Dissertações em Engenharia Industrial (Mestrado) - PPGEI/ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/10051

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Agora exibindo 1 - 20 de 21

Acesso aberto (Open Access)
Avaliação da resistência elétrica e mecânica da liga de alumínio série 6101 modificada com 0,16%Nb
(Universidade Federal do Pará, 2021-06-28) ALMEIDA, Denyson Teixeira; QUARESMA, José Maria do Vale; http://lattes.cnpq.br/7443111804471290
The requirement for better materials for electrical cables has demanded the need of new, stronger and better conductivity aluminum metal composites. 6xxx series alloys, more specifically 6101 and 6201, have been combined with various chemical elements, heat treated and artificially aged to improve mechanical strength and conductivity. Brazil is the largest producer, exporter and holder of the worldwide niobium deposits. Thus, this metal has a high potential as a very promising alloying element for the target material of this study, when it combined with other metals, makes the material superconducting, has a medium grain refinement effect, an aggregating action to improvement of mechanical strength. In this study it will be proposed to add [0.16]%Nb to the Al-0,05%Cu-[0,24-0,28]%Fe-0,5%Si-0,6%Mg, casting in “U” metal shell evaluating the behavior of the heat resistance according to COPEL protocol (Companhia Paranaense de Energia Elétrica), mechanical, electrical resistance and microstructural characterization.
Acesso aberto (Open Access)
Remoção de Ni2+ de soluções aquosas utilizando o talo do cacho do açaí (Euterpe oleracea) como Biossorvente
(Universidade Federal do Pará, 2021-06-30) GESTER, Nayara Matos Lima; SIQUEIRA, Joana Luíza Pires; http://lattes.cnpq.br/4650162959340860
This work used as biosorbent the stem of the açaí bunch (Euterpe oleracea) – TCA – in natura for phytoremediation of the heavy metal Ni2+ from synthetic solutions. The material was characterized using Fourier Transform (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) techniques. The result of the infrared analysis revealed the presence of hydroxylic and carboxylic functional main groups fundamental in the biosorption process. The SEM analysis showed a material with a rough and porous structure with a visible variety of pore sizes and the EDS semi-quantitatively detected the presence of elements such as C, O and Ca, characteristic of lignocellulosic materials, in addition to the presence of Ni2+ after the process of adsorption. The adsorption behavior of Ni2+ ion in aqueous solution by the açaí bunch stem (ACT) was carried out in batch and investigated influences such as concentration, dosage, granulometry, contact time and pH. At a concentration of 25 mg.L-1 and pH between 6 and 7 TCA showed removal efficiency above 80%. Langmuir, Freundlich and Dubinin-Radushkevich models were applied to describe the equilibrium isotherms using linear regression analysis. The adsorption kinetic mechanism was better represented by the pseudo-second order kinetics. Monolayer adsorption according to the Langmuir model better described the biosorption process in TCA with a correlation coefficient (R2) close to 1 and a maximum adsorption capacity of 8.62 mg.g-1. The process kinetics showed a better fit to the pseudo-second order model, indicating chemisorption, with R2 close to 1, adsorption capacity (qe) = 6.60 mg.g-1 and adsorption rate constant (K2) = 0.082 g.mg-1.min-1. The TCA in natura presented satisfactory results for the treatment of wastewater, a fact that reinforces its environmental proposal.
Acesso aberto (Open Access)
Gestão de processos: propostas de melhoria de desempenho da Divisão de Compras do Instituto de Tecnologia da Universidade Federal do Pará
(Universidade Federal do Pará, 2022-12-16) PAES, Luana Pinon de Carvalho; CORREA, Alessandro de Castro; http://lattes.cnpq.br/6408989265441974
This work aims to propose performance improvements alternatives for the Purchasing Division of the Institute of Technology (ITEC) of the Federal University of Pará (UFPA). It is a case study, characterized as a quantitative and qualitative research of descriptive character. Data collection was carried out through process mapping; interviews with a script of open questions; questionnaires and document analysis. The results reveal that the initial purchase request phase is the one that presents the most difficulties, in view of the rework verified at this time, when budgets with irregular companies before federal agencies are delivered to the purchasing sector. It was also noted the difficulty of applicants in going to the Purchasing Division to deliver documents, especially after the New Corona Virus Pandemic. Among the suggestions for improvement proposed, the following stand out: i) a pilot project for purchase requests via the UFPA Customer Service System (SAGITTA), in which applicants would have access to all information regarding purchases, in addition to not having to go to the purchasing sector to deliver the documentation, which would allow a great reduction of errors and rework and, consequently, faster processing of processes; and ii) the request that the plaintiffs consult the negative certificates of the companies before delivering the budgets, in order to avoid the delivery of invalid documentation. It can be concluded through the analysis of the results that, after applying the proposed improvements, there was a reduction in the cycle time of the ITEC purchase processes through the reduction of errors and rework. The reduction of the cycle time will provide ITEC with efficiency gains, which will be able to manage its purchase requests more effectively, with a reduction in resource losses at the end of each year. It is worth highlighting the importance of the impact that this work can bring not only to the Institute of Technology, with a view to better use of resources, but also to other UFPA Institutes or other Universities, which can use the aforementioned proposals.
Acesso aberto (Open Access)
Avaliação da resistência ao desgaste do aço hadfield e ferro fundido branco alto cromo em ensaio pino-disco com fragmentação de abrasivo para aplicações na mineração
(Universidade Federal do Pará, 2024-11-12) SILVA, Rute Nara de Jesus Farias da; MACHADO, Paulo Cordeiro; http://lattes.cnpq.br/0133330144786049
Mining, as an industry with processes that include excavation, crushing, and grinding, faces high levels of wear, resulting in component failures, increased energy consumption, and operational costs. Studies indicate that global energy consumption in mining activities is significant, with a large portion used to overcome friction and replace worn parts. The present work investigates the efficiency of different materials, such as Hadfield steel with 15% Mn (Mn15) and high-chromium white cast iron (HCWCI), in resisting abrasive wear, as well as parameterizing the test equipment for the two materials. The Pin-on-Disc Abrasive Wear Test with Abrasive Fragmentation (PDFA) was used to simulate and evaluate the abrasive wear resistance of these materials. The research compares the wear micromechanisms observed in the PDFA test with those found in the jaw crusher test, aiming to identify less complex and more cost-effective ways to evaluate the studied materials. This emphasizes the importance of tests that closely replicate real operational conditions, optimizing material selection while reducing costs, energy consumption, and CO2 emissions in mining. The characterization of the worn samples was performed using optical microscopy and scanning electron microscopy (SEM) in SE, BSE, and EDS modes. The wear rates were 0.0006 g/min for HCWCI and 0.0021 g/min for Mn15 steel. Additionally, similar micromechanisms, such as microgrooving, microcutting, and microcracking, were observed on the surfaces of both materials, comparable to those identified in fixed jaw samples tested under jaw crusher conditions.
Acesso aberto (Open Access)
Gestão de materiais: sistemática para o estoque e consumo no Instituto de Tecnologia da UFPA
(Universidade Federal do Pará, 2022-09-02) TERRA, Rosiane dos Santos; OLIVEIRA, Salete Souza de; http://lattes.cnpq.br/6003210915464722
The management of consumables is part of the strategies of public agencies, the warehouse needs special attention, as it is a differential in the institution, when managed. In this way, the present work aims to elaborate a systematic for the stock and consumption of the Institute of Technology (ITEC) of UFPA through the evaluationand update of the layout of the warehouse sector, implementation of a resource for requests and consultations of materials, through of SAGITTA, which is a service system made available to the university community with several institutional services and implementation of the WAREHOUSE module in the Integrated System of Heritage, Administration and Contracts (SIPAC). Based on the results, the gains obtained with the request time for the acquisition of a material, reduction of waste, correct information about the existence of material resources and the organization of the warehouse spaceare shown.
Acesso aberto (Open Access)
Melhoria do processo de aquisição de equipamentos médicos assistenciais em hospital público
(Universidade Federal do Pará, 2024-12-19) PEREIRA, Guilherme Figueiredo; VIEIRA JÚNIOR, Petrônio; http://lattes.cnpq.br/1958791286192330
Hospitals aim to promote the health of the population through an extensive and complex range of services. Even though the main activity of these institutions is caring for patients, there are a series of managerial and administrative activities necessary to continue providing care to the population, among which the purchasing process stands out. The objective of this work is to propose improvements in the process of acquiring medical-care equipment using Lean Healthcare concepts. To this end, the purchasing process in a public hospital was specifically analyzed, through the analysis of the history of purchasing processes in the electronic auction modality of the price registration system from 2021 to 2022, in addition to documentary and field research , where the inefficiency of this process in the institution was observed. Interviews were carried out with the main people involved in the sectors most active in the acquisition processes. A series of improvement opportunities were observed at several different points in the process, which were adjusted in search of greater efficiency. Based on the information collected, an action plan was prepared to apply improvements, including the development of a SOP to assist in standardizing the acquisition planning process. As a result, there was an improvement in the efficiency of the medical equipment purchasing process at the institution studied by more than 30% in the approval rate of items in the EMH acquisition auction.
Acesso aberto (Open Access)
Avaliação da influência das águas de poço e industrial tratada na corrosão do cobre
(Universidade Federal do Pará, 2021-02-04) LIMA, Andel Denilson Matos; CARDOSO FILHO, José Carlos de Araújo; http://lattes.cnpq.br/7033790503322903
Efficient corrosion monitoring prevents, in an industry, unplanned downtime for corrective maintenance to exchange parts, pipes, materials, components and equipment made of copper that have contact with raw or treated water and that suffer wear and tear over time. This work monitored through the exposure of well water and treated a cosmetics industry, located in the State of Pará, the level of corrosivity when in contact with corrosion coupons (proof bodies) made of copper. The method of analysis consisted of immersing these coupons in well water and industrial water for 7, 14, 21 and 28 days. In each period, the coupons were removed clean and taken to mass loss tests, corrosion rate, corrosion potential and polarization curves. In addition to physicalchemical and microbiological analyzes of water samples for the calculation of stability, which shows whether the trend is stable, corrosive or fouling. The results showed that well water has low corrosivity and industrial water has moderate corrosivity, even receiving chemical treatment for pH correction and microbiological control. The loss of mass and the corrosion rate of the copper coupon were greater for industrial water and the polarization curves and corrosion potential showed that industrial water has a high degree of corrosion compared to well water.
Acesso aberto (Open Access)
Análise de um vaso de pressão pós-incidente
(Universidade Federal do Pará, 2021-12-13) RODRIGUES, Igor Florentino; DIAS, Carmen Gilda Barroso Tavares; http://lattes.cnpq.br/2113791118142177
Composite materials have numerous applications in the most varied areas of engineering as offshore, oil and gas industry, marine industries, aeronautics, and automaker. Used because they bring high rigidity and specific resistance, due to the advantages of being resistant to corrosion and having structural flexibility. The work is focused on fiberglass composites with epoxy matrix (FG) and no high-density polyethylene (HDPE) a decade after the incident. The approach was based in two stage, first on an investigation that took place on board of a semisubmersible drilling rig that operates offshore with a drilling capacity of 7500 meters in depth and a water depth of 2500 meters. a high pressure line that is connected to CAPV (composite air pressure vessel) that is part of to the high pressure system of the CMC (Crown mounted compensator). In a second stage, was took samples from CAPV to be analyzed, where impact tests (Charpy) were performed according to ASTM D6110-10 standard, flexion tests according to ASTM D790-17 standard, differential scanning calorimetry (DSC) according to ASTM D3418-12 standard, scanning electron microscopy (SEM) and thermogravimetric to have a more detailed study on the composite materials that made up those vessels, which are PEHD and FG with matrix epoxy. Showed the results of the investigation and finish the work with material analyses assays even after 10 years of manufacture and complications during the use of the vessels.
Acesso aberto (Open Access)
Influência da taxa de resfriamento nas tensões residuais de solda por centelhamento de trilho ferroviário
(Universidade Federal do Pará, 2021-12-22) BARILE, Iury Klay Peres; COSTA, Ednelson da Silva; http://lattes.cnpq.br/0045584096510351; HTTPS://ORCID.ORG/0000-0002-7290-3810; MACHADO, Paulo Cordeiro; http://lattes.cnpq.br/0133330144786049; https://orcid.org/0000-0003-4375-6812
The process of manufacturing and welding in rail induces residual stresses that can act in a deleterious way to the structural integrity of this component, especially in cases where the tractive stresses, can favor the nucleation and propagation of cracks, may cause premature rail failure. The objective this work is evaluate the residual stresses of rails welded by flash butt welding (FBW) with and without heat treatment post welding with forced air cooling. The techniques measurement of residual stress ultrasound using shear waves in the metal base and hole Drilling in the center of the weld and in the zone thermally affected (HAZ). The techniques presented similar results to those found in the literature, for the head, tensile stresses were found in the base metal region, and compressive stresses in the HAZ and center of the weld. In the web, tensile stresses were found at the HAZ and the center of the weld.
Acesso aberto (Open Access)
Projeto, montagem e testes de fonte Cockcroft - Walton para Electrospinning
(Universidade Federal do Pará, 2022-06-06) ARAÚJO FILHO, Paulo Sérgio Alves de; VIEIRA JÚNIOR, Petrônio; http://lattes.cnpq.br/1958791286192330; DIAS, Carmen Gilda Barroso Tavares; http://lattes.cnpq.br/2113791118142177
Electrospinning is a way of spinning using an electric field, the wire formed has a nanometric diameter and is used in biomaterials, pharmaceuticals, electronics, in the area of semiconductors and energy generation. During electrospinning, the solution leaves a starter vessel and reaches a screen through the force of the electric field. The method fits according to the purpose of the experiment. For each objective there are a variety of polymers, solvents, the latter defining the operating ranges for: field strength, voltage and operating distance. A source was designed and assembled using the Cockcroft multiplier. For the design of the circuit, design and simulations were carried out. For validation, electrospinning was performed using the source.
Acesso aberto (Open Access)
Caracterização mecânica e análise fractográfica de compósitos poliméricos com fibras naturais do epicarpo do coco babaçu (Orbignya Speciosa)
(Universidade Federal do Pará, 2022-12-14) SANTOS, Hudson Carlos Melo dos; GOMES, Laércio Gouvêa; http://lattes.cnpq.br/5907468972539239; https://orcid.org/0000-0002-8474-0748
The pressure exerted on natural resources, arising from the exponential growth of world demand, leads human activity to an unprecedented scenario. Researchers have been demonstrating numerous efforts for sustainable solutions, in this scenario there is a continuous growth in the development of composite materials with vegetable fibers. In this work, pure orthophthalic polyester matrix materials and composite materials with plant fibers from the babassu coconut epicarp were produced. The composites were manufactured manually using silicone molds. The fibers characterized according to their morphology, through scanning electron microscopy (SEM), were randomly inserted with mass fractions set at 3% and 5%, length varying between 10 mm and 20 mm. The composites produced were analyzed for their mechanical properties, through tensile and flexural tests according to ASTM D 638 and ASTM D 790 standards, and fractographic analysis of the fracture surface through scanning electron microscopy (SEM). The morphological analysis of the surface of the fibers showed its roughness and characteristics present in vegetable fibers. For composites with 3% of fibers, a tensile strength of 20.03 MPa was obtained, while for composites with 5% of fibers, the result was 14.16 MPa. of 32.34 MPa for the composites with 3% of fibers and 37.01 MPa for the composites with 5% of fibers, in both properties (tensile strength and flexural strength) there was a reduction of the same when compared to the matrix material pure. With regard to the modulus of elasticity, the composites had an increase in this mechanical property when compared to the pure matrix, confirming that the increase in the stiffness of the material is due to the increase in the fiber fraction, with the best results obtained in composites with 5 % of fibers, 0.486 GPa in tensile tests and 27.10 GPa in bending tests. The fractographic analyzes of the fracture surfaces showed satisfactory results regarding the identification of failure mechanisms and characteristics present in the composites, such as the presence of air bubbles, voids and the phenomenon of fibers pulled out of the matrix (pull out), indicating low adhesion at the interface matrix/fiber.
Acesso aberto (Open Access)
Caracterização mecânica e metalúrgica de parafusos da classe 10.9, utilizados na fixação da suspensão dianteira de veículos CAT793D, aplicando tratamento termoquímico de cementação
(Universidade Federal do Pará, 2022-08-31) RABELO JÚNIOR, Fábio Alves; CARDOSO FILHO, José Carlos de Araújo; QUARESMA, José Maria do Vale; http://lattes.cnpq.br/7443111804471290
When a structural component of a large piece of equipment fails, catastrophic consequences can occur, generating highly measurable economic losses, because a failure leads to an interruption of an entire production line and damage to the workflow, which can cause delays and increased maintenance costs, whether preventive or corrective. In addition, serious risk conditions affect the loss of life in cases of catastrophic accidents, where they are widely reported by the media and strongly influence an organization's conduct. The objective of this work is to carry out the mechanical and metallurgical characterization of screws of class 10.9, applying the Thermochemical Treatment of Cementation, evaluating the influence of this mechanical resistance. These components include the Caterpillar model 793D “Off-Highway” truck suspension system that carries heavy iron ore loads in the Ferro-Carajás complex, in the state of Pará. Thermo-chemical treatments and mechanical tests were carried out and Tensile Stress. Fractographic and Microstructural analyzes were performed using Scanning Electron Microscopy - SEM, in addition to Optical Microscopy.
Acesso aberto (Open Access)
Emulação de carga para geração de energia elétrica usando inversor
(Universidade Federal do Pará, 2022-06-30) LOPES, Marcos Andrey da Silva; VIEIRA JÚNIOR, Petrônio; http://lattes.cnpq.br/1958791286192330
This paper aims to emulate variable load on a simulation bench for wind and hydraulic generation using an inverter connected to a fixed load consisting of a bank of resistances and inductances. From the modeling performed on the hydraulic and wind turbines, it is possible to reproduce the effects caused by variations in the dynamics of each generation, such as the variation in wind, for wind, or the flow of water in a distributor, for hydraulic . The generation simulation bench is composed of a separate excitation machine (DC motor), simulating the primary source, driven by a converter, which is coupled to a generator, this one feeding the inverter, which is responsible for the interface with the load. From this coupling of the motor-generator set, it is possible, through the inverter, to carry out the load variation, in order to simulate different load conditions in the generation. The inverter is used as a load variation strategy for dynamic response studies of simulated generation systems, voltage and frequency regulation, harmonic analysis in the system, among many situations. Through this set, it was possible to vary the generator armature current by properly configuring the inverter parameters. To complete the study, the look at table method is proposed for the proper selection of inverter parameters for load variation.
Acesso aberto (Open Access)
Análise do estado plano de tensões em chapas de aço ASTM A131 por métodos ultrassônicos
(Universidade Federal do Pará, 2023-08-17) ALBUQUERQUE, Lucas Gabriel de Sousa; MACHADO, Paulo Cordeiro; http://lattes.cnpq.br/0133330144786049; https://orcid.org/0000-0003-4375-6812
Residual stresses affect the mechanical component in the same way that external stresses do. These stresses usually arise in the manufacturing process. By knowing the residual stresses, mainly the tensile stresses, present in a component or those that may be generated by some manufacturing process, it is possible to take actions to avoid or minimize their effects, thus extending the component's useful life. Thus, residual stress will always be a demand to be studied, both by academia and by the metal-mechanic industry. Therefore, the objective of this work was to determine the plane state of residual stresses in ASTM A131 steel plates by combined shear and compressive ultrasonic wave methods. A TIG welding torch was used to induce residual stresses in the plates by the high thermal gradient. The specimens were xed by supports to avoid deformation, thus preserving the residual stresses. Three different methods were applied, named, in this paper, as: Hirao I; Clark; and Hirao II. The major difference between them is related to the preferred direction of wave propagation. Stresses in different directions from the anisotropy axis can change this direction. Consequently, the angle between the anisotropy and the preferential direction of propagation of the ultrasonic wave (φ) is changed. To measure the propagation time of the ultrasonic waves, a software was developed for the acquisition of the ultrasonic response signals and another one for the data processing.To end the preferential angle of wave propagation, a support was made by 3D printing, which allowed the transducer to be moved using a stepper motor. In all three methods, very high tensile stresses were observed near the melt zone, which decreased rapidly as the distance from this region increased. In addition, the values of φ were lower in the center line than in the lateral lines, indicating variation in residual stress levels as function of distance from the constraints.
Acesso aberto (Open Access)
Protótipo de um secador de grãos rotativo compacto com sistema fotovoltaico
(Universidade Federal do Pará, 2023-08-06) RODRIGUES, Benedito de Jesus da Silva; DIAS, Carmen Gilda Barroso Tavares; http://lattes.cnpq.br/2113791118142177 País de Nacionalidade Brasil
The industrial bioeconomy of açaí, a fruit native to the Amazon, produces food with antioxidant phenolic compounds and lipids. Fractions of the pulping by-product are used to generate bioenergy and are being researched as biopolymers, filler for making furniture and architectural materials. With this in mind, two rotary grain dryers were designed: the first is a commercial model (capable of drying 14 kg of açaí kernels) and the second is a compact model (capable of drying 1.0 kg of material). Due to the practicality of its use in the laboratory, the compact model was selected for manufacture. This prototype consists of: a micro motor (with adjustable torque and frequency, 40W of electrical power and bivolt 127/220VAC), which drives a rotating drum (measuring 24cm in diameter by 24cm in length) at a rotation speed of 57.6rpm, an air heating system (consisting of: air confinement chamber, thermal heating module and temperature controller). The equipment is autonomous for forestry use, with a photovoltaic electricity generation system (configuration: a 60Ah battery, a 540WP monocrystalline photovoltaic module, a 40A PWM charge regulator and a 1000W DC/AC inverter). In the laboratory experiments, 1 kg of açaí kernels were dried (for a period of two hours and forty-three minutes), after which the following fractions were obtained: 5% fiber, 1% insoluble particulate matter from the mesocarp and 63% endocarp. The compact rotary grain dryer is a versatile technology that could be used in biomaterials research in the future, contributing to the region's sustainability and macro-economy.
Acesso aberto (Open Access)
Desenvolvimento de monitoração na geração fotovoltaica em comunidades isoladas
(Universidade Federal do Pará, 2023-04-26) GONÇALVES, Francisco Reginaldo Conceição; VIEIRA JÚNIOR, Petronio; http://lattes.cnpq.br/1958791286192330
Nowadays, photovoltaic solar energy represents a significant portion of all electricity consumed in the world. It is crucial to develop tools for monitoring the solar system that aim to maintain generation productivity and mitigate security risks. This work presents a proposal for a development platform for monitoring photovoltaic generation for isolated communities, consisting of generation simulation, data transmission, database and supervisory system. The mathematical model used in the simulation is based on a system being implemented by the Automation Technology Group (GTA) at the Electrical Engineering Laboratory of the UFPA University Campus in Belém. Data are obtained by simulation and are transmitted to the cloud through a NodeMCU ESP8266 microcontroller. The computer, in addition to performing the simulation to obtain photovoltaic generation data, also accesses the clouds, acquiring data for the supervisory. The supervisory system is developed on the Internet of Things (IoT) platforms Thingspeak and Cloud Database, allowing the detection and diagnosis of failures. Measures such as solar radiation intensity, temperature, humidity, electric voltage and electric current are analyzed in order to diagnose faults. Through cloud computing, data is stored and made available in real time, with ample capacity and mobility, allowing remote monitoring of the system. Database tools with dedicated interfaces are used, as well as platforms focused on the internet of things. The photovoltaic generation is being implemented in an experimental bench, and the parameters of the simulated model have the same amplitudes as the real model, which has 1 solar panel with a maximum power of 130W, a maximum voltage of 17.6V and a maximum current of 7.39A. The perspective of this work is to improve the supply of electricity to isolated communities through remote monitoring of the generation system, with social and economic impact.
Acesso aberto (Open Access)
Implantação da manutenção centrada na confiabilidade (MCC) em um alto forno de usina siderúrgica
(Universidade Federal do Pará, 2023-07-05) BASTOS, Filipe Carneiro; FUJIYAMA, Roberto Tetsuo; http://lattes.cnpq.br/3165747089941318; https://orcid.org/0000-0002-2738-6666
The technological development has provided many changes in the industrial process, and has led to the need for improvement of maintenance in view of the importance of operational availability for the companies' results. In this perspective, the Reliability Centered Maintenance has been widely used in the industrial sector, aiming improvements in the process and ensuring the reliability of the assets. To apply the method, the 5 steps for implementation were followed, in the following order: (i) Selection and training of a multidisciplinary team, (ii) Selection of the system/process and information collection, (iii) Reliability analysis of the critical equipments, (iv) Analysis of the functions and functional failures, (v) Application of FMEA (Failure Mode and Effects Analysis) and (vi) Determination of the new maintenance plans. Finally, a comparison was made between the maintenance plans before and after the MCC implementation and the gains obtained by reducing the number of corrective maintenances in a certain period of analysis were presented.
Acesso aberto (Open Access)
Obtenção de filmes de colágeno de peixe para biomaterais: peixes da amazônia (Heros Severus e Cichla Temensis) e tilápia do nilo (Oreochromis Niloticus)
(Universidade Federal do Pará, 2023-10-27) COELHO, Katherine Elice Paes Leão; LAMEIRA, Aladim Gomes; http://lattes.cnpq.br/7739057853603135; DIAS, Carmen Gilda Barroso Tavares; http://lattes.cnpq.br/2113791118142177
The Collagen films derived from fish skin have been gaining prominence in tissue engineering, with emphasis on the large number of research on the properties of those obtained from Nile Tilapia - TN (Oreochromis niloticus).Parallel to this; the Amazon Basin has numerous species of fish, which have not yet been deeply addressed in the field of bioprospecting. In this sense, this paper sought to prepare and analyze films derived from the skins of Amazonian fish, such as Peacock Bass - TA (Cichla Temensis) and Banded Cichlid - AS (Heros Severus), comparing them with that of the African fish TN. From the results obtained, it was verified that TN was the one with the highest collagen yield. The proteins were extracted and purified to prepare aqueous solutions with polyvinyl alcohol. The films obtained by solvent evaporation showed the following traction resistance results: 327 MPa for TN; 299 MPa for AS, and 228 MPa for TA. Through scanning electron microscopy, it was possible to note that the greatest porosity was present in TN films, which received a coating of spheres and nanofibers deposited at a distance of 3 cm under tension of 6.3 KW generated in a COCKCROFT – WALTON source. Therefore, it was found that, although the TA and AS polymers showed good results, the films made from Tilapia were the ones that best corroborated those made from biomaterials for dental use. Finally, it is believed that those using Amazonian fish made it possible to reproduce methods already vehemently applied in the literature and could eventually supply the needs of market.
Acesso aberto (Open Access)
Efeito da temperatura, tempo e taxa de resfriamento na formação do eutetóide divorciado em soldas de trilhos de aço perlítico
(Universidade Federal do Pará, 2021-06-01) BARBOSA, Matheus dos Santos; MACHADO, Paulo Cordeiro; http://lattes.cnpq.br/0133330144786049
The hardness reduction that occurs at the end of the Heat Affected Zone (HAZ) of welded joints of railway is generated through of the Divorced Eutectoid formation (DE). This transformation happens in the weld during the cooling of the austenite when there is presence of undissolved carbides, which, in turn, act as preexisting cores for the formation of this microstructure, forming a combination of spheroidized cementite + ferrite. In order to understand this microstructural transformation, samples of premium and superpremium rails were tested by dilatometry, with a full factorial Design Of Experiments (DOE) that evaluated the effects of variables temperature, holding time and cooling rate; and their interactions. The samples after thermal cycling were characterized by microhardness test and scanning electron microscopy analysis. The results showed that the highest DE fractions were obtained at higher temperatures (750 °C) and with higher equivalent carbon. However, by increasing the cooling rate, from 1.5 to 9 °C/s, resulted in a reduction of the DE fraction of 49% for the premium rail at 750 °C and 75% for the superpremium rail at 740 °C. Regarding hardness, the behavior was inversely proportional, where the increase in the cooling rate provided an increase in the hardness of the rails (about 21%), in addition, the samples simulated at 740 and 750 °C and cooled to 1.5° C/s showed hardness similar to that was found in the region of lower hardness of rails welded by Flash Butt Weld (FBW). The factors that had the greatest effect on DE formation, in increasing order, were temperature, equivalent carbon and cooling rate.
Acesso aberto (Open Access)
Análise de viabilidade econômica da implantação de uma indústria beneficiadora de açaí no município de Abaetetuba/PA
(Universidade Federal do Pará, 2021-10-13) PRAXEDES, Adalberto Malato; CORREA, Alessandro de Castro; http://lattes.cnpq.br/6408989265441974
This work analyzed the economic feasibility of implementing an açaí processing industry in the city of Abaetetuba/PA. A structured interview was carried out with the interested investor group in order to understand their objectives and expectations, as well as the project's premises. The average cost of açaí in the harvest and in the off-season was estimated through a survey in the domestic market. The evaluation was carried out based on the discounted cash flow method, the Net Present Value, the Internal Rate of Return and Payback as feasibility indicators. For the Minimum Attractiveness Rate, the cost of capital was adopted based on the beta calculated by the Capital Asset Pricing Model (CAPM) from daily observations of share prices of companies in the Brazilian food sector from 04/01/2018 to 04/01 /2021 and the Selic rate as a risk-free rate. The Monte Carlo simulation technique was used to analyze the uncertainty associated with different scenarios resulting from variations in demand, in the cost of goods produced in the harvest, in the cost of goods produced in the off-season and in the sale price. The results indicated that the project is viable and suggest that there is a 62.82% chance of generating positive results.