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Development of filter media from cellulose acetate polymer containing silver nitrate (AgNO3)
(Universidade Federal de São Carlos, 2024-04-30) Zamanikia, Ali; Chagas, Paulo Augusto Marques; Aguiar, Mônica Lopes; https://lattes.cnpq.br/0431688649128529; https://lattes.cnpq.br/5058306486487284
This master's thesis provides a thorough analysis of the creation of nanofiber media with enhanced antibacterial characteristics that are integrated with cellulose acetate polymer and silver nitrate (AgNO3). The study focuses on the synthesis and characterization of electrospun nanofibers, employing a range of analytical techniques, including Fourier Transform Infrared Spectroscopy (FT-IR), filter efficiency, and filter permeability. The primary objective of this research is to understand the influence of varying silver nitrate concentrations (3%, 5%, and 10%) on the properties of cellulose acetate nanofibers. Scanning Electron Microscopy (SEM) analysis reveals that the nanofiber diameter is affected by the addition of silver nitrate, with preliminary findings indicating that higher concentrations result in decreased nanofiber diameter compared to lower concentrations or pure cellulose acetate nanofibers. This observation suggests the potential for tuning nanofiber properties to achieve specific filtration and antibacterial performance. Furthermore, the study investigates the chemical composition and bonding modifications within the cellulose acetate nanofibers. FT-IR spectroscopy reveals spectral changes associated with the incorporation of silver nitrate at different concentrations, indicating possible modifications in chemical composition and bonding. These modifications are suggestive of interactions between silver nitrate and the cellulose acetate polymer, which alter the molecular structure and functional groups within the nanofibers. Also, the permeability and efficiency results provide valuable insights into the impact of silver nitrate concentration on the filter's performance. The findings of this research offer valuable insights into the development of filter media with tailored antibacterial properties, highlighting the potential for optimizing nanofiber diameter and chemical composition through the controlled addition of silver nitrate.
Trançando vidas: entre frestas e tessituras de cuidado para a sustentabilidade da vida
(Universidade Federal de São Carlos, 2024-04-30) Santos, Tainá Souza; Vianna, Anna Catarina Morawska; https://lattes.cnpq.br/2245801371286766; https://lattes.cnpq.br/7652206946442553
This research aims to highlight the experiences and alliances between black and peripheral women linked to a Civil Society Organization (CSO) located in the city of São Carlos - SP. The CSO Casa da Infância Estrela da Manhã is an institution that offers projects and assistance to families, children and young people in a context of social vulnerability in the Antenor Garcia neighborhood. Among the projects offered by the institution is Trançando Vidas, which welcomes women from the community with the aim of preventing domestic violence, promoting financial autonomy, strengthening bonds and meeting family demands through social assistance services. Based on ethnographic research in Estrela da Manhã, , the purpose of this work is to describe the production of care among women for the sustainability of personal and family life, drawing on theoretical references from black and decolonial feminism, as well as to point to the recent discussions at national level about care work for the elaboration of the National Care Plan and Policy.
O uso de chatbots para auxiliar a recuperação da informação em repositórios institucionais
(Universidade Federal de São Carlos, 2024-04-30) Marques, Samara Sivirino; Nhacuongue, Januário Albino; https://lattes.cnpq.br/0372192175262438; https://orcid.org/0000-0002-6679-1306; https://lattes.cnpq.br/3484634265893214; https://orcid.org/0000-0002-1768-3114
The study aims to analyze, based on national and international literature, how NLP and chatbots can contribute to the retrieval of information in institutional repositories. Three specific objectives were established: identify and map the main problems in research on NLP and chatbots in the area of information retrieval; analyze the solutions proposed in each study, highlighting approaches to improve information retrieval; characterize the specific applications of each study in order to improve information retrieval in institutional repositories, highlighting the practical contributions and potential benefits to the information search and retrieval process. The research adopts the content analysis methodology. Thematic categorical analysis was used to analyze the results obtained, providing a deeper understanding of the trends and patterns identified. The analysis categories were established based on the four-dimensional space in which the concept of relevance can be formally defined, for the purposes of evaluating information retrieval systems. Therefore, the research was based on two categories: information resources and representation of the user's problem. The research analyzes 263 articles published between 2019 and 2023, selected through the Web of Science database. The results highlight the importance of using NLP and chatbots in optimizing information retrieval in institutional repositories. These technologies have the potential to transform the way users interact and access information, providing a more efficient, personalized and accessible search. From the results, it can be inferred that a task-driven repository and the construction of chatbots based on existing, intuitive and open source tools is a way of applying the research analyzed. It is concluded that there is a promising scenario in the use of NLP and chatbots to improve information retrieval in institutional repositories, simplifying the research process and making it more efficient for users. For future research, there are opportunities to explore advanced NLP techniques to improve chatbots' understanding of complex queries and personalize the user experience by adapting the interaction style and providing relevant content recommendations.
Fatores do teletrabalho e gênero: uma análise integrada sobre as percepções das servidoras TAEs de uma universidade pública federal
(Universidade Federal de São Carlos, 2024-04-30) Elias, Solange Rachel; Ubeda, Cristina Lourenço; https://lattes.cnpq.br/6696784421924024; https://orcid.org/0000-0001-6460-9462; https://lattes.cnpq.br/6141077722316946; https://orcid.org/0009-0006-3814-0465
This research's main objective is to discuss the perceptions of technical-administrative education employees (TAEs) at a federal public university on the factors of teleworking. The term teleworking is quite broad in the literature, being associated with work carried out remotely, through Information and Communication Technology (ICT). Adherence to this type of work had been growing gradually, both in private companies and public institutions, however, the global COVID-19 pandemic accelerated and intensified this process. Studies indicate that these changes hit women more intensely, causing a workload due to the need to deal with personal activities, domestic tasks, parental care, in addition to the high demand for paid work, reinforcing the gender expectations attributed to them. In order to better understand this scenario, a combined approach was carried out, using the survey research method. Data were collected through a semi-structured questionnaire prepared with open and closed questions, measured using the Likert scale, and sent electronically to the TAEs of the four campuses of the researched university in order to obtain a more reliable and comprehensive overview. the proposed situation. 153 responses were obtained from TAE servers, with a return rate of 48.73%. Quantitative data analysis was performed using descriptive statistical analysis, correlation analysis (CA) and exploratory factor analysis (EFA) using IBM SPSS Statistics software, while qualitative data was analyzed using content analysis. According to the results obtained, the correlation analysis (CA) between the variables confirmed the positive relationship with practical significance and the exploratory factor analysis (EFA) defined three factors related to teleworking that cover the interconnections between professional and personal life/ family and the interrelationships between the employee and the workplace. Finally, it appears that there was broad agreement in the participants' responses in practically all variables, configuring teleworking as something positive and confirming the three hypotheses proposed in this research, in order to show that there is a positive relationship between teleworking and professional practice (H1), professional integration (H2) and mediations between personal life and professional life (H3). Given the results, it is concluded that teleworking brings positive effects on both aspects of professional and personal life, given that the possibility of organizing and managing your professional tasks with greater autonomy and flexibility, allows for conciliation and balance with other personal activities, bringing greater satisfaction, productivity and motivation to these TAEs, however, this conciliation between so many different demands can hide an inequality in the sexual division of work, especially in aspects of personal life
Potencial dos compostos orgânicos voláteis como estimulantes vegetais: uma investigação em diferentes cultivares de tomate
(Universidade Federal de São Carlos, 2024-04-30) Aguiar, Maria Clara Santana; Forim, Moacir Rossi; https://lattes.cnpq.br/1234565160573730; https://orcid.org/0000-0001-8798-2921; https://lattes.cnpq.br/0503514392141729; https://orcid.org/0000-0001-5357-0355
Essential oils extracted from plants are composed of volatile organic compounds that have a wide range of biological activities in vital systems. Various effects of essential oils on plant growth have been demonstrated. However, their effects at the molecular level are not well understood. In addition, their volatile and degradable nature limits their application. Therefore, we investigated the potential of rosemary (Rosmarinus officinalis), lemon balm (Lippia alba), and orange (Citrus sinensis) essential oils as plant biostimulants using the tomato cultivars Solanum pimpinellifolium and S. lycopersicum as models, classified as Plant Introduction (PI) and commercial, respectively. To evaluate the biostimulant activity of essential oils, this study was conducted in three research fronts, namely (i) the development of the formulation containing the biostimulant, (ii) the evaluation of extraction methods to characterize biotic interactions, and (iii) the application of the formulated products in tomato cultivars. The first stage of the research was to improve the dispersion of essential oils in an aqueous medium. Therefore, a method for obtaining biopolymer microcapsules containing essential oils was evaluated. To prepare the microcapsules, we evaluated the type of biopolymer (native and modified manioc starch), the surfactant content (polysorbate 80) and the addition (or not) of adjuvants (banana, pequi and lignin residues). The emulsions were analyzed for their viscosities, surface morphologies, and oil concentrations after emulsion preparation and soil application. We found that the use of modified starch combined with the addition of adjuvants favored the microencapsulation process with essential oil recoveries higher than 85% (v v-1). In the soil tests, we observed that the biopolymer microcapsules allowed the retention of oils twice as high as the emulsified oils. For the second phase of this study, we investigated the extraction techniques of plant samples for instrumental metabolomic analysis. This process was essential to ensure standardization and reproducibility of plant material analyses. Using the methods evaluated, we observed that for both cultivars there was a gradual modulation of gibberellins and furanocoumarin precursors during the developmental stages. In addition, commercial plants showed a higher accumulation of isoflavones in the vegetative stage, which may be related to the purple color of their leaves. The PI during development showed a greater induction in the biosynthesis of glycosylated molecules of quercetin and kaempferol. The PI variety was also the only one in which we detected the beta-tomatine molecule in the developmental stages. In the third step, we applied the formulations containing the essential oils and verified, using standardized methods, the induction in the biosynthesis of metabolites related to defense mechanisms for both cultivars after the treatments. In addition, we confirmed that the essential oils stimulated root growth, confirming their biostimulant potential for tomato plants. These data represent the first step in the development of products containing essential oils as plant biostimulants.
Estudo de elementos finitos para obtenção de valor de esforços nas uniões montadas por conformação em gabinetes de lavadoras de roupa
(Universidade Federal de São Carlos, 2024-04-30) Silva, Andrew Rivail Finamore da; Moreno, Mariano Eduardo; https://lattes.cnpq.br/1307496862518321; https://lattes.cnpq.br/5264989202273201
White goods companies aim to achieve customer loyalty by implementing the most suitable and practical methods while applying processes for increased productivity and cost efficiency to generate satisfactory profit margins with quality products. In this context, a well-established process in industries is addressed: the joining of metal sheets through clinching. This is a recent process applied nationally in the assembly lines of automobiles, computers, and household appliances, involving localized cold forming of sheets to reduce costs and enhance productivity. This work focuses on the application of clinching in the manufacturing of washing machine cabinets, proposing a study of the forces present in the joined areas during machine operation using the Finite Element Method (FEM) to obtain values of forces at the joining points. The main objective was to quantify the physical forces in the washing machine cabinet joints through FEM simulations, such as Siemens NX or Ansys, as well as to formulate the main parameters that these forces generate based on experiments and directions of stresses and critical frequencies that disturb the connections. The results were divided into the following categories: acquisition of critical load data from modeling Clinch points in FEM; analysis of forces in the joints through modeling of the washing machine cabinet structure using FEM; comparison of permissible and applied forces, obtaining safety coefficients and thus validating the evaluated models.
Otimização do roteamento de aeronaves com emparelhamento de tripulações para o transporte aéreo não regular
(Universidade Federal de São Carlos, 2024-04-30) Vieira, Thiago José dos Santos; Morabito Neto, Reinaldo; https://lattes.cnpq.br/4194801952934254; https://orcid.org/0000-0002-3948-305X; Munari, Pedro; https://lattes.cnpq.br/1328868140869976; https://orcid.org/0000-0001-5929-593X; https://lattes.cnpq.br/0853017869854389; https://orcid.org/0000-0001-9186-8769
This dissertation addresses aircraft routing problems with crew pairing in the context of non-scheduled air transportation. These problems involve complex decisions in a highly dynamic and costly environment, where various civil aviation regulations must be followed. There is a lack of operations research literature on non-scheduled air transportation, and this type of service has significant differences from conventional (scheduled) transportation. Overall, this research covers real-world problems of two companies belonging to the sector, categorized in academia as a dial-a-flight problem and an aircraft recovery problem. The first refers to fractional ownership services with private aircraft sharing. In this scenario, the customer owns an equity part of aircraft managed by an airline, which entitles him/her to fly a certain amount of miles during the period. We proposed a detailed optimization model, MIP-based heuristics and an exact branch-and-price algorithm. The second problem refers to a rescheduling (recovery) of flights as a way to mitigate the damage arising from past disruptions (adverse weather conditions, mechanical failures, etc.). Given a flight timetable, we need to determine new departure times, redesign routes, reassign flights to different aircraft, and examine potential flight cancellations. We formulated network-flow, event-based and discrete-time models. Additionally, we developed tailored constructive and improvement heuristics. To verify the adequacy and coherence of the approaches, several experiments were performed with real-life data. In the first problem, all instances were solved optimally, and in the second, we were able to generate effective reschedules without canceling flights, in relatively short computing times.
Relação entre testes autonômicos cardiovasculares, achados ecocardiográficos e marcadores glicêmicos no Diabetes Mellitus tipo 2
(Universidade Federal de São Carlos, 2024-04-30) Sant'Anna, Leticia de Souza; Catai, Aparecida Maria; https://lattes.cnpq.br/5801652590531684; https://orcid.org/0000-0002-4837-3936; https://lattes.cnpq.br/2158323388334674; https://orcid.org/0000-0003-1845-0344
Introduction: Diabetes mellitus is a metabolic disease recognized worldwide as a public health emergency. Chronic hyperglycemia, the main cause of the disease, can lead to vascular and autonomic complications, including cardiovascular autonomic neuropathy (CAN). This complication is directly linked to the duration of the disease and the control of glycemic levels. Cardiovascular autonomic tests are essential to diagnose CAN, through stimuli that alter heart rate and blood pressure. The presence of NAC can affect cardiac function, even leading to heart failure and increasing morbidity and mortality. Echocardiography is a technique used to evaluate cardiac function, allowing the identification of various changes. Patients with type 2 diabetes mellitus (DM2) may present relationships between cardiovascular autonomic tests and glycemic control, highlighting the importance of cardiac monitoring in this group of patients. Objective: To evaluate the relationship between cardiovascular autonomic tests, ventricular function (systolic and diastolic) and markers of glycemic control in individuals with type 2 diabetes mellitus with and without cardiovascular autonomic neuropathy, and, in addition, to analyze the possible influence of glycemic control on these responses. Methods: 62 individuals (36 men and 26 women) with DM2, aged between 40 and 65 years and BMI 29±4, were evaluated, divided into 4 groups: a) without NAC CG (with glycemic control); b) without NAC SCG (without glycemic control); c) NAC CG and d) NAC SCG. The R-R intervals (iRR) of the electrocardiographic signals, obtained from the MC5 derivation, were captured by the BioAMP and the respiratory signals by a respiratory belt. The echocardiographic variables of systolic and diastolic function were evaluated by two-dimensional mode.Blood tests and three cardiovascular autonomic tests were also performed, which evaluated the response of heart rate (HR) and systolic blood pressure (SBP) to postural change stimuli. active (MPA), maneuver to accentuate respiratory sinus arrhythmia - MASR (Expiration/Inspiration), ratio 30:15, and Valsalva maneuver (MV), which also evaluates the contribution of the cardiac parasympathetic nervous system. Results: The main findings were evident positives between E/A ratio and 30:15 (r=0.848), in the NAC CG group, respectively; and negative between HbA1c and left ventricular diastolic diameter in the group without NAC CG (r=-0.727), between MASR and HbA1c in the NAC CG group (r=-0.939) and NAC without CG (r=-0.531). Conclusion: Individuals with CAN obtained lower values in the indices of cardiovascular autonomic tests, with lack of glycemic control being a factor that contributes to worse results. The relationship between the E/A ratio indices and the HR response to postural changes in the group with NAC CG suggests a relationship between echocardiographic findings and responses to autonomic tests, but more studies are needed to be able to define these findings as markers of LV diastolic dysfunction.
Dimensionality reduction-based metric learning using information theoretic measures
(Universidade Federal de São Carlos, 2024-04-30) Cervati Neto, Alaor; Levada, Alexandre Luis Magalhães; https://lattes.cnpq.br/3341441596395463; https://orcid.org/0000-0001-8253-2729; https://lattes.cnpq.br/6840931161315479; https://orcid.org/0000-0001-6212-6205
Processing large amounts of data to extract useful information is one of the main issues that may be approached using machine learning. One way to obtain this information is by grouping data according to their common features. In very complex data sets, this task may be accomplished by finding simpler ways of representing the relations between this data, lowering their dimensionality. There are many methods to find the data groups in a set automatically. However, finding a way to minimise the complexity of this data without losing relevant content is a computationally costly process. An alternative to that is treating these data sets as probability distributions of random variables and using concepts and measures from information theory to find their relations more efficiently. This work describes some dimensionality reduction methods and information theory measures and proposes that they be joined in order to obtain better results, by creating variants more resistant to disruption in data or differences in set sizes. The adaptation of existing methods to include information theory-based measures is tested on real datasets, and results formally verified as to their adequacy for obtaining more accurate metrics. In most of the tested cases, results show a better performance compared to traditional classification methods, while in others the modifications made those more effective for datasets with fewer samples.
Design of multicomponent alloys with single c14 laves phase for hydrogen storage assisted by thermodynamic computational methods
(Universidade Federal de São Carlos, 2024-04-30) Ponsoni, Jéssica Bruna; Zepon, Guilherme; https://lattes.cnpq.br/7924187202036614; https://orcid.org/0000-0002-5852-9076; https://lattes.cnpq.br/4994835560866357; https://orcid.org/0000-0003-0001-6689
Multicomponent alloys with C14 Laves phase structure hold great promise as hydrogen storage materials due to their capacity for reversible absorption of significant hydrogen amounts at room temperature with excellent kinetics. Design methodologies that incorporate predictive property modeling is essential for effectively navigating the vast compositional space of multicomponent alloys. The effectiveness of an alloy as a hydrogen storage media depends on its thermodynamic properties, often visualized through pressure-composition-temperature (PCT) diagrams. Therefore, the prediction of PCT diagrams for multicomponent alloys is a paramount factor to design alloys with optimized properties for hydrogen storage applications. This doctoral thesis introduces a strategy based on computational thermodynamics to design C14-type Laves phase alloys optimized for hydrogen storage. The design method employed to investigate the phase stability of alloys of the (Ti, Zr, or Nb)1(V, Cr, Mn, Fe, Co, Ni, Cu, or Zn)2 system, resulted in 440 alloys prone to solidify as C14 Laves phase structure. A thermodynamic model was developed to calculate the PCT diagrams of the C14 Laves phase alloys. It was possible to design compositions with equilibrium pressures in a wide range (10−4 to 105 bar). Based on this design approach, seven alloys with different equilibrium pressures were selected, produced, and experimentally characterized. Three alloys did not require activation procedures: (Ti0.5Zr0.5)1(Mn0.5Cr0.5)2, (Ti0.5Zr0.5)1(Fe0.33Mn0.33Cr0.33)2, and (Ti0.33Zr0.33Nb0.33)1(Mn0.5Cr0.5)2 alloys, and they reached hydrogen storage capacity close to H/M = 1 with fast kinetics. Moreover, the experimental PCIs were compared to the calculated ones. The order of magnitude of the equilibrium pressure for the tested alloys were well predicted by the model. These three compositions presented outstanding reversible hydrogen storage properties. Furthermore, the addition of a small fraction of Ce (0.4 wt.%) was proved to be an efficient strategy to allow activation of the alloys that were not able to be activated by thermal or hydrogenation treatments. The (Ti0.5Zr0.5)1(Fe0.5Mn0.5)2 + Ce alloy reversibly absorbed and desorbed the total amount of hydrogen (H/M = 0.9) at room temperature with excellent cycling stability.
Avaliação e caracterização química de substratos vegetais para atração e monitoramento de Sphenophorus levis Vaurie, 1978 (Coleoptera: Curculionidae)
(Universidade Federal de São Carlos, 2024-04-30) Lima, Wéllima Timóteo de; Marques, Rodrigo Neves; https://lattes.cnpq.br/8945237946471247; https://orcid.org/0000-0003-1003-3706; Fujihara, Ricardo Toshio; https://lattes.cnpq.br/1863735094370774; https://orcid.org/0000-0003-2776-5559; https://lattes.cnpq.br/8547527969308227
Brazil is the world leader in sugarcane production, a crop of extreme relevance to the agribusiness sector. However, Sphenophorus levis, one of the main pests of this crop, has affected production in some regions of the country. Therefore, it is necessary to improve monitoring and control methods, as the underground habitat of the pest is a limiting factor. The aim of this study was to evaluate whether different plant substrates (sugarcane, sugarcane with 10% molasses, pineapple peel, banana pseudostem, and coconut fiber) and their volatile compounds have attractive potential for S. levis adults. Samples of these plant substrates were subjected to different periods of natural degradation (0, 24, 48, and 72 hours) in a B.O.D. at 26°C, and subsequently processed and stored in a freezer. Next, the pH, total and soluble solids, carbon, and total nitrogen of the samples were characterized, and the organic volatile compounds were identified and quantified by gas chromatography with flame ionization detection (GC-FID). To test the attractiveness of the substrates, assays were performed in choice arenas containing four treatments (plant substrates) and 30 repetitions (15 female and 15 male S. levis adults), with the duration of permanence on the substrate evaluated for 30 minutes. The most frequently occurring volatile compounds in the physicochemical characterization were selected to evaluate their attractiveness to S. levis adults. The results showed variations in pH and total and soluble solids over time for all plant substrates, as well as ethanol and acetic acid contents, the main volatile compounds present in the natural degradation of the substrates. The degree of substrate degradation did not interfere with attractiveness; however, the concentration of volatile compounds influenced insect attraction. The exploration of S. levis' perception and attraction behavior to these different substrates and volatile compounds provided insights and promising perspectives to improve monitoring techniques for this insect pest.
Estimativa de volume do tronco por reconstrução tridimensional e triangulação de contornos
(Universidade Federal de São Carlos, 2024-04-30) Bernardi, Lucas Kröhling; Thiersch, Claudio Roberto; https://lattes.cnpq.br/8791966697254106; https://orcid.org/0000-0003-1558-3168; Thiersch, Monica Fabiana Bento Moreira; https://lattes.cnpq.br/8465752697322536; https://orcid.org/0000-0001-8039-0253; https://lattes.cnpq.br/5626539122633461; https://orcid.org/0000-0002-7199-989X
Accurate quantification of wood volume is vital for sustainable forest management and serves as the basis for production planning. The methods for estimating the volume of wood present in the forest that rely on upper-stem diameter measurements assume that the stem can be approximated by the union of various sections of a geometric solid, which can result in inaccurate estimates. With the advancement of technology, new tools and methods are being developed to add greater precision and richness of information to forest inventories. Techniques such as digital image interpretation and sensors like terrestrial laser scanners can be applied to generate point clouds that can be converted into precise measurements of tree diameters and heights. This study proposes a new method of three-dimensional reconstruction of tree volume using digital photographs. The results show that the proposed method has potential application in the forestry sector due to its low cost and high precision, requiring only a digital camera and a studio box. Volume estimates using the proposed method, when compared to the volume obtained by the xylometer, were superior to conventional methods using caliper and measuring tape. Analysis of variance and the Tukey test at a 1% significance level indicated the use of digital images for obtaining the sectional area as the method with the lowest error compared to the xylometer (2.19%). The triangulation methods with two wooden discs (2.32%) and three discs (2.34%) were statistically equal to the caliper (2.72%). The measuring tape showed the worst results (6.03%). Under the analysis of scatter plots of residual distribution, the triangulation methods behaved similarly to the digital image method, being superior to the methods using caliper and measuring tape. Therefore, the proposed methods present themselves as promising alternatives to improve the accuracy of commercial volume estimates, contributing to the efficient and sustainable management of forest resources, especially in the context of estimating multiple products, where the knowledge of the stem shape is more important than the total individual tree volume.