (satellite and/or ARP) for mapping pest and yield; variable rate application of fertilizers; and variable rate application of pesticide. The adoption and adoption intensity (dependent variable) were measured as the number of PATs used by farmers. Fifty-three farmers adopted at least one of these technologies, while 78 farmers did not. The results show that the agricultural information provided by the sugarcane mill, the farm size, as well as the perception of increased productivity are factors that positively and significantly influence the farmer’s decision of adoption PATs. The access to technical assistance information, the participation in agricultural events (workshop, farms fair and farm field days), the farmer’s previous experience, the availability of credit and the perception of increased productivity positively impact the decision to adopt a greater number of PATs, that is, the adoption intensity of the PATs. The adopters indicated that they had faced difficulties related to the connectivity in the field, the lack of technical assistance from equipment suppliers, the lack of trained labor and the incompatibility of the communication interface between computer systems of different agricultural equipment as the main barriers to adoption. For the non-adopters, the main barriers for adoption were the high initial investment.
Análise de sobrevivência em marketing, considerando o modelo exponencial com fragilidade compartilhada, na predição de churn
(Universidade Federal de São Carlos, 2021-06-10) Cintra, Ana Carolaine Hipollito; Fogo, José Carlos; https://lattes.cnpq.br/7654071774665744; https://lattes.cnpq.br/7201415299512060
Services companies like telephony, health plans, internet and others, have redirect their marketing strategies in the customers retention. By maintaining a business relationship with their consumers, companies guarantee capital collection, reducing spending on finding new users. The study of the occurrence of churn is important for customer retention because, by knowing the profile of these consumers, companies can identify others who may breach the contract. This work aims to predict the probability of occurrence of churn based on the relationship time between customer and company, considering services characteristics and the profile of the consumer, using survival analisys and regression models. The exponential model was used for lifetimes, considering customers divided into different groups, or categories. A frailty term was considered to describe the common risk shared by individuals within the group. With the shared frailty model, it was possible to estimate the probability of churn, at a given time, for the group as a whole, as well as for each of the individuals in the group. The shared frailty model was applied to a database of a phone company, whose analyzes were carried out with two clusters: type of subscription and education level of the customers. With the frailty model estimated for the clusters, it was possible to satisfactorily rank the risk of the groups.
Modelos lineares generalizados multinomiais univariado e bivariado
(Universidade Federal de São Carlos, 2021-06-10) David, Leticia Caroline da Silva; Rojas, Francisco Antonio Rojas; https://lattes.cnpq.br/5995701672086579; https://lattes.cnpq.br/2788192007320191
This work presents the basical theorics fundaments of the generalized linear models e the caracteristiscs of the univariate multinomial and binomial logistic regression analysis. Practical aplications of binomial regression and of multinomial were perfomed. The aplication were related the evaluation of effectiveness of an herbicide for the control of a certain weed; of the effectiveness of the radiation level for the house flies control; and for the evaluation of the degree of retinopathy as a function of the individuals' diabetes and other condition. The code of the implementation of the analitycals procedures, run by the softwares R, MATLAB e SAS are avaliable. Also are descrited three bivariate multinomial logistic reggression models: fixed effects conditional, margimal and mixed effects. Applications for each models are presented. The applications are about: the degree of retinopathy avaliation in both eyes of patientsas a function of diabetics and other individual features; the severity of rheumatoid arthritis as a function of the patients status. The code of the implementation of the analitycals procedures, run by the softwares R, MATLAB e SAS are avaliable.
Efeitos fíler e pozolânico do pó de vidro em argamassas
(Universidade Federal de São Carlos, 2021-06-10) Borges, Alexandre Lopes; Ferreira, Fernanda Giannotti da Silva; https://lattes.cnpq.br/0329487394818763; https://lattes.cnpq.br/3641564039262539
The activity of the cement industry results in a huge amount of CO2 emissions mainly due to the calcination of limestone. In this context, numerous researches have been approaching additions in cementitious composites to replace cement amounts in the production of mortars and concretes. It is worth noting that these additions usually come from waste from other industries, thus, in addition to reducing the amount of discarded materials, it reduces the damage caused by the inappropriate destination of this waste. However, for these replacements to be considered viable, several factors must be analyzed, seeking to know the material and its behavior given the new utility. Studies on the use of finely ground glass as a partial substitute for cement have been developed, mainly due to the verification of its good performance as a pozzolanic material with particles smaller than 300 µm. In addition to this pozzolanicity, a physical filling action by the fine grains of the material (filler effect) has been observed, which results in the improvement of the modified cementitious composite. But few studies are deepening the individual contribution of glass powder in cementitious composites due to its physical and chemical effects. Thus, this research aimed to quantify the development of mechanical properties of mortars caused by filling and the pozzolanic effect of the glass powder separately. For this, initially sought to characterize the glass powder and determine its pozzolanic activity and compare the results with those found in the literature for other additions and technical standards. Mortars were developed with different levels of volumetric replacement (0%, 10%, 20%, 30%, and 50%) of cement by finely ground glass passing through the mesh #200 (75 µm), seeking to evaluate the incorporation of glass powder in the physical and mechanical properties of mortars. To differentiate the filler effect from the pozzolanic one, limestone filler was used, whose particle size distribution is similar to the studied glass powder. Mortar characterization tests were carried out on the properties of axial compressive strength, water absorption by capillary, tensile strength by diametrical compression, and static modulus of elasticity for mortars with cement contents replaced by glass and limestone filler in the same amount. The results of the pozzolanic activity of the glass powder indicated reactivity by the Modified Chapelle and electrical conductivity tests, in addition to the chemical composition with the sum of SiO2, Al2O3, and Fe2O3 oxides greater than 70%, and amorphous predominance by XRD. The mechanical results obtained were favorable to the cement replacement content by glass powder in 20% and it was possible to verify that in all the analyzed properties there was the presence of the two effects (filler and pozzolanic) of the finely ground glass in the mortars. The slower chemical activity of the glass powder was observed in relation to cement, with 24% gain in compressive strength due to pozzolanic effect concerning the reference value at the most advanced age of the study (91 days).
O empresariamento da Educação: breve análise sobre a atuação do Instituto Votorantim na educação pública
(Universidade Federal de São Carlos, 2021-06-10) Paes, Denise Araujo; Coutinho, Luciana Cristina Salvatti; https://lattes.cnpq.br/2688318704089723; https://lattes.cnpq.br/3052218981136166
The present work aims to make a brief introductory analysis about the work of Votorantim Institute in Education in the context of educational reforms developed in Brazil since 1990s. There is an increasingly frequent presence of foundations and business institutes offering education projects aimed at public education. The main goal was to analyze the performance of Votorantim Institute in public schools by analyzing the documents published on institute’s website and also by analyzing theses, dissertations and articles. The analyzes were mainly based on the following authors: Melo (2003), Neves (2005), Luz (2009), Peroni (2013) e Freitas (2014). It was observed the impact that business can make at public educations through alliances made between public and private. In the general survey on the role of education in Brazil, the public and private sectors and the growing business performance in the public school, it can understand about the importance of Brazilian public school, to go against or in favor of this current dominant hegemony.
Compósitos à base de quitosana e fibras de celulose como um potencial sistema para liberação controlada de fertilizantes
(Universidade Federal de São Carlos, 2021-06-10) Contieri, Gabriela Aparecida; Messa, Lucas Luiz; https://lattes.cnpq.br/9576740065848780; Faez, Roselena; https://lattes.cnpq.br/0654750186618555; https://lattes.cnpq.br/2797125089099424
Chemical fertilizers are essential to the agrochemical industry when added to the soil to provide the nutrients needed for plant growth. As a more sustainable alternative, innovative and intelligent products are being developed, controlled-release fertilizers. This product offers an extended-release of nutrients to the plant in small amounts. The introduction of these materials in agriculture makes it possible to alleviate water contamination in rivers, groundwater, and the environment. This work aimed to improve the efficiency of using chemical fertilizers with the development of a composite prepared from chitosan and sugarcane bagasse fibers. Biodegradable polymers such as chitosan and cellulosic fibers have been explored to develop “green” composite materials with properties of great technological interest, such as prolonged nutrient release capacity. Chitosan is insoluble in water, making its use as a coating matrix viable, acting as a hydrophobic barrier that will reduce the availability of nutrients to the environment. Cellulosic fibers, in turn, act as a biosorbent medium for nutrients, helping to delay their release. Additionally, the sorbed fibers were characterized by morphological techniques (Scanning Electron Microscopy (SEM), structural (Infrared Region Spectroscopy (FTIR), X-ray diffraction (DRX), and thermal (TGA) methods. It has the potential to be a controlled-release fertilizer due to its promising sorption results. Moreover, concerned with the current educational scenario, new didactic proposals are needed to ensure quality teaching; the Interdisciplinary Island of Rationality proposes a teaching emancipatory and makes the students the protagonist of their education. More current themes can be worked on, such as the insertion of biopolymers in organic chemistry teaching.