Responses of partially edentulous subjects to variations in denture forms as determined by intra-oral force measurements

The purpose of this investigation was to study patients' responses to changes in denture forms as determined by intra oral force measurements. A group of subjects was selected requiring treatment with complete upper and partial lower Kennedy class 1 dentures. In addition to recording medical and dental histories, tests of oral stereognostic and motor ability were employed, together with a Clinical Interview Schedule, so as to exclude those with characteristics reported as reducing oral adaptability. An impression procedure was evolved, assessed and used to record the neutral zone in the test subjects. A complete upper and two lower dentures were made, the second being the test prosthesis. Its flanges were initially contoured to fill the neutral zone, and it was capable of being altered both buccally and lingually to fill more of the available space in the mouth. A miniature force transducer was developed, such that eight devices could be inserted into the test prosthesis to record simultaneously forces on the anterior and posterior aspects of the buccal and lingual flanges with a computer-based system. A regimen of tests was developed to examine the forces exerted on the varied shapes of the denture. The magnitude and the nature of the forces were analysed in relation to activity, location, head-angulation, time-interval and thickness. Marked differences in force patterns were observed. Swallowing forces were predominantly higher than those when speaking, chewing, sucking and resting. Forces related to location were significantly different. No correlation was found between force value and head-angulation. Forces recorded when contours were changed were found to be reduced significantly a fortnight later. Forces recorded on the original contours, at the beginning and end of the experiment, showed no significant difference. It was found that the inclusion of eight transducers made possible a more accurate record of oral muscular activity than has been possible previously and it is confirmed that the subjects selected showed considerable ability to adapt to changes in denture profile

Design and manufacturing of advanced composite aircraft structures using automated tow placement

Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management; and, Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1996.Includes bibliographical references (leaves 89-91).by Ian B. Land.S.M

Filament winding machine control using B-spline interpolation

Filament winding is a process for the placement of reinforcement fibres on to a rotating surface in a specified geometric pattern. A conventional straight line interpolation controller is not very appropriate for filament winding because the fibre pay-out-eye is at some distance away from the mandrel surface and its movement from one point to another may disturb the position of previously laid fibre on the mandrel. Filament winding demands a controller which can produce fast and smooth carriage movements, and have a path-anticipation capability so that while moving around curves the effect of pay-out-eye movement on previous fibre positions is minimised. This problem can be overcome by using an interpolation technique which determines the pay-out-eye path by considering more than two data points, and whose profile is continuous in nature up to its second derivative. In this project an IDM PC based filament winding controller, using B-spline interpolation technique, is developed. To test the performance of the controller a 3-axis CNC filament winding machine was designed and manufactured. For optimum performance, emphasis was given to the low inertia of the machine carriage, while at the same time maintaining the system's structural stiffness. To reduce the machine carriage weight, the DC servomotors were installed on the machine's frame, instead of the carriage, and a timing belt arrangement was used for power transmission. The controller's electronic hardware was assembled using servo amplifiers, DAC cards, and a purpose built optical encoder interface card. The controller software was developed using TURBO C++ as the main programming language, whereas the hardware interface routines were written in Assembly Language. Problems of winding path deviation as a result of B-spline approximation were tackled using knowledge based programming techniques. The results showed a considerable improvement in winding speed and less fibre slippage in the case of non-geodesic winding patterns, resulting in higher accuracy of fibre placement on the mandrel

Filament winding machine control using B-spline interpolation

Filament winding is a process for the placement of reinforcement fibres on to a rotating surface in a specified geometric pattern. A conventional straight line interpolation controller is not very appropriate for filament winding because the fibre pay-out-eye is at some distance away from the mandrel surface and its movement from one point to another may disturb the position of previously laid fibre on the mandrel. Filament winding demands a controller which can produce fast and smooth carriage movements, and have a path-anticipation capability so that while moving around curves the effect of pay-out-eye movement on previous fibre positions is minimised. This problem can be overcome by using an interpolation technique which determines the pay-out-eye path by considering more than two data points, and whose profile is continuous in nature up to its second derivative. In this project an IDM PC based filament winding controller, using B-spline interpolation technique, is developed. To test the performance of the controller a 3-axis CNC filament winding machine was designed and manufactured. For optimum performance, emphasis was given to the low inertia of the machine carriage, while at the same time maintaining the system's structural stiffness. To reduce the machine carriage weight, the DC servomotors were installed on the machine's frame, instead of the carriage, and a timing belt arrangement was used for power transmission. The controller's electronic hardware was assembled using servo amplifiers, DAC cards, and a purpose built optical encoder interface card. The controller software was developed using TURBO C++ as the main programming language, whereas the hardware interface routines were written in Assembly Language. Problems of winding path deviation as a result of B-spline approximation were tackled using knowledge based programming techniques. The results showed a considerable improvement in winding speed and less fibre slippage in the case of non-geodesic winding patterns, resulting in higher accuracy of fibre placement on the mandrel

The Impact of Change in Self-Compassion, Psychological Inflexibility, and Interpersonal Courage in PSTD Treatment

Despite numerous advances in the field’s understanding of the development and maintenance of posttraumatic stress disorder (PTSD), current treatments are often limited in effectiveness due to a narrow focus on symptom reduction (Cloitre, 2015; Yehuda et al., 2015). One reason for this issue is that the impact of PTSD extends into areas such as interpersonal relationships, pursuit of valued activities, and acceptance of the self (Cloitre, 2015). These processes appear to be especially relevant in chronic/complex PTSD, which is rarely represented in controlled trials (Cloitre, Miranda, Stovall- McClough, & Han, 2005). As such, PTSD research with an expanded focus beyond symptom reduction, especially research conducted in clinical settings, is likely to be especially relevant to both PTSD researchers and clinicians working in the field. To that end, this study examined the impact of change in self-compassion, psychological inflexibility, and interpersonal courage on PTSD symptom reduction, trauma-related shame, quality of life, and valued living in an exposure-based PTSD partial hospitalization program (n = 537; 75% White; 83% Female; mean age = 36). Latent growth curves, including intercepts and slopes (linear, quadratic, cubic, and spline), were estimated for all variables under study. All measures except for interpersonal courage showed clinically meaningful change over the course of the program. At p \u3c .001, latent regressions showed that only admission psychological inflexibility scores predicted discharge PTSD symptoms and that only admission interpersonal courage (p = .032) was related to discharge quality of life. For the latent growth curves, three-piece spline models were retained for PTSD symptoms, self-compassion, and valued living. Linear models were retained for psychological inflexibility, quality of life, interpersonal courage, and trauma-related shame. For the three PTSD slopes and three valued living slopes, only the three self-compassion slopes were significant predictors (p \u3c .001). The psychological inflexibility slope predicted both the quality of life slope (p \u3c .001), while the interpersonal courage slope predicted the trauma-related shame slope (p \u3c .001). Results demonstrate that focusing on processes such as psychological inflexibility, self compassion, and interpersonal courage might increase the efficacy of PTSD treatment in addressing the broad range of concerns present in the disorder

Aspects of the mechanical behaviour of spiral wire structures relating to quasi static and fatigue properties.

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