"Many assembly machines for consumer products suffer from the fact that the mechanisms used to impart the necessary assembly motions to the product are orders of magnitude more massive than the product payloads that they carry. This characteristic subsequently limits the operating speed of the machine. If the follower train could be made less massive without sacrificing accuracy and control, it would therefore allow higher speeds. It is well-known that structures that carry only tensile loads can be much less massive than those that must also carry compressive loads. This concept is demonstrated in many structures, such as the suspension bridge. This master’s project set out to investigate the feasibility of a tension-member follower train for a generic cam-driven pick and place mechanism. This system was first dynamically simulated using a computer model, and then tested by constructing a proof of concept prototype. A cam-driven, low-mass tension member (in this case a spring steel strip over pulleys) under spring preload was used to replace the bellcranks and connecting rods typical of a conventional follower train. The system was determined to be feasible and will allow for increased operating speeds at potentially lower costs as an additional benefit."

Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2018-07-24T13:33:46Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Bruna Hilgemberg.pdf: 2456286 bytes, checksum: 1f094c1efd8bce8788da73b56ecf38e8 (MD5) / Made available in DSpace on 2018-07-24T13:33:46Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Bruna Hilgemberg.pdf: 2456286 bytes, checksum: 1f094c1efd8bce8788da73b56ecf38e8 (MD5) Previous issue date: 2018-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo do presente estudo foi avaliar o efeito de diferentes protocolos adesivos na resistência de união de diferentes compósitos CAD/CAM por meio do teste de microcisalhamento (μSBS). Para esse experimento, três tipos de compósitos CAD/CAM foram utilizados: 1) [Lava™ Ultimate CAD/CAM Restorative (3M ESPE) - LU], 2) [Brava block CAD/CAM (FGM)- BR] e 3) [Vita Enamic (Vita Zanhfabrik) - VE]. Quarenta e cinco secções retangulares (10 × 10 × 6 mm) de compósitos CAD/CAM foram utilizados para a avaliação de microcisalhamento, esses blocos foram distribuídos de acordo com as variáveis: Compósitos CAD/CAM (1- LU, 2-BR, 3- VE) vs. sistema de cimentação [1- Prime & Bond Elect (PBE) + Enforce, 2- Scotch Bond Universal (SBU) + Rely X Ultimate, 3- Ambar Universal (AU) + All cem, 4- Silano sem MDP + Enforce, 5- Silano sem MDP + Rely X Ultimate, 6- Silano sem MDP + All Cem, 7- Silano com MDP + Enforce, 8- Silano com MDP + Rely X Ultimate, 9- Silano com MDP + All cem], resultando em 27 grupos experimentais. O sistema adesivo foi aplicado e matrizes de Tygon foram preenchidas com cimento resinoso e fotoativadas. Os espécimes foram armazenados em água (37 °C por 24h) e submetidos ao teste de μSBS, seus resultados foram submetidos ao teste de ANOVA 2-fatores seguido pelo teste de Bonferroni, α = 5%). Quinze secções retangulares adicionais foram avaliados em Microscopia eletrônica de varredura (MEV/EDS) para a análise da morfologia e composição após tratamento de superfície conforme recomendação de cada fabricante. Para os três cimentos utilizados, maiores valores de μSBS foram observados na superfície VE, seguido do LU e do BR respectivamente. A diferença significativa entre os sistemas de cimentação foi observada apenas no compósito VE, que apresentou maiores valores de μSBS, com exceção dos grupos silano com MDP + All Cem, silano sem MDP + Rely X Ultimate e SBU + Rely X Ultimate. Foi encontrado para todos os grupos, pouca ou nenhuma porcentagem de falha coesiva em cimento, maior porcentagem de falha adesiva/mista, com exceção dos grupos VE/AU e VE/silano com MDP/All Cem, VE/silano sem MDP e VE/SBU/Rely X Ultimate e VE/AU e VE/silano com MDP/ Enforce, em que foi encontrado maior porcentagem de falha coesiva em compósitos CAD/CAM. Todos os compósitos apresentaram irregularidades após o tratamento de superfície na análise de MEV, porém maior irregularidade foi observada na superfície do VE, seguido do LU e do BR respectivamente. A análise por EDS, confirmou a composição de cada compósito CAD/CAM e após o tratamento de superfície, houve diminuição da porcentagem de sílica e zircônia apenas para LU. Pode-se concluir que a efetividade do protocolo de cimentação está relacionada ao tipo de compósito CAD/CAM e suas diferentes composições e que independente do protocolo de cimentação, o VE apresentou os melhores valores de resistência ao microcisalhamento em comparação aos outros compósitos CAD/CAM avaliados. / The objective of the present study was to evaluate the effect of different adhesive protocols on the bond strength of different CAD / CAM composites by means of the micro-shear test (μSBS). For this experiment, three types of CAD / CAM composites were used: 1) [Lava ™ Ultimate CAD / CAM Restorative (3M ESPE) - LU], 2) [Brava block CAD / CAM (FGM) Vita Enamic (Vita Zanhfabrik) - VE]. Forty-five rectangular sections (10 × 10 × 6 mm) of CAD / CAM composites were used for the evaluation of micro-shear, these blocks were distributed according to the following variables: CAD / CAM composites (1 LU, 2-BR, 3 - VE) vs. (1) Prime & Bond Elect (PBE) + Enforce, 2- Scotch Bond Universal (SBU) + Rely X Ultimate, 3- Ambar Universal + All Cem, 4- Silane without MDP + Enforce, 5- Silane without MDP + Rely X Ultimate, 6- Silane without MDP + All Cem, 7- Silane with MDP + Enforce, 8- Silane with MDP + Rely X Ultimate, 9- Silane with MDP + All Cem], resulting in 27 experimental groups . The adhesive system was applied and Tygon matrices were filled with resin cement and photoactivated. The specimens were stored in water (37 ° C for 24h) and submitted to the μSBS test, their results were submitted to the 2-factor ANOVA test followed by the Bonferroni test, α = 5%). Fifteen additional rectangular sections were evaluated in Scanning Electron Microscopy (SEM / EDS) for analysis of morphology and composition after surface treatment as recommended by each manufacturer. For the three cements used, higher values of μSBS were observed on the VE surface, followed by LU and BR respectively. The significant difference between the cementation systems was observed only in the composite VE, which presented higher values of μSBS, except for the silane groups with MDP + All Cem, silane without MDP + Rely X Ultimate and SBU + Rely X Ultimate. A higher percentage of adhesive / mixed failure was found for all groups, except for the VE / AU and VE / silane groups with MDP / All Cem, VE / silane without MDP and VE / SBU / Rely X Ultimate and VE / AU and VE / silane with MDP / Enforce, in which a higher percentage of cohesive failure was found in CAD / CAM composites. All the composites presented irregularities after the surface treatment in the SEM analysis, but greater irregularity was observed on the surface of the VE, followed by the LU and the BR respectively. The EDS analysis confirmed the composition of each CAD / CAM composite and after the surface treatment, the percentage of silica and zirconia was reduced only for LU. It can be concluded that the effectiveness of the cementation protocol is related to the type of CAD / CAM composite and its different compositions and that regardless of the cementation protocol, the VE presented the best values of micro-shear strength compared to other CAD / CAM composites evaluated.

Engenharia reversa é o conceito de se produzir uma peça tomando como base um original ou modelo físico existentes, sem o uso de desenhos de engenharia. Empresas se voltam para a tecnologia da Engenharia Reversa como um complemento valioso para toda a gama de ferramentas CAD/CAM que elas possuem, devido às dificuldades encontradas quando se necessita trabalhar com superfícies de forma livre. Desta forma, faz-se necessária uma ferramenta que proporcione a inserção das formas deste modelo em um sistema CAD, de forma que se possa usufruir de todas as possibilidades, oferecidas por ele. Neste trabalho, é apresentada uma revisão bibliográfica que aborda a engenharia reversa desde sua origem até as técnicas avançadas existentes atualmente, ou seja, apresentando equipamentos e sistemas específicos usados atualmente para a prática de engenharia reversa. Mostra-se um sistema de engenharia reversa, que foi projetado e implementado realizando a integração desde uma máquina de medir 3 coordenadas até um centro de usinagem CNC com o auxílio de um software CAD comercial, o qual possui módulo de CAM integrado. São apresentados também 3 estudos de casos. / Reverse engineering is the concept of making a part based on an original or existing physical model, without engineering drawings. Companies are using reverse engineering technology as a valuable complement to many of their CAD/CAM tools, due to their difficulties of working with free-form surfaces. It is necessary a tool which provides the insertion of the model forms in the CAD system, therefore enabling to take advantages of all possibilities offered by the system. The Reverse Engineering has developed beyond the traditional copy milling. It is presented a review of the reverse engineering since its origin until recent advanced techniques, where the equipments and specific systems used for reverse engineering practice nowadays are showed. In this work a reverse engineering system has been designed and implemented, which is accomplished by the integration from the coordinate measuring machine until a CNC machining center, by using a commercial CAD software with integrated CAM module. In order to validate the system developed, three case studies are also presented.

This master’s thesis is based on the idea to extend a point-to-point 10 Gbps Ethernet cryptoto a multi-point 10 Gbps Ethernet crypto. The multi-point extension is targeted for a fictiveproduct called Krypet. Extending Krypet to multi-point can be seen as creating a distributed Ethernet switch wherethe ports are Krypet units and the information passed between the ports is encrypted. Problems that occur when this extension is designed are identified and analysed. Some problemexamples are address lookup, session changes and packet switching. Different solutions to the identified problems are presented and these are compared anddiscussed. Requirements on the whole multi-point extension are determined and an architecturebased on the solutions is designed. The architecture is implemented and the resultof the implementation is discussed. The implementation successfully extends the system tomulti-point support and satisfies most of the determined requirements.

Composed of a left mold and a right one, an open and close molding mechanism is widely used in various plastic industries. The aim of this study is to design cam-link mechanisms whose right mold motions can rapidly synchronize with their left mold motions so that the mechanisms have higher stiffness for reducing residual vibration. In structural design of a molding mechanism, the device is actuated by a planar cam mechanism. And a set of cam actuated links is synthesized to drive the left mold. Then, another set of links connected to one of the left mold links is used to synchronously actuate the right mold together with the left mold. This study first is to synthesize the B-Spline curves for the left mold motion. Subsequently, the linkage sizes are modified base on the mechanical advantages. Then, the motion curves of the right mold and the cam follower device can be analytically determined. And the rigid body dynamic behavior of the mechanism is analyzed. Finally, the geometry of the cam is analyzed and the size of the cam follower rollers are selected to achieve the longer life time at the working speeds. This research presents eight different design cases to investigate the kinematic and dynamic characteristics of the molding mechanism. As a result, a case with improved kinematic and dynamic performance is selected.

Globoidal cam indexing mechanism (GCIM) plays an important role in automation and machining tools. With the compact structure, a GCIM is able to reach the required precision on account of high stiffness and minimized backlash. The requirement to improve the indexing accuracy for GCIMs from industry applications drives the research going on. In this dissertation, two strategies to improve the indexing accuracy of GCIMs are proposed. The first strategy is by considering the manufacturing parameters involved in the processes of machining and assembly. Analytical expressions for the turret motion and indexing accuracy of grooved GCIMs have been identified. Based on the kinematic and geometric relationships between the cam and its roller-follower turret, the effects on the output of the cam mechanism due to clearances (between the cam and roller; in the roller bearing), preload (change of the distance between input and output shafts), and the cam taper angle have been investigated. As a result, the roller alternation in the cam-turret system can be analyzed. Favorable parameters for the design, machining, and assembly can be selected to manufacture such devices with improved turret motion and indexing accuracy. Worked examples are given to demonstrate the applications of the approach. The second strategy is a technique for designing torque balancing cam (TBC) systems that are composed of spring-loaded planar cams with translating followers for GCIMs. Such a device can be attached to the input shaft of a GCIM to reduce the variation of its cam rotational speed. As a result, for high-speed applications, the intensity of residual vibrations of a GCIM can be decreased and its indexing accuracy can be improved. To approximate the required counterbalancing torque curves, nonparametric rational B-splines have been applied to synthesize the planar cam motion programs. Experimental results have also been shown in a practical and high-speed application to prove such a TBC mechanism is useful and effective.

Abstract The gear-cam intermittent mechanism, mainly made up by cam, the sun gear, planet gear and planetary shelf , it has been used in automatically high speed die cutting and creasing machine. The main function of die cutting and creasing machine is cutting and creasing the cardboard, and through compounding the cam motion curves, it will can control the intermittent motion of a gear-cam intermittent mechanism and improve its dynamic characteristic. The effects of gear cam profile and driving speed on the dynamic responses of a box folding and die cutting machine are studied in this work. The input driving motor¡Bgear¡Bgear-cam and output chain mechanics are included in the dynamic system. The equation of motion of the whole system in derived by employing Lagrange¡¦s equation the 4th order Runge-Kutta method is used to simulation the fine domain response of the nonlinear equation of motion. The effect of cam profile, and driving speed on the system dynamic response have been simulated and analysed in the work.

The purpose of this study was to describe the extent and nature of CAM services that are provided and used in Texas hospices. The study investigated the significance of hospice setting characteristics such as age, geographic location, agency type, profit orientation, Medicare certification, and number of patients served as they relate to the likelihood of offering CAM, using a robust methodological and analytical strategy. Data was collected via self-administered mail surveys to 369 hospice directors in the state of Texas. A total usable response rate of 35.7% was obtained after an initial and one follow-up mail-out. A majority (N = 62, 56.4%) of hospices provided at least one type of CAM to their clients; however, a sizeable proportion of patients did not utilize the provided CAMs. The most frequently offered CAMs included massage, music, relaxation, spiritual healing and pet therapies with females and non-Hispanic whites being the most frequent users of these CAM services. Among CAM providers, short length of stay and funding were the primary obstacles to CAM provision, with most hospices relying on a combination of general hospice funds and volunteers to sustain the delivery of CAM services. The odds of offering CAM in ‘not-for-profit’ hospices were approximately four times higher than in ‘for-profit’ hospices (OR = 3.77, p = 0.022), while the odds of offering CAM increased by 13% for every 100 patients served by hospices (OR = 1.131, p = 0.015). Other hospice setting characteristics were not significantly related to CAM provision. In conclusion, a majority of hospices offered CAM services to their clients, although many patients are not utilizing these services. This observation might be connected with the fact that most CAM services are currently not being reimbursed through the Medicare Hospice Benefit, a government program that a majority of hospices depend upon for the coverage of substantial portions of their end-of-life services. Nevertheless, our study showed that CAM provision is related to the number of patients served and profit orientation status, but is not related to other measured characteristics of hospices. / text

Ankstesni tyrimai, susiję su laikinėmis sinapsinio efektyvumo pasikeitimo taisyklėmis per nuo veikimo potencialų poravimo priklausantį plastiškumą, praktiškai nekreipė jokio dėmesio į neuronų erdvines savybes. Mes nagrinėjame nuo kalcio/kalmodulino priklausančią kinazę II (CaMKII) ir kalcineuriną (CaN) artimuosiuose ir tolimuosiuose spygliuose bei jų įtaką ilgalaikei potenciacijai ir ilgalaikei depresijai. Tyrimų metu buvo atskleista, kad esant neigiamam veikimo potencialų laiko poravimui tolimoje sinapsėje gali vykti ilgalaikė potenciacija, tuo tarpu artimajame spyglyje visi procesai vyksta remiantis klasikinėmis sinapsinio plastiškumo taisyklėmis. Gauti rezultatai teigia, kad sinapsės vieta dendritiniame medyje yra lemiamas veiksnys nuo veikimo potencialų laikų poravimo priklausančiame sinapsiniame plastiškume. / Previous studies focusing on the temporal rules governing changes in synaptic efficacy during spike timing-dependent plasticity (STDP) have paid little attention to spatial characteristics of neurons. We analyze the activity of calcium-calmodulin dependent protein kinase II (CaMKII) and phosphatase calcineurin (CaN) in proximal and distal spines and their impact on long-term potentiation (LTP) and long-term depression (LTD). During tests we found that at negative timing of action potentials in distal spine synapse can undergo LTP while in proximal spine the processes follow the classic STDP rules. Our results suggest that synapse location within the dendritic tree is a crucial determinant of STDP.

- / -