Damage initiation and growth under compression-compression fatigue loading were investigated for a stitched uniweave material system with an underlying AS4/3501-6 quasi-isotropic layup. Performance of unnotched specimens having stitch rows at either 0° or 90° to the loading direction was compared. Special attention was given to the effects of stitching-related manufacturing defects. Damage evaluation techniques included edge replication, stiffness monitoring, X-ray radiography, residual compressive strength, and laminate sectioning. It was found that the manufacturing defect of inclined stitches had the greatest adverse effect on material performance. 0° and 90° specimen performances were generally the same. While the stitches were the source of damage initiation, they also slowed damage propagation both along the length and across the width and affected through the thickness damage growth. A pinched layer zone formed by the stitches particularly affected damage initiation and growth. The compression failure mode was transverse shear for all specimens, both in static compression and fatigue cycling tests. Specimens without stitches were not available for comparison. / Master of Science

As the most commonly diseased valve of the heart, the mitral valve has been the subject of extensive research for many years. Prior research has focused on the development of surgical repair techniques and mainly consists of in vivo clinical studies into the efficacy and long-term effects of different procedures. There is a need for a means of studying the mitral valve ex vivo, incorporating patient data and the effects of different repair techniques on the valve prior to surgery. In this study, a method was developed for reconstructing the mitral valve from patient-specific data. Three-dimensional transthoracic and transesophageal echocardiography (3D-TTE and 3D-TEE) were used to obtain ultrasound images from a normal subject and a patient with mitral valve regurgitation. Geometric information was extracted from the images defining the primary structures of the mitral valve and a special program in MATLAB was created to automatically construct a finite element model of a valve. A dynamic finite element analysis solver, LS-DYNA 971, was used to simulate the dynamics of the valves and the non-linear, anisotropic behaviour of biological tissue. The two models were successful in simulating the dynamics of the mitral valve, with the subject model displaying normal function and the patient model showing the dysfunction displayed in the ultrasound images. A method was then developed to modify the original patient model, in a way that maintains its patient-specific nature, to model mitral valve repair. Four mitral valve repair techniques were simulated using the patient model: the annuloplasty ring, the double-orifice Alfieri stitch, the paracommissural Alfieri stitch, and the quadrangular resection. The former was coupled with the other three techniques, as is standard protocol in mitral valve repair. The effects of these techniques on the mitral valve were successfully determined, with varying degrees of improvement in valve function.

As the most commonly diseased valve of the heart, the mitral valve has been the subject of extensive research for many years. Prior research has focused on the development of surgical repair techniques and mainly consists of in vivo clinical studies into the efficacy and long-term effects of different procedures. There is a need for a means of studying the mitral valve ex vivo, incorporating patient data and the effects of different repair techniques on the valve prior to surgery. In this study, a method was developed for reconstructing the mitral valve from patient-specific data. Three-dimensional transthoracic and transesophageal echocardiography (3D-TTE and 3D-TEE) were used to obtain ultrasound images from a normal subject and a patient with mitral valve regurgitation. Geometric information was extracted from the images defining the primary structures of the mitral valve and a special program in MATLAB was created to automatically construct a finite element model of a valve. A dynamic finite element analysis solver, LS-DYNA 971, was used to simulate the dynamics of the valves and the non-linear, anisotropic behaviour of biological tissue. The two models were successful in simulating the dynamics of the mitral valve, with the subject model displaying normal function and the patient model showing the dysfunction displayed in the ultrasound images. A method was then developed to modify the original patient model, in a way that maintains its patient-specific nature, to model mitral valve repair. Four mitral valve repair techniques were simulated using the patient model: the annuloplasty ring, the double-orifice Alfieri stitch, the paracommissural Alfieri stitch, and the quadrangular resection. The former was coupled with the other three techniques, as is standard protocol in mitral valve repair. The effects of these techniques on the mitral valve were successfully determined, with varying degrees of improvement in valve function.

As the most commonly diseased valve of the heart, the mitral valve has been the subject of extensive research for many years. Prior research has focused on the development of surgical repair techniques and mainly consists of in vivo clinical studies into the efficacy and long-term effects of different procedures. There is a need for a means of studying the mitral valve ex vivo, incorporating patient data and the effects of different repair techniques on the valve prior to surgery. In this study, a method was developed for reconstructing the mitral valve from patient-specific data. Three-dimensional transthoracic and transesophageal echocardiography (3D-TTE and 3D-TEE) were used to obtain ultrasound images from a normal subject and a patient with mitral valve regurgitation. Geometric information was extracted from the images defining the primary structures of the mitral valve and a special program in MATLAB was created to automatically construct a finite element model of a valve. A dynamic finite element analysis solver, LS-DYNA 971, was used to simulate the dynamics of the valves and the non-linear, anisotropic behaviour of biological tissue. The two models were successful in simulating the dynamics of the mitral valve, with the subject model displaying normal function and the patient model showing the dysfunction displayed in the ultrasound images. A method was then developed to modify the original patient model, in a way that maintains its patient-specific nature, to model mitral valve repair. Four mitral valve repair techniques were simulated using the patient model: the annuloplasty ring, the double-orifice Alfieri stitch, the paracommissural Alfieri stitch, and the quadrangular resection. The former was coupled with the other three techniques, as is standard protocol in mitral valve repair. The effects of these techniques on the mitral valve were successfully determined, with varying degrees of improvement in valve function.

Mit multiaxialen Gelegen auf Basis der Kettenwirktechnik stehen hervorragende textile Halbzeuge für die Weiterverarbeitung als Verstärkungskomponente in Faser-Kunststoff-Verbunden zur Verfügung. Die bisherige Konfiguration der für die Herstellung dieser Textilien verwendeten Nähwirkmaschinen führt verfahrensbedingt zu einem unsymmetrischen Produktaufbau mit üblicherweise nur einer Fadenlage in Gelegelängsrichtung und ebenso zu Einschränkungen bei der Anordnung des Bindefadens im Textil. Durch die Erweiterung des Nähwirkprozesses wird es möglich, Nähwirkstoffe mit einer beliebigen Abfolge der Einzellagen herzustellen, zum Beispiel in symmetrischer Anordnung. Die neuen Varianten der Lagenanordnung und der Bindungskonstruktion bilden den Ausgangspunkt für die Produktentwicklung am Beispiel zweier Anwendungen aus den Bereichen der Faser-Kunststoff-Verbunde und des textilbewehrten Betons. Hier wird deutlich, dass über die Herstellung symmetrischer Gelege hinaus der Einsatz des erweiterten Wirkprozesses die Eigenschaften der Gelege und der Endprodukte vorteilhaft beeinflussen kann. Aus den untersuchten Beispielen und grundsätzlichen Betrachtungen leitet sich ab, unter welchen maschinentechnischen Voraussetzungen der Einsatz des erweiterten Wirkprozesses sinnvoll ist. Es wird ein Konzept entwickelt, auf dessen Grundlage Nähwirkstoffe mit variabler Lagenanordnung auf Nähwirkmaschinen gefertigt werden können. / Multiaxial multi-ply fabrics made by warp knitting are excellently suited for the application in fiber reinforced composites. The usual configuration of the stitch-bonding machines, which are used to produce these fabrics, necessarily leads to composite laminates with an asymmetric layer arrangement and only one layer of yarns in the zero degree direction of the fabric. The variability of patterning with the binding yarn is also limited. By completing the stitch-bonding process with an additional work step it is possible to produce stitch-bonded fabrics without any restrictions concerning the arrangement of the individual layers in the fabric, for example with a symmetric composition. This is the basis for the development of two exemplary products in the fields of textile reinforced plastics and textile reinforced concrete. It can be shown that the application of the extended stitch-bonding process is advantageous beyond the layer arrangement, positively affecting the mechanical properties of the fabric and the composite. From these examples, conclusions are drawn regarding the configuration of future stitch-bonding machines.

Mit multiaxialen Gelegen auf Basis der Kettenwirktechnik stehen hervorragende textile Halbzeuge für die Weiterverarbeitung als Verstärkungskomponente in Faser-Kunststoff-Verbunden zur Verfügung. Die bisherige Konfiguration der für die Herstellung dieser Textilien verwendeten Nähwirkmaschinen führt verfahrensbedingt zu einem unsymmetrischen Produktaufbau mit üblicherweise nur einer Fadenlage in Gelegelängsrichtung und ebenso zu Einschränkungen bei der Anordnung des Bindefadens im Textil. Durch die Erweiterung des Nähwirkprozesses wird es möglich, Nähwirkstoffe mit einer beliebigen Abfolge der Einzellagen herzustellen, zum Beispiel in symmetrischer Anordnung. Die neuen Varianten der Lagenanordnung und der Bindungskonstruktion bilden den Ausgangspunkt für die Produktentwicklung am Beispiel zweier Anwendungen aus den Bereichen der Faser-Kunststoff-Verbunde und des textilbewehrten Betons. Hier wird deutlich, dass über die Herstellung symmetrischer Gelege hinaus der Einsatz des erweiterten Wirkprozesses die Eigenschaften der Gelege und der Endprodukte vorteilhaft beeinflussen kann. Aus den untersuchten Beispielen und grundsätzlichen Betrachtungen leitet sich ab, unter welchen maschinentechnischen Voraussetzungen der Einsatz des erweiterten Wirkprozesses sinnvoll ist. Es wird ein Konzept entwickelt, auf dessen Grundlage Nähwirkstoffe mit variabler Lagenanordnung auf Nähwirkmaschinen gefertigt werden können. / Multiaxial multi-ply fabrics made by warp knitting are excellently suited for the application in fiber reinforced composites. The usual configuration of the stitch-bonding machines, which are used to produce these fabrics, necessarily leads to composite laminates with an asymmetric layer arrangement and only one layer of yarns in the zero degree direction of the fabric. The variability of patterning with the binding yarn is also limited. By completing the stitch-bonding process with an additional work step it is possible to produce stitch-bonded fabrics without any restrictions concerning the arrangement of the individual layers in the fabric, for example with a symmetric composition. This is the basis for the development of two exemplary products in the fields of textile reinforced plastics and textile reinforced concrete. It can be shown that the application of the extended stitch-bonding process is advantageous beyond the layer arrangement, positively affecting the mechanical properties of the fabric and the composite. From these examples, conclusions are drawn regarding the configuration of future stitch-bonding machines.

Background: Aortic valve insufficiency (AI) at the time of left ventricular assist device (LVAD) insertion needs to be corrected, however there is little known about how to manage bioprosthetic valvular AI. Case presentation: A 55-year-old female with dilated cardiomyopathy who previously had a bioprosthetic aortic valve replacement needed a LVAD as a bridge to transplant. Her left ventricular ejection fraction was 10% and had mild to moderate transvalvular AI. She underwent a HeartWare HVAD insertion along with aortic valvular coaptation stitch repair (Park's stitch) to the bioprosthetic valve. Conclusion: Her AI improved to trivial with minimal ejection through the bioprosthetic valve. She was transplanted 6 months following the surgery. A Park's stitch to the bioprosthetic aortic valve with more than mild AI might be a good option for bridge to transplant patient.

This report contains discussion of four design projects aimed to investigate the ability of handicrafts to communicate complicated subject matter. In this exploration, handicrafts are used to present the experience of recovering from a traumatic experience by challenging commonly held stereotypes about handicrafts. By breaking the trauma and recovery process into four distinct stages, each stage can be discussed in detail via the corresponding design piece. Consequently, each stage also allows for new opportunities to apply handicraft practices in new ways. Through this line of questioning, the four pieces expand upon the imagery, materiality, subject matter, and formal creation techniques typically used in handicraft projects. This collection adds to a greater body of work that intersects traumatic experiences with art and design and that explores the power of design as a communication tool. It opens the door for further investigation into the application’s potential as a teaching tool for trauma victims, nontraditional applications of the craft, its ability to aid in the recovery process, and the potential risk and benefit victims have from such work being done and from creating such pieces themselves. / text

This project grew out of an interest in notions of ‘home’, what ‘home’ is and its relationship to the ‘house’ as a physical place of dwelling. Specifically, this project explores how the home is represented in vernacular image-making, such as the photographs in the family album and craft methods such as cross-stitch. This lead to an investigation into vernacular photography, collections and archives, and contemporary craft methods. An archive of photographs collected follows the text, as well as drawings and embroideries made during the project. The final work consists of a large-scale projection of a cross-stitch and the photograph it originated from.

This paper is the supporting document for the Master of Fine Arts exhibition, The Door in the Threshold, held in the Slocumb Galleries at East Tennessee State University from March 15-19, 2010. The exhibition contains twelve pieces of artwork, mounted on the wall. The paper expands upon such themes as memory and family as explored by the work in the gallery. The title of both the paper and show reference the impact of my Armenian heritage on my creative process. Doors in Armenian folklore were sacred places containing the threshold to the spiritual. Thus, my pieces are meant to become doors to the threshold of my past. Also discussed in the paper are the influence of the quilt form and connections to the work of artists Arshile Gorky, Whitfield Lovell, and Karen Hampton.