Search results for: Rodrigo Denizarte de Oliveira Polkowski

Authors: Anésio de Leles Ferreira Filho, Wesley Rodrigues de Oliveira, Jéssica Santoro Gonçalves, Jorge Andrés Cormane Angarita

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The increase in electric power demand in face of environmental issues has intensified the participation of renewable energy sources such as photovoltaics, in the energy matrix of various countries. Due to their operational characteristics, they can generate time-varying harmonic and inter-harmonic distortions. For this reason, the application of methods of measurement based on traditional Fourier analysis, as proposed by IEC 61000-4-7, can provide inaccurate results. Considering the aspects mentioned herein, came the idea of the development of this work which aims to present the results of a comparative evaluation between a methodology arising from the combination of the Prony method with the Kalman filter and another method based on the IEC 61000-4-30 and IEC 61000-4-7 standards. Employed in this study were synthetic signals and data acquired through measurements in a 50kWp photovoltaic installation.

Keywords: harmonics, inter-harmonics, iec61000-4-7, parametric estimators, photovoltaic generation

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Authors: Luiz Carlos Dias Lima De Oliveira

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Psychology does not have the task of being confined only to the knowledge of losses, weaknesses or diseases, because it is necessary to give analogous dedication to the investigation of human virtues, efforts and aptitudes. The reasons for living with greater constancy and expressiveness act as a protective condition for risk behaviors, but with less constancy and expressiveness they can be a viable parameter of suicidal ideation or potential suicidal initiatives. In other words, Positive Psychology scientifically studies human strengths and virtues. In the same way, we refer to the basic psychological needs of the human being, according to the Theory of Self-Determination: the need for belonging, competence and autonomy to live the best possible life or the ability to make positive decisions in life. In this sense, following the assumptions of Positive Psychology, we raise the question of what are the reasons for living, seeking a way to draw attention to positive aspects of life.

Keywords: psychology, positive, self-determination, belonging, competence, autonomy, depression, suicide.

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Authors: Flávia M. Oliveira, Marcos V. Rodrigues, Mônica L. Aguiar

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Synthetic fibers are widely used in gas filtration. Previous attempts to optimize the filtration process have employed mixed fibers as the filter medium in gas-solid separation. Some of the materials most frequently used this purpose are composed of polyester, polypropylene, and glass fibers. In order to improve the retention of cement particles in bag filters, the present study investigates the use of synthetic glass fiber filters and polypropylene fiber for particle filtration, with electrostatic discharge of 0 to -2 kV in cement particles. The filtration curves obtained showed that charging increased the particle collection efficiency and lowered the pressure drop. Particle diameter had a direct influence on the formation of the dust cake, and the application of electrostatic discharge to the particles resulted in the retention of more particles, hence increasing the lifetime of fabric filters.

Keywords: glass fiber filter, particle, electrostatic discharge, cement

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Authors: S. S. Pati, L. Herojit Singh, A. C. Oliveira, V. K. Garg

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Chitosan functionalized Fe3O4-Au core shell nanoparticles have been prepared using a two step wet chemical approach using NaBH4 as reducing agent for formation of Au inethylene glycol. X-ray diffraction studies shows individual phases of Fe3O4 and Au in the as prepared samples with crystallite size of 5.9 and 11.4 nm respectively. The functionalization of the core-shell nanostructure with Chitosan has been confirmed using Fourier transform infrared spectroscopy along with signatures of octahedral and tetrahedral sites of Fe3O4 below 600cm-1. Mössbauer spectroscopy shows decrease in particle-particle interaction in presence of Au shell (72% sextet) than pure oleic coated Fe3O4 nanoparticles (88% sextet) at room temperature. At 80K, oleic acid coated Fe3O4 shows only sextets whereas the Chitosan functionalized Fe3O4 and Chitosan functionalized Fe3O4@Au core shell show presence of 5 and 11% doublet, respectively.

Keywords: core shell, drug delivery, gold nanoparticles, magnetic nanoparticles

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Authors: Rodrigo Buaiz Boabaid

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Tokenization of Blue Bonds is an emerging Green Finance tool that has the potential to scale Blue Carbon Projects to fight climate change. This innovative solution has a huge potential to democratize the green finance market and catalyze innovations in the climate change finance sector. Switzerland has emerged as a leader in the Green Finance space and is well-positioned to drive the adoption of Tokenization of Blue & Green Bonds. This unique approach has the potential to unlock new sources of capital and enable global investors to participate in the financing of sustainable blue carbon projects. By leveraging the power of blockchain technology, Tokenization of Blue Bonds can provide greater transparency, efficiency, and security in the investment process, while also reducing transaction costs. Investments are in line with the highest regulations and designed according to the stringent legal framework and compliance standards set by Switzerland. The potential benefits of Tokenization of Blue Bonds are significant and could transform the way that sustainable projects are financed. By unlocking new sources of capital, this approach has the potential to accelerate the deployment of Blue Carbon projects and create new opportunities for investors to participate in the fight against climate change.

Keywords: blue carbon, blue bonds, green finance, Tokenization, blockchain solutions

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Authors: Luis Rodrigo Valencia Perez, Francisco Flores Aguero, Gibran Aguilar Rangel

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Artificial Intelligence (AI) is rapidly transforming diverse sectors, and higher education in Latin America is no exception. This article explores the impact of AI on higher education institutions in the region, highlighting the imperative need for well-trained teachers in emerging technologies and a cultural shift towards the adoption and efficient use of these tools. AI offers significant opportunities to improve learning personalization, optimize administrative processes, and promote more inclusive and accessible education. However, the effectiveness of its implementation depends largely on the preparation and willingness of teachers to integrate these technologies into their pedagogical practices. Furthermore, it is essential that Latin American countries develop and implement public policies that encourage the adoption of AI in the education sector, thus ensuring that institutions can compete globally. Policies should focus on the continuous training of educators, investment in technological infrastructure, and the creation of regulatory frameworks that promote innovation and the ethical use of AI. Only through a comprehensive and collaborative approach will it be possible to fully harness the potential of AI to transform higher education in Latin America, thereby boosting the region's development and competitiveness on the global stage.

Keywords: artificial intelligence (AI), higher education, teacher training, public policies, latin america, global competitiveness

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Authors: S. S. Silva, S. M. A. Souza, C. F. P. Oliveira

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Brazil's agriculture is a major economic base in the country; in addition, family farming is directly responsible for the production of most agricultural products in Brazil, such as cassava. The number of studies on the use of cassava and its derivatives in the food industry has been increased, which is the basis of this study. Sought to develop a food that take advantage the products from farmers, adding value to these products and to study its effects as a replacement for wheat flour. For such elaborated a gluten-free cake – aiming to meet the needs of the celiac public – containing cassava flour, cane sugar, honey, egg, soya oil, coconut desiccated, baking powder and water. For evaluation of their characteristics technological, physicochemical and texture characterizations were done. Cake showed similar characteristics of cake made with wheat flour and growth and aeration of the dough. In sum up, marketing the product is viable, in that it has a typical overall appearance of cake made of wheat flour, meet the needs of celiac people and value the family farming.

Keywords: baking, cake, cassava flour, celiac disease

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Authors: L. P. Nascimento, M. Soares, N. Valério, A. Ribeiro, J. R. M. Oliveira, J. Araújo, C. Vilarinho, J. Carvalho

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With the growing need to save natural resources and value waste that was previously worthless, waste recycling becomes imperative. Thus, with the techno-scientific growth and in the perspective of sustainability, it is observed that waste has the potential to replace significant percentages of materials considered “virgin”. An example is the replacement of crushed aggregates with foundry sand. In this work, a mix design study of two asphalt mixes, a base mix (AC 20) and a surface mix (AC14) was carried out to evaluate the maximum amount of foundry sand residue that could be used. Water sensitivity tests were performed to evaluate the mechanical behavior of these mixtures. For the superficial mixture with foundry sand (AC14FS), the maximum of sand used was 5%, with satisfactory results of sensitivity to water. In the base mixture with sand (AC20FS), the maximum of sand used was 12%, which had less satisfactory results. However, from an environmental point of view, the re-incorporation of this residue in the pavement is beneficial because it prevents it from being deposited in landfills.

Keywords: foundry sand, hot mix asphalt, industrial waste, waste valorization, sustainability

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Authors: Orhun Aydin, Mark V. Janikas, Rodrigo Alves, Renato Assuncao

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In this paper, a tree-based perturbation methodology for regionalization inference is presented. Regionalization is a constrained optimization problem that aims to create groups with similar attributes while satisfying spatial contiguity constraints. Similar to any constrained optimization problem, the spatial constraint may hinder convergence to some global minima, resulting in spatially contiguous members of a group with dissimilar attributes. This paper presents a general methodology for rigorously perturbing spatial constraints through the use of random spanning trees. The general framework presented can be used to quantify the effect of the spatial constraints in the overall regionalization result. We compare several types of stochastic spanning trees used in inference problems such as fuzzy regionalization and determining the number of regions. Performance of stochastic spanning trees is juxtaposed against the traditional permutation-based hypothesis testing frequently used in spatial statistics. Inference results for fuzzy regionalization and determining the number of regions is presented on the Local Area Personal Incomes for Texas Counties provided by the Bureau of Economic Analysis.

Keywords: regionalization, constrained clustering, probabilistic inference, fuzzy clustering

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Authors: Khalida Douibi, Rodrigo Balp, Solène Le Bars

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In the medical field, applications related to human experiments are frequently linked to reduced samples size, which makes the training of machine learning models quite sensitive and therefore not very robust nor generalizable. This is notably the case in Brain-Computer Interface (BCI) studies, where the sample size rarely exceeds 20 subjects or a few number of trials. To address this problem, several resampling approaches are often used during the data preparation phase, which is an overly critical step in a data science analysis process. One of the naive approaches that is usually applied by data scientists consists in the transformation of the entire database before the resampling phase. However, this can cause model’ s performance to be incorrectly estimated when making predictions on unseen data. In this paper, we explored the effect of data leakage observed during our BCI experiments for device control through the real-time classification of SSVEPs (Steady State Visually Evoked Potentials). We also studied potential ways to ensure optimal validation of the classifiers during the calibration phase to avoid overfitting. The results show that the scaling step is crucial for some algorithms, and it should be applied after the resampling phase to avoid data leackage and improve results.

Keywords: data leackage, data science, machine learning, SSVEP, BCI, overfitting

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Authors: Gizelle K. Vianna, Gustavo S. Oliveira, Gabriel V. Cunha

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The use of decision support systems in agriculture may help monitoring large fields of crops by automatically detecting the symptoms of foliage diseases. In our work, we designed and implemented a decision support system for small tomatoes producers. This work investigates ways to recognize the late blight disease from the analysis of digital images of tomatoes, using a pair of multilayer perceptron neural networks. The networks outputs are used to generate repainted tomato images in which the injuries on the plant are highlighted, and to calculate the damage level of each plant. Those levels are then used to construct a situation map of a farm where a cellular automata simulates the outbreak evolution over the fields. The simulator can test different pesticides actions, helping in the decision on when to start the spraying and in the analysis of losses and gains of each choice of action.

Keywords: artificial neural networks, cellular automata, decision support system, pattern recognition

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Authors: Amanda Cristina de Oliveira, Elias de Souza Monteiro Filho, Roberta Ceriani

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Liquid-liquid extraction in aqueous two-phase systems (ATPSs) constitutes a powerful tool for purifying bio-materials, such as cells, organelles, proteins, among others. In this work, the extraction of the bovine serum albumin (BSA) has been studied in systems formed by polyethylene glycol (PEG) (1500, 4000, and 6000 g.mol⁻¹) + potassium sodium tartrate + water at 303.15°K. Phase diagrams were obtained by turbidimetry and Merchuk’s method (1998). The experimental tie-lines were described using the Othmer-Tobias and Bancroft correlations. ATPSs were correlated with the nonrandom two-liquid (NRTL) model. The results were considered excellent according to global root-mean-square deviations found which were between 0,72 and 1,13%. The concentrations of the proteins in each phase were determined by spectrophotometry at 280 nm, finding partition efficiencies greater than 71%.

Keywords: aqueous two phases systems, bovine serum albumin , liquid-liquid extraction, polyethylene glycol

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Authors: Stephanie M. De Oliveira

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For a long time, migrations are characterized as a difficult problem to solve. Various phenomena throughout human history caused personnel migrations, whether by the free will of migrants or not. Nowadays, governments that seek to give these people protection and dignity, either to asylum or to build a new life in a different country, make refugee protection. At present, a large amount of people, have been crossing their country's borders by land, air or sea, becoming refugees and seeking a new life away from fear, threat or violence they suffered in their country of origin. It is known that some countries have already instituted rights and rules for refugees who wish to become citizens in the country to which they immigrated, even though this is not what happens in most cases. The article will be based on research made with UN Refugee Agency (UNHCR) material as well as will analyze the interaction of the Turkish government with the European Union. Since Turkey is not part of the Union, it will be understood how the interaction was made, as well as the search for consensus, and not only humanitarian but also financial aid. The treatment of refugees and the defense of human rights within the country will also be considered.

Keywords: refugees, Turkey, asylum seekers, United Nations

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Authors: Lukasz Grzegorz Broda, Taiwo Oseni, Andrew Stranieri, Rodrigo Marino, Ronelle Welton, Mark Yates

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The oral health of residents in aged care centres in Australia is poor, contributing to infections, hospital admissions, and increased suffering. Although the use of electric toothbrushes has been deployed in many centres, smartbrushes that record and transmit information about brushing patterns and duration are not routinely deployed. Yet, the use of smartbrushes for aged care residents promises better oral care. Thus, a study aimed at investigating the appropriateness and suitability of a smartbrush for aged care residents is currently underway. Due to the peculiarity of the aged care setting, the incorporation of smartbrushes into residents’ care does require careful planning and design considerations. This paper describes an initial design process undertaken through the use of an actor to understand the important elements to be incorporated whilst installing a smartbrush for use in aged care settings. The design covers the configuration settings of the brush and app, including ergonomic factors related to brush and smartphone placement. A design science approach led to an installation re-design and a revised protocol for the planned study, the ultimate aim being to design installations to enhance perceived usefulness, ease of use, and attitudes towards the incorporation of smartbrushes for improving oral health care for aged care residents.

Keywords: smartbrush, applied computing, life and medical sciences, health informatics

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Authors: Suarez-Puello Alejandro, Baquero-Ruiz Andrés F, Suarez-Puello Rodrigo

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This paper discusses the results of a foresight exercise which analyzes Bogota’s fruit, vegetable and tuber supply chain strategy- described at the Food Supply and Security Master Plan (FSSMP)-to provide the inhabitants of Bogotá, Colombia, with basic food products at a fair price. The methodology consisted of using quantitative and qualitative foresight tools such as system dynamics and variable selection methods to better represent interactions among stakeholders and obtain more integral results that could shed light on this complex situation. At first, the Master Plan is an input to establish the objectives and scope of the exercise. Then, stakeholders and their relationships are identified. Later, system dynamics is used to model product, information and money flow along the fruit, vegetable and tuber supply chain. Two scenarios are presented, discussing actions by the public sector and the reactions that could be expected from the whole food supply system. Finally, these impacts are compared to the Food Supply and Security Master Plan’s objectives suggesting recommendations that could improve its execution. This foresight exercise performed at a governmental level is intended to promote the widen the use of foresight as an anticipatory, decision-making tool that offers solutions to complex problems.

Keywords: decision making, foresight, public policies, supply chain, system dynamics

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Authors: Anderson Rocha, Pedro Miguel de Figueiredo Dinis Oliveira Gaspar

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Machine vision has been widely used in recent years in agriculture, as a tool to promote the automation of processes and increase the levels of productivity. The aim of this work is the development of a path recognition algorithm based on image processing to guide a terrestrial robot in-between tree rows. The proposed algorithm was developed using the software MATLAB, and it uses several image processing operations, such as threshold detection, morphological erosion, histogram equalization and the Hough transform, to find edge lines along tree rows on an image and to create a path to be followed by a mobile robot. To develop the algorithm, a set of images of different types of orchards was used, which made possible the construction of a method capable of identifying paths between trees of different heights and aspects. The algorithm was evaluated using several images with different characteristics of quality and the results showed that the proposed method can successfully detect a path in different types of environments.

Keywords: agricultural mobile robot, image processing, path recognition, hough transform

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Authors: Nivon P. Alejandra, Valencia P. L. Rodrigo, Vivanco V. Martin, Morita A. Adelina

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Technological innovation is fundamental to reach and maintain the levels of competitiveness of agricultural producers, the detection of actors, their activities, resources and capacities of an innovation system is needed for the development of technological packages that adapt to each type of crops, local circumstances and characteristics of the producer. The growing development of the viticulture and wine sector in Mexico prospects an increase in its national market participation for 2020, this is the reason to consider it a fertile field for the technological packages adoption that promote Precision Agriculture (PA) in a harmonic and sustainable development. A viability inspection of technological packages adoption by viticulture and wine sector is made following the methodology proposed by SAGARPA in 2015 and the World Bank in 2008: the history, actors, strengths and opportunities are analyzed in this particular agroindustrial sector, also its technological innovation system is inspected in order to improve technological capacities and innovation networks taking into account local and regional resources. PA and technological packages adoption can help improving the conditions and quality of the grape for winemaking: increasing the wine's storage potential and its nutraceutical nature. The assertive diagnosis in vineyard opportunity areas will help the management of the crop by applying natural treatments at the right time in the right place.

Keywords: technological packages, precision farming, sustainable development, innovation

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Authors: J. H. O. Nascimento, F. R. Oliveira, K. K. O. S. Silva, J. Neves, V. Teixeira, J. Carneiro

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These the aliphatic polyesters such as Polylactic Acid (PLA) in the form of fibers, nanofibers or plastic films, generally possess chemically inert surfaces, free porosity, and surface free energy (ΔG) lesser than 32 mN/m. It is therefore considered a low surface energy material, consequently has a low work of adhesion. For this reason, the products manufactured using these polymers are often subjected to surface treatments in order to change its physic-chemical surface, improving their wettability and the Work of Adhesion (WA). Plasma Radio Frequency low pressure (RF) treatment was performed in order to improve the Work of Adhesion (WA) on PLA fibers. Different parameters, such as, power, ratio of working gas (Argon/Oxygen) and treatment time were used to optimize the plasma conditions to modify the PLA surface properties. With plasma treatment, a significant increase in the work of adhesion on PLA fiber surface was observed. The analysis performed by XPS showed an increase in polar functional groups and the SEM and AFM image revealed a considerable increase in roughness.

Keywords: RF plasma, surface modification, PLA fabric, atomic force macroscopic, Nanotechnology

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Authors: Eric Wilson Santos Cabral, Marta Monteiro Da Costa Cruz, Fabio Luis Maciel Machado, Henrique Andrade, Rodrigo Pirola Pestana, Vivian Andrea Parreira

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The large variation in the price of diesel in Brazil directly affects the variable cost of companies operating in the transportation sector. In rail transport, the great challenge is to overcome the annual budget, cargo and ore transported with cost reduction in relation to previous years, becoming more efficient every year. Some effective measures are necessary to achieve the reduction of the liter ratio consumed by KTKB (Gross Ton per Kilometer multiplied by thousand). This acronym represents the indicator of energy efficiency of some railroads in the world. This study is divided into two parts: the first, to identify using statistical tools, part of the controlled variables in the railways, which have a correlation with the energy efficiency indicator, seeking to aid decision-making. The second, with the use of the train dynamics simulator, within scenarios defined in the operational reality of a railroad, seeks to optimize the train formations and the train stop model for the change of train drivers. With the completion of the study, companies in the rail sector are expected to be able to reduce some of their transportation costs.

Keywords: railway transport, railway simulation, energy efficiency, fuel consumption

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Authors: Rafael Oliveira Santos, Luciano Pessanha Moreira, Marcelo Costa Cardoso

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Spacer grid assembly supporting the nuclear fuel rods is an important concern in the design of structural components of a Pressurized Water Reactor (PWR). The spacer grid is composed by springs and dimples which are formed from a strip sheet by means of blanking and stamping processes. In this paper, the blanking process and tooling parameters are evaluated by means of a 2D plane-strain finite element model in order to evaluate the punch load and quality of the sheared edges of Inconel 718 strips used for nuclear spacer grids. A 3D finite element model is also proposed to predict the tooling loads resulting from the stamping process of a preformed Inconel 718 strip and to analyse the residual stress effects upon the spring and dimple design geometries of a nuclear spacer grid.

Keywords: blanking process, damage model, finite element modelling, inconel 718, spacer grids, stamping process

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Authors: Juliane P. De Oliveira, Carlos H. Dos Santos, Marcia Shoji, Maria E. C. Ferreira, Natalia U. Yamaguchi

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The construction sector is considered a major generator of environmental impacts due to the high consumption of natural resources and waste generation. Thus, this article aims to evaluate the performance of a concrete produced by the partial and total replacement of natural coarse aggregate by recycled coarse aggregate, derived from the concrete residue of buildings and demolitions. The study was made by comparing the compressive strength and absorption of three different concrete traces, keeping the water/cement factor of 0.60 and changing only the proportions of recycled coarse aggregate between 0%, 50% and 100%. Traces 50% and 100% obtained good results by comparing the actual specific mass, because the material used is lighter to the natural coarse aggregate. It was concluded that the concrete produced with recycled aggregates, even with inferior results, can be used where it is not needed a structural function, giving an adequate destination to the construction and demolition waste and consequently reducing the extraction and consumption of natural resources.

Keywords: green concrete, recycled aggregate, recycling, sustainable development

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Authors: Ruben Dario Tovar-Valencia, Eshan Ganju, Fei Han, Monica Prezzi, Rodrigo Salgado

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Particle breakage occurs even in strong silica sand particles. There is compelling evidence that suggests that particle breakage causes changes in several properties such as permeability, peak strength, dilatancy and critical state friction angle. Current pile design methods that are based on soil properties do not account for particle breakage that occurs during driving or jacking of displacement piles. This may lead to significant overestimation of pile capacity in sands dominated by particles susceptible to breakage, such as carbonate sands. The objective of this paper is to study the influence of shear displacement on particle breakage and friction angle of carbonate sands, and to furthermore quantify the change in friction angle observed with different levels of particle breakage. To study the phenomenon of particle breakage, multiple ring shear tests have been performed at different levels of vertical confinement on a thoroughly characterized carbonate sand to find i) the shear displacement necessary to reach stable friction angles and ii) the effect of particle breakage on the mobilized friction angle of the tested sand. The findings of this study can potentially be used to update the current pile design methods by developing a friction angle which is a function of shear displacement and breakage characteristics of the sand instead of being a constant value.

Keywords: breakage, carbonate sand, friction angle, pile design, ring shear test

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Authors: M. Eckert, M. Oliveira

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The intensive use of natural aggregates, near cities and towns, associated to the increase of the global population, leads to its depletion and increases the transport distances. The uncontrolled deposition of construction and demolition waste in landfills and city outskirts, causes pollution and takes up space. The use of recycled aggregates in concrete preparation would contribute to mitigate the problem. However, it arises the problem that the high water absorption of recycled aggregate decreases the bleeding rate of concrete, and when this gets lower than the evaporation rate, plastic shrinkage cracking occurs. This phenomenon can be particularly problematic in hot and windy curing environments. Cracking facilitates the flow of liquid and gas into concrete which attacks the reinforcement and degrades the concrete. These factors reduce the durability of concrete structures and consequently the lifetime of buildings. A ring test was used, cured in a wind tunnel, to evaluate the plastic shrinkage cracking sensitivity of recycled aggregate concrete, in order to implement preventive means to control this phenomenon. The role of several aggregate properties on the concrete segregation and cracking mechanisms were also discussed.

Keywords: recycled aggregate, plastic shrinkage cracking, wind tunnel, durability

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Authors: Débora C. G. Oliveira, Julio D. Salles, Bruna A. Moriy, João A. Rossignolo, Holmer Savastano Jr.

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The objective of this study was to identify the optimal level of partial replacement of Portland cement by the ashes originating from burning straw and bagasse from sugar cane (ASB). Order to this end, were made five series of flat plates and cylindrical bodies: control and others with the partial replacement in 20, 30, 40, and 50% of ASB in relation to the mass of the Ordinary Portland cement, and conducted a mechanical testing of simple axial compression (cylindrical bodies) and the four-point bending (flat plates) and determined water absorption (WA), bulk density (BD) and apparent void volume (AVV) on both types of specimens. Based on the data obtained, it may be noted that the control treatment containing only Portland cement, obtained the best results. However, the cylindrical bodies with 20% ashes showed better results compared to the other treatments. And in the formulations plates, the treatment which showed the best results was 30% cement replacement by ashes.

Keywords: modulus of rupture, simple axial compression, waste, bagasse sugarcane

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Authors: Ana P. R. N. Barroso, Maurício N. Kleinberg, Frederico R. Silva, Rodrigo F. Guimarães, Marcelo M. V. Parente, Walney S. Araújo

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The fight against accelerated wear of the equipment used in the oil and gas sector is a challenge for minimizing maintenance costs. Corrosion being one of the main agents of equipment deterioration, we seek alternative materials that exhibit improved corrosion resistance at low cost of production. This study aims to evaluate the corrosion behavior of experimental alloys containing 15% and 17% of chromium (Cr) and 5% of molybdenum (Mo) in comparison with an AISI 444 commercial alloy. Microstructural analyzes were performed on samples of the alloys before and after the electrochemical tests. Two samples of each solubilized alloy were also taken for analysis of the corrosion behavior by testing potentiodynamic polarization (PP) and Electrochemical Impedance Spectroscopy (EIS) with immersion time of 24 hours in electrolytic solution with acidic character. The graphics obtained through electrochemical tests of PP and EIS indicated that among the experimental alloys, the alloy with higher chromium content (17%) had a higher corrosion resistance, confirming the beneficial effect of adding chromium. When comparing the experimental alloys with the AISI 444 commercial alloy, it is observed that the AISI 444 commercial alloy showed superior corrosion resistance to that of the experimental alloys for both assays, PP and EIS. The microstructural analyzes performed after the PP and EIS tests confirmed the results previously described. These results suggest that the addition of these levels of molybdenum did not favor the electrochemical behavior of experimental ferritic alloys for the electrolytic medium studied.

Keywords: corrosion, molybdenum, electrochemical tests, experimental alloys

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Authors: Mona Lisa M. Oliveira, Nara A. Policarpo, Ana Luiza B. P. Barros, Carla A. Silva

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Selective catalytic reduction systems for nitrogen oxides reduction by ammonia has been the chosen technology by most of diesel vehicle (i.e. bus and truck) manufacturers in Brazil, as also in Europe. Furthermore, at some conditions, over-stoichiometric ammonia availability is also needed that increases the NH₃ slips even more. Ammonia (NH₃) by this vehicle exhaust aftertreatment system provides a maximum efficiency of NOx removal if a significant amount of NH₃ is stored on its catalyst surface. In the other words, the practice shows that slightly less than 100% of the NOx conversion is usually targeted, so that the aqueous urea solution hydrolyzes to NH₃ via other species formation, under relatively low temperatures. This paper presents a model based on neural networks integrated with a road vehicle simulator that allows to estimate NH₃-slip emission factors for different driving conditions and patterns. The proposed model generates high NH₃slips which are not also limited in Brazil, but more efforts needed to be made to elucidate the contribution of vehicle-emitted NH₃ to the urban atmosphere.

Keywords: ammonia slip, neural-network, vehicles emissions, SCR-NOx

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Authors: C. S. Marques, M. J. Reis Lima, J. Oliveira, E. Teixeira-Lemos

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The growing concerns for physical wellbeing and health have been reflected in the way we choose food in our table. Nowadays, we are all more informed consumers and choose healthier foods. On the other hand, stroke, cancer and atherosclerosis may be somehow minimized by the intake of some bioactive compounds present in food, the so-called nutraceuticals and functional foods. The aim of this work was to make a revision of the published studies about the effects of some bioactive compounds, namely lycopene in human health, in the prevention of diseases, thus playing the role of a functional food. Free radical in human body can induce cell damage and consequently can be responsible for the development of some cancers and chronic diseases. Lycopene is one of the most powerful antioxidants known, being the predominant carotenoid in tomato. The respective chemistry, bioavailability, and its functional role in the prevention of several diseases will be object of this work. On the other hand the inclusion of lycopene in some foods can also be made by biotechnology and represents a way to recover the wastes in the tomato industry with nutritional positive effects in health.

Keywords: tomato, lycopene, bioavailability, functional foods, carotenoids, cancer and antioxidants

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Authors: Gastão Soares Ximenes de Oliveira, Richar Nicolás Durán, Romeo Micah Szmoski, Eloiza Aparecida Avila de Matos, Elano Gustavo Rein

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This article aims to present an experimental method to determine Planck's constant by calculating the cutting potential V₀ from LEDs with different wavelengths. The experiment is designed using Arduino as a central tool in order to make the experimental activity more engaging and attractive for students with the use of digital technologies. From the characteristic curves of each LED, graphical analysis was used to obtain the cutting potential, and knowing the corresponding wavelength, it was possible to calculate Planck's constant. This constant was also obtained from the linear adjustment of the cutting potential graph by the frequency of each LED. Given the relevance of Planck's constant in physics, it is believed that this experiment can offer teachers the opportunity to approach concepts from modern physics, such as the quantization of energy, in a more accessible and applied way in the classroom. This will not only enrich students' understanding of the fundamental nature of matter but also encourage deeper engagement with the principles of quantum physics.

Keywords: physics teaching, educational technology, modern physics, Planck constant, Arduino

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Authors: Matias Micheletto, Rodrigo Santos, Sergio F. Ochoa

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In developing countries, the most roads in rural areas are dirt road. They require frequent maintenance since are affected by erosive events, such as rain or wind, and the transit of heavy-weight trucks and machinery. Early detection of damages on the road condition is a key aspect, since it allows to reduce the main-tenance time and cost, and also the limitations for other vehicles to travel through. Most proposals that help address this problem require the explicit participation of drivers, a permanent internet connection, or important instrumentation in vehicles or roads. These constraints limit the suitability of these proposals when applied into developing regions, like in Latin America. This paper proposes an alternative method, based on unattended crowdsensing, to determine the quality of dirt roads in rural areas. This method involves the use of a mobile application that complements the road condition surveys carried out by organizations in charge of the road network maintenance, giving them early warnings about road areas that could be requiring maintenance. Drivers can also take advantage of the early warnings while they move through these roads. The method was evaluated using information from a public dataset. Although they are preliminary, the results indicate the proposal is potentially suitable to provide awareness about dirt roads condition to drivers, transportation authority and road maintenance companies.

Keywords: dirt roads automatic quality assessment, collaborative system, unattended crowdsensing method, roads quality awareness provision

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Authors: Miguel José Oliveira, Fátima Farinha, Elisa M. J. da Silva, Rui Lança, Manuel Duarte Pinheiro, Cátia Miguel

Abstract:

The Observatory of Sustainability of the Algarve Region for Tourism (OBSERVE) will be a valuable tool to assess the sustainability of this region. The OBSERVE tool is designed to provide data and maintain an up-to-date, consistent set of indicators defined to describe the region on the environmental, sociocultural, economic and institutional domains. This ongoing two-year project has the active participation of the Algarve’s stakeholders, since they were consulted and asked to participate in the discussion for the indicators proposal. The environmental and sociocultural indicators chosen must indicate the characteristics of the region and should be in alignment with other global systems used to monitor the sustainability. This paper presents a review of sustainability indicators systems that support the first proposal for the environmental and sociocultural indicators. Others constraints are discussed, namely the existing data and the data available in digital platforms in a format suitable for automatic importation to the platform of OBSERVE. It is intended that OBSERVE will be a valuable tool to assess the sustainability of the region of Algarve.

Keywords: Algarve, development, environmental indicators, observatory, sociocultural indicators, sustainability, tourism

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