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Detecção de câncer de próstata em imagens de microscopia utilizando grafos de contexto glandular
(Universidade Federal de São Carlos, 2021-04-19) Mendes, Rodrigo de Paula; Comin, Cesar Henrique; https://lattes.cnpq.br/9563440403120931; https://lattes.cnpq.br/0502007001258822
Every year a large part of the male population is affected by Prostate Cancer (PCa), with many cases of deaths occurring especially in men over 40 years old. PCa is a pervasive condition that diffuses and manifests itself in a wide range of histological patterns, which can be visualized with details in histological images acquire through biopsy or prostatectomy. Early detection of PCa can improve the prognosis and reduce the risk of death. Currently, the main methodology for the diagnosis of PCa consists of a qualitative analysis carried out by specialists to define the degree of the disease in the so-called Gleason Grading System(GGS), originally defined by Donald Gleason and refined by the International Society of Urological Pathology. Given the importance of identifying abnormal prostate tissue (staging) to improve the prognosis, many computerized methodologies have been developed to assist pathologists in a systematic way for the diagnosis. It is often argued that an improved diagnosis of a tissue region can be obtained by considering measures that take into account various properties of the tissue surroundings, henceforth referred as the context of the tissue. Such a context is considered an important biological factor in staging. This work proposes a new methodology that can be used to systematically define contextual features related to prostate glands. The Gland Context Network (GCN) structure is defined, which is a representation of the prostate sample containing information about the spatial relationship between the glands as well as the similarity between their appearance. It is shown that the GCN can be used to establish contextual features at any spatial scale. Therefore, information that is not easily defined from traditional features can be easily extracted using the proposed approach. In addition, it is identified that even basic properties derived from a GCN can lead to state-of-the-art classification performance in relation to PCa. All in all, GCNs can assist in defining the most effective approaches for PCa detection.
Aspectos termodinâmicos e cinéticos do uso de plugues porosos para a remoção de partículas cerâmicas por bolhas inteligentes
(Universidade Federal de São Carlos, 2021-04-19) Falsetti, Luís Otávio Zaparoli; Ferreira Muche, Dereck Nills; https://lattes.cnpq.br/6542991023278848; Pandolfelli, Victor Carlos; https://lattes.cnpq.br/7369376873984839; https://lattes.cnpq.br/3442810621380817
Non-metallic inclusions can spoil the mechanical properties of the steel depending on their composition, geometry, size and distribution. In this context, “inclusion engineering” is a rising area in steelmaking industry which studies the modification and removal of ceramic particles from the molten steel. Among the likely tools to withdraw these inclusions, the generation of bubbles through purging plugs shows the advantage of allowing the high productivity demanded by the continuous casting. This process comprises the generation of bubbles, their expansion throughout the ladle, the capture of the ceramic particle and their transfer to the slag phase. Thus, understanding the fundamentals involved in each step is of great importance to master the bubbling in ladles aiming cleaner steels. The present work studied the current practice of steel cleaning using bubbles, analysing the size limits to the capture of ceramic particles and discussing alternatives to obtain cleaner steels. Besides, the infiltration of liquid metal into the porous structure was analysed to minimize the plug maintenance due to clogged metal. Therefore, computational calculations were carried out based on mathematical models for each step of purging plug practice, and the results were validated by comparison with physical simulations from the literature and the industrial practice.
Development of stable and high-performance polyaniline activated carbon electrodes for capacitive deionization desalination
(Universidade Federal de São Carlos, 2021-04-19) Barcelos, Kamilla Malverdi; Ruotolo, Luís Augusto Martins; https://lattes.cnpq.br/6167735734348703; https://lattes.cnpq.br/4285214258496042
Capacitive deionization (CDI) emerged as a cost-effective alternative for the desalination of brackish water (salt concentration lower than 10 g L−1). Significant progress in electrode materials in terms of salt adsorption capacity (SAC) and charge efficiency (QE) has been performed in the last few years. However, there are still challenging issues concerning the improvements of the adsorption/desorption kinetics and the electrode stability for long-term operation. In this sense, the main goal of this thesis was the development of stable electrodes of polyaniline (PAni)-activated carbons (PAC) for long-term desalination, with optimized electrosorption/desorption kinetics. The comparison between blade-casting (DB) and free-standing (FS) electrodes of p-toluenesulfonate-doped PAC (PAC/PTS) showed the effects of electrode interparticle porosity and thickness on their textural and electrochemical properties and enabled a better understanding of how tuning the preparation technique of the CDI electrodes can improve the desalination performance, especially in terms of adsorption/desorption kinetics. Although the different electrodes perform similarly in terms of gravimetric salt adsorption capacities, FS electrodes outperform the DB electrodes in terms of volumetric salt adsorption capacities. These carbon films were more compact, and a large quantity of electroactive material was available for salt adsorption. Therefore, if the material cost is not a limitation, the maximum amount of salt could be removed using compact CDI cells with FS electrodes. On the other hand, when the electrosorption and desorption kinetics are considered, the DB electrode presented superior performance, mainly due to its higher interparticle porosity that minimizes the distance of ion diffusion from the bulk solution to the inner surface, thus facilitating the access of the ions to the micropores. These results demonstrated that the faster kinetics provided by enhanced mass transfer in thin electrodes with high interparticle porosity can be decisive for the selection of the best electrode in CDI applications, specially aiming for future applications in flow-through CDI cells. Sequentially, different strategies were studied in order to optimize the desalination performance and the long-term operation stability of PAC/PTS electrodes. Additionally, the new sulfate-doped PAni-activated carbon (PAC/S) was proposed to investigate the influence of chemical and textural properties of the electrodes on the desalination stability. Chemical treatments with ethylenediamine and (3-aminopropyl)triethoxysilane were used to change the chemical surface groups and the potentials of zero charge (EPZC) to more negative values of the materials and promote asymmetry between the electrodes. Symmetric and membrane CDI (MCDI) configurations were also investigated for performance comparison. The control of the potential distribution in asymmetric cells was pointed out as an effective strategy to suppress the carbon oxidation reactions responsible for the SAC loss and improve the long-term stability. However, the best performance and long-term stability were achieved using PAC/PTS electrodes in the MCDI configuration. The use of ion-exchange membranes (IEM) had proved to be a feasible method to improve the electrosorption capacity by reducing the effect of co-ion expulsion and inhibit the faradaic reactions by limiting the transport of the electrochemically active species across the IEM. For this cell configuration, a remarkable value of SAC (~32 mg g-1 at 1.2 V), along with 100% of performance retention was observed over 100 cycles. Our findings enable a better understanding of how to mitigate faradaic reactions and improve the long-term stability of PAC electrodes, thus providing promising electrodes for large-scale CDI applications.
Deposição e caracterização de filmes finos do sistema Zn(1-x)CoxO obtidos por spray pirólise para aplicação em sensor de ozônio
(Universidade Federal de São Carlos, 2021-04-19) Onofre Ramirez, Yina Julieth; Silva, Luís Fernando da; https://lattes.cnpq.br/7422167106177474; Godoy, Marcio Peron Franco de; https://lattes.cnpq.br/2609654784637427; https://lattes.cnpq.br/2454048514942066
The current concern about reducing the harmful effects of air pollution on environment and human health requires adequate gas sensors that allow an efficient control and monitoring on a wide range of pollutants. This encourages the research on new materials and on the modulation of features in order to allow the optimization of gas sensing properties of the current devices. Herein we investigate the effect of the cobalt concentration and the annealing, under controlled atmosphere, on the structural, microstructural, surface chemistry, optical, and gas sensing properties of Zn(1-x)CoxO thin films prepared by spray pyrolysis technique. The films were deposited on Si (100) substrates using a acetate route. The X-ray diffraction (XRD) results indicated that the films have the hexagonal wurtzite ZnO phase and that a loss of crystallinity occurs with Co addition. Scanning Electron Microscopy (SEM) micrographs revealed the films surface are porous and formed by grains, whose average size decreases with Co addition. X-ray photoelectron (XPS) and photoluminescence (PL) spectroscopies results of Co-doped thin films confirmed the presence of Co in the oxidation state +2. The XPS measurements also revealed a higher concentration of oxygen vacancy (Vo) for 2.5 mol% Co film and the effect of annealing in reducing the Vo concentration in films. The pure ZnO film exhibits two broad emission bands in the ultraviolet and green energy range, associated with excitonic transitions NBE and defects related to zinc vacancy (VZn)/ interstitial oxygen (Oi), respectively. Incorporation of Co in ZnO matrix leads to an attenuation of NBE band emission and favored defect-band emissions in the red and the blue energy range, which are respectively attributed to the Co2+ ion, and to the interstitial zinc (Zni)-related defect. The annealing of pure ZnO film promoted the formation of Oi-related defect in the red energy range, and VZn-related defect in infrared energy range when carried out on oxygen and nitrogen atmosphere, respectively. For Co-doped films, the annealing increased the concentration of Zni or Oi/VZn-related defects depending on Co concentration and atmosphere. The DC electrical resistance measurements performed to evaluate the ozone gas sensing of Zn(1-x)CoxO films showed an improvement of the ozone sensor response with the reduction of film thickness and with the Co-doping, where the x= 2.5 mol% is the optimal Co concentration. Moreover, cobalt-doped zinc oxide films (ZnCoO) showed selectivity toward ozone gas in a large concentration range (21-696ppb) and then emerging as a promising material for practical application in ozone gas sensing. The conclusions derived from the average grain size, the point defects and the effect of annealing on the gas sensing suggest that the overall improvement of the ozone sensor response could be attributed to the presence of Zni and Vo-related defects, that act as active sites on the films surface favoring the adsorption of oxygen species.
Proposta de um sistema de bicicletas compartilhadas para uma cidade de médio porte
(Universidade Federal de São Carlos, 2021-04-19) Olmos, Camilo Andrés Mora; Guerreiro, Thais de Cassia Martinelli; https://lattes.cnpq.br/2650555786682535; https://lattes.cnpq.br/0570100407106917
The bicycle-shared systems (BSS) in the world have provided many benefits to cities such as improvements in traffic, health, and the environment. The biggest success factor for shared bikes is the location of the stations. This work presents a proposal for a bicycle shared system for a medium-sized city (Araraquara, S.P.), establishing the locations of the stations and evaluating the characteristics of the municipality. Factors such as locations with a high concentration of travel (generating poles for trips), elements of the bus system, current and designed infrastructure for bicycles, points of interest in the city, topographic characteristics, and profile of bicycle users are considered. The proposed methodology uses the modeling of a Geographic Information System (GIS), which allows the determination of certain characteristics based on analyzes specific to geography such as distances, densities, mappings. In parallel, the GIS connects with decision-making models, such as the Analytical Hierarchical Process (AHP) and the Optimization of Multiple Objectives by Radio Analysis (MOORA). Such methods contributed to the construction of maps indicating the areas of high and medium possibility to locate the stations of the system of shared bicycles, from which three alternatives were generated that evaluated characteristics such as number of bicycles, type of system (manual or automatic) and operating cost. Of these alternatives, the most suitable proposes a mixed system, with a lower cost and an average of trips suitable for an appropriate operation. From the development of the work, it was also possible to characterize the participation of elements such as bicycle infrastructure, temperature and slope within the implementation of the shared bicycle system. Finally, with the progress of the work, Araraquara presented itself as a city with an important potential to implement a system of shared bicycles.
Efeito do teor de titânio no endurecimento por precipitação em uma liga à base de Co-Ni e consequências nas propriedades mecânicas
(Universidade Federal de São Carlos, 2021-04-19) Miura, Leonardo Hideki; Jorge Júnior, Alberto Moreira; https://lattes.cnpq.br/6360362248108490; https://orcid.org/0000-0002-8121-9834; https://lattes.cnpq.br/2215712604237709
The alloy subject of this study, designated by the Unified Numbering System, R30035 and internationally known as MP35N®, is a 35 Ni – 33.5 Co – 20.5 Cr – 9.5 Mo alloy with very-high mechanical strength, ductility, and corrosion resistance. Therefore, it is commonly found under extreme conditions in aerospace, medical, motorsport and petrochemical industry components. Due to this wide range of applications, there are different international standards and specifications for the alloy, which define limits on mechanical properties, or specific ranges of chemical composition for the amplification of some particular property, whether mechanical resistance or corrosion. Changes in the chemical composition have greater potential for altering the alloy's further processing. Specifically, the restrictions of the maximum titanium content in 0.1% compared to the usual 1.0%, in some applications, lead to drastic changes in the plastic behavior of the material, and, in its solidification process, observed in this work. To study the effects of this variation on the chemical composition of the alloy, on the mechanical properties, ingots were produced on a pilot scale in a VIM furnace, which were subsequently hot-formed, solubilized and cold-worked. The basic mechanical properties of the materials were evaluated through tensile, hardness and Charpy-V impact tests at room temperature, after aging in the laboratory. The main difference was the material ductility variation associated with the presence of titanium carbides.