CAD e engenharia reversa como ferramentas de auxílio na fabricação de cartuchos para próteses ortopédicas

The manufacturing of above and below-knee prosthesis starts by taking surfac measurements of the patient s residual limb. This demands the making of a cartridg with appropriate fitting and customized to the profile of each patient. The traditiona process in public hospitals in Brazil begins with the completion of a record file (according to law nº388, of July 28, 1999 by the ministry of the health) for obtaining o the prosthesis, where it is identified the amputation level, equipment type, fitting type material, measures etc. Nowadays, that work is covered by the Brazilian Nationa Health Service (SUS) and is accomplished in a manual way being used commo measuring tapes characterizing a quite rudimentary, handmade work and without an accuracy.In this dissertation it is presented the development of a computer integrate tool that it include CAD theory, for visualization of both above and below-knee prosthesis in 3D (i.e. OrtoCAD), as well as, the design and the construction a low cos electro-mechanic 3D scanner (EMS). This apparatus is capable to automatically obtain geometric information of the stump or of the healthy leg while ensuring smalle uncertainty degree for all measurements. The methodology is based on reverse engineering concepts so that the EMS output is fed into the above mentioned academi CAD software in charge of the 3D computer graphics reconstruction of the residualimb s negative plaster cast or even the healthy leg s mirror image. The obtained results demonstrate that the proposed model is valid, because it allows the structura analysis to be performed based on the requested loads, boundary conditions, material chosen and wall thickness. Furthermore it allows the manufacturing of a prosthesis cartridge meeting high accuracy engineering patterns with consequent improvement in the quality of the overall production process

Desgaste de polímeros estruturais de engenharia em contato de deslizamento com cilindro metálico

Present work proposed to map and features the wear mechanisms of structural polymers of engineering derived of the sliding contact with a metallic cylindrical spindle submitted to eccentricity due to fluctuations in it is mass and geometric centers. For this it was projected and makes an experimental apparatus from balancing machine where the cylindrical counterbody was supported in two bearings and the polymeric coupon was situated in a holder with freedom of displacement along counterbody. Thus, the experimental tests were standardized using two position of the two bearings (Fixed or Free) and seven different positions along the counterbody, that permit print different conditions to the stiffness from system. Others parameters as applied normal load, sliding velocity and distance were fixed. In this investigation it was used as coupon two structural polymers of wide quotidian use, PTFE (polytetrafluroethylene) and PEEK (poly-ether-ether-ketone) and the AISI 4140 alloy steel as counterbody. Polymeric materials were characterized by thermal analysis (thermogravimetric, differential scanning calorimetry and dynamic-mechanical), hardness and rays-X diffractometry. While the metallic material was submitted at hardness, mechanical resistance tests and metallographic analysis. During the tribological tests were recorded the heating response with thermometers, yonder overall velocity vibration (VGV) and the acceleration using accelerometers. After tests the wear surface of the coupons were analyzed using a Scanning Electronic Microscopy (SEM) to morphological analysis and spectroscopy EDS to microanalysis. Moreover the roughness of the counterbody was characterized before and after the tribological tests. It was observed that the tribological response of the polymers were different in function of their distinct molecular structure. It were identified the predominant wear mechanisms in each polymer. The VGV of the PTFE was smaller than PEEK, in the condition of minimum stiffness, in function of the higher loss coefficient of that polymer. Wear rate of the PTFE was more of a magnitude order higher than PEEK. With the results was possible developed a correlation between the wear rate and parameter (E/ρ)1/2 (Young modulus, E, density, ρ), proportional at longitudinal elastic wave velocity in the material.

A engenharia simultânea e o perfil da indústria de confecção da grande Natal/RN utilizando as ferramentas CAD/PDM e ERP

This work presents the research carried through in the industrial segment of confection of clothes of the Great Natal whose objective is to show the profile, enterprise and technological management as also the use of simultaneous engineering in the development of products. The research approaches two studies. The first one presents the current picture of the companies, synthesized through twelve variable. As, through fifteen variable it shows to the level of use of Simultaneous Engineering in the Development of Products and its amplitude in relation to the Integrated Management using tools CAD, PDM and ERP (Computer Aided Design, Product Management Date, Enterprise Resource Planning). The integration of these systems acts aiming the reduction of the cost and the development time of products. The reached results indicate that simultaneous engineering is a competitive advantage and becomes possible: to reduce the life cycle of the product, to rationalize the resources, to incorporate one high standard of the quality to the process and product as well as to personalize the product to take care of the global market. It is important to note that this work also is considered to contribute for the better understanding of the real companies situation of confection located at the Great Natal and its role in the economy of the State of the Rio Grande do Norte

Análise de tensões integrada a sistema de engenharia reversa para projeto e confecção de próteses

This work consists of the conception, developing and implementation of a Computational Routine CAE which has algorithms suitable for the tension and deformation analysis. The system was integrated to an academic software named as OrtoCAD. The expansion algorithms for the interface CAE genereated by this work were developed in FORTRAN with the objective of increase the applications of two former works of PPGEM-UFRN: project and fabrication of a Electromechanincal reader and Software OrtoCAD. The software OrtoCAD is an interface that, orinally, includes the visualization of prothetic cartridges from the data obtained from a electromechanical reader (LEM). The LEM is basically a tridimensional scanner based on reverse engineering. First, the geometry of a residual limb (i.e., the remaining part of an amputee leg wherein the prothesis is fixed) is obtained from the data generated by LEM by the use of Reverse Engineering concepts. The proposed core FEA uses the Shell's Theory where a 2D surface is generated from a 3D piece form OrtoCAD. The shell's analysis program uses the well-known Finite Elements Method to describe the geometry and the behavior of the material. The program is based square-based Lagragean elements of nine nodes and displacement field of higher order to a better description of the tension field in the thickness. As a result, the new FEA routine provide excellent advantages by providing new features to OrtoCAD: independency of high cost commercial softwares; new routines were added to the OrtoCAD library for more realistic problems by using criteria of fault engineering of composites materials; enhanced the performance of the FEA analysis by using a specific grid element for a higher number of nodes; and finally, it has the advantage of open-source project and offering customized intrinsic versatility and wide possibilities of editing and/or optimization that may be necessary in the future

Simulação numérica da convecção mista em cavidade preenchida com meio poroso heterogêneo e homogêneo

In this work is presented mixed convection heat transfer inside a lid-driven cavity heated from below and filled with heterogeneous and homogeneous porous medium. In the heterogeneous approach, the solid domain is represented by heat conductive equally spaced blocks; the fluid phase surrounds the blocks being limited by the cavity walls. The homogeneous or pore-continuum approach is characterized by the cavity porosity and permeability. Generalized mass, momentum and energy conservation equations are obtained in dimensionless form to represent both the continuum and the pore-continuum models. The numerical solution is obtained via the finite volume method. QUICK interpolation scheme is set for numerical treatment of the advection terms and SIMPLE algorithm is applied for pressure-velocity coupling. Aiming the laminar regime, the flow parameters are kept in the range of 102≤Re≤103 and 103≤Ra≤106 for both the heterogeneous and homogeneous approaches. In the tested configurations for the continuous model, 9, 16, 36, and 64 blocks are considered for each combination of Re and Ra being the microscopic porosity set as constant φ=0,64 . For the pore-continuum model the Darcy number (Da) is set according to the number of blocks in the heterogeneous cavity and the φ. Numerical results of the comparative study between the microscopic and macroscopic approaches are presented. As a result, average Nusselt number equations for the continuum and the pore continuum models as a function of Ra and Re are obtained.

O Litoral e a metrópole dinâmica imobiliária, turismo e expansão urbana na região metropolitana de Natal-RN

The metropolitan regions of Northeast Brazil are being gradually included in a scenario of international investments, which are motivated by the restructuring of both touristic and real-estate sectors. The new capital, real-estate developers and space configurations that result from this process indicate the need for the creation and implementation of public tools which should, at least, allow the mitigation of the urban impacts and environmental losses resulting from this situation. The effects on landscape and on the socio-spatial configuration result from the intensification caused by the dynamism of the "real estate-tourism" sector. There is a regional integration as an expression of the urban expansion of the metropolitan area of Natal. This study investigates the uniqueness of the restructuring and territorial integration of coastal areas and the strategies of the circuit of capital accumulation formed by linking the real estate to tourism. It is intended to increase the understanding about the strategies of tourism, real estate and public policy agents involved in this territorial reconfiguration and in the fund-raising needed for the investments, to understand the existing social and environmental effects and their future trends and also to understand the forms of spatial production as results from the practices of approaching the land transformation and the tourism valorization of the landscape, in a synchronous manner, first in the Northeast region and, as a focal study, in the Metropolitan Area of Natal. Likewise, it is intended to apprehend the current processes of metropolization of the eastern coast of Rio Grande do Norte, in addition to indicate its physical-territorial transformation and the types of projects/developments promoted by the market in the recent period. Based upon analysis undertaken for the Metropolitan Region of Natal RN, this piece of work presents some considerations on possible legal instruments that can be adjusted to the municipalities which are experiencing the impact of this peculiar and recent phenomenon in the region, caused by the arrival of the real estate-touristic capital. It is also intended to point out basic proposals to the forms of public intervention, in a speculative way, starting from a Metropolitan Planning project within a medium and long term

Localização e planejamento de caminhos para um robô humanóide e um robô escravo com rodas

This work presents the localization and path planning systems for two robots: a non-instrumented humanoid and a slave wheeled robot. The localization of wheeled robot is made using odometry information and landmark detection. These informations are fused using a Extended Kalman Filter. The relative position of humanoid is acquired fusing (using another Kalman Filter) the wheeled robot pose with the characteristics of the landmark on the back of humanoid. Knowing the wheeled robot position and the humanoid relative position in relation to it, we acquired the absolute position of humanoid. The path planning system was developed to provide the cooperative movement of the two robots,incorporating the visibility restrictions of the robotic system

Desenvolvimento de um Sistema de Visão Global para uma Frota de Mini-Robôs Móveis

Navigation based on visual feedback for robots, working in a closed environment, can be obtained settling a camera in each robot (local vision system). However, this solution requests a camera and capacity of local processing for each robot. When possible, a global vision system is a cheapest solution for this problem. In this case, one or a little amount of cameras, covering all the workspace, can be shared by the entire team of robots, saving the cost of a great amount of cameras and the associated processing hardware needed in a local vision system. This work presents the implementation and experimental results of a global vision system for mobile mini-robots, using robot soccer as test platform. The proposed vision system consists of a camera, a frame grabber and a computer (PC) for image processing. The PC is responsible for the team motion control, based on the visual feedback, sending commands to the robots through a radio link. In order for the system to be able to unequivocally recognize each robot, each one has a label on its top, consisting of two colored circles. Image processing algorithms were developed for the eficient computation, in real time, of all objects position (robot and ball) and orientation (robot). A great problem found was to label the color, in real time, of each colored point of the image, in time-varying illumination conditions. To overcome this problem, an automatic camera calibration, based on clustering K-means algorithm, was implemented. This method guarantees that similar pixels will be clustered around a unique color class. The obtained experimental results shown that the position and orientation of each robot can be obtained with a precision of few millimeters. The updating of the position and orientation was attained in real time, analyzing 30 frames per second

Modelo matemático para otimização dos custos de um sistema híbrido eólico-solar : aplicação no bombeamento de petróleo

This work purposes the application of a methodology to optimize the implantation cost of an wind-solar hybrid system for oil pumping. The developed model is estimated the implantation cost of system through Multiple Linear Regression technique, on the basis of the previous knowledge of variables: necessary capacity of storage, total daily energy demand, wind power, module power and module number. These variables are gotten by means of sizing. The considered model not only can be applied to the oil pumping, but also for any other purposes of electric energy generation for conversion of solar, wind or solar-wind energy, that demand short powers. Parametric statistical T-student tests had been used to detect the significant difference in the average of total cost to being considered the diameter of the wind, F by Snedecor in the variance analysis to test if the coefficients of the considered model are significantly different of zero and test not-parametric statistical by Friedman, toverify if there is difference in the system cost, by being considered the photovoltaic module powers. In decision of hypothesis tests was considered a 5%-significant level. The configurations module powers showed significant differences in total cost of investment by considering an electrical motor of 3 HP. The configurations module powers showed significant differences in total cost of investment by considering an electrical motor of 5 HP only to wind speed of 4m/s and 6 m/s in wind of 3 m, 4m and 5 m of diameter. There was not significant difference in costs to diameters of winds of 3 m and 4m. The mathematical model and the computational program may be used to others applications which require electrical between 2.250 W and 3.750 W. A computational program was developed to assist the study of several configurations that optimizes the implantation cost of an wind-solar system through considered mathematical model

Simulação da transferência de calor em amostras aquecidas por plasma

The processing of materials through plasma has been growing enough in the last times in several technological applications, more specifically in surfaces treatment. That growth is due, mainly, to the great applicability of plasmas as energy source, where it assumes behavior thermal, chemical and/or physical. On the other hand, the multiplicity of simultaneous physical effects (thermal, chemical and physical interactions) present in plasmas increases the complexity for understanding their interaction with solids. In that sense, as an initial step for the development of that subject, the present work treats of the computational simulation of the heating and cooling processes of steel and copper samples immersed in a plasma atmosphere, by considering two experimental geometric configurations: hollow and plane cathode. In order to reach such goal, three computational models were developed in Fortran 90 language: an one-dimensional transient model (1D, t), a two-dimensional transient model (2D, t) and a two-dimensional transient model (2D, t) which take into account the presence of a sample holder in the experimental assembly. The models were developed based on the finite volume method and, for the two-dimensional configurations, the effect of hollow cathode on the sample was considered as a lateral external heat source. The main results obtained with the three computational models, as temperature distribution and thermal gradients in the samples and in the holder, were compared with those developed by the Laboratory of Plasma, LabPlasma/UFRN, and with experiments available in the literature. The behavior showed indicates the validity of the developed codes and illustrate the need of the use of such computational tool in that process type, due to the great easiness of obtaining thermal information of interest

Análise da Conformidade e Caracterização da Matéria- Prima Empregada na Fabricação de Blocos Cerâmicos na Região Metropolitana de Salvador

The potential market of the metropolitan area of Salvador accounts for the estimated consumption of roughly 800 million horizontally perforated extruded clay bricks a year. The growing demand of consumers along with the competitiveness of the structural ceramic sector has driven forward a number of recent efforts and investments towards improving the quality of structural ceramics. In this scenario, the present study focused on sampling and evaluating the conformity of 8-hole horizontally perforated extruded clay bricks manufactured by different plants (A, B and C) in the metropolitan area of Salvador. In addition, representative clay and sandy-clay materials were collected from each plant and characterized by conventional physical, chemical and mineralogical techniques. Finally, experimental compositions designated as A, B and C, according to the source, were prepared by mixing different contents of the raw materials collected in the plants, fired at different temperatures and characterized. The results revealed a series of non conformities regarding ABNT guidelines. The characterization of raw materials revealed the presence of kaolinite and ilite in concentrations ranging from 64 to 90 wt.% along with free quartz (10 - 25%). The sandy-clay samples consisted basically of kaolinite. All raw materials depicted low contents of organics, amorphous constituents, alkaline oxides and feldspar. An analysis of the firing behavior of all different ceramic compositions revealed that the linear contraction of composition A was rather significant considering the temperature range evaluated, and it justifies the significant dimensional non conformity that was shown by bricks made with the ceramic A

Protótipo de uma unidade com tri-geração de energia para utilizações remotas: aplicação de módulo secondutivo gerador termoelétrico

The generation for termoeletricity is characterized as a solid process of conversion of thermal energy (heat) in electric without the necessity of mobile parts. Although the conversion process is of low efficiency the system presents high degree of trustworthiness and low requisite of maintenance and durability. Its principle is based on the studies of termogeneration carried through by Thomas Seebeck in 1800. The frank development of the technologies of solid state for termoeletricity generation, the necessity of the best exploitation of the energy, also with incentive the cogeneration processes, the reduction of the ambient impact allies to the development of modules semiconductors of high efficiency, converge to the use of the thermoeletric generation through components of solid state in remote applications. The work presents the development, construction and performance evaluation of an prototype, in pilot scale, for energy tri-generation aiming at application in remote areas. The unit is composed of a gas lamp as primary source of energy, a module commercial semiconductor for thermoelectric generation and a shirt for production of the luminosity. The project of the device made compatible a headstock for adaptation in the gas lamp, a hot source for adaptation of the module, an exchanger of to be used heat as cold source and to compose first stage of cogeneration, an exchanger of tubular heat to compose second stage of cogeneration, the elaboration of a converter dc-dc type push pull, adequacy of a system of acquisition of temperature. It was become fullfilled assembly of the prototype in group of benches for tests and assay in the full load condition in order to evaluate its efficiency, had been carried through energy balance of the unit. The prototype presented an electric efficiency of 0,73%, thermal of 56,55%, illumination of 1,35% and global of 58,62%. The developed prototype, as the adopted methodology of assay had also taken care of to the considered objectives, making possible the attainment of conclusive results concerning to the experiment. Optimization in the system of setting of the semicondutor module, improvement in the thermal insulation and design of the prototype and system of protection to the user are suggestions to become it a commercial product

Influência da adição de rejeitos cerâmicos nas propriedades de cerâmica vermelha da região do Recôncavo Baiano

The study of the physical and mechanic properties is an analysis of unquestioned importance on the production of the ceramic materials. In the region of the Recôncavo Baiano, there are ceramic and small brick factories, that still use rudimentary techniques, where the necessity of characterization of raw materials is denounced by the quality of the final product. The present work has for objective to study the behavior of the clay proceeding from the region of the Recôncavo, between the cities of Candeias and Camaçari/Ba, with addition of 5, 10 and 15% by weight of brick scraps, trying to optimize the physic and mechanical properties of the final product, aiming a better possibility of being manufactured, mechanic resistance, low linear retraction and water absorption. The brick scraps and the clay were characterized by FRX, DRX, TG, ATD and the granulometric analysis. Samples for testing where prepared by uniaxial pressing at 25Mpa, in 60x20x5mm size. The evaluated technological properties were: linear retraction, water absorption, apparent porosity and flexural strength. The samples were burned in electric oven in the temperatures of 850º, 950º and 1050ºC and compared its mechanical properties and the gresification. With addition of 15% by weight of brick scraps and burning at 900º-1000ºC the samples showed properties superior to that clay

Viabilidades térmica, econômica e de materiais de um sistema solar de aquecimento de água a baixo custo para fins residenciais

An solar alternative system for water heating is presented. Is composed for one low cost alternative collector and alternative thermal reservoir for hot water storing. The collector of the system has box confectioned in composite material and use absorption coils formed for PVC tubes. The box of hot water storage was confectioned from a plastic polyethylene drum used for storage of water and garbage, coated for a cylinder confectioned in fiber glass. The principle of functioning of the system is the same of the conventionally. Its regimen of work is the thermosiphon for a volume of 250 liters water. The main characteristic of the system in considered study is its low cost, allowing a bigger socialization of the use of solar energy. It will be demonstrated the viabilities thermal, economic and of materials of the system of considered heating, and its competitiveness in relation to the available collectors commercially. Relative aspects will be boarded also the susceptibility the thermal degradation and for UV for the PVC tubes. It will be shown that such system of alternative heating, that has as main characteristic its low cost, presents viabilities thermal, economic and of materials

Adição de geomanta e tecido não tecido de polipropileno em cimentos geopoliméricos de pega rápida

Geopolymers are cementing materials that depict a number of advantages compared to Portland cement. Contrary to the latter, geopolymers are synthesized at room temperature, thus significantly reducing the emission of CO2 to the atmosphere. Moreover, the composition and synthesis reactions can be tailored to adjust the setting time of the material as well as its compressive mechanical strength. It is then possible to produce geopolymeric cements with short setting times and high compressive strength, although relatively brittle. The objective of the present study was to produce and characterize composite materials by reinforcing fastsetting geopolymeric matrixes with polypropylene geosynthetics (geomats and geotextiles) in an attempt to improve the toughness and tensile strength of the cementing material. Geosynthetics have been increasingly used to reinforce engineering structures, providing higher strength and better toughness. In particular, polypropylene nonwoven and geomats depict other attractive properties such as low density, durability, impact absorption and resistance to abrasion. Fast-setting geopolymers were then synthesized and reinforced with polypropylene nonwoven and geomats. The mechanical strength of the materials, reinforced or not, was characterized. The results showed that relatively short setting times and adequate flowing behavior were achieved by adjusting the composition of the geopolymer. In addition, it is possible to improve the fracture resistance of geopolymeric cements by adding polypropylene geosynthetics. The best results were achieved by reinforcing geopolymer with polypropylene TNT