A new optimal seam method for seamless image stitching

NASA Astrophysics Data System (ADS)

Xue, Jiale; Chen, Shengyong; Cheng, Xu; Han, Ying; Zhao, Meng

2017-07-01

A novel optimal seam method which aims to stitch those images with overlapping area more seamlessly has been propos ed. Considering the traditional gradient domain optimal seam method and fusion algorithm result in bad color difference measurement and taking a long time respectively, the input images would be converted to HSV space and a new energy function is designed to seek optimal stitching path. To smooth the optimal stitching path, a simplified pixel correction and weighted average method are utilized individually. The proposed methods exhibit performance in eliminating the stitching seam compared with the traditional gradient optimal seam and high efficiency with multi-band blending algorithm.

Efficient Design and Analysis of Lightweight Reinforced Core Sandwich and PRSEUS Structures

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.; Yarrington, Phillip W.; Lucking, Ryan C.; Collier, Craig S.; Ainsworth, James J.; Toubia, Elias A.

2012-01-01

Design, analysis, and sizing methods for two novel structural panel concepts have been developed and incorporated into the HyperSizer Structural Sizing Software. Reinforced Core Sandwich (RCS) panels consist of a foam core with reinforcing composite webs connecting composite facesheets. Boeing s Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) panels use a pultruded unidirectional composite rod to provide axial stiffness along with integrated transverse frames and stitching. Both of these structural concepts are ovencured and have shown great promise applications in lightweight structures, but have suffered from the lack of efficient sizing capabilities similar to those that exist for honeycomb sandwich, foam sandwich, hat stiffened, and other, more traditional concepts. Now, with accurate design methods for RCS and PRSEUS panels available in HyperSizer, these concepts can be traded and used in designs as is done with the more traditional structural concepts. The methods developed to enable sizing of RCS and PRSEUS are outlined, as are results showing the validity and utility of the methods. Applications include several large NASA heavy lift launch vehicle structures.

Failure at Frame-Stringer Intersections in PRSEUS Panels

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.

2012-01-01

NASA, the Air Force Research Laboratory and The Boeing Company have worked to develop new low-cost, light-weight composite structures for aircraft. A Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept has been developed which offers advantages over traditional metallic structures. In this concept a stitched carbon-epoxy material system has been developed with the potential for reducing the weight and cost of transport aircraft structure by eliminating fasteners, thereby reducing part count and labor. By adding unidirectional carbon rods to the top of stiffeners, the panel becomes more structurally efficient. This combination produces a more damage tolerant design. This study focuses on the intersection between the rod-stiffener and the foam-filled frame in a PRSEUS specimen. Compression loading is considered, which induces stress concentrations at the intersection point that can lead to failures. An experiment with accompanying analysis for a single-frame specimen is described, followed by a parametric study of simple reinforcements to reduce strains in the intersection region.

Damage Arresting Composites for Shaped Vehicles - Phase II Final Report

NASA Technical Reports Server (NTRS)

Velicki, Alex; Yovanof, Nicolette; Baraja, Jaime; Linton, Kim; Li, Victor; Hawley, Arthur; Thrash, Patrick; DeCoux, Steve; Pickell, Robert

2011-01-01

This report describes the development of a novel structural concept, Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body (BWB) airplane configuration. In addition to the analytical studies, a three specimen test program was also completed to assess the concept under axial tension loading, axial compression loading, and internal pressure loading.

Dark-field microscopic image stitching method for surface defects evaluation of large fine optics.

PubMed

Liu, Dong; Wang, Shitong; Cao, Pin; Li, Lu; Cheng, Zhongtao; Gao, Xin; Yang, Yongying

2013-03-11

One of the challenges in surface defects evaluation of large fine optics is to detect defects of microns on surfaces of tens or hundreds of millimeters. Sub-aperture scanning and stitching is considered to be a practical and efficient method. But since there are usually few defects on the large aperture fine optics, resulting in no defects or only one run-through line feature in many sub-aperture images, traditional stitching methods encounter with mismatch problem. In this paper, a feature-based multi-cycle image stitching algorithm is proposed to solve the problem. The overlapping areas of sub-apertures are categorized based on the features they contain. Different types of overlapping areas are then stitched in different cycles with different methods. The stitching trace is changed to follow the one that determined by the features. The whole stitching procedure is a region-growing like process. Sub-aperture blocks grow bigger after each cycle and finally the full aperture image is obtained. Comparison experiment shows that the proposed method is very suitable to stitch sub-apertures that very few feature information exists in the overlapping areas and can stitch the dark-field microscopic sub-aperture images very well.

An efficient auto TPT stitch guidance generation for optimized standard cell design

NASA Astrophysics Data System (ADS)

Samboju, Nagaraj C.; Choi, Soo-Han; Arikati, Srini; Cilingir, Erdem

2015-03-01

As the technology continues to shrink below 14nm, triple patterning lithography (TPT) is a worthwhile lithography methodology for printing dense layers such as Metal1. However, this increases the complexity of standard cell design, as it is very difficult to develop a TPT compliant layout without compromising on the area. Hence, this emphasizes the importance to have an accurate stitch generation methodology to meet the standard cell area requirement as defined by the technology shrink factor. In this paper, we present an efficient auto TPT stitch guidance generation technique for optimized standard cell design. The basic idea here is to first identify the conflicting polygons based on the Fix Guidance [1] solution developed by Synopsys. Fix Guidance is a reduced sub-graph containing minimum set of edges along with the connecting polygons; by eliminating these edges in a design 3-color conflicts can be resolved. Once the conflicting polygons are identified using this method, they are categorized into four types [2] - (Type 1 to 4). The categorization is based on number of interactions a polygon has with the coloring links and the triangle loops of fix guidance. For each type a certain criteria for keep-out region is defined, based on which the final stitch guidance locations are generated. This technique provides various possible stitch locations to the user and helps the user to select the best stitch location considering both design flexibility (max. pin access/small area) and process-preferences. Based on this technique, a standard cell library for place and route (P and R) can be developed with colorless data and a stitch marker defined by designer using our proposed method. After P and R, the full chip (block) would contain the colorless data and standard cell stitch markers only. These stitch markers are considered as "must be stitch" candidates. Hence during full chip decomposition it is not required to generate and select the stitch markers again for the complete data; therefore, the proposed method reduces the decomposition time significantly.

Local facet approximation for image stitching

NASA Astrophysics Data System (ADS)

Li, Jing; Lai, Shiming; Liu, Yu; Wang, Zhengming; Zhang, Maojun

2018-01-01

Image stitching aims at eliminating multiview parallax and generating a seamless panorama given a set of input images. This paper proposes a local adaptive stitching method, which could achieve both accurate and robust image alignments across the whole panorama. A transformation estimation model is introduced by approximating the scene as a combination of neighboring facets. Then, the local adaptive stitching field is constructed using a series of linear systems of the facet parameters, which enables the parallax handling in three-dimensional space. We also provide a concise but effective global projectivity preserving technique that smoothly varies the transformations from local adaptive to global planar. The proposed model is capable of stitching both normal images and fisheye images. The efficiency of our method is quantitatively demonstrated in the comparative experiments on several challenging cases.

PRSEUS Structural Concept Development

NASA Technical Reports Server (NTRS)

Velicki, Alex; Jegley, Dawn

2014-01-01

A lighter, more robust airframe is one of the key technological advancements necessary for the successful launch of any large next-generation transport aircraft. Such a premise dictates that considerable improvements beyond current state-of-the-art aluminum structures is needed, and that improvements of this magnitude will require an extensive use of composite materials that are not only lightweight, but also economical to produce. To address this challenge, researchers at NASA and The Boeing Company are developing a novel structural concept called the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) under the Environmentally Responsible Aviation (ERA) Project. It is an integrally stiffened panel concept that is stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. In addition to improved structural performance, an important facet of this unique arrangement of stitched carbon fibers is its innovative manufacturing method that has the potential to lower fabrication costs by eliminating fasteners and autoclave cures. The rationale and development status for this new approach forms the basis of the work described in this paper. The test specimens described herein were fabricated, or are currently being fabricated, by The Boeing Company, while the structural analyses and testing tasks are being performed by NASA and Boeing personnel.

Vibroacoustic Characterization of a New Hybrid Wing-Body Fuselage Concept

NASA Technical Reports Server (NTRS)

Allen, Albert R.; Przekop, Adam

2012-01-01

A lighter, more robust airframe design is required to withstand the loading inherent to next generation non cylindrical commercial airliners. The Pultruded Rod Stitched Efficient Unitized Structure concept, a highly integrated composite design involving a stitched and co-cured substructure, has been developed to meet such requirements. While this structure has been shown to meet the demanding out-of-plane loading requirements of the flat-sided pressurized cabin design, there are concerns that the stiff co-cured details will result in relatively high acoustic radiation efficiencies at frequencies well below the thin skin acoustic coincidence frequency. To address this concern and establish a set of baseline vibroacoustic characteristics, a representative test panel was fabricated and a suite of tests were conducted that involved measurements of panel vibration and radiated sound power during point force and diffuse acoustic field excitations. Experimental results are shown and compared with Finite Element and Statistical Energy Analysis model predictions through the use of modal and energy correlation techniques among others. The behavior of the structure subject to turbulent boundary layer excitation is also numerically examined.

Initial Evaluation of Acoustic Emission SHM of PRSEUS Multi-bay Box Tests

NASA Technical Reports Server (NTRS)

Horne, Michael R.; Madaras, Eric I.

2016-01-01

A series of tests of the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) HWB Multi-Bay Test Article were conducted during the second quarter of 2015 at NASA Langley Research Center (LaRC) in the Combined Loads Test facility (COLTS). This report documents the Acoustic Emission (AE) data collected during those tests along with an initial analysis of the data. A more detailed analysis will be presented in future publications.

TeraStitcher - A tool for fast automatic 3D-stitching of teravoxel-sized microscopy images

PubMed Central

2012-01-01

Background Further advances in modern microscopy are leading to teravoxel-sized tiled 3D images at high resolution, thus increasing the dimension of the stitching problem of at least two orders of magnitude. The existing software solutions do not seem adequate to address the additional requirements arising from these datasets, such as the minimization of memory usage and the need to process just a small portion of data. Results We propose a free and fully automated 3D Stitching tool designed to match the special requirements coming out of teravoxel-sized tiled microscopy images that is able to stitch them in a reasonable time even on workstations with limited resources. The tool was tested on teravoxel-sized whole mouse brain images with micrometer resolution and it was also compared with the state-of-the-art stitching tools on megavoxel-sized publicy available datasets. This comparison confirmed that the solutions we adopted are suited for stitching very large images and also perform well on datasets with different characteristics. Indeed, some of the algorithms embedded in other stitching tools could be easily integrated in our framework if they turned out to be more effective on other classes of images. To this purpose, we designed a software architecture which separates the strategies that use efficiently memory resources from the algorithms which may depend on the characteristics of the acquired images. Conclusions TeraStitcher is a free tool that enables the stitching of Teravoxel-sized tiled microscopy images even on workstations with relatively limited resources of memory (<8 GB) and processing power. It exploits the knowledge of approximate tile positions and uses ad-hoc strategies and algorithms designed for such very large datasets. The produced images can be saved into a multiresolution representation to be efficiently retrieved and processed. We provide TeraStitcher both as standalone application and as plugin of the free software Vaa3D. PMID:23181553

32 CFR 507.3 - Explanation of abbreviations and terms.

Code of Federal Regulations, 2010 CFR

2010-07-01

... OF HERALDIC DESIGNS AND HERALDIC QUALITY CONTROL PROGRAM Introduction § 507.3 Explanation of... times actual size, showing placement of stitches, color and size of yarn and number of stitches. (2... items worn on the uniform to indicate unit, skill, branch, award or identification and a design has been...

Assessment of Damage Containment Features of a Full-Scale PRSEUS Fuselage Panel Through Test and Teardown

NASA Technical Reports Server (NTRS)

Bergan, Andrew C.; Bakuckas, John G., Jr.; Lovejoy, Andrew E.; Jegley, Dawn C.; Awerbuch, Jonathan; Tan, Tein-Min

2012-01-01

An area that shows promise in enhancing structural integrity of aircraft and aerospace structures is the integrally stitched composite technology. The most recent generation of this technology is the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept developed by Boeing Research and Technology and the National Aeronautics and Space Administration. A joint test program on the assessment of damage containment capabilities of the PRSEUS concept for curved fuselage structures was conducted recently at the Federal Aviation Administration William J. Hughes Technical Center. The panel was subjected to axial tension, internal pressure, and combined axial tension and internal pressure load conditions up to fracture, with a through-the-thickness, two-bay notch severing the central stiffener. For the purpose of future progressive failure analysis development and verification, extensive post failure nondestructive and teardown inspections were conducted. Detailed inspections were performed directly ahead of the notch tip where stable damage progression was observed. These examinations showed: 1) extensive delaminations developed ahead of the notch tip, 2) the extent and location of damage, 3) the typical damage mechanisms observed in composites, and 4) the role of stitching and warp-knitting in the failure mechanisms. The objective of this paper is to provide a summary of results from these posttest inspections.

NDE evidence for the damage arrestment performance of PRSEUS composite cube during high-pressure load test

NASA Astrophysics Data System (ADS)

Johnston, Patrick H.; Parker, F. Raymond

2014-02-01

As an approach to light-weight, cost-effective and manufacturable structures required to enable the hybrid wing body aircraft, The Boeing Company, Inc. and NASA have developed the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. A PRSEUS pressure cube was developed as a risk reduction test article to examine a new integral cap joint concept as part of a building block approach for technology development of the PRSEUS concept. The overall specimen strength exceeded the 18.4 psi load requirement as testing resulted in the cube reaching a final pressure load of around 48 psi prior to catastrophic failure. The cube pressure test verified that the joints and structure were capable of sustaining the required loads, and represented the first testing of joined PRSEUS structure. This paper will address the damage arrestment performance of the stitched PRSEUS structure. Following catastrophic failure of the cube, ultrasonic pulse-echo inspection found that the localized damage, surrounding a barely-visible impact damage site, did not change noticeably between just after impact and catastrophic failure of the cube, and did not play a role in the catastrophic failure event. Ultrasonic inspection of the remaining intact cube panels presented three basic types of indications: delaminations between laminae parallel to the face sheets, lying between face sheet and tear strap layers, or between tear strap and flange layers; delaminations above the noodles of stringers, frames or integral caps, lying within face sheet or tear strap layers; and delaminations between the laminae in the inner fillets of the integral caps, where pulloff stresses were expected to be highest. Delaminations of all three types were predominantly contained by the first row of stitches encountered. For the small fraction of delaminations extending beyond the first row of stitches, all were contained by the second stitch row.

NDE Evidence for the Damage Arrestment Performance of PRSEUS Composite Cube During High-Pressure Load Test

NASA Technical Reports Server (NTRS)

Johnston, Patrick H.; Parker, F. Raymond

2013-01-01

As an approach to light-weight, cost-effective and manufacturable structures required to enable the hybrid wing body aircraft, The Boeing Company, Inc. and NASA have developed the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. A PRSEUS pressure cube was developed as a risk reduction test article to examine a new integral cap joint concept as part of a building block approach for technology development of the PRSEUS concept. The overall specimen strength exceeded the 18.4 psi load requirement as testing resulted in the cube reaching a final pressure load of around 48 psi prior to catastrophic failure. The cube pressure test verified that the joints and structure were capable of sustaining the required loads, and represented the first testing of joined PRSEUS structure. This paper will address the damage arrestment performance of the stitched PRSEUS structure. Following catastrophic failure of the cube, ultrasonic pulse-echo inspection found that the localized damage, surrounding a barely-visible impact damage site, did not change noticeably between just after impact and catastrophic failure of the cube, and did not play a role in the catastrophic failure event. Ultrasonic inspection of the remaining intact cube panels presented three basic types of indications: delaminations between laminae parallel to the face sheets, lying between face sheet and tear strap layers, or between tear strap and flange layers; delaminations above the noodles of stringers, frames or integral caps, lying within face sheet or tear strap layers; and delaminations between the laminae in the inner fillets of the integral caps, where pulloff stresses were expected to be highest. Delaminations of all three types were predominantly contained by the first row of stitches encountered. For the small fraction of delaminations extending beyond the first row of stitches, all were contained by the second stitch row.

The algorithm of fast image stitching based on multi-feature extraction

NASA Astrophysics Data System (ADS)

Yang, Chunde; Wu, Ge; Shi, Jing

2018-05-01

This paper proposed an improved image registration method combining Hu-based invariant moment contour information and feature points detection, aiming to solve the problems in traditional image stitching algorithm, such as time-consuming feature points extraction process, redundant invalid information overload and inefficiency. First, use the neighborhood of pixels to extract the contour information, employing the Hu invariant moment as similarity measure to extract SIFT feature points in those similar regions. Then replace the Euclidean distance with Hellinger kernel function to improve the initial matching efficiency and get less mismatching points, further, estimate affine transformation matrix between the images. Finally, local color mapping method is adopted to solve uneven exposure, using the improved multiresolution fusion algorithm to fuse the mosaic images and realize seamless stitching. Experimental results confirm high accuracy and efficiency of method proposed in this paper.

Histostitcher™: An informatics software platform for reconstructing whole-mount prostate histology using the extensible imaging platform framework

PubMed Central

Toth, Robert J.; Shih, Natalie; Tomaszewski, John E.; Feldman, Michael D.; Kutter, Oliver; Yu, Daphne N.; Paulus, John C.; Paladini, Ginaluca; Madabhushi, Anant

2014-01-01

Context: Co-registration of ex-vivo histologic images with pre-operative imaging (e.g., magnetic resonance imaging [MRI]) can be used to align and map disease extent, and to identify quantitative imaging signatures. However, ex-vivo histology images are frequently sectioned into quarters prior to imaging. Aims: This work presents Histostitcher™, a software system designed to create a pseudo whole mount histology section (WMHS) from a stitching of four individual histology quadrant images. Materials and Methods: Histostitcher™ uses user-identified fiducials on the boundary of two quadrants to stitch such quadrants. An original prototype of Histostitcher™ was designed using the Matlab programming languages. However, clinical use was limited due to slow performance, computer memory constraints and an inefficient workflow. The latest version was created using the extensible imaging platform (XIP™) architecture in the C++ programming language. A fast, graphics processor unit renderer was designed to intelligently cache the visible parts of the histology quadrants and the workflow was significantly improved to allow modifying existing fiducials, fast transformations of the quadrants and saving/loading sessions. Results: The new stitching platform yielded significantly more efficient workflow and reconstruction than the previous prototype. It was tested on a traditional desktop computer, a Windows 8 Surface Pro table device and a 27 inch multi-touch display, with little performance difference between the different devices. Conclusions: Histostitcher™ is a fast, efficient framework for reconstructing pseudo WMHS from individually imaged quadrants. The highly modular XIP™ framework was used to develop an intuitive interface and future work will entail mapping the disease extent from the pseudo WMHS onto pre-operative MRI. PMID:24843820

Video auto stitching in multicamera surveillance system

NASA Astrophysics Data System (ADS)

He, Bin; Zhao, Gang; Liu, Qifang; Li, Yangyang

2012-01-01

This paper concerns the problem of video stitching automatically in a multi-camera surveillance system. Previous approaches have used multiple calibrated cameras for video mosaic in large scale monitoring application. In this work, we formulate video stitching as a multi-image registration and blending problem, and not all cameras are needed to be calibrated except a few selected master cameras. SURF is used to find matched pairs of image key points from different cameras, and then camera pose is estimated and refined. Homography matrix is employed to calculate overlapping pixels and finally implement boundary resample algorithm to blend images. The result of simulation demonstrates the efficiency of our method.

Video auto stitching in multicamera surveillance system

NASA Astrophysics Data System (ADS)

He, Bin; Zhao, Gang; Liu, Qifang; Li, Yangyang

2011-12-01

This paper concerns the problem of video stitching automatically in a multi-camera surveillance system. Previous approaches have used multiple calibrated cameras for video mosaic in large scale monitoring application. In this work, we formulate video stitching as a multi-image registration and blending problem, and not all cameras are needed to be calibrated except a few selected master cameras. SURF is used to find matched pairs of image key points from different cameras, and then camera pose is estimated and refined. Homography matrix is employed to calculate overlapping pixels and finally implement boundary resample algorithm to blend images. The result of simulation demonstrates the efficiency of our method.

Testing of a Stitched Composite Large-Scale Multi-Bay Pressure Box

NASA Technical Reports Server (NTRS)

Jegley, Dawn; Rouse, Marshall; Przekop, Adam; Lovejoy, Andrew

2016-01-01

NASA has created the Environmentally Responsible Aviation (ERA) Project to develop technologies to reduce aviation's impact on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe to enable the introduction of unconventional aircraft configurations. NASA and The Boeing Company have worked together to develop a structural concept that is lightweight and an advancement beyond state-of-the-art composite structures. The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is an integrally stiffened panel design where elements are stitched together. The PRSEUS concept is designed to maintain residual load carrying capabilities under a variety of damage scenarios. A series of building block tests were evaluated to explore the fundamental assumptions related to the capability and advantages of PRSEUS panels. The final step in the building block series is an 80%-scale pressure box representing a portion of the center section of a Hybrid Wing Body (HWB) transport aircraft. The testing of this article under maneuver load and internal pressure load conditions is the subject of this paper. The experimental evaluation of this article, along with the other building block tests and the accompanying analyses, has demonstrated the viability of a PRSEUS center body for the HWB vehicle. Additionally, much of the development effort is also applicable to traditional tube-and-wing aircraft, advanced aircraft configurations, and other structures where weight and through-the-thickness strength are design considerations.

PRSEUS Acoustic Panel Fabrication

NASA Technical Reports Server (NTRS)

Nicolette, Velicki; Yovanof, Nicolette P.; Baraja, Jaime; Mathur, Gopal; Thrash, Patrick; Pickell, Robert

2011-01-01

This report describes the development of a novel structural concept, Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body (BWB) airplane configuration with regards to acoustic response. A PRSEUS panel was designed and fabricated and provided to NASA-LaRC for acoustic response testing in the Structural Acoustics Loads and Transmission (SALT) facility). Preliminary assessments of the sound transmission characteristics of a PRSEUS panel subjected to a representative Hybrid Wing Body (HWB) operating environment were completed for the NASA Environmentally Responsible Aviation (ERA) Program.

Material Property Characterization of AS4/VRM-34 Textile Laminates

NASA Technical Reports Server (NTRS)

Grenoble, Ray W.; Johnston, William M

2013-01-01

Several material properties (modulus, strengths, and fracture toughness) of a textile composite have been evaluated to provide input data to analytical models of Pultruded Rod Stiffened Efficient Unitized Structure (PRSEUS). The material system is based on warp-knitted preforms of AS4 carbon fibers and VRM-34 epoxy resin, which have been processed via resin infusion and oven curing. Tensile, compressive, shear, and fracture toughness properties have been measured at ambient and elevated temperatures. All specimens were tested in as-fabricated (dry) condition. Specimens were tested with and without through-thickness stitching.

Pultruded Rod/Overwrap Testing for Various Stitched Stringer Configurations

NASA Technical Reports Server (NTRS)

Leone, Frank A., Jr.

2016-01-01

The unidirectional carbon pultruded rod running through the tops of the stringers is a key design feature of the Pultruded Rod Efficient Unitized Structure (PRSEUS) concept as applied to aircraft fuselage structure. Reported herein are the test methods and results from a test campaign in which the strength of the rod/overwrap interface of various PRSEUS stringer configurations were characterized. The different stringer configurations included different materials and stacking sequences for the stringer overwrap and whether or not an additional layer of adhesive was included between the rod and the overwrap.

Full-Scale Test and Analysis of a PRSEUS Fuselage Panel to Assess Damage-Containment Features

NASA Technical Reports Server (NTRS)

Bergan, Andrew; Bakuckas, John G.; Lovejoy, Andrew E.; Jegley, Dawn C.; Linton, Kim A.; Korkosz, Gregory; Awerbuch, Jonathan; Tan, Tein-Min

2011-01-01

Stitched composite technology has the potential to substantially decrease structural weight through enhanced damage containment capabilities. The most recent generation of stitched composite technology, the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept, has been shown to successfully arrest damage at the sub-component level through tension testing of a three stringer panel with damage in the form of a two-bay notch. In a joint effort undertaken by the National Aeronautics and Space Administration (NASA), the Federal Aviation Administration (FAA), and the Boeing Company, further studies are being conducted to characterize the damage containment features of the PRSEUS concept. A full-scale residual strength test will be performed on a fuselage panel to determine if the load capacity will meet strength, deformation, and damage tolerance requirements. A curved panel was designed, fabricated, and prepared for residual strength testing. A pre-test Finite Element Model (FEM) was developed using design allowables from previous test programs to predict test panel deformation characteristics and margins of safety. Three phases of testing with increasing damage severity include: (1) as manufactured; (2) barely visible impact damage (BVID) and visible impact damage (VID); and (3) discrete source damage (DSD) where the panel will be loaded to catastrophic failure. This paper presents the background information, test plan, and experimental procedure. This paper is the first of several future articles reporting the test preparations, results, and analysis conducted in the test program.

Evaluation of Acoustic Emission SHM of PRSEUS Composite Pressure Cube Tests

NASA Technical Reports Server (NTRS)

Horne, Michael R.; Madaras, Eric I.

2013-01-01

A series of tests of the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) pressure cube were conducted during third quarter 2011 at NASA Langley Research Center (LaRC) in the Combined Loads Test facility (COLTS). This is a report of the analysis of the Acoustic Emission (AE) data collected during those tests. The AE signals of the later tests are consistent with the final failure progression through two of the pressure cube panels. Calibration tests and damage precursor AE indications, from preliminary checkout pressurizations, indicated areas of concern that eventually failed. Hence those tests have potential for vehicle health monitoring.

The Behavior of a Stitched Composite Large-Scale Multi-Bay Pressure Box

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Rouse, Marshall; Przekop, Adam; Lovejoy, Andrew E.

2016-01-01

NASA has created the Environmentally Responsible Aviation (ERA) Project to develop technologies to reduce impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe to enable the introduction of unconventional aircraft configurations. NASA and The Boeing Company have worked together to develop a structural concept that is lightweight and an advancement beyond state-of-the-art composite structures. The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is an integrally stiffened panel design where elements are stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. With the PRSEUS concept, through-the-thickness stitches are applied through dry fabric prior to resin infusion, and replace fasteners throughout each integral panel. Through-the-thickness reinforcement at discontinuities, such as along flange edges, has been shown to suppress delamination and turn cracks, which expands the design space and leads to lighter designs. The pultruded rod provides stiffening away from the more vulnerable skin surface and improves bending stiffness. A series of building block tests were evaluated to explore the fundamental assumptions related to the capability and advantages of PRSEUS panels. The final step in the building block series of tests is an 80%-scale pressure box representing a portion of the center section of a Hybrid Wing Body (HWB) transport aircraft. The testing of this test article under maneuver and internal pressure loading conditions is the subject of this paper. The experimental evaluation of this article, along with the other building block tests and the accompanying analyses, has demonstrated the viability of a PRSEUS center body for the HWB vehicle. Additionally, much of the development effort is also applicable to traditional tube-and-wing aircraft, advanced aircraft configurations, and other structures where weight and through-the-thickness strength are design considerations.

Development of Stitched Composite Structure for Advanced Aircraft

NASA Technical Reports Server (NTRS)

Jegley, Dawn; Przekop, Adam; Rouse, Marshall; Lovejoy, Andrew; Velicki, Alex; Linton, Kim; Wu, Hsi-Yung; Baraja, Jaime; Thrash, Patrick; Hoffman, Krishna

2015-01-01

NASA has created the Environmentally Responsible Aviation Project to develop technologies which will reduce the impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe that will enable the introduction of unconventional aircraft configurations. NASA and The Boeing Company are working together to develop a structural concept that is lightweight and an advancement beyond state-of-the-art composites. The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is an integrally stiffened panel design where elements are stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. With the PRSEUS concept, through-the-thickness stitches are applied through dry fabric prior to resin infusion, and replace fasteners throughout each integral panel. Through-the-thickness reinforcement at discontinuities, such as along flange edges, has been shown to suppress delamination and turn cracks, which expands the design space and leads to lighter designs. The pultruded rod provides stiffening away from the more vulnerable skin surface and improves bending stiffness. A series of building blocks were evaluated to explore the fundamental assumptions related to the capability and advantages of PRSEUS panels. These building blocks addressed tension, compression, and pressure loading conditions. The emphasis of the development work has been to assess the loading capability, damage arrestment features, repairability, post-buckling behavior, and response of PRSEUS flat panels to out-of plane pressure loading. The results of this building-block program from coupons through an 80%-scale pressure box have demonstrated the viability of a PRSEUS center body for the Hybrid Wing Body (HWB) transport aircraft. This development program shows that the PRSEUS benefits are also applicable to traditional tube-andwing aircraft, those of advanced configurations, and other structures where weight and through-the-thickness strength are design considerations. An overview of the development of PRSEUS technology for commercial transport aircraft is the subject of this paper.

Automation of a suturing device for minimally invasive surgery.

PubMed

Göpel, Tobias; Härtl, Felix; Schneider, Armin; Buss, Martin; Feussner, Hubertus

2011-07-01

In minimally invasive surgery, hand suturing is categorized as a challenge in technique as well as in its duration. This calls for an easily manageable tool, permitting an all-purpose, cost-efficient, and secure viscerosynthesis. Such a tool for this field already exists: the Autosuture EndoStitch(®). In a series of studies the potential for the EndoStitch to accelerate suturing has been proven. However, its ergonomics still limits its applicability. The goal of this study was twofold: propose an optimized and partially automated EndoStitch and compare the conventional EndoStitch to the optimized and partially automated EndoStitch with respect to the speed and precision of suturing. Based on the EndoStitch, a partially automated suturing tool has been developed. With the aid of a DC motor, triggered by a button, one can suture by one-fingered handling. Using the partially automated suturing manipulator, 20 surgeons with different levels of laparoscopic experience successfully completed a continuous suture with 10 stitches using the conventional and the partially automated suture manipulator. Before that, each participant was given 1 min of instruction and 1 min for training. Absolute suturing time and stitch accuracy were measured. The quality of the automated EndoStitch with respect to manipulation was tested with the aid of a standardized questionnaire. To compare the two instruments, t tests were used for suturing accuracy and time. Of the 20 surgeons with laparoscopic experience (fewer than 5 laparoscopic interventions, n=9; fewer than 20 laparoscopic interventions, n=7; more than 20 laparoscopic interventions, n=4), there was no significant difference between the two tested systems with respect to stitching accuracy. However, the suturing time was significantly shorter with the Autostitch (P=0.01). The difference in accuracy and speed was not statistically significant considering the laparoscopic experience of the surgeons. The weight and size of the Autostitch have been criticized as well as its cable. However, the comfortable handhold, automatic needle change, and ergonomic manipulation have been rated positive. Partially automated suturing in minimally invasive surgery offers advantages with respect to the speed of operation and ergonomics. Ongoing work in this field has to concentrate on minimization, implementation in robotic systems, and development of new operation methods (NOTES).

Etude comparative sur la propagation de l'endommagement apres impact des composites carbone/epoxy renforces par piquage au fil Kevlar et titane-nickel

NASA Astrophysics Data System (ADS)

Vachon, Pierre-Luc

Composite laminates have strong in-plane mechanical properties, but they are generally weaker through their thickness. This specificity makes the laminates prone to delamination, particularly under low-velocity impact loads. Consequently numerous research efforts have been dedicated to developing interlaminar reinforcing methods, such as transverse stitching. The present project proposes the use of the stitching technique combined with a special stitching thread made of superelastic TiNi alloy. This technology is intended to improve the delamination toughness in composite laminates loaded in bending. In the first part of this study a numerical model was developed for analyzing composite structures. The 3-D finite element model was built with the ANSYS commercial software using 20-node solid and 8-node shell elements. The progressive damage modeling technique was used, allowing the prediction of delamination propagation in a laminate submitted to various loading modes. The model was validated for a plate under quasi-static traction load, and it was then used to simulate three-point bending tests. Secondly, carbon/epoxy composite panels were fabricated, with each panel containing unstitched and stitched specimens. Two different materials were used for the stitching thread: superelastic TiNi wires and Kevlar threads as a reference. Some stitched specimens were cut in slices in order to make some observations of the internal stitch using an optical microscope. Standardized low-velocity impact tests and compression after impact tests were carried out on stitched and unstitched specimens (ASTM D7136 and D7137). The Kevlar reinforcements have shown great performance in reducing the delaminated zone after impact, as well as in improving the residual compression strength. The TiNi reinforcements provided encouraging results during the impact tests, though being less effective than the Kevlar threads. During the compression after impact tests, only a slight difference could be measured between the TiNi-stitched and the unstitched specimens. Then the bending performance of the specimens was quantified experimentally by calculating the energy required to create a unit volume of damaged material (Gv, J/mm3). This metric is similar to the Strain Energy Release Rate (SERR) commonly used in studies on delamination. According to the experimental results, the damage resistance in three-point bending was not improved by the Kevlar reinforcements, despite the reduced damaged zone after the impact test. Indeed, when the strain energy in bending is relativized to the induced damaged volume during propagation, it turns out that the TiNi reinforcements are more effective than the Kevlar's for improving the damage resistance. Finally, the numerical study on the behavior of both types of stitched reinforcements allowed identifying subtle differences between those. Indeed, both stitching threads (TiNi and Kevlar) promoted the interlaminar propagation of the delamination during simulation of the bending test, with this behavior being less pronounced for the TiNi-stitched plate. However the Kevlar threads seemed more effective for stopping this propagation in the zones between the stitches. Keywords: composite materials, stitching, numerical model, shape memory alloy, three-point bending, low-velocity impact, ultrasound imaging.

Automated apparatus and method of generating native code for a stitching machine

NASA Technical Reports Server (NTRS)

Miller, Jeffrey L. (Inventor)

2000-01-01

A computer system automatically generates CNC code for a stitching machine. The computer determines the locations of a present stitching point and a next stitching point. If a constraint is not found between the present stitching point and the next stitching point, the computer generates code for making a stitch at the next stitching point. If a constraint is found, the computer generates code for changing a condition (e.g., direction) of the stitching machine's stitching head.

Preliminary Weight Savings Estimate for a Commercial Transport Wing Using Rod-Stiffened Stitched Composite Technology

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.

2015-01-01

A structural concept called pultruded rod stitched efficient unitized structure (PRSEUS) was developed by the Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body (HWB) aircraft configuration. While PRSEUS was an enabling technology for the pressurized HWB structure, limited investigation of PRSEUS for other aircraft structures, such as circular fuselages and wings, has been done. Therefore, a study was undertaken to investigate the potential weight savings afforded by using the PRSEUS concept for a commercial transport wing. The study applied PRSEUS to the Advanced Subsonic Technology (AST) Program composite semi-span test article, which was sized using three load cases. The initial PRSEUS design was developed by matching cross-sectional stiffnesses for each stringer/skin combination within the wing covers, then the design was modified to ensure that the PRSEUS design satisfied the design criteria. It was found that the PRSEUS wing design exhibited weight savings over the blade-stiffened composite AST Program wing of nearly 9%, and a weight savings of 49% and 29% for the lower and upper covers, respectively, compared to an equivalent metallic wing.

Automated quality control for stitching of textile articles

NASA Technical Reports Server (NTRS)

Miller, Jeffrey L. (Inventor); Markus, Alan (Inventor)

1999-01-01

Quality control for stitching of a textile article is performed by measuring thread tension in the stitches as the stitches are being made, determining locations of the stitches, and generating a map including the locations and stitching data derived from the measured thread tensions. The stitching data can be analyzed, off-line or in real time, to identify defective stitches. Defective stitches can then be repaired. Real time analysis of the thread tensions allows problems such as broken needle threads to be corrected immediately.

Advanced stitching head for making stitches in a textile article having variable thickness

NASA Technical Reports Server (NTRS)

Thrash, Patrick J. (Inventor); Miller, Jeffrey L. (Inventor); Codos, Richard (Inventor)

1999-01-01

A stitching head for a computer numerically controlled stitching machine includes a thread tensioning mechanism for automatically adjusting thread tension according to the thickness of the material being stitched. The stitching head also includes a mechanism for automatically adjusting thread path geometry according to the thickness of the material being stitched.

Comparison of resin film infusion, resin transfer molding, and consolidation of textile preforms for primary aircraft structure

NASA Technical Reports Server (NTRS)

Suarez, J.; Dastin, S.

1992-01-01

Innovative design concepts and cost effective fabrication processes were developed for damage tolerant primary structures that can perform at a design ultimate strain level of 6000 micro inch/inch. Attention focused on the use of textile high performance fiber reinforcement concepts that provide improved damage tolerance and out-of-plane load capability, low cost resin film infusion (RFI) and resin transfer molding (RTM) processes, and thermoplastic forming concepts. The fabrication of wing 'Y' spars by four different materials and/or processes methods is described: fabricated using IM7 angle interlock 0 to 90 deg woven preforms with + or - 45 deg plies stitched with Toray high strength graphite thread and processed using RFI and 3501-6 epoxy; fabricated using G40-800 knitted/stitched preforms and processed using RFI and 3501-6 epoxy; fabricated using G40-800 knitted/stitched preforms using RTM and Tactix 123/H41 epoxy; and fabricated preforms using AS4(6K)/PEEK 150 g commingled angle interlock 0 to 90 deg woven preforms with + or - 45 deg commingled plies stitched using high strength graphite thread and processed by consolidation. Structural efficiency, processability, and acquisition cost are compared.

Experimental Study of the Mode I Interlaminar Fracture Toughness Improvement on Stitched CFRP Laminates

NASA Astrophysics Data System (ADS)

Iwahori, Yutaka; Ishikawa, Takashi; Watanabe, Naoyuki; Hayashi, Yoichi; Ito, Akira

Experimental investigations have been made on the mode I interlaminar fracture toughness (GIC) of stitched CFRP (carbon fiber reinforced plastic) laminates. The GIC of stitched CFRP laminates fabricated by resin transfer molding (RTM) and stitching with five kinds of stitch thread thicknesses, 400d (denier), 600d, 800d, 1000d, and 1200d were experimentally obtained by double cantilever beam (DCB) tests. Interlaminar tension tests for stitched CFRP laminates for a specimen containing only one stitch thread were also carried out. The consumption energy of the single stitched CFRP laminates (Wt) and stitch threads broken modes were obtained by such interlaminar tension tests. DCB test results show that the GIC of stitched CFRP laminates of several stitch thread thicknesses are governed by stitch density (SD). It is found that the relationship between ΔGIC/ΔSD and Wt are linear function. In other words, the GIC of Kevlar® stitched CFRP laminates is not only governed by SD but also Wt obtained from the interlaminar tension tests. It is also suggested that the interlaminar tension test results exhibit the potential for GIC estimation on the Kevlar® stitched CFRP laminates instead of conducting the DCB tests.

Automated gantry-type stitching system

NASA Technical Reports Server (NTRS)

Thrash, Patrick J. (Inventor); Miller, Jeffrey L. (Inventor); Pallas, Kenneth G. (Inventor); Trank, Robert C. (Inventor); Fox, Rhoda (Inventor); Korte, Mike (Inventor); Codos, Richard (Inventor); Korolev, Aleksandr (Inventor); Collan, William (Inventor)

1999-01-01

A stitching system includes a gantry that is movable along a material support table. Mounted to the gantry are a plurality of stitching heads and bobbins. The stitching heads are individually controllable in a z-direction, and the bobbins are individually controllable in the z-direction. Each stitching head is paired with a bobbin. Each pair of stitching heads and the bobbins is controlled synchronously in the z-direction. The stitching system is well-suited for stitching preforms of aircraft wing covers and other preforms having variable thickness and compound, contoured three-dimensional surfaces.

KSC-04pd0618

NASA Image and Video Library

2004-03-24

KENNEDY SPACE CENTER, FLA. -- In the Thermal Protection System Facility, Pilar Ryan, with United Space Alliance, stitches a piece of insulation blanket for Atlantis's nose cap. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

Experimental investigation of effects of stitching orientation on forming behaviors of 2D P-aramid multilayer woven preform

NASA Astrophysics Data System (ADS)

Abtew, Mulat Alubel; Boussu, François; Bruniaux, Pascal; Loghin, Carmen; Cristian, Irina; Chen, Yan; Wang, Lichuan

2018-05-01

In many textile applications stitching process is one of the widely used methods to join the multi-layer fabric plies not only due to its easy applicability and flexible production but also provide structural integrity throughout-the-thickness of materials. In this research, the influences of stitching pattern on various molding characteristics of multi-layer 2D para-aramid plain woven fabrics while deformation was investigated. The fabrics were made of high performance fiber with 930dtex yarn linear density and fabric areal density of 200gm/m2. First, different stitch pattern (orientation) was applied for joining the mentioned multi-layered fabrics keeping other stitching parameters such as stitch gap, stitch thread tension, stitch length, stitch type, stitch thread type etc. constant throughout the study. Then, a pneumatic based molding device with a low speed forming process specially designed for preforming of textile with a predefined hemispherical shape of punch. The result shows that stitching pattern is one of the parameter that influences the different molding behavior and should be consider while molding stitched multi-layer fabrics.

A Unified Framework for Street-View Panorama Stitching

PubMed Central

Li, Li; Yao, Jian; Xie, Renping; Xia, Menghan; Zhang, Wei

2016-01-01

In this paper, we propose a unified framework to generate a pleasant and high-quality street-view panorama by stitching multiple panoramic images captured from the cameras mounted on the mobile platform. Our proposed framework is comprised of four major steps: image warping, color correction, optimal seam line detection and image blending. Since the input images are captured without a precisely common projection center from the scenes with the depth differences with respect to the cameras to different extents, such images cannot be precisely aligned in geometry. Therefore, an efficient image warping method based on the dense optical flow field is proposed to greatly suppress the influence of large geometric misalignment at first. Then, to lessen the influence of photometric inconsistencies caused by the illumination variations and different exposure settings, we propose an efficient color correction algorithm via matching extreme points of histograms to greatly decrease color differences between warped images. After that, the optimal seam lines between adjacent input images are detected via the graph cut energy minimization framework. At last, the Laplacian pyramid blending algorithm is applied to further eliminate the stitching artifacts along the optimal seam lines. Experimental results on a large set of challenging street-view panoramic images captured form the real world illustrate that the proposed system is capable of creating high-quality panoramas. PMID:28025481

The European Academy laparoscopic “Suturing Training and Testing’’ (SUTT) significantly improves surgeons’ performance

PubMed Central

Sleiman, Z.; Tanos, V.; Van Belle, Y.; Carvalho, J.L.; Campo, R.

2015-01-01

The efficiency of suturing training and testing (SUTT) model by laparoscopy was evaluated, measuring the suturingskill acquisition of trainee gynecologists at the beginning and at the end of a teaching course. During a workshop organized by the European Academy of Gynecological Surgery (EAGS), 25 participants with three different experience levels in laparoscopy (minor, intermediate and major) performed the 4 exercises of the SUTT model (Ex 1: both hands stitching and continuous suturing, Ex 2: right hand stitching and intracorporeal knotting, Ex 3: left hand stitching and intracorporeal knotting, Ex 4: dominant hand stitching, tissue approximation and intracorporeal knotting). The time needed to perform the exercises is recorded for each trainee and group and statistical analysis used to note the differences. Overall, all trainees achieved significant improvement in suturing time (p < 0.005) as measured before and after completion of the training. Similar significantly improved suturing time differences (p < 0.005) were noted among the groups of trainees with different laparoscopic experience. In conclusion a short well-guided training course, using the SUTT model, improves significantly surgeon’s laparoscopic suturing ability, independently of the level of experience in laparoscopic surgery. Key words: Endoscopy, laparoscopic suturing, psychomotor skills, surgery, teaching, training suturing model. PMID:26977264

Design and Analysis of a Stiffened Composite Structure Repair Concept

NASA Technical Reports Server (NTRS)

Przekop, Adam

2011-01-01

A design and analysis of a repair concept applicable to a stiffened thin-skin composite panel based on the Pultruded Rod Stitched Efficient Unitized Structure is presented. Since the repair concept is a bolted repair using metal components, it can easily be applied in the operational environment. Initial analyses are aimed at validating the finite element modeling approach by comparing with available test data. Once confidence in the analysis approach is established several repair configurations are explored and the most efficient one presented. Repairs involving damage to the top of the stiffener alone are considered in addition to repairs involving a damaged stiffener, flange and underlying skin. High fidelity finite element modeling techniques such as mesh-independent definition of compliant fasteners, elastic-plastic metallic material properties and geometrically nonlinear analysis are utilized in the effort. The results of the analysis are presented and factors influencing the design are assessed and discussed.

Open hole and postimpact compressive fatigue of stitched and unstitched carbon-epoxy composites

NASA Technical Reports Server (NTRS)

Portanova, Marc A.; Poe, Clarence C.; Whitcomb, John D.

1992-01-01

The performance is studied of a stitched uniweave fabric composite and that of a toughened tape composite. The effects of stitching on compression fatigue life are addressed. Post impact compression fatigue and open hole fatigue tests were run on an AS4/3501-6 uniweave with stitching and a toughened IM7/8551-7 tape without stitching. Stitching was found to increase the thickness and consequently the weight of the composite material. The two materials were compared on an equal carbon content basis as well as on an equal weight basis. The excess thickness in the stitched uniweave composite was responsible for the lower fatigue life, on an equal carbon basis, compared to the toughened resin tape composite. Comparison of fatigue lives on an equal carbon content basis indicated that puncture or crimp type damage from stitching has very little effect on compression failure. Post impact fatigue test showed that although the damage area in the stitched uniweave composite was twice that of the toughened tape composite, the fatigue lives of the stitched composite were significantly longer than those of the toughened composite. Thus, it appears that the increase in thickness from stitching is much more of a penalty than crimped fibers or puncture type damage from stitching.

Open hole and post-impact compression fatigue of stitched and unstitched carbon/epoxy composites

NASA Technical Reports Server (NTRS)

Portanova, M. A.; Poe, C. C., Jr.; Whitcomb, John D.

1990-01-01

The performance is studied of a stitched uniweave fabric composite and that of a toughened tape composite. The effects of stitching on compression fatigue life are addressed. Post impact compression fatigue and open hole fatigue tests were run on an AS4/3501-6 uniweave with stitching and a toughened IM7/8551-7 tape without stitching. Stitching was found to increase the thickness and consequently the weight of the composite material. The two materials were compared on an equal carbon content basis as well as on an equal weight basis. The excess thickness in the stitched uniweave composite was responsible for the lower fatigue life, on an equal carbon basis, compared to the toughened resin tape composite. Comparison of fatigue lives on an equal carbon content basis indicated that puncture or crimp type damage from stitching has very little effect on compression failure. Post impact fatigue test showed that although the damage area in the stitched uniweave composite was twice that of the toughened tape composite, the fatigue lives of the stitched composite were significantly longer than those of the toughened composite. Thus, it appears that the increase in thickness from stitching is much more of a penalty than crimped fibers or puncture type damage from stitching.

A designed experiment in stitched/RTM composites

NASA Technical Reports Server (NTRS)

Dickinson, Larry C.

1993-01-01

The damage tolerance of composite laminates can be significantly improved by the addition of through-the-thickness fibrous reinforcement such as stitching. However, there are numerous stitching parameters which can be independently varied, and their separate and combined effects on mechanical properties need to be determined. A statistically designed experiment (a 2(sup 5-1) fractional factorial, also known as a Taguchi L16 test matrix) used to evaluate five important parameters is described. The effects and interactions of stitch thread material, stitch thread strength, stitch row spacing and stitch pitch are examined for both thick (48 ply) and thin (16 ply) carbon/epoxy (AS4/E905L) composites. Tension, compression and compression after impact tests are described. Preliminary results of completed tension testing are discussed. Larger threads decreased tensile strength. Panel thickness was found not to be an important stitching parameter for tensile properties. Tensile modulus was unaffected by stitching.

KSC-04pd0614

NASA Image and Video Library

2004-03-24

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Michael Williams and Ginger Morrison stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

KSC-04pd0613

NASA Image and Video Library

2004-03-24

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Ginger Morrison and Michael Williams stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches.

KSC-04PD-0613

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Ginger Morrison and Michael Williams stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches.

KSC-04PD-0616

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Ginger Morrison and Michael Williams stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through- stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

KSC-04pd0616

NASA Image and Video Library

2004-03-24

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Ginger Morrison and Michael Williams stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

KSC-04PD-0614

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Michael Williams and Ginger Morrison stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through- stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

Impact resistance and interlaminar fracture toughness of through-the-thickness reinforced graphite/epoxy

NASA Technical Reports Server (NTRS)

Dexter, H. B.; Funk, J. G.

1986-01-01

Five through-the-thickness stitch configurations are analyzed to determine the effect of impact resistance and interlaminar fracture toughness on T3000/3501-6 graphite/epoxy. The test specimens were stitched with either polyester or Kevlar yarns and with various stitch parameters. Tension and compression mechanical, impact and compression-after-impact, and double cantilever beam tests were conducted. It is observed that the stitched laminates have tension and compression strengths 20-25 percent lower than the strengths of unstitched laminates, the tension strength of stitched laminates is reduced with increasing number of stitches, and the compression strength increases as the number of stitches are increased. The impact data reveal that the Kevlar stitched laminates have less damage than unstitched laminates; the most effective configuration for suppressing impact damage and improving interlaminar fracture toughness consists of Kevlar yarns 1/4 inch apart with eight stitches per inch. The mode 1 critical strain energy release rate for the 1/4 inch Kevlar eight stitch laminate was calculated as 30 times higher than that of the unstitched.

Triple-loaded single-anchor stitch configurations: an analysis of cyclically loaded suture-tendon interface security.

PubMed

Coons, David A; Barber, F Alan; Herbert, Morley A

2006-11-01

This study evaluated the strength and suture-tendon interface security of different suture configurations from triple-suture-loaded anchors. A juvenile bovine infraspinatus tendon was detached and repaired by use of 4 different suture combinations from 2 suture anchors: 3 simple sutures in each anchor (ThreeVo anchor; Linvatec, Largo, FL); 2 peripheral simple stitches and 1 central horizontal mattress suture passed deeper into the tendon, creating a larger footprint (bigfoot-print anchor); 2 peripheral simple stitches with 1 central horizontal mattress stitch passed through the same holes as the simple sutures (stitch-of-Burns); and 2 simple stitches (TwoVo anchor; Linvatec). The constructs were cyclically loaded between 10 N and 180 N for 3,500 cycles and then destructively tested. The number of cycles required to create a 5-mm gap and a 10-mm gap and the ultimate load to failure and failure mode were recorded. The ThreeVo anchor was strongest and most resistant to cyclic loading (P < .01). The TwoVo anchor was least resistant to cyclic loading. The stitch-of-Burns anchor was more resistant to cyclic loading than both the bigfoot-print anchor and the TwoVo anchor (P < .03). The ThreeVo, stitch-of-Burns, and TwoVo anchors were stronger than the bigfoot-print anchor (P < .05). Three simple sutures in an anchor hold better than two simple sutures. Three simple sutures provide superior suture-tendon security than combinations of one mattress and two simple stitches subjected to cyclic loading. A central mattress stitch placed more medially than two peripheral simple stitches (bigfoot-print anchor) configured to enlarge the tendon-suture footprint was not as resistant to cyclic loading or destructive testing as three simple stitches (ThreeVo anchor). Placing a central mattress stitch more medially than 2 peripheral simple stitches to enlarge the tendon-suture footprint was not as resistant to cyclic loading or destructive testing as 3 simple stitches.

Effects of stitching on fracture toughness of uniweave textile graphite/epoxy laminates

NASA Technical Reports Server (NTRS)

Sankar, Bhavani V.; Sharma, Suresh

1995-01-01

The effects of through-the-thickness stitching on impact damage resistance, impact damage tolerance, and Mode 1 and Mode 2 fracture toughness of textile graphite/epoxy laminates were studied experimentally. Graphite/epoxy laminates were fabricated from AS4 graphite uniweave textiles and 3501-6 epoxy using Resin Transfer Molding. The cloths were stitched with Kevlar(tm) and glass yarns before resin infusion. Delamination was implanted during processing to simulate impact damage. Sublaminate buckling tests were performed in a novel fixture to measure Compression After Impact (CAI) strength of stitched laminates. The results show that CAI strength can be improved up to 400% by through-the-thickness stitching. Double Cantilever Beam tests were performed to study the effect of stitching on Mode 1 fracture toughness G(sub 1c). It was found that G(sub 1c) increased 30 times for a low stitching density of 16 stitches/sq in. Mode 2 fracture toughness was measured by testing the stitched beams in End Notch Flexure tests. Unlike in the unstitiched beams, crack propagation in the stitched beams was steady. The current formulas for ENF tests were not found suitable for determining G(sub 2C) for stitched beams. Hence two new methods were developed - one based on crack area measured from ultrasonic C-scanning and the other based on equivalent crack area measured from the residual stiffness of the specimen. The G(sub 2c) was found to be at least 5-15 times higher for the stitched laminates. The mechanisms by which stitching increases the CAI strength and fracture toughness are discussed.

Damage Arresting Composites for Shaped Vehicles

NASA Technical Reports Server (NTRS)

Velicki, Alex

2009-01-01

This report describes the development of a novel structural solution that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body configurations that are described in NASA NRA subtopic A2A.3, "Materials and Structures for Wing Components and Non-Circular Fuselage." The phase I portion of this task includes a comprehensive finite element model-based structural sizing exercise performed using the BWB airplane configuration to generate internal loads and fuselage panel weights for an advanced Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) structural concept. An accompanying element-level test program is also described which substantiates the analytical results and calculation methods used in the trade study. The phase II plan for the continuation of this research is also included herein.

On the inter-stitch interaction in biaxial non-crimp fabrics

NASA Astrophysics Data System (ADS)

Colin, David; Bel, Sylvain; Hans, Thorsten; Hartmann, Mathias

2018-05-01

Simulation models of fiber reinforcements at the scale of fibers possibly reproduce important deformation mechanisms and can offer predictive capabilities on the macroscopic mechanical behavior. Although potential deformation mechanisms are already listed in the literature, these phenomena should be experimentally investigated to evaluate their relevance in simulation at the scale of fibers. This study focuses on the inter-stitch interaction of Non-Crimp Fabric (NCF) and aims at quantifying the relative motion of the stitching yarns. To this end, controlled shear deformation was introduced on +/-45° biaxial tricot stitched NCF. The stitching yarns have been colored on the backside of the sample while the front face remained uncolored. Therefore, an inter-stitch relative motion can be observed if an uncolored portion of the stitching yarn appears on the back face of the sample. The samples were observed during the experiments with a digital microscope in order to measure the uncolored portion of the yarns on the back face. Thus, the stitching yarn movement can be quantified for various shear angles. A significant relative motion was observed compared to the original stitching length. Based on this study, the authors argue that the inter-stitch sliding is a relevant deformation mechanism for biaxial tricot stitched NCF at the scale of fibers.

Alternative stitching method for massively parallel e-beam lithography

NASA Astrophysics Data System (ADS)

Brandt, Pieter; Tranquillin, Céline; Wieland, Marco; Bayle, Sébastien; Milléquant, Matthieu; Renault, Guillaume

2015-03-01

In this study a novel stitching method other than Soft Edge (SE) and Smart Boundary (SB) is introduced and benchmarked against SE. The method is based on locally enhanced Exposure Latitude without cost of throughput, making use of the fact that the two beams that pass through the stitching region can deposit up to 2x the nominal dose. The method requires a complex Proximity Effect Correction that takes a preset stitching dose profile into account. On a Metal clip at minimum half-pitch of 32 nm for MAPPER FLX 1200 tool specifications, the novel stitching method effectively mitigates Beam to Beam (B2B) position errors such that they do not induce increase in CD Uniformity (CDU). In other words, the same CDU can be realized inside the stitching region as outside the stitching region. For the SE method, the CDU inside is 0.3 nm higher than outside the stitching region. 5 nm direct overlay impact from B2B position errors cannot be reduced by a stitching strategy.

Alternative stitching method for massively parallel e-beam lithography

NASA Astrophysics Data System (ADS)

Brandt, Pieter; Tranquillin, Céline; Wieland, Marco; Bayle, Sébastien; Milléquant, Matthieu; Renault, Guillaume

2015-07-01

In this study, a stitching method other than soft edge (SE) and smart boundary (SB) is introduced and benchmarked against SE. The method is based on locally enhanced exposure latitude without throughput cost, making use of the fact that the two beams that pass through the stitching region can deposit up to 2× the nominal dose. The method requires a complex proximity effect correction that takes a preset stitching dose profile into account. Although the principle of the presented stitching method can be multibeam (lithography) systems in general, in this study, the MAPPER FLX 1200 tool is specifically considered. For the latter tool at a metal clip at minimum half-pitch of 32 nm, the stitching method effectively mitigates beam-to-beam (B2B) position errors such that they do not induce an increase in critical dimension uniformity (CDU). In other words, the same CDU can be realized inside the stitching region as outside the stitching region. For the SE method, the CDU inside is 0.3 nm higher than outside the stitching region. A 5-nm direct overlay impact from the B2B position errors cannot be reduced by a stitching strategy.

Comparison of resin film infusion, resin transfer molding, and consolidation of textile preforms for primary aircraft structure

NASA Technical Reports Server (NTRS)

Suarez, J.; Dastin, S.

1992-01-01

Under NASA's Novel Composites for Wing and Fuselage Applications (NCWFA) Program, Grumman is developing innovative design concepts and cost-effective fabrication processes for damage-tolerant primary structures that can perform at a design ultimate strain level of 6000 micro-inch/inch. Attention has focused on the use of textile high-performance fiber-reinforcement concepts that provide improved damage tolerance and out-of-plane load capability, low-cost resin film infusion (RFI) and resin transfer molding (RTM) processes, and thermoplastic forming concepts. The fabrication of wing 'Y' spars by four different materials/processes methods is described: 'Y' spars fabricated using IM7 angle interlock 0/90 deg woven preforms with +/- 45 deg plies stitched with Toray high-strength graphite thread and processed using RFI and 3501-6 epoxy; 'Y' spars fabricated using G40-800 knitted/stitched preforms and processed using RFI and 3501-6 epoxy; 'Y' spars fabricated using G40-800 knitted/stitched preforms and processed using RTM and Tactix 123/H41 epoxy; and 'Y' spars fabricated using AS4(6k)/PEEK 150-g commingled angle interlock 0/90 deg woven preforms with +/- 45 deg commingled plies stitched using high-strength graphite thread and processed by consolidation. A comparison of the structural efficiency, processability, and projected acquisition cost of these representative spars is presented.

The Use of the STAGS Finite Element Code in Stitched Structures Development

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Lovejoy, Andrew E.

2014-01-01

In the last 30 years NASA has worked in collaboration with industry to develop enabling technologies needed to make aircraft more fuel-efficient and more affordable. The focus on the airframe has been to reduce weight, improve damage tolerance and better understand structural behavior under realistic flight and ground loading conditions. Stitched structure is a technology that can address the weight savings, cost reduction, and damage tolerance goals, but only if it is supported by accurate analytical techniques. Development of stitched technology began in the 1990's as a partnership between NASA and Boeing (McDonnell Douglas at the time) under the Advanced Composites Technology Program and has continued under various titles and programs and into the Environmentally Responsible Aviation Project today. These programs contained development efforts involving manufacturing development, design, detailed analysis, and testing. Each phase of development, from coupons to large aircraft components was supported by detailed analysis to prove that the behavior of these structures was well-understood and predictable. The Structural Analysis of General Shells (STAGS) computer code was a critical tool used in the development of many stitched structures. As a key developer of STAGS, Charles Rankin's contribution to the programs was quite significant. Key features of STAGS used in these analyses and discussed in this paper include its accurate nonlinear and post-buckling capabilities, its ability to predict damage growth, and the use of Lagrange constraints and follower forces.

Table-driven software architecture for a stitching system

NASA Technical Reports Server (NTRS)

Thrash, Patrick J. (Inventor); Miller, Jeffrey L. (Inventor); Pallas, Ken (Inventor); Trank, Robert C. (Inventor); Fox, Rhoda (Inventor); Korte, Mike (Inventor); Codos, Richard (Inventor); Korolev, Alexandre (Inventor); Collan, William (Inventor)

2001-01-01

Native code for a CNC stitching machine is generated by generating a geometry model of a preform; generating tool paths from the geometry model, the tool paths including stitching instructions for making stitches; and generating additional instructions indicating thickness values. The thickness values are obtained from a lookup table. When the stitching machine runs the native code, it accesses a lookup table to determine a thread tension value corresponding to the thickness value. The stitching machine accesses another lookup table to determine a thread path geometry value corresponding to the thickness value.

One-dimensional angular-measurement-based stitching interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Lei; Xue, Junpeng; Gao, Bo

In this paper, we present one-dimensional stitching interferometry based on the angular measurement for high-precision mirror metrology. The tilt error introduced by the stage motion during the stitching process is measured by an extra angular measurement device. The local profile measured by the interferometer in a single field of view is corrected using the measured angle before the piston adjustment in the stitching process. Comparing to the classical software stitching technique, the angle measuring stitching technique is more reliable and accurate in profiling mirror surface at the nanometer level. Experimental results demonstrate the feasibility of the proposed stitching technique. Basedmore » on our measurements, the typical repeatability within 200 mm scanning range is 0.5 nm RMS or less.« less

One-dimensional angular-measurement-based stitching interferometry

DOE PAGES

Huang, Lei; Xue, Junpeng; Gao, Bo; ...

2018-04-05

In this paper, we present one-dimensional stitching interferometry based on the angular measurement for high-precision mirror metrology. The tilt error introduced by the stage motion during the stitching process is measured by an extra angular measurement device. The local profile measured by the interferometer in a single field of view is corrected using the measured angle before the piston adjustment in the stitching process. Comparing to the classical software stitching technique, the angle measuring stitching technique is more reliable and accurate in profiling mirror surface at the nanometer level. Experimental results demonstrate the feasibility of the proposed stitching technique. Basedmore » on our measurements, the typical repeatability within 200 mm scanning range is 0.5 nm RMS or less.« less

KSC-04pd0621

NASA Image and Video Library

2004-03-24

KENNEDY SPACE CENTER, FLA. -- In the Thermal Protection System Facility, Pilar Ryan, with United Space Alliance, stitches a piece of insulation blanket for Atlantis' nose cap. Behind her is a cover for the nose cap. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

Parametric studies of stitching effectiveness for preventing substructure disbond

NASA Technical Reports Server (NTRS)

Flanagan, Gerry; Furrow, Keith

1995-01-01

A methodology is desired that will allow a designer to select appropriate amounts of through-thickness reinforcement needed to meet design requirements. The goal is to use a relatively simple analysis to minimize the amount of testing that needs to be performed, and to make test results from simple configurations applicable to more general structures. Using this methodology one should be able to optimize the selection of stitching materials, the weight of the yarn, and the stitching density. The analysis approach is to treat substructure disbond as a crack propagation problem. In this approach, the stitches have little influence until a delamination begins to grow. Once the delamination reaches, or extends beyond a stitch, the stitch serves to reduce the strain-energy-release-rate (G) at the crack tip for a given applied load. The reduced G can then be compared to the unstitched materials toughness to predict the load required to further extend the crack. The current model treats the stitch as a simple spring which responds to displacements in the vertical (through-thickness) direction. In concept, this approach is similar to that proposed by other authors. Test results indicate that the model should be refined to include the shearing stiffness of the stitch. The strain-energy-release-rate calculations are performed using a code which uses interconnected higher-order plates to model built-up composite cross-sections. When plates are stacked vertically, the interfacial tractions between the plates can be computed. The plate differential equations are solved in closed-form. The code, called SUBLAM, was developed as part of this section in one dimension. Because of this limitation, rows of stitches are treated as a two-dimensional sheet. The spring stiffness of a row of stitches can be estimated from the stitch material, weight, and density. As a practical and conservative approach, we can assume that the stitch is bonded until a crack passes the stitch location. After the crack passes, it is fully bonded. A series of tests were performed to exercise this methodology and incorporated an attached flange such that the sudden change in thickness initiated a delamination. The analysis was used to estimate the materials' critical G from that of the unstitched specimens. With this data, a prediction was made for the load required to delaminate the stitched specimens. Using the methodology, design charts have been created for simplified geometries. These charts give stitch force, along with G(sub 1) and G(sub 2) as as function of the stitch spring stiffness. Using the charts, it should be possible to determine the stitch spring stiffness and strength required to reduce the G to a desired level. From these parameters, the actual stitching material, weight, and density can be computed.

Imparting Barely Visible Impact Damage to a Stitched Composite Large-Scale Pressure Box

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.; Przekop, Adam

2016-01-01

The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is a concept that was developed by The Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body (HWB) aircraft configuration, which has been a focus of the NASA Environmentally Responsible Aviation Project. The NASA-Boeing structural development for the HWB aircraft culminated in testing of the multi-bay box, which is an 80%-scale representation of the pressurized center-body section. This structure was tested in the NASA Langley Research Center Combined Loads Test System facility. As part of this testing, barely visible impact damage was imparted to the interior and exterior of the test article to demonstrate compliance with a condition representative of the requirements for Category 1 damaged composite structure as defined by the Federal Aviation Regulations. Interior impacts were imparted using an existing spring-loaded impactor, while the exterior impacts were imparted using a newly designed, gravity-driven impactor. This paper describes the impacts to the test article, and the design of the gravitydriven guided-weight impactor. The guided-weight impactor proved to be a very reliable method to impart barely visible impact damage in locations which are not easily accessible for a traditional drop-weight impactor, while at the same time having the capability to be highly configurable for use on other aircraft structures.

Development of the PRSEUS Multi-Bay Pressure Box for a Hybrid Wing Body Vehicle

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Velicki, Alexander

2015-01-01

NASA has created the Environmentally Responsible Aviation Project to explore and document the feasibility, benefits, and technical risk of advanced vehicle configurations and enabling technologies that will reduce the impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe that will enable the introduction of unconventional aircraft configurations that have higher lift-to-drag ratios, reduced drag, and lower community noise. Although such novel configurations like the Hybrid Wing Body (HWB) offer better aerodynamic performance as compared to traditional tube-and-wing aircraft, their blended wing shapes also pose significant new design challenges. Developing an improved structural concept that is capable of meeting the structural weight fraction allocated for these non-circular pressurized cabins is the primary obstacle in implementing large lifting-body designs. To address this challenge, researchers at NASA and The Boeing Company are working together to advance new structural concepts like the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), which is an integrally stiffened panel design that is stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. The large-scale multi-bay fuselage test article described in this paper is the final specimen in a building-block test program that was conceived to demonstrate the feasibility of meeting the structural weight goals established for the HWB pressure cabin.

Full-Scale Test and Analysis Results of a PRSEUS Fuselage Panel to Assess Damage Containment Features

NASA Technical Reports Server (NTRS)

Bergan, Andrew; Bakuckas, John G., Jr.; Lovejoy, Andrew; Jegley, Dawn; Linton, Kim; Neal, Bert; Korkosz, Gregory; Awerbuch, Jonathan; Tan, Tein-Min

2012-01-01

Integrally stitched composite technology is an area that shows promise in enhancing the structural integrity of aircraft and aerospace structures. The most recent generation of this technology is the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. The goal of the PRSEUS concept relevant to this test is to provide damage containment capability for composite structures while reducing overall structural weight. The National Aeronautics and Space Administration (NASA), the Federal Aviation Administration (FAA), and The Boeing Company have partnered in an effort to assess the damage containment features of a full-scale curved PRSEUS panel using the FAA Full-Scale Aircraft Structural Test Evaluation and Research (FASTER) facility. A single PRSEUS test panel was subjected to axial tension, internal pressure, and combined axial tension and internal pressure loads. The test results showed excellent performance of the PRSEUS concept. No growth of Barely Visible Impact Damage (BVID) was observed after ultimate loads were applied. With a two-bay notch severing the central stringer, damage was contained within the two-bay region well above the required limit load conditions. Catastrophic failure was well above the ultimate load level. Information describing the test panel and procedure has been previously presented, so this paper focuses on the experimental procedure, test results, nondestructive inspection results, and preliminary test and analysis correlation.

Arthroscopic Medial Meniscus Posterior Root Fixation Using a Modified Mason-Allen Stitch.

PubMed

Chung, Kyu Sung; Ha, Jeong Ku; Ra, Ho Jong; Kim, Jin Goo

2016-02-01

A complete radial tear of the meniscus posterior root, which can effectively cause a state of total meniscectomy via loss of hoop tension, requires that the torn root be repaired. Several methods have been used to repair medial meniscus posterior root tears, most of which are based on a simple stitch technique that is known to have stitch-holding strength. We applied a modified version of the Mason-Allen stitch technique, which is recognized as a method for rotator cuff repair surgery because its locking effect overcomes the potential weakness of simple stitches. This article introduces the medial meniscus posterior root tears repair procedure based on a modified Mason-Allen stitch technique in which 2 strands (i.e., 1 simple horizontal and 1 simple vertical stitch) are used.

Design for Manufacturing and Assembly in Apparel. Part 1. Handbook

DTIC Science & Technology

1994-02-01

reduced and the inverted pleat was eliminated to take advantage of the automatic seam stitcher . The shape and size of the side back section seam...coin pocket. The size and shape of the pocket would be designed to best utilize the equipment. An automatic dart stitcher may be utilized to stitch the...with stacker Semi-automatic serging units with stacker Automatic seaming units/profile stitchers Programmable seaming units for various operations

Design of Tailored Non-Crimp Fabrics Based on Stitching Geometry

NASA Astrophysics Data System (ADS)

Krieger, Helga; Gries, Thomas; Stapleton, Scott E.

2018-02-01

Automation of the preforming process brings up two opposing requirements for the used engineering fabric. On the one hand, the fabric requires a sufficient drapeability, or low shear stiffness, for forming into double-curved geometries; but on the other hand, the fabric requires a high form stability, or high shear stiffness, for automated handling. To meet both requirements tailored non-crimp fabrics (TNCFs) are proposed. While the stitching has little structural influence on the final part, it virtually dictates the TNCFs local capability to shear and drape over a mold during preforming. The shear stiffness of TNCFs is designed by defining the local stitching geometry. NCFs with chain stitch have a comparatively high shear stiffness and NCFs with a stitch angle close to the symmetry stitch angle have a very low shear stiffness. A method to design the component specific local stitching parameters of TNCFs is discussed. For validation of the method, NCFs with designed tailored stitching parameters were manufactured and compared to benchmark NCFs with uniform stitching parameters. The designed TNCFs showed both, generally a high form stability and in locally required zones a good drapeability, in drape experiments over an elongated hemisphere.

Effects of thermal energy harvesting on the human - clothing - environment microsystem

NASA Astrophysics Data System (ADS)

Myers, A. C.; Jur, J. S.

2017-10-01

The objective of this work is to perform an in depth investigation of garment-based thermal energy harvesting. The effect of human and environmental factors on the working efficiency of a thermal energy harvesting devices, or a thermoelectric generator (TEG), placed on the body is explored.. Variables that strongly effect the response of the TEG are as follows: skin temperature, human motion or speed, body location, environmental conditions, and the textile properties surrounding the TEG. In this study, the use of textiles for managing thermal comfort of wearable technology and energy harvesting are defined. By varying the stitch length and/or knit structure, one can manipulate the thermal conductivity of the garment in a specific location. Another method of improving TEG efficiency is through the use of a heat spreader, which increases the effective collection area of heat on the TEG hot side. Here we show the effect of a TEG on the thermal properties of a garment with regard to two knit stitches, jersey and 1 × 1 rib.

One-dimensional stitching interferometry assisted by a triple-beam interferometer

DOE PAGES

Xue, Junpeng; Huang, Lei; Gao, Bo; ...

2017-04-13

In this work, we proposed for stitching interferometry to use a triple-beam interferometer to measure both the distance and the tilt for all sub-apertures before the stitching process. The relative piston between two neighboring sub-apertures is then calculated by using the data in the overlapping area. Comparisons are made between our method, and the classical least-squares principle stitching method. Our method can improve the accuracy and repeatability of the classical stitching method when a large number of sub-aperture topographies are taken into account. Our simulations and experiments on flat and spherical mirrors indicate that our proposed method can decrease themore » influence of the interferometer error from the stitched result. The comparison of stitching system with Fizeau interferometry data is about 2 nm root mean squares and the repeatability is within ± 2.5 nm peak to valley.« less

Modeling the Influence of Stitching on Delamination Growth in Stitched Warp-Knit Composite Lap Joints

NASA Technical Reports Server (NTRS)

Glaessgen, E. H.; Raju, I. S.; Poe, C. C., Jr.

1999-01-01

The effect of stitches on the failure of a single lap joint configuration was determined in a combined experimental and analytical study. The experimental study was conducted to determine debond growth under static monotonic loading. The stitches were shown to delay the initiation of the debond and provide load transfer beyond the load necessary to completely debond the stitched lap joint. The strain energy release rates at the debond front were calculated using a finite element-based technique. Models of the unstitched configuration showed significant values of modes I and II across the width of the joint and showed that mode III is zero at the centerline but increases near the free edge. Models of the stitched configuration showed that the stitches effectively reduced mode I to zero, but had less of an effect on modes II and III.

Delamination and Stitched Failure in Stitched Composite Joints

NASA Technical Reports Server (NTRS)

Glaessgen, E. H.; Raju, I. S.; Poe, C. C., Jr.

1999-01-01

The effect of stitches on the failure of a single lap joint configuration was determined in a combined experimental and finite element study. The experimental program was conducted to determine debond growth under static monotonic loading. The stitches were shown to delay the initiation of the debond and provide load transfer beyond the load necessary to completely debond the stitched lap joint. The experimentally determined debond length vs. applied load was used as an input parameter in the finite element analysis of both configurations. The strain energy release rates at the debond from were calculated using plate finite elements. Nonlinear fastener elements were used to model the stitches and multipoint constraints were used to model the contact problem. Models of the unstitched configuration showed significant values of modes I and II across the width of the joint and showed that mode III is zero at the centerline but increases near the free edge. Models of the stitched configuration showed that the stitches were effective in reducing mode I to zero, but had less of an effect on modes II and III.

KSC-04pd0620

NASA Image and Video Library

2004-03-24

KENNEDY SPACE CENTER, FLA. -- In the Thermal Protection System Facility, Pilar Ryan, with United Space Alliance, stitches a piece of insulation blanket for Atlantis. In the foreground is a ring inside of which the blankets will be sewn to fit in the orbiter's nose cap. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

STS-121: Discovery Entry Flight Director Post Landing Press Conference

NASA Technical Reports Server (NTRS)

2006-01-01

Steve Stitch, STS-121 Entry Flight Director, and Wayne Hale, Space Shuttle Program is shown in this post landing press conference. Steve Stitch begins with discussing the following topics: 1) Weather at Kennedy Space Center; 2) Gap filler protrusion; 3) De-orbit burn; 4) Space Shuttle Landing; 5) Global Position Satellite System (GPSS) performance; and 6) Post-landing rain showers. Wayne Hale discusses external tank observations at launch and the goals that were obtained by this flight, which are to deliver 4000 pounds of scientific equipment, increase the crew members to three on the International Space Station (ISS), and repair the ISS. Questions from the press on lessons learned from the Auxiliary Power Unit (APU) leak, and flight readiness reviews are addressed.

Optimized 3D stitching algorithm for whole body SPECT based on transition error minimization (TEM)

NASA Astrophysics Data System (ADS)

Cao, Xinhua; Xu, Xiaoyin; Voss, Stephan

2017-02-01

Standard Single Photon Emission Computed Tomography (SPECT) has a limited field of view (FOV) and cannot provide a 3D image of an entire long whole body SPECT. To produce a 3D whole body SPECT image, two to five overlapped SPECT FOVs from head to foot are acquired and assembled using image stitching. Most commercial software from medical imaging manufacturers applies a direct mid-slice stitching method to avoid blurring or ghosting from 3D image blending. Due to intensity changes across the middle slice of overlapped images, direct mid-slice stitching often produces visible seams in the coronal and sagittal views and maximal intensity projection (MIP). In this study, we proposed an optimized algorithm to reduce the visibility of stitching edges. The new algorithm computed, based on transition error minimization (TEM), a 3D stitching interface between two overlapped 3D SPECT images. To test the suggested algorithm, four studies of 2-FOV whole body SPECT were used and included two different reconstruction methods (filtered back projection (FBP) and ordered subset expectation maximization (OSEM)) as well as two different radiopharmaceuticals (Tc-99m MDP for bone metastases and I-131 MIBG for neuroblastoma tumors). Relative transition errors of stitched whole body SPECT using mid-slice stitching and the TEM-based algorithm were measured for objective evaluation. Preliminary experiments showed that the new algorithm reduced the visibility of the stitching interface in the coronal, sagittal, and MIP views. Average relative transition errors were reduced from 56.7% of mid-slice stitching to 11.7% of TEM-based stitching. The proposed algorithm also avoids blurring artifacts by preserving the noise properties of the original SPECT images.

PRSEUS Pressure Cube Test Data and Response

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.

2013-01-01

NASA s Environmentally Responsible Aviation (ERA) Program is examining the hybrid wing body (HWB) aircraft, among others, in an effort to increase the fuel efficiency of commercial aircraft. The HWB design combines features of a flying wing with features of conventional transport aircraft, and has the advantage of simultaneously increasing both fuel efficiency and payload. Recent years have seen an increased focus on the structural performance of the HWB. The key structural challenge of a HWB airframe is the ability to create a cost and weight efficient, non-circular, pressurized shell. Conventional round fuselage sections react cabin pressure by hoop tension. However, the structural configuration of the HWB subjects the majority of the structural panels to bi-axial, in-plane loads in addition to the internal cabin pressure, which requires more thorough examination and analysis than conventional transport aircraft components having traditional and less complex load paths. To address this issue, while keeping structural weights low, extensive use of advanced composite materials is made. This report presents the test data and preliminary conclusions for a pressurized cube test article that utilizes Boeing's Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), and which is part of the building block approach used for HWB development.

Analyses for Debonding of Stitched Composite Sandwich Structures Using Improved Constitutive Models

NASA Technical Reports Server (NTRS)

Glaessgen, E. H.; Sleight, D. W.; Krishnamurthy, T.; Raju, I. S.

2001-01-01

A fracture mechanics analysis based on strain energy release rates is used to study the effect of stitching in bonded sandwich beam configurations. Finite elements are used to model the configurations. The stitches were modeled as discrete nonlinear spring elements with a compliance determined by experiment. The constitutive models were developed using the results of flatwise tension tests from sandwich material rather than monolithic material. The analyses show that increasing stitch stiffness, stitch density and debond length decrease strain energy release rates for a fixed applied load.

The TachoSil-Pledget stitch: towards eradication of suture hole bleeding.

PubMed

Shimamoto, Takeshi; Marui, Akira; Nishina, Takeshi; Saji, Yoshiaki; Komeda, Masashi

2008-12-01

We describe a novel suture consisting of a small piece of TachoSil (Nycomed, Copenhagen, Denmark) and a felt pledget-the TachoSil-pledget stitch-which was used to facilitate mechanical and biologic hemostasis in 5 patients undergoing aortic arch aneurysm repair. The TachoSil-pledget stitch achieved good or very good hemostasis at all 56 bleeding points to which it was applied, while 5 of 12 points to which a conventional felt-pledget stitch was applied required additional stitching or an additional hemostatic method.

16 CFR § 1630.31 - Reasonable and representative tests and recordkeeping requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... applicable, constructional units (needles, pitch, rows, shot, stitches, and weight), dye class, dyestuff... one test performed upon commencement of production, importation, or other receipt thereof, (2) at least one test performed after production, importation, or other receipt of the first 25,000 linear...

16 CFR § 1631.31 - Reasonable and representative tests and recordkeeping requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... applicable, constructional units (needles, pitch, rows, shot, stitches, and weight), dye class, dyestuff... one test performed upon commencement of production, importation, or other receipt thereof, (2) at least one test performed after production, importation, or other receipt of the first 25,000 linear...

An efficient intensity-based ready-to-use X-ray image stitcher.

PubMed

Wang, Junchen; Zhang, Xiaohui; Sun, Zhen; Yuan, Fuzhen

2018-06-14

The limited field of view of the X-ray image intensifier makes it difficult to cover a large target area with a single X-ray image. X-ray image stitching techniques have been proposed to produce a panoramic X-ray image. This paper presents an efficient intensity-based X-ray image stitcher, which does not rely on accurate C-arm motion control or auxiliary devices and hence is ready to use in clinic. The stitcher consumes sequentially captured X-ray images with overlap areas and automatically produces a panoramic image. The gradient information for optimization of image alignment is obtained using a back-propagation scheme so that it is convenient to adopt various image warping models. The proposed stitcher has the following advantages over existing methods: (1) no additional hardware modification or auxiliary markers are needed; (2) it is robust against feature-based approaches; (3) arbitrary warping models and shapes of the region of interest are supported; (4) seamless stitching is achieved using multi-band blending. Experiments have been performed to confirm the effectiveness of the proposed method. The proposed X-ray image stitcher is efficient, accurate and ready to use in clinic. Copyright © 2018 John Wiley & Sons, Ltd.

Stitch modeling of non crimp fabric in forming simulations

NASA Astrophysics Data System (ADS)

Steer, Q.; Colmars, J.; Boisse, P.

2018-05-01

The use of Non Crimp Fabric composite has increased during the last years due to cheaper cost of manufacturing and high mechanicals properties suitable for applications such as aeronautic, automotive and wind turbines. The main difference between Non Crimp Fabric (NCF) and textile reinforcement is the mean of manufacturing: where in textile fibers are woven, in NCF layers of unidirectional oriented fibers are assembled with a stitch. As a consequence, the stitch especially its geometry (stitch pattern) will have a major influence on the deformation of this type of reinforcement during forming process. Experimental campaigns on NCF samples compared to textile with the same fibers orientation have showed that the stitch affects the shear behavior of the reinforcement which is the main mode of deformation in the forming process. A description of the stitch has been implemented in a shell element for macro scale forming simulation as a first approach based on simple hypothesis. Further works are focus on the specific behavior of the stitch along the fabric and interaction with the fibers layers during shear deformation of the reinforcement and a method to implement the stitch in a more refined model of the fabric.

Damage development under compression-compression fatigue loading in a stitched uniwoven graphite/epoxy composite material

NASA Technical Reports Server (NTRS)

Vandermey, Nancy E.; Morris, Don H.; Masters, John E.

1991-01-01

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 degree or 90 degrees 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. Zero degree and 90 degree 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 compressive failure mode was transverse shear for all specimens, both in static compression and fatigue cycling effects.

A novel method for reducing gap formation in tendon repair.

PubMed

Dean, Ryan; Sethi, Paul

2018-03-01

This study investigates gap formation in tendon repair using a novel tensioning method. The novel stitch will demonstrate less gap formation than the other suture configurations tested. Porcine tendons stitched with classic Krackow stitch configurations were compared to a Krackow stitch modified with a proximal Tension-Assist Loop. Each group was cyclically loaded followed by analysis of the tendon-suture construct for gap formation. The Tension-Assist Loop group produced significantly less gap formation than each of the other stitch groups. Decreasing early gap formation may be beneficial in allowing early rehabilitation and range of motion.

16 CFR 1630.31 - Reasonable and representative tests and recordkeeping requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., constructional units (needles, pitch, rows, shot, stitches, and weight), dye class, dyestuff, dyeing application... representative tests with respect to any quality of machine-made carpets or rugs are (1) at least one test performed upon commencement of production, importation, or other receipt thereof, (2) at least one test...

16 CFR 1630.31 - Reasonable and representative tests and recordkeeping requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., constructional units (needles, pitch, rows, shot, stitches, and weight), dye class, dyestuff, dyeing application... representative tests with respect to any quality of machine-made carpets or rugs are (1) at least one test performed upon commencement of production, importation, or other receipt thereof, (2) at least one test...

16 CFR 1630.31 - Reasonable and representative tests and recordkeeping requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., constructional units (needles, pitch, rows, shot, stitches, and weight), dye class, dyestuff, dyeing application... representative tests with respect to any quality of machine-made carpets or rugs are (1) at least one test performed upon commencement of production, importation, or other receipt thereof, (2) at least one test...

16 CFR 1631.31 - Reasonable and representative tests and recordkeeping requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., constructional units (needles, pitch, rows, shot, stitches, and weight), dye class, dyestuff, dyeing application... representative tests with respect to any quality of machine-made carpets or rugs are (1) at least one test performed upon commencement of production, importation, or other receipt thereof, (2) at least one test...

16 CFR 1630.31 - Reasonable and representative tests and recordkeeping requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., constructional units (needles, pitch, rows, shot, stitches, and weight), dye class, dyestuff, dyeing application... representative tests with respect to any quality of machine-made carpets or rugs are (1) at least one test performed upon commencement of production, importation, or other receipt thereof, (2) at least one test...

16 CFR 1631.31 - Reasonable and representative tests and recordkeeping requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., constructional units (needles, pitch, rows, shot, stitches, and weight), dye class, dyestuff, dyeing application... representative tests with respect to any quality of machine-made carpets or rugs are (1) at least one test performed upon commencement of production, importation, or other receipt thereof, (2) at least one test...

16 CFR 1631.31 - Reasonable and representative tests and recordkeeping requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., constructional units (needles, pitch, rows, shot, stitches, and weight), dye class, dyestuff, dyeing application... representative tests with respect to any quality of machine-made carpets or rugs are (1) at least one test performed upon commencement of production, importation, or other receipt thereof, (2) at least one test...

16 CFR 1631.31 - Reasonable and representative tests and recordkeeping requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., constructional units (needles, pitch, rows, shot, stitches, and weight), dye class, dyestuff, dyeing application... representative tests with respect to any quality of machine-made carpets or rugs are (1) at least one test performed upon commencement of production, importation, or other receipt thereof, (2) at least one test...

Effects of temperature and humidity cycling on the strengths of textile reinforced carbon/epoxy composite materials

NASA Technical Reports Server (NTRS)

Cano, Roberto J.; Furrow, Keith W.

1993-01-01

Results are presented from an experimental evaluation of the combined effects of temperature and humidity cycling on AS4/3501-6 composites (unstitched, Kevlar 29 stitched, and S-2 glass stitched uniweave fabric) and AS4/E905L composites (2-D, S-2 glass stitched 2-D, and 3-D braided fabric). The AS4/3501-6 uniweave material had a quasi-isotropic layup, whereas the AS4/E905L materials were braided in a (+/-30 deg/0 deg)(sub s) orientation. Data presented include compression strengths and compression-compression fatigue results for uncycled composites and cycled composites (160, 480, 720, and 1280 cycles from 140 deg F at 95 percent relative humidity to -67 deg F). To observe the presence of microcracking within the laminates, photomicrographs were taken of each material type at the end of each cycling period. Microcracks were found to be more prevalent within stitched laminates, predominantly around individual stitches. The glass stitched laminates showed significant microcracking even before cycling. Less microcracking was evident in the Kevlar stitched materials, whereas the unstitched uniweave material developed microcracks only after cycling. The 3-D braid did not develop microcracks. The static compression strengths of the unstitched and Kevlar stitched uniweave materials were degraded by about 10 percent after 1280 temperature/humidity cycles, whereas the reduction in compression strength for the glass stitched uniweave was less than 3 percent. The reduction in compression strength for the glass stitched 2-D braid was less than 8 percent. The unstitched 2-D and 3-D braids did not lose strength from temperature/humidity cycling. The compression-compression fatigue properties of all six material types were not affected by temperature/humidity cycling.

Debonding of Stitched Composite Joints: Testing and Analysis

NASA Technical Reports Server (NTRS)

Glaessgen, E. H.; Raju, I. S.; Poe, C. C., Jr.

1999-01-01

The effect of stitches on the failure of a single lap joint configuration was determined in a combined experimental and analytical study. The experimental study was conducted to determine debond growth under static monotonic loading. The stitches were shown to delay the initiation ofthe debond and provide load transfer beyond the load necessary to completely debond the stitched lap joint. The strain energy release rates at the debond front were calculated using a finite element-based technique. Models of the unstitched configuration showed significant values of modes I and II across the width of the joint and showed that mode III is zero at the centerline but increases near the free edge. Models of the stitched configuration showed that the stitches effectively reduced mode I to zero, but had less of an effect on modes II and III.

Improving Strength of Postbuckled Panels Through Stitching

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.

2007-01-01

The behavior of blade-stiffened graphite-epoxy panels with impact damage is examined to determine the effect of adding through-the-thickness stitches in the stiffener flange-to-skin interface. The influence of stitches is evaluated by examining buckling and failure for panels with failure loads up to 3.5 times greater than buckling loads. Analytical and experimental results from four configurations of panel specimens are presented. For each configuration, two panels were manufactured with skin and flanges held together with through-the-thickness stitches introduced prior to resin infusion and curing and one panel was manufactured with no stitches holding the flange to the skin. No mechanical fasteners were used for the assembly of any of these panels. Panels with and without low-speed impact damage were loaded to failure in compression. Buckling and failure modes are discussed. Stitching had little effect on buckling loads but increased the failure loads of impact-damaged panels by up to 30%.

A Stereo Dual-Channel Dynamic Programming Algorithm for UAV Image Stitching

PubMed Central

Chen, Ruizhi; Zhang, Weilong; Li, Deren; Liao, Xuan; Zhang, Peng

2017-01-01

Dislocation is one of the major challenges in unmanned aerial vehicle (UAV) image stitching. In this paper, we propose a new algorithm for seamlessly stitching UAV images based on a dynamic programming approach. Our solution consists of two steps: Firstly, an image matching algorithm is used to correct the images so that they are in the same coordinate system. Secondly, a new dynamic programming algorithm is developed based on the concept of a stereo dual-channel energy accumulation. A new energy aggregation and traversal strategy is adopted in our solution, which can find a more optimal seam line for image stitching. Our algorithm overcomes the theoretical limitation of the classical Duplaquet algorithm. Experiments show that the algorithm can effectively solve the dislocation problem in UAV image stitching, especially for the cases in dense urban areas. Our solution is also direction-independent, which has better adaptability and robustness for stitching images. PMID:28885547

A Stereo Dual-Channel Dynamic Programming Algorithm for UAV Image Stitching.

PubMed

Li, Ming; Chen, Ruizhi; Zhang, Weilong; Li, Deren; Liao, Xuan; Wang, Lei; Pan, Yuanjin; Zhang, Peng

2017-09-08

Dislocation is one of the major challenges in unmanned aerial vehicle (UAV) image stitching. In this paper, we propose a new algorithm for seamlessly stitching UAV images based on a dynamic programming approach. Our solution consists of two steps: Firstly, an image matching algorithm is used to correct the images so that they are in the same coordinate system. Secondly, a new dynamic programming algorithm is developed based on the concept of a stereo dual-channel energy accumulation. A new energy aggregation and traversal strategy is adopted in our solution, which can find a more optimal seam line for image stitching. Our algorithm overcomes the theoretical limitation of the classical Duplaquet algorithm. Experiments show that the algorithm can effectively solve the dislocation problem in UAV image stitching, especially for the cases in dense urban areas. Our solution is also direction-independent, which has better adaptability and robustness for stitching images.

A method for fast automated microscope image stitching.

PubMed

Yang, Fan; Deng, Zhen-Sheng; Fan, Qiu-Hong

2013-05-01

Image stitching is an important technology to produce a panorama or larger image by combining several images with overlapped areas. In many biomedical researches, image stitching is highly desirable to acquire a panoramic image which represents large areas of certain structures or whole sections, while retaining microscopic resolution. In this study, we develop a fast normal light microscope image stitching algorithm based on feature extraction. At first, an algorithm of scale-space reconstruction of speeded-up robust features (SURF) was proposed to extract features from the images to be stitched with a short time and higher repeatability. Then, the histogram equalization (HE) method was employed to preprocess the images to enhance their contrast for extracting more features. Thirdly, the rough overlapping zones of the images preprocessed were calculated by phase correlation, and the improved SURF was used to extract the image features in the rough overlapping areas. Fourthly, the features were corresponded by matching algorithm and the transformation parameters were estimated, then the images were blended seamlessly. Finally, this procedure was applied to stitch normal light microscope images to verify its validity. Our experimental results demonstrate that the improved SURF algorithm is very robust to viewpoint, illumination, blur, rotation and zoom of the images and our method is able to stitch microscope images automatically with high precision and high speed. Also, the method proposed in this paper is applicable to registration and stitching of common images as well as stitching the microscope images in the field of virtual microscope for the purpose of observing, exchanging, saving, and establishing a database of microscope images. Copyright © 2013 Elsevier Ltd. All rights reserved.

Multi-Layer E-Textile Circuits

NASA Technical Reports Server (NTRS)

Dunne, Lucy E.; Bibeau, Kaila; Mulligan, Lucie; Frith, Ashton; Simon, Cory

2012-01-01

Stitched e-textile circuits facilitate wearable, flexible, comfortable wearable technology. However, while stitched methods of e-textile circuits are common, multi-layer circuit creation remains a challenge. Here, we present methods of stitched multi-layer circuit creation using accessible tools and techniques.

16 CFR 1616.31 - Labeling, recordkeeping, retail display and guaranties.

Code of Federal Regulations, 2014 CFR

2014-01-01

... process of manufacture of each production unit of articles of children's sleepwear, or fabrics or related... content, and details of construction on all seams, fabrics, threads, stitches, and trims used in each... sufficient to repeat the prototype tests required by § 1616.4 of the Standard for all fabrics, seams, threads...

16 CFR § 1616.31 - Labeling, recordkeeping, retail display and guaranties.

Code of Federal Regulations, 2013 CFR

2013-01-01

... process of manufacture of each production unit of articles of children's sleepwear, or fabrics or related... content, and details of construction on all seams, fabrics, threads, stitches, and trims used in each... sufficient to repeat the prototype tests required by § 1616.4 of the Standard for all fabrics, seams, threads...

16 CFR 1616.31 - Labeling, recordkeeping, retail display and guaranties.

Code of Federal Regulations, 2011 CFR

2011-01-01

... process of manufacture of each production unit of articles of children's sleepwear, or fabrics or related... content, and details of construction on all seams, fabrics, threads, stitches, and trims used in each... sufficient to repeat the prototype tests required by § 1616.4 of the Standard for all fabrics, seams, threads...

16 CFR 1616.31 - Labeling, recordkeeping, retail display and guaranties.

Code of Federal Regulations, 2012 CFR

2012-01-01

... process of manufacture of each production unit of articles of children's sleepwear, or fabrics or related... content, and details of construction on all seams, fabrics, threads, stitches, and trims used in each... sufficient to repeat the prototype tests required by § 1616.4 of the Standard for all fabrics, seams, threads...

Knitting: A Craft Makes a Comeback

ERIC Educational Resources Information Center

McIntosh, Phyllis

2011-01-01

Hand knitting is one of the most popular hobbies in the United States. Once considered the province of grannies and expectant mothers stitching layettes, knitting is enjoying a 21st century resurgence, especially among young people. Knitting, it turns out, is a trendy, often eco-friendly pastime with a wide range of appeals. And, thanks to the…

Effect of Stitching on Debonding in Composite Structural Elements

NASA Technical Reports Server (NTRS)

Raju, I. S.; Glaessgen, E. H.

2001-01-01

Stitched multiaxial warp knit materials have been suggested as viable alternatives to laminated prepreg materials for large aircraft structures such as wing skins. Analyses have been developed to quantify the effectiveness of stitching for reducing strain energy release rates in skin-stiffener debond, lap joint and sandwich debond configurations. Strain energy release rates were computed using the virtual crack closure technique. In all configurations, the stitches were shown to significantly reduce the strain energy release rate.

Effects of through-the-thickness stitching on impact and interlaminar fracture properties of textile graphite/epoxy laminates

NASA Technical Reports Server (NTRS)

Sharma, Suresh K.; Sankar, Bhavani V.

1995-01-01

This study investigated the effects of through-the-thickness stitching on impact damage resistance, impact damage tolerance, and mode I and mode II fracture toughness of textile graphite/epoxy laminates. Uniweave resin-transfer-molded 48 ply graphite/epoxy (AS4/3501-6) laminates were stitched with Kevlar and glass yarns of different linear densities and stitch spacings. Delaminations were implanted during processing to simulate impact damage. Sublaminate buckling tests were performed to determine the effects of stitching on the compressive strength. The results showed outstanding improvements of up to 400 percent in the compression strength over the unstitched laminates. In impact and static indentation tests the onset of damage occurred at the same level, but the extent of damage was less in stitched laminates. Mode I fracture toughness of 24 ply Uniweave unidirectional (AS4/3501-6) stitched laminates was measured by conducting double-cantilever-beam tests. The critical strain energy release rate (G(sub Ic)) was found to be up to 30 times higher than the unstitched laminates. Mode II fracture toughness of the Uniweave laminates was measured by performing end-notched-flexure tests. Two new methods to compute the apparent G(sub IIc) are presented. The apparent G(sub IIc) was found to be at least 5-15 times higher for the stitched laminates.

Surgical relocation of the papillary muscles in functional ischemic mitral regurgitation: what are the forces of the relocation stitches acting on the myocardium?

PubMed

Jensen, Henrik; Jensen, Morten O; Vind-Kezunovic, Stefan; Vestergaard, Rikke; Ringgaard, Steffen; Smerup, Morten H; Hønge, Jesper L; Hasenkam, J Michael; Nielsen, Sten L

2013-07-01

In patients with chronic functional ischemic mitral regurgitation (FIMR), papillary muscle relocation has the potential to induce reverse left ventricular remodeling. However, in order to optimize function and durability, the forces imposed on the left ventricular myocardium by papillary muscle relocation should be assessed. Eight pigs with FIMR were subjected to down-sized ring annuloplasty in combination with relocation of the anterior (5 mm) and posterior (15 mm) papillary muscles towards the respective trigone. Papillary muscle relocation was obtained by a 2-0 expanded polytetrafluoroethylene stitch fixed to the trigone, exteriorized through the myocardium overlying the papillary muscle, and fixed to an epicardial disc. Tension in these stitches was measured at a systolic blood pressure > 80 mmHg using a custom-made sliding caliper with a strain gauge mounted in line. This allowed assessment of the cyclic change from minimal diastolic to maximum systolic papillary muscle relocation stitch tension. Maximum cyclic change in the posterior papillary muscle (PPM) stitch tension was 1.1 N at 15 mm relocation. In comparison, the anterior papillary muscle (APM) tension was increased to a maximum of 1.4 N with only 5 mm relocation. Surprisingly, during each step of isolated PPM relocation, the APM stitch tension increased concomitantly, but in contrast APM relocation did not influence the magnitude of PPM stitch tension. There was no statistically significant difference between cyclic changes in APM and PPM stitch tension at any step of relocation. Papillary muscle relocation using stitches attached between epicardial discs and respective trigones induced a cyclic change in papillary muscle relocation stitch tension of 1.1-1.4 N. These values were in the range of normal tension in the mitral valve apparatus, and equivalent to only 19-24% of the total papillary muscle forces. Therefore, this technique does not appear to induce a non-physiologically high cyclic load on the mitral valve complex.

Progress in manufacturing large primary aircraft structures using the stitching/RTM process

NASA Technical Reports Server (NTRS)

Markus, Alan; Thrash, Patrick; Rohwer, Kim

1993-01-01

The Douglas Aircraft/NASA Act contract has been focused over the past three years at developing a materials, manufacturing, and cost base for stitched/Resin Transfer Molded (RTM) composites. The goal of the program is to develop RTM and stitching technology to provide enabling technology for application of these materials in primary aircraft structure with a high degree of confidence. Presented in this paper will be the progress to date in the area of manufacturing and associated cost values of stitched/RTM composites.

The algorithm stitching for medical imaging

NASA Astrophysics Data System (ADS)

Semenishchev, E.; Marchuk, V.; Voronin, V.; Pismenskova, M.; Tolstova, I.; Svirin, I.

2016-05-01

In this paper we propose a stitching algorithm of medical images into one. The algorithm is designed to stitching the medical x-ray imaging, biological particles in microscopic images, medical microscopic images and other. Such image can improve the diagnosis accuracy and quality for minimally invasive studies (e.g., laparoscopy, ophthalmology and other). The proposed algorithm is based on the following steps: the searching and selection areas with overlap boundaries; the keypoint and feature detection; the preliminary stitching images and transformation to reduce the visible distortion; the search a single unified borders in overlap area; brightness, contrast and white balance converting; the superimposition into a one image. Experimental results demonstrate the effectiveness of the proposed method in the task of image stitching.

Debond Analyses for Stitched Composite Structures

NASA Technical Reports Server (NTRS)

Glaessgen, E. H.; Raju, I. S.; Poe, C. C., Jr.

1998-01-01

The effect of stitching on mode I and mode II strain energy release rates for debond configurations is studied using an analysis based on plate finite elements and the virtual crack closure technique. The stitches were modeled as discrete nonlinear fastener elements with a compliance determined by experiment. The axial and shear behavior of the stitches was considered with both the compliances and failure loads assumed to be independent. The mode I strain energy release rate, G(sub I), was shown to decrease once the debond had grown beyond the first row of stitches and was reduced to zero for long debonds, however, the mode II strain energy release rate, G(sub II), continued to be of significant magnitude over the range of debond lengths considered.

3D ultrasound volume stitching using phase symmetry and harris corner detection for orthopaedic applications

NASA Astrophysics Data System (ADS)

Dalvi, Rupin; Hacihaliloglu, Ilker; Abugharbieh, Rafeef

2010-03-01

Stitching of volumes obtained from three dimensional (3D) ultrasound (US) scanners improves visualization of anatomy in many clinical applications. Fast but accurate volume registration remains the key challenge in this area.We propose a volume stitching method based on efficient registration of 3D US volumes obtained from a tracked US probe. Since the volumes, after adjusting for probe motion, are coarsely registered, we obtain salient correspondence points in the central slices of these volumes. This is done by first removing artifacts in the US slices using intensity invariant local phase image processing and then applying the Harris Corner detection algorithm. Fast sub-volume registration on a small neighborhood around the points then gives fast, accurate 3D registration parameters. The method has been tested on 3D US scans of phantom and real human radius and pelvis bones and a phantom human fetus. The method has also been compared to volumetric registration, as well as feature based registration using 3D-SIFT. Quantitative results show average post-registration error of 0.33mm which is comparable to volumetric registration accuracy (0.31mm) and much better than 3D-SIFT based registration which failed to register the volumes. The proposed method was also much faster than volumetric registration (~4.5 seconds versus 83 seconds).

MEGARA Optics: Sub-aperture Stitching Interferometry for Large Surfaces

NASA Astrophysics Data System (ADS)

Aguirre-Aguirre, Daniel; Carrasco, Esperanza; Izazaga-Pérez, Rafael; Páez, Gonzalo; Granados-Agustín, Fermín; Percino-Zacarías, Elizabeth; Gil de Paz, Armando; Gallego, Jesús; Iglesias-Páramo, Jorge; Villalobos-Mendoza, Brenda

2018-04-01

In this work, we present a detailed analysis of sub-aperture interferogram stitching software to test circular and elliptical clear apertures with diameters and long axes up to 272 and 180 mm, respectively, from the Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía (MEGARA). MEGARA is a new spectrograph for the Gran Telescopio Canarias (GTC). It offers a resolution between 6000 and 20000 via the use of volume phase holographic gratings. It has an integral field unit and a set of robots for multi-object spectroscopy at the telescope focal plane. The output end of the fibers forms the spectrograph pseudo-slit. The fixed geometry of the collimator and camera configuration requires prisms in addition to the flat windows of the volume phase holographic gratings. There are 73 optical elements of large aperture and high precision manufactured in Mexico at the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE) and the Centro de Investigaciones en Óptica (CIO). The principle of stitching interferometry is to divide the surface being tested into overlapping small sections, which allows an easier analysis (Kim & Wyant 1981). This capability is ideal for non-contact tests for unique and large optics as required by astronomical instruments. We show that the results obtained with our sub-aperture stitching algorithm were consistent with other methods that analyze the entire aperture. We used this method to analyze the 24 MEGARA prisms that could not be tested otherwise. The instrument has been successfully commissioned at GTC in all the spectral configurations. The fulfillment of the irregularity specifications was one of the necessary conditions to comply with the spectral requirements.

Systemic errors calibration in dynamic stitching interferometry

NASA Astrophysics Data System (ADS)

Wu, Xin; Qi, Te; Yu, Yingjie; Zhang, Linna

2016-05-01

The systemic error is the main error sauce in sub-aperture stitching calculation. In this paper, a systemic error calibration method is proposed based on pseudo shearing. This method is suitable in dynamic stitching interferometry for large optical plane. The feasibility is vibrated by some simulations and experiments.

Factors That Affect the Academic Success of Foreign Students at Cardinal Stritch University

ERIC Educational Resources Information Center

Annor, Peter

2010-01-01

There are limited studies in the literature on the factors that affect the academic success of foreign students in the United States. This ex post facto mixed method study investigated the factors that affect the academic success of foreign students at Cardinal Stitch University (CSU), a medium size, private university located in the Midwestern…

Stitching Stories: Re-Membering Human Enslavement in the Elementary Classroom

ERIC Educational Resources Information Center

Howard, Joy

2018-01-01

In this article, I explore this question: How can teachers, especially new teachers, create school spaces that present humanizing images and stories of people who were enslaved, particularly people of African descent in the United States? To explore this question, drawing from an ethnographic study of teachers at an elementary school in the U.S.…

Stitching-error reduction in gratings by shot-shifted electron-beam lithography

NASA Technical Reports Server (NTRS)

Dougherty, D. J.; Muller, R. E.; Maker, P. D.; Forouhar, S.

2001-01-01

Calculations of the grating spatial-frequency spectrum and the filtering properties of multiple-pass electron-beam writing demonstrate a tradeoff between stitching-error suppression and minimum pitch separation. High-resolution measurements of optical-diffraction patterns show a 25-dB reduction in stitching-error side modes.

Analytical Prediction of Damage Growth in Notched Composite Panels Loaded in Axial Compression

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.; McGowan, David M.; Davila, Carlos G.

1999-01-01

A progressive failure analysis method based on shell elements is developed for the computation of damage initiation and growth in stiffened thick-skin stitched graphite-epoxy panels loaded in axial compression. The analysis method involves a step-by-step simulation of material degradation based on ply-level failure mechanisms. High computational efficiency is derived from the use of superposed layers of shell elements to model each ply orientation in the laminate. Multiple integration points through the thickness are used to obtain the correct bending effects through the thickness without the need for ply-by-ply evaluations of the state of the material. The analysis results are compared with experimental results for three stiffened panels with notches oriented at 0, 15 and 30 degrees to the panel width dimension. A parametric study is performed to investigate the damage growth retardation characteristics of the Kevlar stitch lines in the pan

Cylinder stitching interferometry: with and without overlap regions

NASA Astrophysics Data System (ADS)

Peng, Junzheng; Chen, Dingfu; Yu, Yingjie

2017-06-01

Since the cylinder surface is closed and periodic in the azimuthal direction, existing stitching methods cannot be used to yield the 360° form map. To address this problem, this paper presents two methods for stitching interferometry of cylinder: one requires overlap regions, and the other does not need the overlap regions. For the former, we use the first order approximation of cylindrical coordinate transformation to build the stitching model. With it, the relative parameters between the adjacent sub-apertures can be calculated by the stitching model. For the latter, a set of orthogonal polynomials, termed Legendre Fourier (LF) polynomials, was developed. With these polynomials, individual sub-aperture data can be expanded as composition of inherent form of partial cylinder surface and additional misalignment parameters. Then the 360° form map can be acquired by simultaneously fitting all sub-aperture data with LF polynomials. Finally the two proposed methods are compared under various conditions. The merits and drawbacks of each stitching method are consequently revealed to provide suggestion in acquisition of 360° form map for a precision cylinder.

A novel method for rotation invariant palm print image stitching

NASA Astrophysics Data System (ADS)

Rao, Shishir Paramathma; Panetta, Karen; Agaian, Sos S.

2017-05-01

Although not as popular as fingerprint biometrics, palm prints have garnered interest in scientific community for the rich amount of distinctive information available on the palm. In this paper, a novel method for touchless palm print stitching to increase the effective area is presented. The method is not only rotation invariant but also able to robustly handle many distortions of touchless systems like illumination variations, pose variations etc. The proposed method also can handle partial palmprints, which have a high chance of occurrence in a scene of crime, by stitching them together to produce a much larger-to-full size palmprint for authentication purpose. Experiment results are shown for IIT-D palmprint database, from which pseudo partial palmprints were generated by cropping and randomly rotating them. Furthermore, the quality of stitching algorithm is determined by extensive computer simulations and visual analysis of the stitched image. Experimental results also show that the stitching significantly increases the area of palm image for feature point detection and hence provides a way to increase the accuracy and reliability of detection.

Stitching interferometry of a full cylinder without using overlap areas

NASA Astrophysics Data System (ADS)

Peng, Junzheng; Chen, Dingfu; Yu, Yingjie

2017-08-01

Traditional stitching interferometry requires finding out the overlap correspondence and computing the discrepancies in the overlap regions, which makes it complex and time-consuming to obtain the 360° form map of a cylinder. In this paper, we develop a cylinder stitching model based on a new set of orthogonal polynomials, termed Legendre Fourier (LF) polynomials. With these polynomials, individual subaperture data can be expanded as a composition of the inherent form of a partial cylinder surface and additional misalignment parameters. Then the 360° form map can be acquired by simultaneously fitting all subaperture data with the LF polynomials. A metal shaft was measured to experimentally verify the proposed method. In contrast to traditional stitching interferometry, our technique does not require overlapping of adjacent subapertures, thus significantly reducing the measurement time and making the stitching algorithm simple.

KSC-2011-1487

NASA Image and Video Library

2011-02-18

CAPE CANAVERAL, Fla. -- Members of the United States Air Force 45th Space Wing Honor Guard and more than a dozen 9/11 first responders take part in "The National 9/11 Flag" stitching ceremony in the Debus Conference Facility at the Kennedy Space Center Visitor Complex in Florida. The contributions of NASA, Kennedy Space Center and the state of Florida were stitched into the fabric of the American Flag, which was recovered near ground zero following the World Trade Center attacks on Sept. 11, 2001. The "New York Says Thank You Foundation" is taking the flag on a cross-country journey to be restored to its original 13-stripe design using pieces of fabric from American flags destined for retirement in all 50 states. Once the flag is restored, it will become a permanent collection of the National September 11 Memorial Museum being built at the World Trade Center site. Photo credit: NASA/Kim Shiflett

Accuracy and reliability of stitched cone-beam computed tomography images.

PubMed

Egbert, Nicholas; Cagna, David R; Ahuja, Swati; Wicks, Russell A

2015-03-01

This study was performed to evaluate the linear distance accuracy and reliability of stitched small field of view (FOV) cone-beam computed tomography (CBCT) reconstructed images for the fabrication of implant surgical guides. Three gutta percha points were fixed on the inferior border of a cadaveric mandible to serve as control reference points. Ten additional gutta percha points, representing fiduciary markers, were scattered on the buccal and lingual cortices at the level of the proposed complete denture flange. A digital caliper was used to measure the distance between the reference points and fiduciary markers, which represented the anatomic linear dimension. The mandible was scanned using small FOV CBCT, and the images were then reconstructed and stitched using the manufacturer's imaging software. The same measurements were then taken with the CBCT software. The anatomic linear dimension measurements and stitched small FOV CBCT measurements were statistically evaluated for linear accuracy. The mean difference between the anatomic linear dimension measurements and the stitched small FOV CBCT measurements was found to be 0.34 mm with a 95% confidence interval of +0.24 - +0.44 mm and a mean standard deviation of 0.30 mm. The difference between the control and the stitched small FOV CBCT measurements was insignificant within the parameters defined by this study. The proven accuracy of stitched small FOV CBCT data sets may allow image-guided fabrication of implant surgical stents from such data sets.

See Your State From Space!

USGS Publications Warehouse

,

2008-01-01

Each of the 50 States in the United States is beautiful in its own way. That beauty can be seen from a unique perspective using satellite images taken from high above the Earth. These State images were created from multiple satellite images stitched together into one seamless image for each State. Names of major cities, administrative boundaries, and State flags have been added.

Biomechanical evaluation of arthroscopic rotator cuff repairs: double-row compared with single-row fixation.

PubMed

Ma, C Benjamin; Comerford, Lyn; Wilson, Joseph; Puttlitz, Christian M

2006-02-01

Recent studies have shown that arthroscopic rotator cuff repairs can have higher rates of failure than do open repairs. Current methods of rotator cuff repair have been limited to single-row fixation of simple and horizontal stitches, which is very different from open repairs. The objective of this study was to compare the initial cyclic loading and load-to-failure properties of double-row fixation with those of three commonly used single-row techniques. Ten paired human supraspinatus tendons were split in half, yielding four tendons per cadaver. The bone mineral content at the greater tuberosity was assessed. Four stitch configurations (two-simple, massive cuff, arthroscopic Mason-Allen, and double-row fixation) were randomized and tested on each set of tendons. Specimens were cyclically loaded between 5 and 100 N at 0.25 Hz for fifty cycles and then loaded to failure under displacement control at 1 mm/sec. Conditioning elongation, peak-to-peak elongation, ultimate tensile load, and stiffness were measured with use of a three-dimensional tracking system and compared, and the failure type (suture or anchor pull-out) was recorded. No significant differences were found among the stitches with respect to conditioning elongation. The mean peak-to-peak elongation (and standard error of the mean) was significantly lower for the massive cuff (1.1 +/- 0.1 mm) and double-row stitches (1.1 +/- 0.1 mm) than for the arthroscopic Mason-Allen stitch (1.5 +/- 0.2 mm) (p < 0.05). The ultimate tensile load was significantly higher for double-row fixation (287 +/- 24 N) than for all of the single-row fixations (p < 0.05). Additionally, the massive cuff stitch (250 +/- 21 N) was found to have a significantly higher ultimate tensile load than the two-simple (191 +/- 18 N) and arthroscopic Mason-Allen (212 +/- 21 N) stitches (p < 0.05). No significant differences in stiffness were found among the stitches. Failure mechanisms were similar for all stitches. Rotator cuff repairs in the anterior half of the greater tuberosity had a significantly lower peak-to-peak elongation and higher ultimate tensile strength than did repairs on the posterior half. In this in vitro cadaver study, double-row fixation had a significantly higher ultimate tensile load than the three types of single-row fixation stitches. Of the single-row fixations, the massive cuff stitch had cyclic and load-to-failure characteristics similar to the double-row fixation. Anterior repairs of the supraspinatus tendon had significantly stronger biomechanical behavior than posterior repairs.

Fabrication of ф 160 mm convex hyperbolic mirror for remote sensing instrument

NASA Astrophysics Data System (ADS)

Kuo, Ching-Hsiang; Yu, Zong-Ru; Ho, Cheng-Fang; Hsu, Wei-Yao; Chen, Fong-Zhi

2012-10-01

In this study, efficient polishing processes with inspection procedures for a large convex hyperbolic mirror of Cassegrain optical system are presented. The polishing process combines the techniques of conventional lapping and CNC polishing. We apply the conventional spherical lapping process to quickly remove the sub-surface damage (SSD) layer caused by grinding process and to get the accurate radius of best-fit sphere (BFS) of aspheric surface with fine surface texture simultaneously. Thus the removed material for aspherization process can be minimized and the polishing time for SSD removal can also be reduced substantially. The inspection procedure was carried out by using phase shift interferometer with CGH and stitching technique. To acquire the real surface form error of each sub aperture, the wavefront errors of the reference flat and CGH flat due to gravity effect of the vertical setup are calibrated in advance. Subsequently, we stitch 10 calibrated sub-aperture surface form errors to establish the whole irregularity of the mirror in 160 mm diameter for correction polishing. The final result of the In this study, efficient polishing processes with inspection procedures for a large convex hyperbolic mirror of Cassegrain optical system are presented. The polishing process combines the techniques of conventional lapping and CNC polishing. We apply the conventional spherical lapping process to quickly remove the sub-surface damage (SSD) layer caused by grinding process and to get the accurate radius of best-fit sphere (BFS) of aspheric surface with fine surface texture simultaneously. Thus the removed material for aspherization process can be minimized and the polishing time for SSD removal can also be reduced substantially. The inspection procedure was carried out by using phase shift interferometer with CGH and stitching technique. To acquire the real surface form error of each sub aperture, the wavefront errors of the reference flat and CGH flat due to gravity effect of the vertical setup are calibrated in advance. Subsequently, we stitch 10 calibrated sub-aperture surface form errors to establish the whole irregularity of the mirror in 160 mm diameter for correction polishing. The final result of the Fabrication of ф160 mm Convex Hyperbolic Mirror for Remote Sensing Instrument160 mm convex hyperbolic mirror is 0.15 μm PV and 17.9 nm RMS.160 mm convex hyperbolic mirror is 0.15 μm PV and 17.9 nm RMS.

Fracture Mechanics Analysis of Stitched Stiffener-Skin Debonding

NASA Technical Reports Server (NTRS)

Glaessgen, E. H.; Raju, I. S.; Poe, C. C., Jr.

1998-01-01

An analysis based on plate finite elements and the virtual crack closure technique has been implemented to study the effect of stitching on mode I and mode II strain energy release rates for debond configurations. The stitches were modeled as discrete nonlinear fastener elements with a compliance determined by experiment. The axial and shear behavior of the stitches was considered, however, the two compliances and failure loads were assumed to be independent. Both a double cantilever beam (mode I) and a mixed mode skin-stiffener debond configuration were studied. In the double cantilever beam configurations, G(sub I) began to decrease once the debond had grown beyond the first row of stitches and was reduced to zero for long debonds. In the mixed-mode skin-stiffener configurations, G(sub I) showed a similar behavior as in the double cantilever beam configurations, however, G(sub u), continued to increase with increasing debond length.

Development and Evaluation of Stitched Sandwich Panels

NASA Technical Reports Server (NTRS)

Stanley, Larry E.; Adams, Daniel O.; Reeder, James R. (Technical Monitor)

2001-01-01

This study explored the feasibility and potential benefits provided by the addition of through-the-thickness reinforcement to sandwich structures. Through-the-thickness stitching is proposed to increase the interlaminar strength and damage tolerance of composite sandwich structures. A low-cost, out-of-autoclave processing method was developed to produce composite sandwich panels with carbon fiber face sheets, a closed-cell foam core, and through-the-thickness Kevlar stitching. The sandwich panels were stitched in a dry preform state, vacuum bagged, and infiltrated using Vacuum Assisted Resin Transfer Molding (VARTM) processing. For comparison purposes, unstitched sandwich panels were produced using the same materials and manufacturing methodology. Test panels were produced initially at the University of Utah and later at NASA Langley Research Center. Four types of mechanical tests were performed: flexural testing, flatwise tensile testing, core shear testing, and edgewise compression testing. Drop-weight impact testing followed by specimen sectioning was performed to characterize the damage resistance of stitched sandwich panels. Compression after impact (CAI) testing was performed to evaluate the damage tolerance of the sandwich panels. Results show significant increases in the flexural stiffness and strength, out-of-plane tensile strength, core shear strength, edgewise compression strength, and compression-after-impact strength of stitched sandwich structures.

Accuracy and reliability of stitched cone-beam computed tomography images

PubMed Central

Egbert, Nicholas; Cagna, David R.; Wicks, Russell A.

2015-01-01

Purpose This study was performed to evaluate the linear distance accuracy and reliability of stitched small field of view (FOV) cone-beam computed tomography (CBCT) reconstructed images for the fabrication of implant surgical guides. Materials and Methods Three gutta percha points were fixed on the inferior border of a cadaveric mandible to serve as control reference points. Ten additional gutta percha points, representing fiduciary markers, were scattered on the buccal and lingual cortices at the level of the proposed complete denture flange. A digital caliper was used to measure the distance between the reference points and fiduciary markers, which represented the anatomic linear dimension. The mandible was scanned using small FOV CBCT, and the images were then reconstructed and stitched using the manufacturer's imaging software. The same measurements were then taken with the CBCT software. Results The anatomic linear dimension measurements and stitched small FOV CBCT measurements were statistically evaluated for linear accuracy. The mean difference between the anatomic linear dimension measurements and the stitched small FOV CBCT measurements was found to be 0.34 mm with a 95% confidence interval of +0.24 - +0.44 mm and a mean standard deviation of 0.30 mm. The difference between the control and the stitched small FOV CBCT measurements was insignificant within the parameters defined by this study. Conclusion The proven accuracy of stitched small FOV CBCT data sets may allow image-guided fabrication of implant surgical stents from such data sets. PMID:25793182

Surgical Technology Integration with Tools for Cognitive Human Factors (STITCH)

DTIC Science & Technology

2007-10-01

Award Number: W81XWH-06-1-0761 TITLE: Surgical Technology Integration with Tools for Cognitive Human Factors (STITCH) PRINCIPAL INVESTIGATOR...23 JUL 2007 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Surgical Technology Integration with Tools for Cognitive Human Factors (STITCH) 5b. GRANT...by considering cognitive and environmental factors such as mental workload, stress, situation awareness, and level of comfort with complex tools

A Model Stitching Architecture for Continuous Full Flight-Envelope Simulation of Fixed-Wing Aircraft and Rotorcraft from Discrete Point Linear Models

DTIC Science & Technology

2016-04-01

incorporated with nonlinear elements to produce a continuous, quasi -nonlinear simulation model. Extrapolation methods within the model stitching architecture...Simulation Model, Quasi -Nonlinear, Piloted Simulation, Flight-Test Implications, System Identification, Off-Nominal Loading Extrapolation, Stability...incorporated with nonlinear elements to produce a continuous, quasi -nonlinear simulation model. Extrapolation methods within the model stitching

Evaluation of the impact response of textile composites

NASA Technical Reports Server (NTRS)

Portanova, M. A.

1995-01-01

An evaluation of the impact damage resistance and impact damage tolerance of stitched and unstitched uniweaves, 2-D braids, and 3-D weaves was conducted. Uniweave laminates were tested at four thicknesses to determine the sensitivity of the tests to this parameter. Several braid and weave parameters were also varied to establish their velocity (large mass) impacts and then loaded in tension or compression to measure residual strength. Experimental results indicate that stitching significantly improves the uniweaves' damage resistance. The 2-D braids and 3-D weaves offered less damage resistance than the stitched materials. Stitching also improved the compression after impact (CAI) and tension after impact (TAI) strengths of the uniweave materials.

Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging.

PubMed

Esposito, M; Anaxagoras, T; Konstantinidis, A C; Zheng, Y; Speller, R D; Evans, P M; Allinson, N M; Wells, K

2014-07-07

Recently CMOS active pixels sensors (APSs) have become a valuable alternative to amorphous silicon and selenium flat panel imagers (FPIs) in bio-medical imaging applications. CMOS APSs can now be scaled up to the standard 20 cm diameter wafer size by means of a reticle stitching block process. However, despite wafer scale CMOS APS being monolithic, sources of non-uniformity of response and regional variations can persist representing a significant challenge for wafer scale sensor response. Non-uniformity of stitched sensors can arise from a number of factors related to the manufacturing process, including variation of amplification, variation between readout components, wafer defects and process variations across the wafer due to manufacturing processes. This paper reports on an investigation into the spatial non-uniformity and regional variations of a wafer scale stitched CMOS APS. For the first time a per-pixel analysis of the electro-optical performance of a wafer CMOS APS is presented, to address inhomogeneity issues arising from the stitching techniques used to manufacture wafer scale sensors. A complete model of the signal generation in the pixel array has been provided and proved capable of accounting for noise and gain variations across the pixel array. This novel analysis leads to readout noise and conversion gain being evaluated at pixel level, stitching block level and in regions of interest, resulting in a coefficient of variation ⩽1.9%. The uniformity of the image quality performance has been further investigated in a typical x-ray application, i.e. mammography, showing a uniformity in terms of CNR among the highest when compared with mammography detectors commonly used in clinical practice. Finally, in order to compare the detection capability of this novel APS with the technology currently used (i.e. FPIs), theoretical evaluation of the detection quantum efficiency (DQE) at zero-frequency has been performed, resulting in a higher DQE for this detector compared to FPIs. Optical characterization, x-ray contrast measurements and theoretical DQE evaluation suggest that a trade off can be found between the need of a large imaging area and the requirement of a uniform imaging performance, making the DynAMITe large area CMOS APS suitable for a range of bio-medical applications.

Possibility Study of Scale Invariant Feature Transform (SIFT) Algorithm Application to Spine Magnetic Resonance Imaging

PubMed Central

Lee, Dong-Hoon; Lee, Do-Wan; Han, Bong-Soo

2016-01-01

The purpose of this study is an application of scale invariant feature transform (SIFT) algorithm to stitch the cervical-thoracic-lumbar (C-T-L) spine magnetic resonance (MR) images to provide a view of the entire spine in a single image. All MR images were acquired with fast spin echo (FSE) pulse sequence using two MR scanners (1.5 T and 3.0 T). The stitching procedures for each part of spine MR image were performed and implemented on a graphic user interface (GUI) configuration. Moreover, the stitching process is performed in two categories; manual point-to-point (mPTP) selection that performed by user specified corresponding matching points, and automated point-to-point (aPTP) selection that performed by SIFT algorithm. The stitched images using SIFT algorithm showed fine registered results and quantitatively acquired values also indicated little errors compared with commercially mounted stitching algorithm in MRI systems. Our study presented a preliminary validation of the SIFT algorithm application to MRI spine images, and the results indicated that the proposed approach can be performed well for the improvement of diagnosis. We believe that our approach can be helpful for the clinical application and extension of other medical imaging modalities for image stitching. PMID:27064404

The "Hitch Stitch": An Effective Method of Preventing Migration in High Tracheal Stenosis.

PubMed

Mehta, Ravindra M; Singla, Abhinav; Shah, Aashish; Loknath, Chakravarthi

2017-01-01

The incidence of caudal stent migration in high tracheal stenting is 13-21% and is common with silicone stents. This can lead to major problems, including emergency repeat procedures. Several antimigration methods are described, but have limitations in terms of their success rate, availability, cost or ease of the procedure. We describe an innovative method of stent migration prevention using a simple percutaneous anchoring "hitch stitch", validated in a large series. After tracheal stent placement, an Ethilon suture was passed into the stent lumen through an 18-G needle. To take this suture back to the exterior to complete the stitch, a retrieval loop was passed through another 14-G percutaneous cannula inserted into the stent lumen. Bronchoscopically, using a forceps the first suture was pulled inside the loop, the loop was retracted, the suture was exteriorized, and the knot was completed and embedded subcutaneously. While removing the stent, an endoscopic scissor was used to cut the stitch to free the stent. A total of 42 "hitch stitches" were done in 29 patients over 5 years, predominantly for silicone stents. Indications for stenting included postintubation tracheal stenosis (83.3%), malignancy (11.9%) and tracheoesophageal fistula (4.8%, metal stents). The procedure was successful in 41/42 (97.6%) patients. Stitch removal was uncomplicated. This is the largest series of an external stent anchoring procedure as a migration prevention strategy in high tracheal stenting, applicable to both silicone and metal stents. Stent migration prevention using this "hitch stitch" is simple, safe and successful, without any complications during stent removal. © 2016 S. Karger AG, Basel.

Biomechanical advantages of triple-loaded suture anchors compared with double-row rotator cuff repairs.

PubMed

Barber, F Alan; Herbert, Morley A; Schroeder, F Alexander; Aziz-Jacobo, Jorge; Mays, Matthew M; Rapley, Jay H

2010-03-01

To evaluate the strength and suture-tendon interface security of various suture anchors triply and doubly loaded with ultrahigh-molecular weight polyethylene-containing sutures and to evaluate the relative effectiveness of placing these anchors in a single-row or double-row arrangement by cyclic loading and then destructive testing. The infraspinatus muscle was reattached to the original humeral footprint by use of 1 of 5 different repair patterns in 40 bovine shoulders. Two single-row repairs and three double-row repairs were tested. High-strength sutures were used for all repairs. Five groups were studied: group 1, 2 triple-loaded screw suture anchors in a single row with simple stitches; group 2, 2 triple-loaded screw anchors in a single row with simple stitches over a fourth suture passed perpendicularly ("rip-stop" stitch); group 3, 2 medial and 2 lateral screw anchors with a single vertical mattress stitch passed from the medial anchors and 2 simple stitches passed from the lateral anchors; group 4, 2 medial double-loaded screw anchors tied in 2 mattress stitches and 2 push-in lateral anchors capturing the medial sutures in a "crisscross" spanning stitch; and group 5, 2 medial double-loaded screw anchors tied in 2 mattress stitches and 2 push-in lateral anchors creating a "suture-bridge" stitch. The specimens were cycled between 10 and 180 N at 1.0 Hz for 3,500 cycles or until failure. Endpoints were cyclic loading displacement (5 and 10 mm), total displacement, and ultimate failure load. A single row of triply loaded anchors was more resistant to stretching to a 5- and 10-mm gap than the double-row repairs with or without the addition of a rip-stop suture (P < .05). The addition of a rip-stop stitch made the repair more resistant to gap formation than a double row repair (P < .05). The crisscross double row created by 2 medial double-loaded suture anchors and 2 lateral push-in anchors stretched more than any other group (P < .05). Double-row repairs with either crossing sutures or 4 separate anchor points were more likely to fail (5- or 10-mm gap) than a single-row repair loaded with 3 simple sutures. The triple-loaded anchors with ultrahigh-molecular weight polyethylene-containing sutures placed in a single row were more resistant to stretching than the double-row groups. Copyright 2010 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Healable thermoset polymer composite embedded with stimuli-responsive fibres

PubMed Central

Li, Guoqiang; Meng, Harper; Hu, Jinlian

2012-01-01

Severe wounds in biological systems such as human skin cannot heal themselves, unless they are first stitched together. Healing of macroscopic damage in thermoset polymer composites faces a similar challenge. Stimuli-responsive shape-changing polymeric fibres with outstanding mechanical properties embedded in polymers may be able to close macro-cracks automatically upon stimulation such as heating. Here, a stimuli-responsive fibre (SRF) with outstanding mechanical properties and supercontraction capability was fabricated for the purpose of healing macroscopic damage. The SRFs and thermoplastic particles (TPs) were incorporated into regular thermosetting epoxy for repeatedly healing macroscopic damages. The system works by mimicking self-healing of biological systems such as human skin, close (stitch) then heal, i.e. close the macroscopic crack through the thermal-induced supercontraction of the SRFs, and bond the closed crack through melting and diffusing of TPs at the crack interface. The healing efficiency determined using tapered double-cantilever beam specimens was 94 per cent. The self-healing process was reasonably repeatable. PMID:22896563

Surface coverage with single vs. multiple gaze surface topography to fit scleral lenses.

PubMed

DeNaeyer, Gregory; Sanders, Donald R; Farajian, Timothy S

2017-06-01

To determine surface coverage of measurements using the sMap3D ® corneo-scleral topographer in patients presenting for scleral lens fitting. Twenty-five eyes of 23 scleral lens patients were examined. Up-gaze, straight-gaze, and down-gaze positions of each eye were "stitched" into a single map. The percentage surface coverage between 10mm and 20mm diameter circles from corneal center was compared between the straight-gaze and stitched images. Scleral toricity magnitude was calculated at 100% coverage and at the same diameter after 50% of the data was removed. At a 10mm diameter from corneal center, the straight-gaze and stitched images both had 100% coverage. At the 14, 15, 16, 18 and 20mm diameters, the straight-gaze image only covered 68%, 53%, 39%, 18%, and 6% of the ocular surface diameters while the stitched image covered 98%, 96%, 93%, 75%, and 32% respectively. In the case showing the most scleral coverage at 16mm (straight-gaze), there was only 75% coverage (straight-gaze) compared to 100% (stitched image); the case with the least coverage had 7% (straight gaze) and 92% (stitched image). The 95% limits of agreement between the 50% and 100% coverage scleral toricity was between -1.4D (50% coverage value larger) and 1.2D (100% coverage larger), a 2.6D spread. The absolute difference between 50% to 100% coverage scleral toricity was ≥0.50D in 28% and ≥1.0D in 16% of cases. It appears that a single straight-gaze image would introduce significant measurement inaccuracy in fitting scleral lenses using the sMap3D while a 3-gaze stitched image would not. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Seamless stitching of tile scan microscope images.

PubMed

Legesse, F B; Chernavskaia, O; Heuke, S; Bocklitz, T; Meyer, T; Popp, J; Heintzmann, R

2015-06-01

For diagnostic purposes, optical imaging techniques need to obtain high-resolution images of extended biological specimens in reasonable time. The field of view of an objective lens, however, is often smaller than the sample size. To image the whole sample, laser scanning microscopes acquire tile scans that are stitched into larger mosaics. The appearance of such image mosaics is affected by visible edge artefacts that arise from various optical aberrations which manifest in grey level jumps across tile boundaries. In this contribution, a technique for stitching tiles into a seamless mosaic is presented. The stitching algorithm operates by equilibrating neighbouring edges and forcing the brightness at corners to a common value. The corrected image mosaics appear to be free from stitching artefacts and are, therefore, suited for further image analysis procedures. The contribution presents a novel method to seamlessly stitch tiles captured by a laser scanning microscope into a large mosaic. The motivation for the work is the failure of currently existing methods for stitching nonlinear, multimodal images captured by our microscopic setups. Our method eliminates the visible edge artefacts that appear between neighbouring tiles by taking into account the overall illumination differences among tiles in such mosaics. The algorithm first corrects the nonuniform brightness that exists within each of the tiles. It then compensates for grey level differences across tile boundaries by equilibrating neighbouring edges and forcing the brightness at the corners to a common value. After these artefacts have been removed further image analysis procedures can be applied on the microscopic images. Even though the solution presented here is tailored for the aforementioned specific case, it could be easily adapted to other contexts where image tiles are assembled into mosaics such as in astronomical or satellite photos. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

Development of stitched/RTM composite primary structures

NASA Technical Reports Server (NTRS)

Kullerd, Susan M.; Dow, Marvin B.

1992-01-01

The goal of the NASA Advanced Composites Technology (ACT) Program is to provide the technology required to gain the full benefit of weight savings and performance offered by composite primary structures. Achieving the goal is dependent on developing composite materials and structures which are damage tolerant and economical to manufacture. Researchers at NASA LaRC and Douglas Aircraft Company are investigating stitching reinforcement combined with resin transfer molding (RTM) to create structures meeting the ACT program goals. The Douglas work is being performed under a NASA contract entitled Innovative Composites Aircraft Primary Structures (ICAPS). The research is aimed at materials, processes and structural concepts for application in both transport wings and fuselages. Empirical guidelines are being established for stitching reinforcement in primary structures. New data are presented in this paper for evaluation tests of thick (90-ply) and thin (16-ply) stitched laminates, and from selection tests of RTM composite resins. Tension strength, compression strength and post-impact compression strength data are reported. Elements of a NASA LaRC program to expand the science base for stitched/RTM composites are discussed.

Mobile and embedded fast high resolution image stitching for long length rectangular monochromatic objects with periodic structure

NASA Astrophysics Data System (ADS)

Limonova, Elena; Tropin, Daniil; Savelyev, Boris; Mamay, Igor; Nikolaev, Dmitry

2018-04-01

In this paper we describe stitching protocol, which allows to obtain high resolution images of long length monochromatic objects with periodic structure. This protocol can be used for long length documents or human-induced objects in satellite images of uninhabitable regions like Arctic regions. The length of such objects can reach notable values, while modern camera sensors have limited resolution and are not able to provide good enough image of the whole object for further processing, e.g. using in OCR system. The idea of the proposed method is to acquire a video stream containing full object in high resolution and use image stitching. We expect the scanned object to have straight boundaries and periodic structure, which allow us to introduce regularization to the stitching problem and adapt algorithm for limited computational power of mobile and embedded CPUs. With the help of detected boundaries and structure we estimate homography between frames and use this information to reduce complexity of stitching. We demonstrate our algorithm on mobile device and show image processing speed of 2 fps on Samsung Exynos 5422 processor

Experimental rotator cuff repair. A preliminary study.

PubMed

Gerber, C; Schneeberger, A G; Perren, S M; Nyffeler, R W

1999-09-01

The repair of chronic, massive rotator cuff tears is associated with a high rate of failure. Prospective studies comparing different repair techniques are difficult to design and carry out because of the many factors that influence structural and clinical outcomes. The objective of this study was to develop a suitable animal model for evaluation of the efficacy of different repair techniques for massive rotator cuff tears and to use this model to compare a new repair technique, tested in vitro, with the conventional technique. We compared two techniques of rotator cuff repair in vivo using the left shoulders of forty-seven sheep. With the conventional technique, simple stitches were used and both suture ends were passed transosseously and tied over the greater tuberosity of the humerus. With the other technique, the modified Mason-Allen stitch was used and both suture ends were passed transosseously and tied over a cortical-bone-augmentation device. This device consisted of a poly(L/D-lactide) plate that was fifteen millimeters long, ten millimeters wide, and two millimeters thick. Number-3 braided polyester suture material was used in all of the experiments. In pilot studies (without prevention of full weight-bearing), most repairs failed regardless of the technique that was used. The simple stitch always failed by the suture pulling through the tendon or the bone; the suture material did not break or tear. The modified Mason-Allen stitch failed in only two of seventeen shoulders. In ten shoulders, the suture material failed even though the stitches were intact. Thus, we concluded that the modified Mason-Allen stitch is a more secure method of achieving suture purchase in the tendon. In eight of sixteen shoulders, the nonaugmented double transosseous bone-fixation technique failed by the suture pulling through the bone. The cortical-bone-augmentation technique never failed. In definite studies, prevention of full weight-bearing was achieved by fixation of a ten-centimeter-diameter ball under the hoof of the sheep. This led to healing in eight of ten shoulders repaired with the modified Mason-Allen stitch and cortical-bone augmentation. On histological analysis, both the simple-stitch and the modified Mason-Allen technique caused similar degrees of transient localized tissue damage. Mechanical pullout tests of repairs with the new technique showed a failure strength that was approximately 30 percent of that of an intact infraspinatus tendon at six weeks, 52 percent of that of an intact tendon at three months, and 81 percent of that of an intact tendon at six months. The repair technique with a modified Mason-Allen stitch with number-3 braided polyester suture material and cortical-bone augmentation was superior to the conventional repair technique. Use of the modified Mason-Allen stitch and the cortical-bone-augmentation device transferred the weakest point of the repair to the suture material rather than to the bone or the tendon. Failure to protect the rotator cuff post-operatively was associated with an exceedingly high rate of failure, even if optimum repair technique was used. Different techniques for rotator cuff repair substantially influence the rate of failure. A modified Mason-Allen stitch does not cause tendon necrosis, and use of this stitch with cortical-bone augmentation yields a repair that is biologically well tolerated and stronger in vivo than a repair with the conventional technique. Unprotected repairs, however, have an exceedingly high rate of failure even if optimum repair technique is used. Postoperative protection from tension overload, such as with an abduction splint, may be necessary for successful healing of massive rotator cuff tears.

Modeling of Unit-Cells With Z-Pins Using FLASH: Pre-Processing and Post Processing

NASA Technical Reports Server (NTRS)

Krueger, Ronald

2005-01-01

Although the toughening properties of stitches, z-pins and similar structures have been studied extensively, investigations on the effect of z-pins on the in-plane properties of laminates are limited. A brief summary on the effect of z-pins on the in-plane tensile and compressive properties of composite laminates is presented together with a concise introduction into the finite element code FLASH. The remainder of the report illustrates the modeling aspect of unit cells with z-pins in FLASH and focuses on input and output data as well as post-processing of results.

Stitching of near-nulled subaperture measurements

NASA Technical Reports Server (NTRS)

Devries, Gary (Inventor); Brophy, Christopher (Inventor); Forbes, Greg (Inventor); Murphy, Paul (Inventor)

2012-01-01

A metrology system for measuring aspheric test objects by subaperture stitching. A wavefront-measuring gauge having a limited capture range of wavefront shapes collects partially overlapping subaperture measurements over the test object. A variable optical aberrator reshapes the measurement wavefront with between a limited number of the measurements to maintain the measurement wavefront within the capture range of the wavefront-measuring gauge. Various error compensators are incorporated into a stitching operation to manage residual errors associated with the use of the variable optical aberrator.

High-Tensile Strength Tape Versus High-Tensile Strength Suture: A Biomechanical Study.

PubMed

Gnandt, Ryan J; Smith, Jennifer L; Nguyen-Ta, Kim; McDonald, Lucas; LeClere, Lance E

2016-02-01

To determine which suture design, high-tensile strength tape or high-tensile strength suture, performed better at securing human tissue across 4 selected suture techniques commonly used in tendinous repair, by comparing the total load at failure measured during a fixed-rate longitudinal single load to failure using a biomechanical testing machine. Matched sets of tendon specimens with bony attachments were dissected from 15 human cadaveric lower extremities in a manner allowing for direct comparison testing. With the use of selected techniques (simple Mason-Allen in the patellar tendon specimens, whip stitch in the quadriceps tendon specimens, and Krackow stitch in the Achilles tendon specimens), 1 sample of each set was sutured with a 2-mm braided, nonabsorbable, high-tensile strength tape and the other with a No. 2 braided, nonabsorbable, high-tensile strength suture. A total of 120 specimens were tested. Each model was loaded to failure at a fixed longitudinal traction rate of 100 mm/min. The maximum load and failure method were recorded. In the whip stitch and the Krackow-stitch models, the high-tensile strength tape had a significantly greater mean load at failure with a difference of 181 N (P = .001) and 94 N (P = .015) respectively. No significant difference was found in the Mason-Allen and simple stitch models. Pull-through remained the most common method of failure at an overall rate of 56.7% (suture = 55%; tape = 58.3%). In biomechanical testing during a single load to failure, high-tensile strength tape performs more favorably than high-tensile strength suture, with a greater mean load to failure, in both the whip- and Krackow-stitch models. Although suture pull-through remains the most common method of failure, high-tensile strength tape requires a significantly greater load to pull-through in a whip-stitch and Krakow-stitch model. The biomechanical data obtained in the current study indicates that high-tensile strength tape may provide better repair strength compared with high-tensile strength suture at time-zero simulated testing. Published by Elsevier Inc.

Fast assembling of neuron fragments in serial 3D sections.

PubMed

Chen, Hanbo; Iascone, Daniel Maxim; da Costa, Nuno Maçarico; Lein, Ed S; Liu, Tianming; Peng, Hanchuan

2017-09-01

Reconstructing neurons from 3D image-stacks of serial sections of thick brain tissue is very time-consuming and often becomes a bottleneck in high-throughput brain mapping projects. We developed NeuronStitcher, a software suite for stitching non-overlapping neuron fragments reconstructed in serial 3D image sections. With its efficient algorithm and user-friendly interface, NeuronStitcher has been used successfully to reconstruct very large and complex human and mouse neurons.

Development of a stitched/RFI composite transport wing

NASA Technical Reports Server (NTRS)

Kropp, Yury

1995-01-01

Development of a composite wing primary structure for commercial transport aircraft is being undertaken at McDonnell Douglas under NASA contract. The focus of the program is to design and manufacture a low cost composite wing which can effectively compete with conventional metal wing structures in terms of cost, weight, and ability to withstand damage. These goals are being accomplished by utilizing the stitched/RFI manufacturing process during which the dry fiber preforms consisting of several stacks of warp-knit material are stitched together, impregnated with resin and cured. The stitched/RFI wing skin panels have exceptional damage tolerance and fatigue characteristics, are easily repairable, and can carry higher gross stress than their metal counterparts. This paper gives an overview of the program, describes the key features of the composite wing design and addresses major issues on analysis and manufacturing.

Development of stitching reinforcement for transport wing panels

NASA Technical Reports Server (NTRS)

Palmer, Raymond J.; Dow, Marvin B.; Smith, Donald L.

1991-01-01

The NASA Advanced Composites Technology (ACT) program has the objective of providing the technology required to obtain the full benefit of weight savings and performance improvements offered by composite primary aircraft structures. Achieving the objective is dependent upon developing composite materials and structures which are damage tolerant and economical to manufacture. Researchers are investigating stitching reinforcement combined with resin transfer molding to produce materials meeting the ACT program objective. Research is aimed at materials, processes, and structural concepts for application in both transport wings and fuselages, but the emphasis to date has been on wing panels. Empirical guidelines are being established for stitching reinforcement in structures designed for heavy loads. Results are presented from evaluation tests investigating stitching types, threads, and density (penetrations per square inch). Tension strength, compression strength, and compression after impact data are reported.

Reversible Venting Stitch for Fenestrating Valve-less Glaucoma Shunts.

PubMed

Akil, Handan; Vu, Priscilla Q; Nguyen, Anhtuan H; Nugent, Alexander; Chopra, Vikas; Francis, Brian A; Tan, James C

2017-12-01

The purpose of this is to describe a venting stitch modification for valveless glaucoma aqueous shunts and characterize early postoperative intraocular pressure (IOP) and glaucoma medication use following the modification. Retrospective chart review of 61 sequential patients undergoing Baerveldt glaucoma implant (BGI)-350 implantation at the Doheny Eye Institute. Twenty-four patients received a glaucoma shunt with venting stitch modification (modified BGI) and 37 patients received an unmodified shunt (BGI-only). IOP, number of glaucoma medications, and number of hypotony cases (intraocular pressure ≤5 mm Hg) were compared between the groups. T-tests were used for statistical analysis. At postoperative-day 1, mean IOP was significantly lower compared with preoperatively in the modified BGI group (14 mm Hg; reduced by 51%; P<0.0001) but not the BGI-only group (27 mm Hg; P=0.06). IOP difference between groups persisted till immediately before tube opening (P=0.005) and fewer IOP-lowering medications needed in the modified BGI group (P<0.0001). One case (4.2%) of postoperative hypotony was encountered with BGI modification, which resolved after the stitch was removed in clinic. The venting stitch valveless shunt modification allows for effective, reliable, and safe control of early postoperative IOP.

Automated reconstruction of standing posture panoramas from multi-sector long limb x-ray images

NASA Astrophysics Data System (ADS)

Miller, Linzey; Trier, Caroline; Ben-Zikri, Yehuda K.; Linte, Cristian A.

2016-03-01

Due to the digital X-ray imaging system's limited field of view, several individual sector images are required to capture the posture of an individual in standing position. These images are then "stitched together" to reconstruct the standing posture. We have created an image processing application that automates the stitching, therefore minimizing user input, optimizing workflow, and reducing human error. The application begins with pre-processing the input images by removing artifacts, filtering out isolated noisy regions, and amplifying a seamless bone edge. The resulting binary images are then registered together using a rigid-body intensity based registration algorithm. The identified registration transformations are then used to map the original sector images into the panorama image. Our method focuses primarily on the use of the anatomical content of the images to generate the panoramas as opposed to using external markers employed to aid with the alignment process. Currently, results show robust edge detection prior to registration and we have tested our approach by comparing the resulting automatically-stitched panoramas to the manually stitched panoramas in terms of registration parameters, target registration error of homologous markers, and the homogeneity of the digitally subtracted automatically- and manually-stitched images using 26 patient datasets.

Development of stitched/RTM primary structures for transport aircraft

NASA Technical Reports Server (NTRS)

Hawley, Arthur V.

1993-01-01

This report covers work accomplished in the Innovative Composite Aircraft Primary Structure (ICAPS) program. An account is given of the design criteria and philosophy that guides the development. Wing and fuselage components used as a baseline for development are described. The major thrust of the program is to achieve a major cost breakthrough through development of stitched dry preforms and resin transfer molding (RTM), and progress on these processes is reported. A full description is provided on the fabrication of the stitched RTM wing panels. Test data are presented.

Implementation and image processing of a multi-focusing bionic compound eye

NASA Astrophysics Data System (ADS)

Wang, Xin; Guo, Yongcai; Luo, Jiasai

2018-01-01

In this paper, a new BCE with multi-focusing microlens array (MLA) was proposed. The BCE consist of detachable micro-hole array (MHA), multi-focusing MLA and spherical substrate, thus allowing it to have a large FOV without crosstalk and stray light. The MHA was fabricated by the precision machining and the parameters of the microlens varied depend on the aperture of micro-hole, through which the implementation of the multi-focusing MLA was realized under the negative pressure. Without the pattern transfer and substrate reshaping, the whole fabrication method was capable of accomplishing within several minutes by using microinjection technology. Furthermore, the method is cost-effective and easy for operation, thus providing a feasible method for the mass production of the BCE. The corresponding image processing was used to realize the image stitching for the sub-image of each single microlens, which offering an integral image in large FOV. The image stitching was implemented through the overlap between the adjacent sub-images and the feature points between the adjacent sub-images were captured by the Harris point detection. By using the adaptive non-maximal suppression, numerous potential mismatching points were eliminated and the algorithm efficiency was proved effectively. Following this, the random sample consensus (RANSAC) was used for feature points matching, by which the relation of projection transformation of the image is obtained. The implementation of the accurate image matching was then realized after the smooth transition by weighted average method. Experimental results indicate that the image-stitching algorithm can be applied for the curved BCE in large field.

Measurement and Analysis of Drapeability Effects of Warp-Knit NCF with a Standardised, Automated Testing Device

NASA Astrophysics Data System (ADS)

Christ, Mirko; Miene, Andrea; Mörschel, Ulrich

2017-08-01

Characterising the drapeability of reinforcement fabrics, is one of the most sought after abilities of those designing composite processes and components. This is not surprising as composite processes are being considered in a greater range of fields and applications. Drapeability effects are formed by the irregular rearrangement of fibres. This displacement can occur within the textile plane and result in fibre disorientations, undulations and gaps or the fibres can be pushed into the third dimension - forming wrinkles or loops. To measure such effects in non-crimp fabrics, the Textechno Drapetest automatic drapeability tester was developed. To show its viability as a tool for composite engineering, a set of fabrics was chosen to show that the influence of textile design parameters on drapeability effects is now quantifiable. The Textechno Drapetest uses a sophisticated digital image analysis system to measure the position and direction of fibres and conclude from this information on the extent and intensity of drapeability effects in the textile surface. To measure effects outside the surface, i.e. wrinkles, a laser triangulation sensor is employed. The textiles were varied in the production parameters of stitch point distance in machine direction (MD) and cross direction (CD), the weight per area, and the stitch pattern (tricot and chain). The measurements showed that the new test method is capable of measuring the effects that were expected from classical test setups as well as a range of additional effects. From the results a significant influence of the stitch yarn on the formation of effects can be deduced. Especially the density of stitch points is a parameter that lets the textile producer control the behaviour of the textile when they are formed into a doubly curved three dimensional shape. To control the gap formation, however, the spacing of the stitch points in machine or in crosswise direction is also of importance with a shorter stitch length decreasing the forming of gaps more than a tighter stitch yarn pitch.

Mechanisms of compressive failure in woven composites and stitched laminates

NASA Technical Reports Server (NTRS)

Cox, B. N.; Dadkhah, M. S.; Inman, R. V.; Morris, W. L.; Schroeder, S.

1992-01-01

Stitched laminates and angle interlock woven composites have been studied in uniaxial, in-plane, monotonic compression. Failure mechanisms have been found to depend strongly on both the reinforcement architecture and the degree of constraint imposed by the loading grips. Stitched laminates show higher compressive strength, but are brittle, possessing no load bearing capacity beyond the strain for peak load. Post-mortem inspection shows a localized shear band of buckled and broken fibers, which is evidently the product of an unstably propagating kink band. Similar shear bands are found in the woven composites if the constraint of lateral displacements is weak; but, under strong constraint, damage is not localized but distributed throughout the gauge section. While the woven composites tested are weaker than the stitched laminates, they continue to bear significant loads to compressive strains of approx. 15 percent, even when most damage is confined to a shear band.

Medial Meniscal Root Avulsion: A Biomechanical Comparison of 4 Different Repair Constructs.

PubMed

Mitchell, Richard; Pitts, Ryan; Kim, Young-Mo; Matava, Matthew J

2016-01-01

To evaluate the time-zero load-to-failure strength of 4 different constructs used to repair medial meniscal root avulsions. Sixty fresh-frozen cadaveric knees with a mean age of 74 years were used for this study. Each knee was dissected to isolate the attachment of the posterior root of the medial meniscus to the tibial plateau. An Instron machine (Instron, Norwood, MA) with a custom-designed clamp was used to avulse the intact posterior meniscal root in 12 control specimens. An additional 48 specimens were tested after transection of the native meniscal root to evaluate the pullout strength of 4 different repair constructs using No. 0 FiberWire suture (Arthrex, Naples, FL): a single suture (n = 12), a double suture (n = 12), a loop stitch (n = 12), and a locking loop stitch (n = 12). Analysis of variance was used to compare load to failure and stiffness of all 4 groups; pair-wise, between-group differences were also assessed. Repair failure occurred most commonly by suture pullout in 94% of the specimens in the repair groups. For the controls, failure occurred most commonly at the meniscus-clamp interface. Failure load was highest for the control group (mean, 359.5 ± 168 N), followed in descending order by the locking loop stitch (191.4 ± 45.1 N), loop stitch (119.6 ± 55.0 N), double suture (96.2 ± 51.4 N), and single suture (58.2 ± 29.6 N). The control group was significantly stronger than 3 of the experimental groups (single suture [95% CI, 3.8 to 11.3], double suture [95% CI, 2.1 to 6.4], and loop stitch [95% CI, 2.0 to 4.5]; P < .0001) but not the locking loop stitch (P = .003; 95% CI, 1.2 to 3.2). The locking loop stitch was significantly stronger than the single suture (P < .0001; 95% CI, 2.0 to 5.4) and double suture (P = .003; 95% CI, 1.2 to 2.9). The locking loop stitch was significantly stiffer than the single suture (P < .0001; 95% CI, 3.8 to 20.3), double suture (P < .0001; 95% CI, 2.0 to 9.8), and loop stitch (P = .03; 95% CI, 1.1 to 5.5) but not significantly different from the control group (P = .93; 95% CI, 0.3 to 1.9). Age and gender had no effect on pullout strength. The results of this study show that the locking loop stitch provided time-zero load-to-failure strength that most closely approximated the strength of the native meniscal root in addition to being significantly stronger and stiffer than 3 other commonly used repair methods. The true strength of the native meniscal root is unknown based on limitations with our testing methodology. The locking loop stitch exhibited the highest load to failure and stiffness of the 4 fixation methods tested, despite the fact that none of the fixation methods replicated the strength of the intact meniscal root. It is currently unknown what strength of fixation is required for healing of meniscal root repairs. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Role of fiber-stitching in eliminating transverse fracture in cross-ply ceramic composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, T.J.; Hutchinson, J.W.

1995-12-31

A theoretical study of the feasibility of using fiber stitching to prevent transverse matrix cracking in cross-ply ceramic composites is first reported. The prototype problem solved is a curved composite beam subject to pure bending (the C-specimen), which develops a transverse tensile stress Go acting across its circumferential mid-plane. This transverse stress is cause for concern if the beam is unstitched since there is no mechanism to arrest a matrix crack once one becomes critical. Fiber stitches normal to this plane are introduced to bridge a circumferential matrix crack lying along the mid-plane of the specimen. Results are presented formore » the energy release rate of this matrix crack as a function of a nondimensional parameter characterizing the density and fiber sliding stress of the fiber stitches. A parameter is identified which assures the applicability of the classical ACK (Aveston, Cooper and Kelly) limit for a steady-state matrix crack subject to {sigma}{sub 0}. The results obtained can be used to choose the level of stitching such that transverse matrix cracking will be excluded. The second problem we address is thermal delamination in a cross-ply ceramic composite plate due to high temperature gradients applied in the thickness direction. It is shown that a preexistent crack with a size of the order of the plate thickness will propagate unstably when a moderately large through-thickness temperature gradient is enforced. The possibility of using cross-fiber stitches to suppress thermal delamination cracking is discussed.« less

Mechanics of Air-Inflated Drop-Stitch Fabric Panels Subject to Bending Loads

DTIC Science & Technology

2013-08-15

Division Newport and Navatek, Ltd. The technical reviewer was Geoffrey R. Moss (Code 1522). The authors gratefully acknowledge Martin S . Leff and...to Bending Loads 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) Paul V. Cavallaro Christopher J. Hart Ali M...Sadegh 5.d PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Naval Undersea Warfare

Design, Analysis and Testing of a PRSEUS Pressure Cube to Investigate Assembly Joints

NASA Technical Reports Server (NTRS)

Yovanof, Nicolette; Lovejoy, Andrew E.; Baraja, Jaime; Gould, Kevin

2012-01-01

Due to its potential to significantly increase fuel efficiency, the current focus of NASA's Environmentally Responsible Aviation Program is the hybrid wing body (HWB) aircraft. Due to the complex load condition that exists in HWB structure, as compared to traditional aircraft configurations, light-weight, cost-effective and manufacturable structural concepts are required to enable the HWB. The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept is one such structural concept. A building block approach for technology development of the PRSEUS concept is being conducted. As part of this approach, a PRSEUS pressure cube was developed as a risk reduction test article to examine a new integral cap joint concept. This paper describes the design, analysis and testing of the PRSEUS pressure cube test article. The pressure cube was required to withstand a 2P, 18.4 psi, overpressure load requirement. The pristine pressure cube was tested to 2.2P with no catastrophic failure. After the addition of barely visible impact damage, the cube was pressure loaded to 48 psi where catastrophic failure occurred, meeting the scale-up requirement. Comparison of pretest and posttest analyses with the cube test response agree well, and indicate that current analysis methods can be used to accurately analyze PRSEUS structure for initial failure response.

Triple/quadruple patterning layout decomposition via linear programming and iterative rounding

NASA Astrophysics Data System (ADS)

Lin, Yibo; Xu, Xiaoqing; Yu, Bei; Baldick, Ross; Pan, David Z.

2017-04-01

As the feature size of the semiconductor technology scales down to 10 nm and beyond, multiple patterning lithography (MPL) has become one of the most practical candidates for lithography, along with other emerging technologies, such as extreme ultraviolet lithography (EUVL), e-beam lithography (EBL), and directed self-assembly. Due to the delay of EUVL and EBL, triple and even quadruple patterning is considered to be used for lower metal and contact layers with tight pitches. In the process of MPL, layout decomposition is the key design stage, where a layout is split into various parts and each part is manufactured through a separate mask. For metal layers, stitching may be allowed to resolve conflicts, whereas it is forbidden for contact and via layers. We focus on the application of layout decomposition where stitching is not allowed, such as for contact and via layers. We propose a linear programming (LP) and iterative rounding solving technique to reduce the number of nonintegers in the LP relaxation problem. Experimental results show that the proposed algorithms can provide high quality decomposition solutions efficiently while introducing as few conflicts as possible.

Error reduction by combining strapdown inertial measurement units in a baseball stitch

NASA Astrophysics Data System (ADS)

Tracy, Leah

A poor musical performance is rarely due to an inferior instrument. When a device is under performing, the temptation is to find a better device or a new technology to achieve performance objectives; however, another solution may be improving how existing technology is used through a better understanding of device characteristics, i.e., learning to play the instrument better. This thesis explores improving position and attitude estimates of inertial navigation systems (INS) through an understanding of inertial sensor errors, manipulating inertial measurement units (IMUs) to reduce that error and multisensor fusion of multiple IMUs to reduce error in a GPS denied environment.

Blended-Wing-Body (BWB) Fuselage Structural Design for Weight Reduction

NASA Technical Reports Server (NTRS)

Mukhopadhyay, V.

2005-01-01

Structural analysis and design of efficient pressurized fuselage configurations for the advanced Blended-Wing-Body (BWB) flight vehicle is a challenging problem. Unlike a conventional cylindrical pressurized fuselage, stress level in a box type BWB fuselage is an order of magnitude higher, because internal pressure primarily results in bending stress instead of skin-membrane stress. In addition, resulting deformation of aerodynamic surface could significantly affect performance advantages provided by lifting body. The pressurized composite conformal multi-lobe tanks of X-33 type space vehicle also suffered from similar problem. In the earlier BWB design studies, Vaulted Ribbed Shell (VLRS), Flat Ribbed Shell (FRS); Vaulted shell Honeycomb Core (VLHC) and Flat sandwich shell Honeycomb Core (FLHC) concepts were studied. The flat and vaulted ribbed shell concepts were found most efficient. In a recent study, a set of composite sandwich panel and cross-ribbed panel were analyzed. Optimal values of rib and skin thickness, rib spacing, and panel depth were obtained for minimal weight under stress and buckling constraints. In addition, a set of efficient multi-bubble fuselage (MBF) configuration concept was developed. The special geometric configuration of this concept allows for balancing internal cabin pressure load efficiently, through membrane stress in inner-stiffened shell and inter-cabin walls, while the outer-ribbed shell prevents buckling due to external resultant compressive loads. The initial results from these approximate finite element analyses indicate progressively lower maximum stresses and deflections compared to the earlier study. However, a relative comparison of the FEM weight per unit floor area of the segment unit indicates that the unit weights are still relatively higher that the conventional B777 type cylindrical or A380 type elliptic fuselage design. Due to the manufacturing concern associated with multi-bubble fuselage, a Y braced box-type fuselage alternative with special resin-film injected (RFI) stitched carbon composite with foam-core was designed by Boeing under a NASA research contract for the 480 passenger version. It is shown that this configuration can be improved to a modified multi-bubble fuselage which has better stress distribution, for same material and dimension.

Stitch-bond parallel-gap welding for IC circuits

NASA Technical Reports Server (NTRS)

Chvostal, P.; Tuttle, J.; Vanderpool, R.

1980-01-01

Stitch-bonded flatpacks are superior to soldered dual-in-lines where size, weight, and reliability are important. Results should interest designers of packaging for complex high-reliability electronics, such as that used in security systems, industrial process control, and vehicle electronics.

Stitch in the side: causes, workup, and solutions.

PubMed

Eichner, E Randy

2006-12-01

Side stitch is an acute, localized, sharp, transient pain that occurs during exercise, most often in runners or swimmers, but also in those participating in team sports, and less often in cyclists. The pain is vexing and performance-limiting, but fleeting and benign. Three theories compete to explain it: diaphragmatic ischemia, stress on peritoneal ligaments, and irritation of the parietal peritoneum. The differential diagnosis seems broad, but the classic side stitch is so unique in its features and setting that a reasonable working diagnosis can be made from a careful history and physical examination. Practical tips, although anecdotal, offer lasting solutions.

Stitching Techniques Advance Optics Manufacturing

NASA Technical Reports Server (NTRS)

2010-01-01

Because NASA depends on the fabrication and testing of large, high-quality aspheric (nonspherical) optics for applications like the James Webb Space Telescope, it sought an improved method for measuring large aspheres. Through Small Business Innovation Research (SBIR) awards from Goddard Space Flight Center, QED Technologies, of Rochester, New York, upgraded and enhanced its stitching technology for aspheres. QED developed the SSI-A, which earned the company an R&D 100 award, and also developed a breakthrough machine tool called the aspheric stitching interferometer. The equipment is applied to advanced optics in telescopes, microscopes, cameras, medical scopes, binoculars, and photolithography."

A Study on Ultraviolet Protection of 100% Cotton Knitted Fabric: Effect of Fabric Parameters

PubMed Central

Kan, C. W.

2014-01-01

The effect of fabric parameters such as weight, thickness, and stitch density on the ultraviolet (UV) protection of knitted fabrics was studied. Different knitting structures such as plain, pineapple, lacoste, and other combinations of different knitting stitches of knit, tuck, and miss as well as half milano, full milano, half cardigan, full cardigan, 1 × 1 rib, and interlock were prepared. Experimental results revealed that weight was the most important factor that affected UV protection while thickness and stitch density were not the leading factor in determining UV protection. PMID:24955409

Non-null annular subaperture stitching interferometry for aspheric test

NASA Astrophysics Data System (ADS)

Zhang, Lei; Liu, Dong; Shi, Tu; Yang, Yongying; Chong, Shiyao; Miao, Liang; Huang, Wei; Shen, Yibing; Bai, Jian

2015-10-01

A non-null annular subaperture stitching interferometry (NASSI), combining the subaperture stitching idea and non-null test method, is proposed for steep aspheric testing. Compared with standard annular subaperture stitching interferometry (ASSI), a partial null lens (PNL) is employed as an alternative to the transmission sphere, to generate different aspherical wavefronts as the references. The coverage subaperture number would thus be reduced greatly for the better performance of aspherical wavefronts in matching the local slope of aspheric surfaces. Instead of various mathematical stitching algorithms, a simultaneous reverse optimizing reconstruction (SROR) method based on system modeling and ray tracing is proposed for full aperture figure error reconstruction. All the subaperture measurements are simulated simultaneously with a multi-configuration model in a ray-tracing program, including the interferometric system modeling and subaperture misalignments modeling. With the multi-configuration model, full aperture figure error would be extracted in form of Zernike polynomials from subapertures wavefront data by the SROR method. This method concurrently accomplishes subaperture retrace error and misalignment correction, requiring neither complex mathematical algorithms nor subaperture overlaps. A numerical simulation exhibits the comparison of the performance of the NASSI and standard ASSI, which demonstrates the high accuracy of the NASSI in testing steep aspheric. Experimental results of NASSI are shown to be in good agreement with that of Zygo® VerifireTM Asphere interferometer.

Joint Video Stitching and Stabilization from Moving Cameras.

PubMed

Guo, Heng; Liu, Shuaicheng; He, Tong; Zhu, Shuyuan; Zeng, Bing; Gabbouj, Moncef

2016-09-08

In this paper, we extend image stitching to video stitching for videos that are captured for the same scene simultaneously by multiple moving cameras. In practice, videos captured under this circumstance often appear shaky. Directly applying image stitching methods for shaking videos often suffers from strong spatial and temporal artifacts. To solve this problem, we propose a unified framework in which video stitching and stabilization are performed jointly. Specifically, our system takes several overlapping videos as inputs. We estimate both inter motions (between different videos) and intra motions (between neighboring frames within a video). Then, we solve an optimal virtual 2D camera path from all original paths. An enlarged field of view along the virtual path is finally obtained by a space-temporal optimization that takes both inter and intra motions into consideration. Two important components of this optimization are that (1) a grid-based tracking method is designed for an improved robustness, which produces features that are distributed evenly within and across multiple views, and (2) a mesh-based motion model is adopted for the handling of the scene parallax. Some experimental results are provided to demonstrate the effectiveness of our approach on various consumer-level videos and a Plugin, named "Video Stitcher" is developed at Adobe After Effects CC2015 to show the processed videos.

Sub-aperture stitching test of a cylindrical mirror with large aperture

NASA Astrophysics Data System (ADS)

Xue, Shuai; Chen, Shanyong; Shi, Feng; Lu, Jinfeng

2016-09-01

Cylindrical mirrors are key optics of high-end equipment of national defense and scientific research such as high energy laser weapons, synchrotron radiation system, etc. However, its surface error test technology develops slowly. As a result, its optical processing quality can not meet the requirements, and the developing of the associated equipment is hindered. Computer Generated-Hologram (CGH) is commonly utilized as null for testing cylindrical optics. However, since the fabrication process of CGH with large aperture is not sophisticated yet, the null test of cylindrical optics with large aperture is limited by the aperture of the CGH. Hence CGH null test combined with sub-aperture stitching method is proposed to break the limit of the aperture of CGH for testing cylindrical optics, and the design of CGH for testing cylindrical surfaces is analyzed. Besides, the misalignment aberration of cylindrical surfaces is different from that of the rotational symmetric surfaces since the special shape of cylindrical surfaces, and the existing stitching algorithm of rotational symmetric surfaces can not meet the requirements of stitching cylindrical surfaces. We therefore analyze the misalignment aberrations of cylindrical surfaces, and study the stitching algorithm for measuring cylindrical optics with large aperture. Finally we test a cylindrical mirror with large aperture to verify the validity of the proposed method.

Enhancements for digital imaging of gusset plate connections : fisheye and image stitching.

DOT National Transportation Integrated Search

2011-09-01

This report describes techniques to convert fisheye digital images of gusset plates to perspective images (defish). It also describes methods to stitch together partial images of a gusset plate into a composite of the complete gusset plate. The conve...

Ultrastructurally-smooth thick partitioning and volume stitching for larger-scale connectomics

PubMed Central

Hayworth, Kenneth J.; Xu, C. Shan; Lu, Zhiyuan; Knott, Graham W.; Fetter, Richard D.; Tapia, Juan Carlos; Lichtman, Jeff W.; Hess, Harald F.

2015-01-01

FIB-SEM has become an essential tool for studying neural tissue at resolutions below 10×10×10 nm, producing datasets superior for automatic connectome tracing. We present a technical advance, ultrathick sectioning, which reliably subdivides embedded tissue samples into chunks (20 µm thick) optimally sized and mounted for efficient, parallel FIB-SEM imaging. These chunks are imaged separately and then ‘volume stitched’ back together, producing a final 3D dataset suitable for connectome tracing. PMID:25686390

Fully automatic and reference-marker-free image stitching method for full-spine and full-leg imaging with computed radiography

NASA Astrophysics Data System (ADS)

Wang, Xiaohui; Foos, David H.; Doran, James; Rogers, Michael K.

2004-05-01

Full-leg and full-spine imaging with standard computed radiography (CR) systems requires several cassettes/storage phosphor screens to be placed in a staggered arrangement and exposed simultaneously to achieve an increased imaging area. A method has been developed that can automatically and accurately stitch the acquired sub-images without relying on any external reference markers. It can detect and correct the order, orientation, and overlap arrangement of the subimages for stitching. The automatic determination of the order, orientation, and overlap arrangement of the sub-images consists of (1) constructing a hypothesis list that includes all cassette/screen arrangements, (2) refining hypotheses based on a set of rules derived from imaging physics, (3) correlating each consecutive sub-image pair in each hypothesis and establishing an overall figure-of-merit, (4) selecting the hypothesis of maximum figure-of-merit. The stitching process requires the CR reader to over scan each CR screen so that the screen edges are completely visible in the acquired sub-images. The rotational displacement and vertical displacement between two consecutive sub-images are calculated by matching the orientation and location of the screen edge in the front image and its corresponding shadow in the back image. The horizontal displacement is estimated by maximizing the correlation function between the two image sections in the overlap region. Accordingly, the two images are stitched together. This process is repeated for the newly stitched composite image and the next consecutive sub-image until a full-image composite is created. The method has been evaluated in both phantom experiments and clinical studies. The standard deviation of image misregistration is below one image pixel.

A precise method for adjusting the optical system of laser sub-aperture

NASA Astrophysics Data System (ADS)

Song, Xing; Zhang, Xue-min; Yang, Jianfeng; Xue, Li

2018-02-01

In order to adapt to the requirement of modern astronomical observation and warfare, the resolution of the space telescope is needed to improve, sub-aperture stitching imaging technique is one method to improve the resolution, which could be used not only the foundation and space-based large optical systems, also used in laser transmission and microscopic imaging. A large aperture main mirror of sub-aperture stitching imaging system is composed of multiple sub-mirrors distributed according to certain laws. All sub-mirrors are off-axis mirror, so the alignment of sub-aperture stitching imaging system is more complicated than a single off-axis optical system. An alignment method based on auto-collimation imaging and interferometric imaging is introduced in this paper, by using this alignment method, a sub-aperture stitching imaging system which is composed of 12 sub-mirrors was assembled with high resolution, the beam coincidence precision is better than 0.01mm, and the system wave aberration is better than 0.05λ.

Validation of simultaneous reverse optimization reconstruction algorithm in a practical circular subaperture stitching interferometer

NASA Astrophysics Data System (ADS)

Zhang, Lei; Li, Dong; Liu, Yu; Liu, Jingxiao; Li, Jingsong; Yu, Benli

2017-11-01

We demonstrate the validity of the simultaneous reverse optimization reconstruction (SROR) algorithm in circular subaperture stitching interferometry (CSSI), which is previously proposed for non-null aspheric annular subaperture stitching interferometry (ASSI). The merits of the modified SROR algorithm in CSSI, such as auto retrace error correction, no need of overlap and even permission of missed coverage, are analyzed in detail in simulations and experiments. Meanwhile, a practical CSSI system is proposed for this demonstration. An optical wedge is employed to deflect the incident beam for subaperture scanning by its rotation and shift instead of the six-axis motion-control system. Also the reference path can provide variable Zernike defocus for each subaperture test, which would decrease the fringe density. Experiments validating the SROR algorithm in this CSSI is implemented with cross validation by testing of paraboloidal mirror, flat mirror and astigmatism mirror. It is an indispensable supplement in SROR application in general subaperture stitching interferometry.

The physical mechanism of successful treatment for cervical insufficiency

NASA Astrophysics Data System (ADS)

Baumer, Alexa; Amechi, Alexis; Codrington, Paige; Leftwich, Megan C.

2017-11-01

Cervical insufficiency is a medical condition during pregnancy in which the uterine cervix softens and begins to dilate before reaching full term, usually between 18 and 22 weeks gestation. It is the most common cause of second trimester pregnancy loss. One clinical technique used to treat cervical insufficiency is the cervical cerclage, a procedure to close the cervix with a purse-string stitch. There are conflicting findings on the efficacy of a cerclage, with most studies relying on statistical evidence. The purpose of this investigation is to examine the mechanical limitations of a cervical cerclage by pressurizing a stitched, synthetic cervix until rupture. A synthetic model of the cervix is generated using ultrasound images collected by clinical collaborators and fabricated with silicon to imitate physiological properties. Medical residents from The George Washington University Hospital stitch the synthetic cervixes using clinical techniques. Pressure transducers record the maximum force on the stitch before rupture. The results of this study will provide insight into the most effective clinical interventions and the mechanism of their success.

Repair Concepts as Design Constraints of a Stiffened Composite PRSEUS Panel

NASA Technical Reports Server (NTRS)

Przekop, Adam

2012-01-01

A design and analysis of a repair concept applicable to a stiffened thin-skin composite panel based on the Pultruded Rod Stitched Efficient Unitized Structure is presented. The concept is a bolted repair using metal components, so that it can easily be applied in the operational environment. The damage scenario considered is a midbay-to-midbay saw-cut with a severed stiffener, flange and skin. In a previous study several repair configurations were explored and their feasibility confirmed but refinement was needed. The present study revisits the problem under recently revised design requirements and broadens the suite of loading conditions considered. The repair assembly design is based on the critical tension loading condition and subsequently its robustness is verified for a pressure loading case. High fidelity modeling techniques such as mesh-independent definition of compliant fasteners, elastic-plastic material properties for metal parts and geometrically nonlinear solutions are utilized in the finite element analysis. The best repair design is introduced, its analysis results are presented and factors influencing the design are assessed and discussed.

a Fast Approach for Stitching of Aerial Images

NASA Astrophysics Data System (ADS)

Moussa, A.; El-Sheimy, N.

2016-06-01

The last few years have witnessed an increasing volume of aerial image data because of the extensive improvements of the Unmanned Aerial Vehicles (UAVs). These newly developed UAVs have led to a wide variety of applications. A fast assessment of the achieved coverage and overlap of the acquired images of a UAV flight mission is of great help to save the time and cost of the further steps. A fast automatic stitching of the acquired images can help to visually assess the achieved coverage and overlap during the flight mission. This paper proposes an automatic image stitching approach that creates a single overview stitched image using the acquired images during a UAV flight mission along with a coverage image that represents the count of overlaps between the acquired images. The main challenge of such task is the huge number of images that are typically involved in such scenarios. A short flight mission with image acquisition frequency of one second can capture hundreds to thousands of images. The main focus of the proposed approach is to reduce the processing time of the image stitching procedure by exploiting the initial knowledge about the images positions provided by the navigation sensors. The proposed approach also avoids solving for all the transformation parameters of all the photos together to save the expected long computation time if all the parameters were considered simultaneously. After extracting the points of interest of all the involved images using Scale-Invariant Feature Transform (SIFT) algorithm, the proposed approach uses the initial image's coordinates to build an incremental constrained Delaunay triangulation that represents the neighborhood of each image. This triangulation helps to match only the neighbor images and therefore reduces the time-consuming features matching step. The estimated relative orientation between the matched images is used to find a candidate seed image for the stitching process. The pre-estimated transformation parameters of the images are employed successively in a growing fashion to create the stitched image and the coverage image. The proposed approach is implemented and tested using the images acquired through a UAV flight mission and the achieved results are presented and discussed.

Subaperture test of wavefront error of large telescopes: error sources and stitching performance simulations

NASA Astrophysics Data System (ADS)

Chen, Shanyong; Li, Shengyi; Wang, Guilin

2014-11-01

The wavefront error of large telescopes requires to be measured to check the system quality and also estimate the misalignment of the telescope optics including the primary, the secondary and so on. It is usually realized by a focal plane interferometer and an autocollimator flat (ACF) of the same aperture with the telescope. However, it is challenging for meter class telescopes due to high cost and technological challenges in producing the large ACF. Subaperture test with a smaller ACF is hence proposed in combination with advanced stitching algorithms. Major error sources include the surface error of the ACF, misalignment of the ACF and measurement noises. Different error sources have different impacts on the wavefront error. Basically the surface error of the ACF behaves like systematic error and the astigmatism will be cumulated and enlarged if the azimuth of subapertures remains fixed. It is difficult to accurately calibrate the ACF because it suffers considerable deformation induced by gravity or mechanical clamping force. Therefore a selfcalibrated stitching algorithm is employed to separate the ACF surface error from the subaperture wavefront error. We suggest the ACF be rotated around the optical axis of the telescope for subaperture test. The algorithm is also able to correct the subaperture tip-tilt based on the overlapping consistency. Since all subaperture measurements are obtained in the same imaging plane, lateral shift of the subapertures is always known and the real overlapping points can be recognized in this plane. Therefore lateral positioning error of subapertures has no impact on the stitched wavefront. In contrast, the angular positioning error changes the azimuth of the ACF and finally changes the systematic error. We propose an angularly uneven layout of subapertures to minimize the stitching error, which is very different from our knowledge. At last, measurement noises could never be corrected but be suppressed by means of averaging and environmental control. We simulate the performance of the stitching algorithm dealing with surface error and misalignment of the ACF, and noise suppression, which provides guidelines to optomechanical design of the stitching test system.

The Medial Stitch in Transosseous-Equivalent Rotator Cuff Repair: Vertical or Horizontal Mattress?

PubMed

Montanez, Anthony; Makarewich, Christopher A; Burks, Robert T; Henninger, Heath B

2016-09-01

Despite advances in surgical technique, rotator cuff repair retears continue to occur at rates of 10%, 22%, and 57% for small, medium, and large tears, respectively. A common mode of failure in transosseous-equivalent rotator cuff repairs is tissue pullout of the medial mattress stitch. While the medial mattress stitch has been studied extensively, no studies have evaluated a vertical mattress pattern placed near the musculotendinous junction in comparison with a horizontal mattress pattern. Vertical mattress stitches will have higher load to failure and lower gapping compared with horizontal mattress stitches in a transosseous-equivalent rotator cuff repair. Controlled laboratory study. Double-row transosseous-equivalent rotator cuff repairs were performed in 9 pairs of human male cadaveric shoulders (mean age ± SD, 58 ± 10 years). One shoulder in each pair received a medial-row suture pattern using a vertical mattress stitch, and the contralateral shoulder received a horizontal mattress. Specimens were mounted in a materials testing machine and tested in uniaxial tensile deformation for cyclic loading (500 cycles at 1 Hz to 1.0 MPa of effective stress), followed by failure testing carried out at a rate of 1 mm/s. Construct gapping and applied loads were monitored continuously throughout the testing. Vertical mattress sutures were placed in 5 right and 4 left shoulders. Peak cyclic gapping did not differ between vertical (mean ± SD, 2.8 ± 1.1 mm) and horizontal mattress specimens (3.0 ± 1.2 mm) (P = .684). Vertical mattress sutures failed at higher loads compared with horizontal mattress sutures (568.9 ± 140.3 vs 451.1 ± 174.3 N; P = .025); however, there was no significant difference in failure displacement (8.0 ± 1.6 vs 6.0 ± 2.1 mm; P = .092). Failure stiffness did not differ between the suture patterns (P = .204). In transosseous-equivalent rotator cuff repairs near the musculotendinous junction, a vertical mattress suture used as the medial stitch has a higher load to failure but no difference in gapping compared with a horizontal mattress pattern. A vertical mattress suture may offer enhanced strength of repair for transosseous-equivalent repairs. © 2016 The Author(s).

Stitching-aware in-design DPT auto fixing for sub-20nm logic devices

NASA Astrophysics Data System (ADS)

Choi, Soo-Han; Sai Krishna, K. V. V. S.; Pemberton-Smith, David

2017-03-01

As the technology continues to shrink below 20nm, Double Patterning Technology (DPT) becomes one of the mandatory solutions for routing metal layers. From the view point of Place and Route (P&R), the major concerns are how to prevent DPT odd-cycles automatically without sacrificing chip area. Even though the leading-edge P&R tools have advanced algorithms to prevent DPT odd-cycles, it is very hard to prevent the localized DPT odd-cycles, especially in Engineering Change Order (ECO) routing. In the last several years, we developed In-design DPT Auto Fixing method in order to reduce localized DPT odd-cycles significantly during ECO and could achieve remarkable design Turn-Around Times (TATs). But subsequently, as the design complexity continued increasing and chip size continued decreasing, we needed a new In-design DPT Auto Fixing approach to improve the auto. fixing rate. In this paper, we present the Stitching-Aware In-design DPT Auto Fixing method for better fixing rates and smaller chip design. The previous In-design DPT Auto Fixing method detected all DPT odd-cycles and tried to remove oddcycles by increasing the adjacent space. As the metal congestions increase in the newer technology nodes, the older Auto Fixing method has limitations to increase the adjacent space between routing metals. Consequently, the auto fixing rate of older method gets worse with the introduction of the smaller design rules. With DPT stitching enablement at In-design DRC checking procedure, the new Stitching-Aware DPT Auto Fixing method detects the most critical odd-cycles and revolve the odd-cycles automatically. The accuracy of new flow ensures better usage of space in the congested areas, and helps design more smaller chips. By applying the Stitching-Aware DPT Auto Fixing method to sub-20nm logic devices, we can confirm that the auto fixing rate is improved by 2X compared with auto fixing without stitching. Additionally, by developing the better heuristic algorithm and flow for DPT stitching, we can get DPT compliant layout with the acceptable design TATs.

Stitching interferometry for ellipsoidal x-ray mirrors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yumoto, Hirokatsu, E-mail: yumoto@spring8.or.jp; Koyama, Takahisa; Matsuyama, Satoshi

2016-05-15

Ellipsoidal mirrors, which can efficiently produce a two-dimensional focusing beam with a single mirror, are superior x-ray focusing optics, especially when compared to elliptical-cylinder mirrors in the Kirkpatrick–Baez geometry. However, nano-focusing ellipsoidal mirrors are not commonly used for x-ray optics because achieving the accuracy required for the surface metrology of nano-focusing ellipsoidal mirrors is difficult due to their small radius of curvature along the short ellipsoidal axis. Here, we developed a surface metrology system for nano-focusing ellipsoidal mirrors using stitching interferometric techniques. The developed system simultaneously measures sub-aperture shapes with a microscopic interferometer and the tilt angles of the sub-aperturemore » shapes with a large Fizeau interferometer. After correcting the systematic errors included in the sub-aperture shapes, the entire mirror shape is calculated by stitching the sub-aperture shapes based on the obtained relative angles between partially overlapped sub-apertures. In this study, we developed correction methods for systematic errors in sub-aperture shapes that originated from off-axis aberrations produced in the optics of the microscopic interferometer. The systematic errors on an ellipsoidal mirror were estimated by measuring a series of tilted plane substrates and the ellipsoidal substrate. From measurements of an ellipsoidal mirror with a 3.6-mm radius of curvature at the mirror center, we obtained a measurement repeatability of 0.51 nm (root-mean-square) in an assessment area of 0.5 mm × 99.18 mm. This value satisfies the requirements for surface metrology of nano-focusing x-ray mirrors. Thus, the developed metrology system should be applicable for fabricating nano-focusing ellipsoidal mirrors.« less

Test and analysis results for composite transport fuselage and wing structures

NASA Technical Reports Server (NTRS)

Deaton, Jerry W.; Kullerd, Susan M.; Madan, Ram C.; Chen, Victor L.

1992-01-01

Automated tow placement (ATP) and stitching of dry textile composite preforms followed by resin transfer molding (RTM) are being studied as cost effective manufacturing processes for obtaining damage tolerant fuselage and wing structures for transport aircraft. Data are presented to assess the damage tolerance of ATP and RTM fuselage elements with stitched-on stiffeners from compression tests of impacted three J-stiffened panels and from stiffener pull-off tests. Data are also presented to assess the damage tolerance of RTM wing elements which had stitched skin and stiffeners from impacted single stiffener and three blade stiffened compression tests and stiffener pull-off tests.

An Approach for Stitching Satellite Images in a Bigdata Mapreduce Framework

NASA Astrophysics Data System (ADS)

Sarı, H.; Eken, S.; Sayar, A.

2017-11-01

In this study we present a two-step map/reduce framework to stitch satellite mosaic images. The proposed system enable recognition and extraction of objects whose parts falling in separate satellite mosaic images. However this is a time and resource consuming process. The major aim of the study is improving the performance of the image stitching processes by utilizing big data framework. To realize this, we first convert the images into bitmaps (first mapper) and then String formats in the forms of 255s and 0s (second mapper), and finally, find the best possible matching position of the images by a reduce function.

Micromechanics of fatigue in woven and stitched composites

NASA Technical Reports Server (NTRS)

Cox, B. N.; Dadkhah, M. S.; Inman, R. V.; Mitchell, M. R.; Morris, W. L.; Schroeder, S.

1991-01-01

The goal is to determine how microstructural factors, especially the architecture of microstructural factors, control fatigue damage in 3D reinforced polymer composites. Test materials were fabricated from various preforms, including stitched quasi-isotropic laminates, and through-the-thickness angle interlock, layer-to-layer angle interlock, and through-the-thickness stitching effect weaves. Preforms were impregnated with a tough resin by a special vacuum infiltration method. Most tests are being performed in uniaxial compression/compression loading. In all cases to date, failure has occurred not by delamination, but by shear failure, which occurs suddenly rather than by gradual macroscopic crack growth. Some theoretical aspects of bridging are also examined.

Development and characterization of self-healing carbon fabric/ionomer composite through stitched polymeric artificial muscle

NASA Astrophysics Data System (ADS)

Gabriel, Mark Joseph

Typical cracks in composite materials are hard to detect, because they may be very small or occur inside the material. This study investigates the development and characterization of carbon fiber and an ionomer, self-healing, laminate composite, enhanced with stitched artificial muscle elements. Although the carbon fiber is used as a structural reinforcement, the carbon fiber can also act as a resistive heating element in order to activate the healing elements in a Close-Then-Heal (CTH) approach. However in this study, hot air in an oven was used to activate the, SurlynRTM 8940, self-healing matrix. Artificial muscle was prepared from commercial fishing line to stitch reinforce the carbon laminate composite in the Z plane. Holes were drilled into the final composite and the muscle was stitched into the composite for active reinforcement. Differential scanning calorimetry was used to characterize the matrix and fishing line properties. The resulting smart composite was subjected to low velocity impact tests and consequential damage before healing in an oven, followed by three point bending flexure tests. Cracks in the carbon fiber reinforcement formed more easily than expected after impact because the holes were drilled to facilitate the muscle stitching. The matrix material could heal, but the reinforcement carbon could not. Several equipment issues and failures limited the amount of samples that could be created to continue testing with new parameters.

Keyhole imaging method for dynamic objects behind the occlusion area

NASA Astrophysics Data System (ADS)

Hao, Conghui; Chen, Xi; Dong, Liquan; Zhao, Yuejin; Liu, Ming; Kong, Lingqin; Hui, Mei; Liu, Xiaohua; Wu, Hong

2018-01-01

A method of keyhole imaging based on camera array is realized to obtain the video image behind a keyhole in shielded space at a relatively long distance. We get the multi-angle video images by using a 2×2 CCD camera array to take the images behind the keyhole in four directions. The multi-angle video images are saved in the form of frame sequences. This paper presents a method of video frame alignment. In order to remove the non-target area outside the aperture, we use the canny operator and morphological method to realize the edge detection of images and fill the images. The image stitching of four images is accomplished on the basis of the image stitching algorithm of two images. In the image stitching algorithm of two images, the SIFT method is adopted to accomplish the initial matching of images, and then the RANSAC algorithm is applied to eliminate the wrong matching points and to obtain a homography matrix. A method of optimizing transformation matrix is proposed in this paper. Finally, the video image with larger field of view behind the keyhole can be synthesized with image frame sequence in which every single frame is stitched. The results show that the screen of the video is clear and natural, the brightness transition is smooth. There is no obvious artificial stitching marks in the video, and it can be applied in different engineering environment .

Liquid Crystal Spatial Light Modulators for Simulating Zonal Multifocal Lenses.

PubMed

Li, Yiyu; Bradley, Arthur; Xu, Renfeng; Kollbaum, Pete S

2017-09-01

To maximize efficiency of the normally lengthy and costly multizone lens design and testing process, it is advantageous to evaluate the potential efficacy of a design as thoroughly as possible prior to lens fabrication and on-eye testing. The current work describes an ex vivo approach of optical design testing. The aim of this study was to describe a system capable of examining the optical characteristics of multizone bifocal and multifocal optics by subaperture stitching using liquid crystal technologies. A liquid crystal spatial light modulator (SLM) was incorporated in each of two channels to generate complementary subapertures by amplitude modulation. Additional trial lenses and phase plates were placed in pupil conjugate planes of either channel to integrate the desired bifocal and multifocal optics once the two optical paths were recombined. A high-resolution Shack-Hartmann aberrometer was integrated to measure the optics of the dual-channel system. Power and wavefront error maps as well as point spread functions were measured and computed for each of three multizone multifocal designs. High transmission modulation was achieved by introducing half-wavelength optical path differences to create two- and five-zone bifocal apertures. Dual-channel stitching revealed classic annular rings in the point spread functions generated from two-zone designs when the outer annular optic was defocused. However, low efficiency of the SLM prevented us from simultaneously measuring the eye + simulator aberrations, and the higher-order diffraction patterns generated by the cellular structure of the liquid crystal arrays limited the visual field to ±0.45 degrees. The system successfully simulated bifocal and multifocal simultaneous lenses allowing for future evaluation of both objective and subjective evaluation of complex optical designs. However, low efficiency and diffraction phenomena of the SLM limit the utility of this technology for simulating multizone and multifocal optics.

Stitching Footballs: Voices of Children in Sailkot, Pakistan.

ERIC Educational Resources Information Center

Marcus, Rachel; Husselbee, David; Shah, Faiz; Harper, Annie; Ali, Bahar

This report details a situation analysis of children working in football stitching around Sialkot, Pakistan. The analysis (1) examined the reasons that children work and the probable impact of eradicating children's involvement and phasing out home-based production and (2) determined a baseline for monitoring changes in children's and families'…

16 CFR 1615.31 - Labeling, recordkeeping, advertising, retail display and guaranties.

Code of Federal Regulations, 2011 CFR

2011-01-01

... records required must establish a line of continuity through the process of manufacture of each production... content, and details of construction on all seams, fabrics, threads, stitches, and trims used in each..., seams, threads, stitches, and trims used in such prototype testing, relating such samples to the records...

16 CFR 1615.31 - Labeling, recordkeeping, advertising, retail display and guaranties.

Code of Federal Regulations, 2012 CFR

2012-01-01

... records required must establish a line of continuity through the process of manufacture of each production... content, and details of construction on all seams, fabrics, threads, stitches, and trims used in each..., seams, threads, stitches, and trims used in such prototype testing, relating such samples to the records...

16 CFR 1615.31 - Labeling, recordkeeping, advertising, retail display and guaranties.

Code of Federal Regulations, 2014 CFR

2014-01-01

... records required must establish a line of continuity through the process of manufacture of each production... content, and details of construction on all seams, fabrics, threads, stitches, and trims used in each..., seams, threads, stitches, and trims used in such prototype testing, relating such samples to the records...

46 CFR 160.049-1 - Incorporation by reference.

Code of Federal Regulations, 2012 CFR

2012-10-01

... documents: (1) Federal Specifications: CCC-C-700G-Cloth, Coated, Vinyl, Coated (Artificial Leather). CCC-C-426D-Cloth, Cotton Drill. (2) Federal standard: No. 751—Stitches, Seams, and Stitchings. (3) Coast...—Cloth, Laminated, Vinyl-Nylon, High Strength, Flexible. (b) Plan. The following plan, of the issue in...

46 CFR 160.049-1 - Incorporation by reference.

Code of Federal Regulations, 2014 CFR

2014-10-01

... documents: (1) Federal Specifications: CCC-C-700G-Cloth, Coated, Vinyl, Coated (Artificial Leather). CCC-C-426D-Cloth, Cotton Drill. (2) Federal standard: No. 751—Stitches, Seams, and Stitchings. (3) Coast...—Cloth, Laminated, Vinyl-Nylon, High Strength, Flexible. (b) Plan. The following plan, of the issue in...

46 CFR 160.049-1 - Incorporation by reference.

Code of Federal Regulations, 2013 CFR

2013-10-01

... documents: (1) Federal Specifications: CCC-C-700G-Cloth, Coated, Vinyl, Coated (Artificial Leather). CCC-C-426D-Cloth, Cotton Drill. (2) Federal standard: No. 751—Stitches, Seams, and Stitchings. (3) Coast...—Cloth, Laminated, Vinyl-Nylon, High Strength, Flexible. (b) Plan. The following plan, of the issue in...

46 CFR 160.171-3 - Incorporation by reference.

Code of Federal Regulations, 2012 CFR

2012-10-01

... at the U.S. Coast Guard, Lifesaving and Fire Safety Division (CG-ENG-4), 2100 2nd St., SW., Stop 7126.... National Bureau of Standards Special Publication 440—Color, Universal Language and Dictionary of Names..., Stitches, Seams, and Stitchings, dated January 25, 1965. Underwriters Laboratories, Inc. 12 Laboratory...

46 CFR 160.171-3 - Incorporation by reference.

Code of Federal Regulations, 2011 CFR

2011-10-01

... at the U.S. Coast Guard, Lifesaving and Fire Safety Division (CG-5214), 2100 2nd St., SW., Stop 7126.... National Bureau of Standards Special Publication 440—Color, Universal Language and Dictionary of Names..., Stitches, Seams, and Stitchings, dated January 25, 1965. Underwriters Laboratories, Inc. 12 Laboratory...

In-Process Quality Control in Apparel Production: Sewing Defects

DTIC Science & Technology

1991-10-01

runout 2. unbalanced stitch, stitch length variation Operator: 1. Raw edge, ply misalignment, sewing off of garment Thread: 1. Thread damage, broken...sewing machine. Two measurements were made for each position of the handwheel. The method used for marking the wheel is described below. A special tape

46 CFR 160.005-4 - Construction.

Code of Federal Regulations, 2010 CFR

2010-10-01

...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Life Preservers, Fibrous Glass, Adult and Child (Jacket Type.... 160.005-1, Sheet 1, for adult size, and Sheet 4, for child size, joined by seams and stitching as shown on the drawing. A drawstring tunnel shall be formed by stitching a strip of the tunnel strip...

Measurement Via Optical Near-Nulling and Subaperture Stitching

NASA Technical Reports Server (NTRS)

Forbes, Greg; De Vries, Gary; Murphy, Paul; Brophy, Chris

2012-01-01

A subaperture stitching interferometer system provides near-nulling of a subaperture wavefront reflected from an object of interest over a portion of a surface of the object. A variable optical element located in the radiation path adjustably provides near-nulling to facilitate stitching of subaperture interferograms, creating an interferogram representative of the entire surface of interest. This enables testing of aspheric surfaces without null optics customized for each surface prescription. The surface shapes of objects such as lenses and other precision components are often measured with interferometry. However, interferometers have a limited capture range, and thus the test wavefront cannot be too different from the reference or the interference cannot be analyzed. Furthermore, the performance of the interferometer is usually best when the test and reference wavefronts are nearly identical (referred to as a null condition). Thus, it is necessary when performing such measurements to correct for known variations in shape to ensure that unintended variations are within the capture range of the interferometer and accurately measured. This invention is a system for nearnulling within a subaperture stitching interferometer, although in principle, the concept can be employed by wavefront measuring gauges other than interferometers. The system employs a light source for providing coherent radiation of a subaperture extent. An object of interest is placed to modify the radiation (e.g., to reflect or pass the radiation), and a variable optical element is located to interact with, and nearly null, the affected radiation. A detector or imaging device is situated to obtain interference patterns in the modified radiation. Multiple subaperture interferograms are taken and are stitched, or joined, to provide an interferogram representative of the entire surface of the object of interest. The primary aspect of the invention is the use of adjustable corrective optics in the context of subaperture stitching near-nulling interferometry, wherein a complex surface is analyzed via multiple, separate, overlapping interferograms. For complex surfaces, the problem of managing the identification and placement of corrective optics becomes even more pronounced, to the extent that in most cases the null corrector optics are specific to the particular asphere prescription and no others (i.e. another asphere requires completely different null correction optics). In principle, the near-nulling technique does not require subaperture stitching at all. Building a near-null system that is practically useful relies on two key features: simplicity and universality. If the system is too complex, it will be difficult to calibrate and model its manufacturing errors, rendering it useless as a precision metrology tool and/or prohibitively expensive. If the system is not applicable to a wide range of test parts, then it does not provide significant value over conventional null-correction technology. Subaperture stitching enables simpler and more universal near-null systems to be effective, because a fraction of a surface is necessarily less complex than the whole surface (excepting the extreme case of a fractal surface description). The technique of near-nulling can significantly enhance aspheric subaperture stitching capability by allowing the interferometer to capture a wider range of aspheres. More over, subaperture stitching is essential to a truly effective near-nulling system, since looking at a fraction of the surface keeps the wavefront complexity within the capability of a relatively simple nearnull apparatus. Furthermore, by reducing the subaperture size, the complexity of the measured wavefront can be reduced until it is within the capability of the near-null design.

The combined effect of glass buffer strips and stitching on the damage tolerance of composites

NASA Technical Reports Server (NTRS)

Kullerd, Susan M.

1993-01-01

Recent research has demonstrated that through-the-thickness stitching provides major improvements in the damage tolerance of composite laminates loaded in compression. However, the brittle nature of polymer matrix composites makes them susceptible to damage propagation, requiring special material applications and designs to limit damage growth. Glass buffer strips, embedded within laminates, have shown the potential for improving the damage tolerance of unstitched composite laminates loaded in tension. The glass buffer strips, less stiff than the surrounding carbon fibers, arrest crack growth in composites under tensile loads. The present study investigates the damage tolerance characteristics of laminates that contain both stitching and glass buffer strips.

Freeform metrology using subaperture stitching interferometry

NASA Astrophysics Data System (ADS)

Supranowitz, Chris; Lormeau, Jean-Pierre; Maloney, Chris; Murphy, Paul; Dumas, Paul

2016-11-01

As applications for freeform optics continue to grow, the need for high-precision metrology is becoming more of a necessity. Currently, coordinate measuring machines (CMM) that implement touch probes or optical probes can measure the widest ranges of shapes of freeform optics, but these measurement solutions often lack sufficient lateral resolution and accuracy. Subaperture stitching interferometry (SSI™) extends traditional Fizeau interferometry to provide accurate, high-resolution measurements of flats, spheres, and aspheres, and development is currently on-going to enable measurements of freeform surfaces. We will present recent freeform metrology results, including repeatability and cross-test data. We will also present MRF® polishing results where the stitched data was used as the input "hitmap" to the deterministic polishing process.

16 CFR § 1615.31 - Labeling, recordkeeping, advertising, retail display and guaranties.

Code of Federal Regulations, 2013 CFR

2013-01-01

... records required must establish a line of continuity through the process of manufacture of each production... content, and details of construction on all seams, fabrics, threads, stitches, and trims used in each..., seams, threads, stitches, and trims used in such prototype testing, relating such samples to the records...

Surgical Technology Integration with Tools for Cognitive Human Factors (STITCH)

DTIC Science & Technology

2008-10-24

Award Number: W81XWH-06-1-0761 TITLE: Surgical Technology Integration with Tools for Cognitive Human Factors (STITCH) PRINCIPAL INVESTIGATOR: W...COVERED (From - To) 25 Sep 2007 - 24 Sep 2008 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Surgical Technology Integration with Tools for Cognitive...8 3. Tools and Display Technology

Parallel stitching of 2D materials

DOE PAGES

Ling, Xi; Wu, Lijun; Lin, Yuxuan; ...

2016-01-27

Diverse parallel stitched 2D heterostructures, including metal–semiconductor, semiconductor–semiconductor, and insulator–semiconductor, are synthesized directly through selective “sowing” of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. Lastly, the methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.

78 FR 36749 - Determination Under the African Growth and Opportunity Act

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-19

... Benin. Articles must be ornamented in characteristic Benin or regional folk style. An article may not... synthetic fibers. Hand-woven on manually operated looms then hand or machine stitched. There [[Page 36750...-woven in manually operated looms then machine stitched together to form a wider substrate. This is a...

46 CFR 160.002-4 - Construction.

Code of Federal Regulations, 2010 CFR

2010-10-01

...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Life Preservers, Kapok, Adult and Child (Jacket Type), Models 3...-49-6-1, Sheet 1, for adult size, and Dwg. F-49-6-5, Sheet 1, for child size, joined by seams and stitching as shown on the drawing. A drawstring tunnel shall be formed by stitching a strip of the tunnel...

Triple/quadruple patterning layout decomposition via novel linear programming and iterative rounding

NASA Astrophysics Data System (ADS)

Lin, Yibo; Xu, Xiaoqing; Yu, Bei; Baldick, Ross; Pan, David Z.

2016-03-01

As feature size of the semiconductor technology scales down to 10nm and beyond, multiple patterning lithography (MPL) has become one of the most practical candidates for lithography, along with other emerging technologies such as extreme ultraviolet lithography (EUVL), e-beam lithography (EBL) and directed self assembly (DSA). Due to the delay of EUVL and EBL, triple and even quadruple patterning are considered to be used for lower metal and contact layers with tight pitches. In the process of MPL, layout decomposition is the key design stage, where a layout is split into various parts and each part is manufactured through a separate mask. For metal layers, stitching may be allowed to resolve conflicts, while it is forbidden for contact and via layers. In this paper, we focus on the application of layout decomposition where stitching is not allowed such as for contact and via layers. We propose a linear programming and iterative rounding (LPIR) solving technique to reduce the number of non-integers in the LP relaxation problem. Experimental results show that the proposed algorithms can provide high quality decomposition solutions efficiently while introducing as few conflicts as possible.

Image feature detection and extraction techniques performance evaluation for development of panorama under different light conditions

NASA Astrophysics Data System (ADS)

Patil, Venkat P.; Gohatre, Umakant B.

2018-04-01

The technique of obtaining a wider field-of-view of an image to get high resolution integrated image is normally required for development of panorama of a photographic images or scene from a sequence of part of multiple views. There are various image stitching methods developed recently. For image stitching five basic steps are adopted stitching which are Feature detection and extraction, Image registration, computing homography, image warping and Blending. This paper provides review of some of the existing available image feature detection and extraction techniques and image stitching algorithms by categorizing them into several methods. For each category, the basic concepts are first described and later on the necessary modifications made to the fundamental concepts by different researchers are elaborated. This paper also highlights about the some of the fundamental techniques for the process of photographic image feature detection and extraction methods under various illumination conditions. The Importance of Image stitching is applicable in the various fields such as medical imaging, astrophotography and computer vision. For comparing performance evaluation of the techniques used for image features detection three methods are considered i.e. ORB, SURF, HESSIAN and time required for input images feature detection is measured. Results obtained finally concludes that for daylight condition, ORB algorithm found better due to the fact that less tome is required for more features extracted where as for images under night light condition it shows that SURF detector performs better than ORB/HESSIAN detectors.

Biomechanical characteristics of the horizontal mattress stitch: implication for double-row and suture-bridge rotator cuff repair.

PubMed

Tamboli, Mallika; Mihata, Teruhisa; Hwang, James; McGarry, Michelle H; Kang, Yangmi; Lee, Thay Q

2014-03-01

We investigated the effects of bite-size horizontal mattress stitch (distance between the limbs passed through the tendon) on the biomechanical properties of the repaired tendon. We anchored 20 bovine Achilles tendons to bone using no. 2 high-strength suture and 5-mm titanium suture anchors in a mattress-suture technique. Tendons were allocated randomly into two groups of ten each to receive stitches with a 4- or 10-mm bite. Specimens underwent cyclic loading from 5 to 30 N at 1 mm/s for 30 cycles, followed by tensile testing to failure. Gap formation, tendon strain, hysteresis, stiffness, yield load, ultimate load, energy to yield load, and energy to ultimate load were compared between groups using unpaired t tests. The 4-mm group had less (p < 0.05) gap formation and less (p < 0.05) longitudinal strain than did the 10-mm group. Ultimate load (293.6 vs. 148.9 N) and energy to ultimate load (2,563 vs. 1,472 N-mm) were greater (p < 0.001) for the 10-mm group than the 4-mm group. All tendons repaired with 4-mm suturing failed at the suture-tendon interface, with sutures pulling through the tendon, whereas the suture itself failed before the tendon did in seven of the ten specimens in the 10-mm group. Whereas a 4-mm bite fixed the tendon more tightly but at the cost of decreased ultimate strength, a 10-mm bite conveyed greater ultimate strength but with increased gap and strain. These results suggest that for the conventional double-row repair, small mattress stitches provide a tighter repair, whereas large stitches are beneficial to prevent sutures from pulling through the tendon after surgery. For suture-bridge rotator cuff repair, large stitches are beneficial because the repaired tendon has a higher strength, and the slightly mobile medial knot can be tightened by lateral fixation.

Biomechanical characteristics of single-row repair in comparison to double-row repair with consideration of the suture configuration and suture material.

PubMed

Baums, M H; Buchhorn, G H; Spahn, G; Poppendieck, B; Schultz, W; Klinger, H-M

2008-11-01

The aim of the study was to evaluate the time zero mechanical properties of single- versus double-row configuration for rotator cuff repair in an animal model with consideration of the stitch technique and suture material. Thirty-two fresh-frozen sheep shoulders were randomly assigned to four repair groups: suture anchor single-row repair coupled with (1) braided, nonabsorbable polyester suture sized USP No. 2 (SRAE) or (2) braided polyblend polyethylene suture sized No. 2 (SRAH). The double-row repair was coupled with (3) USP No. 2 (DRAE) or (4) braided polyblend polyethylene suture No. 2 (DRAH). Arthroscopic Mason-Allen stitches were used (single-row) and combined with medial horizontal mattress stitches (double-row). Shoulders were cyclically loaded from 10 to 180 N. Displacement to gap formation of 5- and 10-mm at the repair site, cycles to failure, and the mode of failure were determined. The ultimate tensile strength was verified in specimens that resisted to 3,000 cycles. DRAE and DRAH had a lower frequency of 5- (P = 0.135) and 10-mm gap formation (P = 0.135). All DRAE and DRAH resisted 3,000 cycles while only three SRAE and one SRAH resisted 3,000 cycles (P < 0.001). The ultimate tensile strength in double-row specimens was significantly higher than in others (P < 0.001). There was no significant variation in using different suture material (P > 0.05). Double-row suture anchor repair with arthroscopic Mason-Allen/medial mattress stitches provides initial strength superior to single-row repair with arthroscopic Mason-Allen stitches under isometric cyclic loading as well as under ultimate loading conditions. Our results support the concept of double-row fixation with arthroscopic Mason-Allen/medial mattress stitches in rotator cuff tears with improvement of initial fixation strength and ultimate tensile load. Use of new polyblend polyethylene suture material seems not to increase the initial biomechanical aspects of the repair construct.

Avoiding early revision rhytidectomy: a biomechanical comparison of tissue plication suture techniques.

PubMed

White, Jeremy B; Barraja, Mathieu; Mengesha, Tewodros; Bose, Sumit; Ashktorab, Samaneh; Bahn, Ryan; Vallance, Ryan; Lindsey, William H

2008-12-01

Manipulation and suspension of the superficial musculoaponeurotic system (SMAS) is performed by 74% of rhytidectomy surgeons. Multiple variations in suture techniques are employed in this task, but they have never been evaluated for differences in their ability to withstand stress. To compare the biomechanical properties of two different suture techniques that are used in SMAS plications during rhytidectomy: a double-layered running locking (DRL) stitch and multiple horizontal mattress stitches. Fourteen horizontal mattress plications, in rows of six sutures, and comparable lengths of 16 DRL stitch plications of pig skin samples, were stressed using a tensometer with grip displacement increasing at a constant rate of 0.5 cm/Min. The required force to cause plication failure was recorded for each sample at three suture break points. There was no significant difference between the two groups in the force required to cause the initial suture failure. Unlike the horizontal mattress plication, an initial break seemed to cause minimal to no distortion of the DRL tissue plication. When results were normalized by the initial break forces to account for small variations in tissue properties, the force ratio required to cause a second suture break was significantly larger in the DRL group than in the horizontal mattress technique. This is evidenced by the average second to first break force ratios of 1.62 vs. 1.13 for the DRL and horizontal mattress stitches, respectively, with a P-value of .60. The mean ratios of third to first break forces for the DRL and horizontal mattress groups were 2.08 and 0.91, respectively, with a P-value of .08. The DRL stitch requires more force than the horizontal mattress stitch to cause significant failure of tissue plication. This technique may enable plastic surgeons to avoid early revision rhytidectomy due to suture failure, and to create a long-lasting, youthful cosmetic result.

Vibroacoustic Tailoring of a Rod-Stiffened Composite Fuselage Panel with Multidisciplinary Considerations

NASA Technical Reports Server (NTRS)

Allen, Albert R.; Przekop, Adam

2015-01-01

An efficient multi-objective design tailoring procedure seeking to improve the vibroacoustic performance of a fuselage panel while maintaining or reducing weight is presented. The structure considered is the pultruded rod stitched efficient unitized structure, a highly integrated composite structure concept designed for a noncylindrical, next-generation flight vehicle fuselage. Modifications to a baseline design are evaluated within a six-parameter design space including spacing, flange width, and web height for both frame and stringer substructure components. The change in sound power radiation attributed to a design change is predicted using finite-element models sized and meshed for analyses in the 500 Hz, 1 kHz, and 2 kHz octave bands. Three design studies are carried out in parallel while considering a diffuse acoustic field excitation and two types of turbulent boundary-layer excitation. Kriging surrogate models are used to reduce the computational costs of resolving the vibroacoustic and weight objective Pareto fronts. The resulting Pareto optimal designs are then evaluated under a static pressurization ultimate load to assess structural strength and stability. Results suggest that choosing alternative configurations within the considered design space can reduce weight and improve vibroacoustic performance without compromising strength and stability of the structure under the static load condition considered, but the tradeoffs are significantly influenced by the spatial characteristics of the assumed excitation field.

Panoramic cone beam computed tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang Jenghwa; Zhou Lili; Wang Song

2012-05-15

Purpose: Cone-beam computed tomography (CBCT) is the main imaging tool for image-guided radiotherapy but its functionality is limited by a small imaging volume and restricted image position (imaged at the central instead of the treatment position for peripheral lesions to avoid collisions). In this paper, the authors present the concept of ''panoramic CBCT,'' which can image patients at the treatment position with an imaging volume as large as practically needed. Methods: In this novel panoramic CBCT technique, the target is scanned sequentially from multiple view angles. For each view angle, a half scan (180 deg. + {theta}{sub cone} where {theta}{submore » cone} is the cone angle) is performed with the imaging panel positioned in any location along the beam path. The panoramic projection images of all views for the same gantry angle are then stitched together with the direct image stitching method (i.e., according to the reported imaging position) and full-fan, half-scan CBCT reconstruction is performed using the stitched projection images. To validate this imaging technique, the authors simulated cone-beam projection images of the Mathematical Cardiac Torso (MCAT) thorax phantom for three panoramic views. Gaps, repeated/missing columns, and different exposure levels were introduced between adjacent views to simulate imperfect image stitching due to uncertainties in imaging position or output fluctuation. A modified simultaneous algebraic reconstruction technique (modified SART) was developed to reconstruct CBCT images directly from the stitched projection images. As a gold standard, full-fan, full-scan (360 deg. gantry rotation) CBCT reconstructions were also performed using projection images of one imaging panel large enough to encompass the target. Contrast-to-noise ratio (CNR) and geometric distortion were evaluated to quantify the quality of reconstructed images. Monte Carlo simulations were performed to evaluate the effect of scattering on the image quality and imaging dose for both standard and panoramic CBCT. Results: Truncated images with artifacts were observed for the CBCT reconstruction using projection images of the central view only. When the image stitching was perfect, complete reconstruction was obtained for the panoramic CBCT using the modified SART with the image quality similar to the gold standard (full-scan, full-fan CBCT using one large imaging panel). Imperfect image stitching, on the other hand, lead to (streak, line, or ring) reconstruction artifacts, reduced CNR, and/or distorted geometry. Results from Monte Carlo simulations showed that, for identical imaging quality, the imaging dose was lower for the panoramic CBCT than that acquired with one large imaging panel. For the same imaging dose, the CNR of the three-view panoramic CBCT was 50% higher than that of the regular CBCT using one big panel. Conclusions: The authors have developed a panoramic CBCT technique and demonstrated with simulation data that it can image tumors of any location for patients of any size at the treatment position with comparable or less imaging dose and time. However, the image quality of this CBCT technique is sensitive to the reconstruction artifacts caused by imperfect image stitching. Better algorithms are therefore needed to improve the accuracy of image stitching for panoramic CBCT.« less

Stitching Together a Teacher's Body of Knowledge: Frankie N. Stein's ePortfolio

ERIC Educational Resources Information Center

Hopper, Timothy; Sanford, Kathy; Bonsor-Kurki, Sarah

2012-01-01

In this article the authors report on research into how an ePortfolio (eP) process can address the critique that teacher education programs offer fragmented course experiences and too often focus on narrow instrumentalist approaches emphasising the "how to" and the "what works"--implying that learning how to teach is about stitching together…

Processing and Characterization of Needled Carbon Composites

DTIC Science & Technology

2015-12-01

thickness reinforcement techniques such as Z-pinning, stitching, and tufting. This knockdown in strength is usually the result of different factors such as...laminate plane. 15. SUBJECT TERMS composite, material, needling, characterization, processing, carbon, laminate, epoxy, VARTM, through- thickness ...sacrifices of in-plane properties typically associated with through- thickness reinforcement techniques such as Z-pinning, stitching, and tufting

Evaluation of the Behavior of Technova Corporation Rod-Stiffened Stitched Compression Specimens

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.

2013-01-01

Under Space Act Agreement 1347 between NASA and Technova Corporation, Technova designed and fabricated two carbon-epoxy crippling specimens and NASA loaded them to failure in axial compression. Each specimen contained a pultruded rod stiffener which was held to the specimen skin with through-the-thickness stitches. One of these specimens was designed to be nominally the same as pultruded rod stitched specimens fabricated by Boeing under previous programs. In the other specimen, the rod was prestressed in a Technova manufacturing process to increase its ability to carrying compressive loading. Experimental results demonstrated that the specimen without prestressing carried approximately the same load as the similar Boeing specimens and that the specimen with prestressing carried significantly more load than the specimen without prestressing.

The Use of Stitching and Bioabsorbable Mesh and Glue to Combat Prolonged Air Leaks.

PubMed

Tanaka, Toshiki; Ueda, Kazuhiro; Murakami, Junichi; Hamano, Kimikazu

2018-05-15

Prolonged postoperative air leaks are associated with extended periods of postoperative hospitalization, increased hospital costs, and an increased incidence of major cardiopulmonary complications. To prevent prolonged air leaks, we used small pieces of polyglycolic acid mesh as a pledget during the stitching of air leak sites. The stitched sites were then covered with mesh and fibrin glue. This novel technique showed the highest airway pressure tolerance in an ex vivo experimental study. There were no incidents of prolonged air leak among the five clinical cases in which this technique was initially applied. A large-scale study of patients with a high risk of prolonged air leak is warranted. Copyright © 2018. Published by Elsevier Inc.

Resin transfer molding for advanced composite primary wing and fuselage structures

NASA Technical Reports Server (NTRS)

Markus, Alan

1992-01-01

The stitching and resin transfer molding (RTM) processes developed at Douglas Aircraft Co. are successfully demonstrating significant cost reductions with good damage tolerance properties. These attributes were identified as critical to application of advanced composite materials to commercial aircraft primary structures. The RTM/stitching developments, cost analyses, and test results are discussed of the NASA Advanced Composites Technology program.

Experimental investigation of active rib stitch knitted architecture for flow control applications

NASA Astrophysics Data System (ADS)

Abel, Julianna M.; Mane, Poorna; Pascoe, Benjamin; Luntz, Jonathan; Brei, Diann

2010-04-01

Actively manipulating flow characteristics around the wing can enhance the high-lift capability and reduce drag; thereby, increasing fuel economy, improving maneuverability and operation over diverse flight conditions which enables longer, more varied missions. Active knits, a novel class of cellular structural smart material actuator architectures created by continuous, interlocked loops of stranded active material, produce distributed actuation that can actively manipulate the local surface of the aircraft wing to improve flow characteristics. Rib stitch active knits actuate normal to the surface, producing span-wise discrete periodic arrays that can withstand aerodynamic forces while supplying the necessary displacement for flow control. This paper presents a preliminary experimental investigation of the pressuredisplacement actuation performance capabilities of a rib stitch active knit based upon shape memory alloy (SMA) wire. SMA rib stitch prototypes in both individual form and in stacked and nestled architectures were experimentally tested for their quasi-static load-displacement characteristics, verifying the parallel and series relationships of the architectural configurations. The various configurations tested demonstrated the potential of active knits to generate the required level of distributed surface displacements while under aerodynamic level loads for various forms of flow control.

Geometric Stitching Method for Double Cameras with Weak Convergence Geometry

NASA Astrophysics Data System (ADS)

Zhou, N.; He, H.; Bao, Y.; Yue, C.; Xing, K.; Cao, S.

2017-05-01

In this paper, a new geometric stitching method is proposed which utilizes digital elevation model (DEM)-aided block adjustment to solve relative orientation parameters for dual-camera with weak convergence geometry. A rational function model (RFM) with affine transformation is chosen as the relative orientation model. To deal with the weak geometry, a reference DEM is used in this method as an additional constraint in the block adjustment, which only calculates the planimetry coordinates of tie points (TPs). After that we can use the obtained affine transform coefficients to generate virtual grid, and update rational polynomial coefficients (RPCs) to complete the geometric stitching. Our proposed method was tested on GaoFen-2(GF-2) dual-camera panchromatic (PAN) images. The test results show that the proposed method can achieve an accuracy of better than 0.5 pixel in planimetry and have a seamless visual effect. For regions with small relief, when global DEM with 1 km grid, SRTM with 90 m grid and ASTER GDEM V2 with 30 m grid replaced DEM with 1m grid as elevation constraint it is almost no loss of accuracy. The test results proved the effectiveness and feasibility of the stitching method.

Evaluation of a MMW active through-the-wall surveillance system

NASA Astrophysics Data System (ADS)

Currie, Nicholas C.; Stiefvater, Kenneth

2002-08-01

This paper discusses the TWS data collected with a state-of- the-art 100 GHz radar imager developed for law enforcement use by Millivision, PPC. The system collects a cube of data consisting of 16 azimuth elements by 16 elevation elements by 256 range elements. The cube represents 11 degrees by 11 degrees by 25 m of coverage. The relatively narrow field-of- view (fov) was extended by physically moving the antenna in 11 degree segments and collecting data which is stitched together into larger images, e.g. a 3X3 stitched image represents 33 degrees by 33 degrees by 26 m of coverage. Unfortunately, this stitching process required up to 5 minutes to collect a single (3X3) stitched image. Thus, motion had to be simulated. The paper will discuss the phenomenology of the MMW radar return from various objects including walls, wall-corners, desks and other furniture, and persons simulating walking. Successive frames from a simulated move of a man and woman walking will be presented, and the actual movie shown at the presentation. Comments will be offered as to the practicality of active MMW imaging for TWS application.

Testing and Analysis Validation of a Metallic Repair Applied to a PRSEUS Tension Panel

NASA Technical Reports Server (NTRS)

Przekop, Adam; Jegley, Dawn C.

2013-01-01

A design and analysis of a repair concept applicable to a stiffened composite panel based on the Pultruded Rod Stitched Efficient Unitized Structure was recently completed. The damage scenario considered was a midbay-to-midbay saw-cut with a severed stiffener, flange and skin. Advanced modeling techniques such as mesh-independent definition of compliant fasteners and elastic-plastic material properties for metal parts were utilized in the finite element analysis supporting the design effort. A bolted metallic repair was selected so that it could be easily applied in the operational environment. The present work describes results obtained from a tension panel test conducted to validate both the repair concept and finite element analysis techniques used in the design effort. The test proved that the proposed repair concept is capable of sustaining load levels that are higher than those resulting from the current working stress allowables. This conclusion enables upward revision of the stress allowables that had been kept at an overly-conservative level due to concerns associated with repairability of the panels. Correlation of test data with finite element analysis results is also presented and assessed.

FILTER FOR HIGH VELOCITY GAS STREAMS

DOEpatents

Heckman, R.A.; Warner, H.F.

1963-11-01

An air filter that is particularly useful in air-sampling rockets is presented. The filter comprises a cellulose fiber mat having an evenly disposed thin coating of stearic acid. Protective loose weave fabric covers are stitched to the front and back of the fiber mat, the stitching being in the form of a sine wave spiraled from the midpoint of the mat out to its periphery. (AEC)

Comparison of the compressive strengths for stitched and toughened composite systems

NASA Technical Reports Server (NTRS)

Reeder, James R.

1994-01-01

The compression strength of a stitched and a toughened matrix graphite/epoxy composite was determined and compared to a baseline unstitched untoughened composite. Two different layups with a variety of test lengths were tested under both ambient and hot/wet conditions. No significant difference in strength was seen for the different materials when the gage lengths of the specimens were long enough to lead to a buckling failure. For shorter specimens, a 30 percent reduction in strength from the baseline was seen due to stitching for both a 48-ply quasi-isotropic and a (0/45/0/-45/90/-45/0/45/0)s laminate. Analysis of the results suggested that the decrease in strength was due to increased fiber misalignment due to the stitches. An observed increasing strength with decreasing gage length, which was seen for all materials, was explained with a size effect model. The model assumed a random distribution of flaws (misaligned fibers). The toughened materials showed a small increase in strength over the baseline material for both laminates presumably due to the compensating effects of a more compliant matrix and straighter fibers in the toughened material. The hot/wet strength of the stitched and baseline material fell 30 percent below their ambient strengths for shorter, nonbuckling specimen, while the strength of the toughened matrix material only fell 20 percent. Video images of the failing specimen were recorded and showed local failures prior to global collapse of the specimen. These images support the theory of a random distribution of flaws controlling composite failure. Failed specimen appearance, however, seems to be a misleading indication of the cause of failure.

Test and analysis results for composite transport fuselage and wing structures

NASA Technical Reports Server (NTRS)

Deaton, Jerry W.; Kullerd, Susan M.; Madan, Ram C.; Chen, Victor L.

1992-01-01

Automated tow placement (ATP) and stitching of dry textile composite preforms followed by resin transfer molding (RTM) are being investigated by researchers at NASA LaRC and Douglas Aircraft Company as cost-effective manufacturing processes for obtaining damage tolerant fuselage and wing structures for transport aircraft. The Douglas work is being performed under a NASA contract entitled 'Innovative Composites Aircraft Primary Structures (ICAPS)'. Data are presented in this paper to assess the damage tolerance of ATP and RTM fuselage elements with stitched-on stiffeners from compression tests of impacted three-J-stiffened panels and from stiffener pull-off tests. Data are also presented to assess the damage tolerance of RTM wing elements which had stitched skin and stiffeners from impacted single stiffener and three blade-stiffened compression tests and stiffener pull-off tests.

[Shoes stitched, workers unstitched: a study on working and health conditions among women factory workers in the footwear industry in Franca, São Paulo State, Brazil].

PubMed

Prazeres, Taísa Junqueira; Navarro, Vera Lucia

2011-10-01

This study aimed to analyze associations between working conditions and health problems reported by women workers assigned to mechanical stitching in the footwear industry in Franca, São Paulo State, Brazil. The qualitative study's theory and methodology were based on historical and dialectical materialism and combined sociological and ethnographic research techniques. Data were collected with taped interviews, focusing on the workers' life and work stories, systematic observation of the work process, consultation of historical documents, and imagistic production. Analysis of the data revealed the effects of work in mechanical stitching on the health of women workers employed in the factory and at home, who experience precarious labor conditions involving workday intensification and extension, preset production targets, job insecurity, and unhealthy workplaces.

Acellular Flowable Matrix in the Treatment of Tunneled or Cavity Ulcers in Diabetic Feet: A Preliminary Report.

PubMed

Campitiello, Ferdinando; Mancone, Manfredi; Della Corte, Angela; Guerniero, Raffaella; Canonico, Silvestro

2018-06-01

The authors aimed to explore the feasibility and safety of an advanced, acellular, flowable wound matrix (FWM) in patients with diabetes-related cavity or tunnel lesions involving deep structures. Patients with diabetic foot ulcers were hospitalized at the General and Geriatric Surgery Unit of the University of Campania in Naples, Italy, between March 2015 and December 2015. Twenty-three patients with tunneled or cavity ulcers were treated. The lesions were filled with the FWM. Surgical wound edges were either approximated with stitches or left to heal by secondary intention. After 6 weeks, 78.26% of patients completely healed after a single application of the FWM. The healing time for all healed wounds was 30.85 ± 12.62 days, or 26.11 ± 5.43 days in patients for whom wound edges were approximated by stitches, and 57.66 ± 3.05 days in the patients who healed by secondary intention (P = .01). Permanent tissue regeneration was observed in a high percentage of patients, and shorter healing time was achieved. Study authors observed a low rate of complications such as major amputation and increased hospitalization. The FWM seems ideal for tunneled and cavity ulcers with irregular geometry. This new porous matrix allows closure of the lesion while reducing healing time and demolition surgery.

Novel percutaneous suture-mediated patent foramen ovale closure technique. Early results of the NobleStitch EL Italian Registry.

PubMed

Gaspardone, Achille; De Marco, Federico; Sgueglia, Gregory A; De Santis, Antonella; Iamele, Maria; D'Ascoli, Emanuela; Tusa, Maurizio; Corciu, Anca; Mullen, Michael; Nobles, Anthony; Carminati, Mario; Bedogni, Francesco

2018-04-03

To assess the efficacy of a novel percutaneous "device-less" suture mediated patent foramen ovale (PFO) closure system. Between June 2016 and October 2017, a prospective registry aimed at assessing the safety and efficacy of the NobleStitch EL (HeartStitch, Fountain Valley, CA) suture-based PFO closure system was carried out at 12 sites in Italy. Among 200 consecutive evaluated patients, 192 were considered suitable for suture-mediated PFO closure (44±13 years, 114 women). Suture of the septum with the NobleStitch EL system was carried out successfully in 186 (96%) patients. Median fluoroscopy time was 16.1 (13.0-22.5) minutes and contrast volume 200 (150-270) ml. At 206±130 days follow-up, microbubbles transthoracic echocardiography with Valsalva maneuver revealed no RLS (grade 0) in 139 (75%) patients and RLS grade ≤1 in 166 (89%) patients. Significant RLS was present in 20 (11%) patients (grade 2 and 3 in 11 and 9 patients, respectively). There were no device-related complications. The early results of this first Italian Registry indicates that the suture mediated "deviceless" closure of PFO is feasible in the majority of septal anatomies, provides an effective closure of PFO comparable to traditional devices with an excellent safety profile at medium term follow-up.

The Effects of Surface Waviness and of Rib Stitching on Wing Drag

NASA Technical Reports Server (NTRS)

Hood, Manley J

1939-01-01

Surface waviness and rib stitching have been investigated as part of a series of tests to determine the effects on wing drag of common surface irregularities. The tests were made in the N.A.C.A. 8-foot high-speed wind tunnel at Reynolds Numbers up to 17,000,000. The results of the tests showed that the waviness common to airplane wings will cause no serious increase in drag unless the waviness exists on the forward part of the wing, where it may cause premature transition or premature compressibility effects. Waves 3 inches wide and 0.048 inch high, for example, increased the drag 1 percent when they covered the rear 67 percent of both surfaces and 10 percent when they covered the rear 92 percent. A single wave 3 inches wide and only 0.020 inch high at the 10.5-percent-chord point on the upper surface caused transition to occur on the wave and increased the drag 6 percent. Rib stitching increased the drag 7 percent when the rib spacing was 6 inches; the drag increment was proportional to the number of ribs for wider spacings. About one-third of the increase was due to premature transition at the forward ends of the stitching.

Pressure Testing of a Minimum Gauge PRSEUS Panel

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew J.; Rouse, Marshall; Linton, Kim A.; Li, Victor P.

2011-01-01

Advanced aircraft configurations that have been developed to increase fuel efficiency require advanced, novel structural concepts capable of handling the unique load conditions that arise. One such concept is the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) developed by the Boeing Company. The PRSEUS concept is being investigated by NASA s Environmentally Responsible Aviation (ERA) Program for use in a hybrid-wing body (HWB) aircraft. This paper summarizes the analysis and test of a PRSEUS panel subjected to internal pressure, the first such pressure test for this structural concept. The pressure panel used minimum gauge skin, with stringer and frame configurations consistent with previous PRSEUS tests. Analysis indicated that for the minimum gauge skin panel, the stringer locations exhibit fairly linear response, but the skin bays between the stringers exhibit nonlinear response. Excellent agreement was seen between nonlinear analysis and test results in the critical portion at the center of the panel. The pristine panel was capable of withstanding the required 18.4 psi pressure load condition without exhibiting any damage. The impacted panel was capable of withstanding a pressure load in excess of 28 psi before initial failure occurred at the center stringer, and the panel was capable of sustaining increased pressure load after the initial failure. This successful PRSEUS panel pressure panel test was a critical step in the building block approach for enabling the use of this advanced structural concept on future aircraft, such as the HWB.

Analysis and Testing of a Metallic Repair Applicable to Pressurized Composite Aircraft Structure

NASA Technical Reports Server (NTRS)

Przekop, Adam; Jegley, Dawn C.; Rouse, Marshall; Lovejoy, Andrew E.

2014-01-01

Development of repair technology is vital to the long-term application of new structural concepts on aircraft structure. The design, analysis, and testing of a repair concept applicable to a stiffened composite panel based on the Pultruded Rod Stitched Efficient Unitized Structure was recently completed. The damage scenario considered was a mid-bay to mid-bay saw-cut with a severed stiffener, flange, and skin. A bolted metallic repair was selected so that it could be easily applied in the operational environment. The present work describes results obtained from tension and pressure panel tests conducted to validate both the repair concept and finite element analysis techniques used in the design effort. Simulation and experimental strain and displacement results show good correlation, indicating that the finite element modeling techniques applied in the effort are an appropriate compromise between required fidelity and computational effort. Static tests under tension and pressure loadings proved that the proposed repair concept is capable of sustaining load levels that are higher than those resulting from the current working stress allowables. Furthermore, the pressure repair panel was subjected to 55,000 pressure load cycles to verify that the design can withstand a life cycle representative for a transport category aircraft. These findings enable upward revision of the stress allowables that had been kept at an overly-conservative level due to concerns associated with repairability of the panels. This conclusion enables more weight efficient structural designs utilizing the composite concept under investigation.

Design Optimization and Characterization of Helicoidal Composites with Enhanced Impact Resistance

DTIC Science & Technology

2011-01-12

mitigating the delamination problem. The reinforcement can be achieved by many methods such as stitching, braiding , z-fibers/z-rods, fiber waviness or...that act perpendicular to the plane of the laminate. Some of these methods involve stitching, braiding , or weaving fibers together. Other methods use...temperature channels in the autoclave and attaching vacuum connector to the vacuum hose for inspecting the sealing system. For curing the composite, the

[The Misgav Ladach method for cesarean section].

PubMed

Habek, Dubravko; Kulas, Tomislav; Karsa, Matija

2007-04-01

The Misgav Ladach method for cesarean section is based on the principles of surgical minimalism. This is based on the Joel Cohen laparotomy, somewhat higher than the Pfannenstiel incision. Subcutaneous tissue is left undisturbed apart from the midline, rectus muscles are separated by pulling. The peritoneum is opened by stretching with index fingers. The hysterotomy is closed with one layer extraendometrial continuous absorbable stitches (Vicryl), and the visceral and parietal peritoneal layers are left open. Fascia is stitched with a continuous synthetic absorbable stitch. The skin is closed with intracutaneous resorptive suture or metallic stapler sutures. The Misgav Ladach method is restrictive in the use of sharp instruments preferring manual manipulation: it gives faster recovery, shorter period to normal bowel function, less peritoneal adhesions and less scarring in the abdominal layers, less use of postoperative antibiotics, analgesics and antipyretics, and a shorter anesthetic and operative time. It is ideal for emergency and planned cesarean section.

[Wound rupture after Misgav-Ladach cesarean section: a case report].

PubMed

Scholz, H S; Petru, E; Tamussino, K; Winter, R

2004-10-01

We describe a patient with wound rupture and burst abdomen after cesarean section with the Misgav-Ladach technique. A 33-year-old woman underwent primary cesarean section at 36 + 5 weeks gestation for a fetal indication. The procedure was done according to the Misgav-Ladach technique, i.e. the uterus was closed with a one-layer continuous locking stitch and the visceral and parietal peritoneal layers were left open. The rectus sheath was stitched with a continuous nonlocking stitch, the skin was closed with a continuous intracutaneous suture. On the seventh postoperative day, omentum was seen extruding from the skin incision. Reexploration showed that the suture of the rectus sheath had ruptured. The further postoperative course was uneventful. Although no general recommendations can be deduced from a single case, further reports on any complications of this technique will show whether it is as safe as believed until now.

Seamless image stitching by homography refinement and structure deformation using optimal seam pair detection

NASA Astrophysics Data System (ADS)

Lee, Daeho; Lee, Seohyung

2017-11-01

We propose an image stitching method that can remove ghost effects and realign the structure misalignments that occur in common image stitching methods. To reduce the artifacts caused by different parallaxes, an optimal seam pair is selected by comparing the cross correlations from multiple seams detected by variable cost weights. Along the optimal seam pair, a histogram of oriented gradients is calculated, and feature points for matching are detected. The homography is refined using the matching points, and the remaining misalignment is eliminated using the propagation of deformation vectors calculated from matching points. In multiband blending, the overlapping regions are determined from a distance between the matching points to remove overlapping artifacts. The experimental results show that the proposed method more robustly eliminates misalignments and overlapping artifacts than the existing method that uses single seam detection and gradient features.

Remote sensing image stitch using modified structure deformation

NASA Astrophysics Data System (ADS)

Pan, Ke-cheng; Chen, Jin-wei; Chen, Yueting; Feng, Huajun

2012-10-01

To stitch remote sensing images seamlessly without producing visual artifact which is caused by severe intensity discrepancy and structure misalignment, we modify the original structure deformation based stitching algorithm which have two main problems: Firstly, using Poisson equation to propagate deformation vectors leads to the change of the topological relationship between the key points and their surrounding pixels, which may bring in wrong image characteristics. Secondly, the diffusion area of the sparse matrix is too limited to rectify the global intensity discrepancy. To solve the first problem, we adopt Spring-Mass model and bring in external force to keep the topological relationship between key points and their surrounding pixels. We also apply tensor voting algorithm to achieve the global intensity corresponding curve of the two images to solve the second problem. Both simulated and experimental results show that our algorithm is faster and can reach better result than the original algorithm.

Impact testing of textile composite materials

NASA Technical Reports Server (NTRS)

Portanova, Marc

1995-01-01

The objectives of this report were to evaluate the impact damage resistance and damage tolerance of a variety of textile composite materials. Static indentation and impact tests were performed on the stitched and unstitched uniweave composites constructed from AS4/3501-6 Carbon/Epoxy with a fiberglass yarn woven in to hold the fibers together while being stitched. Compression and tension were measured after the tests to determine the damage resistance, residual strength and the damage tolerance of the specimens.

The Misgav Ladach method for cesarean section: method description.

PubMed

Holmgren, G; Sjöholm, L; Stark, M

1999-08-01

A method description is given for the Misgav Ladach method for cesarean section. This is based on the Joel-Cohen incision originally introduced for hysterectomy. The incision is a straight transverse incision somewhat higher than the Pfannenstiel incision. The subcutaneous tissue is left undisturbed apart from the midline. The rectus sheath is separated along its fibres. The rectus muscles are separated by pulling. The peritoneum is opened by stretching with index fingers. The uterus is opened with an index finger and the hole enlarged between the index finger of one hand and the thumb on the other. The uterus is closed with a one-layer continuous locking stitch. The visceral and parietal peritoneal layers are left open. The rectus muscle is not stitched. The rectus sheath is stitched with a continuous non-locking stitch. The skin is closed with two or three mattress sutures. The space in between is apposed with non-traumatic forceps for 5 minutes. The basic philosophy is to work in harmony with the body's anatomy and physiology and not against them. The method is restrictive in the use of sharp instruments, preferring manual manipulation. The method gives quicker recovery, less use of post-operative antibiotics, antifebrile medicines and analgesics. There is a shorter anesthetic and shorter working time for the operative team. It is suitable for both emergency and planned operations.

Effects of eliminating tension by means of epineural stitches: a comparative electrophysiological and histomorphometrical study using different suture techniques in an animal model.

PubMed

Bustamante, Jorge; Socolovsky, Mariano; Martins, Roberto S; Emmerich, Juan; Pennini, Maria Gabriela; Lausada, Natalia; Domitrovic, Luis

2011-01-01

Epineural stitches are a means to avoid tension in a nerve suture. We evaluate this technique, relative to interposed grafts and simple neurorraphy, in a rat model. Twenty rats were allocated to four groups. For Group 1, sectioning of the sciatic nerve was performed, a segment 4 mm long discarded, and epineural suture with distal anchoring stitches were placed resulting in slight tension neurorraphy. For Group 2, a simple neurorraphy was performed. For Group 3, a 4 mm long graft was employed and Group 4 served as control. Ninety days after, reoperation, latency of motor action potentials recording and axonal counts were performed. Inter-group comparison was done by means of ANOVA and the non-parametric Kruskal-Wallis test. The mean motor latency for the simple suture (2.27±0.77 ms) was lower than for the other two surgical groups, but lower than among controls (1.69±0.56 ms). Similar values were founding in both group 1 (2.66±0.71 ms) and group 3 (2.64±0.6 ms). When fibers diameters were compared a significant difference was identified between groups 2 and 3 (p=0.048). Good results can be obtained when suturing a nerve employ with epineural anchoring stitches. However, more studies are needed before extrapolating results to human nerve sutures.

Efficient preparation of graphene liquid cell utilizing direct transfer with large-area well-stitched graphene

NASA Astrophysics Data System (ADS)

Sasaki, Yuki; Kitaura, Ryo; Yuk, Jong Min; Zettl, Alex; Shinohara, Hisanori

2016-04-01

By utilizing graphene-sandwiched structures recently developed in this laboratory, we are able to visualize small droplets of liquids in nanometer scale. We have found that small water droplets as small as several tens of nanometers sandwiched by two single-layer graphene are frequently observed by TEM. Due to the electron beam irradiation during the TEM observation, these sandwiched droplets are frequently moving from one place to another and are subjected to create small bubbles inside. The synthesis of a large area single-domain graphene of high-quality is essential to prepare the graphene sandwiched cell which safely encapsulates the droplets in nanometer size.

Detrended Fluctuation Analysis and Adaptive Fractal Analysis of Stride Time Data in Parkinson's Disease: Stitching Together Short Gait Trials

PubMed Central

Liebherr, Magnus; Haas, Christian T.

2014-01-01

Variability indicates motor control disturbances and is suitable to identify gait pathologies. It can be quantified by linear parameters (amplitude estimators) and more sophisticated nonlinear methods (structural information). Detrended Fluctuation Analysis (DFA) is one method to measure structural information, e.g., from stride time series. Recently, an improved method, Adaptive Fractal Analysis (AFA), has been proposed. This method has not been applied to gait data before. Fractal scaling methods (FS) require long stride-to-stride data to obtain valid results. However, in clinical studies, it is not usual to measure a large number of strides (e.g., strides). Amongst others, clinical gait analysis is limited due to short walkways, thus, FS seem to be inapplicable. The purpose of the present study was to evaluate FS under clinical conditions. Stride time data of five self-paced walking trials ( strides each) of subjects with PD and a healthy control group (CG) was measured. To generate longer time series, stride time sequences were stitched together. The coefficient of variation (CV), fractal scaling exponents (DFA) and (AFA) were calculated. Two surrogate tests were performed: A) the whole time series was randomly shuffled; B) the single trials were randomly shuffled separately and afterwards stitched together. CV did not discriminate between PD and CG. However, significant differences between PD and CG were found concerning and . Surrogate version B yielded a higher mean squared error and empirical quantiles than version A. Hence, we conclude that the stitching procedure creates an artificial structure resulting in an overestimation of true . The method of stitching together sections of gait seems to be appropriate in order to distinguish between PD and CG with FS. It provides an approach to integrate FS as standard in clinical gait analysis and to overcome limitations such as short walkways. PMID:24465708

KSC-04pd0624

NASA Image and Video Library

2004-03-25

KENNEDY SPACE CENTER, FLA. -- Damon Petty, with United Space Alliance, removes a piece of insulation blanket from an “oven” after heat cleaning. The blankets fit inside the nose cap of an orbiter. They consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches.

KSC-04pd0626

NASA Image and Video Library

2004-03-25

KENNEDY SPACE CENTER, FLA. -- Damon Petty, with United Space Alliance, covers another insulation blanket in the “oven” prior to heat cleaning. The blankets fit inside the nose cap of an orbiter. They consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches.

KSC-04pd0623

NASA Image and Video Library

2004-03-25

KENNEDY SPACE CENTER, FLA. -- Damon Petty, with United Space Alliance, places pieces of insulation blanket into an “oven” for heat cleaning. The blankets fit inside the nose cap of an orbiter. They consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches.

KSC-04pd0628

NASA Image and Video Library

2004-03-25

KENNEDY SPACE CENTER, FLA. -- Damon Petty, with United Space Alliance, gets ready to place insulation blankets on the shelf after they have been heated. The blankets fit inside the nose cap of an orbiter. They consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches.

KSC-04pd0625

NASA Image and Video Library

2004-03-25

KENNEDY SPACE CENTER, FLA. -- Damon Petty, with United Space Alliance, removes another insulation blanket from a shelf prior to heat cleaning and waterproofing. The blankets fit inside the nose cap of an orbiter. They consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches.

KSC-04pd0627

NASA Image and Video Library

2004-03-25

KENNEDY SPACE CENTER, FLA. -- Damon Petty, with United Space Alliance, prepares the cover of another insulation blanket in the “oven” prior to heat cleaning. The blankets fit inside the nose cap of an orbiter. They consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches.

KSC-04pd0622

NASA Image and Video Library

2004-03-25

KENNEDY SPACE CENTER, FLA. -- Damon Petty, with United Space Alliance, removes an insulation blanket from a shelf prior to heat cleaning and waterproofing. The blankets fit inside the nose cap of an orbiter. They consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches.

Low cost damage tolerant composite fabrication

NASA Technical Reports Server (NTRS)

Palmer, R. J.; Freeman, W. T.

1988-01-01

The resin transfer molding (RTM) process applied to composite aircraft parts offers the potential for using low cost resin systems with dry graphite fabrics that can be significantly less expensive than prepreg tape fabricated components. Stitched graphite fabric composites have demonstrated compression after impact failure performance that equals or exceeds that of thermoplastic or tough thermoset matrix composites. This paper reviews methods developed to fabricate complex shape composite parts using stitched graphite fabrics to increase damage tolerance with RTM processes to reduce fabrication cost.

Structural Integrity Testing Method for PRSEUS Rod-Wrap Stringer Design

NASA Technical Reports Server (NTRS)

Wang, John T.; Grenoble, Ray W.; Pickell, Robert D.

2012-01-01

NASA Langley Research Center and The Boeing Company are developing an innovative composite structural concept, called PRSEUS, for the flat center section of a future environmentally friendly hybrid wing body (HWB) aircraft. The PRSEUS (Pultruded Rod Stitched Efficient Unitized Structure) concept uses dry textile preforms for the skins, frames, and stiffener webs. The highly loaded stiffeners are made from precured unidirectional carbon/epoxy rods and dry fiber preforms. The rods are wrapped with the dry fiber preforms and a resin infusion process is used to form the rod-wrap stiffeners. The structural integrity of the rod-wrap interface is critical for maintaining the panel s high strength and bending rigidity. No standard testing method exists for testing the strength of the rod-wrap bondline. Recently, Boeing proposed a rod push-out testing method and conducted some preliminary tests using this method. This paper details an analytical study of the rod-wrap bondline. The rod-wrap interface is modeled as a cohesive zone for studying the initiation and growth of interfacial debonding during push-out testing. Based on the correlations of analysis results and Boeing s test data, the adequacy of the rod-wrap testing method is evaluated, and potential approaches for improvement of the test method are proposed.

Analysis of a Hybrid Wing Body Center Section Test Article

NASA Technical Reports Server (NTRS)

Wu, Hsi-Yung T.; Shaw, Peter; Przekop, Adam

2013-01-01

The hybrid wing body center section test article is an all-composite structure made of crown, floor, keel, bulkhead, and rib panels utilizing the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) design concept. The primary goal of this test article is to prove that PRSEUS components are capable of carrying combined loads that are representative of a hybrid wing body pressure cabin design regime. This paper summarizes the analytical approach, analysis results, and failure predictions of the test article. A global finite element model of composite panels, metallic fittings, mechanical fasteners, and the Combined Loads Test System (COLTS) test fixture was used to conduct linear structural strength and stability analyses to validate the specimen under the most critical combination of bending and pressure loading conditions found in the hybrid wing body pressure cabin. Local detail analyses were also performed at locations with high stress concentrations, at Tee-cap noodle interfaces with surrounding laminates, and at fastener locations with high bearing/bypass loads. Failure predictions for different composite and metallic failure modes were made, and nonlinear analyses were also performed to study the structural response of the test article under combined bending and pressure loading. This large-scale specimen test will be conducted at the COLTS facility at the NASA Langley Research Center.

Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure. Part 1; Ultimate Design Loads

NASA Technical Reports Server (NTRS)

Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.

2016-01-01

The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses finite element analysis and testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part I of the paper considers the five most critical load conditions, which are internal pressure only and positive and negative g-loads with and without internal pressure. Analysis results are compared with measurements acquired during testing. Performance of the test article is found to be closely aligned with predictions and, consequently, able to support the hybrid wing body design loads in pristine and barely visible impact damage conditions.

Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure . Part II; Severe Damage

NASA Technical Reports Server (NTRS)

Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.

2016-01-01

The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a finite element analysis and the testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part II of the paper considers the final test to failure of the test article in the presence of an intentionally inflicted severe discrete source damage under the wing up-bending loading condition. Finite element analysis results are compared with measurements acquired during the test and demonstrate that the hybrid wing body test article was able to redistribute and support the required design loads in a severely damaged condition.

Preliminary Design and Analysis of an In-plane PRSEUS Joint

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.; Poplawski, Steven

2013-01-01

As part of the National Aeronautics and Space Administration's (NASA's) Environmentally Responsible Aviation (ERA) program, the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) has been designed, developed and tested. However, PRSEUS development efforts to date have only addressed joints required to transfer bending moments between PRSEUS panels. Development of in-plane joints for the PRSEUS concept is necessary to facilitate in-plane transfer of load from PRSEUS panels to an adjacent structure, such as from a wing panel into a fuselage. This paper presents preliminary design and analysis of an in-plane PRSEUS joint for connecting PRSEUS panels at the termination of the rod-stiffened stringers. Design requirements are provided, the PRSEUS blade joint concept is presented, and preliminary design changes and analyses are carried out to examine the feasibility of the proposed in-plane PRSEUS blade joint. The study conducted herein focuses mainly on the PRSEUS structure on one side of the joint. In particular, the design requirements for the rod shear stress and bolt bearing stress are examined. A PRSEUS blade joint design was developed that demonstrates the feasibility of this in-plane PRSEUS joint concept to terminate the rod-stiffened stringers. The presented design only demonstrates feasibility, therefore, some areas of refinement are presented that would lead to a more optimum and realistic design.

Parallax handling of image stitching using dominant-plane homography

NASA Astrophysics Data System (ADS)

Pang, Zhaofeng; Li, Cheng; Zhao, Baojun; Tang, Linbo

2015-10-01

In this paper, we present a novel image stitching method to handle parallax in practical application. For images with significant amount of parallax, the more effective approach is to align roughly and globally the overlapping regions and then apply a seam-cutting method to composite naturally stitched images. It is well known that images can be modeled by various planes result from the projective parallax under non-ideal imaging condition. The dominant-plane homography has important advantages of warping an image globally and avoiding some local distortions. The proposed method primarily addresses large parallax problem through two steps: (1) selecting matching point pairs located on the dominant plane, by clustering matching correspondences and then measuring the cost of each cluster; and (2) in order to obtain a plausible seam, edge maps of overlapped area incorporation arithmetic is adopted to modify the standard seam-cutting method. Furthermore, our approach is demonstrated to achieve reliable performance of handling parallax through a mass of experimental comparisons with state-of-the-art methods.

Influence of Tow Architecture on Compaction and Nesting in Textile Preforms

NASA Astrophysics Data System (ADS)

Yousaf, Z.; Potluri, P.; Withers, P. J.

2017-04-01

Transverse compression response of tows during processes such as vacuum infusion or autoclave curing has significant influence on resin permeability in fabrics as well as the laminate thickness, fibre volume fraction and tow orientations in the finished composite. This paper reports macro -scale deformations in dry fibre assemblies due to transverse compaction. In this study, influence of weave geometry and the presence of interlacements or stitches on the ply-level compaction as well as nesting have been investigated. 2D woven fabrics with a variety of interlacement patterns - plain, twill and sateen- as well as stitched Non-crimp (NCF) fabrics have been investigated for macro-level deformations. Compression response of single layer and multilayer stacks has been studied as a function of external pressure in order to establish nesting behaviour. It appears that the degree of individual ply compaction and degree of nesting between the plies are influenced by tow architectures. Inter-tow spacing and stitching thread thickness appears to influence the degree of nesting in non-crimp fabrics.

Stitching Type Large Aperture Depolarizer for Gas Monitoring Imaging Spectrometer

NASA Astrophysics Data System (ADS)

Liu, X.; Li, M.; An, N.; Zhang, T.; Cao, G.; Cheng, S.

2018-04-01

To increase the accuracy of radiation measurement for gas monitoring imaging spectrometer, it is necessary to achieve high levels of depolarization of the incoming beam. The preferred method in space instrument is to introduce the depolarizer into the optical system. It is a combination device of birefringence crystal wedges. Limited to the actual diameter of the crystal, the traditional depolarizer cannot be used in the large aperture imaging spectrometer (greater than 100 mm). In this paper, a stitching type depolarizer is presented. The design theory and numerical calculation model for dual babinet depolarizer were built. As required radiometric accuracies of the imaging spectrometer with 250 mm × 46 mm aperture, a stitching type dual babinet depolarizer was design in detail. Based on designing the optimum structural parmeters the tolerance of wedge angle refractive index, and central thickness were given. The analysis results show that the maximum residual polarization degree of output light from depolarizer is less than 2 %. The design requirements of polarization sensitivity is satisfied.

Image stitching and image reconstruction of intestines captured using radial imaging capsule endoscope

NASA Astrophysics Data System (ADS)

Ou-Yang, Mang; Jeng, Wei-De; Wu, Yin-Yi; Dung, Lan-Rong; Wu, Hsien-Ming; Weng, Ping-Kuo; Huang, Ker-Jer; Chiu, Luan-Jiau

2012-05-01

This study investigates image processing using the radial imaging capsule endoscope (RICE) system. First, an experimental environment is established in which a simulated object has a shape that is similar to a cylinder, such that a triaxial platform can be used to push the RICE into the sample and capture radial images. Then four algorithms (mean absolute error, mean square error, Pearson correlation coefficient, and deformation processing) are used to stitch the images together. The Pearson correlation coefficient method is the most effective algorithm because it yields the highest peak signal-to-noise ratio, higher than 80.69 compared to the original image. Furthermore, a living animal experiment is carried out. Finally, the Pearson correlation coefficient method and vector deformation processing are used to stitch the images that were captured in the living animal experiment. This method is very attractive because unlike the other methods, in which two lenses are required to reconstruct the geometrical image, RICE uses only one lens and one mirror.

A transition to laparoendoscopic single-site surgery (LESS) radical prostatectomy: human cadaver experimental and initial clinical experience.

PubMed

Barret, Eric; Sanchez-Salas, Rafael; Kasraeian, Ali; Benoist, Nicolas; Ganatra, Anjali; Cathelineau, Xavier; Rozet, Francois; Galiano, Marc; Vallancien, Guy

2009-01-01

Laparoendoscopic single-site surgery (LESS) represents a novel approach to abdominal surgery. Several applications have already been described. Drawbacks include limited range of motion and need for articulated instruments. Robotic technology could overcome such technical difficulties. We report our experience with LESS radical prostatectomy (LESS-RP) in a cadaver and LESS robot-assisted radical prostatectomy (LESS-RARP) in a human patient. Standard laparoscopic instruments (SLI) and articulated laparoscopic instruments were used in the cadaveric LESS-RP. The da Vinci system was used in the LESS-RARP. Both procedures reproduced standard extraperitoneal laparoscopic prostatectomy as performed at Institut Montsouris. Control of the dorsal venous complex (DVC) and urethrovesical anastomosis (UVA) were key elements evaluated for feasibility. Cadaveric model: Total operative time (TOT) was 160 minutes, with 5 minutes for the DVC (one stitch) and 35 minutes for the UVA (six stitches). Although articulated instruments were helpful in the operation, SLI remained essential for the procedure. Clinical experience: LESS-RARP was performed for T(1c) prostate cancer. TOT was 150 minutes, including 5 minutes for the DVC (one figure-of-eight stitch) and 30 minutes for the UVA (six interrupted stitches). Blood loss was 500 mL. Bilateral neurovascular preservation was performed, and results of final pathologic examination showed negative surgical margins. The human cadaver is an adequate model for LESS-RP, and LESS-RARP is feasible to be performed in the clinical arena. The synergy of robotic technology and LESS represents a new generation of surgery.

The objective assessment of experts' and novices' suturing skills using an image analysis program.

PubMed

Frischknecht, Adam C; Kasten, Steven J; Hamstra, Stanley J; Perkins, Noel C; Gillespie, R Brent; Armstrong, Thomas J; Minter, Rebecca M

2013-02-01

To objectively assess suturing performance using an image analysis program and to provide validity evidence for this assessment method by comparing experts' and novices' performance. In 2009, the authors used an image analysis program to extract objective variables from digital images of suturing end products obtained during a previous study involving third-year medical students (novices) and surgical faculty and residents (experts). Variables included number of stitches, stitch length, total bite size, travel, stitch orientation, total bite-size-to-travel ratio, and symmetry across the incision ratio. The authors compared all variables between groups to detect significant differences and two variables (total bite-size-to-travel ratio and symmetry across the incision ratio) to ideal values. Five experts and 15 novices participated. Experts' and novices' performances differed significantly (P < .05) with large effect sizes attributable to experience (Cohen d > 0.8) for total bite size (P = .009, d = 1.5), travel (P = .045, d = 1.1), total bite-size-to-travel ratio (P < .0001, d = 2.6), stitch orientation (P = .014,d = 1.4), and symmetry across the incision ratio (P = .022, d = 1.3). The authors found that a simple computer algorithm can extract variables from digital images of a running suture and rapidly provide quantitative summative assessment feedback. The significant differences found between groups confirm that this system can discriminate between skill levels. This image analysis program represents a viable training tool for objectively assessing trainees' suturing, a foundational skill for many medical specialties.

Recent developments using TowerJazz SiGe BiCMOS platform for mmWave and THz applications

NASA Astrophysics Data System (ADS)

Kar-Roy, Arjun; Howard, David; Preisler, Edward J.; Racanelli, Marco

2013-05-01

In this paper, we report on the highest speed 240GHz/340GHz FT/FMAX NPN which is now available for product designs in the SBC18H4 process variant of TowerJazz's mature 0.18μm SBC18 silicon germanium (SiGe) BiCMOS technology platform. NFMIN of ~2dB at 50GHz has been obtained with these NPNs. We also describe the integration of earlier generation NPNs with FT/FMAX of 240GHz/280GHz into SBC13H3, a 0.13μm SiGe BiCMOS technology platform. Next, we detail the integration of the deep silicon via (DSV), through silicon via (TSV), high-resistivity substrate, sub-field stitching and hybrid-stitching capability into the 0.18μm SBC18 technology platform to enable higher performance and highly integrated product designs. The integration of SBC18H3 into a thick-film SOI substrate, with essentially unchanged FT and FMAX, is also described. We also report on recent circuit demonstrations using the SBC18H3 platform: (1) a 4-element phased-array 70-100GHz broadband transmit and receive chip with flat saturated power greater than 5dBm and conversion gain of 33dB; (2) a fully integrated W-band 9-element phase-controllable array with responsivity of 800MV/W and receiver NETD is 0.45K with 20ms integration time; (3) a 16-element 4x4 phased-array transmitter with scanning in both the E- and H-planes with maximum EIRP of 23-25 dBm at 100-110GHz; (4) a power efficient 200GHz VCO with -7.25dBm output power and tuning range of 3.5%; and (5) a 320GHz 16-element imaging receiver array with responsivity of 18KV/W at 315GHz, a 3dB bandwidth of 25GHz and a low NEP of 34pW/Hz1/2. Wafer-scale large-die implementation of the phased-arrays and mmWave imagers using stitching in TowerJazz SBC18 process are also discussed.

American Needlepoint Guild

NASA Technical Reports Server (NTRS)

2000-01-01

The Apollo-Soyuz mission patch stitched by Pat Correz of Rialto, Calif., a member of the American Needlepoint Guild, was one of the 123 hand-stitched needlepoint patches donated to NASA's Stennis Space Center in Hancock County, Miss. The colorful, intricately detailed patches, commemorating American human space flight mission flown to date, were the project of individual needlepoint stitchers, ranging in age from 29 to 89 from across the country who are members of the non-profit guild. The exhibit is located at the entrance to Millennium Hall in the space center's visitor center, StenniSphere.

Analysis to feature-based video stabilization/registration techniques within application of traffic data collection

NASA Astrophysics Data System (ADS)

Sadat, Mojtaba T.; Viti, Francesco

2015-02-01

Machine vision is rapidly gaining popularity in the field of Intelligent Transportation Systems. In particular, advantages are foreseen by the exploitation of Aerial Vehicles (AV) in delivering a superior view on traffic phenomena. However, vibration on AVs makes it difficult to extract moving objects on the ground. To partly overcome this issue, image stabilization/registration procedures are adopted to correct and stitch multiple frames taken of the same scene but from different positions, angles, or sensors. In this study, we examine the impact of multiple feature-based techniques for stabilization, and we show that SURF detector outperforms the others in terms of time efficiency and output similarity.

A novel approach to assess clinical competence of postgraduate year 1 surgery residents

PubMed Central

Qi, Xin; Ding, Lian; Zhai, Wei; Li, Qiang; Li, Yan; Li, Haichao; Wen, Bing

2017-01-01

ABSTRACT Background: An increased demand for accountability and transparency in medicine have initiated a shift toward a more objective and standardized approach for postgraduate medical training. Objective: To develop and evaluate an objective method to assess clinical competence of postgraduate year 1 surgery residents. Design: Thirty-one postgraduate year 1 surgery residents, who had been trained in the Surgical School of Peking University First Hospital for one year, participated in an objective structured clinical examination as a final assessment of their clinical competence. A test station of irregular wound repair (debridement and suture) was specially designed to test the residents’ surgical integrative competence in a complex-trauma treatment procedure. A modified global rating scale, in combination with wound area measurement, was applied to evaluate residents’ surgical performance. The validity of the subjective global rating scale was evaluated by the objective measurement results from the software. Results: The global rating scale score had no obvious correlation with the area of the removed tissue and the residual wound area after the suture. There was significant difference in the debridement time and the residual wound area between 0–3 and >3 total stitches. There were significant differences in the area of the removed tissue between 0 and 1–2 grey stitches and 0 and 3–4 grey stitches, and in the residual wound area after suture between 0 and 3–4 grey stitches and 1–2 and 3–4 grey stitches. Conclusions: An irregular wound repair procedure could be an effective method to assess the integrative competence of surgery residents. The training for surgical thinking in the early stage of junior residents needs to be strengthened. The entire measurement process was more complex and time-consuming than expected. The possibility of measurement by simply counting the numbers of the key spots might be explored in the future. Abbreviations: ACS/APDS American College of Surgeons/Association of Program Directors in Surgery; GRS Global rating scale; LSD-T Least significant difference-test; OSATS Objective structured assessment of technical skills; OSCE Objective structured clinical examination; PBT Proficiency based training; PGY1 Postgraduate Year 1 PMID:28670976

[Application of three-stitch preventive transverse colostomy in anterior resection of low rectal cancer].

PubMed

Zhao, Yuzhou; Han, Guangsen; Huo, Mingke; Wei, Li; Zou, Qiyun; Zhang, Yuji; Li, Jian; Gu, Yanhui; Cao, Yanghui; Zhang, Shijia

2017-04-25

To explore the application of three-stitch preventive transverse colostomy in anterior resection of low rectal cancer. From May 2015 to March 2016, 70 consecutive low rectal cancer patients undergoing anterior resection and preventive transverse colostomy in our department were recruited in this prospective study. According to the random number table method, 70 patients were divided into three-stitch transverse colostomy group(observation group, n=35) and traditional transverse colostomy group(control group, n=35). Procedure of three-stitch preventive transverse colostomy was as follows: firstly, at the upper 1/3 incision 0.5-1.0 cm distance from the skin, 7# silk was used to suture from outside to inside, then the needle belt line went through the transverse edge of the mesangial avascular zone. At the lower 1/3 incision 0.5-1.0 cm distance from the skin, 7# silk was used to suture from inside to outside, then silk went through the transverse edge of the mesangial avascular zone again and was ligatured. Finally, in the upper and lower ends of the stoma, 7# silk was used to suture and fix transverse seromuscular layer and the skin. The operation time and morbidity of postoperative complications associated with colostomy were compared between two groups. There were no significant differences in baseline data between the two groups(all P>0.05). The operative time of observation group was shorter than that of control group [(3.2±1.3) min vs. (15.5±3.4) min, P<0.05]. Incidences of colostomy skin-mucous separation, dermatitis, stoma rebound were significantly lower in observation group [5.7%(2/35) vs. 34.3%(12/35), P=0.007; 8.6%(3/35) vs. 31.4%(11/35), P=0.036; 0 vs. 17.1%(6/35), P=0.025, respectively], while incidences of parastomal hernia and stoma prolapse in two groups were similar (both P>0.05). Compared with traditional transverse colostomy method, the three-stitch preventive transverse colostomy has more operating advantages and can reduce postoperative complications associated with colostomy.

Automated Stitching of Microtubule Centerlines across Serial Electron Tomograms

PubMed Central

Weber, Britta; Tranfield, Erin M.; Höög, Johanna L.; Baum, Daniel; Antony, Claude; Hyman, Tony; Verbavatz, Jean-Marc; Prohaska, Steffen

2014-01-01

Tracing microtubule centerlines in serial section electron tomography requires microtubules to be stitched across sections, that is lines from different sections need to be aligned, endpoints need to be matched at section boundaries to establish a correspondence between neighboring sections, and corresponding lines need to be connected across multiple sections. We present computational methods for these tasks: 1) An initial alignment is computed using a distance compatibility graph. 2) A fine alignment is then computed with a probabilistic variant of the iterative closest points algorithm, which we extended to handle the orientation of lines by introducing a periodic random variable to the probabilistic formulation. 3) Endpoint correspondence is established by formulating a matching problem in terms of a Markov random field and computing the best matching with belief propagation. Belief propagation is not generally guaranteed to converge to a minimum. We show how convergence can be achieved, nonetheless, with minimal manual input. In addition to stitching microtubule centerlines, the correspondence is also applied to transform and merge the electron tomograms. We applied the proposed methods to samples from the mitotic spindle in C. elegans, the meiotic spindle in X. laevis, and sub-pellicular microtubule arrays in T. brucei. The methods were able to stitch microtubules across section boundaries in good agreement with experts' opinions for the spindle samples. Results, however, were not satisfactory for the microtubule arrays. For certain experiments, such as an analysis of the spindle, the proposed methods can replace manual expert tracing and thus enable the analysis of microtubules over long distances with reasonable manual effort. PMID:25438148

Capturing and stitching images with a large viewing angle and low distortion properties for upper gastrointestinal endoscopy

NASA Astrophysics Data System (ADS)

Liu, Ya-Cheng; Chung, Chien-Kai; Lai, Jyun-Yi; Chang, Han-Chao; Hsu, Feng-Yi

2013-06-01

Upper gastrointestinal endoscopies are primarily performed to observe the pathologies of the esophagus, stomach, and duodenum. However, when an endoscope is pushed into the esophagus or stomach by the physician, the organs behave similar to a balloon being gradually inflated. Consequently, their shapes and depth-of-field of images change continually, preventing thorough examination of the inflammation or anabrosis position, which delays the curing period. In this study, a 2.9-mm image-capturing module and a convoluted mechanism was incorporated into the tube like a standard 10- mm upper gastrointestinal endoscope. The scale-invariant feature transform (SIFT) algorithm was adopted to implement disease feature extraction on a koala doll. Following feature extraction, the smoothly varying affine stitching (SVAS) method was employed to resolve stitching distortion problems. Subsequently, the real-time splice software developed in this study was embedded in an upper gastrointestinal endoscope to obtain a panoramic view of stomach inflammation in the captured images. The results showed that the 2.9-mm image-capturing module can provide approximately 50 verified images in one spin cycle, a viewing angle of 120° can be attained, and less than 10% distortion can be achieved in each image. Therefore, these methods can solve the problems encountered when using a standard 10-mm upper gastrointestinal endoscope with a single camera, such as image distortion, and partial inflammation displays. The results also showed that the SIFT algorithm provides the highest correct matching rate, and the SVAS method can be employed to resolve the parallax problems caused by stitching together images of different flat surfaces.

Comparing the da Vinci si single console and dual console in teaching novice surgeons suturing techniques.

PubMed

Crusco, Salvatore; Jackson, Tiffany; Advincula, Arnold

2014-01-01

Robot-assisted laparoscopic surgery is often taught with the surgical mentor at the surgeon console and the trainee at the patient's bedside. The da Vinci dual console (Intuitive Surgical, Sunnyvale, California) allows a surgical mentor to teach with both the mentor and the trainee working at a surgeon console simultaneously. The purpose of this study is to evaluate the effectiveness of the dual console versus the single console for teaching medical students robotic tasks. Forty novice medical students were randomized to either the da Vinci single-console or dual-console group and were taught 4 knot-tying techniques by a surgical mentor. The students were timed while performing the tasks. No statistically significant differences in mean task times were observed between the single- and dual-console groups: interrupted stitch with a 2-handed knot (300 seconds for single vs 294 seconds for dual, P=.59), interrupted stitch with a 1-handed knot (198 seconds for single vs 212 seconds for dual, P=.88), figure-of-8 stitch with a 2-handed knot (261 seconds for single vs 219 seconds for dual, P=.20), and figure-of-8 stitch with a 1-handed knot (200 seconds for single vs 199 seconds for dual, P=.53). No significant difference was observed in performance time when teaching knot-tying techniques to medical students using the da Vinci dual console compared with the single console. More research needs to be performed on the utility of the da Vinci dual console in surgical training.

Comparing the da Vinci Si Single Console and Dual Console in Teaching Novice Surgeons Suturing Techniques

PubMed Central

Jackson, Tiffany; Advincula, Arnold

2014-01-01

Background and Objectives: Robot-assisted laparoscopic surgery is often taught with the surgical mentor at the surgeon console and the trainee at the patient's bedside. The da Vinci dual console (Intuitive Surgical, Sunnyvale, California) allows a surgical mentor to teach with both the mentor and the trainee working at a surgeon console simultaneously. The purpose of this study is to evaluate the effectiveness of the dual console versus the single console for teaching medical students robotic tasks. Methods: Forty novice medical students were randomized to either the da Vinci single-console or dual-console group and were taught 4 knot-tying techniques by a surgical mentor. The students were timed while performing the tasks. Results: No statistically significant differences in mean task times were observed between the single- and dual-console groups: interrupted stitch with a 2-handed knot (300 seconds for single vs 294 seconds for dual, P = .59), interrupted stitch with a 1-handed knot (198 seconds for single vs 212 seconds for dual, P = .88), figure-of-8 stitch with a 2-handed knot (261 seconds for single vs 219 seconds for dual, P = .20), and figure-of-8 stitch with a 1-handed knot (200 seconds for single vs 199 seconds for dual, P = .53). Conclusion: No significant difference was observed in performance time when teaching knot-tying techniques to medical students using the da Vinci dual console compared with the single console. More research needs to be performed on the utility of the da Vinci dual console in surgical training. PMID:25392618

Automated stitching of microtubule centerlines across serial electron tomograms.

PubMed

Weber, Britta; Tranfield, Erin M; Höög, Johanna L; Baum, Daniel; Antony, Claude; Hyman, Tony; Verbavatz, Jean-Marc; Prohaska, Steffen

2014-01-01

Tracing microtubule centerlines in serial section electron tomography requires microtubules to be stitched across sections, that is lines from different sections need to be aligned, endpoints need to be matched at section boundaries to establish a correspondence between neighboring sections, and corresponding lines need to be connected across multiple sections. We present computational methods for these tasks: 1) An initial alignment is computed using a distance compatibility graph. 2) A fine alignment is then computed with a probabilistic variant of the iterative closest points algorithm, which we extended to handle the orientation of lines by introducing a periodic random variable to the probabilistic formulation. 3) Endpoint correspondence is established by formulating a matching problem in terms of a Markov random field and computing the best matching with belief propagation. Belief propagation is not generally guaranteed to converge to a minimum. We show how convergence can be achieved, nonetheless, with minimal manual input. In addition to stitching microtubule centerlines, the correspondence is also applied to transform and merge the electron tomograms. We applied the proposed methods to samples from the mitotic spindle in C. elegans, the meiotic spindle in X. laevis, and sub-pellicular microtubule arrays in T. brucei. The methods were able to stitch microtubules across section boundaries in good agreement with experts' opinions for the spindle samples. Results, however, were not satisfactory for the microtubule arrays. For certain experiments, such as an analysis of the spindle, the proposed methods can replace manual expert tracing and thus enable the analysis of microtubules over long distances with reasonable manual effort.

Smart tissue anastomosis robot (STAR): a vision-guided robotics system for laparoscopic suturing.

PubMed

Leonard, Simon; Wu, Kyle L; Kim, Yonjae; Krieger, Axel; Kim, Peter C W

2014-04-01

This paper introduces the smart tissue anastomosis robot (STAR). Currently, the STAR is a proof-of-concept for a vision-guided robotic system featuring an actuated laparoscopic suturing tool capable of executing running sutures from image-based commands. The STAR tool is designed around a commercially available laparoscopic suturing tool that is attached to a custom-made motor stage and the STAR supervisory control architecture that enables a surgeon to select and track incisions and the placement of stitches. The STAR supervisory-control interface provides two modes: A manual mode that enables a surgeon to specify the placement of each stitch and an automatic mode that automatically computes equally-spaced stitches based on an incision contour. Our experiments on planar phantoms demonstrate that the STAR in either mode is more accurate, up to four times more consistent and five times faster than surgeons using state-of-the-art robotic surgical system, four times faster than surgeons using manual Endo360(°)®, and nine times faster than surgeons using manual laparoscopic tools.

Reduce volume of head-up display by image stitching

NASA Astrophysics Data System (ADS)

Chiu, Yi-Feng; Su, Guo-Dung J.

2016-09-01

Head-up Display (HUD) is a safety feature for automobile drivers. Although there have been some HUD systems in commercial product already, their images are too small to show assistance information. Another problem, the volume of HUD is too large. We proposed a HUD including micro-projectors, rear-projection screen, microlens array (MLA) and the light source is 28 mm x 14 mm realized a 200 mm x 100 mm image in 3 meters from drivers. We want to use the MLA to reduce the volume by virtual image stitching. We design the HUD's package dimensions is 12 cm x 12 cm x 9 cm. It is able to show speed, map-navigation and night vision information. We used Liquid Crystal Display (LCD) as our image source due to its brighter image output required and the minimum volume occupancy. The MLA is a multi aperture system. The proposed MLA consists of many optical channels each transmitting a segment of the whole field of view. The design of the system provides the stitching of the partial images, so that we can see the whole virtual image.

Characterization of multiaxial warp knit composites

NASA Technical Reports Server (NTRS)

Dexter, H. Benson; Hasko, Gregory H.; Cano, Roberto J.

1991-01-01

The objectives were to characterize the mechanical behavior and damage tolerance of two multiaxial warp knit fabrics to determine the acceptability of these fabrics for high performance composite applications. The tests performed included compression, tension, open hole compression, compression after impact and compression-compression fatigue. Tests were performed on as-fabricated fabrics and on multi-layer fabrics that were stitched together with either carbon or Kevlar stitching yarn. Results of processing studies for vacuum impregnation with Hercules 3501-6 epoxy resin and pressure impregnation with Dow Tactix 138/H41 epoxy resin and British Petroleum BP E905L epoxy resin are presented.

Enhanced resolution and accuracy of freeform metrology through Subaperture Stitching Interferometry

NASA Astrophysics Data System (ADS)

Supranowitz, Chris; Maloney, Chris; Murphy, Paul; Dumas, Paul

2017-10-01

Recent advances in polishing and metrology have addressed many of the challenges in the fabrication and metrology of freeform surfaces, and the manufacture of these surfaces is possible today. However, achieving the form and mid-spatial frequency (MSF) specifications that are typical of visible imaging systems remains a challenge. Interferometric metrology for freeform surfaces is thus highly desirable for such applications, but the capability is currently quite limited for freeforms. In this paper, we provide preliminary results that demonstrate accurate, high-resolution measurements of freeform surfaces using prototype software on QED's ASI™ (Aspheric Stitching Interferometer).

Experimental Observations of a Stitched Composite with a Notch Subjected to Combined Bending and Tension Loading

NASA Technical Reports Server (NTRS)

Palmer, Susan O.; Nettles, Alan T.; Poe, C. C.

1998-01-01

A series of tests was conducted to support development of an analytical model for predicting the failure strains of stitched warp-knit carbon/epoxy composite materials with through-thicknesss damage in the form of a crack-like notch. Measurements of strain near notch tips, crack opening displacement (COD), and applied load were monitored in all tests. The out-of-plane displacement at the center of the notch was also measured when the specimen was subjected to bending. Three types of loading were applied: pure bending, pure tension, and combined bending and tension.

Bonded and Stitched Composite Structure

NASA Technical Reports Server (NTRS)

Zalewski, Bart F. (Inventor); Dial, William B. (Inventor)

2014-01-01

A method of forming a composite structure can include providing a plurality of composite panels of material, each composite panel having a plurality of holes extending through the panel. An adhesive layer is applied to each composite panel and a adjoining layer is applied over the adhesive layer. The method also includes stitching the composite panels, adhesive layer, and adjoining layer together by passing a length of a flexible connecting element into the plurality of holes in the composite panels of material. At least the adhesive layer is cured to bond the composite panels together and thereby form the composite structure.

RealityFlythrough: Enhancing Situational Awareness for Medical Response to Disasters Using Ubiquitous Video

PubMed Central

McCurdy, Neil J.; Griswold, William G; Lenert, Leslie A.

2005-01-01

The first moments at a disater scene are chaotic. The command center initially operates with little knowledge of hazards, geography and casualties, building up knowledge of the event slowly as information trickles in by voice radio channels. RealityFlythrough is a tele-presence system that stitches together live video feeds in real-time, using the principle of visual closure, to give command center personnel the illusion of being able to explore the scene interactively by moving smoothly between the video feeds. Using RealityFlythrough, medical, fire, law enforcement, hazardous materials, and engineering experts may be able to achieve situational awareness earlier, and better manage scarce resources. The RealityFlythrough system is composed of camera units with off-the-shelf GPS and orientation systems and a server/viewing station that offers access to images collected by the camera units in real time by position/orientation. In initial field testing using an experimental mesh 802.11 wireless network, two camera unit operators were able to create an interactive image of a simulated disaster scene in about five minutes. PMID:16779092

Evaluation of clinical curative effects of disposable stitching instrument in redundant prepuce patients

PubMed Central

Wang, Haitao; Chen, Ningjie; Huo, Ran; Yang, Jincun; Li, Xia; Xing, Nan

2017-01-01

The present study aimed to investigate the clinical curative effect of disposable stitching instrument operation in patients with redundant prepuce or phimosis. A total of 102 cases of patients with circumcision were randomly selected (from June 2013 to December 2014) from the department of plastic and aesthetic surgery of our hospital and were randomly divided into control and observation groups (n=51). Patients in the control group were treated by traditional circumcision operation, while patients in the observation group were treated by novel disposable circumcision stitching instrument. Operation time, bleeding volume, incision healing time, postoperative complications and incision aesthetic satisfaction in the groups were observed. As a result, intraoperative bleeding volume of patients in the observation group was significantly less in comparison to the control group. Operation time and incision healing time of patients in the observation group was shorter than that of the control group. Additionally, the incidence of postoperative complications of patients in the observation group was noted to be lower than that of the control group. On the other hand, the incision aesthetic satisfaction of patients in the observation group was higher than that of the control group. Blood vessel counting and nerve fiber counting of tissue specimen in the observation group were more than those of the control group. Postoperative VAS scores of patients in the observation group were significantly lower than that of the control group. Each rating scale scores of EPQ of patients in the observation group improved significantly compared with that of the control group. In conclusion, the present findings show that disposable circumcision stitching instrument operation is more advantageous in comparison to the traditional procedure along with minimal compilations and better post surgery health condition of patients. PMID:28672929

Measurement and analysis of flow in 3D preforms for aerospace composites

NASA Astrophysics Data System (ADS)

Stewart, Andrew Lawrence

Composite materials have become viable alternatives to traditional engineering materials for many different product categories. Liquid transfer moulding (LTM) processes, specifically resin transfer moulding (RTM), is a cost-effective manufacturing technique for creating high performance composite parts. These parts can be tailor-made to their specific application by optimizing the properties of the textile preform. Preforms which require little or no further assembly work and are close to the shape of the final part are critical to obtaining high quality parts while simultaneously reducing labour and costs associated with other composite manufacturing techniques. One type of fabric which is well suited for near-net- shape preforms is stitched non-crimp fabrics. These fabrics offer very high in-plane strength and stiffness while also having increased resistance to delamination. Manufacturing parts from these dry preforms typically involves long-scale fluid flow through both open channels and porous fibre bundles. This thesis documents and analyzes the flow of fluid through preforms manufactured from non-crimp fabrics featuring through-thickness stitches. The objective of this research is to determine the effect of this type of stitch on the RTM injection process. All of the tests used preforms with fibre volume fractions representative of primary and secondary structural parts. A series of trials was conducted using different fibre materials, flow rates, fibre volumes fractions, and degrees of fibre consolidation. All of the trials were conducted for cases similar to RTM. Consolidation of the fibres showed improvements to both the thoroughness of the filling and to the fibre volume fraction. Experimentally determined permeability data was shown to trend well with simple models and precision of the permeability data was comparable to values presented by other authors who studied fabrics which did not feature the through-thickness stitches.

Biomechanical comparison of four double-row speed-bridging rotator cuff repair techniques with or without medial or lateral row enhancement.

PubMed

Pauly, Stephan; Fiebig, David; Kieser, Bettina; Albrecht, Bjoern; Schill, Alexander; Scheibel, Markus

2011-12-01

Biomechanical comparison of four different Speed-Bridge configurations with or without medial or lateral row reinforcement. Reinforcement of the knotless Speed-Bridge double-row repair technique with additional medial mattress- or lateral single-stitches was hypothesized to improve biomechanical repair stability at time zero. Controlled laboratory study: In 36 porcine fresh-frozen shoulders, the infraspinatus tendons were dissected and shoulders were randomized to four groups: (1) Speed-Bridge technique with single tendon perforation per anchor (STP); (2) Speed-Bridge technique with double tendon perforation per anchor (DTP); (3) Speed-Bridge technique with medial mattress-stitch reinforcement (MMS); (4) Speed-Bridge technique with lateral single-stitch reinforcement (LSS). All repairs were cyclically loaded from 10-60 N up to 10-200 N (20 N stepwise increase) using a material testing device. Forces at 3 and 5 mm gap formation, mode of failure and maximum load to failure were recorded. The MMS-technique with double tendon perforation showed significantly higher ultimate tensile strength (338.9 ± 90.0 N) than DTP (228.3 ± 99.9 N), LSS (188.9 ± 62.5 N) and STP-technique (122.2 ± 33.8 N). Furthermore, the MMS-technique provided increased maximal force resistance until 3 and 5 mm gap formation (3 mm: 77.8 ± 18.6 N; 5 mm: 113.3 ± 36.1 N) compared with LSS, DTP and STP (P < 0.05 for each 3 and 5 mm gap formation). Failure mode was medial row defect by tendon sawing first, then laterally. No anchor pullout occurred. Double tendon perforation per anchor and additional medial mattress stitches significantly enhance biomechanical construct stability at time zero in this ex vivo model when compared with the all-knotless Speed-Bridge rotator cuff repair.

Automatic Intra-Operative Stitching of Non-Overlapping Cone-Beam CT Acquisitions

PubMed Central

Fotouhi, Javad; Fuerst, Bernhard; Unberath, Mathias; Reichenstein, Stefan; Lee, Sing Chun; Johnson, Alex A.; Osgood, Greg M.; Armand, Mehran; Navab, Nassir

2018-01-01

Purpose Cone-Beam Computed Tomography (CBCT) is one of the primary imaging modalities in radiation therapy, dentistry, and orthopedic interventions. While CBCT provides crucial intraoperative information, it is bounded by a limited imaging volume, resulting in reduced effectiveness. This paper introduces an approach allowing real-time intraoperative stitching of overlapping and non-overlapping CBCT volumes to enable 3D measurements on large anatomical structures. Methods A CBCT-capable mobile C-arm is augmented with a Red-Green-Blue-Depth (RGBD) camera. An off-line co-calibration of the two imaging modalities results in co-registered video, infrared, and X-ray views of the surgical scene. Then, automatic stitching of multiple small, non-overlapping CBCT volumes is possible by recovering the relative motion of the C-arm with respect to the patient based on the camera observations. We propose three methods to recover the relative pose: RGB-based tracking of visual markers that are placed near the surgical site, RGBD-based simultaneous localization and mapping (SLAM) of the surgical scene which incorporates both color and depth information for pose estimation, and surface tracking of the patient using only depth data provided by the RGBD sensor. Results On an animal cadaver, we show stitching errors as low as 0.33 mm, 0.91 mm, and 1.72mm when the visual marker, RGBD SLAM, and surface data are used for tracking, respectively. Conclusions The proposed method overcomes one of the major limitations of CBCT C-arm systems by integrating vision-based tracking and expanding the imaging volume without any intraoperative use of calibration grids or external tracking systems. We believe this solution to be most appropriate for 3D intraoperative verification of several orthopedic procedures. PMID:29569728

Sliceable transponders for metro-access transmission links

NASA Astrophysics Data System (ADS)

Wagner, C.; Madsen, P.; Spolitis, S.; Vegas Olmos, J. J.; Tafur Monroy, I.

2015-01-01

This paper presents a solution for upgrading optical access networks by reusing existing electronics or optical equipment: sliceable transponders using signal spectrum slicing and stitching back method after direct detection. This technique allows transmission of wide bandwidth signals from the service provider (OLT - optical line terminal) to the end user (ONU - optical network unit) over an optical distribution network (ODN) via low bandwidth equipment. We show simulation and experimental results for duobinary signaling of 1 Gbit/s and 10 Gbit/s waveforms. The number of slices is adjusted to match the lowest analog bandwidth of used electrical devices and scale from 2 slices to 10 slices. Results of experimental transmission show error free signal recovery by using post forward error correction with 7% overhead.

KSC-04pd0615

NASA Image and Video Library

2004-03-24

KENNEDY SPACE CENTER, FLA. -- A closeup of the stitching being done on pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

Effects of thermal and moisture cycling on the internal structure of stitched RTM laminates

NASA Technical Reports Server (NTRS)

Walker, Jeff; Roundy, Lance; Goering, Jon

1993-01-01

Conventional aerospace composites are strong and stiff in the directions parallel to the carbon fibers, but they are prone to delaminations and damage in the through-the-thickness directions. Recent research has shown that substantial improvements in damage tolerance are obtained from textile composites with Z-direction reinforcement provided by stitching, weaving, or braiding. Because of the mismatch in thermal and moisture expansion properties of the various material components, there is a potential for microcracks to develop in the resin matrix. These cracks can form to relieve the mechanical stresses that are generated during curing or in-service temperature cycles.

Method of repairing discontinuity in fiberglass structures

NASA Technical Reports Server (NTRS)

Gelb, L. L.; Helbert, W. B., Jr.; Enie, R. B.; Mulliken, R. F. (Inventor)

1974-01-01

Damaged fiberglass structures are repaired by substantially filling the irregular surfaced damaged area with a liquid, self-curing resin, preferably an epoxy resin mixed with chopped fiberglass, and then applying to the resin surface the first of several woven fiberglass swatches which has stitching in a zig-zag pattern parallel to each of its edges and a fringe of warp and fill glass fibers about the edges outward of the stitching. The method is especially applicable to repair of fiberglass rocket engine casings and is particularly advantageous since it restores the repaired fiberglass structure to substantially its original strength without any significant changes in the geometry or mass of the structure.

Scanning superlens microscopy for non-invasive large field-of-view visible light nanoscale imaging

NASA Astrophysics Data System (ADS)

Wang, Feifei; Liu, Lianqing; Yu, Haibo; Wen, Yangdong; Yu, Peng; Liu, Zhu; Wang, Yuechao; Li, Wen Jung

2016-12-01

Nanoscale correlation of structural information acquisition with specific-molecule identification provides new insight for studying rare subcellular events. To achieve this correlation, scanning electron microscopy has been combined with super-resolution fluorescent microscopy, despite its destructivity when acquiring biological structure information. Here we propose time-efficient non-invasive microsphere-based scanning superlens microscopy that enables the large-area observation of live-cell morphology or sub-membrane structures with sub-diffraction-limited resolution and is demonstrated by observing biological and non-biological objects. This microscopy operates in both non-invasive and contact modes with ~200 times the acquisition efficiency of atomic force microscopy, which is achieved by replacing the point of an atomic force microscope tip with an imaging area of microspheres and stitching the areas recorded during scanning, enabling sub-diffraction-limited resolution. Our method marks a possible path to non-invasive cell imaging and simultaneous tracking of specific molecules with nanoscale resolution, facilitating the study of subcellular events over a total cell period.

Structural Performance of a Compressively Loaded Foam-Core Hat-Stiffened Textile Composite Panel

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.; Dexter, Benson H.

1996-01-01

A structurally efficient hat-stiffened panel concept that utilizes a structural foam as a stiffener core material has been designed and developed for aircraft primary structural applications. This stiffener concept is fabricated from textile composite material forms with a resin transfer molding process. This foam-filled hat-stiffener concept is structurally more efficient than most other prismatically stiffened panel configurations in a load range that is typical for both fuselage and wing structures. The panel design is based on woven/stitched and braided graphite-fiber textile preforms, an epoxy resin system, and Rohacell foam core. The structural response of this panel design was evaluated for its buckling and postbuckling behavior with and without low-speed impact damage. The results from single-stiffener and multi-stiffener specimen tests suggest that this structural concept responds to loading as anticipated and has excellent damage tolerance characteristics compared to a similar panel design made from preimpregnated graphite-epoxy tape material.

Matrix decomposition graphics processing unit solver for Poisson image editing

NASA Astrophysics Data System (ADS)

Lei, Zhao; Wei, Li

2012-10-01

In recent years, gradient-domain methods have been widely discussed in the image processing field, including seamless cloning and image stitching. These algorithms are commonly carried out by solving a large sparse linear system: the Poisson equation. However, solving the Poisson equation is a computational and memory intensive task which makes it not suitable for real-time image editing. A new matrix decomposition graphics processing unit (GPU) solver (MDGS) is proposed to settle the problem. A matrix decomposition method is used to distribute the work among GPU threads, so that MDGS will take full advantage of the computing power of current GPUs. Additionally, MDGS is a hybrid solver (combines both the direct and iterative techniques) and has two-level architecture. These enable MDGS to generate identical solutions with those of the common Poisson methods and achieve high convergence rate in most cases. This approach is advantageous in terms of parallelizability, enabling real-time image processing, low memory-taken and extensive applications.

Time efficient Gabor fused master slave optical coherence tomography

NASA Astrophysics Data System (ADS)

Cernat, Ramona; Bradu, Adrian; Rivet, Sylvain; Podoleanu, Adrian

2018-02-01

In this paper the benefits in terms of operation time that Master/Slave (MS) implementation of optical coherence tomography can bring in comparison to Gabor fused (GF) employing conventional fast Fourier transform based OCT are presented. The Gabor Fusion/Master Slave Optical Coherence Tomography architecture proposed here does not need any data stitching. Instead, a subset of en-face images is produced for each focus position inside the sample to be imaged, using a reduced number of theoretically inferred Master masks. These en-face images are then assembled into a final volume. When the channelled spectra are digitized into 1024 sampling points, and more than 4 focus positions are required to produce the final volume, the Master Slave implementation of the instrument is faster than the conventional fast Fourier transform based procedure.

Adaptation of a cubic smoothing spline algortihm for multi-channel data stitching at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, C; Adcock, A; Azevedo, S

2010-12-28

Some diagnostics at the National Ignition Facility (NIF), including the Gamma Reaction History (GRH) diagnostic, require multiple channels of data to achieve the required dynamic range. These channels need to be stitched together into a single time series, and they may have non-uniform and redundant time samples. We chose to apply the popular cubic smoothing spline technique to our stitching problem because we needed a general non-parametric method. We adapted one of the algorithms in the literature, by Hutchinson and deHoog, to our needs. The modified algorithm and the resulting code perform a cubic smoothing spline fit to multiple datamore » channels with redundant time samples and missing data points. The data channels can have different, time-varying, zero-mean white noise characteristics. The method we employ automatically determines an optimal smoothing level by minimizing the Generalized Cross Validation (GCV) score. In order to automatically validate the smoothing level selection, the Weighted Sum-Squared Residual (WSSR) and zero-mean tests are performed on the residuals. Further, confidence intervals, both analytical and Monte Carlo, are also calculated. In this paper, we describe the derivation of our cubic smoothing spline algorithm. We outline the algorithm and test it with simulated and experimental data.« less

A simple method for panretinal imaging with the slit lamp.

PubMed

Gellrich, Marcus-Matthias

2016-12-01

Slit lamp biomicroscopy of the retina with a convex lens is a key procedure in clinical practice. The methods presented enable ophthalmologists to adequately image large and peripheral parts of the fundus using a video-slit lamp and freely available stitching software. A routine examination of the fundus with a slit lamp and a +90 D lens is recorded on a video film. Later, sufficiently sharp still images are identified on the video sequence. These still images are imported into a freely available image-processing program (Hugin, for stitching mosaics together digitally) and corresponding points are marked on adjacent still images with some overlap. Using the digital stitching program Hugin panoramic overviews of the retina can be built which can extend to the equator. This allows to image diseases involving the whole retina or its periphery by performing a structured fundus examination with a video-slit lamp. Similar images with a video-slit lamp based on a fundus examination through a hand-held non-contact lens have not been demonstrated before. The methods presented enable those ophthalmologists without high-end imaging equipment to monitor pathological fundus findings. The suggested procedure might even be interesting for retinological departments if peripheral findings are to be documented which might be difficult with fundus cameras.

Fixation of the Achilles tendon insertion using suture button technology.

PubMed

Fanter, Nathan J; Davis, Edward W; Baker, Champ L

2012-09-01

In the operative treatment of Achilles insertional tendinopathy, no guidelines exist concerning which form of fixation of the Achilles tendon insertion is superior. Transcalcaneal drill pin passage does not place any major plantar structures at risk, and the addition of a Krackow stitch and suture button to the fixation technique provides a significant increase in ultimate load to failure in Achilles tendon insertional repairs. Controlled laboratory study. The Achilles tendon insertions in 6 fresh-frozen cadaveric ankles were detached, and transcalcaneal drill pins were passed. Plantar dissection took place to evaluate the drill pin relationship to the plantar fascia, lateral plantar nerve and artery, flexor digitorum longus tendon, and master knot of Henry. The Achilles tendons were then repaired with a double-row suture anchor construct alone or with a suture button and Krackow stitch added to the double-row suture anchor construct. The repairs were then tested to maximum load to failure at 20 mm/min. The mode of failure was recorded, and the mean maximum load to failure was assessed using the Student t test for distributions with equal variance. Transcalcaneal drill pin passage did not place any selected anatomic structures at risk. The mean maximum load to failure for the suture bridge group was 239.2 N; it was 391.4 N for the group with the suture button (P = .014). The lateral plantar artery was the structure placed at greatest risk from drill pin placement, with a mean distance of 22.7 mm (range, 16.5-29.2 mm) between the pin and artery. In this laboratory study, transcalcaneal drill pin passage appeared to be anatomically safe, and the use of suture button technology with a Krackow stitch for Achilles tendon insertional repair significantly increased repair strength. Achilles tendon insertional repair with suture button fixation and a Krackow stitch may facilitate the earlier institution of postoperative rehabilitation and improve clinical outcomes.

U-stitching splenorraphy technique: experimental and clinical study.

PubMed

Tsaroucha, Alexandra K; Pitiakoudis, Michail S; Chanos, Georgios; Chiotis, Anestis S; Argyropoulou, Paraskevi I; Prassopoulos, Panos; Simopoulos, Constantinos E

2005-04-01

The aim of the present study was to describe the laboratory development and the subsequent clinical utility of the U-stitching technique for splenorraphy over the recent years in a general non-trauma hospital. Patients with splenectomies and patients treated conservatively during the same time period, are also presented. In the 15-year period from September 1988 until September 2003, 65 patients were diagnosed with splenic injury following admission to 2nd Department of Surgery, Democritus University Hospital, after blunt abdominal trauma. During the first 3 years, 14 patients were admitted; one of them was treated conservatively and 13 had splenectomies. Because computed tomography (CT) was not available at that time, these 14 patients form a control group. During the remaining 12-year period, 51 patients (39 male and 12 female; age, 4-82 years; mean, 31.1 years; SD, 19.7 years) were treated conservatively or surgically, either with splenectomy or with splenorraphy. Splenorraphy was performed using the U-stitching technique. This alternative splenorraphy technique was first tested on experimental models at 2nd Department of Surgery, Democritus University Hospital, then followed by successful clinical application. The medical records for these patients were reviewed to extract the data for the present study. Thirty-six patients (70.6% of 51 patients) were treated surgically; of these, 21 (41.2% of 51 patients) had splenectomy and 15 (29.4% of 51 patients) had splenorraphy. Non-operative treatment was initially given to 15 patients (29.4% of 51 patients). Two of them had delayed rupture of the spleen and underwent splenectomy (at 8 and 40 days). The total number of preserved spleens was 28 of 51 (54.9%). None of the patients with conservative treatment or splenorraphy died. One patient with splenectomy died later from overwhelming sepsis. Splenic salvage is now a treatment goal. If the patient is haemodynamically unstable and splenorraphy is possible, the U-stitching technique is a promising approach.

Nonlinear Analysis and Post-Test Correlation for a Curved PRSEUS Panel

NASA Technical Reports Server (NTRS)

Gould, Kevin; Lovejoy, Andrew E.; Jegley, Dawn; Neal, Albert L.; Linton, Kim, A.; Bergan, Andrew C.; Bakuckas, John G., Jr.

2013-01-01

The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept, developed by The Boeing Company, has been extensively studied as part of the National Aeronautics and Space Administration's (NASA s) Environmentally Responsible Aviation (ERA) Program. The PRSEUS concept provides a light-weight alternative to aluminum or traditional composite design concepts and is applicable to traditional-shaped fuselage barrels and wings, as well as advanced configurations such as a hybrid wing body or truss braced wings. Therefore, NASA, the Federal Aviation Administration (FAA) and The Boeing Company partnered in an effort to assess the performance and damage arrestments capabilities of a PRSEUS concept panel using a full-scale curved panel in the FAA Full-Scale Aircraft Structural Test Evaluation and Research (FASTER) facility. Testing was conducted in the FASTER facility by subjecting the panel to axial tension loads applied to the ends of the panel, internal pressure, and combined axial tension and internal pressure loadings. Additionally, reactive hoop loads were applied to the skin and frames of the panel along its edges. The panel successfully supported the required design loads in the pristine condition and with a severed stiffener. The panel also demonstrated that the PRSEUS concept could arrest the progression of damage including crack arrestment and crack turning. This paper presents the nonlinear post-test analysis and correlation with test results for the curved PRSEUS panel. It is shown that nonlinear analysis can accurately calculate the behavior of a PRSEUS panel under tension, pressure and combined loading conditions.

Thermal insulating conformal blanket

NASA Technical Reports Server (NTRS)

Barney, Andrea (Inventor); Whittington, Charles A (Inventor); Eilertson, Bryan (Inventor); Siminski, Zenon (Inventor)

2003-01-01

The conformal thermal insulating blanket may have generally rigid batting material covered by an outer insulating layer formed of a high temperature resistant woven ceramic material and an inner insulating layer formed of a woven ceramic fiber material. The batting and insulating layers may be fastened together by sewing or stitching using an outer mold layer thread fabricated of a high temperature resistant material and an inner mold layer thread of a ceramic fiber material. The batting may be formed to a composite structure that may have a firmness factor sufficient to inhibit a pillowing effect after the stitching to not more than 0.03 inch. The outer insulating layer and an upper portion of the batting adjacent the outer insulating layer may be impregnated with a ceramic coating material.

Development of broadband X-ray interference lithography large area exposure system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xue, Chaofan; Wu, Yanqing, E-mail: wuyanqing@sinap.ac.cn, E-mail: zhaojun@sinap.ac.cn, E-mail: tairenzhong@sinap.ac.cn; Zhu, Fangyuan

2016-04-15

The single-exposure patterned area is about several 10{sup 2} × 10{sup 2} μm{sup 2} which is mainly decided by the mask area in multi-beam X-ray interference lithography (XIL). The exposure area is difficult to stitch to a larger one because the patterned area is surrounded by 0th diffraction exposure areas. To block the 0th diffraction beams precisely and effectively, a new large area exposure technology is developed in the Shanghai Synchrotron Radiation Facility by applying an order-sorting aperture with a new in situ monitoring scheme in the XIL system. The patterned area could be stitched readily up to several squaremore » centimeters and even bigger by this technology.« less

An Experimental Study of a Stitched Composite with a Notch Subjected to Combined Bending and Tension Loading

NASA Technical Reports Server (NTRS)

Palmer, Susan O.; Nettles, Alan T.; Poe, C. C., Jr.

1999-01-01

A series of tests was conducted to measure the strength of stitched carbon/epoxy composites containing through-thickness damage in the form of a crack-like notch. The specimens were subjected to three types of loading: pure bending, pure tension, and combined bending and tension loads. Measurements of applied loads, strains near crack tips, and crack opening displacements (COD) were monitored in all tests. The transverse displacement at the center of the specimen was measured using a Linear Variable Differential Transformer (LVDT). The experimental data showed that the outer surface of the pure tension specimen failed at approximately 6,000 microstrain, while in combined bending and tension loads the measured tensile strains reached 10,000 microstrain.

Micromechanics of fatigue in woven and stitched composites

NASA Technical Reports Server (NTRS)

Cox, B. N.; Carter, W. C.; Dadkhah, M. S.; Morris, W. L.

1994-01-01

The goals of this research program were to: (1) determine how microstructural factors, especially the architecture of reinforcing fibers, control stiffness, strength, and fatigue life in 3D woven composites; (2) identify mechanisms of failure; (3) model composite stiffness; (4) model notched and unnotched strength; and (5) model fatigue life. We have examined a total of eleven different angle and orthogonal interlock woven composites. Extensive testing has revealed that these 3D woven composites possess an extraordinary combination of strength, damage tolerance, and notch insensitivity in compression and tension and in monotonic and cyclic loading. In many important regards, 3D woven composites far outstrip conventional 2D laminates or stitched laminates. Detailed microscopic analysis of damage has led to a comprehensive picture of the essential mechanisms of failure and how they are related to the reinforcement geometry. The critical characteristics of the weave architecture that promote favorable properties have been identified. Key parameters are tow size and the distributions in space and strength of geometrical flaws. The geometrical flaws should be regarded as controllable characteristics of the weave in design and manufacture. In addressing our goals, the simplest possible models of properties were always sought, in a blend of old and new modeling concepts. Nevertheless, certain properties, especially regarding damage tolerance, ultimate failure, and the detailed effects of weave architecture, require computationally intensive stochastic modeling. We have developed a new model, the 'binary model,' to carry out such tasks in the most efficient manner and with faithful representation of crucial mechanisms. This is the final report for contract NAS1-18840. It covers all work from April 1989 up to the conclusion of the program in January 1993.

A new training model for robot-assisted urethrovesical anastomosis and posterior muscle-fascial reconstruction: the Verona training technique.

PubMed

Cacciamani, G; De Marco, V; Siracusano, S; De Marchi, D; Bizzotto, L; Cerruto, M A; Motton, G; Porcaro, A B; Artibani, W

2017-06-01

A training model is usually needed to teach robotic surgical technique successfully. In this way, an ideal training model should mimic as much as possible the "in vivo" procedure and allow several consecutive surgical simulations. The goal of this study was to create a "wet lab" model suitable for RARP training programs, providing the simulation of the posterior fascial reconstruction. The second aim was to compare the original "Venezuelan" chicken model described by Sotelo to our training model. Our training model consists of performing an anastomosis, reproducing the surgical procedure in "vivo" as in RARP, between proventriculus and the proximal portion of the esophagus. A posterior fascial reconstruction simulating Rocco's stitch is performed between the tissues located under the posterior surface of the esophagus and the tissue represented by the serosa of the proventriculus. From 2014 to 2015, during 6 different full-immersion training courses, thirty-four surgeons performed the urethrovesical anastomosis using our model and the Sotelo's one. After the training period, each surgeon was asked to fill out a non-validated questionnaire to perform an evaluation of the differences between the two training models. Our model was judged the best model, in terms of similarity with urethral tissue and similarity with the anatomic unit urethra-pelvic wall. Our training model as reported by all trainees is easily reproducible and anatomically comparable with the urethrovesical anastomosis as performed during radical prostatectomy in humans. It is suitable for performing posterior fascial reconstruction reported by Rocco. In this context, our surgical training model could be routinely proposed in all robotic training courses to develop specific expertise in urethrovesical anastomosis with the reproducibility of the Rocco stitch.

Risk and protective factors for falls on one level in young children: multicentre case-control study.

PubMed

Benford, P; Young, B; Coupland, C; Watson, M; Hindmarch, P; Hayes, M; Goodenough, T; Majsak-Newman, G; Kendrick, D

2015-12-01

Childhood falls are an important global public health problem, but there is lack of evidence about their prevention. Falls on one level result in considerable morbidity and they are costly to health services. To estimate ORs for falls on one level in children aged 0-4 years for a range of safety behaviours, safety equipment use and home hazards. Multicentre case-control study at hospitals, minor injury units and general practices in and around four UK study centres. Participants included 582 children less than 5 years of age with a medically attended fall injury occurring at home and 2460 controls matched on age, sex, calendar time and study centre. Fall on one level. Cases' most common injuries were bangs on the head (52%), cuts or grazes not needing stitches (29%) or cuts or grazes needing stitches (17%). Comparing cases to community controls in the adjusted analyses, significant findings were observed for only two exposures. Injured children were significantly less likely to live in a household without furniture corner covers (adjusted OR (AOR) 0.72, 95% CI 0.55 to 0.95), or without rugs and carpets firmly fixed to the floor (AOR 0.76, 95% CI 0.59 to 0.98). We did not find any safety practices, use of safety equipment or home hazards associated with a reduced risk of fall on one level. Our findings do not provide evidence to support changes to current injury prevention practice. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Novel Composites for Wing and Fuselage Applications. Task 1; Novel Wing Design Concepts

NASA Technical Reports Server (NTRS)

Suarez, J. A.; Buttitta, C.; Flanagan, G.; DeSilva, T.; Egensteiner, W.; Bruno, J.; Mahon, J.; Rutkowski, C.; Collins, R.; Fidnarick, R.;

Ultrahigh-speed non-invasive widefield angiography

NASA Astrophysics Data System (ADS)

Blatter, Cedric; Klein, Thomas; Grajciar, Branislav; Schmoll, Tilman; Wieser, Wolfgang; Andre, Raphael; Huber, Robert; Leitgeb, Rainer A.

2012-07-01

Retinal and choroidal vascular imaging is an important diagnostic benefit for ocular diseases such as age-related macular degeneration. The current gold standard for vessel visualization is fluorescence angiography. We present a potential non-invasive alternative to image blood vessels based on functional Fourier domain optical coherence tomography (OCT). For OCT to compete with the field of view and resolution of angiography while maintaining motion artifacts to a minimum, ultrahigh-speed imaging has to be introduced. We employ Fourier domain mode locking swept source technology that offers high quality imaging at an A-scan rate of up to 1.68 MHz. We present retinal angiogram over ˜48 deg acquired in a few seconds in a single recording without the need of image stitching. OCT at 1060 nm allows for high penetration in the choroid and efficient separate characterization of the retinal and choroidal vascularization.

Method for stitching microbial images using a neural network

NASA Astrophysics Data System (ADS)

Semenishchev, E. A.; Voronin, V. V.; Marchuk, V. I.; Tolstova, I. V.

2017-05-01

Currently an analog microscope has a wide distribution in the following fields: medicine, animal husbandry, monitoring technological objects, oceanography, agriculture and others. Automatic method is preferred because it will greatly reduce the work involved. Stepper motors are used to move the microscope slide and allow to adjust the focus in semi-automatic or automatic mode view with transfer images of microbiological objects from the eyepiece of the microscope to the computer screen. Scene analysis allows to locate regions with pronounced abnormalities for focusing specialist attention. This paper considers the method for stitching microbial images, obtained of semi-automatic microscope. The method allows to keep the boundaries of objects located in the area of capturing optical systems. Objects searching are based on the analysis of the data located in the area of the camera view. We propose to use a neural network for the boundaries searching. The stitching image boundary is held of the analysis borders of the objects. To auto focus, we use the criterion of the minimum thickness of the line boundaries of object. Analysis produced the object located in the focal axis of the camera. We use method of recovery of objects borders and projective transform for the boundary of objects which are based on shifted relative to the focal axis. Several examples considered in this paper show the effectiveness of the proposed approach on several test images.

Multi-camera digital image correlation method with distributed fields of view

NASA Astrophysics Data System (ADS)

Malowany, Krzysztof; Malesa, Marcin; Kowaluk, Tomasz; Kujawinska, Malgorzata

2017-11-01

A multi-camera digital image correlation (DIC) method and system for measurements of large engineering objects with distributed, non-overlapping areas of interest are described. The data obtained with individual 3D DIC systems are stitched by an algorithm which utilizes the positions of fiducial markers determined simultaneously by Stereo-DIC units and laser tracker. The proposed calibration method enables reliable determination of transformations between local (3D DIC) and global coordinate systems. The applicability of the method was proven during in-situ measurements of a hall made of arch-shaped (18 m span) self-supporting metal-plates. The proposed method is highly recommended for 3D measurements of shape and displacements of large and complex engineering objects made from multiple directions and it provides the suitable accuracy of data for further advanced structural integrity analysis of such objects.

Cauliflower Ear

MedlinePlus

... of headgear are recommended or required (like football, baseball, hockey, boxing, or wrestling). If someone receives a ... Taking Care of Your Skin Stitches Stay Safe: Baseball What's a Bruise? View more About Us Contact ...

PREVAIL: latest electron optics results

NASA Astrophysics Data System (ADS)

Pfeiffer, Hans C.; Golladay, Steven D.; Gordon, Michael S.; Kendall, Rodney A.; Lieberman, Jon E.; Rockrohr, James D.; Stickel, Werner; Yamaguchi, Takeshi; Okamoto, Kazuya; Umemoto, Takaaki; Shimizu, Hiroyasu; Kojima, Shinichi; Hamashima, Muneki

2002-07-01

The PREVAIL electron optics subsystem developed by IBM has been installed at Nikon's facility in Kumagaya, Japan, for integration into the Nikon commercial EPL stepper. The cornerstone of the electron optics design is the Curvilinear Variable Axis Lens (CVAL) technique originally demonstrated with a proof of concept system. This paper presents the latest experimental results obtained with the electron optical subsystem at Nikon's facility. The results include micrographs illustrating proper CVAL operation through the spatial resolution achieved over the entire optical field of view. They also include data on the most critical issue of the EPL exposure approach: subfield stitching. The methodology of distortion correction will be described and both micrographs and metrology data of stitched subfields will be presented. This paper represents a progress report of the IBM/Nikon alliance activity on EPL.

A methodology for double patterning compliant split and design

NASA Astrophysics Data System (ADS)

Wiaux, Vincent; Verhaegen, Staf; Iwamoto, Fumio; Maenhoudt, Mireille; Matsuda, Takashi; Postnikov, Sergei; Vandenberghe, Geert

2008-11-01

Double Patterning allows to further extend the use of water immersion lithography at its maximum numerical aperture NA=1.35. Splitting of design layers to recombine through Double Patterning (DP) enables an effective resolution enhancement. Single polygons may need to be split up (cut) depending on the pattern density and its 2D content. The split polygons recombine at the so-called 'stitching points'. These stitching points may affect the yield due to the sensitivity to process variations. We describe a methodology to ensure a robust double patterning by identifying proper split- and design- guidelines. Using simulations and experimental data, we discuss in particular metal1 first interconnect layers of random LOGIC and DRAM applications at 45nm half-pitch (hp) and 32nm hp where DP may become the only timely patterning solution.

KSC-2011-1497

NASA Image and Video Library

2011-02-18

CAPE CANAVERAL, Fla. -- More than a dozen 9/11 first responders take part in "The National 9/11 Flag" stitching ceremony at the Kennedy Space Center Visitor Complex in Florida. The contributions of NASA, Kennedy Space Center and the state of Florida were stitched into the fabric of the American Flag, which was recovered near ground zero following the World Trade Center attacks on Sept. 11, 2001. The "New York Says Thank You Foundation" is taking the flag on a cross-country journey to be restored to its original 13-stripe design using pieces of fabric from American flags destined for retirement in all 50 states. Once the flag is restored, it will become a permanent collection of the National September 11 Memorial Museum being built at the World Trade Center site. Photo credit: NASA/Kim Shiflett

Physical interpretation and development of ultrasonic nondestructive evaluation techniques applied to the quantitative characterization of textile composite materials

NASA Technical Reports Server (NTRS)

Miller, James G.

1993-01-01

In this Progress Report, we describe our current research activities concerning the development and implementation of advanced ultrasonic nondestructive evaluation methods applied to the characterization of stitched composite materials and bonded aluminum plate specimens. One purpose of this investigation is to identify and characterize specific features of polar backscatter interrogation which enhance the ability of ultrasound to detect flaws in a stitched composite laminate. Another focus is to explore the feasibility of implementing medical linear array imaging technology as a viable ultrasonic-based nondestructive evaluation method to inspect and characterize bonded aluminum lap joints. As an approach to implementing quantitative ultrasonic inspection methods to both of these materials, we focus on the physics that underlies the detection of flaws in such materials.

49 CFR 178.1060 - Topple test.

Code of Federal Regulations, 2013 CFR

2013-10-01

... there may be no loss of the filling substance. However a slight discharge (e.g., from closures or stitch... Container design types must be filled to their maximum permissible gross mass, the load being evenly...

49 CFR 178.1060 - Topple test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... there may be no loss of the filling substance. However a slight discharge (e.g., from closures or stitch... Container design types must be filled to their maximum permissible gross mass, the load being evenly...

How Stitches Help Kids Heal

MedlinePlus

... cuts is a small sticky strip called a butterfly bandage. It keeps the edges of a shallow ... help. Different kinds of materials — sutures, glue, and butterflies — need different kinds of care. The doctor probably ...

Rabies

MedlinePlus

... and remove any foreign objects. Most of the time, stitches should not be used for animal bite wounds. If there is any risk of rabies, you will be given a series of a preventive vaccine . The vaccine is generally ...

KSC-2011-1485

NASA Image and Video Library

2011-02-18

CAPE CANAVERAL, Fla. -- Members of the Brevard Police and Fire Pipes and Drums kick off the "The National 9/11 Flag" stitching ceremony in the Debus Conference Facility at the Kennedy Space Center Visitor Complex in Florida. The contributions of NASA, Kennedy Space Center and the state of Florida were stitched into the fabric of the American Flag, which was recovered near ground zero following the World Trade Center attacks on Sept. 11, 2001. The "New York Says Thank You Foundation" is taking the flag on a cross-country journey to be restored to its original 13-stripe design using pieces of fabric from American flags destined for retirement in all 50 states. Once the flag is restored, it will become a permanent collection of the National September 11 Memorial Museum being built at the World Trade Center site. Photo credit: NASA/Kim Shiflett

KSC-2011-1489

NASA Image and Video Library

2011-02-18

CAPE CANAVERAL, Fla. -- Chief of Fire Training George Hoggard with NASA Kennedy Space Center Protective Services contributes stitches to the "National 9/11 Flag" during a ceremony in the Debus Conference Facility at the Kennedy Space Center Visitor Complex in Florida. The contributions of NASA, Kennedy Space Center and the state of Florida were stitched into the fabric of the American Flag, which was recovered near ground zero following the World Trade Center attacks on Sept. 11, 2001. The "New York Says Thank You Foundation" is taking the flag on a cross-country journey to be restored to its original 13-stripe design using pieces of fabric from American flags destined for retirement in all 50 states. Once the flag is restored, it will become a permanent collection of the National September 11 Memorial Museum being built at the World Trade Center site. Photo credit: NASA/Kim Shiflett

KSC-2011-1491

NASA Image and Video Library

2011-02-18

CAPE CANAVERAL, Fla. -- Kelvin Manning, associate director for Business Operations at NASA's Kennedy Space Center, contributes stitches to the "National 9/11 Flag" during a ceremony in the Debus Conference Facility at the Kennedy Space Center Visitor Complex in Florida. The contributions of NASA, Kennedy Space Center and the state of Florida were stitched into the fabric of the American Flag, which was recovered near ground zero following the World Trade Center attacks on Sept. 11, 2001. The "New York Says Thank You Foundation" is taking the flag on a cross-country journey to be restored to its original 13-stripe design using pieces of fabric from American flags destined for retirement in all 50 states. Once the flag is restored, it will become a permanent collection of the National September 11 Memorial Museum being built at the World Trade Center site. Photo credit: NASA/Kim Shiflett

KSC-2011-1490

NASA Image and Video Library

2011-02-18

CAPE CANAVERAL, Fla. -- Joe Dowdy, special operations manager at NASA's Kennedy Space Center, contributes stitches to the "National 9/11 Flag" during a ceremony in the Debus Conference Facility at the Kennedy Space Center Visitor Complex in Florida. The contributions of NASA, Kennedy Space Center and the state of Florida were stitched into the fabric of the American Flag, which was recovered near ground zero following the World Trade Center attacks on Sept. 11, 2001. The "New York Says Thank You Foundation" is taking the flag on a cross-country journey to be restored to its original 13-stripe design using pieces of fabric from American flags destined for retirement in all 50 states. Once the flag is restored, it will become a permanent collection of the National September 11 Memorial Museum being built at the World Trade Center site. Photo credit: NASA/Kim Shiflett

KSC-2011-1486

NASA Image and Video Library

2011-02-18

CAPE CANAVERAL, Fla. -- Members of the Brevard Police and Fire Pipes and Drums kick off the "The National 9/11 Flag" stitching ceremony in the Debus Conference Facility at the Kennedy Space Center Visitor Complex in Florida. The contributions of NASA, Kennedy Space Center and the state of Florida were stitched into the fabric of the American Flag, which was recovered near ground zero following the World Trade Center attacks on Sept. 11, 2001. The "New York Says Thank You Foundation" is taking the flag on a cross-country journey to be restored to its original 13-stripe design using pieces of fabric from American flags destined for retirement in all 50 states. Once the flag is restored, it will become a permanent collection of the National September 11 Memorial Museum being built at the World Trade Center site. Photo credit: NASA/Kim Shiflett

Data on kilometer scale production of stretchable conductive multifilaments enables knitting wearable strain sensing textiles.

PubMed

Seyedin, Shayan; Moradi, Sepehr; Singh, Charanpreet; Razal, Joselito M

2018-06-01

This data article contains analyzed data for the article "Continuous Production of Stretchable Conductive Multifilaments in Kilometer Scale Enables Facile Knitting of Wearable Strain Sensing Textiles" (Seyedin et al., 2018) [1]. Details of wet-spinning conditions to achieve scaled-up production of stretchable and conducting polyurethane/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PU/PEDOT:PSS) multifilaments are provided. The stress-strain curves for tensile and stretch-relaxation tests on the multifilament and different knitted textile structures (plain-knit, co-knit, co-knit-alternate, co-knit with conductive stitch, and plain with non-conductive stitch) are presented. It is shown that the PU/PEDOT:PSS multifilaments can also be knitted into fabrics that when worn on various body parts, such as knee, elbow, and finger, can monitor their various movements.

Subaperture metrology technologies extend capabilities in optics manufacturing

NASA Astrophysics Data System (ADS)

Tricard, Marc; Forbes, Greg; Murphy, Paul

2005-10-01

Subaperture polishing technologies have radically changed the landscape of precision optics manufacturing and enabled the production of higher precision optics with increasingly difficult figure requirements. However, metrology is a critical piece of the optics fabrication process, and the dependence on interferometry is especially acute for computer-controlled, deterministic finishing. Without accurate full-aperture metrology, figure correction using subaperture polishing technologies would not be possible. QED Technologies has developed the Subaperture Stitching Interferometer (SSI) that extends the effective aperture and dynamic range of a phase measuring interferometer. The SSI's novel developments in software and hardware improve the capacity and accuracy of traditional interferometers, overcoming many of the limitations previously faced. The SSI performs high-accuracy automated measurements of spheres, flats, and mild aspheres up to 200 mm in diameter by stitching subaperture data. The system combines a six-axis precision workstation, a commercial Fizeau interferometer of 4" or 6" aperture, and dedicated software. QED's software automates the measurement design, data acquisition, and mathematical reconstruction of the full-aperture phase map. The stitching algorithm incorporates a general framework for compensating several types of errors introduced by the interferometer and stage mechanics. These include positioning errors, viewing system distortion, the system reference wave error, etc. The SSI has been proven to deliver the accurate and flexible metrology that is vital to precision optics fabrication. This paper will briefly review the capabilities of the SSI as a production-ready, metrology system that enables costeffective manufacturing of precision optical surfaces.

Resin Film Infusion (RFI) Process Modeling for Large Transport Aircraft Wing Structures

NASA Technical Reports Server (NTRS)

Knott, Tamara W.; Loos, Alfred C.

2000-01-01

Resin film infusion (RFI) is a cost-effective method for fabricating stiffened aircraft wing structures. The RFI process lends itself to the use of near net shape textile preforms manufactured through a variety of automated textile processes such as knitting and braiding. Often, these advanced fiber architecture preforms have through-the-thickness stitching for improved damage tolerance and delamination resistance. The challenge presently facing RFI is to refine the process to ensure complete infiltration and cure of a geometrically complex shape preform with the high fiber volume fraction needed for structural applications. An accurate measurement of preform permeability is critical for successful modeling of the RFI resin infiltration process. Small changes in the permeability can result in very different infiltration behavior and times. Therefore, it is important to accurately measure the permeabilities of the textile preforms used in the RFI process. The objective of this investigation was to develop test methods that can be used to measure the compaction behavior and permeabilities of high fiber volume fraction, advanced fiber architecture textile preforms. These preforms are often highly compacted due to through-the-thickness stitching used to improve damage tolerance. Test fixtures were designed and fabricated and used to measure both transverse and in-plane permeabilities. The fixtures were used to measure the permeabilities of multiaxial warp knit and triaxial braided preforms at fiber volume fractions from 55% to 65%. In addition, the effects of stitching characteristics, thickness, and batch variability on permeability and compaction behavior were investigated.

Image Mosaicking Approach for a Double-Camera System in the GaoFen2 Optical Remote Sensing Satellite Based on the Big Virtual Camera.

PubMed

Cheng, Yufeng; Jin, Shuying; Wang, Mi; Zhu, Ying; Dong, Zhipeng

2017-06-20

The linear array push broom imaging mode is widely used for high resolution optical satellites (HROS). Using double-cameras attached by a high-rigidity support along with push broom imaging is one method to enlarge the field of view while ensuring high resolution. High accuracy image mosaicking is the key factor of the geometrical quality of complete stitched satellite imagery. This paper proposes a high accuracy image mosaicking approach based on the big virtual camera (BVC) in the double-camera system on the GaoFen2 optical remote sensing satellite (GF2). A big virtual camera can be built according to the rigorous imaging model of a single camera; then, each single image strip obtained by each TDI-CCD detector can be re-projected to the virtual detector of the big virtual camera coordinate system using forward-projection and backward-projection to obtain the corresponding single virtual image. After an on-orbit calibration and relative orientation, the complete final virtual image can be obtained by stitching the single virtual images together based on their coordinate information on the big virtual detector image plane. The paper subtly uses the concept of the big virtual camera to obtain a stitched image and the corresponding high accuracy rational function model (RFM) for concurrent post processing. Experiments verified that the proposed method can achieve seamless mosaicking while maintaining the geometric accuracy.

Photometric Calibration and Image Stitching for a Large Field of View Multi-Camera System

PubMed Central

Lu, Yu; Wang, Keyi; Fan, Gongshu

2016-01-01

A new compact large field of view (FOV) multi-camera system is introduced. The camera is based on seven tiny complementary metal-oxide-semiconductor sensor modules covering over 160° × 160° FOV. Although image stitching has been studied extensively, sensor and lens differences have not been considered in previous multi-camera devices. In this study, we have calibrated the photometric characteristics of the multi-camera device. Lenses were not mounted on the sensor in the process of radiometric response calibration to eliminate the influence of the focusing effect of uniform light from an integrating sphere. Linearity range of the radiometric response, non-linearity response characteristics, sensitivity, and dark current of the camera response function are presented. The R, G, and B channels have different responses for the same illuminance. Vignetting artifact patterns have been tested. The actual luminance of the object is retrieved by sensor calibration results, and is used to blend images to make panoramas reflect the objective luminance more objectively. This compensates for the limitation of stitching images that are more realistic only through the smoothing method. The dynamic range limitation of can be resolved by using multiple cameras that cover a large field of view instead of a single image sensor with a wide-angle lens. The dynamic range is expanded by 48-fold in this system. We can obtain seven images in one shot with this multi-camera system, at 13 frames per second. PMID:27077857

Stabilization of RNA hairpins using non-nucleotide linkers and circularization.

PubMed

Kiliszek, Agnieszka; Blaszczyk, Leszek; Kierzek, Ryszard; Rypniewski, Wojciech

2017-06-02

An RNA hairpin is an essential structural element of RNA. Hairpins play crucial roles in gene expression and intermolecular recognition but are also involved in the pathogenesis of some congenital diseases. Structural studies of the hairpin motifs are impeded by their thermodynamic instability, as they tend to unfold to form duplexes, especially at high concentrations required for crystallography or nuclear magnetic resonance spectroscopy. We have elaborated techniques to stabilize the RNA hairpins by linking the free ends of the RNA strand at the base of the hairpin stem. One method involves stilbene diether or hexaethylene glycol linkers and circularization by T4 RNA ligase. Another method uses click chemistry to stitch the RNA ends with a triazole linker. Both techniques are efficient and easy to perform. They should be useful in making stable, biologically relevant RNA constructs for structural studies. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

High throughput fabrication of large-area plasmonic color filters by soft-X-ray interference lithography.

PubMed

Sun, Libin; Hu, Xiaolin; Wu, Qingjun; Wang, Liansheng; Zhao, Jun; Yang, Shumin; Tai, Renzhong; Fecht, Hans-Jorg; Zhang, Dong-Xian; Wang, Li-Qiang; Jiang, Jian-Zhong

2016-08-22

Plasmonic color filters in mass production have been restricted from current fabrication technology, which impede their applications. Soft-X-ray interference lithography (XIL) has recently generated considerable interest as a newly developed technique for the production of periodic nano-structures with resolution theoretically below 4 nm. Here we ameliorate XIL by adding an order sorting aperture and designing the light path properly to achieve perfect-stitching nano-patterns and fast fabrication of large-area color filters. The fill factor of nanostructures prepared on ultrathin Ag films can largely affect the transmission minimum of plasmonic color filters. By changing the fill factor, the color can be controlled flexibly, improving the utilization efficiency of the mask in XIL simultaneously. The calculated data agree well with the experimental results. Finally, an underlying mechanism has been uncovered after systematically analyzing the localized surface plasmon polaritons (LSPPs) coupling in electric field distribution.

Stitching Codeable Circuits: High School Students' Learning About Circuitry and Coding with Electronic Textiles

NASA Astrophysics Data System (ADS)

Litts, Breanne K.; Kafai, Yasmin B.; Lui, Debora A.; Walker, Justice T.; Widman, Sari A.

2017-10-01

Learning about circuitry by connecting a battery, light bulb, and wires is a common activity in many science classrooms. In this paper, we expand students' learning about circuitry with electronic textiles, which use conductive thread instead of wires and sewable LEDs instead of lightbulbs, by integrating programming sensor inputs and light outputs and examining how the two domains interact. We implemented an electronic textiles unit with 23 high school students ages 16-17 years who learned how to craft and code circuits with the LilyPad Arduino, an electronic textile construction kit. Our analyses not only confirm significant increases in students' understanding of functional circuits but also showcase students' ability in designing and remixing program code for controlling circuits. In our discussion, we address opportunities and challenges of introducing codeable circuit design for integrating maker activities that include engineering and computing into classrooms.

MISR Toolkit

Atmospheric Science Data Center

2018-03-14

... which makes it very easy to extract and use MISR data sets. Reading a parameter requires the user to simply specify a file, grid, field, ... Automatically stitch, unpack and unscale MISR data while reading Performing coordinate conversions between lat/lon, SOM x/y, ...

Anti-reflux surgery - discharge

MedlinePlus

... can increase your activity and return to work. Wound Care Take care of your wound (incision): If sutures (stitches), staples, or glue were ... to close your skin, you may remove the wound dressings (bandages) and take a shower the day ...

Inguinal hernia repair

MedlinePlus

... through this weakened area. Description During surgery to repair the hernia, the bulging tissue is pushed back in. Your abdominal wall is strengthened and supported with sutures (stitches), and sometimes mesh. This repair can be done with open or laparoscopic surgery. ...

Mechanically and electrically robust metal-mask design for organic CMOS circuits

NASA Astrophysics Data System (ADS)

Shintani, Michihiro; Qin, Zhaoxing; Kuribara, Kazunori; Ogasahara, Yasuhiro; Hiromoto, Masayuki; Sato, Takashi

2018-04-01

The design of metal masks for fabricating organic CMOS circuits requires the consideration of not only the electrical property of the circuits, but also the mechanical strength of the masks. In this paper, we propose a new design flow for metal masks that realizes coanalysis of the mechanical and electrical properties and enables design exploration considering the trade-off between the two properties. As a case study, we apply a “stitching technique” to the mask design of a ring oscillator and explore the best design. With this technique, mask patterns are divided into separate parts using multiple mask layers to improve the mechanical strength at the cost of high resistance of the vias. By a numerical experiment, the design trade-off of the stitching technique is quantitatively analyzed, and it is demonstrated that the proposed flow is useful for the exploration of the designs of metal masks.

Structural Testing of a Stitched/Resin Film Infused Graphite-Epoxy Wing Box

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Bush, Harold G.

2001-01-01

The results of a series of tests conducted at the NASA Langley Research Center to evaluate the behavior of an all-composite full-scale wing box are presented. The wing box is representative of a section of a 220-passenger commercial transport aircraft wing box and was designed and constructed by The Boeing Company as part of the NASA Advanced Subsonics Technology (AST) program. The semi-span wing was fabricated from a graphite-epoxy material system with cover panels and spars held together using Kevlar stitches through the thickness. No mechanical fasteners were used to hold the stiffeners to the skin of the cover panels. Tests were conducted with and without low-speed impact damage, discrete source damage and repairs. Up-bending, down-bending and brake roll loading conditions were applied. The structure with non-visible impact damage carried 97% of Design Ultimate Load prior to failure through a lower cover panel access hole.

Application of Interface Technology in Nonlinear Analysis of a Stitched/RFI Composite Wing Stub Box

NASA Technical Reports Server (NTRS)

Wang, John T.; Ransom, Jonathan B.

1997-01-01

A recently developed interface technology was successfully employed in the geometrically nonlinear analysis of a full-scale stitched/RFI composite wing box loaded in bending. The technology allows mismatched finite element models to be joined in a variationally consistent manner and reduces the modeling complexity by eliminating transition meshing. In the analysis, local finite element models of nonlinearly deformed wide bays of the wing box are refined without the need for transition meshing to the surrounding coarse mesh. The COMET-AR finite element code, which has the interface technology capability, was used to perform the analyses. The COMET-AR analysis is compared to both a NASTRAN analysis and to experimental data. The interface technology solution is shown to be in good agreement with both. The viability of interface technology for coupled global/local analysis of large scale aircraft structures is demonstrated.

Development of Stitched, Braided and Woven Composite Structures in the ACT Program and at Langley Research Center

NASA Technical Reports Server (NTRS)

Dow, Marvin B.; Dexter, H. Benson

1997-01-01

Summary results are presented from the research conducted on woven, braided, knitted and stitched (textile) composites at the Langley Research Center and under the NASA Advanced Composites Technology (ACT) Program in the period from 1985 to 1997. The report also includes an annotated bibliography of 270 U.S. publications on textile composites (with their abstracts). Two major research areas are discussed: (1) the general research in textile composites performed throughout the period under the direction of the Langley Research Center and (2) the development of textile composite aircraft structures by industry under the NASA ACT Program. The annotated bibliography is organized in three subsections: (1) general textiles R&D under the auspices of Langley, (2) ACT Program development of textile structural components, and (3) textiles research by individuals and organizations not associated with the ACT Program. An author index is provided for the reports and documents.

Structural Response and Failure of a Full-Scale Stitched Graphite-Epoxy Wing

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Lovejoy, Andrew E.; Bush, Harold G.

2001-01-01

Analytical and experimental results of the test for an all-composite full-scale wing box are presented. The wing box is representative of a section of a 220-passenger commercial transport aircraft wing box and was designed and constructed by The Boeing Company as part of the NASA Advanced Subsonics Technology (AST) program. The semi-span wing was fabricated from a graphite-epoxy material system with cover panels and spars held together using Kevlar stitches through the thickness. No mechanical fasteners were used to hold the stiffeners to the skin of the cover panels. Tests were conducted with and without low-speed impact damage, discrete source damage and repairs. Up-bending down-bending and brake roll loading conditions were applied. The structure with nonvisible impact damage carried 97% of Design Ultimate Load prior to failure through a lower cover panel access hole. Finite element and experimental results agree for the global response of the structure.

Improved MRF spot characterization with QIS metrology

NASA Astrophysics Data System (ADS)

Westover, Sandi; Hall, Christopher; DeMarco, Michael

2013-09-01

Careful characterization of the removal function of sub-aperture polishing tools is critical for optimum polishing results. Magnetorheological finishing (MRF®) creates a polishing tool, or "spot", that is unique both for its locally high removal rate and high slope content. For a variety of reasons, which will be discussed, longer duration spots are beneficial to improving MRF performance, but longer spots yield higher slopes rendering them difficult to measure with adequate fidelity. QED's Interferometer for Stitching (QIS™) was designed to measure the high slope content inherent to non-null sub-aperture stitching interferometry of aspheres. Based on this unique capability the QIS was recently used to measure various MRF spots in an attempt to see if there was a corresponding improvement in MRF performance as a result of improved knowledge of these longer duration spots. The results of these tests will be presented and compared with those of a standard general purpose interferometer.

Stability of a dragged viscous thread: Onset of ``stitching'' in a fluid-mechanical ``sewing machine''

NASA Astrophysics Data System (ADS)

Ribe, Neil M.; Lister, John R.; Chiu-Webster, Sunny

2006-12-01

A thin thread of viscous fluid that falls on a moving belt acts like a fluid-mechanical "sewing machine," exhibiting a rich variety of "stitch" patterns including meanders, translated coiling, slanted loops, braiding, figures-of-eight, W-patterns, side kicks, and period-doubled patterns. Using a numerical linear stability analysis, we determine the critical belt speed and oscillation frequency of the first bifurcation, at which a steady dragged viscous thread becomes unstable to transverse oscillations or "meandering." The predictions of the stability analysis agree closely with the experimental measurements of Chiu-Webster and Lister [J. Fluid Mech. 569, 89 (2006)]. Moreover, the critical belt speed and onset frequency for meandering are nearly identical to the contact-point migration speed and angular frequency, respectively, of steady coiling of a viscous thread on a stationary surface, implying a remarkable degree of dynamical similarity between the two phenomena.

Onset of `stitching' in the fluid mechanical `sewing machine'

NASA Astrophysics Data System (ADS)

Ribe, Neil; Lister, John; Chiu-Webster, Sunny

2006-11-01

A thin thread of viscous fluid that falls on a moving belt acts like a fluid mechanical `sewing machine', exhibiting a rich variety of `stitch' patterns including meanders, side kicks, slanted loops, braiding, figures-of-eight, W-patterns, and period-doubled patterns (Chiu-Webster and Lister, J. Fluid Mech., in press). Using a numerical linear stability analysis based on asymptotic `slender thread' theory, we determine the critical belt speed and frequency of the first bifurcation, at which a steady dragged viscous thread becomes unstable to sideways oscillations (`meanders'). The predictions of the stability analysis agree closely with experimental measurements. Moreover, we find that the critical belt speed and frequency for meandering are nearly identical to the contact point migration speed and the frequency, respectively, of steady coiling of a viscous thread on a stationary surface, implying a remarkable degree of dynamical similarity between the two phenomena.

Color sensitivity of the multi-exposure HDR imaging process

NASA Astrophysics Data System (ADS)

Lenseigne, Boris; Jacobs, Valéry Ann; Withouck, Martijn; Hanselaer, Peter; Jonker, Pieter P.

2013-04-01

Multi-exposure high dynamic range(HDR) imaging builds HDR radiance maps by stitching together different views of a same scene with varying exposures. Practically, this process involves converting raw sensor data into low dynamic range (LDR) images, estimate the camera response curves, and use them in order to recover the irradiance for every pixel. During the export, applying white balance settings and image stitching, which both have an influence on the color balance in the final image. In this paper, we use a calibrated quasi-monochromatic light source, an integrating sphere, and a spectrograph in order to evaluate and compare the average spectral response of the image sensor. We finally draw some conclusion about the color consistency of HDR imaging and the additional steps necessary to use multi-exposure HDR imaging as a tool to measure the physical quantities such as radiance and luminance.

Evaluation of the Structural Response and Failure of a Full-Scale Stitched Graphite-Epoxy Wing

NASA Astrophysics Data System (ADS)

Jegley, Dawn C.; Bush, Harold G.; Lovejoy, Andrew E.

2001-01-01

Analytical and experimental results for an all-composite full-scale wing box are presented. The wing box is representative of a section of a 220-passenger commercial transport aircraft wing box and was designed and constructed by The Boeing Company as part of the NASA Advanced Subsonics Technology (AST) program. The semi-span wing was fabricated from a graphite-epoxy material system with cover panels and spars held together using Kevlar stitches through the thickness. No mechanical fasteners were used to hold the stiffeners to the skin of the cover panels. Tests were conducted with and without low-speed impact damage, discrete source damage and repairs. Upbending, down-bending and brake roll loading conditions were applied. The structure with nonvisible impact damage carried 97% of Design Ultimate Load prior to failure through a lower cover panel access hole. Finite element and experimental results agree for the global response of the structure.

Magnetic Resonance Imaging of Surgical Implants Made from Weak Magnetic Materials

NASA Astrophysics Data System (ADS)

Gogola, D.; Krafčík, A.; Štrbák, O.; Frollo, I.

2013-08-01

Materials with high magnetic susceptibility cause local inhomogeneities in the main field of the magnetic resonance (MR) tomograph. These inhomogeneities lead to loss of phase coherence, and thus to a rapid loss of signal in the image. In our research we investigated inhomogeneous field of magnetic implants such as magnetic fibers, designed for inner suture during surgery. The magnetic field inhomogeneities were studied at low magnetic planar phantom, which was made from four thin strips of magnetic tape, arranged grid-wise. We optimized the properties of imaging sequences with the aim to find the best setup for magnetic fiber visualization. These fibers can be potentially exploited in surgery for internal stitches. Stitches can be visualized by the magnetic resonance imaging (MRI) method after surgery. This study shows that the imaging of magnetic implants is possible by using the low field MRI systems, without the use of complicated post processing techniques (e.g., IDEAL).

Test methods for textile composites

NASA Technical Reports Server (NTRS)

Minguet, Pierre J.; Fedro, Mark J.; Gunther, Christian K.

1994-01-01

Various test methods commonly used for measuring properties of tape laminate composites were evaluated to determine their suitability for the testing of textile composites. Three different types of textile composites were utilized in this investigation: two-dimensional (2-D) triaxial braids, stitched uniweave fabric, and three-dimensional (3-D) interlock woven fabric. Four 2-D braid architectures, five stitched laminates, and six 3-D woven architectures were tested. All preforms used AS4 fibers and were resin-transfer-molded with Shell RSL-1895 epoxy resin. Ten categories of material properties were investigated: tension, open-hole tension, compression, open-hole compression, in-plane shear, filled-hole tension, bolt bearing, interlaminar tension, interlaminar shear, and interlaminar fracture toughness. Different test methods and specimen sizes were considered for each category of test. Strength and stiffness properties obtained with each of these methods are documented in this report for all the material systems mentioned above.

KSC-2011-1492

NASA Image and Video Library

2011-02-18

CAPE CANAVERAL, Fla. – Deputy Fire Chief Rick Anderson, left, Chief of Fire Training George Hoggard, and Assistant Chief of Fire Training David Seymour with NASA Kennedy Space Center Protective Services participated in the "National 9/11 Flag" stitching ceremony in the Debus Conference Facility at the Kennedy Space Center Visitor Complex in Florida. The contributions of NASA, Kennedy Space Center and the state of Florida were stitched into the fabric of the American Flag, which was recovered near ground zero following the World Trade Center attacks on Sept. 11, 2001. The "New York Says Thank You Foundation" is taking the flag on a cross-country journey to be restored to its original 13-stripe design using pieces of fabric from American flags destined for retirement in all 50 states. Once the flag is restored, it will become a permanent collection of the National September 11 Memorial Museum being built at the World Trade Center site. Photo credit: NASA/Kim Shiflett

Pigment dispersion syndrome associated with intraocular lens implantation: a new surgical technique.

PubMed

Canut Jordana, M Isabel; Pérez Formigó, Daniel; Abreu González, Rodrigo; Nadal Reus, Jeroni

2010-11-11

We report the case of a myopic patient who, after intraocular lens transplant in the posterior chamber, suffered elevated intraocular pressure due to pigment dispersion, with recurrent episodes of blurred vision. The patient was treated with a new surgical technique that can avoid potential iridolenticular contact. Complete ophthalmologic examination and optical coherence tomography (OCT) of the anterior segment were performed. Contact between the pigmentary epithelium and the iris with an intraocular lens was revealed by utrasound biomicroscopy and OCT. In this case, Nd:YAG laser iridotomy and laser iridoplasty were not effective for iridolenticular separation and control of the pigment dispersion. We propose a new technique: stitches on the surface of the iris to obtain good iridolenticular separation and good intraocular pressure control. Stitches on the iris surface should be considered as optional therapy in pigmentary glaucoma secondary to intraocular lens implantation. This surgical technique can avoid potential iridolenticular contacts more definitively.

Non-overlap subaperture interferometric testing for large optics

NASA Astrophysics Data System (ADS)

Wu, Xin; Yu, Yingjie; Zeng, Wenhan; Qi, Te; Chen, Mingyi; Jiang, Xiangqian

2017-08-01

It has been shown that the number of subapertures and the amount of overlap has a significant influence on the stitching accuracy. In this paper, a non-overlap subaperture interferometric testing method (NOSAI) is proposed to inspect large optical components. This method would greatly reduce the number of subapertures and the influence of environmental interference while maintaining the accuracy of reconstruction. A general subaperture distribution pattern of NOSAI is also proposed for the large rectangle surface. The square Zernike polynomial is employed to fit such wavefront. The effect of the minimum fitting terms on the accuracy of NOSAI and the sensitivities of NOSAI to subaperture's alignment error, power systematic error, and random noise are discussed. Experimental results validate the feasibility and accuracy of the proposed NOSAI in comparison with wavefront obtained by a large aperture interferometer and stitching surface by multi-aperture overlap-scanning technique (MAOST).

Quantitative nanoscopy: Tackling sampling limitations in (S)TEM imaging of polymers and composites.

PubMed

Gnanasekaran, Karthikeyan; Snel, Roderick; de With, Gijsbertus; Friedrich, Heiner

2016-01-01

Sampling limitations in electron microscopy questions whether the analysis of a bulk material is representative, especially while analyzing hierarchical morphologies that extend over multiple length scales. We tackled this problem by automatically acquiring a large series of partially overlapping (S)TEM images with sufficient resolution, subsequently stitched together to generate a large-area map using an in-house developed acquisition toolbox (TU/e Acquisition ToolBox) and stitching module (TU/e Stitcher). In addition, we show that quantitative image analysis of the large scale maps provides representative information that can be related to the synthesis and process conditions of hierarchical materials, which moves electron microscopy analysis towards becoming a bulk characterization tool. We demonstrate the power of such an analysis by examining two different multi-phase materials that are structured over multiple length scales. Copyright © 2015 Elsevier B.V. All rights reserved.

An Integrative Object-Based Image Analysis Workflow for Uav Images

NASA Astrophysics Data System (ADS)

Yu, Huai; Yan, Tianheng; Yang, Wen; Zheng, Hong

2016-06-01

In this work, we propose an integrative framework to process UAV images. The overall process can be viewed as a pipeline consisting of the geometric and radiometric corrections, subsequent panoramic mosaicking and hierarchical image segmentation for later Object Based Image Analysis (OBIA). More precisely, we first introduce an efficient image stitching algorithm after the geometric calibration and radiometric correction, which employs a fast feature extraction and matching by combining the local difference binary descriptor and the local sensitive hashing. We then use a Binary Partition Tree (BPT) representation for the large mosaicked panoramic image, which starts by the definition of an initial partition obtained by an over-segmentation algorithm, i.e., the simple linear iterative clustering (SLIC). Finally, we build an object-based hierarchical structure by fully considering the spectral and spatial information of the super-pixels and their topological relationships. Moreover, an optimal segmentation is obtained by filtering the complex hierarchies into simpler ones according to some criterions, such as the uniform homogeneity and semantic consistency. Experimental results on processing the post-seismic UAV images of the 2013 Ya'an earthquake demonstrate the effectiveness and efficiency of our proposed method.

Diversity and Innovation for Geosciences (dig) Texas Earth and Space Science Instructional Blueprints

NASA Astrophysics Data System (ADS)

Ellins, K. K.; Bohls-Graham, E.; Riggs, E. M.; Serpa, L. F.; Jacobs, B. E.; Martinez, A. O.; Fox, S.; Kent, M.; Stocks, E.; Pennington, D. D.

2014-12-01

The NSF-sponsored DIG Texas Instructional Blueprint project supports the development of online instructional blueprints for a yearlong high school-level Earth science course. Each blueprint stitches together three-week units that contain curated educational resources aligned with the Texas state standards for Earth and Space Science and the Earth Science Literacy Principles. Units focus on specific geoscience content, place-based concerns, features or ideas, or other specific conceptual threads. Five regional teams composed of geoscientists, pedagogy specialists, and practicing science teachers chose unit themes and resources for twenty-two units during three workshops. In summer 2014 three Education Interns (Earth science teachers) spent six weeks refining the content of the units and aligning them with the Next Generation Science Standards. They also assembled units into example blueprints. The cross-disciplinary collaboration among blueprint team members allowed them to develop knowledge in new areas and to share their own discipline-based knowledge and perspectives. Team members and Education Interns learned where to find and how to evaluate high quality geoscience educational resources, using a web-based resource review tool developed by the Science Education Resource Center (SERC). SERC is the repository for the DIG Texas blueprint web pages. Work is underway to develop automated tools to allow educators to compile resources into customized instructional blueprints by reshuffling units within an existing blueprint, by mixing units from other blueprints, or creating new units and blueprints. These innovations will enhance the use of the units by secondary Earth science educators beyond Texas. This presentation provides an overview of the project, shows examples of blueprints and units, reports on the preliminary results of classroom implementation by Earth science teachers, and considers challenges encountered in developing and testing the blueprints. The project is a collaboration between The University of Texas at Austin, The University of Texas at El Paso, and Texas A&M University, all of which participate in the DIG Texas alliance. Website:serc.carleton.edu/dig_blueprints/index.html

Comparative effect of topical silicone gel and topical tretinoin cream for the prevention of hypertrophic scar and keloid formation and the improvement of scars.

PubMed

Kwon, S Y; Park, S D; Park, K

2014-08-01

Numerous modalities have been used to treat keloids and hypertrophic scars; however, optimal treatment has not yet been established. Therefore, prevention is the mainstay. Recently, silicone gel and tretinoin cream have been shown to be useful for the prevention of hypertrophic scars and keloids. However, there has been no comparative study of the two topical agents thus far. To determine and compare the effectiveness of silicone gel and tretinoin cream for the prevention of hypertrophic scars and keloids resulting from postoperative wounds and for scar improvement. This study included 26 patients with 44 different wounds. The postoperative wounds were divided into two treatment groups and one control group. The patients in the first and second treatment group applied silicone gel and tretinoin cream, respectively, twice a day on their wounds after their stitches were removed. In contrast, the control group patients did not apply anything. We used the Modified Vancouver Scar Scale to quantitatively examine the effectiveness of silicone gel and tretinoin cream just after stitches removal, and at 4, 8, 12 and 24 weeks after removal of the stitches. The silicone gel and tretinoin cream effectively prevented hypertrophic scars and keloids and improved scar effects in the two treatment groups compared with those in the control group. However, no significant difference was noted between the two treatment groups. To prevent hypertrophic scars and keloids and improve scars after surgery, application of a silicone gel or a tretinoin cream to the wounds is needed. © 2013 European Academy of Dermatology and Venereology.

Multiple-aperture optical design for micro-level cameras using 3D-printing method

NASA Astrophysics Data System (ADS)

Peng, Wei-Jei; Hsu, Wei-Yao; Cheng, Yuan-Chieh; Lin, Wen-Lung; Yu, Zong-Ru; Chou, Hsiao-Yu; Chen, Fong-Zhi; Fu, Chien-Chung; Wu, Chong-Syuan; Huang, Chao-Tsung

2018-02-01

The design of the ultra miniaturized camera using 3D-printing technology directly printed on to the complementary metal-oxide semiconductor (CMOS) imaging sensor is presented in this paper. The 3D printed micro-optics is manufactured using the femtosecond two-photon direct laser writing, and the figure error which could achieve submicron accuracy is suitable for the optical system. Because the size of the micro-level camera is approximately several hundreds of micrometers, the resolution is reduced much and highly limited by the Nyquist frequency of the pixel pitch. For improving the reduced resolution, one single-lens can be replaced by multiple-aperture lenses with dissimilar field of view (FOV), and then stitching sub-images with different FOV can achieve a high resolution within the central region of the image. The reason is that the angular resolution of the lens with smaller FOV is higher than that with larger FOV, and then the angular resolution of the central area can be several times than that of the outer area after stitching. For the same image circle, the image quality of the central area of the multi-lens system is significantly superior to that of a single-lens. The foveated image using stitching FOV breaks the limitation of the resolution for the ultra miniaturized imaging system, and then it can be applied such as biomedical endoscopy, optical sensing, and machine vision, et al. In this study, the ultra miniaturized camera with multi-aperture optics is designed and simulated for the optimum optical performance.

Laser welding in penetrating keratoplasty and cataract surgery of pediatric patients: early results

NASA Astrophysics Data System (ADS)

Rossi, Francesca; Pini, Roberto; Menabuoni, Luca; Malandrini, Alex; Canovetti, Annalisa; Lenzetti, Ivo; Capozzi, Paolo; Valente, Paola; Buzzonetti, Luca

2013-03-01

Diode laser welding of ocular tissues is a procedure that enables minimally invasive closure of a corneal wound. This procedure is based on a photothermal effect: a water solution of Indocyanine Green (ICG) is inserted in the surgical wound, in order to stain the corneal tissue walls. The stained tissue is then irradiated with a low power infrared diode laser, delivering laser light through a 300-μm core diameter optical fiber. This procedure enables an immediate closure of the wounds: it is thus possible to reduce or to substitute the use of surgical threads. This is of particular interest in children, because the immediate closure improves refractive outcome and anti-amblyopic effect; moreover this procedure avoids several general anaesthesia for suture management. In this work, we present the first use of diode laser welding procedure in paediatric patients. 5 selected patients underwent cataract surgery (Group 1), while 4 underwent fs-laserassisted penetrating keratoplasty (Group 2). In Group 1 the conventional surgery procedure was performed, while no stitches were used for the closure of the surgical wounds: these were laser welded and immediately closed. In Group 2 the donor button was sutured upon the recipient by 8 single stitches, instead of 16 single stitches or a running suture. The laser welding procedure was performed in order to join the donor tissue to the recipient bed. Objective observations in the follow up study evidenced a perfect adhesion of the laser welded tissues, no collateral effects and an optimal restoration of the treated tissues.

Development of Textile Reinforced Composites for Aircraft Structures

NASA Technical Reports Server (NTRS)

Dexter, H. Benson

1998-01-01

NASA has been a leader in development of composite materials for aircraft applications during the past 25 years. In the early 1980's NASA and others conducted research to improve damage tolerance of composite structures through the use of toughened resins but these resins were not cost-effective. The aircraft industry wanted affordable, robust structures that could withstand the rigors of flight service with minimal damage. The cost and damage tolerance barriers of conventional laminated composites led NASA to focus on new concepts in composites which would incorporate the automated manufacturing methods of the textiles industry and which would incorporate through-the-thickness reinforcements. The NASA Advanced Composites Technology (ACT) Program provided the resources to extensively investigate the application of textile processes to next generation aircraft wing and fuselage structures. This paper discusses advanced textile material forms that have been developed, innovative machine concepts and key technology advancements required for future application of textile reinforced composites in commercial transport aircraft. Multiaxial warp knitting, triaxial braiding and through-the-thickness stitching are the three textile processes that have surfaced as the most promising for further development. Textile reinforced composite structural elements that have been developed in the NASA ACT Program are discussed. Included are braided fuselage frames and window-belt reinforcements, woven/stitched lower fuselage side panels, stitched multiaxial warp knit wing skins, and braided wing stiffeners. In addition, low-cost processing concepts such as resin transfer molding (RTM), resin film infusion (RFI), and vacuum-assisted resin transfer molding (VARTM) are discussed. Process modeling concepts to predict resin flow and cure in textile preforms are also discussed.

Incorporating the whole-mount prostate histology reconstruction program Histostitcher into the extensible imaging platform (XIP) framework

NASA Astrophysics Data System (ADS)

Toth, Robert; Chappelow, Jonathan; Vetter, Christoph; Kutter, Oliver; Russ, Christoph; Feldman, Michael; Tomaszewski, John; Shih, Natalie; Madabhushi, Anant

2012-03-01

There is a need for identifying quantitative imaging (e.g. MRI) signatures for prostate cancer (CaP), so that computer-aided diagnostic methods can be trained to detect disease extent in vivo. Determining CaP extent on in vivo MRI is difficult to do; however, with the availability of ex vivo surgical whole mount histological sections (WMHS) for CaP patients undergoing radical prostatectomy, co-registration methods can be applied to align and map disease extent onto pre-operative MR imaging from the post-operative histology. Yet obtaining digitized images of WHMS for co-registration with the pre-operative MRI is cumbersome since (a) most digital slide scanners are unable to accommodate the entire section, and (b) significant technical expertise is required for whole mount slide preparation. Consequently, most centers opt to construct quartered sections of each histology slice. Prior to co-registration with MRI, however, these quartered sections need to be digitally stitched together to reconstitute a digital, pseudo WMHS. Histostitcheris an interactive software program that uses semi-automatic registration tools to digitally stitch quartered sections into pseudo WMHS. Histostitcherwas originally developed using the GUI tools provided by the Matlab programming interface, but the clinical use was limited due to the inefficiency of the interface. The limitations of the Matlab based GUI include (a) an inability to edit the fiducials, (b) the rendering being extremely slow, and (c) lack of interactive and rapid visualization tools. In this work, Histostitcherhas been integrated into the eXtensible Imaging Platform (XIP TM ) framework (a set of libraries containing functionalities for analyzing and visualizing medical image data). XIP TM lends the stitching tool much greater flexibility and functionality by (a) allowing interactive and seamless navigation through the full resolution histology images, (b) the ability to easily add, edit, or remove fiducials and annotations in order to register the quadrants and map the disease extent. In this work, we showcase examples of digital stitching of quartered histological sections into pseudo-WHMS using Histostitcher via the new XIP TM interface. This tool will be particularly useful in clinical trials and large cohort studies where a quick, interactive way of digitally reconstructing pseudo WMHS is required.

Delayed Wound Healing in Heat Stable Antigen (HSA/CD24)-Deficient Mice

PubMed Central

Shapira, Shiran; Ben-Amotz, Oded; Sher, Osnat; Kazanov, Dina; Mashiah, Jacob; Kraus, Sarah; Gur, Eyal; Arber, Nadir

2015-01-01

Background Healthy individuals rarely have problems with wound healing. Most skin lesions heal rapidly and efficiently within one to two weeks. However, many medical and surgical complications can be attributed to deficiencies in wound repair. Open wounds have lost the barrier that protects tissues from bacterial invasion and allows the escape of vital fluids. Without expeditious healing, infections become more frequent. The CD24 gene encodes a heavily-glycosylated cell surface protein anchored to the membrane by phosphatidylinositol. CD24 plays an important role in the adaptive immune response and controls an important genetic checkpoint for homeostasis and autoimmune diseases in both mice and humans. We have previously shown that overexpression of CD24 results in increased proliferation and migration rates. Aim To examine the role of CD24 in the wound healing process. Methods An excisional model of wound healing was used and delayed wound healing was studied in genetically modified heat stable antigen (HSA/CD24)-deficient mice (HSA -/-) compared to wild-type (WT) mice. Results Large full-thickness skin wounds, excised on the back of mice, exhibited a significant delay in the formation of granulation tissue, and in wound closure when compared to their WTHSA +/+ littermates. Wounds were histologically analyzed and scored, based on the degree of cellular invasion, granulation tissue formation, vascularity, and re-epithelialization. Additionally, in stitched wounds, the HSA -/- mice failed to maintain their stitches; they did not hold and fell already 24 hours, revealing erythematous wound fields. Re-expression of HSA, delivered by lentivirus, restored the normal healing phenotype, within 24 hours post-injury, and even improved the healing in WT, and in BalbC mice. Conclusions Delayed wound-healing in the absence of HSA/CD24 suggests that CD24 plays an important role in this process. Increased expression of CD24, even in the normal state, may be used to enhance wound repair. PMID:26440795

Delayed Wound Healing in Heat Stable Antigen (HSA/CD24)-Deficient Mice.

PubMed

Shapira, Shiran; Ben-Amotz, Oded; Sher, Osnat; Kazanov, Dina; Mashiah, Jacob; Kraus, Sarah; Gur, Eyal; Arber, Nadir

2015-01-01

Healthy individuals rarely have problems with wound healing. Most skin lesions heal rapidly and efficiently within one to two weeks. However, many medical and surgical complications can be attributed to deficiencies in wound repair. Open wounds have lost the barrier that protects tissues from bacterial invasion and allows the escape of vital fluids. Without expeditious healing, infections become more frequent. The CD24 gene encodes a heavily-glycosylated cell surface protein anchored to the membrane by phosphatidylinositol. CD24 plays an important role in the adaptive immune response and controls an important genetic checkpoint for homeostasis and autoimmune diseases in both mice and humans. We have previously shown that overexpression of CD24 results in increased proliferation and migration rates. To examine the role of CD24 in the wound healing process. An excisional model of wound healing was used and delayed wound healing was studied in genetically modified heat stable antigen (HSA/CD24)-deficient mice (HSA-/-) compared to wild-type (WT) mice. Large full-thickness skin wounds, excised on the back of mice, exhibited a significant delay in the formation of granulation tissue, and in wound closure when compared to their WTHSA+/+ littermates. Wounds were histologically analyzed and scored, based on the degree of cellular invasion, granulation tissue formation, vascularity, and re-epithelialization. Additionally, in stitched wounds, the HSA-/- mice failed to maintain their stitches; they did not hold and fell already 24 hours, revealing erythematous wound fields. Re-expression of HSA, delivered by lentivirus, restored the normal healing phenotype, within 24 hours post-injury, and even improved the healing in WT, and in BalbC mice. Delayed wound-healing in the absence of HSA/CD24 suggests that CD24 plays an important role in this process. Increased expression of CD24, even in the normal state, may be used to enhance wound repair.

Interconnect mechanisms in microelectronic packaging

NASA Astrophysics Data System (ADS)

Roma, Maria Penafrancia C.

Global economic, environmental and market developments caused major impact in the microelectronics industry. Astronomical rise of gold metal prices over the last decade shifted the use of copper and silver alloys as bonding wires. Environmental legislation on the restriction of the use of Pb launched worldwide search for lead-free solders and platings. Finally, electrical and digital uses demanded smaller, faster and cheaper devices. Ultra-fine pitch bonding, decreasing bond wire sizes and hard to bond substrates have put the once-robust stitch bond in the center of reliability issues due to stitch bond lift or open wires .Unlike the ball bond, stitch bonding does not lead to intermetallic compound formation but adhesion is dependent on mechanical deformation, interdiffusion, solid solution formation, void formation and mechanical interlocking depending on the wire material, bond configuration, substrate type , thickness and surface condition. Using Au standoff stitch bonds on NiPdAu plated substrates eliminated stitch bond lift even when the Au and Pd layers are reduced. Using the Matano-Boltzmann analysis on a STEM (Scanning Transmission Analysis) concentration profile the interdiffusion coefficient is measured to be 10-16 cm 2/s. Wire pull strength data showed that the wire pull strength is 0.062N and increases upon stress testing. Meanwhile, coating the Cu wire with Pd, not only increases oxidation resistance but also improved adhesion due to the formation of a unique interfacial adhesion layers. Adhesion strength as measured by pull showed the Cu wire bonded to Ag plated Cu substrate (0.132N) to be stronger than the Au wire bonded on the same substrate (0.124N). Ag stitch bonded to Au is predicted to be strong but surface modification made the adhesion stronger. However, on the Ag ball bonded to Al showed multiple IMC formation with unique morphology exposed by ion milling and backscattered scanning electron microscopy. Adding alloying elements in the Ag wire alloy showed differences in adhesion strength and IMC formation. Bond strength by wire pull testing showed the 95Ag alloy with higher values while shear bond testing showed the 88Ag higher bond strength. Use of Cu pillars in flip chips and eutectic bonding in wafer level chip scale packages are direct consequences of diminishing interconnect dimension as a result of the drive for miniaturization. The combination of Cu-Sn interdiffusion, Kirkendall mechanism and heterogeneous vacancy precipitation are the main causes of IMC and void formation in Cu pillar - Sn solder - Cu lead frame sandwich structure. However, adding a Ni barrier agent showed less porous IMC layer as well as void formation as a result of the modified Cu and Sn movement well as the void formation. Direct die to die bonding using Al-Ge eutectic bonds is necessary when 3D integration is needed to reduce the footprint of a package. Hermeticity and adhesion strength are a function of the Al/Ge thickness ratio, bonding pressure, temperature and time. Scanning Electron Microscope (SEM) and Focused Ion Beam (FIB) allowed imaging of interfacial microstructures, porosity, grain morphology while Scanning Transmission Electron microscope (STEM) provided diffusion profile and confirmed interdiffusion. Ion polishing technique provided information on porosity and when imaged using backscattered mode, grain structure confirmed mechanical deformation of the bonds. Measurements of the interfacial bond strength are made by wire pull tests and ball shear tests based on existing industry standard tests. However, for the Al-Ge eutectic bonds, no standard strength is available so a test is developed using the stud pull test method using the Dage 4000 Plus to yield consistent results. Adhesion strengths of 30-40 MPa are found for eutectic bonded packages however, as low as 20MPa was measured in low temperature bonded areas.

Performance of resin transfer molded multiaxial warp knit composites

NASA Technical Reports Server (NTRS)

Dexter, H. Benson; Hasko, Gregory H.

1993-01-01

Composite materials that are subjected to complex loads have traditionally been fabricated with multidirectionally oriented prepreg tape materials. Some of the problems associated with this type of construction include low delamination resistance, poor out-of-plane strength, and labor intensive fabrication processes. Textile reinforced composites with through-the-thickness reinforcement have the potential to solve some of these problems. Recently, a relatively new class of noncrimp fabrics designated as multiaxial warp knits have been developed to minimize some of the high cost and damage tolerance concerns. Multiple stacks of warp knit fabrics can be knitted or stitched together to reduce layup labor cost. The through-the-thickness reinforcement can provide significant improvements in damage tolerance and out-of-plane strength. Multilayer knitted/stitched preforms, in conjunction with resin transfer molding (RTM), offer potential for significant cost savings in fabrication of primary aircraft structures. The objectives of this investigation were to conduct RTM processing studies and to characterize the mechanical behavior of composites reinforced with three multiaxial warp knit fabrics. The three fabrics investigated were produced by Hexcel and Milliken in the United States, and Saerbeck in Germany. Two resin systems, British Petroleum E9O5L and 3M PR 500, were characterized for RTM processing. The performance of Hexcel and Milliken quasi-isotropic knitted fabrics are compared to conventional prepreg tape laminates. The performance of the Saerbeck fabric is compared to uniweave wing skin layups being investigated by Douglas Aircraft Company in the NASA Advanced Composites Technology (ACT) program. Tests conducted include tension, open hole tension, compression, open hole compression, and compression after impact. The effects of fabric defects, such as misaligned fibers and gaps between tows, on material performance are also discussed. Estimated material and labor cost savings are projected for the Saerbeck fabric as compared to uniweave fabric currently being used by Douglas in the NASA ACT wing development program.

Transit spectroscopy with JWST: Systematics, starspots and stitching

NASA Astrophysics Data System (ADS)

Barstow, Joanna K.; Aigrain, Suzanne; Irwin, Patrick; Kendrew, Sarah; Fletcher, Leigh N.

2014-11-01

We explore the capabilities of JWST to obtain transit and eclipse spectra of a variety of exoplanets to provide constraints on their atmospheric properties, starting with hot Jupiters and Neptunes. We use the NEMESIS spectral modelling and inversion tool (Irwin et al. 2008) to calculate synthetic spectra for a range of exoplanet types from simple atmospheric models. Using a similar approach to Barstow et al. (2013), we add estimated noise levels to the synthetics before inverting the noisy spectra to check whether we accurately recover the input atmospheric state. The 5 - 12 μm MIRI LRS instrument on JWST ( 100) probes an important part of the infrared spectrum, especially for thermal emission; since a secondary eclipse spectrum relies on the contrast between the exoplanet and its host star, the signal is maximised at longer wavelengths. However, the spectral coverage of the LRS is insufficient to break degeneracies between temperature and composition without some constraint from other instruments. The ideal scenario would be to stitch together observations from NIRSpec ( 100, 0.6 - 5 μm), MIRI LRS, and MIRI MRS (integral field unit providing 3000 spectra across 12 gratings between 5 and 27 μm) to form a complete spectrum with broad wavelength coverage, which would enable the temperature structure and atmospheric composition to be uniquely retrieved. This means that it is necessary to consider in our analysis systematic offsets between parts of the spectrum obtained with different instruments. These offsets may have an astrophysical origin - for example due to stellar activity or temporal variability of the planet itself - or they may be instrumental effects. We explore the influence of these noise sources on our ability to accurately retrieve the true atmospheric state from transit and eclipse spectra. We can simultaneously retrieve temperature structure and H2O, CO2, and CH4 abundances of a hot Jupiter orbiting a sun-like star at 250 parsecs if a single eclipse each is observed with NIRSpec and MIRI LRS.

100. COBBLER SHOP AFT LOOKING FORWARD VISIBLE ARE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

100. COBBLER SHOP - AFT LOOKING FORWARD - VISIBLE ARE THE FINISHING MACHINE, DAVIS STITCHING MACHINE, SINGER SEWING MACHINE FROM TAILOR SHOP, STORAGE SHELVES, WORK BENCH AND SHOE TREE STAND. - U.S.S. HORNET, Puget Sound Naval Shipyard, Sinclair Inlet, Bremerton, Kitsap County, WA

Monte Carlo analysis for the determination of the conic constant of an aspheric micro lens based on a scanning white light interferometric measurement

NASA Astrophysics Data System (ADS)

Gugsa, Solomon A.; Davies, Angela

2005-08-01

Characterizing an aspheric micro lens is critical for understanding the performance and providing feedback to the manufacturing. We describe a method to find the best-fit conic of an aspheric micro lens using a least squares minimization and Monte Carlo analysis. Our analysis is based on scanning white light interferometry measurements, and we compare the standard rapid technique where a single measurement is taken of the apex of the lens to the more time-consuming stitching technique where more surface area is measured. Both are corrected for tip/tilt based on a planar fit to the substrate. Four major parameters and their uncertainties are estimated from the measurement and a chi-square minimization is carried out to determine the best-fit conic constant. The four parameters are the base radius of curvature, the aperture of the lens, the lens center, and the sag of the lens. A probability distribution is chosen for each of the four parameters based on the measurement uncertainties and a Monte Carlo process is used to iterate the minimization process. Eleven measurements were taken and data is also chosen randomly from the group during the Monte Carlo simulation to capture the measurement repeatability. A distribution of best-fit conic constants results, where the mean is a good estimate of the best-fit conic and the distribution width represents the combined measurement uncertainty. We also compare the Monte Carlo process for the stitched data and the not stitched data. Our analysis allows us to analyze the residual surface error in terms of Zernike polynomials and determine uncertainty estimates for each coefficient.

Influence of suture on peripheral nerve regeneration and collagen production at the site of neurorrhaphy: an experimental study.

PubMed

Martins, Roberto Sergio; Teodoro, Walcy Rosolio; Simplicio, Hougelle; Capellozi, Vera Luiza; Siqueira, Mario Gilberto; Yoshinari, Natalino Hajime; Pereira, José Pindaro; Teixeira, Manoel Jacobsen

2011-03-01

Restoration of nerve continuity and effective maintenance of coaptation are considered fundamental principles of end-to-end peripheral nerve repair. To evaluate the influence of the number of stitches on axonal regeneration and collagen production after neurorrhaphy. Thirty male Wistar rats were equally divided into 3 groups and were all operated on with the right sciatic nerve exposed. In 2 groups, the nerve was sectioned and repaired by means of 3 (group B) or 6 (group C) epineurium sutures with 10-0 monofilament nylon. One group (group A) was used as a control. Each animal from groups B and C underwent electrophysiological evaluation with motor action potential recordings before nerve section and again at an 8-week interval after neurorrhaphy. Nerve biopsy specimens were used for histomorphometric assessment of axonal regeneration and quantification of collagen at the repair site. Animals from group C had significantly lower motor action potential conduction velocities compared with control animals (P=.02), and no significant difference was seen between groups B and C. Parameters obtained from morphometric evaluation were not significantly different between these 2 groups. Type I collagen and III collagen in the epineurium were significantly higher in group C than in either the control group (P=.001 and P=.003) or group B (P=.01 and P=.02). No differences were identified for collagen I and III in the endoneurium. Using 6 sutures for nerve repair is associated with worse electrophysiological outcomes and higher amounts of type I and III collagen in the epineurium compared with control. Neurorraphy with 6 stitches is also related to a significant increase in epineurium collagen I and III compared with 3-stitch neurorraphy. Copyright (C) by the Congress of Neurological Surgeons

Initial load-to-failure and failure analysis in single- and double-row repair techniques for rotator cuff repair.

PubMed

Baums, M H; Buchhorn, G H; Gilbert, F; Spahn, G; Schultz, W; Klinger, H-M

2010-09-01

This experimental study aimed to compare the load-to-failure rate and stiffness of single- versus double-row suture techniques for repairing rotator cuff lesions using two different suture materials. Additionally, the mode of failure of each repair was evaluated. In 32 sheep shoulders, a standardized tear of the infraspinatus tendon was created. Then, n = 8 specimen were randomized to four repair methods: (1) Double-row Anchor Ethibond coupled with polyester sutures, USP No. 2; (2) Double-Row Anchor HiFi with polyblend polyethylene sutures, USP No. 2; (3) Single-Row Anchor Ethibond coupled with braided polyester sutures, USP No. 2; and (4) Single-Row Anchor HiFi with braided polyblend polyethylene sutures, USP No. 2. Arthroscopic Mason-Allen stitches were placed (single-row) and combined with medial horizontal mattress stitches (double-row). All specimens were loaded to failure at a constant displacement rate on a material testing machine. Group 4 showed lowest load-to-failure result with 155.7 +/- 31.1 N compared to group 1 (293.4 +/- 16.1 N) and group 2 (397.7 +/- 7.4 N) (P < 0.001). Stiffness was highest in group 2 (162 +/- 7.3 N/mm) and lowest in group 4 (84.4 +/- 19.9 mm) (P < 0.001). In group 4, the main cause of failure was due to the suture cutting through the tendon (n = 6), a failure case observed in only n = 1 specimen in group 2 (P < 0.001). A double-row technique combined with arthroscopic Mason-Allen/horizontal mattress stitches provides high initial failure strength and may minimize the risk of the polyethylene sutures cutting through the tendon in rotator cuff repair when a single load force is used.

An ad hoc 3D-printed tool facilitates intraesophageal suturing in experimental surgery

PubMed Central

Steinemann, D.C.; Müller, P.C.; Apitz, M.; Nickel, F.; Kenngott, H.G.; Müller-Stich, B.P.; Linke, G.R.

2018-01-01

Background Three-dimensional printing (3DP) has become popular for development of anatomic models, preoperative planning, and production of tailored implants. A novel laparoscopic, transgastric procedure for distal esophageal mucosectomy was developed. During this procedure a space holder had to be introduced into the distal esophagus for exposure during suturing. The production process and evaluation of a 3DP space holder are described herein. Material and methods Computer-aided design software was used to develop models printed from polylactic acid. The prototype was adapted after testing in a cadaveric model. Subsequently the device was evaluated in a non-survival porcine model. A mucosal purse-string suture was placed as orally as possible in the esophagus, in the intervention group with and in the control group without use of the tool (n=8 each). The distance of the stitches from the Z-line was measured. The variability of stitches indicated the suture quality. Results The median maximum distance from Z-line to purse-string suture was larger in the intervention group (5.0 [3.3-6.4] versus 2.4 [2.0-4.1] cm;P=0.013). The time taken to place the sutures was shorter in the control group (P<0.001). Stitch variance tended to be greater in the intervention group (2.3 [0.9-2.5] versus 0.7 [0.2-0.4] cm;P=0.051). The time required for design and production of a tailored tool was below 24 h. Conclusions 3DP in experimental surgery enables rapid production, permits repeated adaptation until a tailored tool is obtained, and ensures independence from industrial partners. With the aid of the space holder more orally located esophageal lesions came within reach. PMID:29433890

Endoluminal Revision (OverStitch (TM) , Apollo Endosurgery) of the Dilated Gastroenterostomy in Patients with Late Dumping Syndrome After Proximal Roux-en-Y Gastric Bypass.

PubMed

Stier, Christine; Chiappetta, Sonja

2016-08-01

Dumping syndrome is a long-term postoperative complication of Roux-en-Y gastric bypass procedures. Morphologically, dumping syndrome usually correlates with a dilatation of the gastroenterostomy with accelerated pouch emptying. Conservative therapy includes diet changes, complementary pharmacotherapy and, if symptoms persist, surgical revision. Surgical options include endoscopic, endoluminal surgery to constrict the gastrojejunostomy using a novel endoscopic suturing device (OverStitch(TM), Apollo). In our study, we aimed to assess the viability, safety and efficacy of this procedure in patients with late dumping; 14 patients who had developed late dumping syndrome underwent surgery using an endoscopic suturing technique (OverStitch(TM), Apollo). Late dumping was confirmed by Sigstad score and an oral glucose tolerance test (OGTT). Prior to surgery, objective analysis of pouch emptying speed was assessed by gastric scintigraphy. Surgery was performed under general anaesthesia. None of the 14 patients suffered intra- or postoperative complications. No postsurgical increase in inflammation parameters was observed. The postinterventional pain scale (visual analogue scale) showed a mean score of 0.5 (range 0-10). In 13 of the 14 patients, no dumping was observed 1-month postsurgery. The postoperative Sigstad score (3.07 ± 2.06; range 1-9) showed an impressive reduction compared with the preoperative score (12.71 ± 4.18; range 7-24) (p < 0.001). Postoperative upper gastrointestinal gastrografin swallow revealed regular emptying in all the patients. The endoluminal endoscopic suturing technique-applied here for surgical revision of gastroenterostomy following Roux-en-Y gastric bypass-represents a promising, novel therapeutic option in late dumping syndrome involving minimal trauma and offering rapid reconvalescence.

Blast-Absorbing Bag

NASA Technical Reports Server (NTRS)

Kahn, Jon B.

1992-01-01

Proposed expandable bag contains debris from explosion. Permanently surrounds vessel or devices prone to explosive disintegration or slipped around small bomb. Finned cells shaped like outward-opening cups. Cells built up from overlapped sheets of fabric and stitched together to form expandable polyhedral bag. Cells pentagonal, triangular or square.

Patchwork Plagiarism

ERIC Educational Resources Information Center

Cooper, Janice

2007-01-01

In this Information Age, students produce research projects by piecing together passages quoted verbatim and stitched together with a few introductory or transitional words. They assemble research as patchwork quilts rather than weaving a fabric of new knowledge. This common practice raises ethical issues and poses new challenges for library media…

Alpha trimmed correlation for touchless finger image mosaicing

NASA Astrophysics Data System (ADS)

Rao, Shishir P.; Rajendran, Rahul; Agaian, Sos S.; Mulawka, Marzena Mary Ann

2016-05-01

In this paper, a novel technique to mosaic multiview contactless finger images is presented. This technique makes use of different correlation methods, such as, the Alpha-trimmed correlation, Pearson's correlation [1], Kendall's correlation [2], and Spearman's correlation [2], to combine multiple views of the finger. The key contributions of the algorithm are: 1) stitches images more accurately, 2) provides better image fusion effects, 3) has better visual effect on the overall image, and 4) is more reliable. The extensive computer simulations show that the proposed method produces better or comparable stitched images than several state-of-the-art methods, such as those presented by Feng Liu [3], K Choi [4], H Choi [5], and G Parziale [6]. In addition, we also compare various correlation techniques with the correlation method mentioned in [3] and analyze the output. In the future, this method can be extended to obtain a 3D model of the finger using multiple views of the finger, and help in generating scenic panoramic images and underwater 360-degree panoramas.

Influence of Ca2+ on the mechanosensitivity of the hair cells in the lateral line organs of Necturus maculosus.

PubMed

Jørgensen, F

1983-08-01

The degree of synchronization (DOS) between the afferent spike activity from one stitch of the lateral line of Necturus maculosus (in vivo) and the mechanical stimulation of one neuromast of the same stitch was measured under different circumstances. The DOS was found to be independent of changes in the concentration of monovalent cations (Na+, K+ and choline+) in the bulk solution at high Ca concentration (1 mM). DOS was also independent of the Ca concentration in the range 1 mM-1 microM in Tris-HCl buffer, but was markedly reduced at Ca = 10 microM in MOPS-KOH buffer. The reduced DOS, however, could be restored by addition of 10-20 mM KCl. 5 mM of 4-aminopyridine did not influence the DOS at high Ca concentration, but completely reduced DOS at Ca = 10 microM. D600 (a methoxy derivative of verapamil) decreased DOS both at high and low Ca concentration.

Imaging a Large Sample with Selective Plane Illumination Microscopy Based on Multiple Fluorescent Microsphere Tracking

NASA Astrophysics Data System (ADS)

Ryu, Inkeon; Kim, Daekeun

2018-04-01

A typical selective plane illumination microscopy (SPIM) image size is basically limited by the field of view, which is a characteristic of the objective lens. If an image larger than the imaging area of the sample is to be obtained, image stitching, which combines step-scanned images into a single panoramic image, is required. However, accurately registering the step-scanned images is very difficult because the SPIM system uses a customized sample mount where uncertainties for the translational and the rotational motions exist. In this paper, an image registration technique based on multiple fluorescent microsphere tracking is proposed in the view of quantifying the constellations and measuring the distances between at least two fluorescent microspheres embedded in the sample. Image stitching results are demonstrated for optically cleared large tissue with various staining methods. Compensation for the effect of the sample rotation that occurs during the translational motion in the sample mount is also discussed.

Ultrahard stitching of nanotwinned diamond and cubic boron nitride in C 2-BN composite

DOE PAGES

Liu, Xiaobing; Chen, Xin; Ma, Hong-An; ...

2016-07-27

Materials combining the hardness and strength of diamond with the higher thermal stability of cubic boron nitride (cBN) have broad potential value in science and engineering. Reacting nanodiamond with cBN at moderate pressures and high temperatures provides a pathway to such materials. Here we report the fabrication of C x-BN nanocomposites, measuring up to 10 mm in longest dimension, by reacting nanodiamond with pre-synthesized cBN in a large-volume press. The nanocomposites consist of randomly-oriented diamond and cBN domains stitched together by sp 3-hybridized C-B and C-N bonds, leading to p-type semiconductivity. Dislocations near the sutures accommodate lattice mismatch between diamondmore » and cBN. Nanotwinning within both diamond and cBN domains further contributes to a bulk hardness ~50% higher than sintered cBN. We find the nanocomposite of C 2-BN exhibits p-type semiconductivity with low activation energy and high thermal stability, making it a functional,ultrahard substance.« less

Rapid, automated mosaicking of the human corneal subbasal nerve plexus.

PubMed

Vaishnav, Yash J; Rucker, Stuart A; Saharia, Keshav; McNamara, Nancy A

2017-11-27

Corneal confocal microscopy (CCM) is an in vivo technique used to study corneal nerve morphology. The largest proportion of nerves innervating the cornea lie within the subbasal nerve plexus, where their morphology is altered by refractive surgery, diabetes and dry eye. The main limitations to clinical use of CCM as a diagnostic tool are the small field of view of CCM images and the lengthy time needed to quantify nerves in collected images. Here, we present a novel, rapid, fully automated technique to mosaic individual CCM images into wide-field maps of corneal nerves. We implemented an OpenCV image stitcher that accounts for corneal deformation and uses feature detection to stitch CCM images into a montage. The method takes 3-5 min to process and stitch 40-100 frames on an Amazon EC2 Micro instance. The speed, automation and ease of use conferred by this technique is the first step toward point of care evaluation of wide-field subbasal plexus (SBP) maps in a clinical setting.

Suspension string: a new method of aortic valvuloplasty for aortic insufficiency and ventricular septal defect.

PubMed

Huang, Zhixiong

2006-09-01

In a 4-year-old boy with ventricular septal defect, severe aortic insufficiency, and mild infundibular stenosis, a new method was used to reconstruct the prolapsed aortic cusp. Two ends of a pledged stitch were passed through the aorta at each side of the right, noncoronary commissure and then through another pledget, and were then tied repeatedly in a row. The length of the row of knots was equal to that of the free edge of left coronary or noncoronary leaflet. The remainder of the stitch was passed through a pledget and then the aortic wall at each side of the left and right coronary commissure to the extraaortic wall pledget and were tied. A suspension string was formed by the row of knots and supported by a Teflon (Dupont Teflon, Wilmington, DE) felt pledget sandwich at each of two commissures. The free margin of the prolapsed cusp was attached to the suspension string by a continuous suture. The concomitant anomalies were corrected. The result was satisfactory.

In vitro assessment of ultraviolet protection of coloured cotton knitted fabrics with different structures under stretched and wet conditions.

PubMed

Wong, W Y; Lam, J K C; Kan, C W; Postle, R

2015-04-01

Clothing provides intrinsic ultraviolet (UV) protection that can be improved by colouration. However, the daily wearing condition can undermine the UV protection of coloured clothing wherein garments are stretched by body movement and/or wetted by perspiration of wearers. Knitwear is an indispensable clothing in summer, but its UV protection against wearing conditions lacks extensive study especially in a fabric structural approach. This article aimed at narrowing the research gap by focusing on the UV protection against stretch and wetness provided by various knitted fabric constructions incorporating the knit, tuck and miss stitches. The results show that the black knitted fabrics exhibit a significant reduction in the UV protection factor by 53% on average at a 10% stretch level. Knitted fabrics with miss stitches retained good UV protection even when the fabrics were stretched by 20% of its original dimensions. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Stitch overlap via coloring technique enables maskless via

NASA Astrophysics Data System (ADS)

Civay, D.; Laffosse, E.

2017-03-01

Lithographic patterning limits can be a cost-barrier that delays advancement to new nodes. This paper introduces a cost-saving design method that enables a maskless via. Multi-patterning or coloring of a design is a technique that is used at advanced nodes to aid in patterning. Coloring allows designers to designate different patterns on one level to be printed with different masks. Stitch overlap via (SOV) is a coloring technique introduced herein. SOV utilizes via-aware coloring and a unique process flow to print a maskless via. Identification of qualifying design structures is achieved through a custom program. The program inputs the design level of the multipatterned layer and the via levels above and below to determine the coloring decomposition. Vias are a particularly challenging layer to print due to the dimensions required for these pillars. SOV is a methodology for identifying qualifying multi-patterned layouts and replacing them with a new design that enables a maskless via layer.

Stitching h-BN by atomic layer deposition of LiF as a stable interface for lithium metal anode

PubMed Central

Xie, Jin; Liao, Lei; Gong, Yongji; Li, Yanbin; Shi, Feifei; Pei, Allen; Sun, Jie; Zhang, Rufan; Kong, Biao; Subbaraman, Ram; Christensen, Jake; Cui, Yi

2017-01-01

Defects are important features in two-dimensional (2D) materials that have a strong influence on their chemical and physical properties. Through the enhanced chemical reactivity at defect sites (point defects, line defects, etc.), one can selectively functionalize 2D materials via chemical reactions and thereby tune their physical properties. We demonstrate the selective atomic layer deposition of LiF on defect sites of h-BN prepared by chemical vapor deposition. The LiF deposits primarily on the line and point defects of h-BN, thereby creating seams that hold the h-BN crystallites together. The chemically and mechanically stable hybrid LiF/h-BN film successfully suppresses lithium dendrite formation during both the initial electrochemical deposition onto a copper foil and the subsequent cycling. The protected lithium electrodes exhibit good cycling behavior with more than 300 cycles at relatively high coulombic efficiency (>95%) in an additive-free carbonate electrolyte. PMID:29202031

Stitching h-BN by atomic layer deposition of LiF as a stable interface for lithium metal anode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Jin; Liao, Lei; Gong, Yongji

Defects are important features in two-dimensional (2D) materials that have a strong influence on their chemical and physical properties. Through the enhanced chemical reactivity at defect sites (point defects, line defects, etc.), one can selectively functionalize 2D materials via chemical reactions and thereby tune their physical properties. We demonstrate the selective atomic layer deposition of LiF on defect sites of h-BN prepared by chemical vapor deposition. The LiF deposits primarily on the line and point defects of h-BN, thereby creating seams that hold the h-BN crystallites together. The chemically and mechanically stable hybrid LiF/h-BN film successfully suppresses lithium dendrite formationmore » during both the initial electrochemical deposition onto a copper foil and the subsequent cycling. In conclusion, the protected lithium electrodes exhibit good cycling behavior with more than 300 cycles at relatively high coulombic efficiency (>95%) in an additive-free carbonate electrolyte.« less

Formation of Graphene Grain Boundaries on Cu(100) Surface and a Route Towards Their Elimination in Chemical Vapor Deposition Growth

NASA Astrophysics Data System (ADS)

Yuan, Qinghong; Song, Guangyao; Sun, Deyan; Ding, Feng

2014-10-01

Grain boundaries (GBs) in graphene prepared by chemical vapor deposition (CVD) greatly degrade the electrical and mechanical properties of graphene and thus hinder the applications of graphene in electronic devices. The seamless stitching of graphene flakes can avoid GBs, wherein the identical orientation of graphene domain is required. In this letter, the graphene orientation on one of the most used catalyst surface -- Cu(100) surface, is explored by density functional theory (DFT) calculations. Our calculation demonstrates that a zigzag edged hexagonal graphene domain on a Cu(100) surface has two equivalent energetically preferred orientations, which are 30 degree away from each other. Therefore, the fusion of graphene domains on Cu(100) surface during CVD growth will inevitably lead to densely distributed GBs in the synthesized graphene. Aiming to solve this problem, a simple route, that applies external strain to break the symmetry of the Cu(100) surface, was proposed and proved efficient.

Image Geometric Corrections for a New EMCCD-based Dual Modular X-ray Imager

PubMed Central

Qu, Bin; Huang, Ying; Wang, Weiyuan; Cartwright, Alexander N.; Titus, Albert H.; Bednarek, Daniel R.; Rudin, Stephen

2012-01-01

An EMCCD-based dual modular x-ray imager was recently designed and developed from the component level, providing a high dynamic range of 53 dB and an effective pixel size of 26 μm for angiography and fluoroscopy. The unique 2×1 array design efficiently increased the clinical field of view, and also can be readily expanded to an M×N array implementation. Due to the alignment mismatches between the EMCCD sensors and the fiber optic tapers in each module, the output images or video sequences result in a misaligned 2048×1024 digital display if uncorrected. In this paper, we present a method for correcting display registration using a custom-designed two layer printed circuit board. This board was designed with grid lines to serve as the calibration pattern, and provides an accurate reference and sufficient contrast to enable proper display registration. Results show an accurate and fine stitching of the two outputs from the two modules. PMID:22254882

Stitching h-BN by atomic layer deposition of LiF as a stable interface for lithium metal anode

DOE PAGES

Xie, Jin; Liao, Lei; Gong, Yongji; ...

2017-11-29

Defects are important features in two-dimensional (2D) materials that have a strong influence on their chemical and physical properties. Through the enhanced chemical reactivity at defect sites (point defects, line defects, etc.), one can selectively functionalize 2D materials via chemical reactions and thereby tune their physical properties. We demonstrate the selective atomic layer deposition of LiF on defect sites of h-BN prepared by chemical vapor deposition. The LiF deposits primarily on the line and point defects of h-BN, thereby creating seams that hold the h-BN crystallites together. The chemically and mechanically stable hybrid LiF/h-BN film successfully suppresses lithium dendrite formationmore » during both the initial electrochemical deposition onto a copper foil and the subsequent cycling. In conclusion, the protected lithium electrodes exhibit good cycling behavior with more than 300 cycles at relatively high coulombic efficiency (>95%) in an additive-free carbonate electrolyte.« less

Retinal optical coherence tomography at 1 μm with dynamic focus control and axial motion tracking

NASA Astrophysics Data System (ADS)

Cua, Michelle; Lee, Sujin; Miao, Dongkai; Ju, Myeong Jin; Mackenzie, Paul J.; Jian, Yifan; Sarunic, Marinko V.

2016-02-01

High-resolution optical coherence tomography (OCT) retinal imaging is important to noninvasively visualize the various retinal structures to aid in better understanding of the pathogenesis of vision-robbing diseases. However, conventional OCT systems have a trade-off between lateral resolution and depth-of-focus. In this report, we present the development of a focus-stacking OCT system with automatic focus optimization for high-resolution, extended-focal-range clinical retinal imaging by incorporating a variable-focus liquid lens into the sample arm optics. Retinal layer tracking and selection was performed using a graphics processing unit accelerated processing platform for focus optimization, providing real-time layer-specific en face visualization. After optimization, multiple volumes focused at different depths were acquired, registered, and stitched together to yield a single, high-resolution focus-stacked dataset. Using this system, we show high-resolution images of the retina and optic nerve head, from which we extracted clinically relevant parameters such as the nerve fiber layer thickness and lamina cribrosa microarchitecture.

Retinal optical coherence tomography at 1 μm with dynamic focus control and axial motion tracking.

PubMed

Cua, Michelle; Lee, Sujin; Miao, Dongkai; Ju, Myeong Jin; Mackenzie, Paul J; Jian, Yifan; Sarunic, Marinko V

2016-02-01

High-resolution optical coherence tomography (OCT) retinal imaging is important to noninvasively visualize the various retinal structures to aid in better understanding of the pathogenesis of vision-robbing diseases. However, conventional OCT systems have a trade-off between lateral resolution and depth-of-focus. In this report, we present the development of a focus-stacking OCT system with automatic focus optimization for high-resolution, extended-focal-range clinical retinal imaging by incorporating a variable-focus liquid lens into the sample arm optics. Retinal layer tracking and selection was performed using a graphics processing unit accelerated processing platform for focus optimization, providing real-time layer-specific en face visualization. After optimization, multiple volumes focused at different depths were acquired, registered, and stitched together to yield a single, high-resolution focus-stacked dataset. Using this system, we show high-resolution images of the retina and optic nerve head, from which we extracted clinically relevant parameters such as the nerve fiber layer thickness and lamina cribrosa microarchitecture.

Combination laser treatment for immediate post-surgical scars: a retrospective analysis of 33 immature scars.

PubMed

Lee, Yongsoo; Kim, Wooram

2017-07-01

The application of laser treatments beginning on the day of stitch removal has been demonstrated to improve scar quality. However, there are few guidelines for the treatment of immature scars (ISs), which are defined as "scars whose features are not yet expressed." The purpose of this study was to extract information about early combination laser treatment (CLT) beyond what is currently known by analyzing 33 pairs of pre-treatment and post-treatment photographs of ISs. Two hundred fifty medical records of patients with scars were reviewed, and 33 scars were included in the study. The included scars were treated with vascular lasers (585 or 532 nm) followed by 1550-nm fractional lasers from May 2014 to July 2015 (fewer than 52 days after stitch removal, Fitzpatrick's skin types III-IV, mean age = 16.0 years). Blinded evaluators (one plastic surgeon and two dermatologists) evaluated the pre-treatment and post-treatment photographs. The pre-treatment photographs were scored on a spectrum from "0," when no difference with the surrounding unaffected skin was observed, to "100," when the worst scarring was present. The pre-treatment and post-treatment photographs were compared, and the results were graded on a spectrum from 0, when no difference between the pre-treatment and post-treatment photographs was observed, to 100, when no difference was observed between the post-treatment skin and the surrounding unaffected skin. Statistical analyses were performed with PASW 17.0, SPSS Korea, Seoul, Korea (p < 0.05). The improvement scores (ImS) and weighted scores (Wtd: i.e., weighted according to the pre-treatment scores) were used as dependent variables. The average improvement score was 87.98 (median = 90). Seventeen cases were scored as 100-point improvements. The facial and non-facial scars exhibited differences in the ImS and Wtd scores. The Wtd scores were negatively correlated with the temporal gap (in days) between stitch removal and the beginning of CLT. No significant difference in the Wtd scores was demonstrated between the two vascular laser groups. Patient age and Wtd score were negatively correlated, and a significant difference was observed in the Wtd scores between the age groups (≥15 and <15 years old). CLT for ISs results in excellent outcomes. Better results are achieved with earlier CLT initiation following stitch removal. Better outcomes can be expected for younger patients and for facial scars. We found that 532 and 585-nm lasers are equally effective for CLT of ISs.

Stitching Circuits: Learning about Circuitry through E-Textile Materials

ERIC Educational Resources Information Center

Peppler, Kylie; Glosson, Diane

2013-01-01

Central to our understanding of learning is the relationship between various tools and technologies and the structuring of disciplinary subject matter. One of the staples of early science education curriculum is the use of electrical circuit toolkits to engage students in broader discussions of energy. Traditionally, these concepts are introduced…

The Stitches Stayed: Creating Rapport around Women's Work

ERIC Educational Resources Information Center

Wall, Mary Clementine; Stasz, Bird

2010-01-01

Establishing rapport between researcher and participants when conducting ethnography is essential to the successful outcome of the research. However, when participants are unwilling to engage, a different approach must be adopted. This article is an examination of the appropriation of a situated learning model during fieldwork with a group of…

16 CFR 1616.4 - Sampling and acceptance procedures.

Code of Federal Regulations, 2014 CFR

2014-01-01

... a suitable thread and stitch. The specimen shall include each of the components over its entire... fabric in Tightened Sampling must be discontinued until that part of the process or component which is... otherwise attaching the trim shall be done with thread or fastening material of the same composition and...

Threading "Stitches" to Approach Gender Identity, Sexual Identity, and Difference

ERIC Educational Resources Information Center

North, Connie E.

2010-01-01

As LGBTQI (lesbian, gay, bisexual, transgender, queer/questioning, and intersex) issues become increasingly integrated into multicultural education discourses, we as educators need to examine the implications of our pedagogies for teaching about gender and sexual identities. This article explores my teaching of non-conforming gender identities in…

46 CFR 160.005-1 - Incorporation by reference.

Code of Federal Regulations, 2014 CFR

2014-10-01

... makes reference to the following documents: (1) Federal Specification: L-P-375C—Plastic Film, Flexible....005-1: (Sheet 1) Cutting Pattern and General Arrangement (Adult). (Sheet 2) Alternate Stitching of Tapes and Webbing (Adult and Child). (Sheet 3) Pad Detail (Adult). (Sheet 4) Cutting Pattern and General...

46 CFR 160.005-1 - Incorporation by reference.

Code of Federal Regulations, 2013 CFR

2013-10-01

... makes reference to the following documents: (1) Federal Specification: L-P-375C—Plastic Film, Flexible....005-1: (Sheet 1) Cutting Pattern and General Arrangement (Adult). (Sheet 2) Alternate Stitching of Tapes and Webbing (Adult and Child). (Sheet 3) Pad Detail (Adult). (Sheet 4) Cutting Pattern and General...

46 CFR 160.005-1 - Incorporation by reference.

Code of Federal Regulations, 2012 CFR

2012-10-01

... makes reference to the following documents: (1) Federal Specification: L-P-375C—Plastic Film, Flexible....005-1: (Sheet 1) Cutting Pattern and General Arrangement (Adult). (Sheet 2) Alternate Stitching of Tapes and Webbing (Adult and Child). (Sheet 3) Pad Detail (Adult). (Sheet 4) Cutting Pattern and General...

46 CFR 160.005-1 - Incorporation by reference.

Code of Federal Regulations, 2011 CFR

2011-10-01

... makes reference to the following documents: (1) Federal Specification: L-P-375C—Plastic Film, Flexible....005-1: (Sheet 1) Cutting Pattern and General Arrangement (Adult). (Sheet 2) Alternate Stitching of Tapes and Webbing (Adult and Child). (Sheet 3) Pad Detail (Adult). (Sheet 4) Cutting Pattern and General...

[Successful treatment of injuries of the abdominal aorta].

PubMed

Merkl, J; Bat'alík, B; Mydlo, J

1990-03-01

The authors describe successful treatment of severe haemorrhagic shock caused by profuse haemorrhage from the infrarenal portion of the abdominal aorta. After primary treatment of the perforation by a vascular suture reoperation was necessary because of repeated haemorrhage from that site, and for closure of the dehiscence Dacron stitch was used.

The BRAID: Experiments in Stitching Together Disciplines at a Big Ten University

ERIC Educational Resources Information Center

Luckie, Douglas B.; Bellon, Richard; Sweeder, Ryan D.

2012-01-01

Since 2005 we have pursued a formal research program called the BRAID (Bringing Relationships Alive through Interdisciplinary Discourse), which is designed to develop and test strategies for training first- and second-year undergraduate science students to bridge scientific disciplines. The BRAID's ongoing multiyear investigation points to…

Fast Faraday Cup With High Bandwidth

DOEpatents

Deibele, Craig E [Knoxville, TN

2006-03-14

A circuit card stripline Fast Faraday cup quantitatively measures the picosecond time structure of a charged particle beam. The stripline configuration maintains signal integrity, and stitching of the stripline increases the bandwidth. A calibration procedure ensures the measurement of the absolute charge and time structure of the charged particle beam.

Crazy Quilt Project

ERIC Educational Resources Information Center

Flood, LaDora

2007-01-01

One of the author's earliest recollections is going with her mother up into her grandmother's bedroom to look in a very old chest. The chest contains quilts that have been in the family for generations. Fascinated by quilt colors, designs, and tiny stitches, the author shares this with her fifth-grade classes by making a paper quilt at school.…

Let Me Do It: Children's Art with Less Stress and More Success.

ERIC Educational Resources Information Center

Spears, Jo Ann Lohl

2002-01-01

Offers suggestions for incorporating inexpensive art activities into early childhood classrooms. Suggests activities for children over 3 years in the areas of art using: paint and food coloring, drawing or scribbling, sculpture or construction, weaving and stitching, clay and dough, paper scraps, and broken crayons. Suggests craft activities for…

Bluebonnet Fiber Collages

ERIC Educational Resources Information Center

Sterling, Joan

2009-01-01

This article presents a lesson that uses stitching and applique techniques to create a fiber collage in which every child is successful with high-quality work. This lesson was inspired by Tomie dePaola's "The Legend of the Bluebonnet." The back cover had a lovely illustration of the bluebonnet flower the author thought would translate easily to a…

Why I Make Books

ERIC Educational Resources Information Center

Mayers, Leah

2009-01-01

In this article, the author relates how she discovered that she was a book and paper artist after she had been kicked out of two high schools, went to art school, had a degree in Political Science and Women's Studies, had another one in Education, and was teaching school full time. After she constructed and stitched her first multisection…

Surgical Technology Integration with Tools for Cognitive Human Factors (STITCH)

DTIC Science & Technology

2010-10-01

Measurement Tool We conducted another round of data collection using the daVinci Surgical System at the University of Kentucky Hospital in May. In this...9 3. Tools and Display Technology...considering cognitive and environmental factors such as mental workload, stress, situation awareness, and level of comfort with complex tools . To

46 CFR 160.002-1 - Incorporation by reference.

Code of Federal Regulations, 2014 CFR

2014-10-01

.... General Purpose, Natural or in Colors. (2) Federal Specification: L-P-375—Plastic Film, Flexible, Vinyl...: (Sheet 1) Cutting Pattern and General Arrangement (adult). (Sheet 1A) Alternate stitching of tapes and webbing (adult and child). (Sheet 2) Pad Detail (adult). Dwg. No. F-49-6-5: (Sheet 1) Cutting Pattern and...

46 CFR 160.002-1 - Incorporation by reference.

Code of Federal Regulations, 2013 CFR

2013-10-01

.... General Purpose, Natural or in Colors. (2) Federal Specification: L-P-375—Plastic Film, Flexible, Vinyl...: (Sheet 1) Cutting Pattern and General Arrangement (adult). (Sheet 1A) Alternate stitching of tapes and webbing (adult and child). (Sheet 2) Pad Detail (adult). Dwg. No. F-49-6-5: (Sheet 1) Cutting Pattern and...

46 CFR 160.002-1 - Incorporation by reference.

Code of Federal Regulations, 2010 CFR

2010-10-01

.... General Purpose, Natural or in Colors. (2) Federal Specification: L-P-375—Plastic Film, Flexible, Vinyl...: (Sheet 1) Cutting Pattern and General Arrangement (adult). (Sheet 1A) Alternate stitching of tapes and webbing (adult and child). (Sheet 2) Pad Detail (adult). Dwg. No. F-49-6-5: (Sheet 1) Cutting Pattern and...

46 CFR 160.002-1 - Incorporation by reference.

Code of Federal Regulations, 2011 CFR

2011-10-01

.... General Purpose, Natural or in Colors. (2) Federal Specification: L-P-375—Plastic Film, Flexible, Vinyl...: (Sheet 1) Cutting Pattern and General Arrangement (adult). (Sheet 1A) Alternate stitching of tapes and webbing (adult and child). (Sheet 2) Pad Detail (adult). Dwg. No. F-49-6-5: (Sheet 1) Cutting Pattern and...

46 CFR 160.002-1 - Incorporation by reference.

Code of Federal Regulations, 2012 CFR

2012-10-01

.... General Purpose, Natural or in Colors. (2) Federal Specification: L-P-375—Plastic Film, Flexible, Vinyl...: (Sheet 1) Cutting Pattern and General Arrangement (adult). (Sheet 1A) Alternate stitching of tapes and webbing (adult and child). (Sheet 2) Pad Detail (adult). Dwg. No. F-49-6-5: (Sheet 1) Cutting Pattern and...

49 CFR 178.816 - Topple test.

Code of Federal Regulations, 2011 CFR

2011-10-01

... be no loss of contents. A slight discharge (e.g., from closures or stitch holes) upon impact is not considered to be a failure, provided no further leakage occurs. [Amdt. 178-103, 59 FR 38074, July 26, 1994... than 95 percent of its capacity and to its maximum net mass, with the load being evenly distributed. (c...

49 CFR 178.816 - Topple test.

Code of Federal Regulations, 2013 CFR

2013-10-01

... be no loss of contents. A slight discharge (e.g., from closures or stitch holes) upon impact is not considered to be a failure, provided no further leakage occurs. [Amdt. 178-103, 59 FR 38074, July 26, 1994... than 95 percent of its capacity and to its maximum net mass, with the load being evenly distributed. (c...

49 CFR 178.816 - Topple test.

Code of Federal Regulations, 2010 CFR

2010-10-01

.... For all flexible IBCs, there may be no loss of contents. A slight discharge (e.g., from closures or stitch holes) upon impact is not considered to be a failure, provided no further leakage occurs. [Amdt... must be filled to not less than 95 percent of its capacity and to its maximum net mass, with the load...

49 CFR 178.816 - Topple test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... be no loss of contents. A slight discharge (e.g., from closures or stitch holes) upon impact is not considered to be a failure, provided no further leakage occurs. [Amdt. 178-103, 59 FR 38074, July 26, 1994... than 95 percent of its capacity and to its maximum net mass, with the load being evenly distributed. (c...

49 CFR 178.816 - Topple test.

Code of Federal Regulations, 2012 CFR

2012-10-01

... be no loss of contents. A slight discharge (e.g., from closures or stitch holes) upon impact is not considered to be a failure, provided no further leakage occurs. [Amdt. 178-103, 59 FR 38074, July 26, 1994... than 95 percent of its capacity and to its maximum net mass, with the load being evenly distributed. (c...

46 CFR 160.047-4 - Construction.

Code of Federal Regulations, 2010 CFR

2010-10-01

... and Child § 160.047-4 Construction. (a) General. This specification covers buoyant vests which... pattern shown on Dwg. No. 160.047-1, Sheet 1, for adult size, and Sheets 2 and 3 for child sizes, and sewed with seams and stitching as shown on the drawing. Three compartments shall be formed to hold the...

49 CFR 178.940 - Standards for flexible Large Packagings.

Code of Federal Regulations, 2011 CFR

2011-10-01

... the construction of the flexible Large Packagings must be appropriate to its capacity and its intended... complete immersion in water for not less than 24 hours, retain at least 85 percent of the tensile strength... less. (3) Seams must be stitched or formed by heat sealing, gluing or any equivalent method. All...

A method to restrain the charging effect on an insulating substrate in high energy electron beam lithography

NASA Astrophysics Data System (ADS)

Mingyan, Yu; Shirui, Zhao; Yupeng, Jing; Yunbo, Shi; Baoqin, Chen

2014-12-01

Pattern distortions caused by the charging effect should be reduced while using the electron beam lithography process on an insulating substrate. We have developed a novel process by using the SX AR-PC 5000/90.1 solution as a spin-coated conductive layer, to help to fabricate nanoscale patterns of poly-methyl-methacrylate polymer resist on glass for phased array device application. This method can restrain the influence of the charging effect on the insulating substrate effectively. Experimental results show that the novel process can solve the problems of the distortion of resist patterns and electron beam main field stitching error, thus ensuring the accuracy of the stitching and overlay of the electron beam lithography system. The main characteristic of the novel process is that it is compatible to the multi-layer semiconductor process inside a clean room, and is a green process, quite simple, fast, and low cost. It can also provide a broad scope in the device development on insulating the substrate, such as high density biochips, flexible electronics and liquid crystal display screens.

A method of multi-view intraoral 3D measurement

NASA Astrophysics Data System (ADS)

Zhao, Huijie; Wang, Zhen; Jiang, Hongzhi; Xu, Yang; Lv, Peijun; Sun, Yunchun

2015-02-01

In dental restoration, its important to achieve a high-accuracy digital impression. Most of the existing intraoral measurement systems can only measure the tooth from a single view. Therfore - if we are wilng to acquire the whole data of a tooth, the scans of the tooth from multi-direction ad the data stitching based on the features of the surface are needed, which increases the measurement duration and influence the measurement accuracy. In this paper, we introduce a fringe-projection based on multi-view intraoral measurement system. It can acquire 3D data of the occlusal surface, the buccal surface and the lingual surface of a tooth synchronously, by using a senor with three mirrors, which aim at the three surfaces respectively and thus expand the measuring area. The constant relationship of the three mirrors is calibrated before measurement and can help stitch the data clouds acquired through different mirrors accurately. Therefore the system can obtain the 3D data of a tooth without the need to measure it from different directions for many times. Experiments proved the availability and reliability of this miniaturized measurement system.

Test and analysis of a stitched RFI graphite-epoxy panel with a fuel access door

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Waters, W. Allen, Jr.

1994-01-01

A stitched RFI graphite-epoxy panel with a fuel access door was analyzed using a finite element analysis and loaded to failure in compression. The panel was initially 56-inches long and 36.75-inches wide and the oval access door was 18-inches long and 15-inches wide. The panel was impact damaged with impact energy of 100 ft-lb prior to compressive loading; however, no impact damage was detectable visually or by A-scan. The panel carried a failure load of 695,000 Ib and global failure strain of .00494 in/in. Analysis indicated the panel would fail due to collapse at a load of 688,100 Ib. The test data indicate that the maximum strain in a region near the access door was .0096 in/in and analysis indicates a local surface strain of .010 in/in at the panel's failure load. The panel did not fail through the impact damage, but instead failed through bolt holes for attachment of the access door in a region of high strain.

Evaluation of RTM370 Polyimide Composites by Resin Film Infusion (RFI)

NASA Technical Reports Server (NTRS)

Chuang, Kathy C.; Yip, Thomas A.; Kollmansberger, Ronald B.; Tsotsis, Thomas K.

2014-01-01

RTM370 imide oligomer based on 2,3,3',4'-biphenyl dianhydride (a-BPDA), 3,4'-oxydianiline (3,4'-ODA) and terminated with the 4-phenylethynylphthalic (PEPA) endcap has been shown to exhibit a low melt viscosity (10-30 poise) at 280 C with a pot-life of 1-2 h and a high cured glass-transition temperature (Tg) of 370 C. RTM370 resin has been successfully infused into fiberglass-stitched T650-35 carbon-fabric preforms (ranged from 3- to 6-mm thick) by resin film infusion (RFI). The resulting composite panels were inspected by ultrasonic C-scan and by photomicrographs before and after post-curing as a quality control. Mechanical tests such as unnotched compression (UNC), open-hole compression (OHC), and short-beam shear strength (SBS) at ambient and elevated temperatures were performed before and after isothermal aging at 288 C for 1000 h to assess high-temperature performance. Thermal cycling of RTM370 stitched composites was also conducted from -54 C to 288 C for up to 1600 cycles to evaluate the microcrack resistance of RTM370 polyimide composites fabricated by RFI.

Fracture Behavior of a Stitched Warp-Knit Carbon Fabric Composite

NASA Technical Reports Server (NTRS)

Poe, Clarence C., Jr.; Reeder, James R.; Yuan, F. G.

2001-01-01

Tests were conducted on several types of fracture specimens made from a carbon/epoxy composite. The composite material was stitched prior to introducing epoxy resin. Boeing, used this material to develop a composite wing box for a transport aircraft in the NASA Advanced Composites Transport Program. The specimens included compact, extended compact, and center notched tension specimens. The specimens were cut from panels with three orientations in order to explore the effects of anisotropy. The panels were made with various thicknesses to represent a wing, skin from tip to root. All fractures were not self-similar depending on specimen type and orientation. Unnotched tension specimens were also tested to measure elastic constants and strengths. The normal and shear strains were calculated on fracture planes using a series representation of strain fields for plane anisotropic crack problems. The fracture parameters were determined using a finite element method. Characteristic distances for critical tension and shear strains were calculated for each specimen and a failure criterion based on the interaction of tension and shear strains was proposed.

Large area high-speed metrology SPM system.

PubMed

Klapetek, P; Valtr, M; Picco, L; Payton, O D; Martinek, J; Yacoot, A; Miles, M

2015-02-13

We present a large area high-speed measuring system capable of rapidly generating nanometre resolution scanning probe microscopy data over mm(2) regions. The system combines a slow moving but accurate large area XYZ scanner with a very fast but less accurate small area XY scanner. This arrangement enables very large areas to be scanned by stitching together the small, rapidly acquired, images from the fast XY scanner while simultaneously moving the slow XYZ scanner across the region of interest. In order to successfully merge the image sequences together two software approaches for calibrating the data from the fast scanner are described. The first utilizes the low uncertainty interferometric sensors of the XYZ scanner while the second implements a genetic algorithm with multiple parameter fitting during the data merging step of the image stitching process. The basic uncertainty components related to these high-speed measurements are also discussed. Both techniques are shown to successfully enable high-resolution, large area images to be generated at least an order of magnitude faster than with a conventional atomic force microscope.

Large area high-speed metrology SPM system

NASA Astrophysics Data System (ADS)

Klapetek, P.; Valtr, M.; Picco, L.; Payton, O. D.; Martinek, J.; Yacoot, A.; Miles, M.

2015-02-01

We present a large area high-speed measuring system capable of rapidly generating nanometre resolution scanning probe microscopy data over mm2 regions. The system combines a slow moving but accurate large area XYZ scanner with a very fast but less accurate small area XY scanner. This arrangement enables very large areas to be scanned by stitching together the small, rapidly acquired, images from the fast XY scanner while simultaneously moving the slow XYZ scanner across the region of interest. In order to successfully merge the image sequences together two software approaches for calibrating the data from the fast scanner are described. The first utilizes the low uncertainty interferometric sensors of the XYZ scanner while the second implements a genetic algorithm with multiple parameter fitting during the data merging step of the image stitching process. The basic uncertainty components related to these high-speed measurements are also discussed. Both techniques are shown to successfully enable high-resolution, large area images to be generated at least an order of magnitude faster than with a conventional atomic force microscope.

Compression Testing of Textile Composite Materials

NASA Technical Reports Server (NTRS)

Masters, John E.

1996-01-01

The applicability of existing test methods, which were developed primarily for laminates made of unidirectional prepreg tape, to textile composites is an area of concern. The issue is whether the values measured for the 2-D and 3-D braided, woven, stitched, and knit materials are accurate representations of the true material response. This report provides a review of efforts to establish a compression test method for textile reinforced composite materials. Experimental data have been gathered from several sources and evaluated to assess the effectiveness of a variety of test methods. The effectiveness of the individual test methods to measure the material's modulus and strength is determined. Data are presented for 2-D triaxial braided, 3-D woven, and stitched graphite/epoxy material. However, the determination of a recommended test method and specimen dimensions is based, primarily, on experimental results obtained by the Boeing Defense and Space Group for 2-D triaxially braided materials. They evaluated seven test methods: NASA Short Block, Modified IITRI, Boeing Open Hole Compression, Zabora Compression, Boeing Compression after Impact, NASA ST-4, and a Sandwich Column Test.

Experimental Results From Stitched Composite Multi-Bay Fuselage Panels Tested Under Uni-Axial Compression

NASA Technical Reports Server (NTRS)

Baker, Donald J.

2004-01-01

The experimental results from two stitched VARTM composite panels tested under uni-axial compression loading are presented. The curved panels are divided by frames and stringers into five or six bays with a column of three bays along the compressive loading direction. The frames are supported at the ends to resist out-of-plane translation. Back-to-back strain gages are used to record the strain and displacement transducers were used to record the out-of-plane displacements. In addition a full-field measurement technique that utilizes a camera-based-stero-vision system was used to record displacements. The panels were loaded in increments to determine the first bay to buckle. Loading was discontinued at limit load and the panels were removed from the test machine for impact testing. After impacting at 20 ft-lbs to 25 ft-lbs of energy with a spherical indenter, the panels were loaded in compression until failure. Impact testing reduced the axial stiffness 4 percent and less than 1 percent. Postbuckled axial panel stiffness was 52 percent and 70 percent of the pre-buckled stiffness.

Liver metastasis resection: a simple technique that makes it easier.

PubMed

de Santibañes, Eduardo; Sánchez Clariá, Rodrigo; Palavecino, Martín; Beskow, Axel; Pekolj, Juan

2007-09-01

Liver resection is the only therapeutic option that achieves long-term survival for patients with hepatic metastases. We propose a technique that causes traction and countertraction on the resection area, thus easily exposing the structures to be ligated. Because the parenchyma protrudes like a cork from a bottle, we named this procedure the "corkscrew technique". The objective of this work was to describe an original surgical technique to resect liver metastases. We delimit the resection area at 2 cm from the tumor. We place separated stitches, in a radiate way. The needle diameter must allow passing far from the deepest margin of the tumor. The stitches must be tractioned all together to separate the tumor from the normal parenchyma. Between the years 1983 and 2006, we perform 1,270 liver resections. We used the corkscrew technique-like procedure in only 612 patients, whereas in 129 patients, we associated it to an anatomic resection. Mortality was 1%. Morbidity was 16% with a reoperation rate of 3%. The corkscrew technique is simple and safe, spares surgical time, avoids blood loss, ensures free tumor margins, and is easy to perform.

A 400 KHz line rate 2048-pixel stitched SWIR linear array

NASA Astrophysics Data System (ADS)

Anchlia, Ankur; Vinella, Rosa M.; Gielen, Daphne; Wouters, Kristof; Vervenne, Vincent; Hooylaerts, Peter; Deroo, Pieter; Ruythooren, Wouter; De Gaspari, Danny; Das, Jo; Merken, Patrick

2016-05-01

Xenics has developed a family of stitched SWIR long linear arrays that operate up to 400 KHz of line rate. These arrays serve medical and industrial applications that require high line rates as well as space applications that require long linear arrays. The arrays are based on a modular ROIC design concept: modules of 512 pixels are stitched during fabrication to achieve 512, 1024 and 2048 pixel arrays. Each 512-pixel module has its own on-chip digital sequencer, analog readout chain and 4 output buffers. This modular concept enables a long array to run at a high line rates irrespective of the array length, which limits the line rate in a traditional linear array. The ROIC is flip-chipped with InGaAs detector arrays. The FPA has a pixel pitch of 12.5μm and has two pixel flavors: square (12.5μm) and rectangular (250μm). The frontend circuit is based on Capacitive Trans-impedance Amplifier (CTIA) to attain stable detector bias, and good linearity and signal integrity, especially at high speeds. The CTIA has an input auto-zero mechanism that allows to have low detector bias (<20mV). An on-chip Correlated Double Sample (CDS) facilitates removal of CTIA KTC and 1/f noise, and other offsets, achieving low noise performance. There are five gain modes in the FPA giving the full well range from 85Ke- to 40Me-. The measured input referred noise is 35e-rms in the highest gain mode. The FPA operates in Integrate While Read mode and, at a master clock rate of 60MHz and a minimum integration time of 1.4μs, achieves the highest line rate of 400 KHz. In this paper, design details and measurements results are presented in order to demonstrate the array performance.

The Sexual Function Questionnaire's Medical Impact Scale (SFQ-MIS): validation among a sample of first-time mothers.

PubMed

Jawed-Wessel, Sofia; Schick, Vanessa; Herbenick, Debby

2013-11-01

Changes in sexual function can be difficult to capture, especially when an attempt is made to assess the effects of pregnancy or childbirth on the sexual function of first-time mothers. Commonly used sexual function measures are limited and fail to account for pregnancy or birth in assessment of function. The purpose of this study was to explore the utility of the Sexual Function Questionnaire Medical Impact Scale (SFQ-MIS) in assessing impact of childbirth on sexual function among first-time mothers with infants aged one year or younger. A total of 255 women completed a cross-sectional, web-based survey. Exploratory factor analysis was utilized to assess the factor structure of the SFQ-MIS scores in this sample. Variations in SFQ-MIS scores based upon participant characteristics were conducted to further evaluate the SFQ-MIS scores. SFQ-MIS score was the primary measure of interest. Factors related to pregnancy and childbirth, such as mode of delivery, infant date of birth, last menstrual period, need for an episiotomy or perineal stitches, breastfeeding status, and score on the Perceived Stress Scale, were also assessed in order to further evaluate the validity and predictive capacity of the SFQ-MIS. Results indicated one factor that accounted for 58.27% of the variance in impact on sexual function due to childbirth. Cronbach's α coefficient for all five items was acceptable (0.82). Women who were breastfeeding (P<0.05), those who had received perineal stitches after a vaginal delivery (P<0.05), and those who reported no sexual activity in the past month (P < 0.001) experienced significantly greater impact than those who were not breastfeeding, those who had not required stitches, and those who had been sexually active in the past month. The SFQ-MIS appears to be a useful and valid indicator of changes in sexual function following childbirth, such as those related to arousal, desire, and orgasm. © 2013 International Society for Sexual Medicine.

Development of Rapid Pipe Moulding Process for Carbon Fiber Reinforced Thermoplastics by Direct Resistance Heating

NASA Astrophysics Data System (ADS)

Tanaka, Kazuto; Harada, Ryuki; Uemura, Toshiki; Katayama, Tsutao; Kuwahara, Hideyuki

To deal with environmental issues, the gasoline mileage of passenger cars can be improved by reduction of the car weight. The use of car components made of Carbon Fiber Reinforced Plastics (CFRP) is increasing because of its superior mechanical properties and relatively low density. Many vehicle structural parts are pipe-shaped, such as suspension arms, torsion beams, door guard bars and impact beams. A reduction of the car weight is expected by using CFRP for these parts. Especially, when considering the recyclability and ease of production, Carbon Fiber Reinforced Thermoplastics are a prime candidate. On the other hand, the moulding process of CFRTP pipes for mass production has not been well established yet. For this pipe moulding process an induction heating method has been investigated already, however, this method requires a complicated coil system. To reduce the production cost, another system without such complicated equipment is to be developed. In this study, the pipe moulding process of CFRTP using direct resistance heating was developed. This heating method heats up the mould by Joule heating using skin effect of high-frequency current. The direct resistance heating method is desirable from a cost perspective, because this method can heat the mould directly without using any coils. Formerly developed Non-woven Stitched Multi-axial Cloth (NSMC) was used as semi-product material. NSMC is very suitable for the lamination process due to the fact that non-crimp stitched carbon fiber of [0°/+45°/90°/-45°] and polyamide 6 non-woven fabric are stitched to one sheet, resulting in a short production cycle time. The use of the pipe moulding process with the direct resistance heating method in combination with the NSMC, has resulted in the successful moulding of a CFRTP pipe of 300 mm in length, 40 mm in diameter and 2 mm in thickness.

Initial load-to-failure and failure analysis in single- and double-row repair techniques for rotator cuff repair

PubMed Central

Buchhorn, G. H.; Gilbert, F.; Spahn, G.; Schultz, W.; Klinger, H.-M.

2010-01-01

Aim This experimental study aimed to compare the load-to-failure rate and stiffness of single- versus double-row suture techniques for repairing rotator cuff lesions using two different suture materials. Additionally, the mode of failure of each repair was evaluated. Method In 32 sheep shoulders, a standardized tear of the infraspinatus tendon was created. Then, n = 8 specimen were randomized to four repair methods: (1) Double-row Anchor Ethibond® coupled with polyester sutures, USP No. 2; (2) Double-Row Anchor HiFi® with polyblend polyethylene sutures, USP No. 2; (3) Single-Row Anchor Ethibond® coupled with braided polyester sutures, USP No. 2; and (4) Single-Row Anchor HiFi® with braided polyblend polyethylene sutures, USP No. 2. Arthroscopic Mason–Allen stitches were placed (single-row) and combined with medial horizontal mattress stitches (double-row). All specimens were loaded to failure at a constant displacement rate on a material testing machine. Results Group 4 showed lowest load-to-failure result with 155.7 ± 31.1 N compared to group 1 (293.4 ± 16.1 N) and group 2 (397.7 ± 7.4 N) (P < 0.001). Stiffness was highest in group 2 (162 ± 7.3 N/mm) and lowest in group 4 (84.4 ± 19.9 mm) (P < 0.001). In group 4, the main cause of failure was due to the suture cutting through the tendon (n = 6), a failure case observed in only n = 1 specimen in group 2 (P < 0.001). Conclusions A double-row technique combined with arthroscopic Mason-Allen/horizontal mattress stitches provides high initial failure strength and may minimize the risk of the polyethylene sutures cutting through the tendon in rotator cuff repair when a single load force is used. PMID:20049605

Application of Laser Based Ultrasound for NDE of Damage in Thick Stitched Composites

NASA Technical Reports Server (NTRS)

Anastasi, Robert F.; Friedman, Adam D.; Hinders, Mark K.; Madaras, Eric I.

1997-01-01

As design engineers implement new composite systems such as thick, load bearing composite structures, they must have certifiable confidence in structure s durability and worthiness. This confidence builds from understanding the structural response and failure characteristics of simple components loaded in testing machines to tests on full scale sections. Nondestructive evaluation is an important element which can provide quantitative information on the damage initiation, propagation, and final failure modes for the composite structural components. Although ultrasound is generally accepted as a test method, the use of conventional ultrasound for in-situ monitoring of damage during tests of large structures is not practical. The use of lasers to both generate and detect ultrasound extends the application of ultrasound to in- situ sensing of damage in a deformed structure remotely and in a non-contact manner. The goal of the present research is to utilize this technology to monitor damage progression during testing. The present paper describes the application of laser based ultrasound to quantify damage in thick stitched composite structural elements to demonstrate the method. This method involves using a Q-switched laser to generate a rapid, local linear thermal strain on the surface of the structure. This local strain causes the generation of ultrasonic waves into the material. A second laser used with a Fabry-Perot interferometer detects the surface deflections. The use of fiber optics provides for eye safety and a convenient method of delivering the laser over long distances to the specimens. The material for these structural elements is composed of several stacks of composite material assembled together by stitching through the laminate thickness that ranging from 0.5 to 0.8 inches. The specimens used for these nondestructive evaluation studies had either impact damage or skin/stiffener interlaminar failure. Although little or no visible surface damage existed, internal damage was detected by laser based ultrasound.

Multi-Depth-Map Raytracing for Efficient Large-Scene Reconstruction.

PubMed

Arikan, Murat; Preiner, Reinhold; Wimmer, Michael

2016-02-01

With the enormous advances of the acquisition technology over the last years, fast processing and high-quality visualization of large point clouds have gained increasing attention. Commonly, a mesh surface is reconstructed from the point cloud and a high-resolution texture is generated over the mesh from the images taken at the site to represent surface materials. However, this global reconstruction and texturing approach becomes impractical with increasing data sizes. Recently, due to its potential for scalability and extensibility, a method for texturing a set of depth maps in a preprocessing and stitching them at runtime has been proposed to represent large scenes. However, the rendering performance of this method is strongly dependent on the number of depth maps and their resolution. Moreover, for the proposed scene representation, every single depth map has to be textured by the images, which in practice heavily increases processing costs. In this paper, we present a novel method to break these dependencies by introducing an efficient raytracing of multiple depth maps. In a preprocessing phase, we first generate high-resolution textured depth maps by rendering the input points from image cameras and then perform a graph-cut based optimization to assign a small subset of these points to the images. At runtime, we use the resulting point-to-image assignments (1) to identify for each view ray which depth map contains the closest ray-surface intersection and (2) to efficiently compute this intersection point. The resulting algorithm accelerates both the texturing and the rendering of the depth maps by an order of magnitude.

10000 pixels wide CMOS frame imager for earth observation from a HALE UAV

NASA Astrophysics Data System (ADS)

Delauré, B.; Livens, S.; Everaerts, J.; Kleihorst, R.; Schippers, Gert; de Wit, Yannick; Compiet, John; Banachowicz, Bartosz

2009-09-01

MEDUSA is the lightweight high resolution camera, designed to be operated from a solar-powered Unmanned Aerial Vehicle (UAV) flying at stratospheric altitudes. The instrument is a technology demonstrator within the Pegasus program and targets applications such as crisis management and cartography. A special wide swath CMOS imager has been developed by Cypress Semiconductor Cooperation Belgium to meet the specific sensor requirements of MEDUSA. The CMOS sensor has a stitched design comprising a panchromatic and color sensor on the same die. Each sensor consists of 10000*1200 square pixels (5.5μm size, novel 6T architecture) with micro-lenses. The exposure is performed by means of a high efficiency snapshot shutter. The sensor is able to operate at a rate of 30fps in full frame readout. Due to a novel pixel design, the sensor has low dark leakage of the memory elements (PSNL) and low parasitic light sensitivity (PLS). Still it maintains a relative high QE (Quantum efficiency) and a FF (fill factor) of over 65%. It features an MTF (Modulation Transfer Function) higher than 60% at Nyquist frequency in both X and Y directions The measured optical/electrical crosstalk (expressed as MTF) of this 5.5um pixel is state-of-the art. These properties makes it possible to acquire sharp images also in low-light conditions.

Stitching Codeable Circuits: High School Students' Learning about Circuitry and Coding with Electronic Textiles

ERIC Educational Resources Information Center

Litts, Breanne K.; Kafai, Yasmin B.; Lui, Debora A.; Walker, Justice T.; Widman, Sari A.

2017-01-01

Learning about circuitry by connecting a battery, light bulb, and wires is a common activity in many science classrooms. In this paper, we expand students' learning about circuitry with electronic textiles, which use conductive thread instead of wires and sewable LEDs instead of lightbulbs, by integrating programming sensor inputs and light…

A Stitch in Time: Gender Issues Explored through Contemporary Textiles Practice in a Sixth Form College

ERIC Educational Resources Information Center

Hyde, Wendy

2007-01-01

This article discusses, contextualises and locates in contemporary theory, an autobiographical case study of an artist-teacher in the "learning community" of a Sixth Form College art department. It reflects on the educational potential of enabling teachers of art and their students to investigate issues of culture and identity through engaging…

Polymer infiltration studies

NASA Technical Reports Server (NTRS)

Marchello, Joseph M.

1992-01-01

The preparation is reported of carbon fiber composites using advanced polymer resins. Current and ongoing research activities include: powder towpreg process; weaving, braiding and stitching dry powder prepreg; advanced tow placement; and customized ATP towpreg. The goal of these studies is to produce advanced composite materials for automated part fabrication using textile and robotics technology in the manufacture of subsonic and supersonic aircraft.

Movidas Rascuaches: Strategies of Migrant Resistance at the Mexico-U.S. Border

ERIC Educational Resources Information Center

Spener, David

2010-01-01

In the field of Chicana/o arts and letters, "rasquachismo" refers to the celebration of the sensibility of "los de abajo" (the underdogs), whose resourcefulness and ingenuity permit them to overcome adversity by stitching together the tools needed to survive from whatever materials they have at hand. In this article, I apply…

(DCT-FY08) Target Detection Using Multiple Modality Airborne and Ground Based Sensors

DTIC Science & Technology

2013-03-01

Plenoptic modeling: an image-based rendering system,” in SIGGRAPH ’95: Proceedings of the 22nd annual conference on Computer graphics and interactive...techniques. New York, NY, USA: ACM, 1995, pp. 39–46. [21] D. G. Aliaga and I. Carlbom, “ Plenoptic stitching: a scalable method for reconstructing 3D

Students Combine Studies with Stethoscopes | Poster

Cancer.gov

By Nancy Parrish, Staff Writer Janine Bahsali and Esther Shafer are Middletown High School seniors who go to school in the morning and spend their afternoons taking blood pressure, assisting with physical exams, learning how to draw a blood sample and stitch a wound closed, and generally assisting the staff of Occupational Health Services (OHS), a health care department

A Stitch in Time: Strategic Self-Control in High School and College Students

ERIC Educational Resources Information Center

Duckworth, Angela L.; White, Rachel E.; Matteucci, Alyssa J.; Shearer, Annie; Gross, James J.

2016-01-01

A growing body of research indicates that self-control is critical to academic success. Surprisingly little is known, however, about the diverse strategies students use to implement self-control or how well these strategies work. To address these issues, the author conducted a naturalistic investigation of self-control strategies (Study 1) and 2…

Diversions: Writing the Alphabet Using Dots, Pixillated Alphanumerics, and Cross-Stitch

ERIC Educational Resources Information Center

Gough, John

2017-01-01

When computers started having screens (or monitors), as well as printers, a new alphanumeric display was created using dots. A crucial variable in designing alphabet letters and digits, using dots, is the height of the display, measured in dots. This article addresses the same design questions tackled by designers of typefaces or fonts, and shows…

Selections from the ABC 2014 Annual Convention, Philadelphia, Pennsylvania A Well-Stitched Banner of Favorite Assignments: Leadership and Other-Focused Communication and Projects

ERIC Educational Resources Information Center

Whalen, D. Joel

2015-01-01

This article, the second of a two-part series, features 11 teaching innovations presented at the 2014 Association for Business Communication annual conference. These 11 assignments included leadership and other-focused communication--detecting communication style, adaptive communication, personality type, delivering feedback, problem solving, and…

46 CFR 160.048-4 - Construction and workmanship.

Code of Federal Regulations, 2010 CFR

2010-10-01

... cover material will be allowed provided it is for decorative purposes only. Gusset or boxing materials..., boxing or gusset, they shall be attached by a double row of stitching of the type shown in Federal... permitted for the cover, but the boxing or gusset shall be a cotton fabric as specified by § 160.048-3(c)(1...

Projection Exposure with Variable Axis Immersion Lenses: A High-Throughput Electron Beam Approach to “Suboptical” Lithography

NASA Astrophysics Data System (ADS)

Pfeiffer, Hans

1995-12-01

IBM's high-throughput e-beam stepper approach PRojection Exposure with Variable Axis Immersion Lenses (PREVAIL) is reviewed. The PREVAIL concept combines technology building blocks of our probe-forming EL-3 and EL-4 systems with the exposure efficiency of pattern projection. The technology represents an extension of the shaped-beam approach toward massively parallel pixel projection. As demonstrated, the use of variable-axis lenses can provide large field coverage through reduction of off-axis aberrations which limit the performance of conventional projection systems. Subfield pattern sections containing 107 or more pixels can be electronically selected (mask plane), projected and positioned (wafer plane) at high speed. To generate the entire chip pattern subfields must be stitched together sequentially in a combination of electronic and mechanical positioning of mask and wafer. The PREVAIL technology promises throughput levels competitive with those of optical steppers at superior resolution. The PREVAIL project is being pursued to demonstrate the viability of the technology and to develop an e-beam alternative to “suboptical” lithography.

New optoelectronic methodology for nondestructive evaluation of MEMS at the wafer level

NASA Astrophysics Data System (ADS)

Furlong, Cosme; Ferguson, Curtis F.; Melson, Michael J.

2004-02-01

One of the approaches to fabrication of MEMS involves surface micromachining to define dies on single crystal silicon wafers, dicing of the wafers to separate the dies, and electronic packaging of the individual dies. Dicing and packaging of MEMS accounts for a large fraction of the fabrication costs, therefore, nondestructive evaluation at the wafer level, before dicing, can have significant implications on improving production yield and costs. In this paper, advances in development of optoelectronic holography (OEH) techniques for nondestructive, noninvasive, full-field of view evaluation of MEMS at the wafer level are described. With OEH techniques, quantitative measurements of shape and deformation of MEMS, as related to their performance and integrity, are obtained with sub-micrometer spatial resolution and nanometer measuring accuracy. To inspect an entire wafer with OEH methodologies, measurements of overlapping regions of interest (ROI) on a wafer are recorded and adjacent ROIs are stitched together through efficient 3D correlation analysis algorithms. Capabilities of the OEH techniques are illustrated with representative applications, including determination of optimal inspection conditions to minimize inspection time while achieving sufficient levels of accuracy and resolution.

Flexible Composite-Material Pressure Vessel

NASA Technical Reports Server (NTRS)

Brown, Glen; Haggard, Roy; Harris, Paul A.

2003-01-01

A proposed lightweight pressure vessel would be made of a composite of high-tenacity continuous fibers and a flexible matrix material. The flexibility of this pressure vessel would render it (1) compactly stowable for transport and (2) more able to withstand impacts, relative to lightweight pressure vessels made of rigid composite materials. The vessel would be designed as a structural shell wherein the fibers would be predominantly bias-oriented, the orientations being optimized to make the fibers bear the tensile loads in the structure. Such efficient use of tension-bearing fibers would minimize or eliminate the need for stitching and fill (weft) fibers for strength. The vessel could be fabricated by techniques adapted from filament winding of prior composite-material vessels, perhaps in conjunction with the use of dry film adhesives. In addition to the high-bias main-body substructure described above, the vessel would include a low-bias end substructure to complete coverage and react peak loads. Axial elements would be overlaid to contain damage and to control fiber orientation around side openings. Fiber ring structures would be used as interfaces for connection to ancillary hardware.

Underwater image mosaicking and visual odometry

NASA Astrophysics Data System (ADS)

Sadjadi, Firooz; Tangirala, Sekhar; Sorber, Scott

2017-05-01

This paper summarizes the results of studies in underwater odometery using a video camera for estimating the velocity of an unmanned underwater vehicle (UUV). Underwater vehicles are usually equipped with sonar and Inertial Measurement Unit (IMU) - an integrated sensor package that combines multiple accelerometers and gyros to produce a three dimensional measurement of both specific force and angular rate with respect to an inertial reference frame for navigation. In this study, we investigate the use of odometry information obtainable from a video camera mounted on a UUV to extract vehicle velocity relative to the ocean floor. A key challenge with this process is the seemingly bland (i.e. featureless) nature of video data obtained underwater which could make conventional approaches to image-based motion estimation difficult. To address this problem, we perform image enhancement, followed by frame to frame image transformation, registration and mosaicking/stitching. With this approach the velocity components associated with the moving sensor (vehicle) are readily obtained from (i) the components of the transform matrix at each frame; (ii) information about the height of the vehicle above the seabed; and (iii) the sensor resolution. Preliminary results are presented.

Assessing Microneurosurgical Skill with Medico-Engineering Technology.

PubMed

Harada, Kanako; Morita, Akio; Minakawa, Yoshiaki; Baek, Young Min; Sora, Shigeo; Sugita, Naohiko; Kimura, Toshikazu; Tanikawa, Rokuya; Ishikawa, Tatsuya; Mitsuishi, Mamoru

2015-10-01

Most methods currently used to assess surgical skill are rather subjective or not adequate for microneurosurgery. Objective and quantitative microneurosurgical skill assessment systems that are capable of accurate measurements are necessary for the further development of microneurosurgery. Infrared optical motion tracking markers, an inertial measurement unit, and strain gauges were mounted on tweezers to measure many parameters related to instrument manipulation. We then recorded the activity of 23 neurosurgeons. The task completion time, tool path, and needle-gripping force were evaluated for three stitches made in an anastomosis of 0.7-mm artificial blood vessels. Videos of the activity were evaluated by three blinded expert surgeons. Surgeons who had recently done many bypass procedures demonstrated better skills. These skilled surgeons performed the anastomosis with in a shorter time, with a shorter tool path, and with a lesser force when extracting the needle. These results show the potential contribution of the system to microsurgical skill assessment. Quantitative and detailed analysis of surgical tasks helps surgeons better understand the key features of the required skills. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Team Sports: A Place for Primary Care

PubMed Central

Hancock, Larry

1985-01-01

Physicians' role in team sports goes beyond the traditional ‘Doc’ who attends the game for stitching and primary injury management. Injury and illness prevention, ongoing supervision of rehabilitation, education, fitness evaluation, and training prescription are roles which have often fallen, by default, to paramedicals. The author recounts his experience in medical supervision of major junior hockey in the Western Hockey League. PMID:21274088

STS-118 Ascent/Entry Flight Control Team in White Flight Control Room (WFCR) with Flight Director Steve Stitch

NASA Image and Video Library

2007-07-20

JSC2007-E-41011 (20 July 2007) --- STS-118 Ascent/Entry flight control team pose for a group portrait in the space shuttle flight control room of Houston's Mission Control Center (MCC). Flight director Steve Stich (center right) and astronaut Tony Antonelli, spacecraft communicator (CAPCOM), hold the STS-118 mission logo.

Guidelines for Developing and Inserting Material Properties into the Code 65 Composite Material Database

DTIC Science & Technology

2011-12-01

kind of base fiber used Fab-ric uni, stitched, weave, woven roving, textile form, tape, prepreg Laminate Schedu le [0]10 [0]14 [0]36 Manufacturing...roving, textile form, tape, prepreg Laminate Schedule [0]10 [0]14 [0]36 Manufacturing Date 2006 Test Facility/Date 2007 Program of Record AHM&ST...9 Laminate Schedule .......................................................................................................10 Cure

Panoramic optical-servoing for industrial inspection and repair

NASA Astrophysics Data System (ADS)

Sallinger, Christian; O'Leary, Paul; Retschnig, Alexander; Kammerhofer, Martin

2004-05-01

Recently specialized robots were introduced to perform the task of inspection and repair in large cylindrical structures such as ladles, melting furnaces and converters. This paper reports on the image processing system and optical servoing for one such a robot. A panoramic image of the vessels inner surface is produced by performing a coordinated robot motion and image acquisition. The level of projective distortion is minimized by acquiring a high density of images. Normalized phase correlation calculated via the 2D Fourier transform is used to calculate the shift between the single images. The narrow strips from the dense image map are then stitched together to build the panorama. The mapping between the panoramic image and the positioning of the robot is established during the stitching of the images. This enables optical feedback. The robots operator can locate a defect on the surface by selecting the area of the image. Calculation of the forward and inverse kinematics enable the robot to automatically move to the location on the surface requiring repair. Experimental results using a standard 6R industrial robot have shown the full functionality of the system concept. Finally, were test measurements carried out successfully, in a ladle at a temperature of 1100° C.

Weighted spline based integration for reconstruction of freeform wavefront.

PubMed

Pant, Kamal K; Burada, Dali R; Bichra, Mohamed; Ghosh, Amitava; Khan, Gufran S; Sinzinger, Stefan; Shakher, Chandra

2018-02-10

In the present work, a spline-based integration technique for the reconstruction of a freeform wavefront from the slope data has been implemented. The slope data of a freeform surface contain noise due to their machining process and that introduces reconstruction error. We have proposed a weighted cubic spline based least square integration method (WCSLI) for the faithful reconstruction of a wavefront from noisy slope data. In the proposed method, the measured slope data are fitted into a piecewise polynomial. The fitted coefficients are determined by using a smoothing cubic spline fitting method. The smoothing parameter locally assigns relative weight to the fitted slope data. The fitted slope data are then integrated using the standard least squares technique to reconstruct the freeform wavefront. Simulation studies show the improved result using the proposed technique as compared to the existing cubic spline-based integration (CSLI) and the Southwell methods. The proposed reconstruction method has been experimentally implemented to a subaperture stitching-based measurement of a freeform wavefront using a scanning Shack-Hartmann sensor. The boundary artifacts are minimal in WCSLI which improves the subaperture stitching accuracy and demonstrates an improved Shack-Hartmann sensor for freeform metrology application.

Absence of posterior tricuspid valve leaflet and valve reconstruction

PubMed Central

Komoda, Takeshi; Stamm, Christof; Fleck, Eckart; Hetzer, Roland

2012-01-01

We report a rare case of the absence of a posterior tricuspid valve leaflet. A male patient, aged 46, suffering from severe tricuspid valve regurgitation (TR) of unknown aetiology and atrial septal aneurysm was referred to our hospital for surgery. On surgical inspection, the posterior tricuspid valve leaflet and its subvalvular apparatus were completely absent and only the valve annulus was seen in the corresponding position. The anterior and septal leaflets were normal. We successfully reconstructed the tricuspid valve as follows: the head of an anterior papillary muscle was approximated to the ventricular septum (Sebening stitch). After the approximation of the centre of the tricuspid annulus of the anterior leaflet to the tricuspid annulus on the opposite side, a sizer of 29 mm in diameter was easily passed through the anterior orifice. The posterior orifice was closed with running sutures (posterior annulorrhaphy after Hetzer). Before these procedures, we attempted to reconstruct the tricuspid valve with a posterior annulorrhaphy alone; however, valve competence was insufficient. A Sebening stitch was necessary to improve the valve competence. Echocardiography showed TR grade 1 at the patient's discharge from hospital and TR grade 1 to 2 at the follow-up, 10 months after the operation. PMID:22419794

Compression response of thick layer composite laminates with through-the-thickness reinforcement

NASA Technical Reports Server (NTRS)

Farley, Gary L.; Smith, Barry T.; Maiden, Janice

1992-01-01

Compression and compression-after-impact (CAI) tests were conducted on seven different AS4-3501-6 (0/90) 0.64-cm thick composite laminates. Four of the seven laminates had through-the-thickness (TTT) reinforcement fibers. Two TTT reinforcement methods, stitching and integral weaving, and two reinforcement fibers, Kevlar and carbon, were used. The remaining three laminates were made without TTT reinforcements and were tested to establish a baseline for comparison with the laminates having TTT reinforcement. Six of the seven laminates consisted of nine thick layers whereas the seventh material was composed of 46 thin plies. The use of thick-layer material has the potential for reducing structural part cost because of the reduced part count (layers of material). The compression strengths of the TTT reinforced laminates were approximately one half those of the materials without TTT reinforcements. However, the CAI strengths of the TTT reinforced materials were approximately twice those of materials without TTT reinforcements. The improvement in CAI strength is due to an increase in interlaminar strength produced by the TTT reinforcement. Stitched laminates had slightly higher compression and CAI strengths than the integrally woven laminates.

Modified arthroscopic suture fixation of a displaced tibial eminence fracture.

PubMed

Lehman, Ronald A; Murphy, Kevin P; Machen, M Shaun; Kuklo, Timothy R

2003-02-01

This study describes a new arthroscopic method using a whip-stitch technique for treating a displaced type III tibial eminence fracture. A 12-year-old girl who sustained a displaced type III tibial eminence fracture was treated with arthroscopic fixation using the Arthrosew disposable suture device (Surgical Dynamics, Norwalk, CT) to place a whip stitch into the anterior cruciate ligament (ACL). The Arthrex ACL guide (Arthrex, Naples, FL) was used to reduce the avulsed tibial spine fragment. Sutures were then passed through the tibial tunnel and secured over a bony bridge with the knee in 20 degrees of flexion. At 9 months, the patient has a full range of motion with normal Lachman and anterior drawer testing, and she has returned to competitive basketball. Radiographs show complete fracture healing. KT-1000 and isokinetic testing at 9-month follow-up show only minimal side-to-side differences. The Arthrosew device provides a significant advantage in the treatment of type III and IV fractures of the tibial eminence by obtaining arthroscopic fixation within the substance of the ACL, thus obviating arthrotomy and hardware placement. This technique also restores the proper length and tension to the ACL, and provides a simplified, reproducible method of treatment for this injury.

[Abdominal wall reconstruction with collagen membrane in an animal model of abdominal hernia. A preliminary report].

PubMed

Łukasiewicz, Aleksander; Drewa, Tomasz; Skopińska-Wiśniewska, Joanna; Molski, Stanisław

2008-01-01

Abdominal hernia repair is one of the most common surgical procedures. Current data indicate that the best treatment results are achieved with use of synthetic material to reinforce weakened abdominal wall. Prosthetic materials utilized for hernia repair induce adhesions with underlying viscera. They should be therefore separated from them by a layer of peritoneum otherwise adhesions may cause to serious complications such as bowel-skin fistulas. The aim of our work was to determine if implantation of our collagen membrane into abdominal wall defect induce adhesions in rat model of ventral hernia. The collagen film was obtained by acetic acid extraction of rat tail tendons and than casting the soluble fraction onto polyethylene shits. Abdominal wall defect was created in 10 Wistar male rats. Collagen membranes were implanted into the defect using interrupted polypropylene stitches. After 3 months of observation all animals were sacrificed. No adhesions between path structure and bowel developed. In one often rats (10%) adhesion between fixating stitch and omentum was observed. Complete mesothelium lining and vascular ingrowth were microscopically observed within implanted structure. Promising result requires further confirmation in a larger series of animals.

Constructing spherical panoramas of a bladder phantom from endoscopic video using bundle adjustment

NASA Astrophysics Data System (ADS)

Soper, Timothy D.; Chandler, John E.; Porter, Michael P.; Seibel, Eric J.

2011-03-01

The high recurrence rate of bladder cancer requires patients to undergo frequent surveillance screenings over their lifetime following initial diagnosis and resection. Our laboratory is developing panoramic stitching software that would compile several minutes of cystoscopic video into a single panoramic image, covering the entire bladder, for review by an urolgist at a later time or remote location. Global alignment of video frames is achieved by using a bundle adjuster that simultaneously recovers both the 3D structure of the bladder as well as the scope motion using only the video frames as input. The result of the algorithm is a complete 360° spherical panorama of the outer surface. The details of the software algorithms are presented here along with results from both a virtual cystoscopy as well from real endoscopic imaging of a bladder phantom. The software successfully stitched several hundred video frames into a single panoramic with subpixel accuracy and with no knowledge of the intrinsic camera properties, such as focal length and radial distortion. In the discussion, we outline future work in development of the software as well as identifying factors pertinent to clinical translation of this technology.

Aerodynamics of sports balls

NASA Astrophysics Data System (ADS)

Mehta, R. D.

Research data on the aerodynamic behavior of baseballs and cricket and golf balls are summarized. Cricket balls and baseballs are roughly the same size and mass but have different stitch patterns. Both are thrown to follow paths that avoid a batter's swing, paths that can curve if aerodynamic forces on the balls' surfaces are asymmetric. Smoke tracer wind tunnel tests and pressure taps have revealed that the unbalanced side forces are induced by tripping the boundary layer on the seam side and producing turbulence. More particularly, the greater pressures are perpendicular to the seam plane and only appear when the balls travel at velocities high enough so that the roughness length matches the seam heigh. The side forces, once tripped, will increase with spin velocity up to a cut-off point. The enhanced lift coefficient is produced by the Magnus effect. The more complex stitching on a baseball permits greater variations in the flight path curve and, in the case of a knuckleball, the unsteady flow effects. For golf balls, the dimples trip the boundary layer and the high spin rate produces a lift coefficient maximum of 0.5, compared to a baseball's maximum of 0.3. Thus, a golf ball travels far enough for gravitational forces to become important.

Aerodynamics of sports balls

NASA Technical Reports Server (NTRS)

Mehta, R. D.

1985-01-01

Research data on the aerodynamic behavior of baseballs and cricket and golf balls are summarized. Cricket balls and baseballs are roughly the same size and mass but have different stitch patterns. Both are thrown to follow paths that avoid a batter's swing, paths that can curve if aerodynamic forces on the balls' surfaces are asymmetric. Smoke tracer wind tunnel tests and pressure taps have revealed that the unbalanced side forces are induced by tripping the boundary layer on the seam side and producing turbulence. More particularly, the greater pressures are perpendicular to the seam plane and only appear when the balls travel at velocities high enough so that the roughness length matches the seam heigh. The side forces, once tripped, will increase with spin velocity up to a cut-off point. The enhanced lift coefficient is produced by the Magnus effect. The more complex stitching on a baseball permits greater variations in the flight path curve and, in the case of a knuckleball, the unsteady flow effects. For golf balls, the dimples trip the boundary layer and the high spin rate produces a lift coefficient maximum of 0.5, compared to a baseball's maximum of 0.3. Thus, a golf ball travels far enough for gravitational forces to become important.

Yellow River Icicle Hazard Dynamic Monitoring Using UAV Aerial Remote Sensing Technology

NASA Astrophysics Data System (ADS)

Wang, H. B.; Wang, G. H.; Tang, X. M.; Li, C. H.

2014-02-01

Monitoring the response of Yellow River icicle hazard change requires accurate and repeatable topographic surveys. A new method based on unmanned aerial vehicle (UAV) aerial remote sensing technology is proposed for real-time data processing in Yellow River icicle hazard dynamic monitoring. The monitoring area is located in the Yellow River ice intensive care area in southern BaoTou of Inner Mongolia autonomous region. Monitoring time is from the 20th February to 30th March in 2013. Using the proposed video data processing method, automatic extraction covering area of 7.8 km2 of video key frame image 1832 frames took 34.786 seconds. The stitching and correcting time was 122.34 seconds and the accuracy was better than 0.5 m. Through the comparison of precise processing of sequence video stitching image, the method determines the change of the Yellow River ice and locates accurate positioning of ice bar, improving the traditional visual method by more than 100 times. The results provide accurate aid decision information for the Yellow River ice prevention headquarters. Finally, the effect of dam break is repeatedly monitored and ice break five meter accuracy is calculated through accurate monitoring and evaluation analysis.

Analysis of the fluid mechanical sewing machine

NASA Astrophysics Data System (ADS)

Brun, Pierre-Thomas; Audoly, Basile; Ribe, Neil

2012-02-01

A thin thread of viscous fluid falling onto a moving belt generates a surprising variety of patterns, similar to the stitch patterns produced by a traditional sewing machine. By simulating the dynamics of the viscous thread numerically, we can reproduce these patterns and their bifurcations. The results lead us to propose a new classification of the stitch patterns within a unified framework, based on the Fourier spectra of the motion of the point of contact of the thread with the belt. The frequencies of the longitudinal and transverse components of the contact point motion are locked in most cases to simple ratios of the frequency φc of steady coiling on a surface at rest (i.e., the limit of zero belt speed). In particular, the ``alternating loops'' pattern involves the first five multiples of φc/3. The dynamics of the patterns can be described by matching the upper (linear) and the lower (non-linear) portions of the thread. Following this path we propose a toy model that successfully reproduces the observed transitions from the steady dragged configuration to sinusoidal meanders, alternating loops, and the translated coiling pattern as the belt speed is varied.

Global and Local Stress Analyses of McDonnell Douglas Stitched/RFI Composite Wing Stub Box

NASA Technical Reports Server (NTRS)

Wang, John T.

1996-01-01

This report contains results of structural analyses performed in support of the NASA structural testing of an all-composite stitched/RFI (resin film infusion) wing stub box. McDonnell Douglas Aerospace Company designed and fabricated the wing stub box. The analyses used a global/local approach. The global model contains the entire test article. It includes the all-composite stub box, a metallic load-transition box and a metallic wing-tip extension box. The two metallic boxes are connected to the inboard and outboard ends of the composite wing stub box, respectively. The load-transition box was attached to a steel and concrete vertical reaction structure and a load was applied at the tip of the extension box to bend the wing stub box upward. The local model contains an upper cover region surrounding three stringer runouts. In that region, a large nonlinear deformation was identified by the global analyses. A more detailed mesh was used for the local model to obtain more accurate analysis results near stringer runouts. Numerous analysis results such as deformed shapes, displacements at selected locations, and strains at critical locations are included in this report.

Authentic Learning Experiences for Educators through Summer Internships: Revising the DIG Texas Instructional Blueprints

NASA Astrophysics Data System (ADS)

Martinez, A. O.; Bohls-Graham, E.; Jacobs, B. E.; Ellins, K. K.

2014-12-01

Texas teachers have expressed a need for engaging activities for use in high school Earth science courses. With funding from the NSF, geoscience and education faculty from different institutions around the state collaborated with ten Earth science teachers to create five online Earth science instructional blueprints. The work is part of the DIG (Diversity and Innovation for Geosciences) Texas Instructional Blueprint project. A blueprint stitches together nine units for a yearlong Earth science course (scope and sequence). Each unit covers three weeks of teaching and contains lectures, readings, visualizations, lab investigations, learning activities, and other educational materials from credible sources, which are aligned with Texas state science standards for Earth and Space Science and the Earth Science Literacy Principles. Taken together, the collection of activities address the Next Generation Science Standards (NGSS). During summer 2014, three minority-serving secondary teachers completed a six-week internship at The University of Texas Institute for Geophysics (UTIG). As DIG Texas Education Interns, we organized and revised the content of the units, created scaffolding notes, and built blueprints by selecting groups of nine units from the project's current collection of twenty-one units. Because fieldwork is an important element of geoscience learning, we integrated virtual field trips into each unit. We (1) gained expertise in selecting high quality activities that directly correlate with state standards and address the Earth Science Literacy Principles; (2) developed a keen awareness of the value of the NGSS; (3) learned how to navigate through the NGSS website to track the relationships between the Science and Engineering Practices, Disciplinary Core Ideas, and Crosscutting Concepts for Earth science, as well as connections to other disciplines in the same grade level. Collaborating with other secondary Earth science teachers introduced each of us to new teaching practices, allowing us to build relationships that we expect to last for many years. UTIG researchers mentored and introduced us to their research and methodology. In addition, they helped us find high quality activities for the units. In turn, we shared our knowledge of pedagogy and classroom expertise with them.

Nonlinear Finite Element Analysis of a Composite Non-Cylindrical Pressurized Aircraft Fuselage Structure

NASA Technical Reports Server (NTRS)

Przekop, Adam; Wu, Hsi-Yung T.; Shaw, Peter

2014-01-01

The Environmentally Responsible Aviation Project aims to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration are not sufficient to achieve the desired metrics. One of the airframe concepts that might dramatically improve aircraft performance is a composite-based hybrid wing body configuration. Such a concept, however, presents inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a nonlinear finite element analysis of a large-scale test article being developed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. There are specific reasons why geometrically nonlinear analysis may be warranted for the hybrid wing body flat panel structure. In general, for sufficiently high internal pressure and/or mechanical loading, energy related to the in-plane strain may become significant relative to the bending strain energy, particularly in thin-walled areas such as the minimum gage skin extensively used in the structure under analysis. To account for this effect, a geometrically nonlinear strain-displacement relationship is needed to properly couple large out-of-plane and in-plane deformations. Depending on the loading, this nonlinear coupling mechanism manifests itself in a distinct manner in compression- and tension-dominated sections of the structure. Under significant compression, nonlinear analysis is needed to accurately predict loss of stability and postbuckled deformation. Under significant tension, the nonlinear effects account for suppression of the out-of-plane deformation due to in-plane stretching. By comparing the present results with the previously published preliminary linear analysis, it is demonstrated in the present paper that neglecting nonlinear effects for the structure and loads of interest can lead to appreciable loss in analysis fidelity.

Impact of Medicare Advantage penetration and hospital competition on technical efficiency of nursing care in US intensive care units.

PubMed

Min, Ari; Scott, Linda D; Park, Chang; Vincent, Catherine; Ryan, Catherine J; Lee, Taewha

2018-04-10

This study aimed to evaluate technical efficiency of US intensive care units and determine the effects of environmental factors on technical efficiency in providing quality of nursing care. Data were obtained from the 2014 National Database of Nursing Quality Indicators and the Centers for Medicare and Medicaid Services. Data envelopment analysis was used to estimate technical efficiency for each intensive care unit. Multilevel modeling was used to determine the effects of environmental factors on technical efficiency. Overall, Medicare Advantage penetration and hospital competition in a market did not create pressure for intensive care units to become more efficient by reducing their inputs. However, these 2 environmental factors showed positive influences on technical efficiency in intensive care units with certain levels of technical efficiency. The implications of the study results for management strategies and health policy may vary according to the levels of technical efficiency in intensive care units. Further studies are needed to examine why and how intensive care units with particular levels of technical efficiency are differently affected by certain environmental factors. Copyright © 2018 John Wiley & Sons, Ltd.

Craft in America: A Journey to the Artists, Origins and Work of American Craft

ERIC Educational Resources Information Center

SchoolArts: The Art Education Magazine for Teachers, 2007

2007-01-01

Quilting, the tradition of stitching together layers of fabric and padding, probably began as a way to provide protection in clothing, but one most often associates quilts with the warmth and comfort of bedding. As so often happens with objects created for a particular purpose, quilts have come to be valued, not only for their function, but also…

Students Combine Studies with Stethoscopes | Poster

Cancer.gov

By Nancy Parrish, Staff Writer Janine Bahsali and Esther Shafer are Middletown High School seniors who go to school in the morning and spend their afternoons taking blood pressure, assisting with physical exams, learning how to draw a blood sample and stitch a wound closed, and generally assisting the staff of Occupational Health Services (OHS), a health care department serving more than 2,000 employees at NCI at Frederick.

Silviculture and nontimber forest products: extending the benefits of forest management

Treesearch

Marla R. Emery; John Zasada

2001-01-01

Jackie makes birch bark and sweet grass baskets, stitched with spruce root. Her work is so fine that a New England folklife institute has recognized her as a master basketmaker. Nora and Lawrence earn a very modest income selling mushrooms and other wild foods to upscale restaurants. A good part of their own food and medicine also comes from the woods, wetlands, and...

A Rhythmic Approach to Mathematics. Classics in Mathematics Education, Volume 5.

ERIC Educational Resources Information Center

Somervell, Edith L.

This book is a reproduction of a monograph written in 1906 to advocate the use of curve stitching in the early school years. The book was originally accompanied by a set of punched cards depicting geometric shapes; each card could be used in the construction of many varied designs. The book's preface is written by Mary Boole, to whom the technique…

An investigation into scalability and compliance for triple patterning with stitches for metal 1 at the 14nm node

NASA Astrophysics Data System (ADS)

Cork, Christopher; Miloslavsky, Alexander; Friedberg, Paul; Luk-Pat, Gerry

2013-04-01

Lithographers had hoped that single patterning would be enabled at the 20nm node by way of EUV lithography. However, due to delays in EUV readiness, double patterning with 193i lithography is currently relied upon for volume production for the 20nm node's metal 1 layer. At the 14nm and likely at the 10nm node, LE-LE-LE triple patterning technology (TPT) is one of the favored options [1,2] for patterning local interconnect and Metal 1 layers. While previous research has focused on TPT for contact mask, metal layers offer new challenges and opportunities, in particular the ability to decompose design polygons across more than one mask. The extra flexibility offered by the third mask and ability to leverage polygon stitching both serve to improve compliance. However, ensuring TPT compliance - the task of finding a 3-color mask decomposition for a design - is still a difficult task. Moreover, scalability concerns multiply the difficulty of triple patterning decomposition which is an NP-complete problem. Indeed previous work shows that network sizes above a few thousand nodes or polygons start to take significantly longer times to compute [3], making full chip decomposition for arbitrary layouts impractical. In practice Metal 1 layouts can be considered as two separate problem domains, namely: decomposition of standard cells and decomposition of IP blocks. Standard cells typically include only a few 10's of polygons and should be amenable to fast decomposition. Successive design iterations should resolve compliance issues and improve packing density. Density improvements are multiplied repeatedly as standard cells are placed multiple times. IP blocks, on the other hand, may involve very large networks. This paper evaluates multiple approaches to triple patterning decomposition for the Metal 1 layer. The benefits of polygon stitching, in particular, the ability to resolve commonly encountered non-compliant layout configurations and improve packing density, are weighed against the increased difficulty in finding an optimized, legal decomposition and coping with the increased scalability challenges.

Anatomical based registration of multi-sector x-ray images for panorama reconstruction

NASA Astrophysics Data System (ADS)

Ben-Zikri, Yehuda Kfir; Mendez, Stacy; Linte, Cristian A.

2017-03-01

Accurate measurement of long limb alignment is an essential stage of the pre-operative planning of realignment surgery. This alignment is quantified according to the hip-knee-ankle (HKA) angle of the mechanical axis of the lower extremity and is measured based on a full-length weight-bearing X-ray or standard computed radiography (CR) image of the patient in standing position. Due to the limited field-of-view of the traditionally employed digital X-ray imaging systems, several sector images are required to capture the posture of a standing individual. These sector images need to then be "stitched" together to reconstruct the standing posture. To eliminate user-induced variability and time constraints associated with the traditional manual "stitching" protocol, we have created an image processing application to automate the stitching process, when there are no reliable external markers available in the images, by only relying on the most reliable anatomical content of the image. The application starts with a rough segmentation of the tibia and the sector images are then registered by evaluating the DICE coefficient between the edges of these corresponding bones along the medial edge. The identified translations are then used to register the original sector images into the standing panorama image. To test the robustness of our method, we randomly selected 40 datasets from a variant database consisting of nearly 100 patient X-ray images acquired for patient screening as part of a multi-site clinical trial. The resulting horizontal and vertical translation values from the automated registration were compared to the homologous translations recorded during the manual panorama generation conducted by a knowledgeable X-ray imaging technician. The mean and standard deviation of the differences for the horizontal translation parameters was -0:27+/-1:14 mm and 0:31+/-1:86 mm for the left and right tibia, respectively. The vertical translation differences for the left and right tibia were 1:05+/-5:24 mm and 1:32+/-4:77 mm, respectively. For these differences, the expert radiologist reported no difference in the hip-knee-ankle angular assessment.

Creating a stakeholder-driven unified conservation blueprint for 15 southeastern states.

NASA Astrophysics Data System (ADS)

Hopkins, T. E.

2017-12-01

The dramatic changes sweeping the Southeastern United States — such as urbanization, competition for water resources, extreme weather events, sea-level rise, and climate change — pose unprecedented challenges for sustaining our natural and cultural resources. Defining the conservation landscape of the future requires a new model of working together across entities, factions, and political boundaries through a collaborative process. We will illustrate how ecosystem service valuation can be built using a stakeholder-drive process which has united the conservation community through a shared, long-term vision for the future through the Southeast Conservation Adaptation Strategy (SECAS). Through SECAS, diverse public and private partners have worked together to design and achieve a connected network of landscapes and seascapes that supports thriving fish and wildlife populations and improved quality of life for people across the southeastern U.S. and the Caribbean. The scope of SECAS is the fifteen southeastern states that comprise the Southeast Association of Fish and Wildlife Agencies (SEAFWA) plus Puerto Rico and the United States Virgin Islands. SECAS was initiated by SEAFWA and the federal Southeast Natural Resource Leaders Group with support from six Landscape Conservation Cooperatives (LCCs), the Southeast Climate Science Center, and the Southeast Aquatic Resources Partnership. In October of 2016, SECAS achieved a major milestone with the release of a first draft of a conservation blueprint for the Southeast and Caribbean. This blueprint stitches together the conservation and restoration priorities of multiple LCCs in the region into one unifying map — a living spatial plan to make the SECAS vision a reality. Whether you are an urban planner, a private landowner, a non-profit advocate, a public lands manager, or anyone else committed to sustaining our natural and cultural heritage for future generations, join the SECAS conversation at www.secassoutheast.org

MCT-Based LWIR and VLWIR 2D Focal Plane Detector Arrays for Low Dark Current Applications at AIM

NASA Astrophysics Data System (ADS)

Hanna, S.; Eich, D.; Mahlein, K.-M.; Fick, W.; Schirmacher, W.; Thöt, R.; Wendler, J.; Figgemeier, H.

2016-09-01

We present our latest results on n-on- p as well as on p-on- n low dark current planar mercury cadmium telluride (MCT) photodiode technology long wavelength infrared (LWIR) and very long wavelength infrared (VLWIR) two-dimensional focal plane arrays (FPAs) with quantum efficiency (QE) cut-off wavelength >11 μm at 80 K and a 512 × 640 pixel format FPA at 20 μm pitch stitched from two 512 × 320 pixel photodiode arrays. Significantly reduced dark currents as compared with Tennant's "Rule 07" are demonstrated in both polarities while retaining good detection efficiency ≥60% for operating temperatures between 30 K and 100 K. This allows for the same dark current performance at 20 K higher operating temperature than with previous AIM INFRAROT-MODULE GmbH (AIM) technology. For p-on- n LWIR MCT FPAs, broadband photoresponse nonuniformity of only about 1.2% is achieved at 55 K with low defective pixel numbers. For an n-on- p VLWIR MCT FPA with 13.6 μm cut-off at 55 K, excellent photoresponse nonuniformity of about 3.1% is achieved at moderate defective pixel numbers. This advancement in detector technology paves the way for outstanding signal-to-noise ratio performance infrared detection, enabling cutting-edge next-generation LWIR/VLWIR detectors for space instruments and devices with higher operating temperature and low size, weight, and power for field applications.

Advanced technology satellite demodulator development

NASA Technical Reports Server (NTRS)

Ames, Stephen A.

1989-01-01

Ford Aerospace has developed a proof-of-concept satellite 8 phase shift keying (PSK) modulation and coding system operating in the Time Division Multiple Access (TDMA) mode at a data range of 200 Mbps using rate 5/6 forward error correction coding. The 80 Msps 8 PSK modem was developed in a mostly digital form and is amenable to an ASIC realization in the next phase of development. The codec was developed as a paper design only. The power efficiency goal was to be within 2 dB of theoretical at a bit error rate (BER) of 5x10(exp 7) while the measured implementation loss was 4.5 dB. The bandwidth efficiency goal was 2 bits/sec/Hz while the realized bandwidth efficiency was 1.8 bits/sec/Hz. The burst format used a preamble of only 40 8 PSK symbol times including 32 symbols of all zeros and an eight symbol unique word. The modem and associated special test equipment (STE) were fabricated mostly on a specially designed stitch-weld board although a few of the highest rate circuits were built on printed circuit cards. All the digital circuits were ECL to support the clock rates of from 80 MHz to 360 MHz. The transmitter and receiver matched filters were square-root Nyquist bandpass filters realized at the 3.37 GHz i.f. The modem operated as a coherent system although no analog phase locked (PLL) loop was employed. Within the budgetary constraints of the program, the approach to the demodulator has been proven and is eligible to proceed to the next phase of development of a satellite demodulator engineering model. This would entail the development of an ASIC version of the digital portion of the demodulator, and MMIC version of the quadrature detector, and SAW Nyquist filters to realize the bandwidth efficiency.

Improved Image-Guided Laparoscopic Prostatectomy

DTIC Science & Technology

2012-08-01

prevalent technique used in widening the field of view (FOV) of medical ultrasound images. Also referred to as stitching or panorama , the ultra- sound mosaic...tissue which can add valu- able features to the B-mode panorama . Many clinical applications deal with large cancerous lesions which expand beyond the...1999) 203–233 2. Varghese, T., Zagzebski, J., Lee Jr., F.: Elastographic imaging of thermal lesions in the liver in vivo following radiofrequency

Image Processing for Cameras with Fiber Bundle Image Relay

DTIC Science & Technology

length. Optical fiber bundles have been used to couple between this focal surface and planar image sensors . However, such fiber-coupled imaging systems...coupled to six discrete CMOS focal planes. We characterize the locally space-variant system impulse response at various stages: monocentric lens image...vignetting, and stitch together the image data from discrete sensors into a single panorama. We compare processed images from the prototype to those taken with

Stability Thresholds and Performance Standards for Flexible Lining Materials in Channel and Slope Restoration Applications

DTIC Science & Technology

2012-07-01

common industry term Bioengineering - Structural applications using vegetation- seed, plants, live cuttings and/or wood NRCS, common industry term...downstream, the use of non-biodegradable products (geosynthetics, plastics , rebar, metal anchors, etc.) in natural settings, and limited benefits to or...entanglement until vegetation establishment and adherence of the TRM to the soil surface (ECTC 2008). Stitch- bonded, geosynthetic extruded and fused TRMs

Art Teaching Guides: Using Cloth and Trimmings, Yarns and Fibers, Grades 2-6. Curriculum Bulletin No. 8d, 1968-69 Series.

ERIC Educational Resources Information Center

New York City Board of Education, Brooklyn, NY. Bureau of Curriculum Development.

Creating with fabrics, yarns, and fibers--from early basic explorations in handling an assortment of cloths and trimmings, through experiments with stitching and weaving, to the designing and making of bags, hats, and costumes that children can use--is the focus of this curriculum guide. For each grade (2-6), guidelines are provided on (1)…

Assessing Impacts of Navigation Dredging on Atlantic Sturgeon (Acipenser oxyrinchus)

DTIC Science & Technology

2014-11-01

fishes and insect larvae (Smith 1985, Dadswell 2006). Shallow water shoals located adjacent to both sides of the Federal navigation channel, provide a...incision was closed using sterile resorbitive suture material with four to five simple interrupted stitches. An iodine disinfectant was applied to the...1976). Assessment of techniques used to quantify salmon smolt entrainment by a hydraulic suction hopper dredge in the Fraser River estuary. Environment

Temporary clamping of external carotid artery in convexity, parasagittal and temporal base meningioma.

PubMed

Yadav, Yad Ram; Parihar, Vijay; Agarwal, Moneet; Bhatele, Pushp Raj

2012-01-01

The management of intraoperative bleeding during removal of a large hyper vascular meningioma is crucial for safe and efficient surgery. Preoperative embolization of meningioma is the best way to reduce vascularity of meningiomas but this technique is not readily available, costly and has its own limitations. The study is aimed to evaluate the use of temporary clamping of external carotid artery to reduce blood loss and operating time during excision of large convexity, parasagittal or temporal base meningiomas. A prospective study of 115 consecutively operated meningiomas of size 5 cms or more were operated from January 2002 to December2010. Temporary clamping of external carotid artery was done in 61 while 51 cases were managed without clamping. There was significant reduction of blood loss, operative time and blood transfusion given in the temporary clipping group compared to non clipping group. There was stitch abscess in two patients each in clamping, and non clamping group. There was no scalp necrosis or mortality in any of the group. Temporary clamping of external carotid artery is a safe, simple and cost-effective alternative to embolization for the surgery of large meningiomas. This can be practiced at all the centers.

Correlation of Structural Analysis and Test Results for the McDonnell Douglas Stitched/RFI All-Composite Wing Stub Box

NASA Technical Reports Server (NTRS)

Wang, John T.; Jegley, Dawn C.; Bush, Harold G.; Hinrichs, Stephen C.

1996-01-01

The analytical and experimental results of an all-composite wing stub box are presented in this report. The wing stub box, which is representative of an inboard portion of a commercial transport high-aspect-ratio wing, was fabricated from stitched graphite-epoxy material with a Resin Film Infusion manufacturing process. The wing stub box was designed and constructed by the McDonnell Douglas Aerospace Company as part of the NASA Advanced Composites Technology program. The test article contained metallic load-introduction structures on the inboard and outboard ends of the graphite-epoxy wing stub box. The root end of the inboard load introduction structure was attached to a vertical reaction structure, and an upward load was applied to the outermost tip of the outboard load introduction structure to induce bending of the wing stub box. A finite element model was created in which the center portion of the wing-stub-box upper cover panel was modeled with a refined mesh. The refined mesh was required to represent properly the geometrically nonlinear structural behavior of the upper cover panel and to predict accurately the strains in the stringer webs of the stiffened upper cover panel. The analytical and experimental results for deflections and strains are in good agreement.

Mechanical characterization of 2D, 2D stitched, and 3D braided/RTM materials

NASA Technical Reports Server (NTRS)

Deaton, Jerry W.; Kullerd, Susan M.; Portanova, Marc A.

1993-01-01

Braided composite materials have potential for application in aircraft structures. Fuselage frames, floor beams, wing spars, and stiffeners are examples where braided composites could find application if cost effective processing and damage tolerance requirements are met. Another important consideration for braided composites relates to their mechanical properties and how they compare to the properties of composites produced by other textile composite processes being proposed for these applications. Unfortunately, mechanical property data for braided composites do not appear extensively in the literature. Data are presented in this paper on the mechanical characterization of 2D triaxial braid, 2D triaxial braid plus stitching, and 3D (through-the-thickness) braid composite materials. The braided preforms all had the same graphite tow size and the same nominal braid architectures, (+/- 30 deg/0 deg), and were resin transfer molded (RTM) using the same mold for each of two different resin systems. Static data are presented for notched and unnotched tension, notched and unnotched compression, and compression after impact strengths at room temperature. In addition, some static results, after environmental conditioning, are included. Baseline tension and compression fatigue results are also presented, but only for the 3D braided composite material with one of the resin systems.

Automated recognition and tracking of aerosol threat plumes with an IR camera pod

NASA Astrophysics Data System (ADS)

Fauth, Ryan; Powell, Christopher; Gruber, Thomas; Clapp, Dan

2012-06-01

Protection of fixed sites from chemical, biological, or radiological aerosol plume attacks depends on early warning so that there is time to take mitigating actions. Early warning requires continuous, autonomous, and rapid coverage of large surrounding areas; however, this must be done at an affordable cost. Once a potential threat plume is detected though, a different type of sensor (e.g., a more expensive, slower sensor) may be cued for identification purposes, but the problem is to quickly identify all of the potential threats around the fixed site of interest. To address this problem of low cost, persistent, wide area surveillance, an IR camera pod and multi-image stitching and processing algorithms have been developed for automatic recognition and tracking of aerosol plumes. A rugged, modular, static pod design, which accommodates as many as four micro-bolometer IR cameras for 45deg to 180deg of azimuth coverage, is presented. Various OpenCV1 based image-processing algorithms, including stitching of multiple adjacent FOVs, recognition of aerosol plume objects, and the tracking of aerosol plumes, are presented using process block diagrams and sample field test results, including chemical and biological simulant plumes. Methods for dealing with the background removal, brightness equalization between images, and focus quality for optimal plume tracking are also discussed.

Novel laser tissue-soldering technique for dural reconstruction.

PubMed

Gil, Ziv; Shaham, Amit; Vasilyev, Tamar; Brosh, Tamar; Forer, Boaz; Katzir, Abraham; Fliss, Dan M

2005-07-01

The goal of this study was to use a modified version of the CO2 laser-soldering system to develop a simple and reliable technique for the repair of dural defects after excision of brain tumors. The authors used a CO2 fiber optic laser system that they had developed for heating, monitoring, and controlling tissue temperature in situ and in real time, thereby reducing damage to the brain parenchyma. They adapted the system for dural closure by using free fascial grafts in a porcine model. Measures for estimation of reconstruction quality included visual assessment under magnification and direct measurements of adhesive strength and cerebrospinal fluid leak (CSF) pressure. Reliable soldering was achieved in 54 of 57 experiments, providing a 95% success rate. The average peak adhesive strength was 82 +/- 3 mN/cm2. The measured leak pressure of the fascia-dura mater bond was 66 +/- 5 mm Hg. Conventional suturing performed using Prolene stitches resulted in immediate CSF leakage from areas between the stitches and from the area of the needle hole itself. Fascia-dura mater soldering using the CO2 laser is feasible and may support CSF pressure up to six times higher than normal intracranial pressure. Findings of this study may provide a basis for the development of new tools for dural reconstruction.

Using MountainsMap (Digital Surf) surface analysis software as an analysis tool for x-ray mirror optical metrology data

NASA Astrophysics Data System (ADS)

Duffy, Alan; Yates, Brian; Takacs, Peter

2012-09-01

The Optical Metrology Facility at the Canadian Light Source (CLS) has recently purchased MountainsMap surface analysis software from Digital Surf and we report here our experiences with this package and its usefulness as a tool for examining metrology data of synchrotron x-ray mirrors. The package has a number of operators that are useful for determining surface roughness and slope error including compliance with ISO standards (viz. ISO 4287 and ISO 25178). The software is extensible with MATLAB scripts either by loading an m-file or by a user written script. This makes it possible to apply a custom operator to measurement data sets. Using this feature we have applied the simple six-line MATLAB code for the direct least square fitting of ellipses developed by Fitzgibbon et. al. to investigate the residual slope error of elliptical mirrors upon the removal of the best-fit-ellipse. The software includes support for many instruments (e.g. Zygo, MicroMap, etc...) and can import ASCII data (e.g. LTP data). The stitching module allows the user to assemble overlapping images and we report on our experiences with this feature applied to MicroMap surface roughness data. The power spectral density function was determined for the stitched and unstitched data and compared.

Development of a metrological atomic force microscope with a tip-tilting mechanism for 3D nanometrology

NASA Astrophysics Data System (ADS)

Kizu, Ryosuke; Misumi, Ichiko; Hirai, Akiko; Kinoshita, Kazuto; Gonda, Satoshi

2018-07-01

A metrological atomic force microscope with a tip-tilting mechanism (tilting-mAFM) has been developed to expand the capabilities of 3D nanometrology, particularly for high-resolution topography measurements at the surfaces of vertical sidewalls and for traceable measurements of nanodevice linewidth. In the tilting-mAFM, the probe tip is tilted from vertical to 16° at maximum such that the probe tip can touch and trace the vertical sidewall of a nanometer-scale structure; the probe of a conventional atomic force microscope cannot reach the vertical surface because of its finite cone angle. Probe displacement is monitored in three axes by using high-resolution laser interferometry, which is traceable to the SI unit of length. A central-symmetric 3D scanner with a parallel spring structure allows probe scanning with extremely low interaxial crosstalk. A unique technique for scanning vertical sidewalls was also developed and applied. The experimental results indicated high repeatability in the scanned profiles and sidewall angle measurements. Moreover, the 3D measurement of a line pattern was demonstrated, and the data from both sidewalls were successfully stitched together with subnanometer accuracy. Finally, the critical dimension of the line pattern was obtained.