The Journal of Engineering and Exact Sciences

Development of a decision-making system based on the mandala of water and agricultural sustainability

Thu, 11 Jan 2024 00:00:00 -0300

This article aimed to develop an innovative decision support tool for sustainable water and agricultural management in river basins, using the Mandala of Water and Agricultural Sustainability. The system was built with technologies such as Django and Plotly, allowing a facilitating interface for water resources management with inclusive and participatory decision-making. A free web application was created, paving the way for user testing, updates based on results and final launch of the tool. It is believed that this will promote greater accessibility to information and involvement of social actors in water and agricultural management, resulting in more integrated and sustainable decisions.

Removal of methyl orange and bromocresol green dyes from aqueous solutions through adsorption on activated carbon

Wed, 31 Jan 2024 00:00:00 -0300

O presente estudo descreve o processo de adsorção dos corantes sintéticos laranja de metila (AM) e verde de bromocresol (VB) em meio aquoso, utilizando carvão ativado (CA) como material adsorvente. Foram avaliados diferentes parâmetros como tempo de contato, dosagem do adsorvente e concentração inicial de adsorbato. A cinética de adsorção foi avaliada utilizando os modelos de pseudo-primeira ordem e pseudo-segunda ordem, sendo os dados cinéticos melhor ajustados ao primeiro modelo para VB e ao segundo modelo para AM. O tempo de equilíbrio de adsorção foi alcançado em 1850 e 1440 min para AM e VB, respectivamente, com suas capacidades máximas de adsorção (Qt) sendo 2,98 e 2,46 mg g ^-1 nas condições estudadas. Os resultados demonstraram que a remoção dos corantes AM e VB em meio aquoso utilizando CA é favorável, uma vez que este material apresentou taxas máximas de adsorção de 95% para AM e 75% para VB.

The effect of incorporation of calcined sediments and perlite as partial cement replacement on mortars behavior

Mokhtar Achour, Nadia Belas, Rachid Hadj Sadok — Sun, 31 Mar 2024 00:00:00 -0300

The accumulation of sediments in varied dams built in Algeria denotes a vital problem that requires immediate attention and action from the authorities and managers of the National Agency for Dams and Transfers (ANBT). More than that, various research studies on sediments have revealed that subjecting them to heat treatment can exploit these sediments as a viable substitute for some of the cement used to produce cementitious materials. Combining the different types and quantities of natural Perlite pozzolan can achieve many benefits, including reduced consumption, minimized heat generation, improved workability, reduced permeability, and increased strength. This study aims to explore the potential of using dredged sediments from Chorfa II dams and perlite from Hammam Boughrara (located in western Algeria) as substitutes for cement in mortar analysis. A thorough examination of calcined sediments and perlite revealed the feasibility of partial cement replacement. Research has mainly focused on evaluating the properties of mortars in fresh and hardened states.

Chemical and physical modification of corn starch and application in cupuassu and babassu dairy dessert

Sun, 24 Mar 2024 00:00:00 -0300

Corn starch is not suitable for products that require refrigerated storage, due to the high syneresis. To overcome this and other limitations, chemical and physical modifications can be used. Considering the application of Amazonian fruits in a dairy dessert as a way of adding value to the products, this work aimed to modify corn starch with chemical and physical treatments, evaluate its physical-chemical characteristics, apply the modified starch in babassu and cupuassu dairy dessert and evaluate their physical-chemical and sensory properties. The starches were chemically modified by hydrogen peroxide and sodium hypochlorite at 1, 2 and 3% and physically by HMT with 15, 20 and 25% of humidity and annealing at 50, 55 and 60 °C. The modification by hydrogen peroxide caused a considerable decrease in the release of water, with syneresis after 7 days of 0%, so this starch was used in the dairy dessert. The syneresis analysis of the desserts confirmed that the hydrogen peroxide modification was capable of considerably reducing the syneresis of dairy products. The tasters did not feel any significant difference between the samples with native and modified starch in the sensory tests. The mixed dairy dessert received good acceptance and purchase intention.

Structural appraisal of baja prototype using resistive strain gauges and linear potentiometer

Wed, 24 Jan 2024 00:00:00 -0300

Every machine or structural component undergoes a certain elastic deformation when exposed to some type of load or force. Furthermore, when it comes to the design and validation of components, a structural analysis plays a fundamental role, given the need to guarantee the integrity of the designed parts. To achieve this, reliable data is essential so that the entire process can be carried out in a coherent manner, based on engineering criteria. Therefore, the present study seeks to acquire dynamic or static loads and forces, which are present in main and critical components in a BAJA-type prototype, from the KomiKeto Baja Team - UFSJ, aiming to acquire data for the use of boundary conditions in numerical simulations, in addition to dynamic capture of loading cycles for subsequent fatigue analysis.

Computational modeling of the uterus simulating the biomechanical behavior of pregnancy with intrauterine pressure application

Fri, 05 Jan 2024 00:00:00 -0300

Premature birth, a severe public health issue, affects one in every ten babies worldwide. Pathological uterine distension can impose tension on the uterine wall, capable of triggering contractions and, thus, leading to premature birth. Despite the increasing use of computational models in pregnancy-related studies, a lack of experimental data and ethical concerns limit research on the mechanical properties of the uterus during gestation. This work presents a computational study of uterine growth during the second half of pregnancy. The geometric model represents the uterine body and was derived from truncated ellipsoids. The constitutive model used is anisotropic, and the tissue is considered incompressible. In this approach, the simulation is conducted by applying intrauterine pressure and simplified boundary conditions. The results obtained in the simulations reveal the evolution and deformation of the uterus with increasing intrauterine pressure.

Numerical simulation with hyperelastic constitutive model for high-performance multifilaments used in offshore mooring ropes

Thu, 25 Jan 2024 00:00:00 -0300

The present study addresses the numerical simulation of the stress-strain behavior of synthetic multifilaments subjected to creep, fatigue cycles, and rupture. Understanding the mechanical properties of these materials is essential for various industrial applications, including technical textiles, ropes, cables, and composite materials. In this study, advanced simulation methods are employed using concepts from continuum mechanics and solid mechanics, coupled with a hyperelastic model. The simulated materials are high modulus polyester and polyethylene fibers for use in multifilament structures. Experimental tests were conducted to validate the simulation, and the simulation results were compared to the reference data to assess the quality of the numerical simulation. As a result, the numerical modeling shows capable of representing the constitutive behavior under creep, fatigue, and rupture solicitations. There was a certain difficulty in representing the behavior when many inelastic components were present in the fibers. Additionally, changes in curvature and concavity pose challenges that could potentially be addressed by other energy models integrated into the proposed code. These findings have significant implications in engineering sectors.

Modeling and Linearization of a 1-GDL Helicopter System for Digital Controller Design: PID and via State Feedback

Sun, 24 Mar 2024 00:00:00 -0300

This work intent to develop the modeling and linearization of a helicopter system with one degree of freedom (1-GDL), using MATLAB and Simulink software. Then, two digital controllers were designed, using the PID approach and state feedback, to evaluate robustness and rejection of disturbances through performance indices and design specifications. Accordingly with the results obtained, it was found that the compensator via state feedback showed better performance in the angular position stabilization process.

Evaluation of energy efficiency in sugar cane bass burning processes in sugar and alcoholic plants

Lucas Devetak Casado, Andréa Teresa Riccio Barbosa — Thu, 11 Jan 2024 00:00:00 -0300

This work addresses the global need to develop new energy sources, in addition to seeking to improve existing sources due to the growing global energy demand, arising from factors such as population growth, consumerism and economic competitiveness. In Brazil, a third of the energy consumed comes from oil and its derivatives, despite the energy matrix being heterogeneous, with emphasis on energy from biomass, mainly from sugarcane bagasse, which represents 77% of national production. Ethanol, currently one of the main fuels in the country, is also largely responsible for this variety in the energy matrix. It emerged as an alternative to fossil fuels during the oil crises, in addition to bringing with it the cogeneration of sugarcane bagasse, which became a sustainable solution to the excess of this residue in sugar and alcohol plants. Therefore, it is important to look for ways to increase energy efficiency in this sector in order to increase profitability and reduce the environmental impact of processes.

Guide for authors: jCEC Template 2024

Tue, 26 Mar 2024 00:00:00 -0300

This document gives formatting instructions for authors preparing articles for publication in the jCEC journal. The authors must follow the instructions given in the document for the articles to be published. You can use this document as both an instruction set and as a template into which you can type your own text. Abstract should be no longer than 1000 characters including spaces (or from 200 to 300 words). It gives a brief summary of the content of the main objective, the methods, the results obtained and major conclusions. Translation of the abstract to an appropriate language must be provided here. Please choose either Portuguese, French or Spanish, and adapt your list of keywords accordingly.

Evaluation of solid-liquid extraction of levodopa from mucuna seeds using different solvents

Fri, 09 Feb 2024 00:00:00 -0300

Levodopa is the main drug currently used to treat Parkinson's disease. This amino acid, found in the mucuna seed, is a direct precursor to dopamine, which acts to reduce and control of disease’s symptoms. The commercially available levodopa is produced synthetically, however, due to the relevance of the topic, studies have been carried out to find alternatives for extracting this compound from natural sources, making the process more economical and sustainable with the use of alternative solvents. In this study, the objective was to characterize the seeds of gray mucuna (Mucuna cinerea) and evaluate the solid-liquid extraction yield of levodopa, using different solvents (benzoic acid, succinic acid, choline chloride, ethanol, PEG 4000 and water). To evaluate which solvents and factors most influenced the extraction yield, a factorial design (2³) was carried out. The factors were temperature, extraction time and the ratio between solid and solvent. Composition analysis showed that mucuna is rich in proteins with 26.49% and carbohydrates with 50.63%, has 10.16% minerals, 4.08% lipids and 8.64% moisture. Levodopa was quantified using high-performance liquid chromatography, with an aqueous mixture of water and ethanol 50% m/m being the most suitable solvent for extraction, achieving a yield of 14.14%.

A brief functional investigation via Sobolev spaces to analyze the behavior of Oseen flow in external domains

Fri, 19 Jan 2024 00:00:00 -0300

This work serves as an introductory exploration of Oseen flow, a mathematical and physical framework for modeling fluid dynamics, with a specific focus on viscous substances like liquids or gases. The presented theorem and its associated lemmas are an extension of the foundational theory of potential flow, which is conventionally applied to inviscid fluids. The primary goal in investigating Oseen flow within external domains is to elucidate the influence of viscous effects on flow patterns beyond solid structures. As a result, we prove the existence of generalized solutions when is a three-dimensional (3D) domain in Stokes problem.

Effect of W/C ratio on the rheological and physico-mechanical behavior of high performance concrete formulated with natural pozzolana

Ismahene Guemidi, Hosni Abderrahmane Taleb, Yazid Abdelaziz — Thu, 11 Jan 2024 00:00:00 -0300

High-performance concretes (HPC) are known for their high mechanical strength (> 60 MPa) and dense microtexture, which hinders the penetration of aggressive agents. In this study, we conducted experiments to create cost-effective HPC using locally available materials in the Bechar region. The second objective is to explore how different water-to-cement ratios (0.3, 0.35, and 0.4) affect the rheological and physico-mechanical properties (workability, porosity, compressive and flexural strength, water absorption, and density) of HPC made with natural pozzolana from the Boukais region. Additionally, we examined the impact of using natural pozzolana as a partial substitute in Portland cement (10% and 20%) on the physico-mechanical behavior of HPC.