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A frictional contact problem between a thermo-piezoelectric body and a thermally conductive foundation is numerically studied in this paper. The material’s behaviour is described by means of a thermo-electro-elastic constitutive law. The process is quasistatic, the contact is bilateral and is associated to Tresca’s law for dry friction. Hybrid formulation is introduced, it is a coupled system for the displacement field, the electric potential, the temperature and two Lagrange multipliers. The discrete scheme of the coupled system is introduced based on a finite element method to approximate the spatial variable and an Euler scheme to discretize the time derivate. The frictional contact is treated by using an augmented Lagrangian approach and a version of Newton’s method. A solution algorithm is discussed and implemented. Finally, numerical simulation results are reported. These simulations show the performance of the algorithm and illustrate the effects of the conductivity of the foundation, as well.

Quality is the most important aspect of fastener production for maintaining competitiveness and customer satisfaction. Nowadays, the quality control process is uncertain and complicated. Cold forging is used to produce preform fasteners via various processes. As a traditional measure of cold forging, quality prediction can be done using the normal probability method, but this approach is not effective or accurate enough. This paper proposes a novel quality prediction for preform fasteners using a fuzzy inference system and DEFORM simulation using an engineering software called DEFORM® system that can analyze metal forming. Multi-factors and criteria are considered, consisting of deformability, defects, stress, and time. The developed modeling can predict the cold forging quality at the stage of product design, which can associate decision making with production control. It can eliminate defects and reduce cost and time to rework. The case study is illustrated on the cold heading of stainless 341 using DEFORM, whereas the modeling is simulated by MATLAB.

El objetivo de este trabajo es analizar la intención emprendedora en el marco de las características personales y factores del entorno de las mujeres del curso académico denominado Proyecto emprendedor, de los programas presenciales de cuatro facultades de una universidad en Bucaramanga, Colombia. La metodología se estructuró bajo un enfoque cuantitativo y tuvo un diseño no experimental, de corte transversal y explicativo. En tal sentido, se aplicó como fuente de información una encuesta conformada por 33 preguntas relacionadas con los factores objeto de estudio a 147 estudiantes, lo que permitió realizar un análisis descriptivo y correlacional. Los resultados revelan que existen diferencias significativas en la relación entre la intención emprendedora y las características personales y del entorno de las estudiantes de las cuatro facultades.

In this paper, optimal control theory is applied to Herpes Simplex Virus-II transmission model given by a system of non-linear ordinary differential equations. Optimal control strategy was employed to study the level of effort needed to control the transmission dynamics of HSV-II diseases using three controls; prevention, screening and treatment control strategies. The necessary conditions for the existence of the optimal controls was established using Pontryagin’s Maximum Principle. Optimal control system was performed with help of Runge-Kutta forward-backward sweep numerical approximation method. Finally, numerical simulations reveal that a combination of prevention, screening and treatment is the most effective strategy to eradicate the disease from the community.

Las nuevas tecnologías continúan cambiando esquemas y formas de gestionar información de procesos industriales. Con ellas han surgido también cambios en la forma como la sociedad actual se relaciona, se comunica, cómo entiende las interacciones entre personas, cómo encuentra nuevas motivaciones asociadas al uso de la tecnología. Este trabajo se centra en estudiar la motivación generada en una clase de pregrado universitario a la cual se incorporó una herramienta gamificada estándar en el mercado para la enseñanza y el aprendizaje del curso. Los contenidos de la clase tienen relación directa con la integración de tecnología en los procesos de negocio, y los estudiantes incluidos en la muestra están en quinto año de un programa de ingeniería. Los resultados muestran que los estudiantes prefieren ampliamente una clase gamificada, pero que, al mismo tiempo, algunos de los elementos de la gamificación, entre ellos los que tienen que ver con efectos aleatorios, no son bien percibidos, mientras que los avatares dan sentido al desarrollo de una comunidad virtual con nuevas identidades personales, lo cual llama profundamente la atención de los jóvenes de educación media.

En Colombia se presenta un desconocimiento en materia de educación financiera, lo cual contrasta con un aumento del interés por aprender temas enfocados en finanzas. Esto, en términos académicos, refleja una brecha entre la existencia de herramientas de enseñanza a niveles de educación media y superior, y su efectividad real en los estudiantes. En aras de contribuir a llenar esa brecha y contribuir a la alfabetización financiera a nivel universitario, se propone el diseño de un ejercicio lúdico dinámico y amigable relacionado con una simulación de inversión en la bolsa de valores de una empresa específica. Para el diseño, se utilizó la metodología de design thinking. Resultó una lúdica que busca proporcionar una introducción para los estudiantes al tema de los mercados de capitales y generar un interés orgánico en ellos. A partir de esto, se espera probar la lúdica en un grupo piloto y validar su funcionamiento, a fin de aportar, por medio de la gamificación, bases sólidas que den paso al progreso de la alfabetización financiera en la educación superior.

The main objective of power transmission and distribution companies is to provide reliable power with minimal Customer Interruptions (CI) and Customer Interruption Minutes (CMI). For these companies, processes and tools that accurately predict the reliability and availability is very important. Studies have shown that the Reliability Block Diagram (RBD) simulation methodology provides more precise results than other methods. Also, the use of field data produces specific and more accurate results than using generalized failure rates for the substation equipment. In this paper, we present how the RBD technique is used to develop precise reliability models for 120 substations using field data. Failure data from over 7000 pieces of equipment was collected, and Weibull distribution was used to create hazard functions for the models. Since substation equipment is repairable, the Restoration Factor (RF) played an essential role in the reliability analysis. A mixed analysis is used to calculate the RF. This paper presents the procedure and methodology used to develop the reliability models, perform a Monte Carlo Simulation, and calculate the CI and CMI for each substation. In addition, the case study shows how unique modeling and statistical methods can be used to perform reliability assessments when individual equipment failure data is not available.

Breast cancer (BC) is the largest cause of death in women. Accurate classification of breast cancer data is important in cancer diagnosis and classification of Malignant and Benign tumors can prevent patients to take unnecessary tests. Breast cancer classification can also be used to determine suitable treatment. Classification of Benign and Malignant patient groups is widely recognized research in the medical field. Due to the advantage of detecting critical features from a medical data set, machine learning is widely used in Breast cancer Prediction. Recently there has been greater attention to the use of machine learning methods in medical diagnosis. These decision support systems are effective and helpful for medical experts in the healthcare domain. The objective of this work is to address the problem of the classification of breast cancer data using ensemble learning. Ensemble learning techniques are used to improve the performance of a classifier. This paper deals with building a decision support system using the ensemble model built with Bayesian network and Radial Basis Function. In this work, extensive experiments were carried out on the much- studied open access data set “Wisconsin Breast Cancer Data set (WBCD)”. The data set is partitioned into training and testing. Various metrics like accuracy, sensitivity, specificity, positive predictive value, negative predicted value, Error rate, false-positive rate, Mathew’s correlation coefficient were used to measure the performance of the model. Experimental results show that the proposed method records a remarkable accuracy of 97% to classify breast cancer data and outperformed the existing approaches. The proposed ensemble learning would be viable in helping cancer specialists in recognizing cancer tumors accurately and help the patients in taking the correct treatment.

A indústria tem forte interesse sobre a Genipa americana L. para produção de corante a partir do extrato ou suco do fruto. Atualmente, tem-se utilizado o extrato para formulação de agentes e loções corporais antioxidantes, tintura alimentícia e para tatuagem e produtos antileucemicos. Estas novas tecnologias estão embasadas em sua composição quimica com presença de flavonóides e, principalmente, iridóide genipin. O estudo teve por finalidade apresentar o estado da arte sobre a atividade biológica sobre o uso de extrato do jenipapeiro. Observou-se com o trabalho que não há produtos ou formulação relacionando a G. americana L com as atividades biológicas de cicatrização, antimicrobiana, antiparasitária, sendo notificada ação antioxidante e antileucemica do extrato do fruto. Não foi referenciada a produção de gel e microemulsão contendo extrato ou óleo de fruto, folha ou entrecasca de jenipapeiro. No entanto, o principal produto relatado foi a produção de corante, sendo as empresas latino-americanas as maiores depositárias de patentes. Com isto, o estudo mostra que há uma área ainda inexplorada sobre a potencialidade do jenipapeiro para diversos usos biológicos, não só para produção de corante a partir do pigmento azul do fruto.

En diferentes tipos de organización la estimación del tamaño de lotes de compra o producción es uno de los problemas frecuentes en la planeación de las cadenas de suministro, en las cuales participan estas unidades productivas. Esto se ha denominado el modelo de inventario de una sola vez o de “vendedor de periódicos”. De acuerdo con este principio, se realiza el diseño de una actividad lúdica aplicando la metodología cibernética de tercer orden, para facilitar el proceso de enseñanza-aprendizaje de un sistema, donde la estimación del tamaño de lote para compra o fabricación se centra en un artículo perecedero o con temporada de comercialización reducida, mediante un método inspirado en la teoría de la decisión. El escenario lúdico sucede en una tropa del ejército, en donde la enseñanza y el aprendizaje de conceptos y métodos de solución al problema se produce a través de la simulación de condiciones como demanda estocástica, con ciclos de producto y comercialización reducidos en un lapso de planeación para un artículo.

The study investigates properties of blended geopolymer based on fly ash (FA) and rice husk ash (RHA) activated with sodium aluminate as aluminum additive. Five series of geopolymer paste were studied with ratios of FA: RHA as 100:0, 75:25, 50:50, 25:75 and 0:100. Phase identification and quantification were performed by X-ray Diffraction (XRD). Fourier Transform Infrared Spectroscopy (FTIR), field emission scanning electron microscope (FESEM) were used to characterize the microstructure of the specimen. Quantification of the elements present were performed by Energy dispersion X-Ray Analysis (EDX). Compressive strength along with physical parameters such as bulk density, water absorption, sorptivity, apparent porosity was determined. Results shows that 25% replacement by RHA is the optimal percentage on physical-mechanical properties of the blended geopolymer. The finer particles of RHA filled the voids present in the geopolymer matrix through filling effect and enriched the gel which densify the specimen. SEM micrographs also validates the denser matrix of the specimen at the optimal replacement percentage. However, it was seen that blending of RHA with FA beyond the optimal 25% has a negative effect on the properties studied. The observation may be attributed due to the presence of zeolite X as confirmed by Quantitative XRD. Increase in the amount of zeolite X and its crystalline size has a negative impact on the compressive strength of the blended geopolymer. The present study is expected to provide a practical solution of utilizing FA and RHA solid waste in construction activities.

In this paper, recent developments of the devolatilization model and soot-formation model for the numerical simulations of pulverized-coal combustion fields, and the technology used to measure soot particles in pulverized-coal combustion fields are reviewed. For the development of new models, the validation of the developed models using measurement is necessary to check the accuracy of the models because new models without validation have a possibility to make large errors in simulations. We have developed the tabulated devolatilization process model (TDP model) that can take into account the effect of particle heating rate on the volatile matter amount and the devolatilization-rate parameters. The accuracy of the developed TDP model was validated by using the laser Doppler velocimetry data for the bench-scale coal combustion test furnace. The soot-formation model combined with TDP model for the large eddy simulation (LES) has been also developed. The spatial distributions of both the soot-volume fraction and the polycyclic aromatic hydrocarbons were measured by virtue of laser-induced incandescence (LII) and laser-induced chemiluminescence (PAHs-LIF). The accuracy of the developed soot-formation model was validated by using the measured data.

This study represented the catalytic pyrolysis of waste cooking oil (WCO) to produce biofuel via continuous reaction by using a pelleted Thai dolomite catalyst. The effect of calcination temperatures on catalyst synthesis was also examined in varying from 600 to 900°C for 2 h. Calcined Thai dolomite (CTD) samples were characterized by X-ray fluorescence spectrometer (XRF), thermo-gravimetric analysis (TGA) and differential-thermal analysis (DTA), X-ray diffractometer (XRD), N2 adsorption-desorption apparatus, and scanning electron microscope (SEM). In the catalytic pyrolysis process, the CTD catalysts were taken place in a packed bed pyrolysis reactor under atmospheric pressure for biofuel production in different reaction temperatures (450 to 550°C), and WHSV was about 0.5 h-1. The results were found that the effect of calcination temperature significantly altered the physicochemical properties of catalyst as well as the catalytic performance. The specific surface area and pore volume decreased with increasing the calcination temperatures. Besides, CaCO3 was transformed entirely into CaO at 900°C. For the catalytic pyrolysis process, the results were found that the highest pyrolytic yield was obtained at 500°C of reaction temperature using catalyst calcined at 700°C. Additionally, the results also expressed that the calcined temperature was significant in the quality of biofuel products. Moreover, the biofuel products can be separated into biogasoline, biokerosene, and biodiesel. The kinetic viscosity and heating value were satisfied following the standard values except for the acid value of all biofuel products. However, the acid value decreased when the CDT calcined at the highest temperature due to the obvious presenting of the CaO phase.

Green innovation has been valued as a mechanism to reduce environmental impacts, which can increase organizational commitment and engagement propensities for environmental sustainability. This paper aimed to understand: (1) how does green innovation recognition affect the organizational structure? and (2) how can organizational structure help most internal stakeholders commit and engage in the organization’s environmental objective? The data from 250 Thai heavy industrial organizations were collected. The results showed that there were significant relationships among green innovation recognition, organizational structure, and organizations’ environmental commitment and engagement. Besides, the intermediary role of differentiation and integration showed a significant influence on commitment and engagement. Our paper suggests that policymakers and entrepreneurs should introduce green innovation to their organizations to heighten the level of environmental sustainability in their strategy and policy.

State of charge (SOC) and state of health (SOH) of batteries are the indispensable control decision variables for online energy management system (EMS) in modern internal combustion engine vehicles. The real-time and accurate determination of SOC and SOH is essential to the reliability and safety of EMS operation. Obtaining good accuracy for the SOC estimation is difficult without considering SOH because of their coupling relationship. Although several works on the joint estimation of SOC and SOH of lithium–ion batteries are available, these studies cannot be applied to lead–acid batteries because of the differences in physical structure and characteristics. This study handles the problem of modeling the relationship between SOC and SOH of lead–acid battery and their online collaborative estimation. First, the structure and control strategy of a bus-based EMS is discussed, and the improper energy control actions of EMS due to the inaccurate SOC estimation are analyzed. Second, an instantaneous correlation factor β for SOC and SOH is defined as a new state estimating variable, and the simplified linear relationship model between β and open circuit voltage is established through the battery experiments. Third, a discretized augmented system equation of β is deduced according to the relationship model and the Randles circuit model. The least square circuit parameter identification (LSCPI) algorithm is presented to identify the time-varying circuit model parameters, while the adaptive Kalman filter for augmented system (AKFAS) algorithm is employed to estimate β online. A collaborative estimation algorithm is proposed on the basis of the LSCPI and AKFAS to determine SOC and SOH of lead–acid battery in real time, and a demo intelligent battery sensor is developed for its implementation. The results of battery charging and discharging experiments indicate that the proposed method has high accuracy. The estimation accuracy of SOC of this method reaches 3.13%, which is 7% higher than that of the existing method.

Esta investigación tiene el propósito de generar un procedimiento conforme a los requerimientos especificados en la guía de la CAR, por medio de la identificación de las actividades que realizan las organizaciones causantes de la emisión CO2, es decir, de gases efecto invernadero. Para esto se realizó una revisión de información en las empresas de Ingeniería, Procura y Construcción, entre septiembre de 2017 y julio de 2019, lo que permitió contar con una línea base lo suficientemente amplia para formular alternativas de compensación y metas de reducción en la generación de CO2. Como resultado se generó un procedimiento para la medición de los efectos del gas invernadero, mediante un formato, respetando los requerimientos de la guía metodológica de la CAR. Se encontró que los resultados fueron exitosos, con una participación del 93 % del total de personas. Se presentó el diseño específicamente, lo que evidencia el grado de compromiso por parte de los directivos en lo que respecta a temas de medioambiente. Con esto se hace énfasis en la importancia en apoyar proyectos de reforestación que aporten a disminuir la tasa de deforestación que presenta Colombia y que ha ido en aumento en los últimos años, según reporta el IDEAM.

Con la finalidad de favorecer la percepción del método enseñanza-aprendizaje activo para el tema del diseño del producto en la materia Administración de Operaciones I, se propone el diseño de una actividad lúdica llamada “Captura la idea” y un ejercicio para su validación. Para el diseño de la lúdica se utilizó la metodología Gamificación Canvas, y el referente teórico de la temática se basó en el modelo Mindshake Design Thinking Evolution 62. Para la validación, se realizó un estudio causal y cuasiexperimental para una muestra de 20 estudiantes con quienes se aplicaron dos encuestas tipo Likert. Los resultados permiten aceptar la hipótesis propuesta, y se concluye que el uso de esta estrategia mejora en promedio un 15 % la percepción del alumno. Adicionalmente, se evidenció que los estudiantes sienten que la clase es más estimulante, agradable y llamativa en comparación con una clase netamente magistral.

Este artículo de reflexión hace un recorrido por los conceptos de industrias culturales y creativas. Muestra la transición de los términos desde su visión cultural y artística hasta el entendimiento del papel de dichas industrias en el ecosistema económico. Su propósito estriba en el entendimiento de estas industrias como eje de desarrollo a partir de una visión política clara, con direccionamientos estratégicos identificados. Se realiza un análisis bibliométrico básico que permite identificar la importancia que tienen las industrias creativas en la actualidad, y también se hace una aproximación de su impacto a través de indicadores económicos mundiales y una lectura de la eficiencia de estas en la región. Se identifican los retos asociados a la industria y se proponen alternativas de abordaje en el contexto colombiano.

The triple-frequency linear combination with a low noise, a long wavelength, and a weak ionosphere is beneficial to effectively eliminate or weaken the common errors, advance the reliability of cycle slip detection and repair, and speed up the convergence time of fixed ambiguity. By establishing the Galileo triple-frequency carrier linear combination model, three types of linear combinations are derived: Geometry-free (GF) combinations, minimum noise (MN) combinations, and ionosphere-free (IF) combinations. The geometric relationships of these linear combinations are displayed in the form of image. The results indicate that the angle formed by the IF combinations and the MN combinations is between 75.02° and 86.01°, which also illustrates that it is more difficult to meet the carrier phase combinations with a low noise and a weak ionosphere. Moreover, to guarantee the integer cycle characteristics of ambiguity, the combination coefficient must be an integer. Galileo triple-frequency linear combination is solved utilizing the extremum method. To sum up, the sum of the coefficients of the extra wide lane (EWL) combinations and wide lane (WL) combinations is zero, and the sum of the coefficients of the narrow lane (NL) combinations is one. (0, 1, −1) is the optimal triple-frequency linear combination in Galileo. Three independent linear combinations are selected separately from the EWL, WL, and NL to jointly solve the integer ambiguity. Further, it creates a prerequisite for high-precision and real-time kinematic positioning.

Este estudio presenta un recorrido general por el diseño, creación y puesta en marcha de un objeto virtual de aprendizaje (OVA) creado bajo conceptos de la teoría de autogestión y la gamificación para la enseñanza en entornos universitarios, así como su posterior evaluación en términos de preferencia para el uso por parte de los estudiantes. Se parte de la conceptualización de los OVA y las bases teóricas en su construcción, pasando por las metodologías y dinámicas involucradas en su desarrollo, para finalmente mostrar los resultados de las pruebas de preferencia para el uso aplicadas a estudiantes universitarios. Con lo anterior, este OVA y su evaluación se exponen como un caso de estudio único en su tipo al involucrar la gamificación y el uso de este instrumento para abordar la enseñanza en cursos de sistemas de información en un pregrado en ingeniería industrial. Este análisis responde a preguntas como ¿cómo se construye un OVA con conceptos de gamificación? y ¿qué variables influyen en la preferencia del uso de esta herramienta?

O objetivo deste artigo foi analisar a literatura publicada sobre gordura animal como insumo para a produção de biodiesel por autores afiliados a organizações brasileiras de 2008 a 2019 por meio dos estudos métricos da informação. Para tanto, uma pesquisa exploratória-descritiva foi conduzida. Os dados revelaram uma taxa de crescimento médio da literatura na ordem de 21,15% no período analisado, com destaque para as indexadas nas áreas de Química e Engenharia. O nível de coautoria mais comum foi formado por grupos de seis autores e o coeficiente de colaboração médio mostrou-se elevado, indiferente da quantidade de documentos. A cooperação entre instituições nacionais mostrou-se forte, supostamente, graças a criação da Rede Brasileira de Tecnologia e Inovação em Biodiesel. Também foram identificadas as instituições mais produtivas. Observou-se que as pesquisas estão centradas no sebo bovino, mas pesquisas com gordura de frango e porco começaram a ganhar destaque.

El desarrollo sostenible es un tema de interés mundial, dado que busca proteger los recursos de las generaciones futuras. Es por esto que el Programa de las Naciones Unidas para el Desarrollo hace un llamado a la población a hacer uso de la creatividad y el conocimiento para proteger el planeta y garantizar que todas las personas gocen de paz y prosperidad para el año 2030, por medio del apoyo al cumplimiento de los Objetivos de Desarrollo Sostenible. Por tanto, en este artículo se describe el proceso mediante el cual se diseña una lúdica orientada a la promoción de los mencionados objetivos entre estudiantes de educación superior. La metodología usada fue el design thinking, con participación de integrantes del Laboratorio de Innovación Educativa GALEA. Los resultados permiten evidenciar que es factible diseñar una actividad que promueva la apropiación de los 17 Objetivos de Desarrollo Sostenible, y abre un espacio a futuro para la aplicación de la lúdica en entornos de clases, así como para su evaluación de impacto

The aim of this study was to evaluate and test the limitations of the Indian Standard code 456-2000 related to deep beams, given that the code does not have any provisions regarding the use of the strut and tie method (STM)of design. This study validates the use of truss reinforcement and STM-shaped reinforcements as alternatives to STM design. We conclude that horizontal web reinforcement has a greater impact than vertical shear reinforcement. Deep beams with truss reinforcement and STM-based reinforcement were shown to have the highest shear strength capacity of all the deep beams. In the present study, 21 deep beams were cast and used to analyze their shear and flexural behavior. The specimens were divided into four groups based on length, width and depth, percentage of tension reinforcement, and percentage of horizontal and vertical shear reinforcement. The results revealed that truss-type reinforcement configuration is stronger than vertical shear reinforcement, as the former can resist 20% more load than the latter.

Risks are inevitable during the construction phase of a project. In particular, contractors may respond to the project risks by accepting, avoiding, mitigating, or transferring the risks to other parties. This study aims to explore the use of insurance as one of the risk response mechanisms by contractors. Data were collected through observation of project documents and semi-structured interviews with contractors from five construction projects and four insurance companies. This research identified 42 risks, which are categorized into three levels: 26% low, 48% moderate, and 26% high. Of these, the contractors expected only 20 risks (48%) to be insured, whereas the insurance companies considered only 19 risks (45%) insurable. The risks were mapped on a four-quadrant matrix based on a combination of contractors' expectations for insuring or not insuring project risks, and the insurance company policies against those risks. The matrix revealed that 12 (29%) risks were ideal (insured-insurable), 7 (17%) were overlooked (uninsured-insurable), 15 (36%) were considered reasonable (uninsured-uninsurable), and 8 (19%) were categorized as critical (insured-uninsurable). These findings serve as a reference for the construction industry stakeholders in decision-making related to project risk management.

This paper proposes the use of explicit model predictive control (eMPC) method for the stabilising control of the nonlinear underactuated double inverted pendulum on a cart system. To access the effectiveness of the proposed method, a linear quadratic regulator (LQR) was used as a benchmark. The study showed that the proposed eMPC can provide significantly better performance than LQR under various conditions of the system. This superior performance is especially significant in terms of the system outputs peak values reduction. Nonetheless, it was pointed out that there is a need to consider other eMPC methods that lead to further reduction of the number of critical regions and more efficient exploration of the parameter space for the stabilising control of the double inverted pendulum system.

Many studies have been conducted on the improvement of operational performance through the implementation of lean manufacturing in the agri-food industries in developed countries. However, only a few have been carried out in Morocco. This approach is not just suitable for the automotive or other specific sectors of the discrete industry; it can now be adapted to other industries, provided that the characteristics of the field of application and the selection of best practices that suit them are taken into consideration. The purpose of this study is to determine the current state of the lean principles adopted by Moroccan food companies (small, medium, and large-sized enterprises). Nine food businesses were contacted, and interviews were conducted with their quality systemsmanagers, operations managers, and chief executives using a structured questionnaire. Results reveal that companies are aware of the importance of continuous improvement tools. Moreover, they partially adopt lean practices, even if they do not call them “lean”. Such an encouraging environment, including the implementation of the quality approach and performance assessment tools (dashboard), can be a preamble to the implementation of a lean approach by these organizations. To the best of the authors’ knowledge, this study is the first to investigate the application of lean practices in Moroccan food companies.

A cada ano, diversos vegetais têm sido utilizados para a obtenção de novas farinhas, que são apresentadas como fontes alternativas de nutrientes, com baixo custo de produção, podendo ser utilizadas como matérias-primas na elaboração de diferentes produtos alimentícios. Contudo, para que as farinhas sejam utilizadas como ingredientes ou substituto destes, é necessário conhecer suas propriedades físico-químicas e tecnológicas. Talinum paniculatum é uma planta alimentícia não convencional que tem sido extensivamente investigada e proposta como matéria-prima por apresentar quantidades consideráveis de proteínas e minerais. Sendo assim, o objetivo do estudo foi avaliar as características físico-químicas e funcionais tecnológicas da farinha de folhas e caules de Talinum paniculatum (FFCTP) para o direcionamento da sua aplicação na indústria de alimentos. Análises de atividade de água (Aa), umidade, pH, acidez total titulável (ATT), cinzas, cálcio, sódio, potássio, atividade antioxidante (AA), compostos fenólicos totais, capacidade de absorção de água (CAA), capacidade de absorção de óleo (CAO), solubilidade, capacidade espumante (CE), estabilidade da espuma, atividade emulsificante (AE), estabilidade da emulsão, capacidade de formação de gel (CFG), foram realizadas na FFCTP. A FFCTP obteve as seguintes características: 0,45 (Aa); 3,54% (umidade); 6,74 (pH); 0,57% de ácido cítrico (ATT); 18,58% (cinzas); 9,70 mg.100g-1(cálcio); 891,67 mg.100g-1(sódio); 5658,33 mg.100g-1(potássio); 0,50 μM Trolox mL-1 (AA); 238,82 mg GAE/100g (compostos fenólicos totais); 379,2% (CAA); 170,1% (CAO); 63,6% (solubilidade); 10,0% (CE); 93,2% (estabilidade da espuma); 55,0% (AE); 100,0% (estabilidade da emulsão); 2% (CFG). Concluiu-se que a FFCTP apresentou-se como ingrediente potencial para o enriquecimento e uso na formulação de alimentos.

Um ecossistema de inovação de sucesso necessita conter várias características, estratégias e questões culturais, usando todo o seu arcabouço desenvolvimentista para impactar o Sistema Local de Inovação ao qual está inserido. Esse artigo teve como objetivo realizar um levantamento de informações para compreensão dos Ecossistemas de Inovação de parte do Nordeste do Brasil e, a partir do entendimento, compreender a lógica desses ecossistemas para propor mecanismos que possam agilizar o processo desenvolvimentista. O método utilizado foi o levantamento de referencial teórico sobre a temática, de forma descritiva e qualitativa. Os resultados sugerem que o estado de Pernambuco, apesar de possuir um ecossistema mais sólido, necessita trabalhar o eixo cultural na questão abertura de novas estratégias que não sejam apenas de empreendedores Pernambucanos. Alagoas e Sergipe ainda amargam a falta de muitas das características que são necessárias para se ter um Ecossistema sólido e que possa impactar, positivamente, o Sistema Local de Inovação Alagoano e Sergipano.

Diante do aumento gradativo de concorrentes na advocacia, empreender se torna uma atitude primordial para a atuação nessa seara profissional. Portanto, o presente artigo, por meio de uma revisão bibliográfica, aponta estratégias que advogados podem adotar no exercício da profissão, tendo como base inovações, sejam elas de processo, de serviço ou de marketing, conforme classificação apontada no Manual de Oslo. A partir dessa propositura observa-se que, além do conhecimento jurídico, é importante que o profissional do direito saiba operar ferramentas de gestão, bem como ter noções gerais sobre a execução de estratégias de negócio, sem perder de vistas as virtudes peculiares à advocacia. Isso, pois, os recursos tecnológicos serão meios para que o advogado potencialize sua atuação, assim como oferecem uma melhor sistematização de informações que o auxilia na tomada de decisões jurídicas.

Injection characteristics play an important role in the emission and overall thermal efficiency of an engine. Several methods have been proposed for analyzing different fuel injection characteristics. This study focused on the interferometric laser imaging for droplet sizing (ILIDS) technique to investigate the effects of droplet size and velocity under different conditions of water-glycerin mixtures. These effects were evaluated using intermittent spray flows in both ambient and pressurized constant volume spray chamber conditions. The initial results were compared to those reported by previous studies and used to determine the Sauter mean diameter (SMD), arithmetic mean diameter (AMD), droplet velocity, and probability density function of the spray droplet size. SMD and AMD tended to decrease as the plate temperature, injection pressure, and viscosity were increased at specific observation areas. The average velocity of the droplet increased with higher plate temperature and injection pressure at specific observation areas. The distribution of the smaller droplet increased with higher plate temperature and injection pressure. For the water-glycerin mixture, as the glycerin ratio increased, more viscous droplets were created. This was followed in higher nozzle shear force at the outlet of the fuel injector, which decreased the particle size and generated more atomized fuel sprays. This result can enable the reduction in hydrocarbon and carbon monoxide emissions from internal combustion engines.

The aim of this research is to stabilize the indoor relative humidity and temperature for the poultry house system. The control of these parameters appears as a big challenge due to the mutual interaction existing between the variables affecting the climate livestock building. To achieve this purpose, a developed independent PID controller based on Pareto optimality is proposed in conjunction with a multi-criterion genetic algorithm (MOGA). The broiler house model is decomposed into two independent single input single output (SISO) model using a static output feedback technique (SOF). Then, a multi-criterion genetic algorithm based on Pareto optimality is used to separately design the optimal parameters of the PID controller. The effectiveness of the developed controller is tested very successfully trough numerical simulations and comparison with the Ant Colony Optimization (ACO) and Ziegler Nichols (ZN) method.

China Geodetic Coordinate System 2000 (CGCS2000), as the formal national coordinate reference frame, has been used for 20 years. The coordinates of all Global Navigation Satellite System (GNSS) stations in China need referring to this system. To this end, the first step is to align the coordinates of all stations, usually included in a regional GNSS network, with a given International Terrestrial Reference Frame (ITRF), then these coordinates are corrected to the CGCS2000 in consideration of plate movement. For a better alignment result, regional control stations are needed and their coordinates were estimated from the combination of constraint-free normal equation systems provided by several International GNSS Service (IGS) analysis centers. The effect in using these refined coordinates, which determine a regional coordinate datum, on the alignment result should be evaluated by the coordinate corrections of the regional control stations to the regional coordinate datum, i.e. smaller corrections mean better alignments of the two associated frames. The test results show that the refined coordinates are more accurate than the ones calculated from the station's velocity, and are well aligned with the ITRF2005. Moreover, for obtaining the coordinates of GNSS stations in an updated CGCS2000 frame, a gridded linear velocity field based on the estimated velocities at 1025 CGCS2000 stations was generated for mainland China using the optimal interpolation method, the inverse distance weighting, which is selected from five interpolation methods. The overall precisions of the constructed velocity field at all stations in the East (E) and, North (N) directions are 0.78 mm/a and 0.95 mm/a, respectively. For evaluating the accuracy of the updated CGCS2000 frame, monthly solutions for the coordinates of some CGCS2000 CORS stations in the ITRF2014 during the period from 2000.0 to 2018 were obtained and the Root Mean Square (RMS) of the differences between the coordinates corrected to the CGCS2000 and the known coordinates at these stations are about 2–3 cm.

In the universities, the teaching around the distribution of plants is usually done in a theoretical way and with little space to carry out practices. For this, the opportunity to create a "serious game" or "playful activity" is recognized, which, under the constructivist paradigm applied to education, allows people to appropriate the knowledge necessary to apply the Systematic Layout Planning method for plant design of production. After an in-depth investigation of the method and each stage that it is composed of, the construction of an activity that effectively poses a problem to be solved is reached, with which is hoped to provide participants with the tools to guide them in each step of Systematic Layout Planning application.

No presente trabalho, comprovou-se um crescente interesse mundial pelos biossensores voltados ao monitoramento de pesticidas. No entanto, percebeu-se que ainda existe um vasto campo de conhecimento a ser explorado na área de biossensoreamento, e esforços nesse sentido precisam ser envidados, tendo em vista que respostas rápidas no monitoramento levam a imediatas tomadas de decisão, no caso de contaminação ambiental, de alimentos ou de fármacos.

Enzimas são catalisadores biológicos responsáveis pela condução de reações bioquímicas fundamentais ao metabolismo e equilíbrio homeostático de células eucariontes e procariontes. Há uma demanda crescente de catalisadores biológicos em detrimento a catalisadores químicos, para utilização em processos de produção industrial, dado o alto grau de especificidade, melhor rendimento da reação e baixo custo final e também por sua baixa toxicidade. O objetivo deste estudo foi realizar uma busca direcionada de produção de hidrolases – amilases, proteases, lipases e celulases, por isolados microbianos de ambientes aquáticos do entorno da Província Petrolífera de Coari – AM. Foram empregados meios de cultivo contendo substratos específicos que estimularam a expressão das enzimas – alvo. Os resultados foram obtidos mediante leitura dos halos de degradação em torno das colônias microbianas crescidas em placas. Os Índices Enzimáticos (IE) foram estabelecidos pela medida do diâmetro médio do halo de degradação dividido pelo diâmetro médio da colônia microbiana. Do total de 39 isolados microbianos, bactérias e leveduras, obteve-se em percentuais, para atividade lipolítica, 61,53%, com IE máximo entre 2,0 e 6,98; para atividade amilolítica, 64,10% com IE máximo entre 2,0 e 2,5; atividade enzimática para celulase em 35,89% dos isolados, com IE entre 2,0 e 3,5; e finalmente, atividade de protease foi observada em 46,15% dos isolados, apresentando IE máximo entre 2,0 e 8,15. Os resultados obtidos foram bastante satisfatórios com destaque para as lipases e proteases, encorajando análises futuras visando sua utilização em processos industriais.

It is important to develop a suitable model to find the suitable design of inverter based on a required specification that needed to calculate the number of units per day requested by the house holders or companies. The present study deals with the required design using a developed Adaptive Neuro-Fuzzy Inference System (ANFIS) method and based on the calculated results the curve fitting is applied to form the suitable formula. The model is formulated as a function of number of units per day for the Gulf Cooperation Council (GCC) region. In general, the GCC region has high-energy consumption influenced by several factors. Therefore, the solar energy is helping to reduce the use of gas or other fuels to generate power. This means that the obtained results will encourage the GCC through the energy field development and setting the future for it to increase the use of solar energy production. The novelty of the present study is to avoid an increase in generation capacity using the gas to produce the electricity. In addition, it will help the GCC countries to avoid load shedding and meet the energy demands in different sectors. Furthermore, the developed model will help the economic development of the GCC countries. These results reduce capital investment, limiting the equipment installed and the expected load needed in the region.

Accurate sand flow rate measurement is needed to minimize the side effects of sand production in gas fields. There are concerns about the accuracy of sand flow measurement using the sand measuring devices available on the market. In this paper, ultrasonic sensors and discrete wavelet transform signal analysis method is used to measure the sand flow rate. It is found that the strength of the discrete wavelet coefficients in the frequency range of 15–62 kHz has a linear relationship with sand flow rate. This finding provides a new methodology to accurately measure sand flow rate. The proposed method does not need fluid velocity as a prerequisite for sand rate measurement, so it greatly simplifies the system design when flow meters are not used for fluid velocity measurement. Also, this method has a much simpler calibration procedure compared to that of the sand detectors commonly used in the industry.

Business systems will experience new data-driven models for their performance evaluation in the coming years, especially systems with stochastic characteristics. This development will benefit experts in energy management because more problems will be solved using machine learning algorithms - such as artificial neural networks (ANN). This research develops a machine-learning model for electricity sales using a single hidden layer ANN model. The developed model consists of six input parameters, including the number of renewable energy systems and households. This research used principal component analysis (PCA) algorithm to reduce the inputs to three parameters to improve the model performance. A TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) method was used to select the most suitable predictive models between SVR (support vector regression) and ANN. Data sets from a community in Lagos, Nigeria, were used to test the developed model performance. This research observed that a SVR model with a linear function performed better than an SVR model with a radial basis function or polynomial kernel. On the other hand, an ANN with 15 neurons outperformed ANN models with fewer nodes. The selected ANN model training and testing mean square errors are 0.00007 and 0.00028, respectively. This research recommends PCA for input parameters selection during electricity sales prediction based on the developed sales model performance.

An IGBT/MOSFET driver circuit works at a low voltage, between 5-15 V of its gate voltage to drive power converter switching devices that work at higher voltages. If there is no isolation between the driver and power converter circuits, any damage that may occur to the power converter circuit at high voltage will damage the driver circuit as well. This paper presents a design of an isolated IGBT/MOSFET driver circuit for an interleaved DC/DC boost converter using a TL494 IC to generate the required pulses for the converter’s circuit. Isolation is done using optocouplers. An IC IR2117 driver is also used to produce smooth rise and fall times for the pulses for each IGBT. The designed driver circuit is modelled using a co-simulation employing Multisim and LabVIEW software and then implemented experimentally with the help of a NI PCI-DAQ 6259. A P-I controller is implemented to regulate the output voltage of the boost converter, as well at the desired set point.

Landfill liners are underlying materials with low permeability whose main function is to mitigate the infiltration of toxic contents into ground water lying beneath. Landfill liners are primarily made of bentonite clay. Bentonite has a very low hydraulic conductivity, that might not be readily accessible, unlike kaolin which is found to have a lower hydraulic conductivity compared to that of bentonite and can be extensively obtained from numerous different sources. Explored, for the purposes of the present research paper, were various ratios of bentonite and kaolin and their hydraulic conductivity, in particular ratios of 90:10 kaolin to bentonite, 80:20 kaolin to bentonite, 70:30 kaolin to bentonite, 60:40 kaolin to bentonite and 50:50 kaolin to bentonite in an effort to achieve an acceptable barrier suitable as a liner / where tap water and ammonium solution were used as permeants. It was concluded that the ratios not lower than 20% bentonite (80:20, 70:30, 60:40 and 50:50) all had their hydraulic conductivity value reduced compared to the 100% kaolin.

The present paper focuses primarily on the agrobiological and technological characteristics of the pink local vinous varieties Pamid and Muscat red. Muscat red is a late ripening vinous variety, and variety Pamid is a medium ripening vinous variety with possibility for consumption in fresh condition as well since its pellicle and seeds are not felt, and the titrated acidity is low. Variety Muscat red belongs to the most cold-resistant local varieties. Variety Pamid has increased root phylloxera resistance, on account of which it can be cultivated on its own roots without grafting in sandy soils.

The article presents the results of studies of energy, environmental and fuel efficiency indicators of a passenger car with a gasoline injection system. The engine is equipped with a device additionally supplying liquefied petroleum gas (LPG) and it has an ignition timing variator (ITV). As a result of research, an improvement in the fuel efficiency of a car in thermal equivalent was found when the engine was running on LPG and a slight increase in energy performance was observed. Emissions of pollutants with exhaust gases change in different ways: emissions of carbon monoxide practically do not change, emissions of hydrocarbons and nitrogen oxides are growing, carbon dioxide emissions from LPG operation are reduced, socio-economic damage when the engine is running on LPG is also reduced.

This project was aimed at modelling the stress and deformation profile of a 6061-T6 aluminium suspension upright of a formula society of automotive engineers style vehicle with a double wishbone suspension under the loading conditions of a 1.5G corner. With these results, it would need to be determined whether the design is fit for use. Using remote displacement boundary conditions for the upper and lower wishbone connections and the control arm connection with a remote force at the centre of the wheel patch acting on the bearing surfaces the maximum stress, overall stress profile and maximum deformation of the upright was calculated. These results after, undertaking a verification and validation study, were a maximum equivalent von-Mises stress of 87.358MPa and a maximum bearing surface deflection of 0.21 mm. The maximum von-Mises stress calculated was less than the fatigue limit of 90MPa signalling infinite life and also less than the yield stress of 240MPa signalling a safe design. Verification and validation techniques were used to ensure the final result was accurate and reflected the real – life system. Structural error was used to verify the results where it was found that maximum structural error in the upright was 0.052mJ and at the location of maximum stress was between 0.0058-1.0782e-8 mJ. Validation of the model was achieved by comparing the reaction forces calculated in ANSYS to theoretical values and was found that the magnitudes were within 2.5% of the theoretical values, thus the model was considered valid.

Introduction. Rational recycling of agricultural machinery, which has reached the end of its service life, is an urgent problem of the modern agro-industrial complex. In this regard, using the physical model for recycling agricultural machinery, reached its service life, is a solution to the problem of resource recycling. Materials and Methods. The paired linear regression analysis method was used to conduct statistical research of experimental data and develop a regression model. The authors calculated the recyclability rate values for the entire agricultural machinery nomenclature and its average value through using regression equation. Results. Based on the analysis of indicators for technical condition of being recycled products, it was established that for developing a conceptual model of agricultural machinery recycling, it is preferable to use four main groups of indicators: technical condition, material capacity, manufacturability, and safety of components. The proposed group of indicators determines the possibility of recycling the machinery units. The results of researching the influence of indicators of design complexity, technical performance, condition, nomenclature and quantitative composition of agricultural machinery on the recyclability are presented. Discussion and Conclusion. According to the research results, a conceptual physical model for recyclability of agricultural machinery was developed that allows planning more effectively measures for recycling various types of agricultural machinery when conducting a comparative analysis of the entire nomenclature composition. The adopted restrictions allow estimating the technical condition and recyclability of agricultural machinery using the conceptual physical model of recyclability. The relationships between the storage time, complexity of technical performance, material capacity, quantitative composition (volume of recycling) and recyclability rate of agricultural machinery are revealed.

Introduction. Currently, in various technology areas, bronze, cast iron and other antifriction metals are replaced by polymer composites, which extend significantly service life of tribocoupling. An advanced antifriction polymer is ultra-high-molecular-weight polyethylene. The study deals with determining the optimal specific energy consumption for the mechanical activation of the polymer dry mixed powders and nanomodifiers in the planetary ball mill Pulverisette 7, which ensure the best complex of physico-mechanical and rheological properties of nanocomposites. Materials and Methods. In this work, we used GUR 4120 Ticona ultra-high-molecular-weight polyethylene with a molecular weight of 5 million, a Tuball Matrix Beta concentrate of activated carbon nanotubes at a concentration of 0.1%, calculated with reference to carbon nanotubes, and hydrophobic nanocrystalline silicon dioxide with a dispersion of 20 nm at the same concentration. Mechanical co-activation of polymer powders and nanomodifiers, when varying the specific energy consumption, was carried out in the planetary ball mill Pulverisette 7. The production of films from powders, for studying the elastic-strength and rheological characteristics of nanocomposites, was carried out with the use of the hydraulic press Gibitre. Tests were carried out respectively on the tensile testing machine UAI-7000 M and the rheometer Haake MARS III. Results. It has been established that the best physico-mechanical and rheological properties of nanocomposites are with specific energy consumption for mechanical activation of 3,000‒3,200 J/g that allows us to consider them optimal. The mechanical activation of ultra-high molecular weight polyethylene powder, reducing slightly the elasticity modulus and tensile strength of thermally pressed samples, does not affect the dynamic viscosity of melts at an energy consumption of 650‒4,550 J/g. Discussion and Conclusion. The use of carbon nanotubes and nanocrystalline silicon dioxide at a concentration of 0.1% can significantly improve the physical-mechanical and rheological properties of the polymer with energy costs of 3,000‒3,200 J/g for mechanical activation in planetary ball mills. Nanocrystalline silicon dioxide is a more effective modifier that can be explained by its better dispersion in the polymer matrix due to the lower tendency of nanoparticles to agglomerate.

Introduction. The earth cutter resource depends on the characteristics of the materials they are made from. In particular, the important parameters that directly affect the tillage tool parts efficiency and durability are the values and ratios of the coefficients of relative wear resistance of the two-layer parts materials, as a rule of the hardened deposited layer and the base material (steel). It is established that the characteristics of the relative wear resistance of the materials for earth cutter parts vary depending on the treated soil properties. The objectives of the study are to consider the influence of soil conditions on the values of the relative wear resistance coefficients of two-layer earth cutter part materials and to carry out a comparative assessment of their resource and use efficiency. Materials and Methods. The authors gave a generalized dependence of the wear proportionality to the existing specific pressures values. The characteristics of soil abrasion were given. The scientific substantiation of the changes in the characteristics of the materials wear resistance at various values of specific pressures was given. Results. The results of the operational resource tests and the studies of two-layer and monometallic earth cutters are presented. The influences of the values of the operating specific pressures on the coefficients of the relative wear resistance of the materials for the tillage machine parts are determined. Discussion and Conclusion. The authors have found out that the coefficients of relative wear resistance of materials are not constant, but vary depending on the current surface specific pressures. The correlation of the specific pressure values with the parameters of the tillage operation, in particular with the furrow slice hardness was established. It has been found that while increasing the cultivated soil hardness, the coefficients of various materials relative wear resistance get closer to each other. The difference varies from 1.80 to1.85 times.

Introduction. The necessity to classify the state of rail lines affected by significant damaging factors on the sensitive element of the information sensor providing the assurance of classification quality with the required length of the rail lines of the control section forms the task of creating a classifier with extended functionality. Extending the functionality is possible using multidimensional state images with a set of informative features and training procedures for classification models. Using the classical classification principle with a single model leads to an excessive complication of the classification algorithm with low accuracy due to inaccurate solution of the system of conditional equations with multidimensional approximation by Hermite polynomials. Materials and Methods. The principles of reducing the dimension of the features space, various procedures for trainable classifier of state of rail lines with multidimensional patterns, the selection of decisive classification rules with a hierarchical grouping of classes, and the formation of a set of models of varying degrees of complexity trained to solve an incompatible system of equations are considered to solve the problem. There were obtained various degrees of complexity used in the adaptive algorithm for classifying the rail lines states using Hermite polynomials as models. Results. The article presents the results of developing 57 classifier models using Hermite polynomials with features of 2, 3, 4, 5, 6 arguments. As an example, the procedure of developing models with 2–6 features is shown. The research results showed that with an increase in the number of features, the quality of classification improves, as when dividing the state space into several classes. Discussion and Conclusion. The results of the studies confirm the feasibility of the principle of classification of rail line states by a set of classification models, and an algorithm of recursively increasing the classification complexity using a model of increased complexity. The criterion for presenting a new, more complex model is the mismatch between the results of the class calculation by the i-th model and the real class in which the rail line is located at the moment in time.

Introduction. Spring wheat yield depends largely on the wheat variety, seed quality, cultivation technology, and agro-climatic factors. It has been found that the separation of wheat seeds into fractions makes it possible to improve the quality of post-harvest processing, adjust the quality of grain depending on the intended use, and the sowing of the wheat grains divided into fractions allows increasing productivity. The aim of the article is to explore the membrane potential on the shells of wheat grains divided into fractions according to their aerodynamic properties and to compare certain membrane potential features with aerodynamic properties of these grains and the yields of selected varieties. Materials and Methods. The seeds, divided into fractions, have different sowing qualities. Biologically deficient seeds have poor germination index. The study have found that the division of seeds into fractions contributes to increasing yields, but the main indicators of quality are still germination and viability, for this reason an approach has been developed to determine the quality of wheat seeds divided into fractions. Results. This article studies the change in membrane potential of wheat seeds, divided into fractions according to their aerodynamic properties. The article presents the results of testing a new clamping electrode with a smooth surface to measure the membrane potential of wheat gains. To study the effect of the wheat variety, the aerodynamic properties of grains and yield on changes in membrane potential, we analyzed three indices: the resting potential level, time of variable potential rise to the maximum value and variable potential maximum value. Discussion and Conclusion. New informative indicators have been determined because of the two-way analysis of variance of the research results. These indicators reliably reflect the aerodynamic properties of seeds and can be used to predict yields. The use of the obtained results will allow agricultural enterprises and farms to determine the quality of post-harvest processing of wheat seeds, adjust the quality depending on the intended use, and evaluate and forecast the productivity of seeds.

Introduction. Improving the efficiency of agricultural operations and off-road logistics require new highly efficient non-road machinery with low pressure on road surface. The versatility of the use of this machinery imposes additional requirements on its design, including those related to road traffic safety on public roads. Changes in brake design are required to ensure safe braking performance when larger diameter wheels are used for the reason that to produce standard braking force according to the technical regulations for the safety of wheeled vehicles, requires more braking torque when using larger diameter wheels. Materials and Methods. The article proposes a model for calculating the braking parameters of transport and technological agricultural machines equipped with ultra-low pressure wheels. The model differs from those used earlier in that its output parameter is not the braking efficiency, but the time difference between the front and rear axle locks. Results. Fulfilling the condition of the front axle advance locking ensures the stability of the tractor motion during emergency braking that has a positive effect on road traffic safety. The results of the study suggest that to ensure the safe motion of the machines equipped with ultra-low pressure tires on public roads, it is necessary that the ratio of the distance from the center of mass to the front axle is at least not less than the distance from the center of mass to the road surface. Discussion and Conclusion. The proposed mathematical model has shown its adequacy. The obtained mathematical dependencies allow us to justify different technical solutions for ensuring safe road movement of transport and technological agricultural machines equipped with ultra-low pressure tires. Thus, the maximum permissible height of the center of mass can be assumed to be equal to 90% of the distance from the location of the center of mass of an agricultural transport and technological machine to its front (controlled) axis.

O objetivo deste artigo é investigar como são elaboradas as interações discursivas no Twitter a partir das hashtags #SennaSempre e #MeuAyrton na rememoração da data de 25 anos de morte de Ayrton Senna. Um dos mais importantes atletas da história esportiva do Brasil, o ex-piloto segue sendo um dos esportistas mais lembrados pelas novas gerações na internet após 25 anos de sua morte. Desta forma, este trabalho também analisa como o Twitter é utilizado para a manutenção da imagem do ídolo para essas novas gerações e como usuários desta rede social digital específica se apropriam das estratégias elaboradas oficialmente para manutenção da memória de Senna.