Objetivo: Avaliar a interface pilar protético/implante e o destorque, quando utilizados parafusos recobertos com Diamond-like carbon (DLC) e parafusos convencionais de titânio para fixação dos componentes protéticos, antes e após ação de carga cíclica. Posteriormente, avaliar a correlação entre o desajuste vertical da interface pilar UCLAimplante e o destorque dos parafusos dos pilares. Método: Trinta e seis implantes foram divididos em quatro grupos de acordo com o tipo de conexão (hexágono externo e interno) e do parafuso utilizado para fixar o pilar ao implante (titânio ou recoberto com DLC), ou seja: Grupo A: hexágono externo/parafuso titânio; Grupo B: hexágono externo/parafuso recoberto com DLC; Grupo C: hexágono interno/parafuso titânio;Grupo D: hexágono interno/parafuso recoberto com DLC. Após os implantes terem sido incluídos em resina acrílica incolor, coroas foram enceradas sobre pilares UCLA, fundidas com liga metálica de Ni-Cr-Ti e parafusadas aos implantes com aplicação do torque recomendado pelo fabricante. Em seguida, as interfaces pilar/implante foram mensuradas, em microscópio de luz, em quatro pontos de cada amostra (DV1). Após as amostras terem sido submetidas a um milhão de ciclos mecânicos, as interfaces foram novamente mensuradas (DV2). Para comparar os valores médios, intra e intergrupos, das interfaces pilar/implante, da diferença entre os mesmos e os valores de destorque, os dados foram submetidos à Análise de Variância, ao teste t de Student e ao teste de Mann Whitney (p≤0,05). E para a correlação entre os fatores estudados, os resultados foram submetidos ao teste de correlação de Pearson (p≤0,05). Resultados: Os implantes com hexágono externo apresentaram os maiores valores de desajuste vertical pilar UCLA/implante antes (DV1) e após (DV2) ciclagem mecânica (GA/DV1 = 59,81μm e GA/DV2 = 62,59μm, GB/DV1 = 73,73μm e GB/DV2 = 72,95μm). Nos grupos onde foram utilizados parafusos de titânio foi observado aumento dos valores da interface pilar/implante de DV1 para DV2 (GA = de 59.81μm para 62.50μm e GC = de 18.13μm para 22.54μm). Nos grupos onde foram utilizados parafusos de DLC foi evidenciada redução dos valores da interface pilar/implante de DV1 para DV2 (GB = de 73.73μm para 72.95μm e GD = de 16.07μm para 14.47μm. Somente o GC apresentou diferença significativa entre os valores mensurados na interface pilar/implante antes e após o carregamento cíclico (p=0,05). Para correlacionar os valores de destorque aos valores das interfaces pilar/implante, foi aplicado o teste de correlação de Pearson, porém não foi verificada diferença significativa entre os fatores estudados (p˃0,05). Conclusões: As interfaces pilar UCLA/implante foram maiores nos grupos com hexágono externo que nos grupos com hexágono interno, porém sem diferença significativa quando utilizados parafusos de titânio ou revestidos com DLC. Houve perda de torque após carga cíclica em todos os grupos. Não é possível afirmar que um maior valor de interface pilar/implante esteja correlacionado com o desaperto do parafuso. / Purpose: To evaluate the interface abutment/implant, and the loosening screws values when used screws with Diamond-like carbon (DLC) coated and conventional titanium screws for fixation of prosthetic components, before and after action of cyclic loading. After, to evaluate the connections between the values of interface abutment UCLA/implant and loosening screw. Method: Thirty six implants were divided into four groups according to the type connection (external hexagon and internal hexagon) and screw used to fix the abutment to the implant (titanium or coated with DLC): Group A: external hexagon / titanium screw; Group B: external hexagon / DLC screw; Group C: internal hexagon / titanium screw; Group D: internal hexagon / DLC screw. After the implants were included in colorless acrylic resin, crowns were waxed using UCLA type abutment, casting with metal alloy of Ni-Cr-Ti and screwed to the implants using the torque recommended by the manufacturer. Then the interfaces pillar/implant were measured with light microscope in four pre-marked points (DV1). After the sets (implant, crown and screw) were subjected to one million mechanical cycles and the interfaces measured again (DV2). Analysis of Variance, Test t Student and test Mann Whitney (p≤0,05) were applied to compare the average to the interfaces abutment/implant intra and intergroup, the difference between the same and the loosening screws values. And to evaluate the correlated between the factors studying, the Pearsons correlation test (p≤0,05). Results: The implants with external hexagon exhibited the higher values of the vertical misfit pillar UCLA/implant before (DV1) and after (DV2) cyclic loading (GA/DV1 = 59,81μm e GA/DV2 = 62,59μm, GB/DV1 = 73,73μm e GB/DV2 = 72,95μm). In groups of titanium shows screws there was an increase in interface abutment/implant after cyclic loading (GA = 59,81μm to 62,50μm and GC = 18,13μm to 22,54μm) and in groups with DLC coated screws there was a reduction the values of interface abutment/implant (GB = 73,73μm to 72,95μm and GD = 16,07μm to 14,47μm). Only group C showed a statistically significant difference to the interface abutment/implant before and after cyclic loading (p = 0.05) exhibited mean values and differences between the interfaces pillar/implant. To correlate the values of loosening to the values of pillar interfaces/implant was applied the Pearsons correlation test, but there was no significance among the studied factors (p ˃ 0.05). Conclusions: The interfaces pillar UCLA/implant were higher in groups with external hexagon connection those in groups with internal hexagon, but without significant differences when use titanium screws or coated with DLC. Always screws loosed torque after cycling load. Is not possible to affirm that a higher value of interface abutment/implant be correlated with the loosening screw.

Diploma thesis deals with a topic of lubrication and cooling of the ball screw rotary nuts. The first part is focused on a research behind the theory of ball screws and ball screw rotary-nuts. The three types of construction were developed in the second half of the thesis. Each construction is designed as an external attachable cooling and lubrication unit, which can be installed on an existing, slightly modified ball screw rotary-nut. For cooling and lubrication, only one type of medium is used and that is a cooled oil. External unit provides medium flow to ball screws working space. On top of diploma thesis tasks a design concept of ball screw rotary-nut with an integrated cooling and lubrication is introduced itself. Both described designs could become interesting for an industrial market.

This final project solves a proposal of mechanism for splitting of unfilled cans before a can filling process in the food industry. From all possible options such as the one with a simple conception, easy applicated in practice and at a low price, should be chosen. The selected option is constructed and drawn in a 3D programme called AUTODESK Inventor 10. Please, see the attached technical drawings for the chosen parts.

Master´s thesis is directed for long ball screws of nut. It is here wrote their principle, essential type, parameters and current status of single used components. For this thesis is created at program Microsoft Excel methodical calculating of required parameters ball screws of nut. Another they are investigated status of affect length shaft ball screws, as mode storage, type actuator and possible damping. In last part is solved the design of supports long shaft ball screws and is here proposed conceptual process used supports.

No description available.

BACKGROUND: The temporary anchorage devices (TAD) rely on mechanical retention to achieve their function. Following dental implants, the design has not been thoroughly studied. Most of the TADs available in the market are either conical or cylindrical homogenous designs. This study aims to evaluate whether a non-homogeneous design would be able to achieve better biomechanical properties than the current mini- screw designs available on the market. MATERIAL AND METHODS: This is a preliminary study comparing two different 1.5mm TAD designs, the Spider Screw® (Ortho Technology®), and one experimental TAD, the Novel TAD Design (NTD). The two TAD designs were generally described and evaluated following the ANSI/ADA Standard No. 178, then the core diameter / TAD diameter ratio was calculated at 0, 2, 4, and 6mm using the Mitutoyo PH-3500 projection machine in combination with QM-data 200. 10 TADs from each design were inserted in a 30 PCF laminated block from SAW Bone under a 12N axial load, using the Instron 5566A to measure the insertion torques and removal torques. Torque ratios were then calculated. Using the same Instron machine with TADs fully inserted in the artificial bone (2 per design per angle), pull-out tests were performed at angles of 0° / 30° / 60° / 90°. The TADs were loaded up to failure. One-way ANOVA and student's t-test were used for statistical analysis. RESULTS: The Spider Screw® is a conical, self-drilling, self-tapping design with the following general dimensions (d1: 1.5mm ; d2: 0.5mm; d3: 3.4mm; k1: 1mm; k2: 2mm; L1: 9.5mm; L2: 6.5mm; L3: 6.2mm), a 0.6mm pitch, 0.3mm thread depth, asymmetrical triangular threads. NTD, it is a cylindrical-conical, self-tapping design with the following general dimensions (d1: 1.5mm; d2: 0.85mm; d3: 2.5mm; k1: 1mm; k2: 2mm; L1: 9mm; L2: 6mm; L3: 6mm), a 0.5mm pitch, double threads in the first 2mm, a variable thread depth (0-2mm: 0.2mm ; 3-5mm: 0.35mm) and symmetrical rectangular threads. The core to width ratios for the Spider Screw® and NTD were respectively 1 ; 0.64 ; 0.61; 0.54 and 0.7; 0.53; 0.56 and 0.58. Mean insertion torque, removal torque and torque ratio for the Spider Screw and the NTD were respectively (12.78 N.cm / 11.32 N.cm, 0.90 ; 12.73 N.cm / 12.65 N.cm, 0.99 ) Mean pull-out forces at 0°/30°/60° and 90° for the Spider Screw® and the NTD were respectively 124.18 N / 108.59 N / 69.67 N / 84.75 N and 137.72 N / 109.7 N / 64.96 N / 66.78 N. There were no statistically significant differences found. CONCLUSIONS: After evaluating both of the TADs, it is clear that the designs are relatively different. The NTD showed to have a higher torque ratio, and therefore it could mean that the design would be clinically more effective. The NTD showed to perform as good or even slightly better than the Spider Screw® design, but a larger variety of TAD designs is needed to be able to confirm the conclusions of this study. / 2023-03-02T00:00:00Z

Melt granulation is a versatile process that is underutilized in the pharmaceutical industry. Most pharmaceutical wet granulation and twin-screw extruders can be adapted for melt granulation. Twin-screw melt granulation (TSMG) is of interest since is a continuous process and allows for flexible process design and a high degree of control. TSMG can be used to produce formulations for oral immediate or sustained release. This research focuses on the use of TSMG to taste-mask APIs. Many APIs are bitter or unpleasant tasting. Taste-masking may be required, particularly for products intended for pediatric patients. Taste-masking has been achieved with many different techniques, but a simple, cost-effective method that can be applied to many different APIs is not currently available. A matrix encapsulation approach using continuous twin-screw melt granulation was attempted with three different APIs. The resulting granule properties, particularly particle size, are related to the granulation process parameters. Prediction of taste-masking based on in vitro assessments is challenging and generally clinical evaluation is required. A small-volume dissolution method was developed as a screening test the melt granules. It is not clear if this technique is predictive of clinical taste-masking performance, but it is expected to be an improvement over discrete sampling or typical quality control dissolution methods. The dissolution rate was estimated using the Noyes-Whitney equation and correlated to the mean granule particle size. From this, a simple model for time to a taste threshold could be used to define a design space around the granulation process. / Pharmaceutical Sciences

Granulation is an important process for industries ranging from plastics to food and pharmaceutics. In the last decades, the twin-screw extruder has been more and more studied as a continuous method for granulation. But there are many questions remaining to be answered such as the functions of kneading block and the granulation behavior in this zone, the influence of the wetting method, and also the influence of the active pharmaceutical ingredient (API) properties on the granulation process. Therefore, in this project, a series of experiments were performed based on a new technique to the granulation field named ‘screw pullout’ for understanding the granulation process within the twin-screw extruder. In order to understand the specific function of an important screw element known as a kneading block, the physical particle motion reflecting progress of granulation was monitored along the screw. Different feed rate and formulations were studied; the residence time and pressure in kneading block were measured; and the granules along the screw were characterized for their porosity and size distribution. It was found that granule consolidation and breakup within the kneading block allowed the production of granules with consistent properties and excellent mechanical strength. However, the changes produced by a kneading block are dependent upon the formulation. For example, the kneading block demonstrates no observable function with formulations containing a significant content of microcrystalline cellulose. The most notable benefit of the kneading block to all tested materials appeared to be distribution of the interstitial binding liquid rather than to compact the powders. A new wetting method using a foam binder has been studied intensively in this work to assess its influence on the granulation process. A series of studies have been performed to compare the granule development along the screws as powder formulation and screw design were varied to test for the differences induced by the two wetting methods (foam delivery or liquid injection). The evolution of the granules along the screw was characterized by analyzing the particles size distribution, porosity, and fracture strength. It was found that the wetting method had minor impact on the particle size distribution due to the strong mechanical dispersion inherent to the extruder. The major finding for the pharmaceutical industry was that the foam method reduces the required amount of liquid to granulate, thereby dropping drying time after the process. The foamed binder was also found to be preferred when the formulation contains powder components with poor spreading properties. Finally, the influence of an API’s physical properties on granulation was studied by comparing formulations with varying API hydrophobicity. It was found that the API and binder distribution was not affected by the hydrophilicity of API, while the particle size distribution, porosity and fracture strength were strongly dependent on the properties of the API. / Thesis / Master of Applied Science (MASc)

No description available.

Yes / It has been shown that seeded granules of calcium carbonate can be produced in commercial batch high shear granulators such as the Cyclomix high-shear impact mixer. Seeded granules are attractive to the pharmaceutical industry due to their high uniformity and good mechanical properties which can assist efficient tablet manufacture. In the current study, attempts to produce seeded granules of Durcal 65 and PEG 4000 binder using hot melt granulation are reported, in response to the recent shift towards continuous pharmaceutical manufacturing. Various screw configurations and rotation speeds were investigated in a series of experiments to determine the relationship between process conditions and granule properties. Particle size analysis, strength measurement and structural characterisation were used to quantify granule properties. It was found that using a series of kneading elements arranged at a 60° staggering angle located near to the feed section of the extruder screw generated strong, spherical granules. From structural characterisation approximately 5–15% of extruded granules were found to be seeded. Twin screw melt granulation is therefore considered to be a promising technique for continuous production of seeded granules, although a more detailed investigation is required to optimise yield and quality.