The oral route of drug administration is most extensively used due to the obvious ease of administration. Verapamil hydrochloride is a WHO listed phenylalkylarnine, L-type calcium channel antagonist that is mainly indicated for cardiovascular disorders such as angina pectoris, supraventricular tachycardia and hypertension. Due to its relatively short half-life of approximately 4.0 hours, the formulation of a sustained-release dosage form is useful to improve patient compliance and to achieve predictable and optimized therapeutic plasma concentrations. Direct compression and wet granulation were initially used as methods for tablet manufacture. The direct compression method of manufacture produced tablets that exhibited formulation and manufacturing difficulties. Mini-tablets containing veraparnil hydrochloride were then prepared by wet granulation using Surelease® E-7-19010.and Eudragit® NE 30D as the granulating agents after which the granules were incorporated with an hydrophilic matrix material, Carbopol® 974P NF. Granule and powder blends were evaluated using the angle of repose, loose and tapped bulk density, Can's compressibility index, Hausner's ratio and drug content. Granules with good flow properties and satisfactory compressibility were used for further studies. Tablets were subjected to thickness, diameter and weight variation tests, crushing strength, tensile strength, friability and content uniformity studies. Tablets that showed acceptable pharmaco-technical properties were selected for further analysis. Drug content uniformity and dissolution release rates were determined using a validated isocratic HPLC method. Initially, USP apparatus 1 and 3 dissolution apparatus were used to determine in-vitro drug release rates from the formulations over a 22-hour period. USP apparatus 3 was finally selected as it offers the advantages of mimicking, in part, the changes in the physicochemical environment experienced by products in the gastro-intestinal tract. Differences in release rates between the test formulations and a commercially available product, Isoptin® SR were observed at different pH's using USP apparatus 1. The release of veraparnil hydrochloride from matrix tablets was pH dependent and was markedly reduced at higher pH values. This may be due, in part, to the poor solubility of veraparnil hydrochloride at these pH values and also the possible interaction of verapamil hydrochloride with anionic polymers used in these formulations. Swelling and erosion behaviour of the tablets were evaluated and differences in behaviour were observed which may be attributed to the physico-chemical characteristics of the polymers used in this study. In-vitro dissolution profiles were characterized by the difference (j1) and similarity factor (j2) and also by a new similarity factor, Sct. In addition, the mechanism of drug release from these dosage forms was mainly evaluated using the Korsmeyer-Peppas model and the kinetics of drug release assessed using other models, including Zero order, First order, Higuchi, HixsonCrowell, Weibull and the Baker-Lonsdale model. Dissolution kinetics were best described by application of the Weibull model, and the Korsmeyer-Peppas model. The release exponent, n, confirmed that drug release from these dosage forms was due to the mixed effects of diffusion and swelling and therefore, anomalous release kinetics are predominant. In conclusion, two test batches were found to be comparable to the reference product Isoptin® SR with respect to their in-vitro release profiles.

Audiomagnetotelluric measurements with (CSAMT) and without (AMT) a controlled source were performed near Gällivare and Kiruna in Swedish Lapland in order to retrieve representative conductivity models of the subsurfaces. Magnetotelluric transfer functions were gained from processed time series’ and subsequently inverted to generate the sought models successfully. Additionally, a strike angle analysis was performed to determine the dimension of the ground structures. That information was used to justify the approaches of 1D and 2D inversions of the data sets and to judge their applicability. In Kiruna, two profiles were installed. One profile is considered to be in line with the strike direction, the other profile was oriented rather orthogonal to the strike direction. In Gällivare, only one profile was installed orthogonally with respect to the strike direction. The strike analysis showed a preferentially 2-dimensional structure for Kiruna’s parallel profile. For the orthogonal oriented profiles from Kiruna and Gällivare, the analysis revealed a 2D (with distortions) to 3D dimension of the ground structures. For the AMT method, it was possible to generate 1-dimensional and 2-dimensional models. Regarding the CSAMT data, it was only possible to generate a 1D conductivitymodel for the subsurface. Due to a significant transmitter overprint, no undistorted start model for the 2-dimensional CSAMT data inversion could be produced. The models from Kiruna had a sufficient data quality and thus resulted in reliable 2D AMT resistivity models with, locally, 2 to 3 layers. However, in combination with the 1D models for AMT and CSAMT, a 3-layer structure was predicted, where a resistive layer is covered by a thin conductive layer and underlaid by a rather conductive basement. For Gällivare’s profile, the data quality was good such that for all inversion methods good results were achieved. The predicted 2-layer models were resolved for for depths between 10m and 10,000m and coincide with the at hand geological maps and cross sections.

Magister Scientiae - MSc / The focus of this study is to synthesize a novel hinged polymer actuator. The linking molecule (hinge) is phenazine with interconnected dipyrrole units. / South Africa

Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-05-04T19:38:16Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) aline_pereira_costa.pdf: 2041406 bytes, checksum: 9995d567446721eda6ae8ff6dbdbe60c (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-05-16T16:59:24Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) aline_pereira_costa.pdf: 2041406 bytes, checksum: 9995d567446721eda6ae8ff6dbdbe60c (MD5) / Made available in DSpace on 2017-05-16T16:59:24Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) aline_pereira_costa.pdf: 2041406 bytes, checksum: 9995d567446721eda6ae8ff6dbdbe60c (MD5) Previous issue date: 2016 / Este projeto surgiu de uma defici?ncia do Departamento de Computa??o da UFVJM (Universidade Federal dos Vales do Jequitinhonha e Mucuri), em armazenar e recuperar seus of?cios. Tal Departamento possui dificuldades na organiza??o e armazenamento eficiente destes of?cios o que inviabiliza o acesso aos documentos e dispende muito tempo na localiza??o e recupera??o da informa??o. Diante disso, foi desenvolvido um Sistema de Indexa??o Autom?tica utilizando-se t?cnicas da biblioteconomia e t?cnicas computacionais que visa automatizar o processo de indexa??o de novos of?cios, otimizar a recupera??o e democratizar o acesso a informa??o. O banco de dados do Sistema foi constru?do baseado em um vocabul?rio controlado: o tesauro. O tesauro ? um tipo de vocabul?rio controlado, mais complexo, que trabalha com ambiguidade dos termos, sinon?mia, rela??es hier?rquicas e associativas e foi elaborado a partir de conceitos selecionados e seus termos relacionados presentes nos of?cios. O escopo inicial do projeto permeia o espa?o de 2011 a 2014, totalizando 239 of?cios. Para a alimenta??o do Sistema com os novos documentos que surgir?o prop?e-se a auto alimenta??o do tesauro que far? a an?lise de relev?ncia de novos termos nos novos of?cios atrav?s de um algoritmo em constru??o. O sistema estar? em ambiente virtual, para que o acesso seja democratizado e o processo de tratamento de novos of?cios seja automatizado. Sendo positiva a implementa??o do projeto, sugere-se que os demais departamentos da UFVJM utilizem o mesmo sistema para organiza??o dos seus documentos, ganhando agilidade nos processos e satisfa??o do usu?rio final na localiza??o do que procura. / Disserta??o (Mestrado Profissional) ? Programa de P?s-Gradua??o em Educa??o, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / This project arose from an actual deficiency of the UFVJM's Department of Computer Science (Universidade Federal dos Vales do Jequitinhonha e Mucuri) to store and retrieve archives. This institution has been having to put up with problems to store documents efficiently. This difficulty prevents access to documents and imposes a heavy burden to the department's staff, in terms of time to locate and retrieve information. Therefore, we developed an system to index information efficiently. To this end, we have used techniques borrowed from various areas within information science. Such techniques allowed us to automate the process of indexing new archives, optimize their recovery and, as a result, we have been able to democratize the access to information. The proposed database was built based on a controlled vocabulary: the thesaurus. The thesaurus is a controlled type of vocabulary, more complex, working with ambiguity of terms, synonymy, hierarchical relationships and associativity. It was prepared from selected concepts and terms related to these concepts in the archives. The initial scope of the project covers a time period from 2011 to 2014, totaling 239 offices. To feed the system with new documents yet to emerge we propose to self feeding mechanism. This self-feeding process will lead to the relevant analysis of new terms in the new archives through an algorithm, currently under implementation. The system will be in a virtual environment, which ensures not only the democratic access to information, but also the automatic handling of new documents. In case this project obtains positive feedback, we shall suggest that other UFVJM departments use the same system for organizing documents; hence, decreasing their response time, and improving the experience of their end-users.

The use of minocycline for the treatment of a broad range of systemic infections and for severe acne has been associated with vestibular side effects. The severity of side effects may lead to poor adherence to therapy by patients. The use of sustained release formulations of minocycline that display slow dissolution of minocycline following administration may be beneficial in reducing the incidence and severity of side effects. Therefore, sustained release capsule dosage forms containing 100 mg minocycline (base) were manufactured and assessed for use as sustained release oral dosage forms of minocycline. Minocycline sustained release capsules were manufactured based on matrix technologies using hydroxypropylmethyl cellulose (HPMC) and Compritol® as release retarding polymers. The rate and extent of minocycline release from the capsules was evaluated using USP Apparatus 1 and samples were analysed using a validated High Performance Liquid Chromatographic (HPLC) method with ultraviolet (UV) detection. Differences in the rate and extent of minocycline release from formulations manufactured using HPMC or Compritol® were influenced by the concentration of polymer used in the formulations. The rate and extent of minocycline release was faster and greater when low concentrations of polymer were used in formulations. The effect of different excipients on the release pattern(s) of minocycline and particularly their potential to optimise minocycline release from experimental formulations was investigated. The use of diluents such as lactose and microcrystalline cellulose (MCC) revealed that lactose facilitated minocycline release when HPMC was used as the polymer matrix. In contrast, the use of lactose as diluent resulted in slower release of minocycline from Compritol® based formulations. The addition of sodium starch glycolate to HPMC based formulations resulted in slower release of minocycline than when no sodium starch glycolate was used. Compritol® based formulations were observed to release minocycline faster following addition of sodium starch glycolate and Poloxamer 188 to experimental formulations. In vitro dissolution profiles were compared to a target or reference profile using the difference and similarity factors, ƒ1 and ƒ2 , and a one way analysis of variance (ANOVA). In addition, the mechanism of minocycline release was elucidated following fitting of dissolution data to the Korsmeyer-Peppas, Higuchi and Zero order models. Minocycline release kinetics were best described by the Korsmeyer-Peppas model and the values of the release exponent, n (italics), revealed that drug release was a result of the combined effects of minocycline diffusion through matrices and erosion of the matrices. These in vitro dissolution profiles were better fit to the Higuchi model than to the Zero order model. Two formulations that displayed a fit to the Zero order model were identified for further studies as potential dosage forms for sustained release minocycline.

With tighter emission regulations for road vehicles pushing the technology forward, fuel savings are indirectly affecting the designs and technical solutions of loader cranes. By decentralizing the hydraulic power through driving each actuator separately, the goal of a more efficient crane drive is strived for. This thesis analyzes if the simple concept of a pump-controlled cylinder directly driven by an induction motor is achievable for a loader crane. Further, the crucial role of the induction motor is studied both mathematically and physically. A special research is also performed on energy efficiency and the capability of electric energy regeneration. By forming the transfer function of the system and performing measurements on a physical setup, the conclusion is drawn that the proposed pump-controlled cylinder concept is fully functional for its purpose which implies that the technology is promising. The report identifies a number of complications with this configuration, such as the induction motor demonstrating reduced performance at high loads and low speeds. Suggestions of improvements are presented with regards to these issues. The thesis also demonstrates high efficiency during a lifting motion and that the possibility of efficient electric energy regeneration is achievable if an optimum lowering speed is considered.

The objective of the thesis was to analyse the reproductive traits of sows on a particular farm with regard to the method used, as observed during the period of one year. The highest rate of live-born piglets per the first litter (12.4) was reached in nucleus breeding. Regarding the mating method, the highest number of piglets born in the first litter (12.7) was reached through natural mating, followed by intrauterine insemination (12.3) and cervical insemination (11.6). During the one-year period, the rate of successful conception at first service was 83.3 per cent of sows in case of intrauterine insemination, 80.6 per cent of sows in case of natural mating and 79.2 per cent of sows in case of cervical insemination. When calculating the number of all born piglets per 100 inseminations, it was found out that 1 028 piglets were born in case of intrauterine insemination, 1 026 piglets in case of natural mating and only 921 piglets were born in case of cervical insemination, that is 107 (or 105) less. The highest number of born piglets (11.8) was reached in sows serviced when they were 256270 days old, followed by sows serviced when 241255 days old (11.1 piglets). With the gestation length under 114 days, the sows farrowed 1.2 piglets more than when the gestation length was over 115 days. With the weaning-to-conception interval under 5 days, the sows farrowed more (12.4) piglets than with the weaning-to-conception interval lasting over 6 days, which resulted in only 11.9 piglets being born.

Aside from drug users who are addicted and sometimes need expert aid, there are also individuals who can prevent the unfavourable consequences of drug use, i.e. the controlled users. These users are concealed and official records about them do not exist. This diploma thesis deals with the controlled users and their social impact. During the recent years researchers focused mainly on the controlled use of hard drugs, such as heroin or cocaine, but there is still only a very few studies dealing with the controlled use of cannabis drugs. In the theoretical part of the work cannabis is characterised from general and botanical point of view and its basic kinds (cannabis sativa, cannabis indica, cannabis ruderalis) and forms (marijuana, bhang, bhang oil) are described. Next chapter is dedicated to a brief history of cannabis drugs in the world. Other discussed topics are cannabis as a remedy as well as health consequences of cannabis drugs use. Next, the most frequent social circumstances which can cause an individual to start taking cannabis drugs are described and a typology of cannabis drugs users is introduced. The last chapter deals with the theoretical models of controlled drug use and the theory of controlled drug use in general. The aim of the work was to find out what relationship the controlled users of cannabis substances have to the respective drug. Two research questions were formulated. The first one is about whether the cannabis drug use caused any significant change in the lives of controlled users or not. The second one's purpose is to find out when it is not suitable for the controlled users of cannabis drugs to use the drug. The research sample consisted of 12 communication partners from Pilsen, seven male and five female, in the age between 21 and 35 years. The communication partners were selected for the research by snowball method. Only those individuals who were over 18 and have at least two year experience with the respective substance were selected for the research to ensure that only controlled users and no experimental users are included. Another condition was at least ten separate experiences with the use of respective drug. Individuals under research must not have suffered any damage from the cannabis drug use and must not have undergone any drug addiction treatment. The communication partners also must not have been legally prosecuted with regard to drugs. The research took place between January and April 2015. The empirical part of the work is based on a qualitative research. Data were collected via narrative interviews. In the course of this type of interview the individual under study is encouraged to narrate freely. The interviews were transcribed verbatim and are enclosed in the attachments section of the work. The data obtained from the interviews were compiled via anchored theory. The first two degrees of coding were employed in the work open coding and axial coding. The work can serve as a practical guide for cannabis drug users to become controlled users of these substances or to achieve total abstinence. It can also be used to provide complex information about the topic to general public.

A associação entre o período gestacional e o periodonto vem sendo relatada tendo diferentes plausibilidades biológicas. O periodonto é reconhecido como tecido alvo para a ação dos hormônios que têm seus níveis elevados ao longo da gestação. Uma alta prevalência de alterações periodontais tem sido relatada nesse período. Estudos recentes têm questionado a influência do período gestacional em produzir alterações significativas no periodonto. Atualmente, uma possível associação entre a presença de doenças periodontais na gestação e desfechos obstétricos tais como, o nascimento de bebês prematuros e/ou com baixo peso tem sido relatada na literatura. Para o planejamento de políticas de saúde que visem o bem estar das gestantes, bem como almejem a realização de procedimentos preventivos e terapêuticos é necessário o conhecimento de como esse período influência os diferentes órgãos, assim como diferentes condições sistêmicas e comportamentais podem interferir no curso fisiológico da gestação. Avaliar as alterações periodontais associadas a períodos com diferentes concentrações hormonais, tais como durante a gestação e no período pós-parto, assim como comparar a eficácia da terapia periodontal realizada durante a gestação com os resultados obtidos quando a mesma é executada após o parto foram os objetivos dessa tese. Gestantes com até 20 semanas de gestação realizando pré-natal no Hospital Materno Infantil Presidente Vargas, foram convidadas a participar do estudo e randomizadas em dois grupos (teste e controle). Exames clínicos avaliando a presença de placa (IPI), inflamação gengival (IG), presença de fatores retentivos de placa (FRP), profundidade de sondagem (PS), nível clínico de inserção(NIC), sangramento à sondagem (SS) e volume de fluido crevicular gengival (FCG) foram realizados no início do estudo e repetidos entre a 26-28ª semanas de gestação, 30 dias após o parto e 30 dias após a realização do tratamento periodontal para as mulheres randomizadas para o grupo controle. Após o exame inicial, as mulheres do grupo controle receberam somente 1 consulta de tratamento odontológico (padrão no hospital), tendo sido o tratamento completo realizado 30 dias após o parto. As mulheres pertencentes ao grupo teste receberam tratamento clínico e periodontal durante a gestação e foram examinadas nos mesmos momentos até 30 dias após o parto. Para as mulheres pertencentes ao grupo controle, alterações nos níveis de placa não foram observadas durante a gestação e 30 dias após o parto. Durante esse período observacional alterações estatisticamente significantes foram observadas para o IG, PS, NIC e SS. Profundidade de sondagem e SS tiveram comportamentos semelhantes, suas estimativas aumentaram durante a gestação(PS de 2.51 para 2.57mm) e (SS de 50.36 para 54.19%) e foram reduzidas após o parto (PS 2.52mm e SS 50.40%). O tratamento periodontal realizado nos dois períodos experimentais foi eficaz em restabelecer a saúde do periodonto. O percentual médio de SS após o tratamento no grupo teste foi de 11.10±7.84e no grupo controle de 8.07±5.21. Houve reduções estatisticamente significantes no IPI, IG, PS, SS e FCG nos dois grupos experimentais. Alterações no NIC não foram observadas. Entre os grupos as alterações clínicas observadas não foram estatisticamente significantes, com exceção no percentual médio de redução de SS em sítios que tinham inicialmente PS>=4mm. Pode ser concluído que durante o período gestacional alterações nos parâmetros inflamatórios relacionados ao periodonto foram observados no grupo controle. O significado clínico deve ser avaliado criticamente. A eficácia da terapia periodontal pode ser obtida de maneira similar quando o tratamento foi realizado durante a gestação ou no período pós-parto. / The association between gestational period and the periodontium has been related with different biological plausibilities. The periodontium is recognized as a target tissue for the action of the hormones whose levels increase during pregnancy. A high prevalence of periodontal alterations has been reported in that period. Recent studies recent have been questioning the influence of the gestational period in producing significant alterations in the periodontium. Currently, a possible association among the presence of periodontal diseases during pregnancy and negative obstetric outcomes such as preterm labor and/or low birth weight infants has been reported. For the planning of health policies that seek the well being of pregnant women, as well for achieving preventive and therapeutic measures it is necessary to know how this period influences different organs, as well as how different systemic and behavioral conditions may interfere in the physiologic course of pregnancy. To evaluate periodontal alterations associated periods with different hormonal concentrations such as during pregnancy and postpartum, as well comparing the efficacy of periodontal therapy performed during pregnancy with the results obtained when the same therapy is performed after delivery were the objectives this thesis. Pregnant women with up to 20 gestational weeks accomplishing prenatal care in the Hospital Materno Infantil Presidente Vargas were invited to participate in the study and randomized in two groups (test and control). Clinical examinations comprised the presence of plaque (PU), gingival inflammation(GI), presence of plaque retentive factors (FRP), probing depth(PD), clinical attchment levei (CAL), bleeding on probing (BOP) and gingival crevicular fluid(CGF) volume and was Rerformed at baseline and repeated between 26-28th gestational weeks, 30 days after delivery and 30 days after the completion of periodontal treatment for women randomized for the control group. After baseline examination, women of the control group received only 1 session of dental treatment (hospital patter), with the comprehensive periodontal care performed 30 days after delivery. Women belonging to the test group received clinical and periodontal treatment during pregnancy and were examined in the same moments up 30 days after delivery. For the women belonging to the control group, alterations in the plaque levels were not observed during pregnancy and 30 days after delivery. During the observational period, statistically significant alterations were observed for GI, PO, CAL and BOP. Probing depth and SS behaved similary, with their estimates increasing during pregnancy (PD from 2.51 to 2.57mm) and (BOP from 50.36 to 54.19%) and reducing after delivery after delivery (PD 2.52mm and BOP 50.40%). Periodontal performed in both groups was efficacious in reestablishing periodontal health. The mean percentage of BOP after the treatment in the test group was of 11.10±7.84and in the control group was of 8.07±5.21. Statistically significant differences in PU,GI, PD, BOP and GCF were observed in both groups. Alterations in CAL were not observed. Among groups, the clinical alterations observed were not statistically significant, with the exception in the mean percent reduction of BOP in with PD>=4mm at baseline. It may be concluded that alterations in the inflammatory parameters related to periodontium were observed during pregnancy in the control group. The clinical significance of this finding should be critically appraised. The efficacy of periodontal therapy can be obtained similarly if the treatment is performed during pregnancy or after the delivery.

A fabricação de peças mecânicas por usinagem tornou-se mais versátil com o uso de máquinas-ferramentas com Comando Numérico Computadorizado. Este recurso permitiu a obtenção de superfícies de geometria mais complexa, extremamente difíceis de se fabricar com máquinas convencionais. A tarefa de escrever os programas CNC para usinar tal geometria também não é fácil, sendo necessário recursos auxiliares para alcançar este objetivo. O embasamento para utilização desta tecnologia passa inicialmente pelos conceitos e fundamentos de máquinas-ferramentas com CNC, programação CNC e modelagem geométrica de superfícies. Na elaboração deste estudo foram analisados vários relatos sobre sistemas de geração de programas CNC, tipos de trajetórias de ferramentas, otimização de programas CNC, reconhecimento de forma e sistemas de simulação e verificação. Desta análise foi estruturada uma estratégia para realização deste trabalho, que trata da implementação de um sistema de geração de programas CNC para máquinas de 3 eixos, destinado a superfícies de forma livre. O software admite modelos de superfícies criadas em um modelador na forma paramétrica Bézier e gera segmentos de programa CNC para usiná-las em duas etapas: desbaste e acabamento. Do modelo paramétrico são geradas duas poligonalizações para estas duas etapas. A primeira, de menor resolução, é usada para a operação de desbaste, para seleção de ferramentas e para determinação das inclinações da superfície, dados necessários para a operação posterior. A segunda, de maior resolução, oferece melhores condições de aproximação da superfície paramétrica e permite a geração da trajetória usada no acabamento. A etapa de desbaste, destinada à remoção do excesso de material da peça, é realizada com uma ferramenta de extremidade cilíndrica trabalhando em vários planos de corte. Cada plano é usinado através de movimentos em ziguezague, e posteriormente faz-se uma trajetória equidistante ao contorno das cavidades ou protrusões existentes. Já a etapa de acabamento, que visa conferir a forma e dimens5o desejadas à peça, é realizada com uma ferramenta de extremidade esférica trabalhando em ziguezague por toda a superfície. Nesta etapa, são determinados espaçamentos diferenciados entre os movimentos da ferramenta, segundo as inclinações da superfície. Desta forma, consegue-se uma redução no número de comandos, sem perder em qualidade. Três casos são apresentados, sendo o primeiro, uma superfície formada por toda cavidade e uma protrusão, o segundo, uma cavidade e o terceiro uma protrusão. O primeiro caso apresenta todos os passos executados nestas etapas consideradas. Os demais apresentam os resultados obtidos. Para verificar o programa CNC gerado foi implementado um simulador que confere o resultado obtido com a superfície modelada na forma paramétrica. Este simulador também tem um funcionamento diferenciado para cada etapa de usinagem e confere uma boa precisão a peça acabada. Os resultados demonstram a eficiência do sistema quanto à sua rapidez e também quanto à forma da peça. Em função das resoluções consideradas nos sistemas de geração e de simulação, encontrou-se um erro entre a superfície paramétrica e a superfície simulada. Conclui-se que a utilização de maior resolução para a geração da trajetória da ferramenta na etapa de acabamento é decisiva para a redução do erro encontrado comparando o modelo paramétrico com a superfície simulada. / Manufacturing of mechanical pieces by machining became more versatile with the use of tool machines equipped with Computerized Numerical Control. This resource allows more complex geometry surfaces, which are very difficult of manufacture with conventional machines. Writing of CNC programs for machining such geometry is also not easy, demanding further resources to fulfill this goal. Basics of using this tecnology includes concepts and fundamentals of CNC tool machines, CNC programming and geometrical modeling of surfaces. In this dissertation, it were analysed several reports of CNC tool path generation systems, tool path types, CNC program optimization, form recognition and simulation and verification systems. From this analysis, it was designed a strategy to prepare this dissertation, whose main purpose was to implement a CNC program generation system for 3 axis machines for free-form surfaces. The software admits surface models designed in a modeler using Bezier parametric form and generates segments of CNC programs for machining in two stages: rough and finishing. From the parametric model, two poligonalizations are generated for these stages. The first, of lower resolution, is used for a rough operation, for tools selection and for determination of surface inclinations, which ares necessary data for later operations. The second poligonalization, of greater resolution, offers better conditions of aproximation to the parametric surface and allows the generation of the tool path used in finishing. The rough stage, used to remove excess of material in this piece, is realized with a cylindrical end cutter working in several cutting planes. Every plane is machined in zigzag movements and later is done a tool path with constant offset with the existent cavity or protrusions. The finishing stage, whose goal is to give the desirable form and dimension to the piece, is done with a ball-end cutter, working in zigzag upon the whole surface. In this stage, no equal distances are determined betwen the tool movements according to surface inclinations. Thus, a reduction in the number of commands is obtained without loss of quality. Three cases are presented, where the first one is a surface formed by a cavity and a protrusion, the second one is a cavity, and the third one is a protrusion The first case is completely presented with all the steps. In the others cases, results are given. In order to evaluate the generated CNC program, it was implemented a simulator that checks the results with the modeled surface. This simulator uses different approaches in each stage of machining and gives a good precision to piece finishing. The results demonstrate the system eficiency as to speed, performance and also to form. On account of resolutions considered in the generation system and in simulation, errors were found between the parametric and the simulated surfaces. Comparing the parametric model with the simulated surface, it is clear that the use of greater resolution during the generation of the tool path in the finishing stage is decisive to reduce the errors.