Adaptive Flight Control Research at NASA

NASA Technical Reports Server (NTRS)

Motter, Mark A.

2008-01-01

A broad overview of current adaptive flight control research efforts at NASA is presented, as well as some more detailed discussion of selected specific approaches. The stated objective of the Integrated Resilient Aircraft Control Project, one of NASA s Aviation Safety programs, is to advance the state-of-the-art of adaptive controls as a design option to provide enhanced stability and maneuverability margins for safe landing in the presence of adverse conditions such as actuator or sensor failures. Under this project, a number of adaptive control approaches are being pursued, including neural networks and multiple models. Validation of all the adaptive control approaches will use not only traditional methods such as simulation, wind tunnel testing and manned flight tests, but will be augmented with recently developed capabilities in unmanned flight testing.

NASA/ARC proposed training in intelligent control

NASA Technical Reports Server (NTRS)

Berenji, Hamid R.

1990-01-01

Viewgraphs on NASA Ames Research Center proposed training in intelligent control was presented. Topics covered include: fuzzy logic control; neural networks in control; artificial intelligence in control; hybrid approaches; hands on experience; and fuzzy controllers.

Review of fatigue and fracture research at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Everett, Richard A., Jr.

1988-01-01

Most dynamic components in helicopters are designed with a safe-life constant-amplitude testing approach that has not changed in many years. In contrast, the fatigue methodology in other industries has advanced significantly in the last two decades. Recent research at the NASA Langley Research Center and the U.S. Army Aerostructures Directorate at Langley are reviewed relative to fatigue and fracture design methodology for metallic components. Most of the Langley research was directed towards the damage tolerance design approach, but some work was done that is applicable to the safe-life approach. In the areas of testing, damage tolerance concepts are concentrating on the small-crack effect in crack growth and measurement of crack opening stresses. Tests were conducted to determine the effects of a machining scratch on the fatigue life of a high strength steel. In the area of analysis, work was concentrated on developing a crack closure model that will predict fatigue life under spectrum loading for several different metal alloys including a high strength steel that is often used in the dynamic components of helicopters. Work is also continuing in developing a three-dimensional, finite-element stress analysis for cracked and uncracked isotropic and anisotropic structures. A numerical technique for solving simultaneous equations called the multigrid method is being pursued to enhance the solution schemes in both the finite-element analysis and the boundary element analysis. Finally, a fracture mechanics project involving an elastic-plastic finite element analysis of J-resistance curve is also being pursued.

NASA experiments onboard the controlled impact demonstration

NASA Technical Reports Server (NTRS)

Hayduk, R. J.; Alfaro-Bou, E.; Fasanella, E. L.

1985-01-01

The structural crashworthiness tests conducted by NASA on the December 1, 1984 controlled impact demonstration are discussed. The components and locations of the data acquisition and photographic systems developed by NASA to evaluate impact loads throughout the aircraft structure and the transmission of loads into the dummies are described. The effectiveness of the NASA designed absorbing seats and the vertical, longitudinal, and transverse impact loads are measured. Data that is extremely applicable to crash dynamics structural research was obtained by the data acquisition system and very low load levels were measured for the NASA energy absorbing seats.

Environmental controls on micro fracture processes in shelf ice

NASA Astrophysics Data System (ADS)

Sammonds, Peter

2013-04-01

The recent retreat and collapse of the ice shelves on the Antarctic Peninsula has been associated with regional atmospheric warming, oceanic warming, increased summer melt and shelf flexure. Although the cause of collapse is a matter of active discussion, the process is that of fracture of a creep-brittle material, close to its melting point. The environmental controls on how fracturing initiates, at a micro-scale, strongly determine the macroscopic disintegration of ice shelves. In particular the shelf temperature profile controls the plasticity of the ice shelf; the densification of shelf ice due to melting and re-freezing affects the crack tip stress intensity; the accretion of marine ice at the bottom of the shelf imposes a thermal/mechanical discontinuity; saline environments control crack tip stress corrosion; cyclic loading promotes sub-critical crack propagation. These strong environmental controls on shelf ice fracture means that assessing shelf stability is a non-deterministic problem. How these factors may be parameterized in ice shelf models, through the use of fracture mechanisms maps, is discussed. The findings are discussed in relation to the stability of Larsen C.

Circulation Control in NASA's Vehicle Systems

NASA Technical Reports Server (NTRS)

Rich, Paul; McKinley, Bob; Jones, Greg

2005-01-01

Specific to the application of any technology to a vehicle, such as circulation control, it is important to understand the process that NASA is using to set its direction in research and development. To see how circulation control fits into any given NASA program requires the reader to understand NASA's Vehicle Systems (VS) Program. The VS Program recently celebrated its first year of existence with an annual review - an opportunity to look back on accomplishments, solicit feedback, expand national advocacy and support for the program, and recognize key contributions. Since its formation last year, Vehicle Systems has coordinated seven existing entities in a streamlined aeronautics research effort. It invests in vehicle technologies to protect the environment, make air travel more accessible and affordable for Americans, enable exploration through new aerospace missions, and augment national security. This past year has seen a series of valuable partnerships with industry, academia, and government agencies to make crucial aeronautics advances and assure America s future in flight.

Discolored Fracture Zones in Martian Sandstone

NASA Image and Video Library

2015-12-17

This view from NASA's Curiosity Mars rover shows an example of discoloration closely linked to fractures in the Stimson formation sandstone on lower Mount Sharp. The pattern is evident along two perpendicular fractures. Curiosity's Navigation Camera (Navcam) acquired the component images of this mosaic on Aug. 23, 2015, during the 1.083rd Martian day, or sol, of the mission. The location is along the rover's path between "Marias Pass" and "Bridger Basin." In this region, the rover has found fracture zones to be associated with rock compositions enriched in silica, relative to surrounding bedrock. http://photojournal.jpl.nasa.gov/catalog/PIA20268

Controls on fracture distribution in the Giddings Austin Chalk

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

Wagner, D.T.

1990-09-01

Fracture distribution in the Giddings Austin Chalk is controlled by both structure and the stratigraphy of the Austin Group. Parameters that most affect reservoir performance include fracture width, height, and spacing, as well as the number of fracture sets and their orientations. Lateral variance of these parameters is a function of structural position, while vertical change is related to stratigraphy. The Austin Chalk productive trend is thought to coincide with the hingeline of the Gulf Coast basin, where extension has been concentrated during subsidence of the basin. Fracturing is attributed to a number of mechanisms including normal faulting, bending overmore » buried structures, gravity creep, differential compaction, and aquathermal pressuring. A change in structural style from faulting to flexure takes place from west to east across the Giddings field, accompanied by a change in fracture distribution. In the west, fractures develop only in close proximity to faults whereas in the east they are more widely distributed over broad warps. Stratigraphic controls include lithology, porosity, bed thickness, and ductility contrast between adjacent beds. The Austin Chalk consists of sparse biomicrite interbedded with marls, shales, and clay seams. In general, thin beds are more highly fractured than thick beds, and clean limestone is more highly fractured than marl or shale. Where the more ductile marls and clays exceed a critical thickness, fractures tend to terminate within individual chalk beds, resulting in barriers to vertical flow within the reservoir.« less

NASA Thermal Control Technologies for Robotic Spacecraft

NASA Technical Reports Server (NTRS)

Swanson, Theodore D.; Birur, Gajanana C.

2003-01-01

Technology development is inevitably a dynamic process in search of an elusive goal. It is never truly clear whether the need for a particular technology drives its development, or the existence of a new capability initiates new applications. Technology development for the thermal control of spacecraft presents an excellent example of this situation. Nevertheless, it is imperative to have a basic plan to help guide and focus such an effort. Although this plan will be a living document that changes with time to reflect technological developments, perceived needs, perceived opportunities, and the ever-changing funding environment, it is still a very useful tool. This presentation summarizes the current efforts at NASA/Goddard and NASA/JPL to develop new thermal control technology for future robotic NASA missions.

NASA/DOD Control/Structures Interaction Technology, 1986

NASA Technical Reports Server (NTRS)

Wright, Robert L. (Compiler)

1987-01-01

Papers presented at the CSI Technology Conference are given. The conference was jointly sponsored by the NASA Office of Aeronautics and Space Technology and the Department of Defense. The conference is the beginning of a series of annual conferences whose purpose is to report to industry, academia, and government agencies the current status of Control/Structures Interaction technology. The conference program was divided into five sessions: (1) Future spacecraft requirements; Technology issues and impact; (2) DOD special topics; (3) Large space systems technology; (4) Control of flexible structures, and (5) Selected NASA research in control structures interaction.

Material Characterization for Ductile Fracture Prediction

NASA Technical Reports Server (NTRS)

Hill, Michael R.

2000-01-01

The research summarized in this document provides valuable information for structural health evaluation of NASA infrastructure. Specifically, material properties are reported which will enable calibration of ductile fracture prediction methods for three high-toughness metallic materials and one aluminum alloy which can be found in various NASA facilities. The task of investigating these materials has also served to validate an overall methodology for ductile fracture prediction is currently being employed at NASA. In facilitating the ability to incorporate various materials into the prediction scheme, we have provided data to enable demonstration of the overall generality of the approach.

Spacecraft Hybrid (Mixed-Actuator) Attitude Control Experiences on NASA Science Missions

NASA Technical Reports Server (NTRS)

Dennehy, Cornelius J.

2014-01-01

There is a heightened interest within NASA for the design, development, and flight implementation of mixed-actuator hybrid attitude control systems for science spacecraft that have less than three functional reaction wheel actuators. This interest is driven by a number of recent reaction wheel failures on aging, but what could be still scientifically productive, NASA spacecraft if a successful hybrid attitude control mode can be implemented. Over the years, hybrid (mixed-actuator) control has been employed for contingency attitude control purposes on several NASA science mission spacecraft. This paper provides a historical perspective of NASA's previous engineering work on spacecraft mixed-actuator hybrid control approaches. An update of the current situation will also be provided emphasizing why NASA is now so interested in hybrid control. The results of the NASA Spacecraft Hybrid Attitude Control Workshop, held in April of 2013, will be highlighted. In particular, the lessons learned captured from that workshop will be shared in this paper. An update on the most recent experiences with hybrid control on the Kepler spacecraft will also be provided. This paper will close with some future considerations for hybrid spacecraft control.

Effects of simplifying fracture network representation on inert chemical migration in fracture-controlled aquifers

USGS Publications Warehouse

Wellman, Tristan; Shapiro, Allen M.; Hill, Mary C.

2009-01-01

While it is widely recognized that highly permeable 'large-scale' fractures dominate chemical migration in many fractured aquifers, recent studies suggest that the pervasive 'small-scale' fracturing once considered of less significance can be equally important for characterizing the spatial extent and residence time associated with transport processes. A detailed examination of chemical migration through fracture-controlled aquifers is used to advance this conceptual understanding. The influence of fracture structure is evaluated by quantifying the effects to transport caused by a systematic removal of fractures from three-dimensional discrete fracture models whose attributes are derived from geologic and hydrologic conditions at multiple field sites. Results indicate that the effects to transport caused by network simplification are sensitive to the fracture network characteristics, degree of network simplification, and plume travel distance, but primarily in an indirect sense since correlation to individual attributes is limited. Transport processes can be 'enhanced' or 'restricted' from network simplification meaning that the elimination of fractures may increase or decrease mass migration, mean travel time, dispersion, and tailing of the concentration plume. The results demonstrate why, for instance, chemical migration may not follow the classic advection-dispersion equation where dispersion approximates the effect of the ignored geologic structure as a strictly additive process to the mean flow. The analyses further reveal that the prediction error caused by fracture network simplification is reduced by at least 50% using the median estimate from an ensemble of simplified fracture network models, and that the error from network simplification is at least 70% less than the stochastic variability from multiple realizations. Copyright 2009 by the American Geophysical Union.

Air Breathing Propulsion Controls and Diagnostics Research at NASA Glenn Under NASA Aeronautics Research Mission Programs

NASA Technical Reports Server (NTRS)

Garg, Sanjay

2014-01-01

The Intelligent Control and Autonomy Branch (ICA) at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with other organizations within GRC and across NASA, the U.S. aerospace industry, and academia to develop advanced controls and health management technologies that will help meet the goals of the NASA Aeronautics Research Mission Directorate (ARMD) Programs. These efforts are primarily under the various projects under the Fundamental Aeronautics Program (FAP) and the Aviation Safety Program (ASP). The ICA Branch is focused on advancing the state-of-the-art of aero-engine control and diagnostics technologies to help improve aviation safety, increase efficiency, and enable operation with reduced emissions. This paper describes the various ICA research efforts under the NASA Aeronautics Research Mission Programs with a summary of motivation, background, technical approach, and recent accomplishments for each of the research tasks.

Air Breathing Propulsion Controls and Diagnostics Research at NASA Glenn Under NASA Aeronautics Research Mission Programs

NASA Technical Reports Server (NTRS)

Garg, Sanjay

2015-01-01

The Intelligent Control and Autonomy Branch (ICA) at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with other organizations within GRC and across NASA, the U.S. aerospace industry, and academia to develop advanced controls and health management technologies that will help meet the goals of the NASA Aeronautics Research Mission Directorate (ARMD) Programs. These efforts are primarily under the various projects under the Advanced Air Vehicles Program (AAVP), Airspace Operations and Safety Program (AOSP) and Transformative Aeronautics Concepts Program (TAC). The ICA Branch is focused on advancing the state-of-the-art of aero-engine control and diagnostics technologies to help improve aviation safety, increase efficiency, and enable operation with reduced emissions. This paper describes the various ICA research efforts under the NASA Aeronautics Research Mission Programs with a summary of motivation, background, technical approach, and recent accomplishments for each of the research tasks.

Snapshot of Active Flow Control Research at NASA Langley

NASA Technical Reports Server (NTRS)

Washburn, A. E.; Gorton, S. Althoff; Anders, S. G.

2002-01-01

NASA Langley is aggressively investigating the potential advantages of active flow control as opposed to more traditional aerodynamic techniques. Many of these techniques will be blended with advanced materials and structures to further enhance payoff. Therefore a multi-disciplinary approach to technology development is being attempted that includes researchers from the more historical disciplines of fluid mechanics. acoustics, material science, structural mechanics, and control theory. The overall goals of the topics presented are focused on advancing the state of knowledge and understanding of controllable fundamental mechanisms in fluids rather than on specific engineering problems. An organizational view of current research activities at NASA Langley in active flow control as supported by several programs such as the Morphing Project under Breakthrough Vehicle Technologies Program (BVT). the Ultra-Efficient Engine Technology Program (UEET), and the 21st Century Aircraft Technology Program (TCAT) is presented. On-center research as well as NASA Langley funded contracts and grants are discussed at a relatively high level. The products of this research, as part of the fundamental NASA R and D (research and development) program. will be demonstrated as either bench-top experiments, wind-tunnel investigations, or in flight tests. Later they will be transferred to more applied research programs within NASA, DOD (Department of Defense), and U.S. industry.

Miranda Fractures, Grooves and Craters

NASA Image and Video Library

1996-01-29

This image of the Uranian moon, Miranda, was taken Jan 24, 1986 by NASA's Voyager 2. This image reveals a bewildering variety of fractures, grooves and craters, as well as features of different albedos reflectancea. http://photojournal.jpl.nasa.gov/catalog/PIA00140

Prevalence of overweight in children with bone fractures: a case control study.

PubMed

Valerio, Giuliana; Gallè, Francesca; Mancusi, Caterina; Di Onofrio, Valeria; Guida, Pasquale; Tramontano, Antonino; Ruotolo, Edoardo; Liguori, Giorgio

2012-10-22

Children's fractures have been enlisted among orthopaedics complaints of childhood obesity. Unhealthy lifestyle behaviours may contribute to increased risk. This study described the prevalence of overweight/obesity in children and adolescents reporting a recent fracture in relation to gender, dynamic of trauma, and site of fracture. Four-hundred-forty-nine children and adolescents with fracture and 130 fracture-free controls were recruited from a large children's hospital. The interaction between overweight and gender, dynamic of trauma, site of fracture was explored. Sports participation, television viewing, and calcium intake were also investigated. Overweight/obesity rate was increased in girls with fracture either at the upper or the lower limb (p= 0.004), while it was increased only in boys with fracture at the lower limb (p <0.02). Overweight/obesity rate did not differ between groups with low or moderate trauma. TV viewing ≥ 2 hrs was more frequent in children with fractures than controls (61.5% vs 34.5%, p =0.015) in the overweight/obese group. The increased prevalence of overweight/obesity in children with fractures is related to gender and site of fracture. Higher levels of sedentary behaviours characterize overweight children reporting fractures.

NASA Project Planning and Control Handbook

NASA Technical Reports Server (NTRS)

Moreland, Robert; Claunch, Cathy L.

2016-01-01

This handbook provides an overview of the fundamental principles and explains the functions and products that go into project planning and control. The 2010 Interim Results of the NASA Program Planning and Control (PPC) Study identified seven categories of activities for PPC, and those provide the basis for the seven functions described in this handbook. This handbook maps out the interfaces and interactions between PPC functions, as well as their external interfaces. This integration of information and products within and between functions is necessary to form the whole picture of how a project is progressing. The handbook descriptions are meant to facilitate consistent, common, and comprehensive approaches for providing valued analysis, assessment, and evaluation focused on the project level at NASA. The handbook also describes activities in terms of function rather than the job title or the specific person or organization responsible for the activity, which could differ by Center or size of a project. This handbook is primarily guidance for project planning and control: however, the same principles apply to programs and generally apply to institutional planning and control.

Prevalence of overweight in children with bone fractures: a case control study

PubMed Central

2012-01-01

Background Children's fractures have been enlisted among orthopaedics complaints of childhood obesity. Unhealthy lifestyle behaviours may contribute to increased risk. This study described the prevalence of overweight/obesity in children and adolescents reporting a recent fracture in relation to gender, dynamic of trauma, and site of fracture. Methods Four-hundred-forty-nine children and adolescents with fracture and 130 fracture-free controls were recruited from a large children’s hospital. The interaction between overweight and gender, dynamic of trauma, site of fracture was explored. Sports participation, television viewing, and calcium intake were also investigated. Results Overweight/obesity rate was increased in girls with fracture either at the upper or the lower limb (p= 0.004), while it was increased only in boys with fracture at the lower limb (p <0.02). Overweight/obesity rate did not differ between groups with low or moderate trauma. TV viewing ≥ 2 hrs was more frequent in children with fractures than controls (61.5% vs 34.5%, p =0.015) in the overweight/obese group. Conclusions The increased prevalence of overweight/obesity in children with fractures is related to gender and site of fracture. Higher levels of sedentary behaviours characterize overweight children reporting fractures. PMID:23088687

Guidance, Navigation and Control Innovations at the NASA Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Ericsson, Aprille Joy

2002-01-01

A viewgraph presentation on guidance navigation and control innovations at the NASA Goddard Space Flight Center is presented. The topics include: 1) NASA's vision; 2) NASA's Mission; 3) Earth Science Enterprise (ESE); 4) Guidance, Navigation and Control Division (GN&C); 5) Landsat-7 Earth Observer-1 Co-observing Program; and 6) NASA ESE Vision.

Fractured Craters on Ganymede

NASA Technical Reports Server (NTRS)

1997-01-01

Two highly fractured craters are visible in this high resolution image of Jupiter's moon, Ganymede. NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. North is to the top of the picture and the sun illuminates the surface from the southeast. The two craters in the center of the image lie in the ancient dark terrain of Marius Regio, at 40 degrees latitude and 201 degrees longitude, at the border of a region of bright grooved terrain known as Byblus Sulcus (the eastern portion of which is visible on the left of this image). Pervasive fracturing has occurred in this area that has completely disrupted these craters and destroyed their southern and western walls. Such intense fracturing has occurred over much of Ganymede's surface and has commonly destroyed older features. The image covers an area approximately 26 kilometers (16 miles) by 18 kilometers (11 miles) across at a resolution of 86 meters (287 feet) per picture element. The image was taken on September 6, 1996 by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

Sixth NASA Glenn Research Center Propulsion Control and Diagnostics (PCD) Workshop

NASA Technical Reports Server (NTRS)

Litt, Jonathan S. (Compiler)

2018-01-01

The Intelligent Control and Autonomy Branch at NASA Glenn Research Center hosted the Sixth Propulsion Control and Diagnostics Workshop on August 22-24, 2017. The objectives of this workshop were to disseminate information about research being performed in support of NASA Aeronautics programs; get feedback from peers on the research; and identify opportunities for collaboration. There were presentations and posters by NASA researchers, Department of Defense representatives, and engine manufacturers on aspects of turbine engine modeling, control, and diagnostics.

NASA/FLAGRO - FATIGUE CRACK GROWTH COMPUTER PROGRAM

NASA Technical Reports Server (NTRS)

Forman, R. G.

1994-01-01

Structural flaws and cracks may grow under fatigue inducing loads and, upon reaching a critical size, cause structural failure to occur. The growth of these flaws and cracks may occur at load levels well below the ultimate load bearing capability of the structure. The Fatigue Crack Growth Computer Program, NASA/FLAGRO, was developed as an aid in predicting the growth of pre-existing flaws and cracks in structural components of space systems. The earlier version of the program, FLAGRO4, was the primary analysis tool used by Rockwell International and the Shuttle subcontractors for fracture control analysis on the Space Shuttle. NASA/FLAGRO is an enhanced version of the program and incorporates state-of-the-art improvements in both fracture mechanics and computer technology. NASA/FLAGRO provides the fracture mechanics analyst with a computerized method of evaluating the "safe crack growth life" capabilities of structural components. NASA/FLAGRO could also be used to evaluate the damage tolerance aspects of a given structural design. The propagation of an existing crack is governed by the stress field in the vicinity of the crack tip. The stress intensity factor is defined in terms of the relationship between the stress field magnitude and the crack size. The propagation of the crack becomes catastrophic when the local stress intensity factor reaches the fracture toughness of the material. NASA/FLAGRO predicts crack growth using a two-dimensional model which predicts growth independently in two directions based on the calculation of stress intensity factors. The analyst can choose to use either a crack growth rate equation or a nonlinear interpolation routine based on tabular data. The growth rate equation is a modified Forman equation which can be converted to a Paris or Walker equation by substituting different values into the exponent. This equation provides accuracy and versatility and can be fit to data using standard least squares methods. Stress

Damage control and intramedullary nailing for long bone fractures in polytrauma patients.

PubMed

Patka, Peter

2017-06-01

The early fracture treatment in patients with multiple injuries should be focused on damage control. The fracture type and its location, local soft tissue condition as well as the patient's physiological condition shall determine the time and type of fracture treatment. Prevention of local and systemic complications must be immediately considered and included in the treatment planning. The use of external fixator (ExFix), which will be replaced by IM-implants in most cases at a later stage, provides adequate temporary fracture stabilization with less collateral damage. Good clinical results can be expected in patients with long bone fractures if the principles of damage control surgery are applied and local complications are prevented through proper reduction, firm fixation, early soft tissue reconstruction, and early rehabilitation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Vitamin D and Fracture Risk in Early Childhood: A Case-Control Study

PubMed Central

Anderson, Laura N.; Heong, Sze Wing; Chen, Yang; Thorpe, Kevin E.; Adeli, Khosrow; Howard, Andrew; Sochett, Etienne; Birken, Catherine S.; Parkin, Patricia C.; Maguire, Jonathon L.; Abdullah, Kawsari; Anderson, Laura N.; Birken, Catherine S.; Borkhoff, Cornelia M.; Carsley, Sarah; Chen, Yang; Katz-Lavigne, Mikael; Kavikondala, Kanthi; Kowal, Christine; Maguire, Jonathon L.; Mason, Dalah; Omand, Jessica; Parkin, Patricia C.; Persaud, Navindra; van den Heuvel, Meta; Baker, Jillian; Barozzino, Tony; Bonifacio, Joey; Campbell, Douglas; Cheema, Sohail; Chisamore, Brian; Danayan, Karoon; Das, Paul; Derocher, Mary Beth; Do, Anh; Dorey, Michael; Freeman, Sloane; Fung, Keewai; Guiang, Charlie; Handford, Curtis; Hatch, Hailey; Jacobson, Sheila; Kiran, Tara; Knowles, Holly; Kwok, Bruce; Lakhoo, Sheila; Lam-Antoniades, Margarita; Lau, Eddy; Leung, Fok-Han; Loo, Jennifer; Mahmoud, Sarah; Moodie, Rosemary; Morinis, Julia; Naymark, Sharon; Neelands, Patricia; Owen, James; Peer, Michael; Perlmutar, Marty; Persaud, Navindra; Pinto, Andrew; Porepa, Michelle; Ramji, Nasreen; Ramji, Noor; Rosenthal, Alana; Saunderson, Janet; Saxena, Rahul; Sgro, Michael; Shepherd, Susan; Smiltnieks, Barbara; Taylor, Carolyn; Weisdors, Thea; Wijayasinghe, Sheila; Wong, Peter; Ying, Ethel; Young, Elizabeth

2017-01-01

Abstract The objective of this study was to evaluate the association of vitamin D intake and serum levels with fracture risk in children under 6 years of age. A case-control study was conducted in Toronto, Ontario, Canada. Cases were recruited from the fracture clinic at the Hospital for Sick Children, and matched controls were obtained from the TARGet Kids! primary-care research network. Controls were matched to cases on age, sex, height, and season. Fracture risk was estimated from conditional logistic regression, with adjustment for skin type, fracture history, waist circumference, outdoor free play, neighborhood income, soda consumption, and child's birth weight. A total of 206 cases were recruited during May 2009–April 2013 and matched to 343 controls. Serum 25-hydroxyvitamin D concentration (per 10-nmol/L increment: adjusted odds ratio (aOR) = 0.95, 95% confidence interval (CI): 0.88, 1.03) and intake of cow's milk (<2 cups/day vs. 2 cups/day: aOR = 0.95 (95% CI: 0.60, 1.52); >2 cups/day vs. 2 cups/day: aOR = 1.39 (95% CI: 0.85, 2.23)) were not significantly associated with reduced odds of fracture. A statistically significant association was observed between child use of vitamin D supplements and decreased odds of fracture (yes vs. no: aOR = 0.42, 95% CI: 0.25, 0.69). Vitamin D supplementation, but not serum 25-hydroxyvitamin D level or milk intake, was associated with reduced fracture risk among these healthy young children. PMID:28459987

[Effects of Surgically Treated Pelvic Ring and Acetabular Fractures on Postural Control].

PubMed

Lang, P; Schnegelberger, A; Riesner, H-J; Stuby, F; Friemert, B; Palm, H-G

2016-04-01

The aim of surgical treatment of pelvic ring and acetabular fractures is to allow rapid mobilisation of patients in order to restore stance and gait stability (postural control), as this significantly correlates with a positive outcome. The regulation of postural stability is mainly controlled by transmission of proprioceptive stimuli. In addition, the pelvis serves as a connection between the legs and the spine and thus is also of great importance for mechanical stabilisation. It remains unclear whether surgical treatment of pelvic ring and acetabular fractures affects the regulation of postural control. Therefore, the aim of this study was to examine the impact of surgically treated pelvic ring and acetabular fractures on postural stability by means of computerised dynamic posturography (CDP) after a mean of 35 months and to compare the results with a healthy control group. A retrospective case control study of 38 patients with surgically treated pelvic ring and acetabular fractures and 38 healthy volunteers was carried out using CDP. The average time of follow-up was 35 (12-78) months. The most important outcome parameter in this investigation was the overall stability index (OSI). Hip joint mobility, the health-related quality of life (SF-12) and pain were supplementary outcome parameters. It was found that surgically treated pelvic ring and acetabular fractures had no influence on postural stability. The OSI was 2.1 ° in the patient group and 1.9 ° in the control group. There was no significant difference between the groups in hip joint mobility. A total of 52 % of patients showed no or only mild pain. Mean health-related quality of life was the same as in the total population. Surgically treated pelvic ring and acetabular fractures do not lead to deterioration in postural control in the mid term. This is of high prognostic importance for rapid mobilisation of the patients. Therefore no increase in the risk of falling is expected after successfully

NASA Workshop on Hybrid (Mixed-Actuator) Spacecraft Attitude Control

NASA Technical Reports Server (NTRS)

Dennehy, Cornelius J.; Kunz, Nans

2014-01-01

At the request of the Science Mission Directorate Chief Engineer, the NASA Technical Fellow for Guidance, Navigation & Control assembled and facilitated a workshop on Spacecraft Hybrid Attitude Control. This multi-Center, academic, and industry workshop, sponsored by the NASA Engineering and Safety Center (NESC), was held in April 2013 to unite nationwide experts to present and discuss the various innovative solutions, techniques, and lessons learned regarding the development and implementation of the various hybrid attitude control system solutions investigated or implemented. This report attempts to document these key lessons learned with the 16 findings and 9 NESC recommendations.

Overview of Active Flow Control at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Pack, L. G.; Joslin, R. D.

1998-01-01

The paper summarizes Active Flow Control projects currently underway at the NASA Langley Research Center. Technology development is being pursued within a multidisciplinary, cooperative approach, involving the classical disciplines of fluid mechanics, structural mechanics, material science, acoustics, and stability and control theory. Complementing the companion papers in this session, the present paper will focus on projects that have the goal of extending the state-of-the-art in the measurement, prediction, and control of unsteady, nonlinear aerodynamics. Toward this goal, innovative actuators, micro and macro sensors, and control strategies are considered for high payoff flow control applications. The target payoffs are outlined within each section below. Validation of the approaches range from bench-top experiments to wind-tunnel experiments to flight tests. Obtaining correlations for future actuator and sensor designs are implicit in the discussion. The products of the demonstration projects and design tool development from the fundamental NASA R&D level technology will then be transferred to the Applied Research components within NASA, DOD, and US Industry. Keywords: active flow control, separation control, MEMS, review

Propulsion Controls and Diagnostics Research at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Garg, Sanjay

2007-01-01

With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. Also the propulsion systems required to enable the National Aeronautics and Space Administration (NASA) Vision for Space Exploration in an affordable manner will need to have high reliability, safety and autonomous operation capability. The Controls and Dynamics Branch (CDB) at NASA Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with other organizations within GRC and across NASA, the U.S. aerospace industry, and academia to develop advanced controls and health management technologies that will help meet these challenges through the concept of Intelligent Propulsion Systems. This paper describes the current activities of the CDB under the NASA Aeronautics Research and Exploration Systems Missions. The programmatic structure of the CDB activities is described along with a brief overview of each of the CDB tasks including research objectives, technical challenges, and recent accomplishments. These tasks include active control of propulsion system components, intelligent propulsion diagnostics and control for reliable fault identification and accommodation, distributed engine control, and investigations into unsteady propulsion systems.

Application of characteristic time concepts for hydraulic fracture configuration design, control, and optimization

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

Advani, S.H.; Lee, T.S.; Moon, H.

1992-10-01

The analysis of pertinent energy components or affiliated characteristic times for hydraulic stimulation processes serves as an effective tool for fracture configuration designs optimization, and control. This evaluation, in conjunction with parametric sensitivity studies, provides a rational base for quantifying dominant process mechanisms and the roles of specified reservoir properties relative to controllable hydraulic fracture variables for a wide spectrum of treatment scenarios. Results are detailed for the following multi-task effort: (a) Application of characteristic time concept and parametric sensitivity studies for specialized fracture geometries (rectangular, penny-shaped, elliptical) and three-layered elliptic crack models (in situ stress, elastic moduli, and fracturemore » toughness contrasts). (b) Incorporation of leak-off effects for models investigated in (a). (c) Simulation of generalized hydraulic fracture models and investigation of the role of controllable vaxiables and uncontrollable system properties. (d) Development of guidelines for hydraulic fracture design and optimization.« less

NASA Armstrong Flight Research Center Dynamics and Controls Branch

NASA Technical Reports Server (NTRS)

Jacobson, Steve

2015-01-01

NASA Armstrong continues its legacy of exciting work in the area of Dynamics and Control of advanced vehicle concepts. This presentation describes Armstrongs research in control of flexible structures, peak seeking control and adaptive control in the Spring of 2015.

Structural-Diagenetic Controls on Fracture Opening in Tight Gas Sandstone Reservoirs, Alberta Foothills

NASA Astrophysics Data System (ADS)

Ukar, Estibalitz; Eichhubl, Peter; Fall, Andras; Hooker, John

2013-04-01

progressively decreases from the faulted cores of mesoscopic folds to their forelimbs, with lowest intensities within relatively undeformed backlimb strata. Fracture apertures locally increase adjacent to reverse faults without an overall increase in fracture frequency. Fluid inclusion analyses of crack-seal quartz cement indicate both aqueous and methane-rich inclusions are present. Homogenization temperatures of two-phase inclusions indicate synkinematic fracture cement precipitation and fracture opening under conditions at or near maximum burial of 190-210°C in core samples, and 120-160°C in outcrop samples. In comparison with the fracture evolution in other, less deformed tight-gas sandstone reservoirs such as the Piceance and East Texas basins where fracture opening is primarily controlled by gas generation, gas charge, and pore fluid pressure, these results suggest a strong control of regional tectonic processes on fracture generation. In conjunction with timing and rate of gas charge, rates of fracture cement growth, and stratigraphic-lithological controls, these processes determine the overall distribution of open fractures in these reservoirs.

Structural-Diagenetic Controls on Fracture Opening in Tight Gas Sandstone Reservoirs, Alberta Foothills

NASA Astrophysics Data System (ADS)

Ukar, E.; Eichhubl, P.; Fall, A.; Hooker, J. N.

2012-12-01

progressively decreases from the faulted cores of mesoscopic folds to their forelimbs, with lowest intensities within relatively undeformed backlimb strata. Fracture apertures locally increase adjacent to reverse faults without an overall increase in fracture frequency. Fluid inclusion analyses of crack-seal quartz cement indicate both aqueous and methane-rich inclusions are present. Homogenization temperatures of two-phase inclusions indicate synkinematic fracture cement precipitation and fracture opening under conditions at or near maximum burial of 190-210°C in core samples, and 120-160°C in outcrop samples. In comparison with the fracture evolution in other, less deformed tight-gas sandstone reservoirs such as the Piceance and East Texas basins where fracture opening is primarily controlled by gas generation, gas charge, and pore fluid pressure, these results suggest a strong control of regional tectonic processes on fracture generation. In conjunction with timing and rate of gas charge, rates of fracture cement growth, and stratigraphic-lithological controls, these processes determine the overall distribution of open fractures in these reservoirs.

Structural controls on anomalous transport in fractured porous rock

NASA Astrophysics Data System (ADS)

Edery, Yaniv; Geiger, Sebastian; Berkowitz, Brian

2016-07-01

Anomalous transport is ubiquitous in a wide range of disordered systems, notably in fractured porous formations. We quantitatively identify the structural controls on anomalous tracer transport in a model of a real fractured geological formation that was mapped in an outcrop. The transport, determined by a continuum scale mathematical model, is characterized by breakthrough curves (BTCs) that document anomalous (or "non-Fickian") transport, which is accounted for by a power law distribution of local transition times ψ>(t>) within the framework of a continuous time random walk (CTRW). We show that the determination of ψ>(t>) is related to fractures aligned approximately with the macroscopic direction of flow. We establish the dominant role of fracture alignment and assess the statistics of these fractures by determining a concentration-visitation weighted residence time histogram. We then convert the histogram to a probability density function (pdf) that coincides with the CTRW ψ>(t>) and hence anomalous transport. We show that the permeability of the geological formation hosting the fracture network has a limited effect on the anomalous nature of the transport; rather, it is the fractures transverse to the flow direction that play the major role in forming the long BTC tail associated with anomalous transport. This is a remarkable result, given the complexity of the flow field statistics as captured by concentration transitions.

Monitoring Hydraulic Fracturing Using Ground-Based Controlled Source Electromagnetics

NASA Astrophysics Data System (ADS)

Hickey, M. S.; Trevino, S., III; Everett, M. E.

2017-12-01

Hydraulic fracturing allows hydrocarbon production in low permeability formations. Imaging the distribution of fluid used to create a hydraulic fracture can aid in the characterization of fracture properties such as extent of plume penetration as well as fracture azimuth and symmetry. This could contribute to improving the efficiency of an operation, for example, in helping to determine ideal well spacing or the need to refracture a zone. A ground-based controlled-source electromagnetics (CSEM) technique is ideal for imaging the fluid due to the change in field caused by the difference in the conductive properties of the fluid when compared to the background. With advances in high signal to noise recording equipment, coupled with a high-power, broadband transmitter we can show hydraulic fracture extent and azimuth with minimal processing. A 3D finite element code is used to model the complete well casing along with the layered subsurface. This forward model is used to optimize the survey design and isolate the band of frequencies with the best response. In the field, the results of the modeling are also used to create a custom pseudorandom numeric (PRN) code to control the frequencies transmitted through a grounded dipole source. The receivers record the surface voltage across two grounded dipoles, one parallel and one perpendicular to the transmitter. The data are presented as the displays of amplitude ratios across several frequencies with the associated spatial information. In this presentation, we show multiple field results in multiple basins in the United States along with the CSEM theory used to create the survey designs.

Minimizing damage to a propped fracture by controlled flowback procedures

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

Robinson, B.M.; Holditch, S.A.; Whitehead, W.S.

1988-06-01

Severe fracture-conductivity damage can result from proppant crushing and/or proppant flowback into the wellbore. Such damage is often concentrated near the wellbore and can directly affect postfracture performance. Most of the time severe fracture-conductivity damage can be minimized by choosing the correct type of proppant for a particular well. In many cases, however, this is not enough. To minimize excessive crushing or to prevent proppant flowback, it is also necessary to control carefully the flowback of the well after the treatment. Specific procedures can be followed to minimize severe fracture-conductivity damage. These procedures involve controlling the rates at which loadmore » fluids are recovered and maximizing backpressure against the formation. These procedures require much more time and effort than is normally spent on postfracture cleanup; however, the efforts could result in better performance.« less

The Fifth NASA/DOD Controls-Structures Interaction Technology Conference, part 2

NASA Technical Reports Server (NTRS)

Newsom, Jerry R. (Compiler)

1993-01-01

This publication is a compilation of the papers presented at the Fifth NASA/DoD Controls-Structures Interaction (CSI) Technology Conference held in Lake Tahoe, Nevada, March 3-5, 1992. The conference, which was jointly sponsored by the NASA Office of Aeronautics and Space Technology and the Department of Defense, was organized by the NASA Langley Research Center. The purpose of this conference was to report to industry, academia, and government agencies on the current status of controls-structures interaction technology. The agenda covered ground testing, integrated design, analysis, flight experiments and concepts.

The Fifth NASA/DOD Controls-Structures Interaction Technology Conference, part 1

NASA Technical Reports Server (NTRS)

Newsom, Jerry R. (Compiler)

1993-01-01

This publication is a compilation of the papers presented at the Fifth NASA/DoD Controls-Structures Interaction (CSI) Technology Conference held in Lake Tahoe, Nevada, March 3-5, 1992. The conference, which was jointly sponsored by the NASA Office of Aeronautics and Space Technology and the Department of Defense, was organized by the NASA Langley Research Center. The purpose of this conference was to report to industry, academia, and government agencies on the current status of controls-structures interaction technology. The agenda covered ground testing, integrated design, analysis, flight experiments and concepts.

Flight Control Laws for NASA's Hyper-X Research Vehicle

NASA Technical Reports Server (NTRS)

Davidson, J.; Lallman, F.; McMinn, J. D.; Martin, J.; Pahle, J.; Stephenson, M.; Selmon, J.; Bose, D.

1999-01-01

The goal of the Hyper-X program is to demonstrate and validate technology for design and performance predictions of hypersonic aircraft with an airframe-integrated supersonic-combustion ramjet propulsion system. Accomplishing this goal requires flight demonstration of a hydrogen-fueled scramjet powered hypersonic aircraft. A key enabling technology for this flight demonstration is flight controls. Closed-loop flight control is required to enable a successful stage separation, to achieve and maintain the design condition during the engine test, and to provide a controlled descent. Before the contract award, NASA developed preliminary flight control laws for the Hyper-X to evaluate the feasibility of the proposed scramjet test sequence and descent trajectory. After the contract award, a Boeing/NASA partnership worked to develop the current control laws. This paper presents a description of the Hyper-X Research Vehicle control law architectures with performance and robustness analyses. Assessments of simulated flight trajectories and stability margin analyses demonstrate that these control laws meet the flight test requirements.

Updated Fatigue-Crack-Growth And Fracture-Mechanics Software

NASA Technical Reports Server (NTRS)

Forman, Royce G.; Shivakumar, Venkataraman; Newman, James C., Jr.

1995-01-01

NASA/FLAGRO 2.0 developed as analytical aid in predicting growth and stability of preexisting flaws and cracks in structural components of aerospace systems. Used for fracture-control analysis of space hardware. Organized into three modules to maximize efficiency in operation. Useful in: (1) crack-instability/crack-growth analysis, (2) processing raw crack-growth data from laboratory tests, and (3) boundary-element analysis to determine stresses and stress-intensity factors. Written in FORTRAN 77 and ANSI C.

Fracture criteria for discontinuously reinforced metal matrix composites

NASA Technical Reports Server (NTRS)

Rack, H. J.; Goree, J. G.; Albritton, J.; Ratnaparkhi, P.

1988-01-01

Summarized is the progress achieved during the period September 16, 1987 to August 15, l988 on NASA Grant NAG1-724, Fracture Criteria for Discontinuously Reinforced Metal Matrix Composites. Appended are copies of three manuscripts prepared under NASA funding during the performance period.

NASA develops new digital flight control system

NASA Technical Reports Server (NTRS)

Mewhinney, Michael

1994-01-01

This news release reports on the development and testing of a new integrated flight and propulsion automated control system that aerospace engineers at NASA's Ames Research Center have been working on. The system is being tested in the V/STOL (Vertical/Short Takeoff and Landing) Systems Research Aircraft (VSRA).

RSRM nozzle actuator bracket/lug fracture mechanics qualification test

NASA Technical Reports Server (NTRS)

Kelley, Peggy

1993-01-01

This is the final report for the actuator bracket/lug fracture mechanics qualification test. The test plan (CTP-0071) outlined a two-phase test program designed to answer questions about the fracture criticality of the redesigned solid rocket motor (RSRM) nozzle actuator bracket. An analysis conducted using the NASA/FLAGRO fracture mechanics computer program indicated that the actuator bracket might be a fracture critical component. In the NASA/FLAGRO analysis, a simple lug model was used to represent the actuator bracket. It was calculated that the bracket would fracture if subjected to an actuator stall load in the presence of a 0.10 in. corner crack at the actuator attachment hole. The 0.10 in. crack size corresponds to the nondestructive inspection detectability limit for the actuator bracket. The inspection method used is the dye penetrant method. The actuator stall load (103,424 lb) is the maximum load which the actuator bracket is required to withstand during motor operation. This testing was designed to establish the accuracy of the analytical model and to directly determine whether the actuator bracket is capable of meeting fracture mechanics safe-life requirements.

Probabilistic Risk Assessment for Bone Fracture - Bone Fracture Risk Module (BFxRM)

NASA Technical Reports Server (NTRS)

Licata, Angelo; Myers, Jerry G.; Lewandowski, Beth

2013-01-01

This presentation summarizes the concepts, development, and application of NASA's Bone Fracture Risk Module (BFxRM). The overview includes an assessmnet of strenghts and limitations of the BFxRM and proposes a numebr of discussion questions to the panel regarding future development avenues for this simulation system.

Overview of Propulsion Controls and Diagnostics Research at NASA Glenn

NASA Technical Reports Server (NTRS)

Garg, Sanjay

2012-01-01

With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Branch (CDB) at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with other organizations within GRC and across NASA, the U.S. aerospace industry, and academia to develop advanced controls and health management technologies that will help meet these challenges through the concept of an Intelligent Engine. CDB conducts propulsion control and diagnostics research in support of various programs and projects under the NASA Aeronautics Research Mission Directorate and the Human Exploration and Operations Mission Directorate. The paper first provides an overview of the various research tasks in CDB relative to the NASA programs and projects, and briefly describes the progress being made on each of these tasks. The discussion here is at a high level providing the objectives of the tasks, the technical challenges in meeting the objectives and most recent accomplishments. References are provided for each of the technical tasks for the reader to familiarize themselves with the details.

NASA's OCA Mirroring System: An Application of Multiagent Systems in Mission Control

NASA Technical Reports Server (NTRS)

Sierhuis, Maarten; Clancey, William J.; vanHoof, Ron J. J.; Seah, Chin H.; Scott, Michael S.; Nado, Robert A.; Blumenberg, Susan F.; Shafto, Michael G.; Anderson, Brian L.; Bruins, Anthony C.;

Venus - Fractured Somerville Crater in Beta Regio

NASA Image and Video Library

1996-01-29

This radar image from NASA's Magellan spacecraft is of a half crater located in the rift between Rhea and Theia Montes in Beta Regio on Venus and has been cut by many fractures or faults since it was formed by the impact of a large asteroid. http://photojournal.jpl.nasa.gov/catalog/PIA00100

The control panel for the joint NASA/Gulfstream Quiet Spike project, located in the backseat of NASA's F-15B testbed aircraft

NASA Image and Video Library

2006-08-16

The control panel for the joint NASA/Gulfstream Quiet Spike project, located in the backseat of NASA's F-15B testbed aircraft. The project seeks to verify the structural integrity of the multi-segmented, articulating spike attachment designed to reduce and control a sonic boom.

Air Breathing Propulsion Controls and Diagnostics Research at NASA Glenn Under NASA Aeronautics Research Mission Programs

NASA Technical Reports Server (NTRS)

Garg, Sanjay

2014-01-01

This lecture will provide an overview of the aircraft turbine engine control research at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC). A brief introduction to the engine control problem is first provided with a description of the current state-of-the-art control law structure. A historical aspect of engine control development since the 1940s is then provided with a special emphasis on the contributions of GRC. The traditional engine control problem has been to provide a means to safely transition the engine from one steady-state operating point to another based on the pilot throttle inputs. With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Branch (CDB) at GRC is leading and participating in various projects in partnership with other organizations within GRC and across NASA, other government agencies, the U.S. aerospace industry, and academia to develop advanced propulsion controls and diagnostics technologies that will help meet the challenging goals of NASA programs under the Aeronautics Research Mission. The second part of the lecture provides an overview of the various CDB technology development activities in aircraft engine control and diagnostics, both current and some accomplished in the recent past. The motivation for each of the research efforts, the research approach, technical challenges and the key progress to date are summarized. The technologies to be discussed include system level engine control concepts, gas path diagnostics, active component control, and distributed engine control architecture. The lecture will end with a futuristic perspective of how the various current technology developments will lead to an Intelligent and Autonomous Propulsion System requiring none to very minimum pilot interface

[Damage Control Surgery in Polytrauma Patients with Pelvic Fractures. Is It Possible to Use Internal Fixation?

PubMed

Havlůj, L; Džupa, V; Gürlich, R

2017-01-01

Current polytrauma management is multidisciplinary, with Damage Control Surgery (DCS), Damage Control Orthopaedics (DCO) and Damage Control Resuscitation (DCR) being applied in the first few hours after injury. The most severe group of polytrauma patients are those with circulatory instability and massive blood loss as a consequence of unstable pelvic fractures. In treating these patients, of crucial importance is the speed and quality of stabilisation of pelvic fracture fragments. The authors present two case reports of polytrauma patients with unstable pelvic fractures, in whom open reduction and internal fixation was performed on the anterior fracture segment through extended laparotomy in order to stop bleeding into the abdominopelvic cavity as part of the DCS approach. Key words: exsanguination, polytrauma, unstable pelvic fracture, plate fixation.

Use of Organic Nitrates and the Risk of Hip Fracture: A Population-Based Case-Control Study

PubMed Central

Pouwels, Sander; Lalmohamed, Arief; van Staa, Tjeerd; Cooper, Cyrus; Souverein, Patrick; Leufkens, Hubertus G.; Rejnmark, Lars; de Boer, Anthonius; Vestergaard, Peter; de Vries, Frank

2010-01-01

Context: Use of organic nitrates has been associated with increased bone mineral density. Moreover, a large Danish case-control study reported a decreased fracture risk. However, the association with duration of nitrate use, dose frequency, and impact of discontinuation has not been extensively studied. Objective: Our objective was to evaluate the association between organic nitrates and hip fracture risk. Methods: A case-control study was conducted using the Dutch PHARMO Record Linkage System (1991–2002, n = 6,763 hip fracture cases and 26,341 controls). Cases had their first admission for hip fracture, whereas controls had not sustained any fracture after enrollment. Current users of organic nitrates were patients who had received a prescription within 90 d before the index date. The analyses were adjusted for disease and drug history. Results: Current use of nitrates was not associated with a decreased risk of hip fracture [adjusted odds ratio (OR) = 0.93; 95% confidence interval (CI) = 0.83–1.04]. Those who used as-needed medication only had a lower risk of hip fracture (adjusted OR = 0.83; 95% CI = 0.63–1.08) compared with users of maintenance medication only (adjusted OR = 1.17; 95% CI = 0.97–1.40). No association was found between duration of nitrate use and fracture risk. Conclusions: Our overall analyses showed that risk of a hip fracture was significantly lower among users of as-needed organic nitrates, when compared with users of maintenance medication. Our analyses of hip fracture risks with duration of use did not further support a beneficial effect of organic nitrates on hip fracture, although residual confounding may have masked beneficial effects. PMID:20130070

Use of organic nitrates and the risk of hip fracture: a population-based case-control study.

PubMed

Pouwels, Sander; Lalmohamed, Arief; van Staa, Tjeerd; Cooper, Cyrus; Souverein, Patrick; Leufkens, Hubertus G; Rejnmark, Lars; de Boer, Anthonius; Vestergaard, Peter; de Vries, Frank

2010-04-01

Use of organic nitrates has been associated with increased bone mineral density. Moreover, a large Danish case-control study reported a decreased fracture risk. However, the association with duration of nitrate use, dose frequency, and impact of discontinuation has not been extensively studied. Our objective was to evaluate the association between organic nitrates and hip fracture risk. A case-control study was conducted using the Dutch PHARMO Record Linkage System (1991-2002, n = 6,763 hip fracture cases and 26,341 controls). Cases had their first admission for hip fracture, whereas controls had not sustained any fracture after enrollment. Current users of organic nitrates were patients who had received a prescription within 90 d before the index date. The analyses were adjusted for disease and drug history. Current use of nitrates was not associated with a decreased risk of hip fracture [adjusted odds ratio (OR) = 0.93; 95% confidence interval (CI) = 0.83-1.04]. Those who used as-needed medication only had a lower risk of hip fracture (adjusted OR = 0.83; 95% CI = 0.63-1.08) compared with users of maintenance medication only (adjusted OR = 1.17; 95% CI = 0.97-1.40). No association was found between duration of nitrate use and fracture risk. Our overall analyses showed that risk of a hip fracture was significantly lower among users of as-needed organic nitrates, when compared with users of maintenance medication. Our analyses of hip fracture risks with duration of use did not further support a beneficial effect of organic nitrates on hip fracture, although residual confounding may have masked beneficial effects.

A Fractured Pole

NASA Image and Video Library

2015-10-15

NASA's Cassini spacecraft zoomed by Saturn's icy moon Enceladus on Oct. 14, 2015, capturing this stunning image of the moon's north pole. A companion view from the wide-angle camera (PIA20010) shows a zoomed out view of the same region for context. Scientists expected the north polar region of Enceladus to be heavily cratered, based on low-resolution images from the Voyager mission, but high-resolution Cassini images show a landscape of stark contrasts. Thin cracks cross over the pole -- the northernmost extent of a global system of such fractures. Before this Cassini flyby, scientists did not know if the fractures extended so far north on Enceladus. North on Enceladus is up. The image was taken in visible green light with the Cassini spacecraft narrow-angle camera. The view was acquired at a distance of approximately 4,000 miles (6,000 kilometers) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 9 degrees. Image scale is 115 feet (35 meters) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA19660

Application of characteristic time concepts for hydraulic fracture configuration design, control, and optimization. Final report

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

Advani, S.H.; Lee, T.S.; Moon, H.

1992-10-01

The analysis of pertinent energy components or affiliated characteristic times for hydraulic stimulation processes serves as an effective tool for fracture configuration designs optimization, and control. This evaluation, in conjunction with parametric sensitivity studies, provides a rational base for quantifying dominant process mechanisms and the roles of specified reservoir properties relative to controllable hydraulic fracture variables for a wide spectrum of treatment scenarios. Results are detailed for the following multi-task effort: (a) Application of characteristic time concept and parametric sensitivity studies for specialized fracture geometries (rectangular, penny-shaped, elliptical) and three-layered elliptic crack models (in situ stress, elastic moduli, and fracturemore » toughness contrasts). (b) Incorporation of leak-off effects for models investigated in (a). (c) Simulation of generalized hydraulic fracture models and investigation of the role of controllable vaxiables and uncontrollable system properties. (d) Development of guidelines for hydraulic fracture design and optimization.« less

NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST)

NASA Technical Reports Server (NTRS)

Gangloff, Richard P.; Scully, John R.; Stoner, Glenn E.; Thornton, Earl A.; Wawner, Franklin E., Jr.; Wert, John A.

1993-01-01

The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program continues a high level of activity. Progress achieved between 1 Jan. and 30 Jun. 1993 is reported. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites, and thermal gradient structures in collaboration with NASA-Langley researchers. The following projects are addressed: environmental fatigue of Al-Li-Cu alloys; mechanisms of localized corrosion and environmental fracture in Al-Cu-Li-Mg-Ag alloy X2095 and compositional variations; the effect of zinc additions on the precipitation and stress corrosion cracking behavior of alloy 8090; hydrogen interactions with Al-Li-Cu alloy 2090 and model alloys; metastable pitting of aluminum alloys; cryogenic fracture toughness of Al-Cu-Li + In alloys; the fracture toughness of Weldalite (TM); elevated temperature cracking of advanced I/M aluminum alloys; response of Ti-1100/SCS-6 composites to thermal exposure; superplastic forming of Weldalite (TM); research to incorporate environmental effects into fracture mechanics fatigue life prediction codes such as NASA FLAGRO; and thermoviscoplastic behavior.

Population screening for osteoporosis risk: a randomised control trial of medication use and fracture risk.

PubMed

Barr, R J; Stewart, A; Torgerson, D J; Reid, D M

2010-04-01

Randomised control trial of osteoporosis screening in 4,800 women aged 45-54 years was carried out. Screened group observed an increase of 7.9% in hormone replacement therapy (HRT) use (p < 0.001), 15% in other osteoporosis treatments (p < 0.001) and a 25.9% reduction in fracture risk compared with control. Screening for osteoporosis significantly increases treatment use and reduces fracture incidence. Population screening programmes can identify menopausal women with low bone mineral density (BMD) and elevated risk of future fracture but require to be proven effective by a randomised control trial. A total of 4,800 women, 45-54 years, were randomised in equal numbers to screening or no screening (control) groups. Following screening, those in the lowest quartile of BMD were advised to consider HRT. Nine years later, the effect of screening on the uptake of treatment and the incidence of fractures were assessed by postal questionnaire. Categorical differences were assessed using chi(2) test. Cox regression was used to assess hazard ratio (HR). Of the screened and the control groups, 52.4% vs 44.5%, respectively, reported taking HRT (p < 0.001). In addition, 36.6% of the screened vs 21.6% of the control groups reported the use of vitamin D, calcium, alendronate, etidronate or raloxifene (p < 0.001). In a per protocol analysis of verified incident fractures, a 25.9% reduction in risk of fractures (of any site) in the screened group was observed (HR = 0.741, 95% CI = 0.551-0.998 adjusted age, weight and height). Screening for osteoporosis as assessed by low bone density significantly increases the use of HRT and other treatments for osteoporosis and reduces fracture incidence.

Crustal Fractures of Ophir Planum

NASA Image and Video Library

2002-05-23

This NASA Mars Odyssey image covers a tract of plateau territory called Ophir Planum. The most obvious features in this scene are the fractures ranging from 1 to 5 km wide running from the upper left to lower right.

Control research in the NASA high-alpha technology program

NASA Technical Reports Server (NTRS)

Gilbert, William P.; Nguyen, Luat T.; Gera, Joseph

1990-01-01

NASA is conducting a focused technology program, known as the High-Angle-of-Attack Technology Program, to accelerate the development of flight-validated technology applicable to the design of fighters with superior stall and post-stall characteristics and agility. A carefully integrated effort is underway combining wind tunnel testing, analytical predictions, piloted simulation, and full-scale flight research. A modified F-18 aircraft has been extensively instrumented for use as the NASA High-Angle-of-Attack Research Vehicle used for flight verification of new methods and concepts. This program stresses the importance of providing improved aircraft control capabilities both by powered control (such as thrust-vectoring) and by innovative aerodynamic control concepts. The program is accomplishing extensive coordinated ground and flight testing to assess and improve available experimental and analytical methods and to develop new concepts for enhanced aerodynamics and for effective control, guidance, and cockpit displays essential for effective pilot utilization of the increased agility provided.

Overview of NASA's Environmental Control and Life Support Systems

NASA Technical Reports Server (NTRS)

Roman, Monserrate

2009-01-01

This viewgraph presentation reviews NASA's Environmental Control and Life Support Systems (ECLSS) on the International Space Station. A look inside of the International Space Station detailing ECLSS processes of controlling atmospheric pressure, conditioning the atmosphere, responding to emergency conditions, controlling internal carbon dioxide and contaminants and providing water are described. A detailed description of ISS Regenerative Environmental Control and Life Support System is also presented.

Spacecraft Hybrid Control At NASA: A Look Back, Current Initiatives, and Some Future Considerations

NASA Technical Reports Server (NTRS)

Dennehy, Neil

2014-01-01

There is a heightened interest within NASA for the design, development, and flight implementation of mixed actuator hybrid attitude control systems for science spacecraft that have less than three functional reaction wheel actuators. This interest is driven by a number of recent reaction wheels failures on aging, but still scientifically productive, NASA spacecraft. This paper describes the highlights of the first NASA Cross-Center Hybrid Control Workshop that was held in Greenbelt, Maryland in April of 2013 under the sponsorship of the NASA Engineering and Safety Center (NESC). A brief historical summary of NASA's past experiences with spacecraft mixed actuator hybrid attitude control approaches, some of which were implemented on-orbit, will be provided. This paper will also convey some of the lessons learned and best practices captured at that workshop. Some relevant recent and current hybrid control activities will be described with an emphasis on work in support of a repurposed Kepler spacecraft. Specific technical areas for future considerations regarding spacecraft hybrid control will also be identified.

Vision-based real-time position control of a semi-automated system for robot-assisted joint fracture surgery.

PubMed

Dagnino, Giulio; Georgilas, Ioannis; Tarassoli, Payam; Atkins, Roger; Dogramadzi, Sanja

2016-03-01

Joint fracture surgery quality can be improved by robotic system with high-accuracy and high-repeatability fracture fragment manipulation. A new real-time vision-based system for fragment manipulation during robot-assisted fracture surgery was developed and tested. The control strategy was accomplished by merging fast open-loop control with vision-based control. This two-phase process is designed to eliminate the open-loop positioning errors by closing the control loop using visual feedback provided by an optical tracking system. Evaluation of the control system accuracy was performed using robot positioning trials, and fracture reduction accuracy was tested in trials on ex vivo porcine model. The system resulted in high fracture reduction reliability with a reduction accuracy of 0.09 mm (translations) and of [Formula: see text] (rotations), maximum observed errors in the order of 0.12 mm (translations) and of [Formula: see text] (rotations), and a reduction repeatability of 0.02 mm and [Formula: see text]. The proposed vision-based system was shown to be effective and suitable for real joint fracture surgical procedures, contributing a potential improvement of their quality.

Effects of medication reviews performed by a physician on treatment with fracture-preventing and fall-risk-increasing drugs in older adults with hip fracture-a randomized controlled study.

PubMed

Sjöberg, Christina; Wallerstedt, Susanna M

2013-09-01

To investigate whether medication reviews increase treatment with fracture-preventing drugs and decrease treatment with fall-risk-increasing drugs. Randomized controlled trial (1:1). Departments of orthopedics, geriatrics, and medicine at Sahlgrenska University Hospital, Gothenburg, Sweden. One hundred ninety-nine consecutive individuals with hip fracture aged 65 and older. Medication reviews, based on assessments of risks of falls and fractures, regarding fracture-preventing and fall-risk-increasing drugs, performed by a physician, conveyed orally and in written form to hospital physicians during the hospital stay, and to general practitioners after discharge. Primary outcomes were changes in treatment with fracture-preventing and fall-risk-increasing drugs 12 months after discharge. Secondary outcomes were falls, fractures, deaths, and physicians' attitudes toward the intervention. At admission, 26% of intervention and 29% of control participants were taking fracture-preventing drugs, and 12% and 11%, respectively, were taking bone-active drugs, predominantly bisphosphonates. After 12 months, 77% of intervention and 58% of control participants were taking fracture-preventing drugs (P = .01), and 29% and 15%, respectively, were taking bone-active drugs (P = .04). Mean number of fall-risk-increasing drugs per participants was 3.1 (intervention) and 3.1 (control) at admission and 2.9 (intervention) and 3.1 (control) at 12 months (P = .62). No significant differences in hard endpoints were found. The responding physicians (n = 65) appreciated the intervention; on a scale from 1 (very bad) to 6 (very good), the median rating was 5 (interquartile range (IQR) 4-6) for the oral part and 5 (IQR 4-5.5) for the text part. Medication reviews performed and conveyed by a physician increased treatment with fracture-preventing drugs but did not significantly decrease treatment with fall-risk-increasing drugs in older adults with hip fracture. Prescribing physicians appreciated

A case study in technology utilization: Fracture mechanics

NASA Technical Reports Server (NTRS)

1972-01-01

This review of NASA contributions to the technology of fracture mechanics illustrates a fundamental role of the Space Agency in a single technical area. While primarily pursuing its goal of minimizing the weight of flight hardware, NASA engineers have generated innovations having broad impact in nonaerospace communities. A review is given of how these specific NASA innovations are communicated to the technical community outside the Space Agency, and current application areas are outlined.

Major factors controlling fracture development in the Middle Permian Lucaogou Formation tight oil reservoir, Junggar Basin, NW China

NASA Astrophysics Data System (ADS)

Zhang, Chen; Zhu, Deyu; Luo, Qun; Liu, Luofu; Liu, Dongdong; Yan, Lin; Zhang, Yunzhao

2017-09-01

Natural fractures in seven wells from the Middle Permian Lucaogou Formation in the Junggar Basin were evaluated in light of regional structural evolution, tight reservoir geochemistry (including TOC and mineral composition), carbon and oxygen isotopes of calcite-filled fractures, and acoustic emission (AE). Factors controlling the development of natural fractures were analyzed using qualitative and/or semi-quantitative techniques, with results showing that tectonic factors are the primary control on fracture development in the Middle Permian Lucaogou Formation of the Junggar Basin. Analyses of calcite, dolomite, and TOC show positive correlations with the number of fractures, while deltaic lithofacies appear to be the most favorable for fracture development. Mineral content was found to be a major control on tectonic fracture development, while TOC content and sedimentary facies mainly control bedding fractures. Carbon and oxygen isotopes vary greatly in calcite-filled fractures (δ13C ranges from 0.87‰ to 7.98‰, while δ18O ranges from -12.63‰ to -5.65‰), indicating that fracture development increases with intensified tectonic activity or enhanced diagenetic alteration. By analyzing the cross-cutting relationships of fractures in core, as well as four Kaiser Effect points in the acoustic emission curve, we observed four stages of tectonic fracture development. First-stage fractures are extensional, and were generated in the late Triassic, with calcite fracture fills formed between 36.51 °C and 56.89 °C. Second-stage fractures are shear fractures caused by extrusion stress from the southwest to the northeast, generated by the rapid uplift of the Tianshan in the Middle and Late Jurassic; calcite fracture fills formed between 62.91 °C and 69.88 °C. Third-stage fractures are NNW-trending shear fractures that resulted from north-south extrusion and thrusting in a foreland depression along the front of the Early Cretaceous Bogda Mountains. Calcite fracture

Relative Dating Via Fractures

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site]

This VIS image of the eastern part of the Tharsis region illustrates how fractures can be used in relative dating of a surface. The fractured materials on the right side of the image are embayed by younger volcanic flows originating to the west of the image. Note how the younger flows cover the ends of the fractures, and are not at all fractured themselves.

Image information: VIS instrument. Latitude 43.2, Longitude 269.4 East (90.6 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Vitamin D status among patients with hip fracture and elderly control subjects in Yekaterinburg, Russia.

PubMed

Bakhtiyarova, S; Lesnyak, O; Kyznesova, N; Blankenstein, M A; Lips, P

2006-01-01

Vitamin D deficiency leads to secondary hyperparathyroidism and osteomalacia, and both conditions are associated with fractures, the most severe being hip fracture. The serum 25-hydroxyvitamin D level depends on latitude and season. Yekaterinburg is situated at a high latitude and the duration of winter is about 5 months. In this study, the serum 25(OH)D and PTH concentrations, and the prevalence of hypovitaminosis D in elderly people, inhabitants of Yekaterinburg, were investigated. The study was performed on 63 people with hip fracture (mean age, 68.8 years) and 97 independently living elderly people (mean age, 70.2 years). Serum 25(OH)D (mean+/-SD) in the hip fracture group was 22.4+/-11.4 nmol/L, significantly lower than in control group, which was 28.1+/-10.1 nmol/L. The percentage of patients with severe hypovitaminosis D (<25 nmol/L) in the hip fracture group was 65%, compared to 47% in the control group (p<0.05). The prevalence of hypovitaminosis D among hip fracture patients, as well as among independently living elderly people in Yekaterinburg, was high. Supplementation of vitamin D in elderly people with and without fracture might prevent secondary hyperparathyroidism, osteomalacia and fractures.

Propulsion Controls and Diagnostics Research in Support of NASA Aeronautics and Exploration Mission Programs

NASA Technical Reports Server (NTRS)

Garg, Sanjay

2011-01-01

The Controls and Dynamics Branch (CDB) at National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with other organizations within GRC and across NASA, the U.S. aerospace industry, and academia to develop advanced propulsion controls and diagnostics technologies that will help meet the challenging goals of NASA programs under the Aeronautics Research and Exploration Systems Missions. This paper provides a brief overview of the various CDB tasks in support of the NASA programs. The programmatic structure of the CDB activities is described along with a brief overview of each of the CDB tasks including research objectives, technical challenges, and recent accomplishments. These tasks include active control of propulsion system components, intelligent propulsion diagnostics and control for reliable fault identification and accommodation, distributed engine control, and investigations into unsteady propulsion systems.

Current Level of Mission Control Automation at NASA/Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Maks, Lori; Breed, Julie; Rackley, Michael; Powers, Edward I. (Technical Monitor)

2001-01-01

NASA is particularly concerned with reducing mission operations costs through increased automation. This paper examines the operations procedures within NASA Mission Control Centers in order to uncover the level of automation that currently exists within them. Based on an assessment of mission operations procedures within three representative control centers, this paper recommends specific areas where there is potential for mission cost reduction through increased automation.

Advancing NASA's Satellite Control Capabilities: More than Just Better Technology

NASA Technical Reports Server (NTRS)

Smith, Danford

2008-01-01

This viewgraph presentation reviews the work of the Goddard Mission Services Evolution Center (GMSEC) in the development of the NASA's satellite control capabilities. The purpose of the presentation is to provide a quick overview of NASA's Goddard Space Flight Center and our approach to coordinating the ground system resources and development activities across many different missions. NASA Goddard's work in developing and managing the current and future space exploration missions is highlighted. The GMSEC, was established to to coordinate ground and flight data systems development and services, to create a new standard ground system for many missions and to reflect the reality that business reengineering and mindset were just as important.

A case-control study of quality of life and functional impairment in women with long-standing vertebral osteoporotic fracture.

PubMed

Hall, S E; Criddle, R A; Comito, T L; Prince, R L

1999-01-01

There have been several studies of the impact of vertebral osteoporotic fracture on the quality of life and functionality of individual subjects. To date, however, no direct comparisons with age-matched normal subjects without vertebral fracture have been made. The radiographs of 145 female clinic patients with vertebral fractures were reviewed by the study physicians. The controls were recruited from the electoral role and by media appeal. One hundred and sixty-seven women had radiographs taken to determine those without vertebral fracture. Fracture subjects and controls had to be ambulant and were excluded if they had significant radiologic evidence of degenerative disk or joint disease of the spine. One hundred cases and one hundred controls were matched by 5-year age groups. The number, position and severity of the vertebral fracture on the lateral radiographs of the cases was recorded. Quality of life was measured using the Short Form-36 (SF-36) (maximum score 100) and a utility score calculated from these results (maximum score 1). Two measurements of functionality were employed: the Modified Barthel Index (MBI) to assess the activities of daily living (maximum score 100) and the Timed 'Up & Go' (TUG) that measured the time taken for the subject to rise from sitting in a chair, walk 3 m along a line, return to the chair and sit down. The fracture subjects had 2.9 +/- 1.6 (mean +/- SD) vertebral fractures and the time since last fracture was 5.1 +/- 4.8 years. The SF-36 physical function component summary index results were: fracture subjects 36 +/- 11, controls 48 +/- 9 (p < 0.001). The SF-36 mental health component summary index results were: fracture subjects 50 +/- 11, controls 54 +/- 8 (p < 0.05). The utility scores were: fracture subjects 0.64 +/- 0.08, controls 0.72 +/- 0.07 (p < 0.001). The MBI results were: fracture subjects 97 +/- 5, controls 99 +/- 1 (p < 0.01). The TUG results were: fracture subjects 13.8 +/- 7.3 s, controls 10.1 +/- 4.1 s (p < 0

Sedimentological and Stratigraphic Controls on Natural Fracture Distribution in Wajid Group, SW Saudi Arabia

NASA Astrophysics Data System (ADS)

Benaafi, Mohammed; Hariri, Mustafa; Abdullatif, Osman; Makkawi, Mohammed; Korvin, Gabor

2016-04-01

The Cambro-Permian Wajid Group, SW Saudi Arabia, is the main groundwater aquifer in Wadi Al-Dawasir and Najran areas. In addition, it has a reservoir potentiality for oil and natural gas in Rub' Al-Khali Basin. Wajid Group divided into four formations, ascending Dibsiyah, Sanamah, Khussyayan and Juwayl. They are mainly sandstone and exposed in an area extend from Wadi Al-Dawasir southward to Najran city and deposited within fluvial, shallow marine and glacial environments. This study aims to investigate the sedimentological and stratigraphic controls on the distribution of natural fractures within Wajid Group outcrops. A scanline sampling method was used to study the natural fracture network within Wajid Group outcrops, where the natural fractures were measured and characterized in 12 locations. Four regional natural fracture sets were observed with mean strikes of 050o, 075o, 345o, and 320o. Seven lithofacies characterized the Wajid Group at these locations and include fine-grained sandstone, coarse to pebbly sandstone, cross-bedded sandstone, massive sandstone, bioturbated sandstone, conglomerate sandstone, and conglomerate lithofacies. We found that the fine-grained and small scale cross-bedded sandstones lithofacies are characterized by high fracture intensity. In contrast, the coarse-grained sandstone and conglomerate lithofacies have low fracture intensity. Therefore, the relative fracture intensity and spacing of natural fractures within Wajid Group in the subsurface can be predicted by using the lithofacies and their depositional environments. In terms of stratigraphy, we found that the bed thickness and the stratigraphic architecture are the main controls on fractures intensity. The outcomes of this study can help to understand and predict the natural fracture distribution within the subsurface fractured sandstone hosting groundwater and hydrocarbon in Wajid and Rub' Al-Khali Basins. Hence, the finding of this study might help to explore and develop the

A study of hydrogen environment effects on microstructure property behavior of NASA-23 alloy and related alloy systems

NASA Technical Reports Server (NTRS)

Diwan, Ravinder M.

1990-01-01

This work is part of the overall advanced main combustion chamber (AMCC) casting characterization program of the Materials and Processes Laboratory of the Marshall Space Flight Center. The influence of hydrogen on the tensile properties and ductility behavior of NASA-23 alloy were analyzed. NASA-23 and other referenced alloys in cast and hipped conditions were solution treated and aged under selected conditions and characterized using optical metallography, scanning electron microscopy, and electron microprobe analysis techniques. The yield strength of NASA-23 is not affected much by hydrogen under tensile tests carried at 5000 psig conditions; however, the ultimate strength and ductility properties are degraded. This implies that the physical mechanisms operating would be related to the plastic deformation process. The fracture surfaces characteristics of NASA-23 specimens tensile tested in hydrogen, helium, and air were also analyzed. These revealed surface cracks around specimen periphery with the fracture surface showing a combination of intergranular and transgranular modes of fracture. It is seen that the specimens charged in hydrogen seem to favor a more brittle fracture mode in comparison to air and helium charged specimens. The AMCC casting characterization program is to be analyzed for their hydrogen behavior. As a result of this program, the basic microstructural factors and fracture characteristics in some cases were analyzed.

A randomised controlled trial of low-dose aspirin for the prevention of fractures in healthy older people: protocol for the ASPREE-Fracture substudy.

PubMed

Barker, Anna L; McNeil, John J; Seeman, Ego; Ward, Stephanie A; Sanders, Kerrie M; Khosla, Sundeep; Cumming, Robert G; Pasco, Julie A; Bohensky, Megan A; Ebeling, Peter R; Woods, Robyn L; Lockery, Jessica E; Wolfe, Rory; Talevski, Jason

2016-08-01

Disability, mortality and healthcare burden from fractures in older people is a growing problem worldwide. Observational studies suggest that aspirin may reduce fracture risk. While these studies provide room for optimism, randomised controlled trials are needed. This paper describes the rationale and design of the ASPirin in Reducing Events in the Elderly (ASPREE)-Fracture substudy, which aims to determine whether daily low-dose aspirin decreases fracture risk in healthy older people. ASPREE is a double-blind, randomised, placebo-controlled primary prevention trial designed to assess whether daily active treatment using low-dose aspirin extends the duration of disability-free and dementia-free life in 19 000 healthy older people recruited from Australian and US community settings. This substudy extends the ASPREE trial data collection to determine the effect of daily low-dose aspirin on fracture and fall-related hospital presentation risk in the 16 500 ASPREE participants aged ≥70 years recruited in Australia. The intervention is a once daily dose of enteric-coated aspirin (100 mg) versus a matching placebo, randomised on a 1:1 basis. The primary outcome for this substudy is the occurrence of any fracture-vertebral, hip and non-vert-non-hip-occurring post randomisation. Fall-related hospital presentations are a secondary outcome. This substudy will determine whether a widely available, simple and inexpensive health intervention-aspirin-reduces the risk of fractures in older Australians. If it is demonstrated to safely reduce the risk of fractures and serious falls, it is possible that aspirin might provide a means of fracture prevention. The protocol for this substudy is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12615000347561). 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/

Evidence for tectonic, lithologic, and thermal controls on fracture system geometries in an andesitic high-temperature geothermal field

NASA Astrophysics Data System (ADS)

Massiot, Cécile; Nicol, Andrew; McNamara, David D.; Townend, John

2017-08-01

Analysis of fracture orientation, spacing, and thickness from acoustic borehole televiewer (BHTV) logs and cores in the andesite-hosted Rotokawa geothermal reservoir (New Zealand) highlights potential controls on the geometry of the fracture system. Cluster analysis of fracture orientations indicates four fracture sets. Probability distributions of fracture spacing and thickness measured on BHTV logs are estimated for each fracture set, using maximum likelihood estimations applied to truncated size distributions to account for sampling bias. Fracture spacing is dominantly lognormal, though two subordinate fracture sets have a power law spacing. This difference in spacing distributions may reflect the influence of the andesitic sequence stratification (lognormal) and tectonic faults (power law). Fracture thicknesses of 9-30 mm observed in BHTV logs, and 1-3 mm in cores, are interpreted to follow a power law. Fractures in thin sections (˜5 μm thick) do not fit this power law distribution, which, together with their orientation, reflect a change of controls on fracture thickness from uniform (such as thermal) controls at thin section scale to anisotropic (tectonic) at core and BHTV scales of observation. However, the ˜5% volumetric percentage of fractures within the rock at all three scales suggests a self-similar behavior in 3-D. Power law thickness distributions potentially associated with power law fluid flow rates, and increased connectivity where fracture sets intersect, may cause the large permeability variations that occur at hundred meter scales in the reservoir. The described fracture geometries can be incorporated into fracture and flow models to explore the roles of fracture connectivity, stress, and mineral precipitation/dissolution on permeability in such andesite-hosted geothermal systems.

NASA Glenn Research in Controls and Diagnostics for Intelligent Aerospace Propulsion Systems

NASA Technical Reports Server (NTRS)

2005-01-01

With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. Also the propulsion systems required to enable the NASA (National Aeronautics and Space Administration) Vision for Space Exploration in an affordable manner will need to have high reliability, safety and autonomous operation capability. The Controls and Dynamics Branch at NASA Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with other organizations within GRC and across NASA, the U.S. aerospace industry, and academia to develop advanced controls and health management technologies that will help meet these challenges through the concept of Intelligent Propulsion Systems. The key enabling technologies for an Intelligent Propulsion System are the increased efficiencies of components through active control, advanced diagnostics and prognostics integrated with intelligent engine control to enhance operational reliability and component life, and distributed control with smart sensors and actuators in an adaptive fault tolerant architecture. This paper describes the current activities of the Controls and Dynamics Branch in the areas of active component control and propulsion system intelligent control, and presents some recent analytical and experimental results in these areas.

Effect of Control Mode and Test Rate on the Measured Fracture Toughness of Advanced Ceramics

NASA Technical Reports Server (NTRS)

Hausmann, Bronson D.; Salem, Jonathan A.

2018-01-01

The effects of control mode and test rate on the measured fracture toughness of ceramics were evaluated by using chevron-notched flexure specimens in accordance with ASTM C1421. The use of stroke control gave consistent results with about 2% (statistically insignificant) variation in measured fracture toughness for a very wide range of rates (0.005 to 0.5 mm/min). Use of strain or crack mouth opening displacement (CMOD) control gave approx. 5% (statistically significant) variation over a very wide range of rates (1 to 80 µm/m/s), with the measurements being a function of rate. However, the rate effect was eliminated by use of dry nitrogen, implying a stress corrosion effect rather than a stability effect. With the use of a nitrogen environment during strain controlled tests, fracture toughness values were within about 1% over a wide range of rates (1 to 80 micons/m/s). CMOD or strain control did allow stable crack extension well past maximum force, and thus is preferred for energy calculations. The effort is being used to confirm recommendations in ASTM Test Method C1421 on fracture toughness measurement.

Aircraft Turbine Engine Control Research at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Garg, Sanjay

2014-01-01

This lecture will provide an overview of the aircraft turbine engine control research at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC). A brief introduction to the engine control problem is first provided with a description of the current state-of-the-art control law structure. A historical aspect of engine control development since the 1940s is then provided with a special emphasis on the contributions of GRC. The traditional engine control problem has been to provide a means to safely transition the engine from one steady-state operating point to another based on the pilot throttle inputs. With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Branch (CDB) at GRC is leading and participating in various projects in partnership with other organizations within GRC and across NASA, other government agencies, the U.S. aerospace industry, and academia to develop advanced propulsion controls and diagnostics technologies that will help meet the challenging goals of NASA programs under the Aeronautics Research Mission. The second part of the lecture provides an overview of the various CDB technology development activities in aircraft engine control and diagnostics, both current and some accomplished in the recent past. The motivation for each of the research efforts, the research approach, technical challenges and the key progress to date are summarized. The technologies to be discussed include system level engine control concepts, gas path diagnostics, active component control, and distributed engine control architecture. The lecture will end with a futuristic perspective of how the various current technology developments will lead to an Intelligent and Autonomous Propulsion System requiring none to very minimum pilot interface

Aircraft Turbine Engine Control Research at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Garg, Sanjay

2013-01-01

This paper provides an overview of the aircraft turbine engine control research at the NASA Glenn Research Center (GRC). A brief introduction to the engine control problem is first provided with a description of the state-of-the-art control law structure. A historical aspect of engine control development since the 1940s is then provided with a special emphasis on the contributions of GRC. With the increased emphasis on aircraft safety, enhanced performance, and affordability, as well as the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Branch (CDB) at GRC is leading and participating in various projects to develop advanced propulsion controls and diagnostics technologies that will help meet the challenging goals of NASA Aeronautics Research Mission programs. The rest of the paper provides an overview of the various CDB technology development activities in aircraft engine control and diagnostics, both current and some accomplished in the recent past. The motivation for each of the research efforts, the research approach, technical challenges, and the key progress to date are summarized.

A Flight Control System Architecture for the NASA AirSTAR Flight Test Infrastructure

NASA Technical Reports Server (NTRS)

Murch, Austin M.

2008-01-01

A flight control system architecture for the NASA AirSTAR infrastructure has been designed to address the challenges associated with safe and efficient flight testing of research control laws in adverse flight conditions. The AirSTAR flight control system provides a flexible framework that enables NASA Aviation Safety Program research objectives, and includes the ability to rapidly integrate and test research control laws, emulate component or sensor failures, inject automated control surface perturbations, and provide a baseline control law for comparison to research control laws and to increase operational efficiency. The current baseline control law uses an angle of attack command augmentation system for the pitch axis and simple stability augmentation for the roll and yaw axes.

A Hierarchical Approach to Fracture Mechanics

NASA Technical Reports Server (NTRS)

Saether, Erik; Taasan, Shlomo

2004-01-01

Recent research conducted under NASA LaRC's Creativity and Innovation Program has led to the development of an initial approach for a hierarchical fracture mechanics. This methodology unites failure mechanisms occurring at different length scales and provides a framework for a physics-based theory of fracture. At the nanoscale, parametric molecular dynamic simulations are used to compute the energy associated with atomic level failure mechanisms. This information is used in a mesoscale percolation model of defect coalescence to obtain statistics of fracture paths and energies through Monte Carlo simulations. The mathematical structure of predicted crack paths is described using concepts of fractal geometry. The non-integer fractal dimension relates geometric and energy measures between meso- and macroscales. For illustration, a fractal-based continuum strain energy release rate is derived for inter- and transgranular fracture in polycrystalline metals.

Publications of the NASA Controlled Ecological Life Support Systems (CELSS) Program 1984-86

NASA Technical Reports Server (NTRS)

1987-01-01

Publications of research sponsored by the NASA CELSS (Controlled Ecological Life Support Systems) Program are listed, along with publications of interest to the Program. The bibliography is divided into the three major divisions of CELSS research: (1) Food Production; (2) Waste Management; and (3) Systems Management and Control. This bibliography is an update of NASA CR-3911 and includes references from 1984 through 1986.

Determining Desirable Cursor Control Device Characteristics for NASA Exploration Missions

NASA Technical Reports Server (NTRS)

Sandor, Aniko; Holden, Kritina L.

2007-01-01

A test battery was developed for cursor control device evaluation: four tasks were taken from ISO 9241-9, and three from previous studies conducted at NASA. The tasks focused on basic movements such as pointing, clicking, and dragging. Four cursor control devices were evaluated with and without Extravehicular Activity (EVA) gloves to identify desirable cursor control device characteristics for NASA missions: 1) the Kensington Expert Mouse, 2) the Hulapoint mouse, 3) the Logitech Marble Mouse, and 4) the Honeywell trackball. Results showed that: 1) the test battery is an efficient tool for differentiating among input devices, 2) gloved operations were about 1 second slower and had at least 15% more errors; 3) devices used with gloves have to be larger, and should allow good hand positioning to counteract the lack of tactile feedback, 4) none of the devices, as designed, were ideal for operation with EVA gloves.

Multiwell fracturing experiments. [Nitrogen foam fracture treatment

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

Warpinski, N.

The objective of the Multiwell fracturing experiments is to test and develop the technology for the efficient stimulation of tight, lenticular gas sands. This requires basic understanding of: (1) fracture behavior and geometry in this complex lithologic environment, and (2) subsequent production into the created fracture. The intricate interplay of the hydraulic fracture with the lens geometry, the internal reservoir characteristics (fractures, reservoir breaks, etc.), the in situ stresses, and the mechanical defects (fracture, bedding, etc.) need to be defined in order to develop a successful stimulation program. The stimulation phase of the Multiwell Experiment is concerned with: (1) determiningmore » important rock/reservoir properties that influence or control fracture geometry and behavior, (2) designing fracture treatments to achieve a desired size and objectives, and (3) conducting post-treatment analyses to evaluate the effectiveness of the treatment. Background statement, project description, results and evaluation of future plans are presented. 5 refs., 2 figs., 2 tabs.« less

Experimental Investigation on the Basic Law of Directional Hydraulic Fracturing Controlled by Dense Linear Multi-Hole Drilling

NASA Astrophysics Data System (ADS)

Zhao, Xinglong; Huang, Bingxiang; Wang, Zhen

2018-06-01

Directional rupture is a significant and routine problem for ground control in mines. Directional hydraulic fracturing controlled by dense linear multi-hole drilling was proposed. The physical model experiment, performed by the large-scale true triaxial hydraulic fracturing experimental system, aims to investigate the basic law of directional hydraulic fracturing controlled by dense linear multi-hole drilling, the impact of three different pumping modes on the initiation and propagation of hydraulic fractures among boreholes are particular investigated. The experimental results indicated that there are mutual impacts among different boreholes during crack propagation, which leads to a trend of fracture connection. Furthermore, during propagation, the fractures not only exhibit an overall bias toward the direction in which the boreholes are scattered but also partially offset against the borehole axes and intersect. The directional fracturing effect of equivalent pumping rate in each borehole is better than the other two pumping modes. In practical applications, because of rock mass heterogeneity, there may be differences in terms of filtration rate and effective input volume in different boreholes; thus, water pressure increase and rupture are not simultaneous in different boreholes. Additionally, if the crack initiation directions of different boreholes at different times are not consistent with each other, more lamellar failure planes will occur, and the mutual influences of these lamellar failure planes cause fractures to extend and intersect.

Screening in the community to reduce fractures in older women (SCOOP): a randomised controlled trial.

PubMed

Shepstone, Lee; Lenaghan, Elizabeth; Cooper, Cyrus; Clarke, Shane; Fong-Soe-Khioe, Rebekah; Fordham, Richard; Gittoes, Neil; Harvey, Ian; Harvey, Nick; Heawood, Alison; Holland, Richard; Howe, Amanda; Kanis, John; Marshall, Tarnya; O'Neill, Terence; Peters, Tim; Redmond, Niamh; Torgerson, David; Turner, David; McCloskey, Eugene

2018-02-24

Despite effective assessment methods and medications targeting osteoporosis and related fractures, screening for fracture risk is not currently advocated in the UK. We tested whether a community-based screening intervention could reduce fractures in older women. We did a two-arm randomised controlled trial in women aged 70-85 years to compare a screening programme using the Fracture Risk Assessment Tool (FRAX) with usual management. Women were recruited from 100 general practitioner (GP) practices in seven regions of the UK: Birmingham, Bristol, Manchester, Norwich, Sheffield, Southampton, and York. We excluded women who were currently on prescription anti-osteoporotic drugs and any individuals deemed to be unsuitable to enter a research study (eg, known dementia, terminally ill, or recently bereaved). The primary outcome was the proportion of individuals who had one or more osteoporosis-related fractures over a 5-year period. In the screening group, treatment was recommended in women identified to be at high risk of hip fracture, according to the FRAX 10-year hip fracture probability. Prespecified secondary outcomes were the proportions of participants who had at least one hip fracture, any clinical fracture, or mortality; and the effect of screening on anxiety and health-related quality of life. This trial is registered with the International Standard Randomised Controlled Trial registry, number ISRCTN 55814835. 12 483 eligible women were identified and participated in the trial, and 6233 women randomly assigned to the screening group between April 15, 2008, and July 2, 2009. Treatment was recommended in 898 (14%) of 6233 women. Use of osteoporosis medication was higher at the end of year 1 in the screening group compared with controls (15% vs 4%), with uptake particularly high (78% at 6 months) in the screening high-risk subgroup. Screening did not reduce the primary outcome of incidence of all osteoporosis-related fractures (hazard ratio [HR] 0·94, 95% CI 0�

Development of the NASA/FLAGRO computer program for analysis of airframe structures

NASA Technical Reports Server (NTRS)

Forman, R. G.; Shivakumar, V.; Newman, J. C., Jr.

1994-01-01

The NASA/FLAGRO (NASGRO) computer program was developed for fracture control analysis of space hardware and is currently the standard computer code in NASA, the U.S. Air Force, and the European Agency (ESA) for this purpose. The significant attributes of the NASGRO program are the numerous crack case solutions, the large materials file, the improved growth rate equation based on crack closure theory, and the user-friendly promptive input features. In support of the National Aging Aircraft Research Program (NAARP); NASGRO is being further developed to provide advanced state-of-the-art capability for damage tolerance and crack growth analysis of aircraft structural problems, including mechanical systems and engines. The project currently involves a cooperative development effort by NASA, FAA, and ESA. The primary tasks underway are the incorporation of advanced methodology for crack growth rate retardation resulting from spectrum loading and improved analysis for determining crack instability. Also, the current weight function solutions in NASGRO or nonlinear stress gradient problems are being extended to more crack cases, and the 2-d boundary integral routine for stress analysis and stress-intensity factor solutions is being extended to 3-d problems. Lastly, effort is underway to enhance the program to operate on personal computers and work stations in a Windows environment. Because of the increasing and already wide usage of NASGRO, the code offers an excellent mechanism for technology transfer for new fatigue and fracture mechanics capabilities developed within NAARP.

Probabilistic Risk Assessment for Astronaut Post Flight Bone Fracture

NASA Technical Reports Server (NTRS)

Lewandowski, Beth; Myers, Jerry; Licata, Angelo

2015-01-01

Introduction: Space flight potentially reduces the loading that bone can resist before fracture. This reduction in bone integrity may result from a combination of factors, the most common reported as reduction in astronaut BMD. Although evaluating the condition of bones continues to be a critical aspect of understanding space flight fracture risk, defining the loading regime, whether on earth, in microgravity, or in reduced gravity on a planetary surface, remains a significant component of estimating the fracture risks to astronauts. This presentation summarizes the concepts, development, and application of NASA's Bone Fracture Risk Module (BFxRM) to understanding pre-, post, and in mission astronaut bone fracture risk. The overview includes an assessment of contributing factors utilized in the BFxRM and illustrates how new information, such as biomechanics of space suit design or better understanding of post flight activities may influence astronaut fracture risk. Opportunities for the bone mineral research community to contribute to future model development are also discussed. Methods: To investigate the conditions in which spaceflight induced changes to bone plays a critical role in post-flight fracture probability, we implement a modified version of the NASA Bone Fracture Risk Model (BFxRM). Modifications included incorporation of variations in physiological characteristics, post-flight recovery rate, and variations in lateral fall conditions within the probabilistic simulation parameter space. The modeled fracture probability estimates for different loading scenarios at preflight and at 0 and 365 days post-flight time periods are compared. Results: For simple lateral side falls, mean post-flight fracture probability is elevated over mean preflight fracture probability due to spaceflight induced BMD loss and is not fully recovered at 365 days post-flight. In the case of more energetic falls, such as from elevated heights or with the addition of lateral movement

Dark, Thin Fracture-Filling Material

NASA Image and Video Library

2015-11-11

These images and overlay bar charts from the Chemistry and Camera (ChemCam) instrument on NASA's Curiosity Mars rover indicate where some high-potassium material is localized within mineral veins at "Garden City." The two images are from ChemCam's Remote Micro-Imager. Each covers an area just over an inch wide (scale bars are in millimeters) in veins at the Garden City site on lower Mount Sharp. The overlay charts show comparisons of potassium (blue) and iron (red) in the mineral veins' compositions determined by reading the spectra of light induced by zapping points in each area with ChemCam's laser. Mineral veins such as these form where fluids move through fractured rocks, depositing minerals in the fractures and affecting chemistry of the surrounding rock. The thin layer of dark fracture-filling material in the image on the right contains much more potassium than the other local material on the left, indicating either different fluid compositions or local variations in the rock. The image on the left was taken on April 4, 2015, during the 946th Martian day, or sol, of Curiosity's work on Mars. The image on the right was taken on Sol 936, on March 25, 2015. A broader view of the prominent mineral veins at Garden City is at PIA19161. http://photojournal.jpl.nasa.gov/catalog/PIA19923

Numerical examination of the factors controlling DNAPL migration through a single fracture.

PubMed

Reynolds, D A; Kueper, B H

2002-01-01

The migration of five dense nonaqueous phase liquids (DNAPLs) through a single fracture in a clay aquitard was numerically simulated with the use of a compositional simulator. The effects of fracture aperture, fracture dip, matrix porosity, and matrix organic carbon content on the migration of chlorobenzene, 1,2-dichloroethylene, trichloroethylene, tetra-chloroethylene, and 1,2-dibromoethane were examined. Boundary conditions were chosen such that DNAPL entry into the system was allowed to vary according to the stresses applied. The aperture is the most important factor of those studied controlling the migration rate of DNAPL through a single fracture embedded in a clay matrix. Loss of mass to the matrix through diffusion does not significantly retard the migration rate of the DNAPL, particularly in larger aperture fractures (e.g., 50 microm). With time, the ratio of diffusive loss to the matrix to DNAPL flux into the fracture approaches an asymptotic value lower than unity. The implication is that matrix diffusion cannot arrest the migration of DNAPL in a single fracture. The complex relationships between density, viscosity, and solubility that, to some extent, govern the migration of DNAPL through these systems prevent accurate predictions without the use of numerical models. The contamination potential of the migrating DNAPL is significantly increased through the transfer of mass to the matrix. The occurrence of opposite concentration gradients within the matrix can cause dissolved phase contamination to exist in the system for more than 1000 years after the DNAPL has been completely removed from the fracture.

Flight Test of Composite Model Reference Adaptive Control (CMRAC) Augmentation Using NASA AirSTAR Infrastructure

NASA Technical Reports Server (NTRS)

Gregory, Irene M.; Gadient, ROss; Lavretsky, Eugene

2011-01-01

This paper presents flight test results of a robust linear baseline controller with and without composite adaptive control augmentation. The flight testing was conducted using the NASA Generic Transport Model as part of the Airborne Subscale Transport Aircraft Research system at NASA Langley Research Center.

Design and real-time control of a robotic system for fracture manipulation.

PubMed

Dagnino, G; Georgilas, I; Tarassoli, P; Atkins, R; Dogramadzi, S

2015-08-01

This paper presents the design, development and control of a new robotic system for fracture manipulation. The objective is to improve the precision, ergonomics and safety of the traditional surgical procedure to treat joint fractures. The achievements toward this direction are here reported and include the design, the real-time control architecture and the evaluation of a new robotic manipulator system. The robotic manipulator is a 6-DOF parallel robot with the struts developed as linear actuators. The control architecture is also described here. The high-level controller implements a host-target structure composed by a host computer (PC), a real-time controller, and an FPGA. A graphical user interface was designed allowing the surgeon to comfortably automate and monitor the robotic system. The real-time controller guarantees the determinism of the control algorithms adding an extra level of safety for the robotic automation. The system's positioning accuracy and repeatability have been demonstrated showing a maximum positioning RMSE of 1.18 ± 1.14mm (translations) and 1.85 ± 1.54° (rotations).

[Damage control resuscitation of severe multiple trauma in the pelvic fractures].

PubMed

Fu, Chang-guo

2015-05-01

To discuss the clinical effects of damage control resuscitation (DCR) in treating severe multiple trauma in the pelvic fractures. From March 2009 to September 2013, a restrospective analysis was conducted on the clinical data of 28 patients with multiple trauma in the pelvic fractures, including 19 males and 9 females, ranging in age from 21 to 51 years old with an average of 32.5 years old. According to Tile classification of pelvic fractures, 16 cases were type B and 12 cases were type C. Injury severity score (ISS) averaged 32.0±3.4. All cases were treated with damage contral orthopaedics and DCR strategy, namely that used immediately with small capacity of balanced salt solution on admission so as to maintain the blood pressure between 80 to 90 mmHg. At the same time, emergency phase I simple debridement plus external fixator or bundled with fixed pelvic was done, and the chest or abdomen combined injury was treated at first. And limbs fracture was temporary dealing with bone traction or plaster external fixation, etc. After bleeding was controlled by operation, fluid resuscitation was done as fast as possible and the plasma was transfused early according to the proportion of plasma and red cell suspension (2 U:1 U-3 U:2 U). Dosage of balanced salt solution and blood before remedy shock was recorded, and the removal of time of lactic acid and coagulation were observed. Five cases were died after 4 to 15 hours into hospital (3 cases died for severe trauma-hemorrhagic shock and 2 cases for acute respiratory distress syndrome). Twenty-three cases were remedy shock at 1.6 to 4.3 hours after injury with an average of 2.4 hours. Period I operation duration was (78.2±10.3) minutes. Dosage of balanced salt solution was (3,798±340) ml and red cell suspension was 14 to 18 U, fresh frozen plasma (FFP) was (1,267±58) ml (1U FFP=100 ml), blood platelet was 8 to 12 U for 9 patients. The removal time of lactic acid and PT-APTT was (11.4±2.1) hours and (4.3±0.8) hours

Controls on Permeability Evolution in Fractured-Sorbing Media

NASA Astrophysics Data System (ADS)

Elsworth, D.

2017-12-01

A critical component in the desire to recover energy and fuels from the subsurface, or to sequester energy-related and other wastes, is the ability to control properties that influence the transport and storage of mass, fluids and energy. In fractured media, permeabilities are strongly dependent on effective stresses. In turn, effective stresses (M) are mediated by changes in fluid pressures (H), compositions of the permeating fluids and permeated rocks (C) and changes in temperature (T) - and sometimes influenced by biological (B) processes. First we explore the role of specific complex THMC(B) interactions in mediating changes in permeability in response to a change in spherical stress. These include the roles of differential strains, induced within shales by changes in pressure (H), gas concentration (C) or temperature (T), in driving changes in permeability, in particular where the effects of sorption are pronounced. We show that the influence of such pressure-, sorption- and thermally-induced changes in damage and porosity are countered, by the first order resetting effects of creep that influence the crack distribution within the fractured aggregate. Second, we explore linkages where friction and instability control the response to changes in differential stress. Changes in permeability are controlled by styles of deformation - brittle versus ductile - with modes of deformation in turn mediated by mineralogy of both native and altered mineral constituents, the evolving scale of deformation and in the progress of deformation through the dynamic loading cycle.

Cross-education for improving strength and mobility after distal radius fractures: a randomized controlled trial.

PubMed

Magnus, Charlene R A; Arnold, Cathy M; Johnston, Geoffrey; Dal-Bello Haas, Vanina; Basran, Jenny; Krentz, Joel R; Farthing, Jonathan P

2013-07-01

To evaluate the effects of cross-education (contralateral effect of unilateral strength training) during recovery from unilateral distal radius fractures on muscle strength, range of motion (ROM), and function. Randomized controlled trial (26-wk follow-up). Hospital, orthopedic fracture clinic. Women older than 50 years with a unilateral distal radius fracture. Fifty-one participants were randomized and 39 participants were included in the final data analysis. Participants were randomized to standard rehabilitation (Control) or standard rehabilitation plus strength training (Train). Standard rehabilitation included forearm casting for 40.4±6.2 days and hand exercises for the fractured extremity. Nonfractured hand strength training for the training group began immediately postfracture and was conducted at home 3 times/week for 26 weeks. The primary outcome measure was peak force (handgrip dynamometer). Secondary outcomes were ROM (flexion/extension; supination/pronation) via goniometer and the Patient Rated Wrist Evaluation questionnaire score for the fractured arm. For the fractured hand, the training group (17.3±7.4kg) was significantly stronger than the control group (11.8±5.8kg) at 12 weeks postfracture (P<.017). There were no significant strength differences between the training and control groups at 9 (12.5±8.2kg; 11.3±6.9kg) or 26 weeks (23.0±7.6kg; 19.6±5.5kg) postfracture, respectively. Fractured hand ROM showed that the training group had significantly improved wrist flexion/extension (100.5°±19.2°) than the control group (80.2°±18.7°) at 12 weeks postfracture (P<.017). There were no significant differences between the training and control groups for flexion/extension ROM at 9 (78.0°±20.7°; 81.7°±25.7°) or 26 weeks (104.4°±15.5°; 106.0°±26.5°) or supination/pronation ROM at 9 (153.9°±23.9°; 151.8°±33.0°), 12 (170.9°±9.3°; 156.7°±20.8°) or 26 weeks (169.4°±11.9°; 162.8°±18.1°), respectively. There were no

Extensive Ice Fractures in the Beaufort Sea

NASA Image and Video Library

2017-12-08

much heat the surface was emitting as VIIRS surveyed the area. Cooler areas (sea ice) appear white, while warmer areas (open water) are dark. The light gray plume near the cracks is warmer, moister air escaping from the ocean and blowing downwind. Clouds do not show up well in the VIIRS thermal band, so the storms that fueled the fracturing are not readily visible. While fracturing events are common, few events sprawl across such a large area or produce cracks as long and wide as those seen here. The age of the sea ice in this area was one of the key reasons this event became so widespread. “The region is covered almost completely by seasonal or first-year ice—ice that has formed since last September,” said Meier. “This ice is thinner and weaker than the older, multi-year ice, so it responds more readily to winds and is more easily broken up.” NASA Earth Observatory images by Jesse Allen using VIIRS day-night band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Adam Voiland. Instrument: Suomi NPP - VIIRS For more info go to: earthobservatory.nasa.gov/IOTD/view.php?id=80752 Credit: NASA Earth Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Fourth NASA Workshop on Computational Control of Flexible Aerospace Systems, part 2

NASA Technical Reports Server (NTRS)

Taylor, Lawrence W., Jr. (Compiler)

1991-01-01

A collection of papers presented at the Fourth NASA Workshop on Computational Control of Flexible Aerospace Systems is given. The papers address modeling, systems identification, and control of flexible aircraft, spacecraft and robotic systems.

The planning and control of NASA programs and resources

NASA Technical Reports Server (NTRS)

1983-01-01

The major management systems used to plan and control NASA programs and resources are described as well as their integration to form the agency's general management approach in carrying out its mission. Documents containing more detailed descriptions of the processes and techniques involved in the agency's major management systems are listed.

Bisphosphonates for the prevention of fractures in osteogenesis imperfecta: meta-analysis of placebo-controlled trials.

PubMed

Hald, Jannie D; Evangelou, Evangelos; Langdahl, Bente L; Ralston, Stuart H

2015-05-01

Bisphosphonates are widely used off-label in the treatment of patients with osteogenesis imperfecta (OI) with the intention of reducing the risk of fracture. Although there is strong evidence that bisphosphonates increase bone mineral density in osteogenesis imperfecta, the effects on fracture occurrence have been inconsistent. The aim of this study was to gain a better insight into the effects of bisphosphonate therapy on fracture risk in patients with osteogenesis imperfecta by conducting a meta-analysis of randomized controlled trials in which fractures were a reported endpoint. We searched Medline, Embase, and the Cochrane Central Register of Controlled Trials in which the effects of bisphosphonates on fracture risk in osteogenesis imperfecta were compared with placebo and conducted a meta-analysis of these studies using standard methods. Heterogeneity was assessed using the I2 statistic. Six eligible studies were identified involving 424 subjects with 751 patient-years of follow-up. The proportion of patients who experienced a fracture was not significantly reduced by bisphosphonate therapy (Relative Risk [RR] = 0.83 [95% confidence interval 0.69-1.01], p = 0.06) with no heterogeneity between studies (I2  = 0). The fracture rate was reduced by bisphosphonate treatment when all studies were considered (RR = 0.71 [0.52-0.96], p = 0.02), but with considerable heterogeneity (I2  = 36%) explained by one study where a small number of patients in the placebo group experienced a large number of fractures. When this study was excluded, the effects of bisphosphonates on fracture rate was not significant (RR = 0.79 [0.61-1.02], p = 0.07, I2  = 0%). We conclude that the effects of bisphosphonates on fracture prevention in osteogenesis imperfecta are inconclusive. Adequately powered trials with a fracture endpoint are needed to further investigate the risks and benefits of bisphosphonates in this condition. © 2014 American Society for

Control-Structure-Interaction (CSI) technologies and trends to future NASA missions

NASA Technical Reports Server (NTRS)

1990-01-01

Control-structure-interaction (CSI) issues which are relevant for future NASA missions are reviewed. This goal was achieved by: (1) reviewing large space structures (LSS) technologies to provide a background and survey of the current state of the art (SOA); (2) analytically studying a focus mission to identify opportunities where CSI technology may be applied to enhance or enable future NASA spacecraft; and (3) expanding a portion of the focus mission, the large antenna, to provide in-depth trade studies, scaling laws, and methodologies which may be applied to other NASA missions. Several sections are presented. Section 1 defines CSI issues and presents an overview of the relevant modeling and control issues for LLS. Section 2 presents the results of the three phases of the CSI study. Section 2.1 gives the results of a CSI study conducted with the Geostationary Platform (Geoplat) as the focus mission. Section 2.2 contains an overview of the CSI control design methodology available in the technical community. Included is a survey of the CSI ground-based experiments which were conducted to verify theoretical performance predictions. Section 2.3 presents and demonstrates a new CSI scaling law methodology for assessing potential CSI with large antenna systems.

Postmenopausal women with osteopenia and a healed wrist fracture have reduced physical function and quality of life compared to a matched, healthy control group with no fracture

PubMed Central

2014-01-01

Background Fractures lead to reduced physical function and quality of life (QOL), but little is known about postmenopausal women with osteopenia and a healed wrist fracture. The purpose was to evaluate physical function in terms of quadriceps strength, dynamic balance, physical capacity and QOL in postmenopausal women with osteopenia and a healed wrist fracture compared to a matched, healthy control group with no previous fracture. Methods Eighteen postmenopausal women with osteopenia (patients) (mean age 59.1 years, range 54 – 65) and a healed wrist fracture were matched to 18 healthy control subjects on age (mean age 58.5 years, range 51 – 65), height, weight and body mass index (BMI). We measured quadriceps strength at 60°/sec and at 180°/sec with Biodex 6000, dynamic balance with the Four Square Step Test (FSST), physical capacity with the six-minute walk test (6MWT) followed by the Borg’s scale (BS), and QOL with the Short Form 36 (SF-36), bone mineral density (BMD) with dual x-ray absorptiometry (DXA) and physical activity level with the Physical Activity Scale for the Elderly. Results The patients had 17.6% lower quadriceps strength at 60°/sec (p = 0.025) at left limb and 18.5% at 180°/sec (p = 0.016) at right limb, and 21% lower at 180°/sec (p = 0.010) at left limb compared to the controls. Impaired performance for the patients was found with 2.4 seconds (p = 0.002) on the FSST, 74 metres (p < 0.001) on the 6MWT, and 1.4 points (p = 0.003) on the BS compared to the controls. The patients scored lower on the sub-scales on the SF-36 role limitations-physical (p = 0.014), bodily pain (p = 0.025) and vitality (p = 0.015) compared to the controls. Conclusions The patients with osteopenia and a healed wrist fracture scored significantly lower on quadriceps strength, dynamic balance, physical capacity and QOL compared to the matched controls. Greater focus should be put on this patient group in terms of

[Distal radius fractures--retrospective quality control after conservative and operative therapy].

PubMed

Sommer, C; Brendebach, L; Meier, R; Leutenegger, A

2001-01-01

The distal radius fracture is the most frequent fracture in the adult patient. The wide spectrum of different types of fracture and the coexisting factors make the choice for the optimal treatment difficult. As an interne quality control we retrospectively evaluated all patients with distal radius fractures treated in 1995 at our institution. The study included 69 adult patients with 71 distal radius fractures. After on average 26 months 58 patients with 59 fractures were clinically and radiologically evaluated. The patients were asked to give supplementary information about their follow-up treatment as well as any remaining physical difficulties and limitations in the daily life. All x-rays of the broken radius were carefully analysed and compared with the opposite side. The final results were evaluated according to the "Demerit Point System". Patients were treated with five different therapeutical methods. 76.3% of the patients showed a very good/good final result. In 56.7% of the cases secondary fracture dislocation occurred; the dislocation-rate of fractures treated with percutaneous k-wires was 93.3%! A clear correlation between secondary displacement and final results was found. A main factor for an optimal outcome is the anatomic restoration of length and axis of the distal radius as well as of joint congruency, also moderate angular deformities are well tolerated. Our collective showed an unexpected high rate of secondary displacement, especially in the k-wire group. The reasons for this unsatisfactory event are manifold: too optimistic indication, insufficient follow-up examination in the first four to six weeks, inconsequent change to a more stable fixation method in case of a secondary dislocation. The results of this retrospective evaluation had a major impact on our concept of treatment. The dorso-radial double-plate technique combined with bone graft will be more used in the future especially in younger patients. The new standardised concept is the

Recent Developments in Ultra High Temperature Ceramics at NASA Ames

NASA Technical Reports Server (NTRS)

Johnson, Sylvia M.; Gasch, Matt; Lawson, John W.; Gusman, Michael I.; Stackpole, Margaret M.

2009-01-01

NASA Ames is pursuing a variety of approaches to modify and control the microstructure of UHTCs with the goal of improving fracture toughness, oxidation resistance and controlling thermal conductivity. The overall goal is to produce materials that can perform reliably as sharp leading edges or nose tips in hypersonic reentry vehicles. Processing approaches include the use of preceramic polymers as the SiC source (as opposed to powder techniques), the addition of third phases to control grain growth and oxidation, and the use of processing techniques to produce high purity materials. Both hot pressing and field assisted sintering have been used to make UHTCs. Characterization of the mechanical and thermal properties of these materials is ongoing, as is arcjet testing to evaluate performance under simulated reentry conditions. The preceramic polymer approach has generated a microstructure in which elongated SiC grains grow in the form of an in-situ composite. This microstructure has the advantage of improving fracture toughness while potentially improving oxidation resistance by reducing the amount and interconnectivity of SiC in the material. Addition of third phases, such as Ir, results in a very fine-grained microstructure, even in hot-pressed samples. The results of processing and compositional changes on microstructure and properties are reported, along with selected arcjet results.

Post-fracture care: do we need to educate patients rather than doctors? The PREVOST randomized controlled trial.

PubMed

Merle, B; Chapurlat, R; Vignot, E; Thomas, T; Haesebaert, J; Schott, A-M

2017-05-01

We conducted a multicenter, randomized controlled trial to evaluate the impact of a population-based patient-centered post-fracture care program with a dedicated case manager, PREVention of OSTeoporosis (PREVOST), on appropriate post-fracture osteoporosis management. We showed that, compared to usual care, BMD investigation post-fracture was significantly improved (+20%) by our intervention program. Our study aims to evaluate the impact of a population-based patient-centered post-fracture care program, PREVOST, on appropriate post-fracture care. Multicenter, randomized controlled trial enrolling 436 women aged 50 to 85 years and attending a French hospital, for a low-energy fracture of the wrist or humerus. Randomization was stratified by age, hospital department, and site of fracture. The intervention was performed by a trained case manager who interacted only with the patients, with repeated oral and written information about fragility fractures and osteoporosis management, and prompting them to visit their primary care physicians. Control group received usual care. The primary outcome was the initiation of an appropriate post-fracture care defined by Bone Mineral Density (BMD) and/or anti-osteoporotic treatment prescription at 6 months. At 6 months, 53% of women in intervention group initiated a post-fracture care versus 33% for usual care (adjOR 2.35, 95%CI [1.58-3.50], p < 0.001). Post-fracture care was more frequent after wrist than humerus fracture (adjOR 1.93, 95%CI [1.14-3.30], p = 0.015) and decreased with age (adjOR for 10 years increase 0.76, 95%CI [0.61-0.96], p = 0.02). The intervention resulted in BMD prescription in 50% of patients (adjOR 2.10, 95%CI [1.41-3.11], p < 0.001) and in BMD performance in 41% of patients (adjOR 2.12, 95%CI [1.40-3.20], p < 0.001) versus 33 and 25% for usual care, respectively. Having performed a BMD increased treatment prescription; however, only 46% of women with a low BMD requiring a treatment according to

Overview of NASA's Thermal Control System Development for Exploration Project

NASA Technical Reports Server (NTRS)

Stephan, Ryan A.

2010-01-01

NASA's Constellation Program includes the Orion, Altair, and Lunar Surface Systems project offices. The first two elements, Orion and Altair, are manned space vehicles while the third element is broader and includes several sub-elements including Rovers and a Lunar Habitat. The upcoming planned missions involving these systems and vehicles include several risks and design challenges. Due to the unique thermal environment, many of these risks and challenges are associated with the vehicles' thermal control system. NASA's Exploration Systems Mission Directorate (ESMD) includes the Exploration Technology Development Program (ETDP). ETDP consists of several technology development projects. The project chartered with mitigating the aforementioned risks and design challenges is the Thermal Control System Development for Exploration Project. The risks and design challenges are addressed through a rigorous technology development process that culminates with an integrated thermal control system test. The resulting hardware typically has a Technology Readiness Level (TRL) of six. This paper summarizes the development efforts being performed by the technology development project. The development efforts involve heat acquisition and heat rejection hardware including radiators, heat exchangers, and evaporators. The project has also been developing advanced phase change material heat sinks and performing assessments for thermal control system fluids.

NASA Glenn Research in Controls and Diagnostics for Intelligent Aerospace Propulsion Systems

NASA Technical Reports Server (NTRS)

Garg, Sanjay

2007-01-01

With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Branch (CDB) at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with other organizations within GRC and across NASA, the U.S. aerospace industry, and academia to develop advanced controls and health management technologies that will help meet these challenges through the concept of Intelligent Propulsion Systems. This presentation describes the current CDB activities in support of the NASA Aeronautics Research Mission, with an emphasis on activities under the Integrated Vehicle Health Management (IVHM) and Integrated Resilient Aircraft Control (IRAC) projects of the Aviation Safety Program. Under IVHM, CDB focus is on developing advanced techniques for monitoring the health of the aircraft engine gas path with a focus on reliable and early detection of sensor, actuator and engine component faults. Under IRAC, CDB focus is on developing adaptive engine control technologies which will increase the probability of survival of aircraft in the presence of damage to flight control surfaces or to one or more engines. The technology development plans are described as well as results from recent research accomplishments.

The NASA Lewis integrated propulsion and flight control simulator

NASA Technical Reports Server (NTRS)

Bright, Michelle M.; Simon, Donald L.

1991-01-01

A new flight simulation facility has been developed at NASA Lewis to allow integrated propulsion-control and flight-control algorithm development and evaluation in real time. As a preliminary check of the simulator facility and the correct integration of its components, the control design and physics models for an STOVL fighter aircraft model have been demonstrated, with their associated system integration and architecture, pilot vehicle interfaces, and display symbology. The results show that this fixed-based flight simulator can provide real-time feedback and display of both airframe and propulsion variables for validation of integrated systems and testing of control design methodologies and cockpit mechanizations.

Decentralized control experiments on NASA's flexible grid

NASA Technical Reports Server (NTRS)

Ozguner, U.; Yurkowich, S.; Martin, J., III; Al-Abbass, F.

1986-01-01

Methods arising from the area of decentralized control are emerging for analysis and control synthesis for large flexible structures. In this paper the control strategy involves a decentralized model reference adaptive approach using a variable structure control. Local models are formulated based on desired damping and response time in a model-following scheme for various modal configurations. Variable structure controllers are then designed employing co-located angular rate and position feedback. In this scheme local control forces the system to move on a local sliding mode in some local error space. An important feature of this approach is that the local subsystem is made insensitive to dynamical interactions with other subsystems once the sliding surface is reached. Experiments based on the above have been performed for NASA's flexible grid experimental apparatus. The grid is designed to admit appreciable low-frequency structural dynamics, and allows for implementation of distributed computing components, inertial sensors, and actuation devices. A finite-element analysis of the grid provides the model for control system design and simulation; results of several simulations are reported on here, and a discussion of application experiments on the apparatus is presented.

An overview of integrated flight-propulsion controls flight research on the NASA F-15 research airplane

NASA Technical Reports Server (NTRS)

Burcham, Frank W., Jr.; Gatlin, Donald H.; Stewart, James F.

1995-01-01

The NASA Dryden Flight Research Center has been conducting integrated flight-propulsion control flight research using the NASA F-15 airplane for the past 12 years. The research began with the digital electronic engine control (DEEC) project, followed by the F100 Engine Model Derivative (EMD). HIDEC (Highly Integrated Digital Electronic Control) became the umbrella name for a series of experiments including: the Advanced Digital Engine Controls System (ADECS), a twin jet acoustics flight experiment, self-repairing flight control system (SRFCS), performance-seeking control (PSC), and propulsion controlled aircraft (PCA). The upcoming F-15 project is ACTIVE (Advanced Control Technology for Integrated Vehicles). This paper provides a brief summary of these activities and provides background for the PCA and PSC papers, and includes a bibliography of all papers and reports from the NASA F-15 project.

How NASA KSC Controls Interfaces with the use of Motion Skeletons and Product Structure

NASA Technical Reports Server (NTRS)

Jones, Corey

2013-01-01

This presentation will show how NASA KSC controls interfaces for Modular Product Architecture (MPA) using Locator Skeletons, Interface Skeletons, and Product Structure, to be combined together within a Motion Skeleton. The user will learn how to utilize skeleton models to communicate interface data, as successfully done at NASA KSC in their use of Motion Skeletons to control interfaces for multi-launch systems. There will be discussion of the methodology used to control design requirements through WTParts, and how to utilize product structure for non-CAD documents.

The Risk of Fractures Associated with Thiazolidinediones: A Self-controlled Case-Series Study

PubMed Central

Douglas, Ian J.; Evans, Stephen J.; Pocock, Stuart; Smeeth, Liam

2009-01-01

Background The results of clinical trials have suggested that the thiazolidinedione antidiabetic agents rosiglitazone and pioglitazone are associated with an increased risk of fractures, but such studies had limited power. The increased risk in these trials appeared to be limited to women and mainly involved fractures of the arm, wrist, hand, or foot: risk patterns that could not be readily explained. Our objective was to further investigate the risk of fracture associated with thiazolidinedione use. Methods and Findings The self-controlled case-series design was used to compare rates of fracture during thiazolidinedione exposed and unexposed periods and thus estimate within-person rate ratios. We used anonymised primary care data from the United Kingdom General Practice Research Database (GPRD). All patients aged 40 y or older with a recorded fracture and at least one prescription for a thiazolidinedione were included (n = 1,819). We found a within-person rate ratio of 1.43 (95% confidence interval [CI] 1.25–1.62) for fracture at any site comparing exposed with unexposed periods among patients prescribed any thiazolidinedione. This association was similar in men and women and in patients treated with either rosiglitazone or pioglitazone. The increased risk was also evident at a range of fracture sites, including hip, spine, arm, foot, wrist, or hand. The risk increased with increasing duration of thiazolidinedione exposure: rate ratio 2.00 (95% CI 1.48–2.70) for 4 y or more of exposure. Conclusion Within individuals who experience a fracture, fracture risk is increased during periods of exposure to thiazolidinediones (both rosiglitazone and pioglitazone) compared with unexposed periods. The increased risk is observed in both men and women and at a range of fracture sites. The risk also increases with longer duration of use. Please see later in the article for the Editors' Summary PMID:19787025

A prospective, controlled clinical evaluation of surgical stabilization of severe rib fractures.

PubMed

Pieracci, Fredric M; Lin, Yihan; Rodil, Maria; Synder, Madelyne; Herbert, Benoit; Tran, Dong Kha; Stoval, Robert T; Johnson, Jeffrey L; Biffl, Walter L; Barnett, Carlton C; Cothren-Burlew, Clay; Fox, Charles; Jurkovich, Gregory J; Moore, Ernest E

2016-02-01

Previous studies of surgical stabilization of rib fractures (SSRF) have been limited by small sample sizes, retrospective methodology, and inclusion of only patients with flail chest. We performed a prospective, controlled evaluation of SSRF as compared with optimal medical management for severe rib fracture patterns among critically ill trauma patients. We hypothesized that SSRF improves acute outcomes. We conducted a 2-year clinical evaluation of patients with any of the following rib fracture patterns: flail chest, three or more fractures with bicortical displacement, 30% or greater hemithorax volume loss, and either severe pain or respiratory failure despite optimal medical management. In the year 2013, all patients were managed nonoperatively. In the year 2014, all patients were managed operatively. Outcomes included respiratory failure, tracheostomy, pneumonia, ventilator days, tracheostomy, length of stay, daily maximum incentive spirometer volume, narcotic requirements, and mortality. Univariate and multivariable analyses were performed. Seventy patients were included, 35 in each group. For the operative group, time from injury to surgery was 2.4 day, operative time was 1.5 hours, and the ratio of ribs fixed to ribs fractured was 0.6. The operative group had a significantly higher RibScore (4 vs. 3, respectively, p < 0.01) and a significantly lower incidence of intracranial hemorrhage (5.7% vs. 28.6%, respectively, p = 0.01). After controlling for these differences, the operative group had a significantly lower likelihood of both respiratory failure (odds ratio, 0.24; 95% confidence interval, 0.06-0.93; p = 0.03) and tracheostomy (odds ratio, 0.18; 95% confidence interval, 0.04-0.78; p = 0.03). Duration of ventilation was significantly lower in the operative group (p < 0.01). The median daily spirometry value was 250 mL higher in the operative group (p = 0.04). Narcotic requirements were comparable between groups. There were no mortalities. In this

Mental workload measurement in operator control room using NASA-TLX

NASA Astrophysics Data System (ADS)

Sugarindra, M.; Suryoputro, M. R.; Permana, A. I.

2017-12-01

The workload, encountered a combination of physical workload and mental workload, is a consequence of the activities for workers. Central control room is one department in the oil processing company, employees tasked with monitoring the processing unit for 24 hours nonstop with a combination of 3 shifts in 8 hours. NASA-TLX (NASA Task Load Index) is one of the subjective mental workload measurement using six factors, namely the Mental demand (MD), Physical demand (PD), Temporal demand (TD), Performance (OP), Effort (EF), frustration levels (FR). Measurement of a subjective mental workload most widely used because it has a high degree of validity. Based on the calculation of the mental workload, there at 5 units (DTU, NPU, HTU, DIST and OPS) at the control chamber (94; 83.33; 94.67; 81, 33 and 94.67 respectively) that categorize as very high mental workload. The high level of mental workload on the operator in the Central Control Room is a requirement to have high accuracy, alertness and can make decisions quickly

Comparison of Wiltse's paraspinal approach and open book laminectomy for thoracolumbar burst fractures with greenstick lamina fractures: a randomized controlled trial.

PubMed

Chen, Zhi-da; Wu, Jin; Yao, Xiao-Tao; Cai, Tao-Yi; Zeng, Wen-Rong; Lin, Bin

2018-03-02

Posterior short-segment pedicle screw fixation is used to treat thoracolumbar burst fractures. However, no randomized controlled studies have compared the efficacy of the two approaches--the Wiltse's paraspinal approach and open book laminectomy in the treatment of thoracolumbar burst fractures with greenstick lamina fractures. Patients with burst fractures of the thoracolumbar spine without neurological deficit were randomized to receive either the Wiltse's paraspinal approach (group A, 24 patients) or open book laminectomy (group B, 23 patients). Patients were followed postoperatively for average of 27.4 months. Clinical and radiographic data of the two approaches were collected and compared. Our results showed the anterior segmental height, kyphotic angle, visual analog scale (VAS) score, and Smiley-Webster Scale (SWS) score significantly improved postoperatively in both groups, indicating that both the Wiltse's paraspinal approach and open book laminectomy can effectively treat thoracolumbar burst fractures with greenstick lamina fractures. The Wiltse's paraspinal approach was found to have significantly shorter operating time, less blood loss, and shorter length of hospital stay compared to open book laminectomy. However, there were two (2/24) patients in group A that had neurological deficits postoperatively and required a second exploratory operation. Dural tears and/or cauda equina entrapment were subsequently found in four patients in group B and all two patients of neurological deficits in group A during operation. No screw loosening, plate breakage, or other internal fixation failures were found at final follow-up. The results demonstrated that either of the two surgical approaches can achieve satisfactory results in treating thoracolumbar burst fractures in patients with greenstick lamina fractures. However, if there is any clinical or radiographic suspicion of a dural tear and/or cauda equina entrapment pre-operation, patients should receive an open

Global Hawk, NASA's New Remote-Controlled Plane

NASA Image and Video Library

2017-12-08

NASA image acquired October 23, 2009. At NASA’s Dryden Research Center in California, a group of engineers, scientists, and aviation technicians have set up camp in a noisy, chilly hangar on Edwards Air Force base. For the past two weeks, they have been working to mount equipment—from HD video cameras to ozone sensors—onto NASA’s Global Hawk, a remote-controlled airplane that can fly for up to 30 hours at altitudes up to 65,000 feet. The team is gearing up for the Global Hawk Pacific campaign, a series of four or five scientific research flights that will take the Global Hawk over the Pacific Ocean and Arctic regions. The 44-foot-long aircraft, with its comically large nose and 116-foot wingspan is pictured in the photograph above, banking for landing over Rogers Dry Lake in California at the end of a test flight on October 23, 2009. The long wings carry the plane’s fuel, and the bulbous nose is one of the payload bays, which house the science instruments. For the Global Hawk Pacific campaign, the robotic aircraft will carry ten science instruments that will sample the chemical composition of air in the troposphere (the atmospheric layer closest to Earth) and the stratosphere (the layer above the troposphere). The mission will also observe clouds and aerosol particles in the troposphere. The primary purpose of the mission is to collect observations that can be used to check the accuracy of simultaneous observations collected by NASA’s Aura satellite. Co-lead scientist Paul Newman from Goddard Space Flight Center is writing about the ground-breaking mission for the Earth Observatory’s Notes from the Field blog. NASA Photograph by Carla Thomas. NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. To learn more about this image go to: earthobservatory.nasa

Intensive glycemic control is not associated with fractures or falls in the ACCORD randomized trial.

PubMed

Schwartz, Ann V; Margolis, Karen L; Sellmeyer, Deborah E; Vittinghoff, Eric; Ambrosius, Walter T; Bonds, Denise E; Josse, Robert G; Schnall, Adrian M; Simmons, Debra L; Hue, Trisha F; Palermo, Lisa; Hamilton, Bruce P; Green, Jennifer B; Atkinson, Hal H; O'Connor, Patrick J; Force, Rex W; Bauer, Douglas C

2012-07-01

Older adults with type 2 diabetes are at high risk of fractures and falls, but the effect of glycemic control on these outcomes is unknown. To determine the effect of intensive versus standard glycemic control, we assessed fractures and falls as outcomes in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) randomized trial. ACCORD participants were randomized to intensive or standard glycemia strategies, with an achieved median A1C of 6.4 and 7.5%, respectively. In the ACCORD BONE ancillary study, fractures were assessed at 54 of the 77 ACCORD clinical sites that included 7,287 of the 10,251 ACCORD participants. At annual visits, 6,782 participants were asked about falls in the previous year. During an average follow-up of 3.8 (SD 1.3) years, 198 of 3,655 participants in the intensive glycemia and 189 of 3,632 participants in the standard glycemia group experienced at least one nonspine fracture. The average rate of first nonspine fracture was 13.9 and 13.3 per 1,000 person-years in the intensive and standard groups, respectively (hazard ratio 1.04 [95% CI 0.86-1.27]). During an average follow-up of 2.0 years, 1,122 of 3,364 intensive- and 1,133 of 3,418 standard-therapy participants reported at least one fall. The average rate of falls was 60.8 and 55.3 per 100 person-years in the intensive and standard glycemia groups, respectively (1.10 [0.84-1.43]). Compared with standard glycemia, intensive glycemia did not increase or decrease fracture or fall risk in ACCORD.

Hydro-fracture in the laboratory: matching diagnostic seismic signals to fracture networks

NASA Astrophysics Data System (ADS)

Gehne, S.; Benson, P. M.; Koor, N.; Dobson, K. J.; Enfield, M.; Barber, A.

2017-12-01

Hydraulic fracturing is a key process in both natural (e.g. dyke intrusion) and engineered environments (e.g. shale gas). To better understand this process, we present new data from simulated hydraulic fracturing in a controlled laboratory environment in order to track fracture nucleation (location) and propagation (velocity) in space and time to assess the fracture mechanics and developing fracture network. Fluid overpressure is used to generate a permeable network of micro tensile fractures in an anisotropic sandstone and a highly anisotropic shale. A newly developed technique, using a steel guide arrangement to direct pressurised fluid into a sealed section of an axially drilled conduit, allows the pore fluid to contact the rock directly and to initiate tensile fractures from a pre-defined zone inside the sample. Acoustic emission location is used to record and map the nucleation and development of the micro-fracture network. For both rock types, fractures progresses parallel to the bedding plane (short-transverse) if the bedding plane is aligned with the direction of σ1 requiring breakdown pressures of approximately 7 and 13MPa respectively at a confining pressure of 8MPa. The data also indicates a more ductile behaviour of the shale than expected. We use X-Ray Computed Tomography (CT) to evaluate the evolved fracture network in terms of fracture pattern and aperture. Hydraulic fracturing produces very planar fractures in the shale, with axial fractures over the entire length of the sample broadly following the bedding. In contrast, fractures in the sandstone are more diffuse, linking pore spaces as they propagate. However, secondary micro cracking, branching of the main fracture, are also observed. These new experiments suggest that fracture pattern, fracture propagation trajectories, and fracturing fluid pressures are predominantly controlled by the interaction between the anisotropic mechanical properties of the rock and the anisotropic stress environment.

[Application of damage control concept in severe limbs fractures combining with multiple trauma].

PubMed

Bayin, Er-gu-le; Jin, Hong-bing; Li, Ming

2015-09-01

To discuss the application and clinical effect of damage control concept in the treatment of severe limbs fractures combining with multiple trauma. From July 2009 to July 2012, 30 patients with severe limbs fractures combining with multiple trauma were treated with the damage control concept, included 20 males and 10 females with an average age of (34.03 ± 12.81) years old ranging from 20 to 60 years old; the ISS averaged (35.00 ± 12.81) points (ranged from 26 to 54 points). And the control group also contained 30 patients with severe limbs fractures combining with multiple trauma treated by the traditional operation from June 2006 to June 2009, there were 23 males and 7 females with an average age of (34.23 ± 11.04) years old ranging from 18 to 65 years old. The ISS averaged (35.56 ± 11.04) points (ranged from 26 to 51 points). The age, gender, ISS, Gustilo classification, operation time, intraoperative blood loss, blood transfusion,postoperative complications and mortality rate were observed and compared. In the damage control concept group,there were 28 cases surviving and 2 cases (6.7%) death; 6 cases of postoperative complication included 2 cases of adult respiratory distress syndrome, 1 case of multiple organ failure, 1 case of disseminated intravascular coagulation and 2 cases of wound infection. In the control group, there were 22 cases surviving and 8 cases death(26.7%); 13 cases of postoperative complication included 4 cases of adult respiratory distress syndrome,2 cases of multiple organ failure, 2 cases of disseminated intravascular coagulation and 3 cases of wound infection. There were no statistically significant differences between two groups in age, gender, ISS, Gustilo classfication and complication (P > 0.05), however there were statistically significant differences in mortality rate, operation time, blodd loss, blodd transfusion between two groups (P < 0.05). Damage control concept is used to treat severe limbs fractures combining with

Mirror therapy for distal radial fractures: A pilot randomized controlled study.

PubMed

Bayon-Calatayud, Manuel; Benavente-Valdepeñas, Ana Maria; Del Prado Vazquez-Muñoz, Maria

2016-10-12

To investigate the efficacy of mirror therapy in reducing pain and disability in patients with distal radial fractures. Pilot randomized controlled study. Twenty-two patients with closed distal radial fracture. Patients were randomly assigned to experimental (= 11) or control (= 11) groups. Researchers were blinded to group allocation. Both groups received conventional physiotherapy. In addition, the experimental group had 15 sessions of mirror therapy (a daily session, 30 min). The control group received the same amount of conventional occupational therapy. Assessment was made from baseline to post-treatment. Pain was measured on a visual analogue scale (VAS). Active wrist extension and Quick-DASH (Disabilities of Arm, Shoulder and Hand) were used to assess functional recovery. Pain, disability, and range of motion improved for both groups after intervention. No significant post-treatment differences were found between groups in Quick-DASH (= 0.409), active wrist extension (= 0.191) and VAS scores (= 0.807). There was no significant difference in active wrist extension between groups. Mirror therapy was not superior to conventional occupational therapy in reducing pain and disability.

Replacement/Refurbishment of JSC/NASA POD Specimens

NASA Technical Reports Server (NTRS)

Castner, Willard L.

2010-01-01

The NASA Special NDE certification process requires demonstration of NDE capability by test per NASA-STD-5009. This test is performed with fatigue cracked specimens containing very small cracks. The certification test results are usually based on binomial statistics and must meet a 90/95 Probability of Detection (POD). The assumption is that fatigue cracks are tightly closed, difficult to detect, and inspectors and processes passing such a test are well qualified for inspecting NASA fracture critical hardware. The JSC NDE laboratory has what may be the largest inventory that exists of such fatigue cracked NDE demonstration specimens. These specimens were produced by the hundreds in the late 1980s and early 1990s. None have been produced since that time and the condition and usability of the specimens are questionable.

Acoustic Monitoring of Gravity-Driven Controls on CaCO3 Precipitates in a Fracture

NASA Astrophysics Data System (ADS)

Xu, Z.; Sheets, J.; Zhang, L.; Kim, D.; Kneafsey, T. J.; Cole, D. R.; Jun, Y. S.; Pyrak-Nolte, L. J.

2017-12-01

the orientation thus affecting the ability of a fracture to self-heal if oriented vertically. This work was supported by the Center for Nanoscale Controls on Geologic CO (NCGC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-AC02-05CH11231

Physiotherapy Rehabilitation for Osteoporotic Vertebral Fracture (PROVE): study protocol for a randomised controlled trial

PubMed Central

2014-01-01

Background Osteoporosis and vertebral fracture can have a considerable impact on an individual’s quality of life. There is increasing evidence that physiotherapy including manual techniques and exercise interventions may have an important treatment role. This pragmatic randomised controlled trial will investigate the clinical and cost-effectiveness of two different physiotherapy approaches for people with osteoporosis and vertebral fracture, in comparison to usual care. Methods/Design Six hundred people with osteoporosis and a clinically diagnosed vertebral fracture will be recruited and randomly allocated to one of three management strategies, usual care (control - A), an exercise-based physiotherapy intervention (B) or a manual therapy-based physiotherapy intervention (C). Those in the usual care arm will receive a single session of education and advice, those in the active treatment arms (B + C) will be offered seven individual physiotherapy sessions over 12 weeks. The trial is designed as a prospective, adaptive single-blinded randomised controlled trial. An interim analysis will be completed and if one intervention is clearly superior the trial will be adapted at this point to continue with just one intervention and the control. The primary outcomes are quality of life measured by the disease specific QUALLEFO 41 and the Timed Loaded Standing test measured at 1 year. Discussion There are a variety of different physiotherapy packages used to treat patients with osteoporotic vertebral fracture. At present, the indication for each different therapy is not well defined, and the effectiveness of different modalities is unknown. Trial registration Reference number ISRCTN49117867. PMID:24422876

Extensive Ice Fractures in the Beaufort Sea [detail

NASA Image and Video Library

2017-12-08

much heat the surface was emitting as VIIRS surveyed the area. Cooler areas (sea ice) appear white, while warmer areas (open water) are dark. The light gray plume near the cracks is warmer, moister air escaping from the ocean and blowing downwind. Clouds do not show up well in the VIIRS thermal band, so the storms that fueled the fracturing are not readily visible. While fracturing events are common, few events sprawl across such a large area or produce cracks as long and wide as those seen here. The age of the sea ice in this area was one of the key reasons this event became so widespread. “The region is covered almost completely by seasonal or first-year ice—ice that has formed since last September,” said Meier. “This ice is thinner and weaker than the older, multi-year ice, so it responds more readily to winds and is more easily broken up.” NASA Earth Observatory images by Jesse Allen using VIIRS day-night band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Adam Voiland. Instrument: Suomi NPP - VIIRS For more info go to: earthobservatory.nasa.gov/IOTD/view.php?id=80752 Credit: NASA Earth Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Extensive Ice Fractures in the Beaufort Sea [annotated

NASA Image and Video Library

2017-12-08

much heat the surface was emitting as VIIRS surveyed the area. Cooler areas (sea ice) appear white, while warmer areas (open water) are dark. The light gray plume near the cracks is warmer, moister air escaping from the ocean and blowing downwind. Clouds do not show up well in the VIIRS thermal band, so the storms that fueled the fracturing are not readily visible. While fracturing events are common, few events sprawl across such a large area or produce cracks as long and wide as those seen here. The age of the sea ice in this area was one of the key reasons this event became so widespread. “The region is covered almost completely by seasonal or first-year ice—ice that has formed since last September,” said Meier. “This ice is thinner and weaker than the older, multi-year ice, so it responds more readily to winds and is more easily broken up.” NASA Earth Observatory images by Jesse Allen using VIIRS day-night band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Adam Voiland. Instrument: Suomi NPP - VIIRS For more info go to: earthobservatory.nasa.gov/IOTD/view.php?id=80752 Credit: NASA Earth Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Use of a case manager to improve osteoporosis treatment after hip fracture: results of a randomized controlled trial.

PubMed

Majumdar, Sumit R; Beaupre, Lauren A; Harley, Charles H; Hanley, David A; Lier, Douglas A; Juby, Angela G; Maksymowych, Walter P; Cinats, John G; Bell, Neil R; Morrish, Donald W

2007-10-22

Patients who survive hip fracture are at high risk of recurrent fractures, but rates of osteoporosis treatment 1 year after sustaining a fracture are less than 10% to 20%. We have developed an osteoporosis case manager intervention. The case manager educated patients, arranged bone mineral density tests, provided prescriptions, and communicated with primary care physicians. The intervention was compared with usual care in a randomized controlled trial. We recruited from all hospitals that participate in the Capital Health system (Alberta, Canada), including patients 50 years or older who had sustained a hip fracture and excluding those who were receiving osteoporosis treatment or who lived in a long-term care facility. Primary outcome was bisphosphonate therapy 6 months after fracture; secondary outcomes included bone mineral density testing, appropriate care (bone mineral density testing and treatment if bone mass was low), and intervention costs. We screened 2219 patients and allocated 220, as follows: 110 to the intervention group and 110 to the control group. Median age was 74 years, 60% were women, and 37% reported having had previous fractures. Six months after hip fracture, 56 patients in the intervention group (51%) were receiving bisphosphonate therapy compared with 24 patients in the control group (22%) (adjusted odds ratio, 4.7; 95% confidence interval, 2.4-8.9; P < .001). Bone mineral density tests were performed in 88 patients in the intervention group (80%) vs 32 patients in the control group (29%) (P < .001). Of the 120 patients who underwent bone mineral density testing, 25 (21%) had normal bone mass. Patients in the intervention group were more likely to receive appropriate care than were patients in the control group (67% vs 26%; P < .001). The average intervention cost was $50.00 per patient. For a modest cost, a case manager was able to substantially increase rates of osteoporosis treatment in a vulnerable elderly population at high risk of

Control of NASA's Space Launch System

NASA Technical Reports Server (NTRS)

VanZwieten, Tannen S.

2014-01-01

The flight control system for the NASA Space Launch System (SLS) employs a control architecture that evolved from Saturn, Shuttle & Ares I-X while also incorporating modern enhancements. This control system, baselined for the first unmanned launch, has been verified and successfully flight-tested on the Ares I-X rocket and an F/A-18 aircraft. The development of the launch vehicle itself came on the heels of the Space Shuttle retirement in 2011, and will deliver more payload to orbit and produce more thrust than any other vehicle, past or present, opening the way to new frontiers of space exploration as it carries the Orion crew vehicle, equipment, and experiments into new territories. The initial 70 metric ton vehicle consists of four RS-25 core stage engines from the Space Shuttle inventory, two 5- segment solid rocket boosters which are advanced versions of the Space Shuttle boosters, and a core stage that resembles the External Tank and carries the liquid propellant while also serving as the vehicle's structural backbone. Just above SLS' core stage is the Interim Cryogenic Propulsion Stage (ICPS), based upon the payload motor used by the Delta IV Evolved Expendable Launch Vehicle (EELV).

NASA's Contributions to Controlled Environment Agriculture

NASA Technical Reports Server (NTRS)

Wheeler, Raymond M.

2016-01-01

It may come as a surprise, but NASA has been a long-standing sponsor of controlled environment agriculture (CEA) research. This is based on the potential for using plants (crops) for life support systems in space. Through photosynthesis, crops could produce food and oxygen for humans, while removing CO2. In addition, plant transpiration could help purify waste water. NASAs interest in bioregenerative life support dates back to the late 1950s. At that time, much of the testing focused on algae, but over the years moved toward higher plants as CEA techniques improved. Throughout the 1980s and 90s, extensive testing was carried out at different universities to gather horticultural data for a range of crops, including wheat, soybean, lettuce, potato, sweet potato, cowpea, rice and more. These studies examined different electric light sources, mineral nutrition, recirculating hydroponics, effects of CO2, temperature, photosynthetic photon flux (PPF), and photoperiod on the crops, and identified cultivars that would be useful for space. Findings from these studies were then used to conduct large scale (20 sq m), closed atmosphere tests at Kennedy Space Center, and later at NASA Johnson Space Center, where plant growth chambers were linked to human habitats. Results showed that with high light input and careful horticultural management, about 20-25 sq m of crops under continuous cultivation could produce the O2 for one person, and about 40-50 sq m could produce enough dietary calories. The ability to sustain these production levels and accurately assess system costs and failures needs further study. In all likelihood, the use of plants for life support will evolve, where for early missions like the International Space Station, crops will be grown in small chambers to provide supplemental fresh foods. As mission durations and distances increase, the systems could expand to assume more of the life support burden. But the constraints of space travel require that these

NASA B737 flight test results of the total energy control system

NASA Technical Reports Server (NTRS)

Bruce, Kevin R.

1987-01-01

The Total Energy Control System (TECS) is an integrated autopilot/autothrottle developed by BCAC that was test flown on NASA Langley's Transport System Research Vehicle (i.e., a highly modified Boeing B737). This systems was developed using principles of total energy in which the total kinetic and potential energy of the airplane was controlled by the throttles, and the energy distribution controled by the elevator. TECS integrates all the control functions of a conventional pitch autopilot and autothrottle into a single generalized control concept. This integration provides decoupled flightpath and maneuver control, as well as a coordinated throttle response for all maneuvers. A mode hierarchy was established to preclude exceeding airplane safety and performance limits. The flight test of TECS took place as a series of five flights over a 33-week period during September 1985 at NASA Langley. Most of the original flight test plan was completed within the first three flights with the system not exhibiting any instabilities or design problems that required any gain adjustment during flight.

Elastic plastic fracture mechanics methodology for surface cracks

NASA Technical Reports Server (NTRS)

Ernst, Hugo A.; Lambert, D. M.

1994-01-01

The Elastic Plastic Fracture Mechanics Methodology has evolved significantly in the last several years. Nevertheless, some of these concepts need to be extended further before the whole methodology can be safely applied to structural parts. Specifically, there is a need to include the effect of constraint in the characterization of material resistance to crack growth and also to extend these methods to the case of 3D defects. As a consequence, this project was started as a 36 month research program with the general objective of developing an elastic plastic fracture mechanics methodology to assess the structural reliability of pressure vessels and other parts of interest to NASA which may contain flaws. The project is divided into three tasks that deal with (1) constraint and thickness effects, (2) three-dimensional cracks, and (3) the Leak-Before-Burst (LBB) criterion. This report period (March 1994 to August 1994) is a continuation of attempts to characterize three dimensional aspects of fracture present in 'two dimensional' or planar configuration specimens (Chapter Two), especially, the determination of, and use of, crack face separation data. Also, included, are a variety of fracture resistance testing results (J(m)R-curve format) and a discussion regarding two materials of NASA interest (6061-T651 Aluminum alloy and 1N718-STA1 nickel-base super alloy) involving a bases for like constraint in terms of ligament dimensions, and their comparison to the resulting J(m)R-curves (Chapter Two).

NASA F-16XL supersonic laminar flow control program overview

NASA Technical Reports Server (NTRS)

Fischer, Michael C.

1992-01-01

The viewgraphs and discussion of the NASA supersonic laminar flow control program are provided. Successful application of laminar flow control to a High Speed Civil Transport (HSCT) offers significant benefits in reductions of take-off gross weight, mission fuel burn, cruise drag, structural temperatures, engine size, emissions, and sonic boom. The ultimate economic success of the proposed HSCT may depend on the successful adaption of laminar flow control, which offers the single most significant potential improvements in lift drag ratio (L/D) of all the aerodynamic technologies under consideration. The F-16XL Supersonic Laminar Flow Control (SLFC) Experiment was conceived based on the encouraging results of in-house and NASA supported industry studies to determine if laminar flow control is feasible for the HSCT. The primary objective is to achieve extensive laminar flow (50-60 percent chord) on a highly swept supersonic wing. Data obtained from the flight test will be used to validate existing Euler and Navier Stokes aerodynamic codes and transition prediction boundary layer stability codes. These validated codes and developed design methodology will be delivered to industry for their use in designing supersonic laminar flow control wings. Results from this experiment will establish preliminary suction system design criteria enabling industry to better size the suction system and develop improved estimates of system weight, fuel volume loss due to wing ducting, turbocompressor power requirements, etc. so that benefits and penalties can be more accurately assessed.

NASA - Beyond Boundaries

NASA Technical Reports Server (NTRS)

McMillan, Courtenay

2016-01-01

NASA is able to achieve human spaceflight goals in partnership with international and commercial teams by establishing common goals and building connections. Presentation includes photographs from NASA missions - on orbit, in Mission Control, and at other NASA facilities.

Contrasting Perspectives Of Junior versus Senior NASA ISS Flight Controllers On Leadership And Cultural Issues

NASA Technical Reports Server (NTRS)

Clement, James L.; Boyd, J. E.; Saylor, S.; Kanas, N.

2007-01-01

NASA flight controllers have always worked in a very demanding environment, but the International Space Station (ISS) poses even more challenges than prior missions. A recent NASA/Ames survey by Parke and Orasanu of NASA/Johnson flight controllers uncovered concerns about communications problems between American personnel and their international counterparts. To better understand these problems, we interviewed 14 senior and 12 junior ISS flight controllers at NASA/Johnson about leadership and cultural challenges they face and strategies for addressing these challenges. The qualitative interview data were coded and tabulated. Here we present quantitative analyses testing for differences between junior and senior controllers. Based on nonparametric statistical tests comparing responses across groups, the senior controllers were significantly more aware of the impact of working in dispersed teams, the context of constant change, and the upcoming multilateral challenges, while junior controllers were more aware of language and cultural issues. We consider our findings in light of other studies of controllers and other known differences between senior and junior controllers. For example, the fact that senior controllers had their formative early experience controlling pre-ISS short-duration Shuttle missions seems to have both positive and negative aspects, which are supported by our data. Our findings may also reflect gender differences, but we cannot unconfound this effect in our data because all the senior respondents were males. Many of the junior-senior differences are not only due to elapsed time on the job, but also due to a cohort effect. The findings of this study should be used for training curricula tailored differently for junior and senior controllers.

NASA supercritical laminar flow control airfoil experiment

NASA Technical Reports Server (NTRS)

Harvey, W. D.

1982-01-01

The design and goals of experimental investigations of supercritical LFC airfoils conducted in the NASA Langley 8-ft Transonic Pressure Tunnel beginning in March 1982 are reviewed. Topics addressed include laminarization aspects; flow-quality requirements; simulation of flight parameters; the setup of screens, honeycomb, and sonic throat; the design cycle; theoretical pressure distributions and shock-free limits; drag divergence and stability analysis; and the LFC suction system. Consideration is given to the LFC airfoil model, the air-flow control system, airfoil-surface instrumentation, liner design and hardware, and test options. Extensive diagrams, drawings, graphs, photographs, and tables of numerical data are provided.

Flight Research into Simple Adaptive Control on the NASA FAST Aircraft

NASA Technical Reports Server (NTRS)

Hanson, Curtis E.

2011-01-01

A series of simple adaptive controllers with varying levels of complexity were designed, implemented and flight tested on the NASA Full-Scale Advanced Systems Testbed (FAST) aircraft. Lessons learned from the development and flight testing are presented.

NASA personnel in a control room during the successful second flight of the X-43A aircraft

NASA Image and Video Library

2004-03-27

NASA personnel in a control room during the successful second flight of the X-43A aircraft. front row, left to right: Randy Voland, LaRC Propulsion; Craig Christy, Boeing Systems; Dave Reubush, NASA Hyper-X Deputy Program Manager; and Vince Rausch, NASA Hyper-X Program Manager. back row, left to right: Bill Talley, DCI/consultant; Pat Stoliker, DFRC Director (Acting) of Research Engineering; John Martin, LaRC G&C; and Dave Bose, AMA/Controls.

Fractures in Carbonate-Bearing Rocks at Mars Huygens Basin

NASA Image and Video Library

2011-03-08

This false-color image NASA Mars Reconnaissance Orbiter shows that fractures and possible layers are visible in the light-toned rock exposure containing the carbonates. The location is inside an unnamed crater on the uplifted rim of Huygens crater.

Cemented Fractures in Mountain Inside Gale Crater on Mars

NASA Image and Video Library

2011-07-22

One type of feature of scientific interest on the mountain inside Gale crater is exposure of cemented fractures, evidence that groundwater once reached to at least that height of the mountain. This image is from NASA Mars Reconnaissance Orbiter.

Recent advances in active noise and vibration control at NASA Langley Research Center

NASA Astrophysics Data System (ADS)

Gibbs, Gary P.; Cabell, Randolph H.; Palumbo, Daniel L.; Silcox, Richard J.; Turner, Travis L.

2002-11-01

Over the past 15 years NASA has investigated the use of active control technology for aircraft interior noise. More recently this work has been supported through the Advanced Subsonic Technology Noise Reduction Program (1994-2001), High Speed Research Program (1994-1999), and through the Quiet Aircraft Technology Program (2000-present). The interior environment is recognized as an important element in flight safety, crew communications and fatigue, as well as passenger comfort. This presentation will overview research in active noise and vibration control relating to interior noise being investigated by NASA. The research to be presented includes: active control of aircraft fuselage sidewall transmission due to turbulent boundary layer or jet noise excitation, active control of interior tones due to propeller excitation of aircraft structures, and adaptive stiffening of structures for noise, vibration, and fatigue control. Work on actuator technology ranging from piezoelectrics, shape memory actuators, and fluidic actuators will be described including applications. Control system technology will be included that is experimentally based, real-time, and adaptive.

Risk factors for falls with severe fracture in elderly people living in a middle-income country: a case control study.

PubMed

Coutinho, Evandro S F; Fletcher, Astrid; Bloch, Katia V; Rodrigues, Laura C

2008-08-26

Fracture after falling has been identified as an important problem in public health. Most studies of risk factors for fractures due to falls have been carried out in developed countries, although the size of the elderly population is increasing fast in middle income countries. The objective of this paper is to identify risk factors for fall related to severe fractures in those aged 60 or more in a middle-income country. A case-control study was carried out in Rio de Janeiro-Brazil based general hospitals between 2002-2003. Two hundred-fifty hospitalised cases of fracture were matched with 250 community controls by sex, age group and living area. Data were collected for socio-demographic variables, health status and drugs used before the fall. A conditional logistic regression model was fitted to identify variables associated with the risk of fall related severe fracture. Low body mass index, cognitive impairment, stroke and lack of urine control were associated with increased risk of severe fall related fractures. Benzodiazepines and muscle relaxants were also related to an increased risk of severe fractures while moderate use of alcohol was associated with reduced risk. Although the association between benzodiazepines and fractures due to fall has been consistently demonstrated for old people, this has not been the case for muscle relaxant drugs. The decision to prescribe muscle relaxants for elderly people should take into account the risk of severe fracture associated with these drugs.

Touchdown: The Development of Propulsion Controlled Aircraft at NASA Dryden

NASA Technical Reports Server (NTRS)

Tucker, Tom

1999-01-01

This monograph relates the important history of the Propulsion Controlled Aircraft project at NASA's Dryden Flight Research Center. Spurred by a number of airplane crashes caused by the loss of hydraulic flight controls, a NASA-industry team lead by Frank W. Burcham and C. Gordon Fullerton developed a way to land an aircraft safely using only engine thrust to control the airplane. In spite of initial skepticism, the team discovered that, by manually manipulating an airplane's thrust, there was adequate control for extended up-and-away flight. However, there was not adequate control precision for safe runway landings because of the small control forces, slow response, and difficulty in damping the airplane phugoid and Dutch roll oscillations. The team therefore conceived, developed, and tested the first computerized Propulsion Controlled Aircraft (PCA) system. The PCA system takes pilot commands, uses feedback from airplane measurements, and computes commands for the thrust of each engine, yielding much more precise control. Pitch rate and velocity feedback damp the phugoid oscillation, while yaw rate feedback damps the Dutch roll motion. The team tested the PCA system in simulators and conducted flight research in F-15 and MD-11 airplanes. Later, they developed less sophisticated variants of PCA called PCA Lite and PCA Ultralite to make the system cheaper and therefore more attractive to industry. This monograph tells the PCA story in a non- technical way with emphasis on the human aspects of the engineering and flic,ht-research effort. It thereby supplements the extensive technical literature on PCA and makes the development of this technology accessible to a wide audience.

Dynamic characterization and microprocessor control of the NASA/UVA proof mass actuator

NASA Technical Reports Server (NTRS)

Zimmerman, D. C.; Inman, D. J.; Horner, G. C.

1984-01-01

The self-contained electromagnetic-reaction-type force-actuator system developed by NASA/UVA for the verification of spacecraft-structure vibration-control laws is characterized and demonstrated. The device is controlled by a dedicated microprocessor and has dynamic characteristics determined by Fourier analysis. Test data on a cantilevered beam are shown.

NASA LaRC Workshop on Guidance, Navigation, Controls, and Dynamics for Atmospheric Flight, 1993

NASA Technical Reports Server (NTRS)

Buttrill, Carey S. (Editor)

1993-01-01

This publication is a collection of materials presented at a NASA workshop on guidance, navigation, controls, and dynamics (GNC&D) for atmospheric flight. The workshop was held at the NASA Langley Research Center on March 18-19, 1993. The workshop presentations describe the status of current research in the GNC&D area at Langley over a broad spectrum of research branches. The workshop was organized in eight sessions: overviews, general, controls, military aircraft, dynamics, guidance, systems, and a panel discussion. A highlight of the workshop was the panel discussion which addressed the following issue: 'Direction of guidance, navigation, and controls research to ensure U.S. competitiveness and leadership in aerospace technologies.'

NASA's Software Safety Standard

NASA Technical Reports Server (NTRS)

Ramsay, Christopher M.

2005-01-01

NASA (National Aeronautics and Space Administration) relies more and more on software to control, monitor, and verify its safety critical systems, facilities and operations. Since the 1960's there has hardly been a spacecraft (manned or unmanned) launched that did not have a computer on board that provided vital command and control services. Despite this growing dependence on software control and monitoring, there has been no consistent application of software safety practices and methodology to NASA's projects with safety critical software. Led by the NASA Headquarters Office of Safety and Mission Assurance, the NASA Software Safety Standard (STD-18l9.13B) has recently undergone a significant update in an attempt to provide that consistency. This paper will discuss the key features of the new NASA Software Safety Standard. It will start with a brief history of the use and development of software in safety critical applications at NASA. It will then give a brief overview of the NASA Software Working Group and the approach it took to revise the software engineering process across the Agency.

Hip fracture risk and cadmium in erythrocytes: a nested case-control study with prospectively collected samples.

PubMed

Sommar, Johan Nilsson; Pettersson-Kymmer, Ulrika; Lundh, Thomas; Svensson, Olle; Hallmans, Göran; Bergdahl, Ingvar A

2014-02-01

Several studies have investigated the relation between bone mass density and cadmium exposure, but only few studies have been performed on fractures and biomarkers of cadmium. This study analyzed the association between hip fracture risk and cadmium in erythrocytes (Ery-Cd). Prospective samples from the Northern Sweden Health and Disease Study's biobank were used for 109 individuals who later in life had sustained a low-trauma hip fracture, matched with two controls of the same age and gender. The mean concentration of Ery-Cd (±SD) in case samples was 1.3 ± 1.4 versus 0.9 ± 1.0 μg/L in controls. The odds ratio (OR) was 1.63 [95% confidence interval (CI) 1.10-2.42] for suffering a hip fracture for each microgram per liter increase in Ery-Cd. However, when taking smoking into consideration (never, former, or current), neither Ery-Cd nor smoking showed a statistically significant increase in fracture risk. Using multiple conditional logistic regression with BMI, height, and smoking, the estimated OR for a 1-μg/L increase in Ery-Cd was 1.52 (95% CI 0.77-2.97). Subgroup analysis showed an increased fracture risk among women (OR = 1.94, 95% CI 1.18-3.20, for a 1 μg/L increase), which also remained in the multiple analysis (OR = 3.33, 95% CI 1.29-8.56). This study shows that fracture risk is associated with Ery-Cd. It is, however, not possible to draw firm conclusions on whether cadmium is the causal factor or whether other smoking-related factors cause this association. Subgroup analysis shows that cadmium is a risk factor for hip fracture among women.

The NASA Lewis integrated propulsion and flight control simulator

NASA Technical Reports Server (NTRS)

Bright, Michelle M.; Simon, Donald L.

1991-01-01

A new flight simulation facility was developed at NASA-Lewis. The purpose of this flight simulator is to allow integrated propulsion control and flight control algorithm development and evaluation in real time. As a preliminary check of the simulator facility capabilities and correct integration of its components, the control design and physics models for a short take-off and vertical landing fighter aircraft model were shown, with their associated system integration and architecture, pilot vehicle interfaces, and display symbology. The initial testing and evaluation results show that this fixed based flight simulator can provide real time feedback and display of both airframe and propulsion variables for validation of integrated flight and propulsion control systems. Additionally, through the use of this flight simulator, various control design methodologies and cockpit mechanizations can be tested and evaluated in a real time environment.

Recent developments in analysis of crack propagation and fracture of practical materials

NASA Technical Reports Server (NTRS)

Hardrath, H. F.; Newman, J. C., Jr.; Elber, W.; Poe, C. C., Jr.

1978-01-01

Present U.S. Air Force and proposed U.S. civil airworthiness regulations are based on considerations of 'damage tolerance' in aircraft structures. Airworthiness is assured by demonstrating that damage that escapes one in a sequence of periodic inspections will not grow to critical size before the next inspection. The evaluations conducted employ fracture mechanics analyses. Problems arise because the features of fracture mechanics applications related to aircraft structures are more complex than the cases of fracture mechanics which have been mainly investigated. NASA has, therefore, conducted a variety of research tasks to extend the capabilities of fracture mechanics to deal with some of these complexities. The current stage of development of these capabilities is described. Attention is given to the limitations of linear elastic fracture mechanics, a two-parameter fracture criterion, aspects of fatigue crack propagation, and crack propagation and fracture in built-up structures.

Fundamental differences in axial and appendicular bone density in stress fractured and uninjured Royal Marine recruits--a matched case-control study.

PubMed

Davey, Trish; Lanham-New, Susan A; Shaw, Anneliese M; Cobley, Rosalyn; Allsopp, Adrian J; Hajjawi, Mark O R; Arnett, Timothy R; Taylor, Pat; Cooper, Cyrus; Fallowfield, Joanne L

2015-04-01

Stress fracture is a common overuse injury within military training, resulting in significant economic losses to the military worldwide. Studies to date have failed to fully identify the bone density and bone structural differences between stress fractured personnel and controls due to inadequate adjustment for key confounding factors; namely age, body size and physical fitness; and poor sample size. The aim of this study was to investigate bone differences between male Royal Marine recruits who suffered a stress fracture during the 32 weeks of training and uninjured control recruits, matched for age, body weight, height and aerobic fitness. A total of 1090 recruits were followed through training and 78 recruits suffered at least one stress fracture. Bone mineral density (BMD) was measured at the lumbar spine (LS), femoral neck (FN) and whole body (WB) using Dual X-ray Absorptiometry in 62 matched pairs; tibial bone parameters were measured using peripheral Quantitative Computer Tomography in 51 matched pairs. Serum C-terminal peptide concentration was measured as a marker of bone resorption at baseline, week-15 and week-32. ANCOVA was used to determine differences between stress fractured recruits and controls. BMD at the LS, WB and FN sites was consistently lower in the stress fracture group (P<0.001). Structural differences between the stress fracture recruits and controls were evident in all slices of the tibia, with the most prominent differences seen at the 38% tibial slice. There was a negative correlation between the bone cross-sectional area and BMD at the 38% tibial slice. There was no difference in serum CTx concentration between stress fracture recruits and matched controls at any stage of training. These results show evidence of fundamental differences in bone mass and structure in stress fracture recruits, and provide useful data on bone risk factor profiles for stress fracture within a healthy military population. Crown Copyright © 2014. Published

An Overview: NASA LeRC Structures Programs

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.

1998-01-01

A workshop on National Structures Programs was held, jointly sponsored by the AIAA Structures Technical Committee, the University of Virginia's Center for Advanced Computational Technology and NASA. The Objectives of the Workshop were to: provide a forum for discussion of current Government-sponsored programs in the structures area; identify high potential research areas for future aerospace systems; and initiate suitable interaction mechanisms with the managers of structures programs. The presentations covered structures programs at NASA, DOD (AFOSR, ONR, ARO and DARPA), and DOE. This publication is the presentation of the Structures and Acoustics Division of the NASA Lewis Research Center. The Structures and Acoustics Division has its genesis dating back to 1943. It is responsible for NASA research related to rotating structures and structural hot sections of both airbreathing and rocket engines. The work of the division encompasses but is not limited to aeroelasticity, structural life prediction and reliability, fatigue and fracture, mechanical components such as bearings, gears, and seals, and aeroacoustics. These programs are discussed and the names of responsible individuals are provided for future reference.

Randomized, controlled, two-arm, interventional, multicenter study on risk-adapted damage control orthopedic surgery of femur shaft fractures in multiple-trauma patients.

PubMed

Rixen, Dieter; Steinhausen, Eva; Sauerland, Stefan; Lefering, Rolf; Maegele, Marc G; Bouillon, Bertil; Grass, Guido; Neugebauer, Edmund A M

2016-01-25

Long bone fractures, particularly of the femur, are common in multiple-trauma patients, but their optimal management has not yet been determined. Although a trend exists toward the concept of "damage control orthopedics" (DCO), current literature is inconclusive. Thus, a need exists for a more specific controlled clinical study. The primary objective of this study was to clarify whether a risk-adapted procedure for treating femoral fractures, as opposed to an early definitive treatment strategy, leads to an improved outcome (morbidity and mortality). The study was designed as a randomized controlled multicenter study. Multiple-trauma patients with femur shaft fractures and a calculated probability of death of 20 to 60 % were randomized to either temporary fracture fixation with external fixation and defined secondary definitive treatment (DCO) or primary reamed nailing (early total care). The primary objective was to reduce the extent of organ failure as measured by the maximum sepsis-related organ failure assessment (SOFA) score. Thirty-four patients were randomized to two groups of 17 patients each. Both groups were comparable regarding sex, age, injury severity score, Glasgow Coma Scale, prothrombin time, base excess, calculated probability of death, and other physiologic variables. The maximum SOFA score was comparable (nonsignificant) between the groups. Regarding the secondary endpoints, the patients with external fixation required a significantly longer ventilation period (p = 0.049) and stayed on the intensive care significantly longer (p = 0.037), whereas the in-hospital length of stay was balanced for both groups. Unfortunately, the study had to be terminated prior to reaching the anticipated sample size because of unexpected low patient recruitment. Thus, the results of this randomized study reflect the ambivalence in the literature. No advantage of the damage control concept could be detected in the treatment of femur fractures in multiple

Controls on wind abrasion patterns through a fractured bedrock landscape

NASA Astrophysics Data System (ADS)

Perkins, J. P.; Finnegan, N. J.

2017-12-01

Wind abrasion is an important geomorphic process for understanding arid landscape evolution on Earth and interpreting the post-fluvial history of Mars. Both the presence and orientation of wind-abraded landforms provide potentially important constraints on paleo-climatic conditions; however, such interpretations can be complicated by lithologic and structural heterogeneity. To explore the influence of pre-existing structure on wind abrasion, we exploit a natural experiment along the 10.2 Ma Lower Rio San Pedro ignimbrite in northern Chile. Here, a 3.2 Ma andesite flow erupted from Cerro de las Cuevas and deposited atop the ignimbrite, supplying wind-transportable sediment and initiating a phase of downwind abrasion. Additionally, the lava flow provides a continually varying degree of upwind topographic shielding along the ignimbrite that is reflected in a range of surface morphologies. Where fully shielded the ignimbrite surface is partially blanketed by sediment. However, as relief decreases the surface morphology shifts from large polygonal structures that emerge due to the concentration of wind abrasion along pre-existing fracture sets, to polygons that are bisected by wind-parallel grooves that cross-cut fracture sets, to linear sets of yardangs. We reconstruct the ignimbrite surface using a high-resolution digital elevation model, and calculate erosion rates ranging from 0.002 to 0.45 mm/kyr that vary strongly with degree of topographic shielding (R2 = 0.97). We use measured abrasion rates together with nearby weather station data to estimate the nondimensional Rouse number and Inertial Parameter for a range of particle sizes. From these calculations, we hypothesize that the change from fracture-controlled to flow-controlled morphology reflects increases in the grain size and inertia of particles in the suspension cloud. Where the ignimbrite experiences persistent high winds, large particles may travel in suspension and are largely insensitive to topographic

Publications of the NASA CELSS (Controlled Ecological Life Support Systems) program

NASA Technical Reports Server (NTRS)

Dufour, P. A.; Solberg, J. L.; Wallace, J. S.

1985-01-01

Publications on research sponsored by the NASA CELSS (controlled ecological life support systems) Program are listed. The bibliography is divided into four areas: (1) human requirements; (2) food production; (3) waste management; and (4) system management and control. The 210 references cover the period from the inception of the CELSS Program (1979) to the present, as well as some earlier publications during the development of the CELSS Program.

Drugs With Anticholinergic Potential and Risk of Falls With Hip Fracture in the Elderly Patients: A Case-Control Study.

PubMed

Machado-Duque, Manuel E; Castaño-Montoya, Juan Pablo; Medina-Morales, Diego A; Castro-Rodríguez, Alejandro; González-Montoya, Alexandra; Machado-Alba, Jorge E

2018-03-01

To determine the association between the use of anticholinergic drugs and the risk of falls with hip fracture in a population older than 60 years. A case-control study in patients older than 60 years with a diagnosis of hip fracture. All drugs dispensed during the previous 30 days were identified. Sociodemographic, clinical, pharmacological (drugs according to the Anticholinergic Risk Scale [ARS]), and polypharmacy variables were analyzed. Falls with hip fracture and type of drug according to the ARS. A total of 300 patients with hip fracture and 600 controls were included. The mean age was 81.6 ± 8.9 years, with female predominance (71.3%). The use of drugs with moderate (odds ratio [OR]: 1.97, 95% confidence interval [CI]: 1.19-3.27) or high ARS scores (OR: 1.83, 95% CI: 1.13-2.96) increased the probability of fracture. There was an association between the use of drugs with anticholinergic properties and the probability of hip fracture in elderly patients and it was possible to establish the level of risk.

A randomized, controlled comparison of home versus institutional rehabilitation of patients with hip fracture.

PubMed

Kuisma, Raija

2002-08-01

To compare ambulation outcomes between home and institutional rehabilitation of patients with hip fracture. Randomized controlled clinical equivalence trial. The Queen Elizabeth Hospital in Hong Kong. Eighty-one patients with hip fracture. Study group patients (40) were discharged directly home from the acute hospital and visited by a physiotherapist an average of 4.6 times. The control group subjects (41) were discharged to a rehabilitation centre for further treatment lasting on average 36.2 days (SD 14.6) and they received physiotherapy daily. Ambulation ability measured on a categorical scale. The mean age of the subjects was 75 years (SD 8.3 years). Females comprised 60% of all the subjects and majority were retired or home makers. Both groups of patients improved in their ambulation ability during their rehabilitation period but neither group achieved their pre-ambulatory status by the time of completion of the study. The study group achieved significantly higher ambulation scores (p < 0.05) for community and household ambulation compared with the control group by the end of the study, a year after operation. Five visits by a physiotherapist in the patient's home after discharge from an acute hospital after surgical treatment for hip fracture yielded better results in ambulation ability than one month of conventional institution-based rehabilitation.

Stirling Convertor Control for a Concept Rover at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Blaze-Dugala, Gina M.

2009-01-01

The U.S. Department of Energy (DOE), Lockheed Martin Space Systems Company (LMSSC), Sunpower Inc., and NASA Glenn Research Center (GRC) have been developing an Advanced Stirling Radioisotope Generator (ASRG) for potential use as an electric power system for space science missions. This generator would make use of the free-piston Stirling cycle to achieve higher conversion efficiency than currently used alternatives. NASA GRC initiated an experiment with an ASRG simulator to demonstrate the functionality of a Stirling convertor on a mobile application, such as a rover. The ASRG simulator made use of two Advanced Stirling Convertors to convert thermal energy from a heat source to electricity. The ASRG simulator was designed to incorporate a minimum amount of support equipment, allowing integration onto a rover powered directly by the convertors. Support equipment to provide control was designed including a linear AC regulator controller, constant power controller, and Li-ion battery charger controller. The ASRG simulator is controlled by a linear AC regulator controller. The rover is powered by both a Stirling convertor and Li-ion batteries. A constant power controller enables the Stirling convertor to maintain a constant power output when additional power is supplied by the Li-ion batteries. A Li-ion battery charger controller limits the charging current and cut off current of the batteries. This paper discusses the design, fabrication, and implementation of these three controllers.

Fracture fixation in the operative management of hip fractures (FAITH): an international, multicentre, randomised controlled trial

PubMed Central

2017-01-01

Summary Background Reoperation rates are high after surgery for hip fractures. We investigated the effect of a sliding hip screw versus cancellous screws on the risk of reoperation and other key outcomes. Methods For this international, multicentre, allocation concealed randomised controlled trial, we enrolled patients aged 50 years or older with a low-energy hip fracture requiring fracture fixation from 81 clinical centres in eight countries. Patients were assigned by minimisation with a centralised computer system to receive a single large-diameter screw with a side-plate (sliding hip screw) or the present standard of care, multiple small-diameter cancellous screws. Surgeons and patients were not blinded but the data analyst, while doing the analyses, remained blinded to treatment groups. The primary outcome was hip reoperation within 24 months after initial surgery to promote fracture healing, relieve pain, treat infection, or improve function. Analyses followed the intention-to-treat principle. This study was registered with ClinicalTrials.gov, number NCT00761813. Findings Between March 3, 2008, and March 31, 2014, we randomly assigned 1108 patients to receive a sliding hip screw (n=557) or cancellous screws (n=551). Reoperations within 24 months did not differ by type of surgical fixation in those included in the primary analysis: 107 (20%) of 542 patients in the sliding hip screw group versus 117 (22%) of 537 patients in the cancellous screws group (hazard ratio [HR] 0.83, 95% CI 0.63–1.09; p=0.18). Avascular necrosis was more common in the sliding hip screw group than in the cancellous screws group (50 patients [9%] vs 28 patients [5%]; HR 1.91, 1.06–3.44; p=0.0319). However, no significant difference was found between the number of medically related adverse events between groups (p=0.82; appendix); these events included pulmonary embolism (two patients [<1%] vs four [1%] patients; p=0.41) and sepsis (seven [1%] vs six [1%]; p=0.79). Interpretation In

Fracture fixation in the operative management of hip fractures (FAITH): an international, multicentre, randomised controlled trial.

PubMed

2017-04-15

Reoperation rates are high after surgery for hip fractures. We investigated the effect of a sliding hip screw versus cancellous screws on the risk of reoperation and other key outcomes. For this international, multicentre, allocation concealed randomised controlled trial, we enrolled patients aged 50 years or older with a low-energy hip fracture requiring fracture fixation from 81 clinical centres in eight countries. Patients were assigned by minimisation with a centralised computer system to receive a single large-diameter screw with a side-plate (sliding hip screw) or the present standard of care, multiple small-diameter cancellous screws. Surgeons and patients were not blinded but the data analyst, while doing the analyses, remained blinded to treatment groups. The primary outcome was hip reoperation within 24 months after initial surgery to promote fracture healing, relieve pain, treat infection, or improve function. Analyses followed the intention-to-treat principle. This study was registered with ClinicalTrials.gov, number NCT00761813. Between March 3, 2008, and March 31, 2014, we randomly assigned 1108 patients to receive a sliding hip screw (n=557) or cancellous screws (n=551). Reoperations within 24 months did not differ by type of surgical fixation in those included in the primary analysis: 107 (20%) of 542 patients in the sliding hip screw group versus 117 (22%) of 537 patients in the cancellous screws group (hazard ratio [HR] 0·83, 95% CI 0·63-1·09; p=0·18). Avascular necrosis was more common in the sliding hip screw group than in the cancellous screws group (50 patients [9%] vs 28 patients [5%]; HR 1·91, 1·06-3·44; p=0·0319). However, no significant difference was found between the number of medically related adverse events between groups (p=0·82; appendix); these events included pulmonary embolism (two patients [<1%] vs four [1%] patients; p=0·41) and sepsis (seven [1%] vs six [1%]; p=0·79). In terms of reoperation rates the sliding hip

Effect of matrix resin on the impact fracture characteristics of graphite-epoxy laminates

NASA Technical Reports Server (NTRS)

Hertzberg, P. E.; Smith, B. W.; Miller, A. G.

1982-01-01

The effect of resin chemistry on basic impact energy absorbent mechanisms exibited by graphite-epoxy composites was investigated. Impact fracture modes and microscopic resin deformation characteristics were examined for 26 NASA-impacted graphite epoxy laminates with different resin chemistries. Discrete specimen fracture modes were identified through cross sectional examination after impact, and subsequently compared with measured glass transition temperatures, cure cycles, and residual impact capabilities. Microscopic resin deformation mechanisms and their overall relationship to impact loading conditions, voids, and resin content were also characterized through scanning electron microscopic examination of separated fracture surfaces.

Statins and hip fracture risk in men: a population-based case-control study.

PubMed

Adams, Annette L; Shi, Jiaxiao M; Reynolds, Kristi; Haque, Reina; Cheetham, T Craig; Kawatkar, Aniket A; Fithian, Donald C; Jacobsen, Steven J

2015-11-01

To estimate the association between hydroxymethylglutaryl-CoA inhibitor (statin) use and hip fracture. We conducted a population-based case-control study. Cases were 6774 male enrollees in a large managed care organization, aged 45 or more years, with an incident hip fracture from 1997 to 2006. Controls without fracture (n = 6774) were matched to cases on age, race, and medical center. Electronic information on pharmaceutical use was used to identify the dispensing of statins from 1991 forward. Overall, 1884 (27.8%) cases and 2150 controls (31.7%) used a statin before index date (matched odds ratio [mOR] = 0.81, 95% confidence interval [CI] = 0.74-0.87). Adjustment for comorbidity burden strengthened the magnitude of the overall association (mOR = 0.68, CI = 0.62-0.74). The adjusted association was similar across age groups but was strongest among men aged 80 years or more (mOR = 0.62, CI = 0.54-0.71) and was most pronounced in African Americans (mOR = 0.43, CI = 0.28-0.64). Greater duration of statin use did not alter the odds ratios. These data add to the growing evidence of a potential protective effect of statin use on bone health. However, these results need to be replicated in a prospective study that can account for confounding by indication which may explain these findings. Copyright © 2015 Elsevier Inc. All rights reserved.

Risk factors for distal radius fracture in postmenopausal women.

PubMed

Xu, Wenting; Ni, Cheng; Yu, Ren; Gu, Guoqing; Wang, Zheren; Zheng, Guoqing

2017-05-01

The aim of this work was to explore the risk factors for distal radius fracture in postmenopausal women. A total of 611 postmenopausal women with distal radius fractures were included. In all, 173 patients with unstable distal radius fractures were included (unstable fracture group), while there were 438 patients with stable distal radius fractures (stable fracture group). The control group comprised 800 postmenopausal women with no fracture. A questionnaire survey was conducted. Compared with the control group, the 611 postmenopausal women with distal radius fractures had a higher body mass index (BMI). Advanced age and higher BMI were more common in the unstable fracture group than in the stable fracture group (P <0.05). A higher proportion of the 611 postmenopausal women with a distal radius fracture had fallen in the last 12 months than in the control group. Comorbidities and the frequency of falls in the last 12 months were higher in the unstable fracture group than in the stable fracture group (P < 0.05). A higher proportion of the control group was taking calcium supplements, while the proportion taking calcium supplementation in the unstable fracture group was lower than that in the stable fracture group (P < 0.05). Osteoporosis in the two fracture groups (P < 0.05) was significantly higher than in the control group and was the highest in the unstable fracture group (P < 0.05). In postmenopausal women, obesity, falls, unknown osteoporosis status, and osteoporosis are associated with high risk of distal radius fracture. If comorbidities and advanced age are also present, this group of persons may be at higher risk for unstable distal radius fractures.

Stress corrosion-controlled rates of mode I fracture propagation in calcareous bedrock

NASA Astrophysics Data System (ADS)

Voigtlaender, Anne; Leith, Kerry; Krautblatter, Michael

2014-05-01

Surface bedrock on natural rock slopes is subject to constant and cyclic environmental stresses (wind, water, wave, ice, seismic or gravitational). Studies indicate that these stresses range up to several hundred kPa, generally too low to cause macroscopic changes in intact rock, although clear evidence of fracture generation, crack propagation and weathering of bedrock illustrates the effect of environmental stresses at the Earth's surface. We suggest that material degradation and its extent, is likely to be controlled by the rate of stress corrosion cracking (SCC). Stress corrosion is a fluid-material reaction, where fluids preferentially react with strained atomic bonds at the tip of developing fractures. Stress corrosion in ferrous and siliceous materials is often accepted as the fracture propagation and degradation rate-controlling process where materials are subject to stresses and fluids. Although evidence for chemical weathering in propagating bedrock fractures is clear in natural environments, the physical system and quantification of stress corrosion in natural rocks is yet to be addressed. Here, we present preliminary data on the relationship between stresses at levels commonly present on natural rock slopes, and material damage resulting from stress corrosion under constant or cyclic tensile loading. We undertake single notch three-point bending tests (SNBT) on fresh calcareous bedrock specimens (1100x100x100mm) over a two-month period. Two beams containing an artificial notch are stressed to 75% of their ultimate strength, and a constant supply of weak acid is applied at the notch tip to enhance chemical reactions. A third, unloaded, beam is also exposed to weak acid in order to elucidate the contribution of stress corrosion cracking to the material degradation. Stresses at the tip of propagating cracks affect the kinetics of the chemical reaction in the specimen exposed to both loading and corrosion, leading to an increase in degradation, and greater

Research reports: 1985 NASA/ASEE Summer Faculty Fellowship Program

NASA Technical Reports Server (NTRS)

Karr, G. R. (Editor); Osborn, T. L. (Editor); Dozier, J. B. (Editor); Freeman, L. M. (Editor)

1986-01-01

A compilation of 40 technical reports on research conducted by participants in the 1985 NASA/ASEE Summer Faculty Fellowship Program at Marshall Space Flight Center (MSFC) is given. Weibull density functions, reliability analysis, directional solidification, space stations, jet stream, fracture mechanics, composite materials, orbital maneuvering vehicles, stellar winds and gamma ray bursts are among the topics discussed.

Spiderweb-like Fractures in Occator Crater

NASA Image and Video Library

2018-01-30

This image shows a complex set of fractures found in the southwestern region of the floor of Occator Crater on Ceres. In this picture, north is at the top. The two intersecting fracture systems (roughly northwest-southeast and southwest-northeast) are part of a larger fault network that extends across Occator's floor. These fractures have been interpreted as evidence that material came up from below and formed a dome shape, as if a piston was pushing Occator's floor from beneath the surface. This may be due to the upwelling of material coming from Ceres' deep interior. An alternative hypothesis is that the deformation is due to volume changes inside a reservoir of icy magma in the shallow subsurface that is in the process of freezing, similar to the change in volume that a bottle of water experiences when put in a freezer. Another set of fractures can be seen parallel to the southwestern wall and is not connected to the Occator fracture network. Dawn took this image during its extended mission on August 17, 2016, from its low-altitude mapping orbit, at a distance of about 240 miles (385 kilometers) above the surface. The image resolution is 120 feet (35 meters) per pixel. The center coordinates are 16 degrees north in latitude and 237 east in longitude. https://photojournal.jpl.nasa.gov/catalog/PIA22091

Dynamics and Control of Orbiting Space Structures NASA Advanced Design Program (ADP)

NASA Technical Reports Server (NTRS)

Cruse, T. A.

1996-01-01

The report summarizes the advanced design program in the mechanical engineering department at Vanderbilt University for the academic years 1994-1995 and 1995-1996. Approximately 100 students participated in the two years of the subject grant funding. The NASA-oriented design projects that were selected included lightweight hydrogen propellant tank for the reusable launch vehicle, a thermal barrier coating test facility, a piezoelectric motor for space antenna control, and a lightweight satellite for automated materials processing. The NASA supported advanced design program (ADP) has been a success and a number of graduates are working in aerospace and are doing design.

The impact of depot medroxyprogesterone acetate on fracture risk: a case-control study from the UK.

PubMed

Kyvernitakis, I; Kostev, K; Nassour, T; Thomasius, F; Hadji, P

2017-01-01

There has been concerning about women receiving depot medroxyprogesterone acetate (DMPA) contraception because of the prolonged hypoestrogenemic state regarding the potential negative effects on bone health. This study showed that DMPA exposure is associated with increased fracture risk and that fracture risk increases with longer DMPA exposure. DMPA has been associated with impaired bone mineral acquisition during adolescence and accelerated bone loss in later life. We performed this large population-based study to assess the association between use of DMPA or combined oral contraceptives and the incident risk of fracture. We identified 4189 women between 20 and 44 years of age with a first-time fracture diagnosis, matched them with 4189 random controls using the Disease Analyzer database and investigated the relation with DMPA exposure. Overall, 11 % of the fracture cases and 7.7 % of the controls had DMPA use recorded. The adjusted OR for developing a fracture in patients with current use of DMPA compared to non-users was 0.97 (95 % CI 0.51-1.86), 2.41 (95 % CI 1.42-4.08), and 1.46 (95 % CI 0.96-2.23) for 1-2, 3-9, and ≥10 prescriptions, respectively. The adjusted OR for developing a fracture in patients with past use of DMPA compared to non-users was 0.96 (95 % CI 0.73-1.26), 1.14 (95 % CI 0.86-1.51), and 1.55 (95 % CI 1.07-2.27) for 1-2, 3-9, and ≥10 prescriptions, respectively. The highest fracture risk was identified in young patients less than 30 years with longer DMPA exposure (≥10 prescriptions; OR 3.04, 95 % CI 1.36-6.81), as well as in patients in the late reproductive years with past use of DMPA (OR 1.72, 95 % CI 1.13-2.63). Our results indicate that DMPA exposure is associated with increased fracture risk and may have negative effects on bone metabolism, resulting in impaired bone mineral acquisition during adolescence and accelerated bone loss in adult life.

NASA flight controllers - Meeting cultural and leadership challenges on the critical path to mission success

NASA Technical Reports Server (NTRS)

Clement, James L., Jr.; Ritsher, Jennifer Boyd

2006-01-01

As part of its preparation for missions to the Moon and Mars, NASA has identified high priority critical path roadmap (CPR) questions, two of which focus on the performance of mission control personnel. NASA flight controllers have always worked in an incredibly demanding setting, but the International Space Station poses even more challenges than prior missions. We surveyed 14 senior ISS flight controllers and a contrasting sample of 12 more junior controllers about the management and cultural challenges they face and the most effective strategies for addressing them. There was substantial consensus among participants on some issues, such as the importance of building a personal relationship with Russian colleagues. Responses from junior and senior controllers differed in some areas, such as training. We frame the results in terms of two CPR questions. We aim to use our results to improve flight controller training.

NASA Dryden Status: Aerospace Control and Guidance Sub-Committee Meeting 109

NASA Technical Reports Server (NTRS)

Jacobson, Steven R.

2012-01-01

NASA Dryden has been engaging in some exciting work that will enable lighter weight and more fuel efficient vehicles through advanced control and dynamics technologies. The main areas of emphasis are Enabling Light-weight Flexible Structures, real time control surface optimization for fuel efficiency and autonomous formation flight. This presentation provides a description of the current and upcoming work in these areas. Additionally, status is for the Dreamchaser pilot training activity and KQ-X autonomous aerial refueling.

Adults With Idiopathic Scoliosis Diagnosed at Youth Experience Similar Physical Activity and Fracture Rate as Controls.

PubMed

Diarbakerli, Elias; Grauers, Anna; Danielsson, Aina; Gerdhem, Paul

2017-04-01

Cross-sectional. To describe physical activity level and fracture rates in adults with idiopathic scoliosis, diagnosed before maturity, and to compare with a control group. A previous study found a lower level of sporting activities in adults treated for idiopathic scoliosis compared with controls. Other studies have shown a lower bone mass in adults with idiopathic scoliosis compared with controls. One thousand two hundred seventy-eight adults (aged 18-71 yr) with idiopathic scoliosis and 214 controls (aged 18-70 yr) were included and answered the International Physical Activity Questionnaire - Short Form (IPAQ-SF) and questions about previous fractures. The three scoliosis treatment groups (untreated n = 360, brace n = 460, and surgically treated n = 458) were compared. Furthermore, a comparison based on onset (juvenile n = 169 or adolescent n = 976) was performed. Achieved weekly moderate activity level and metabolic equivalent task (MET) minutes/week were assessed for patients and controls. Statistical comparisons were made with analysis of covariance with adjustments for age, body mass index, and sex. The proportion achieving weekly moderate activity level was 962 out of 1278 for individuals with idiopathic scoliosis (75%) and 157 out of 214 (73%) for controls (P = 0.40). The scoliosis patients reported 2016 MET-minutes/week (median value) and the controls 2456 (P = 0.06). Fracture rates did not differ (P = 0.72). Fewer surgically treated individuals achieved moderate activity level (P = 0.046) compared with the untreated and the previously braced individuals. No difference was seen regarding MET-minutes/week (P = 0.86). No differences were seen between individuals with a juvenile onset compared with individuals with an adolescent onset (all P ≥ 0.05). Adults with idiopathic scoliosis have similar physical activity level and do not sustain more fractures compared with controls. Adults with surgically treated

The Integration of COTS/GOTS within NASA's HST Command and Control System

NASA Technical Reports Server (NTRS)

Pfarr, Thomas; Reis, James E.; Obenschain, Arthur F. (Technical Monitor)

2001-01-01

NASA's mission critical Hubble Space Telescope (HST) command and control system has been re-engineered with COTS/GOTS and minimal custom code. This paper focuses on the design of this new HST Control Center System (CCS) and the lessons learned throughout its development. CCS currently utilizes 31 COTS/GOTS products with an additional 12 million lines of custom glueware code; the new CCS exceeds the capabilities of the original system while significantly reducing the lines of custom code by more than 50%. The lifecycle of COTS/GOTS products will be examined including the pack-age selection process, evaluation process, and integration process. The advantages, disadvantages, issues, concerns, and lessons teamed for integrating COTS/GOTS into the NASA's mission critical HST CCS will be examined in detail. Command and control systems designed with traditional custom code development efforts will be compared with command and control systems designed with new development techniques relying heavily on COTS/COTS integration. This paper will reveal the many hidden costs of COTS/GOTS solutions when compared to traditional custom code development efforts; this paper will show the high cost of COTS/GOTS solutions including training expenses, consulting fees, and long-term maintenance expenses.

Use of antiepileptic drugs and risk of fractures: case-control study among patients with epilepsy.

PubMed

Souverein, P C; Webb, D J; Weil, J G; Van Staa, T P; Egberts, A C G

2006-05-09

To study the association between use of antiepileptic drugs (AEDs) and risk of fractures. The authors obtained data from the General Practice Research Database (GPRD). A case-control study was nested within a cohort of patients with active epilepsy. Cases were patients with a first fracture after cohort entry. Up to four controls were matched to each case by practice, sex, year of birth, timing of first epilepsy diagnosis, index date, and duration of GPRD history. Cumulative exposure to AEDs was assessed by summing the duration of all AED prescriptions. A distinction was made between AEDs that induce the hepatic cytochrome P-450 enzyme system and AEDs that do not. Medical conditions and drugs known to be associated with bone metabolism or falls were evaluated as potential confounders. Conditional logistic regression analysis was used to calculate odds ratios (ORs) and 95% CIs. The study population comprised 1,018 cases and 1,842 matched controls. The risk of fractures increased with cumulative duration of exposure (p for trend < 0.001), with the strongest association for greater than 12 years of use: adjusted OR 4.15 (95% CI 2.71 to 6.34). Risk estimates were higher in women than in men. There was no difference between users of AEDs that induce and AEDs that do not induce the hepatic cytochrome P-450 system. Long-term use of AEDs was associated with an increased risk of fractures, especially in women. More research on mechanisms of AED-induced bone breakdown and female vulnerability to the effects of AEDs on bone health is warranted.

Television, computer, and video viewing; physical activity; and upper limb fracture risk in children: a population-based case control study.

PubMed

Ma, Deqiong; Jones, Graeme

2003-11-01

The effect of physical activity on upper limb fractures was examined in this population-based case control study with 321 age- and gender-matched pairs. Sports participation increased fracture risk in boys and decreased risk in girls. Television viewing had a deleterious dose response association with wrist and forearm fractures while light physical activity was protective. The aim of this population-based case control study was to examine the association between television, computer, and video viewing; types and levels of physical activity; and upper limb fractures in children 9-16 years of age. A total of 321 fracture cases and 321 randomly selected individually matched controls were studied. Television, computer, and video viewing and types and levels of physical activity were determined by interview-administered questionnaire. Bone strength was assessed by DXA and metacarpal morphometry. In general, sports participation increased total upper limb fracture risk in boys and decreased risk in girls. Gender-specific risk estimates were significantly different for total, contact, noncontact, and high-risk sports participation as well as four individual sports (soccer, cricket, surfing, and swimming). In multivariate analysis, time spent television, computer, and video viewing in both sexes was positively associated with wrist and forearm fracture risk (OR 1.6/category, 95% CI: 1.1-2.2), whereas days involved in light physical activity participation decreased fracture risk (OR 0.8/category, 95% CI: 0.7-1.0). Sports participation increased hand (OR 1.5/sport, 95% CI: 1.1-2.0) and upper arm (OR 29.8/sport, 95% CI: 1.7-535) fracture risk in boys only and decreased wrist and forearm fracture risk in girls only (OR 0.5/sport, 95% CI: 0.3-0.9). Adjustment for bone density and metacarpal morphometry did not alter these associations. There is gender discordance with regard to sports participation and fracture risk in children, which may reflect different approaches to sport

Serum vitamin E concentrations among highly functioning hip fracture patients are higher than in nonfracture controls

PubMed Central

D’Adamo, Christopher R.; Shardell, Michelle D.; Hicks, Gregory E.; Orwig, Denise L.; Hochberg, Marc C.; Semba, Richard D.; Yu-Yahiro, Janet A.; Ferrucci, Luigi; Magaziner, Jay S.; Miller, Ram R.

2014-01-01

Malnutrition after hip fracture is common and associated with poor outcomes and protracted recovery. Low concentrations of vitamin E have been associated with incident decline in physical function among older adults and may, therefore, be particularly important to functionally compromised patients hip fracture patients. Serum concentrations of α-tocopherol and γ-tocopherol, the 2 major forms of vitamin E, were assessed in 148 female hip fracture patients 65 years or older from the Baltimore Hip Studies cohort 4 around the time of fracture (baseline) and at 2, 6, and 12 month postfracture follow-up visits (recovery). It was hypothesized that mean concentrations of both forms of vitamin E among these hip fracture patients would be lowest at the baseline visit and increase at each study visit during the year after fracture. Linear regression and generalized estimating equations were used to assess changes in vitamin E concentrations after adjustment for covariates and to determine predictors of vitamin E concentrations at baseline and throughout recovery. It was also hypothesized that vitamin E concentrations shortly after hip fracture would be lower than those in nonfracture controls after adjustment for covariates. To evaluate this hypothesis, linear regression was used to perform adjusted comparisons of baseline vitamin E concentrations among Baltimore Hip Studies cohort 4 participants to 1076 older women without history of hip fracture from the Women’s Health and Aging Study I, Invecchiare in Chianti Study, and the National Health and Nutrition Examination Surveys. Mean α-tocopherol was lowest at baseline, and time from fracture to blood draw was positively associated with baseline α-tocopherol (P = .005). Mean γ-tocopherol did not change appreciably throughout the year after fracture, although it fluctuated widely within individuals. Serum concentrations of α-tocopherol and γ-tocopherol were highest among the hip fracture population after adjustment (P

Resolving controversies in hip fracture care: the need for large collaborative trials in hip fractures.

PubMed

Bhandari, Mohit; Sprague, Sheila; Schemitsch, Emil H

2009-07-01

Hip fractures are a significant cause of morbidity and mortality worldwide and the burden of disability associated with hip fractures globally vindicate the need for high-quality research to advance the care of patients with hip fractures. Historically, large, multi-centre randomized controlled trials have been rare in the orthopaedic trauma literature. Similar to other medical specialties, orthopaedic research is currently undergoing a paradigm shift from single centre initiatives to larger collaborative groups. This is evident with the establishment of several collaborative groups in Canada, in the United States, and in Europe, which has proven that multi-centre trials can be extremely successful in orthopaedic trauma research.Despite ever increasing literature on the topic of his fractures, the optimal treatment of hip fractures remains unknown and controversial. To resolve this controversy large multi-national collaborative randomized controlled trials are required. In 2005, the International Hip Fracture Research Collaborative was officially established following funding from the Canadian Institute of Health Research International Opportunity Program with the mandate of resolving controversies in hip fracture management. This manuscript will describe the need, the information, the organization, and the accomplishments to date of the International Hip Fracture Research Collaborative.

Effects of Extremely High ’G’ Acceleration Forces on NASA’s Control and Space Exposed Tomato Seeds

DTIC Science & Technology

1991-12-01

mechanical shock test; tomatoes staked 28 and interplanted with dwarf marigolds for nematode protection of tomatoes 28 NASA control seed mechanical shock...plants transplanted to garden Figure 27. NASA control seed mechanical shock test; tomatoes staked and interplanted with dwarf marigolds for nematode

Prescribing by general practitioners after an osteoporotic fracture.

PubMed

Torgerson, D J; Dolan, P

1998-06-01

Osteoporosis is a major cause of morbidity and cost. Patients sustaining one osteoporotic fracture are at increased risk of having another fracture. The objective of this study was to examine the use of "bone drugs" for the prevention of further osteoporotic fractures among patients who have had a "typical" osteoporotic fracture. This study took a random sample of 300 women aged 50 and over who had sustained either a vertebral, hip or Colles fracture in 1995 from the General Practice Research Database (GPRD) and compared their use of bone drugs with 300 age and practice matched controls. Compared with age and practice matched control patients only vertebral fracture patients showed a statistically significant increase in the use of bone drugs in the year after fracture (39% and 2% for cases and controls respectively; 95% CI of difference 27% to 47%). Etidronate was the most commonly used compound. The majority of patients sustaining an osteoporotic fracture are not prescribed any pharmaceutical agents for the secondary prevention of fracture one year after a primary fracture.

Can paramedics use FRAX (the WHO Fracture Risk Assessment Tool) to help GPs improve future fracture risk in patients who fall? Protocol for a randomised controlled feasibility study.

PubMed

Clarke, Shane; Bradley, Rachel; Simmonds, Bethany; Salisbury, Chris; Benger, Jonathan; Marques, Elsa; Greenwood, Rosemary; Shepstone, Lee; Robinson, Maria; Appleby-Fleming, John; Gooberman-Hill, Rachael

2014-09-03

Currently identification, and therefore, management of patients at risk of osteoporotic fracture in the UK is suboptimal. As the majority of patients who fracture have fallen, it follows that people who fall can usefully be targeted in any programme that aims to reduce osteoporotic fracture. Targeting vulnerable patients who are likely to benefit from intervention may help shift the management of fracture prevention into primary care, away from emergency departments. Paramedics who attend to patients who have fallen may be well placed to assess future fracture risk, using the Fracture Risk Assessment Tool (FRAX) and communicate that information directly to general practitioners (GPs). This feasibility study takes the form of a pragmatic, randomised controlled trial aimed at exploring and refining issues of study design, recruitment, retention, sample size and acceptability preceding a large-scale study with fracture as the end point. Patients (aged >50) who fall, call an ambulance, are attended by a study paramedic and give verbal consent will be asked FRAX and fall questions. Patients who subsequently formally consent to participation will be randomised to control (usual care) or intervention groups. Intervention will constitute transmission of calculated future fracture risk to the patients' GP with suitable, evidence-based recommendations for investigation or treatment. 3 months after the index fall, data (proportion of patients in each group undergoing investigation or starting new treatment, quality of life and health economic) will be collected and analysed using descriptive statistics. A nested qualitative study will explore issues of acceptability and study design with patients, paramedics and GPs. This protocol was approved by NRES Committee South Central Oxford C in October 2012. Research Ethics Committee ref.12/SC/0604. The study findings will be disseminated through peer-reviewed journals, conference presentations and local public events. A publication

Posterior paramedian subrhomboidal analgesia versus thoracic epidural analgesia for pain control in patients with multiple rib fractures.

PubMed

Shelley, Casey L; Berry, Stepheny; Howard, James; De Ruyter, Martin; Thepthepha, Melissa; Nazir, Niaman; McDonald, Tracy; Dalton, Annemarie; Moncure, Michael

2016-09-01

Rib fractures are common in trauma admissions and are associated with an increased risk of pulmonary complications, intensive care unit admissions, and mortality. Providing adequate pain control in patients with multiple rib fractures decreases the risk of adverse events. Thoracic epidural analgesia is currently the preferred method for pain control. This study compared outcomes in patients with multiple acute rib fractures treated with posterior paramedian subrhomboidal (PoPS) analgesia versus thoracic epidural analgesia (TEA). This prospective study included 30 patients with three or more acute rib fractures admitted to a Level I trauma center. Thoracic epidural analgesia or PoPS catheters were placed, and local anesthesia was infused. Data were collected including patients' pain level, adjunct morphine equivalent use, adverse events, length of stay, lung volumes, and discharge disposition. Nonparametric tests were used and two-sided p < 0.05 were considered statistically significant. Nineteen (63%) of 30 patients received TEA and 11 (37%) of 30 patients received PoPS. Pain rating was lower in the PoPS group (2.5 vs. 5; p = 0.03) after initial placement. Overall, there was no other statistically significant difference in pain control or use of oral morphine adjuncts between the groups. Hypotension occurred in eight patients, 75% with TEA and only 25% with PoPS. No difference was found in adverse events, length of stay, lung volumes, or discharge disposition. In patients with rib fractures, PoPS analgesia may provide pain control equivalent to TEA while being less invasive and more readily placed by a variety of hospital staff. This pilot study is limited by its small sample size, and therefore additional studies are needed to prove equivalence of PoPS compared to TEA. Therapeutic study, level IV.

Gravity-Driven Hydraulic Fractures

NASA Astrophysics Data System (ADS)

Germanovich, L. N.; Garagash, D.; Murdoch, L. C.; Robinowitz, M.

2014-12-01

This study is motived by a new method for disposing of nuclear waste by injecting it as a dense slurry into a hydraulic fracture that grows downward to great enough depth to permanently isolate the waste. Disposing of nuclear waste using gravity-driven hydraulic fractures is mechanically similar to the upward growth of dikes filled with low density magma. A fundamental question in both applications is how the injected fluid controls the propagation dynamics and fracture geometry (depth and breadth) in three dimensions. Analog experiments in gelatin [e.g., Heimpel and Olson, 1994; Taisne and Tait, 2009] show that fracture breadth (the short horizontal dimension) remains nearly stationary when the process in the fracture "head" (where breadth is controlled) is dominated by solid toughness, whereas viscous fluid dissipation is dominant in the fracture tail. We model propagation of the resulting gravity-driven (buoyant or sinking), finger-like fracture of stationary breadth with slowly varying opening along the crack length. The elastic response to fluid loading in a horizontal cross-section is local and can be treated similar to the classical Perkins-Kern-Nordgren (PKN) model of hydraulic fracturing. The propagation condition for a finger-like crack is based on balancing the global energy release rate due to a unit crack extension with the rock fracture toughness. It allows us to relate the net fluid pressure at the tip to the fracture breadth and rock toughness. Unlike the PKN fracture, where breadth is known a priori, the final breadth of a finger-like fracture is a result of processes in the fracture head. Because the head is much more open than the tail, viscous pressure drop in the head can be neglected leading to a 3D analog of Weertman's hydrostatic pulse. This requires relaxing the local elasticity assumption of the PKN model in the fracture head. As a result, we resolve the breadth, and then match the viscosity-dominated tail with the 3-D, toughness

Mechanics in the Production of Mandibular Fractures: A Clinical, Retrospective Case-Control Study

PubMed Central

Yang, Rongtao; Li, Zhi; Li, Zubing

2016-01-01

As the mandible is susceptible to fracture, the aim of this study was to use multivariate logistic regression analysis to identify and distinguish various internal factors that may influence the location of mandibular fractures. The study included 1131 patients with maxillofacial fractures during the period from January 2000 to December 2009 to evaluate the association of mandibular fracture location (unilateral symphysis, body, angle, condylar, or bilateral condylar fractures) with various internal factors. Among the 1131 patients, 869 had mandibular fractures. Data on age, sex, soft tissue injuries, dental trauma, and maxillofacial fracture type were collected and analyzed using multivariate logistic regression. In total, 387, 210, 139, 319, and 172 patients were diagnosed with unilateral symphysis, body, angle, unilateral, or bilateral condylar fractures, respectively. The dental trauma in patients with bilateral condylar fractures differed from that in patients with unilateral condylar fractures. Patients with mandibular fracture (unilateral symphysis, body, unilateral or bilateral condylar) possessed an approximately equal risk of soft tissue injuries in the mandible. Patients with either unilateral or bilateral condylar fractures were associated with a low risk of mandibular angle fracture (OR < 1). Similarly, patients with mandibular angle fracture were associated with a low risk of unilateral or bilateral condylar fractures (OR < 1). Moreover, patients with symphysis fracture were associated with a low risk of bilateral condylar fractures (90 of 387 [23.3%], OR 0.899). By contrast, patients with bilateral condylar fractures were associated with a high risk of symphysis fracture (90 of 172 [52.3%], OR 17.38). Patients with condylar fractures, particularly those with bilateral condylar fractures, were infrequently associated with secondary mandibular fractures. Mandibular fractures tended to have less of an association with midfacial fractures. The occurrence

Fragility fractures and bone mineral density in HIV positive women: a case-control population-based study.

PubMed

Prior, J; Burdge, D; Maan, E; Milner, R; Hankins, C; Klein, M; Walmsley, S

2007-10-01

This Canadian study of bone health showed that HIV+ women were more likely to have had fragility fractures (OR 1.7) but had BMD values that were not different than women from a national population-based cohort. Given that 17.5 million women globally are HIV-infected and living longer on anti-retroviral therapy (ART+), it is essential to determine whether they are at risk for osteoporosis as is currently assumed. Assessment of osteoporosis risk factors and lifetime low-trauma (fragility) fracture history used a common interviewer-administered questionnaire and phantom-adjusted bone mineral density (BMD). This study compared HIV+ Canadian women with age- and region-matched control women (1:3) from a national population-based study of osteoporosis. One hundred and thirty-eight HIV+ women (100 ART+, 38 ART-) were compared with 402 controls. There were no differences in age (37.7 vs. 38.0 years), BMI (25.0 vs. 26.2), family history of osteoporosis, exercise history, alcohol or calcium intakes, age at menarche, oral contraceptive use or parity. HIV+ cases included more Aboriginal and Black women (12.5% and 16.2 vs. 2% and 1%, respectively), smoked and used injection drugs (53%) more, were more often treated with glucocorticoids, had oligomenorrhea, and reported 10-kg weight cycling. Significantly more HIV+ women reported lifetime fragility fractures (26.1% vs. 17.3; OR 1.7, 95% CI 1.1, 2.6). HIV+ and control women did not differ in BMD: spine 1.0 +/- 0.12 vs.1.0 +/- 0.14 g/cm(2) (diff. 0.0, 95% CI -0.27, 0.27) or total femur 0.91 +/- 0.15 vs. 0.93 +/- 0.12 g/cm(2) (diff 0.02, 95% CI +0.005, -0.045). HIV+ women reported significantly more past osteoporotic fractures than population-based controls despite normal BMD. Research is needed to assess bone microarchitecture and develop a reliable fracture risk assessment tool for HIV+ women.

Fluid driven fracture mechanics in highly anisotropic shale: a laboratory study with application to hydraulic fracturing

NASA Astrophysics Data System (ADS)

Gehne, Stephan; Benson, Philip; Koor, Nick; Enfield, Mark

2017-04-01

The finding of considerable volumes of hydrocarbon resources within tight sedimentary rock formations in the UK led to focused attention on the fundamental fracture properties of low permeability rock types and hydraulic fracturing. Despite much research in these fields, there remains a scarcity of available experimental data concerning the fracture mechanics of fluid driven fracturing and the fracture properties of anisotropic, low permeability rock types. In this study, hydraulic fracturing is simulated in a controlled laboratory environment to track fracture nucleation (location) and propagation (velocity) in space and time and assess how environmental factors and rock properties influence the fracture process and the developing fracture network. Here we report data on employing fluid overpressure to generate a permeable network of micro tensile fractures in a highly anisotropic shale ( 50% P-wave velocity anisotropy). Experiments are carried out in a triaxial deformation apparatus using cylindrical samples. The bedding planes are orientated either parallel or normal to the major principal stress direction (σ1). A newly developed technique, using a steel guide arrangement to direct pressurised fluid into a sealed section of an axially drilled conduit, allows the pore fluid to contact the rock directly and to initiate tensile fractures from the pre-defined zone inside the sample. Acoustic Emission location is used to record and map the nucleation and development of the micro-fracture network. Indirect tensile strength measurements at atmospheric pressure show a high tensile strength anisotropy ( 60%) of the shale. Depending on the relative bedding orientation within the stress field, we find that fluid induced fractures in the sample propagate in two of the three principal fracture orientations: Divider and Short-Transverse. The fracture progresses parallel to the bedding plane (Short-Transverse orientation) if the bedding plane is aligned (parallel) with the

NASA Airborne Astronomy Ambassadors (AAA) Professional Development and NASA Connections

NASA Astrophysics Data System (ADS)

Backman, D. E.; Clark, C.; Harman, P. K.

2017-12-01

NASA's Airborne Astronomy Ambassadors (AAA) program is a three-part professional development (PD) experience for high school physics, astronomy, and earth science teachers. AAA PD consists of: (1) blended learning via webinars, asynchronous content learning, and in-person workshops, (2) a STEM immersion experience at NASA Armstrong's B703 science research aircraft facility in Palmdale, California, and (3) ongoing opportunities for connection with NASA astrophysics and planetary science Subject Matter Experts (SMEs). AAA implementation in 2016-18 involves partnerships between the SETI Institute and seven school districts in northern and southern California. AAAs in the current cohort were selected by the school districts based on criteria developed by AAA program staff working with WestEd evaluation consultants. The selected teachers were then randomly assigned by WestEd to a Group A or B to support controlled testing of student learning. Group A completed their PD during January - August 2017, then participated in NASA SOFIA science flights during fall 2017. Group B will act as a control during the 2017-18 school year, then will complete their professional development and SOFIA flights during 2018. A two-week AAA electromagnetic spectrum and multi-wavelength astronomy curriculum aligned with the Science Framework for California Public Schools and Next Generation Science Standards was developed by program staff for classroom delivery. The curriculum (as well as the AAA's pre-flight PD) capitalizes on NASA content by using "science snapshot" case studies regarding astronomy research conducted by SOFIA. AAAs also interact with NASA SMEs during flight weeks and will translate that interaction into classroom content. The AAA program will make controlled measurements of student gains in standards-based learning plus changes in student attitudes towards STEM, and observe & record the AAAs' implementation of curricular changes. Funded by NASA: NNX16AC51

Fluoride in drinking water and risk of hip fracture in the UK: a case-control study.

PubMed

Hillier, S; Cooper, C; Kellingray, S; Russell, G; Hughes, H; Coggon, D

2000-01-22

Although the benefits of water fluoridation for dental health are widely accepted, concerns remain about possible adverse effects, particularly effects on bone. Several investigators have suggested increased rates of hip fracture in places with high concentrations of fluoride in drinking water, but this finding has not been consistent, possibly because of unrecognised confounding effects. We did a case-control study of men and women aged 50 years and older from the English county of Cleveland, and compared patients with hip fracture with community controls. Current addresses were ascertained for all participants; for those who agreed to an interview and who passed a mental test, more detailed information was obtained about lifetime residential history and exposure to other known and suspected risk factors for hip fracture. Exposures to fluoride in water were estimated from the residential histories and from information provided by water suppliers. Analysis was by logistic regression. 914 cases and 1196 controls were identified, of whom 514 and 527, respectively, were interviewed. Among those interviewed, hip fracture was strongly associated with low body-mass index (p for trend <0.001) and physical inactivity (p for trend <0.001). Estimated average lifetime exposure to fluoride in drinking water ranged from 0.15 to 1.79 ppm. Current residence in Hartlepool was a good indicator for high lifetime exposure to fluoride. After adjustment for potential confounders, the odds ratio associated with an average lifetime exposure to fluoride > or =0.9 ppm was 1.0 [95% CI 0.7-1.5]. There is a low risk of hip fracture for people ingesting fluoride in drinking water at concentrations of about 1 ppm. This low risk should not be a reason for withholding fluoridation of water supplies.

Fourier transform infrared imaging of femoral neck bone: reduced heterogeneity of mineral-to-matrix and carbonate-to-phosphate and more variable crystallinity in treatment-naive fracture cases compared with fracture-free controls.

PubMed

Gourion-Arsiquaud, Samuel; Lukashova, Lyudmilla; Power, Jon; Loveridge, Nigel; Reeve, Jonathan; Boskey, Adele L

2013-01-01

After the age of 60 years, hip fracture risk strongly increases, but only a fifth of this increase is attributable to reduced bone mineral density (BMD, measured clinically). Changes in bone quality, specifically bone composition as measured by Fourier transform infrared spectroscopic imaging (FTIRI), also contribute to fracture risk. Here, FTIRI was applied to study the femoral neck and provide spatially derived information on its mineral and matrix properties in age-matched fractured and nonfractured bones. Whole femoral neck cross sections, divided into quadrants along the neck's axis, from 10 women with hip fracture and 10 cadaveric controls were studied using FTIRI and micro-computed tomography. Although 3-dimensional micro-CT bone mineral densities were similar, the mineral-to-matrix ratio was reduced in the cases of hip fracture, confirming previous reports. New findings were that the FTIRI microscopic variation (heterogeneity) of the mineral-to-matrix ratio was substantially reduced in the fracture group as was the heterogeneity of the carbonate-to-phosphate ratio. Conversely, the heterogeneity of crystallinity was increased. Increased variation of crystallinity was statistically associated with reduced variation of the carbonate-to-phosphate ratio. Anatomical variation in these properties between the different femoral neck quadrants was reduced in the fracture group compared with controls. Although our treatment-naive patients had reduced rather than increased bending resistance, these changes in heterogeneity associated with hip fracture are in another way comparable to the effects of experimental bisphosphonate therapy, which decreases heterogeneity and other indicators of bone's toughness as a material. Copyright © 2013 American Society for Bone and Mineral Research.

A review of fracture mechanics life technology

NASA Technical Reports Server (NTRS)

Thomas, J. M.; Besuner, P. M.; Harris, D. O.

1985-01-01

Current lifetime prediction technology for structural components subjected to cyclic loads was reviewed. The central objectives of the project were to report the current state of and recommend future development of fracture mechanics-based analytical tools for modeling and forecasting subcritical fatigue crack growth in structures. Of special interest to NASA was the ability to apply these tools to practical engineering problems and the developmental steps necessary to bring vital technologies to this stage. A survey of published literature and numerous discussions with experts in the field of fracture mechanics life technology were conducted. One of the key points made is that fracture mechanics analyses of crack growth often involve consideration of fatigue and fracture under extreme conditions. Therefore, inaccuracies in predicting component lifetime will be dominated by inaccuracies in environment and fatigue crack growth relations, stress intensity factor solutions, and methods used to model given loads and stresses. Suggestions made for reducing these inaccuracies include: development of improved models of subcritical crack growth, research efforts aimed at better characterizing residual and assembly stresses that can be introduced during fabrication, and more widespread and uniform use of the best existing methods.

Dynamic wind-tunnel testing of active controls by the NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Abel, I.; Doggett, R. V.; Newsom, J. R.; Sandford, M.

1984-01-01

Dynamic wind-tunnel testing of active controls by the NASA Langley Research Center is presented. Seven experimental studies that were accomplished to date are described. Six of the studies focus on active flutter suppression. The other focuses on active load alleviation. In addition to presenting basic results for these experimental studies, topics including model design and construction, control law synthesis, active control system implementation, and wind-tunnel test techniques are discussed.

Effectiveness of multimodal pain management after bipolar hemiarthroplasty for hip fracture: a randomized, controlled study.

PubMed

Kang, Hyun; Ha, Yong-Chan; Kim, Jin-Yun; Woo, Young-Cheol; Lee, Jae-Sung; Jang, Eui-Chan

2013-02-20

Appropriate pain management affects outcome after hip fracture surgery. Although multimodal pain management is commonly used for pain control for patients undergoing elective surgery, few studies have evaluated its use in those undergoing hip fracture surgery. This prospective randomized study was designed to determine the clinical value of multimodal pain management with preemptive pain medication and intraoperative periarticular multimodal drug injections in patients undergoing bipolar hip hemiarthroplasty. Of eighty-two cognitively intact elderly patients about to undergo bipolar hemiarthroplasty after a hip fracture, forty-three were randomly assigned to receive preemptive pain medication and intraoperative periarticular injections (Group I) and thirty-nine were assigned to not receive preemptive medication and injections (Group II). These two groups were compared with regard to the pain level on postoperative days one, four, and seven; at discharge; and when they started walking and standing exercises. Total amounts of fentanyl used, the frequency of use of patient-controlled analgesia, patient satisfaction at discharge, and perioperative complications were recorded. Group I had a lower pain level than Group II on postoperative days one and four, but no intergroup difference in pain level was observed on postoperative day seven. The total amount of fentanyl used and the frequency of use of patient-controlled analgesia were also lower in Group I. Patient satisfaction at discharge was higher in Group I. No significant intergroup differences were found in the times until the patients walked or performed standing exercises or in the complications. Multimodal pain management provides additional pain relief until the fourth postoperative day, improves patient satisfaction at discharge, and reduces total narcotic consumption for postoperative pain management after hip hemiarthroplasty for hip fractures.

The value of arthroscopy in the treatment of complex ankle fractures - a protocol of a randomised controlled trial.

PubMed

Braunstein, Mareen; Baumbach, Sebastian F; Regauer, Markus; Böcker, Wolfgang; Polzer, Hans

2016-05-12

An anatomical reconstruction of the ankle congruity is the important prerequisite in the operative treatment of acute ankle fractures. Despite anatomic restoration patients regularly suffer from residual symptoms after these fractures. There is growing evidence, that a poor outcome is related to the concomitant traumatic intra-articular pathology. By supplementary ankle arthroscopy anatomic reduction can be confirmed and associated intra-articular injuries can be treated. Nevertheless, the vast majority of complex ankle fractures are managed by open reduction and internal fixation (ORIF) only. Up to now, the effectiveness of arthroscopically assisted fracture treatment (AORIF) has not been conclusively determined. Therefore, a prospective randomised study is needed to sufficiently evaluate the effect of AORIF compared to ORIF in complex ankle fractures. We perform a randomised controlled trial at Munich University Clinic enrolling patients (18-65 years) with an acute ankle fracture (AO 44 A2, A3, B2, B3, C1 - C3 according to AO classification system). Patients meeting the inclusion criteria are randomised to either intervention group (AORIF, n = 37) or comparison group (ORIF, n = 37). Exclusion criteria are fractures classified as AO type 44 A1 or B1, pilon or plafond-variant injury or open fractures. Primary outcome is the AOFAS Score (American Orthopaedic Foot and Ankle Society). Secondary outcome parameter are JSSF Score (Japanese Society of Surgery of the Foot), Olerud and Molander Score, Karlsson Score, Tegner Activity Scale, SF-12, radiographic analysis, arthroscopic findings of intra-articular lesions, functional assessments, time to return to work/sports and complications. This study protocol is accordant to the SPIRIT 2013 recommendation. Statistical analysis will be performed using SPSS 22.0 (IBM). The subjective and functional outcome of complex ankle fractures is regularly unsatisfying. As these injuries are very common it is essential to

NASA-STD-4005 and NASA-HDBK-4006, LEO Spacecraft Solar Array Charging Design Standard

NASA Technical Reports Server (NTRS)

Ferguson, Dale C.

2007-01-01

Two new NASA Standards are now official. They are the NASA LEO Spacecraft Charging Design Standard (NASA-STD-4005) and the NASA LEO Spacecraft Charging Design Handbook (NASA-HDBK-4006). They give the background and techniques for controlling solar array-induced charging and arcing in LEO. In this paper, a brief overview of the new standards is given, along with where they can be obtained and who should be using them.

Upgrading NASA/DOSE laser ranging system control computers

NASA Technical Reports Server (NTRS)

Ricklefs, Randall L.; Cheek, Jack; Seery, Paul J.; Emenheiser, Kenneth S.; Hanrahan, William P., III; Mcgarry, Jan F.

1993-01-01

Laser ranging systems now managed by the NASA Dynamics of the Solid Earth (DOSE) and operated by the Bendix Field Engineering Corporation, the University of Hawaii, and the University of Texas have produced a wealth on interdisciplinary scientific data over the last three decades. Despite upgrades to the most of the ranging station subsystems, the control computers remain a mix of 1970's vintage minicomputers. These encompass a wide range of vendors, operating systems, and languages, making hardware and software support increasingly difficult. Current technology allows replacement of controller computers at a relatively low cost while maintaining excellent processing power and a friendly operating environment. The new controller systems are now being designed using IBM-PC-compatible 80486-based microcomputers, a real-time Unix operating system (LynxOS), and X-windows/Motif IB, and serial interfaces have been chosen. This design supports minimizing short and long term costs by relying on proven standards for both hardware and software components. Currently, the project is in the design and prototyping stage with the first systems targeted for production in mid-1993.

Surgery versus conservative treatment in patients with type A distal radius fractures, a randomized controlled trial

PubMed Central

2014-01-01

Background Fractures of the distal radius are common and account for an estimated 17% of all fractures diagnosed. Two-thirds of these fractures are displaced and require reduction. Although distal radius fractures, especially extra-articular fractures, are considered to be relatively harmless, inadequate treatment may result in impaired function of the wrist. Initial treatment according to Dutch guidelines consists of closed reduction and plaster immobilisation. If fracture redisplacement occurs, surgical treatment is recommended. Recently, the use of volar locking plates has become more popular. The aim of this study is to compare the functional outcome following surgical reduction and fixation with a volar locking plate with the functional outcome following closed reduction and plaster immobilisation in patients with displaced extra-articular distal radius fractures. Design This single blinded randomised controlled trial will randomise between open reduction and internal fixation with a volar locking plate (intervention group) and closed reduction followed by plaster immobilisation (control group). The study population will consist of all consecutive adult patients who are diagnosed with a displaced extra-articular distal radius fracture, which has been adequately reduced at the Emergency Department. The primary outcome (functional outcome) will be assessed by means of the Disability Arm Shoulder Hand Score (DASH). Secondary outcomes comprise the Patient-Rated Wrist Evaluation score (PRWE), quality of life, pain, range of motion, radiological parameters, complications and cross-overs. Since the treatment allocated involves a surgical procedure, randomisation status will not be blinded. However, the researcher assessing the outcome at one year will be unaware of the treatment allocation. In total, 90 patients will be included and this trial will require an estimated time of two years to complete and will be conducted in the Academic Medical Centre Amsterdam and

Fracture controls on valley persistence: the Cairngorm Granite pluton, Scotland

NASA Astrophysics Data System (ADS)

Hall, A. M.; Gillespie, M. R.

2017-09-01

Valleys are remarkably persistent features in many different tectonic settings, but the reasons for this persistence are rarely explored. Here, we examine the structural controls on valleys in the Cairngorms Mountains, Scotland, part of the passive margin of the eastern North Atlantic. We consider valleys at three scales: straths, glens and headwater valleys. The structural controls on valleys in and around the Cairngorm Granite pluton were examined on satellite and aerial photographs and by field survey. Topographic lineaments, including valleys, show no consistent orientation with joint sets or with sheets of microgranite and pegmatitic granite. In this granite landscape, jointing is not a first-order control on valley development. Instead, glens and headwater valleys align closely to quartz veins and linear alteration zones (LAZs). LAZs are zones of weakness in the granite pluton in which late-stage hydrothermal alteration and hydro-fracturing have greatly reduced rock mass strength and increased permeability. LAZs, which can be kilometres long and >700 m deep, are the dominant controls on the orientation of valleys in the Cairngorms. LAZs formed in the roof zone of the granite intrusion. Although the Cairngorm pluton was unroofed soon after emplacement, the presence of Old Red Sandstone (ORS) outliers in the terrain to the north and east indicates that the lower relief of the sub-ORS basement surface has been lowered by <500 m. Hence, the valley patterns in and around the Cairngorms have persisted through >1 km of vertical erosion and for 400 Myr. This valley persistence is a combined product of regionally low rates of basement exhumation and of the existence of LAZs in the Cairngorm pluton and sub-parallel Caledonide fractures in the surrounding terrain with depths that exceed 1 km.

Hydraulic Fracturing Treatment Controls on Induced Microseismicity Attributes

NASA Astrophysics Data System (ADS)

Reyes-Montes, J. M.; Kelly, C.; Huang, J.; Zhao, X.; Young, R. P.

2014-12-01

Hydraulic fracturing imposes stress changes in the treated rock through the injection of a mix of fluid and proppant at variable rates and can result in stimulated microseismicity (induced or triggered) with a wide range of magnitudes associated to the opening of new cracks or the mobilisation of pre-existing fractures. Optimizing the treatment is vital for the economic and sustainable development of hydrocarbon reservoir and for the minimization of potential environmental impacts. The analysis of the induced seismicity and of event parameters provide an estimate of the effect of the treatment and the extent of the changes in the rock reservoir properties affecting fluid conductivity. This gives critical feedback for the optimization of the treatment, especially during real-time monitoring. In this study, we correlate microseismic attributes such as the fracture dimensions, event distribution and b-values with the fluid treatment parameters such as the pumping pressure and the slurry rate across different reservoir treatments. Although the microseismic attributes are influenced by many different factors such as the reservoir elastic properties, the stress regime and in-situ fracturing, we consistently observed positive correlations between the slurry rate, plateau treatment pressure and the fracture dimensions. In addition, the variation and systematic deviation of b-value from the natural average of 1.0 gives an insight into the geomechanical behavior of the reservoir. Similar to b-value, another fractal dimension, D-value, indicates the fracture spatial propagation from linear advancement (D=1.0) to planar distribution (D=2.0) to full space occurrence (D=3.0). By merging microseismic events from multiple treatment stages, we statistically analyzed magnitude distribution and spatial and temporal structure of the microseismic cloud induced during the stimulation of a range of different reservoirs with a total population of ~20,000 MS events. Analysis on multiple

Seismic Characterizations of Fractures: Dynamic Diagnostics

NASA Astrophysics Data System (ADS)

Pyrak-Nolte, L. J.

2017-12-01

Fracture geometry controls fluid flow in a fracture, affects mechanical stability and influences energy partitioning that affects wave scattering. Our ability to detect and monitor fracture evolution is controlled by the frequency of the signal used to probe a fracture system, i.e. frequency selects the scales. No matter the frequency chosen, some set of discontinuities will be optimal for detection because different wavelengths sample different subsets of fractures. The select subset of fractures is based on the stiffness of the fractures which in turn is linked to fluid flow. A goal is obtaining information from scales outside the optimal detection regime. Fracture geometry trajectories are a potential approach to drive a fracture system across observation scales, i.e. moving systems between effective medium and scattering regimes. Dynamic trajectories (such as perturbing stress, fluid pressure, chemical alteration, etc.) can be used to perturb fracture geometry to enhance scattering or give rise to discrete modes that are intimately related to the micro-structural evolution of a fracture. However, identification of these signal features will require methods for identifying these micro-structural signatures in complicated scattered fields. Acknowledgment: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Geosciences Research Program under Award Number (DE-FG02-09ER16022).

Serum vitamin E concentrations among highly functioning hip fracture patients are higher than in nonfracture controls.

PubMed

D'Adamo, Christopher R; Shardell, Michelle D; Hicks, Gregory E; Orwig, Denise L; Hochberg, Marc C; Semba, Richard D; Yu-Yahiro, Janet A; Ferrucci, Luigi; Magaziner, Jay S; Miller, Ram R

2011-03-01

Malnutrition after hip fracture is common and associated with poor outcomes and protracted recovery. Low concentrations of vitamin E have been associated with incident decline in physical function among older adults and may, therefore, be particularly important to functionally compromised patients hip fracture patients. Serum concentrations of α-tocopherol and γ-tocopherol, the 2 major forms of vitamin E, were assessed in 148 female hip fracture patients 65 years or older from the Baltimore Hip Studies cohort 4 around the time of fracture (baseline) and at 2, 6, and 12 month postfracture follow-up visits (recovery). It was hypothesized that mean concentrations of both forms of vitamin E among these hip fracture patients would be lowest at the baseline visit and increase at each study visit during the year after fracture. Linear regression and generalized estimating equations were used to assess changes in vitamin E concentrations after adjustment for covariates and to determine predictors of vitamin E concentrations at baseline and throughout recovery. It was also hypothesized that vitamin E concentrations shortly after hip fracture would be lower than those in nonfracture controls after adjustment for covariates. To evaluate this hypothesis, linear regression was used to perform adjusted comparisons of baseline vitamin E concentrations among Baltimore Hip Studies cohort 4 participants to 1076 older women without history of hip fracture from the Women's Health and Aging Study I, Invecchiare in Chianti Study, and the National Health and Nutrition Examination Surveys. Mean α-tocopherol was lowest at baseline, and time from fracture to blood draw was positively associated with baseline α-tocopherol (P = .005). Mean γ-tocopherol did not change appreciably throughout the year after fracture, although it fluctuated widely within individuals. Serum concentrations of α-tocopherol and γ-tocopherol were highest among the hip fracture population after adjustment (P

Double Cantilever Beam Fracture Toughness Testing of Several Composite Materials

NASA Technical Reports Server (NTRS)

Kessler, Jeff A.; Adams, Donald F.

1992-01-01

Double-cantilever beam fracture toughness tests were performed by the Composite Materials Research Group on several different unidirectional composite materials provided by NASA Langley Research Center. The composite materials consisted of Hercules IM-7 carbon fiber and various matrix resin formulations. Multiple formulations of four different families of matrix resins were tested: LaRC - ITPI, LaRC - IA, RPT46T, and RP67/RP55. Report presents the materials tested and pertinent details supplied by NASA. For each material, three replicate specimens were tested. Multiple crack extensions were performed on each replicate.

[The randomized controlled trial of the treatment for clavicular fracture by rotatory manual reduction with forceps holder and retrograde percutaneous pinning transfixation].

PubMed

Bi, Hong-zheng; Yang, Mao-qing; Tan, Yuan-chao; Fu, Song

2008-07-01

To study the curative effect and safety of rotatory manual reduction with forceps holder and retrograde percutaneous pinning transfixation in treating clavicular fracture. All 201 cases of clavicular fractures were randomly divided into treatment group (101 cases) and control group (100 cases). The treatment group was treated by rotatory manual reduction with forceps holder and retrograde percutaneous pinning transfixation. The control group was treated by open reduction and internal fixation with Kirschner pin. All cases were followed up for 4 to 21 months (mean 10.6 months). SPSS was used to analyze clinic healing time of fracture and shoulder-joint function in both two groups. After operation, 101 cases of treatment group achieved union of fracture and the clinical healing time was 28 to 49 days (mean 34.5+/-2.7 days). In control group,there were 4 cases with nonunion of fracture,the other 96 cases were union,the clinical healing time was 36 to 92 days (mean 55.3+/-4.8 days). The excellent and good rate of shoulder-joint function was 100% in treatment group and 83% in control group. By t-test and chi2-test, there was significant difference between the two groups in curative effect (P<0.05). Rotatory manual reduction with forceps holder and retrograde pinning transfixation can be used in various kinds of clavicular shaft fracture, with many virtues such as easy operation, reliable fixation, short union time of fracture, good functional recovery of shoulder-joint and no incision scar affecting appearance.

External fixation of tibial pilon fractures and fracture healing.

PubMed

Ristiniemi, Jukka

2007-06-01

Distal tibial fractures are rare and difficult to treat because the bones are subcutaneous. External fixation is commonly used, but the method often results in delayed union. The aim of the present study was to find out the factors that affect fracture union in tibial pilon fractures. For this purpose, prospective data collection of tibial pilon fractures was carried out in 1998-2004, resulting in 159 fractures, of which 83 were treated with external fixation. Additionally, 23 open tibial fractures with significant > 3 cm bone defect that were treated with a staged method in 2000-2004 were retrospectively evaluated. The specific questions to be answered were: What are the risk factors for delayed union associated with two-ring hybrid external fixation? Does human recombinant BMP-7 accelerate healing? What is the role of temporary ankle-spanning external fixation? What is the healing potential of distal tibial bone loss treated with a staged method using antibiotic beads and subsequent autogenous cancellous grafting compared to other locations of the tibia? The following risk factors for delayed healing after external fixation were identified: post-reduction fracture gap of >3 mm and fixation of the associated fibula fracture. Fracture displacement could be better controlled with initial temporary external fixation than with early definitive fixation, but it had no significant effect on healing time, functional outcome or complication rate. Osteoinduction with rhBMP-7 was found to accelerate fracture healing and to shorten the sick leave. A staged method using antibiotic beads and subsequent autogenous cancellous grafting proved to be effective in the treatment of tibial bone loss. Healing potential of the bone loss in distal tibia was at least equally good as in other locations of the tibia.

Hip fracture risk in relation to vitamin D supplementation and serum 25-hydroxyvitamin D levels: a systematic review and meta-analysis of randomised controlled trials and observational studies

PubMed Central

2010-01-01

Background Vitamin D supplementation for fracture prevention is widespread despite conflicting interpretation of relevant randomised controlled trial (RCT) evidence. This study summarises quantitatively the current evidence from RCTs and observational studies regarding vitamin D, parathyroid hormone (PTH) and hip fracture risk. Methods We undertook separate meta-analyses of RCTs examining vitamin D supplementation and hip fracture, and observational studies of serum vitamin D status (25-hydroxyvitamin D (25(OH)D) level), PTH and hip fracture. Results from RCTs were combined using the reported hazard ratios/relative risks (RR). Results from case-control studies were combined using the ratio of 25(OH)D and PTH measurements of hip fracture cases compared with controls. Original published studies of vitamin D, PTH and hip fracture were identified through PubMed and Web of Science databases, searches of reference lists and forward citations of key papers. Results The seven eligible RCTs identified showed no significant difference in hip fracture risk in those randomised to cholecalciferol or ergocalciferol supplementation versus placebo/control (RR = 1.13[95%CI 0.98-1.29]; 801 cases), with no significant difference between trials of <800 IU/day and ≥800 IU/day. The 17 identified case-control studies found 33% lower serum 25(OH)D levels in cases compared to controls, based on 1903 cases. This difference was significantly greater in studies with population-based compared to hospital-based controls (χ21 (heterogeneity) = 51.02, p < 0.001) and significant heterogeneity was present overall (χ216 (heterogeneity) = 137.9, p < 0.001). Serum PTH levels in hip fracture cases did not differ significantly from controls, based on ten case-control studies with 905 cases (χ29 (heterogeneity) = 149.68, p < 0.001). Conclusions Neither higher nor lower dose vitamin D supplementation prevented hip fracture. Randomised and observational data on vitamin D and hip fracture appear to

NASA Dryden Status

NASA Technical Reports Server (NTRS)

Jacobson, Steve R.

2009-01-01

This slide presentation reviews several projects that NASA Dryden personnel are involved with: Integrated Resilient Aircraft Controls Project (IRAC), NASA G-III Research Aircraft, X-48B Blended Wing Body aircraft, Stratospheric Observatory for Infrared Astronomy (SOFIA), and the Orion CEV Launch Abort Systems Tests.

Thoracic kyphosis and rate of incident vertebral fractures: the Fracture Intervention Trial.

PubMed

Katzman, W B; Vittinghoff, E; Kado, D M; Lane, N E; Ensrud, K E; Shipp, K

2016-03-01

Biomechanical analyses support the theory that thoracic spine hyperkyphosis may increase risk of new vertebral fractures. While greater kyphosis was associated with an increased rate of incident vertebral fractures, our analysis does not show an independent association of kyphosis on incident fracture, after adjustment for prevalent vertebral fracture. Excessive kyphosis may still be a clinical marker for prevalent vertebral fracture. Biomechanical analyses suggest hyperkyphosis may increase risk of incident vertebral fracture by increasing the load on vertebral bodies during daily activities. We propose to assess the association of kyphosis with incident radiographic vertebral fracture. We used data from the Fracture Intervention Trial among 3038 women 55-81 years of age with low bone mineral density (BMD). Baseline kyphosis angle was measured using a Debrunner kyphometer. Vertebral fractures were assessed at baseline and follow-up from lateral radiographs of the thoracic and lumbar spine. We used Poisson models to estimate the independent association of kyphosis with incident fracture, controlling for age and femoral neck BMD. Mean baseline kyphosis was 48° (SD = 12) (range 7-83). At baseline, 962 (32%) participants had a prevalent fracture. There were 221 incident fractures over a median of 4 years. At baseline, prevalent fracture was associated with 3.7° greater average kyphosis (95% CI 2.8-4.6, p < 0.0005), adjusting for age and femoral neck BMD. Before adjusting for prevalent fracture, each 10° greater kyphosis was associated with 22% increase (95% CI 8-38%, p = 0.001) in annualized rate of new radiographic vertebral fracture, adjusting for age and femoral neck BMD. After additional adjustment for prevalent fracture, estimated increased annualized rate was attenuated and no longer significant, 8% per 10° kyphosis (95% CI -4 to 22%, p = 0.18). While greater kyphosis increased the rate of incident vertebral fractures, our analysis does not

Thoracic kyphosis and rate of incident vertebral fractures: the Fracture Intervention Trial

PubMed Central

Vittinghoff, E.; Kado, D. M.; Lane, N. E.; Ensrud, K. E.; Shipp, K.

2016-01-01

Summary Biomechanical analyses support the theory that thoracic spine hyperkyphosis may increase risk of new vertebral fractures. While greater kyphosis was associated with an increased rate of incident vertebral fractures, our analysis does not show an independent association of kyphosis on incident fracture, after adjustment for prevalent vertebral fracture. Excessive kyphosis may still be a clinical marker for prevalent vertebral fracture. Introduction Biomechanical analyses suggest hyperkyphosis may increase risk of incident vertebral fracture by increasing the load on vertebral bodies during daily activities. We propose to assess the association of kyphosis with incident radiographic vertebral fracture. Methods We used data from the Fracture Intervention Trial among 3038 women 55–81 years of age with low bone mineral density (BMD). Baseline kyphosis angle was measured using a Debrunner kyphometer. Vertebral fractures were assessed at baseline and follow-up from lateral radiographs of the thoracic and lumbar spine. We used Poisson models to estimate the independent association of kyphosis with incident fracture, controlling for age and femoral neck BMD. Results Mean baseline kyphosis was 48° (SD = 12) (range 7–83). At baseline, 962 (32 %) participants had a prevalent fracture. There were 221 incident fractures over a median of 4 years. At baseline, prevalent fracture was associated with 3.7° greater average kyphosis (95 % CI 2.8–4.6, p < 0.0005), adjusting for age and femoral neck BMD. Before adjusting for prevalent fracture, each 10° greater kyphosis was associated with 22 % increase (95 % CI 8–38 %, p = 0.001) in annualized rate of new radiographic vertebral fracture, adjusting for age and femoral neck BMD. After additional adjustment for prevalent fracture, estimated increased annualized rate was attenuated and no longer significant, 8 % per 10° kyphosis (95 % CI −4 to 22 %, p = 0.18). Conclusions While greater kyphosis increased the rate of

Flow Control Research at NASA Langley in Support of High-Lift Augmentation

NASA Technical Reports Server (NTRS)

Sellers, William L., III; Jones, Gregory S.; Moore, Mark D.

2002-01-01

The paper describes the efforts at NASA Langley to apply active and passive flow control techniques for improved high-lift systems, and advanced vehicle concepts utilizing powered high-lift techniques. The development of simplified high-lift systems utilizing active flow control is shown to provide significant weight and drag reduction benefits based on system studies. Active flow control that focuses on separation, and the development of advanced circulation control wings (CCW) utilizing unsteady excitation techniques will be discussed. The advanced CCW airfoils can provide multifunctional controls throughout the flight envelope. Computational and experimental data are shown to illustrate the benefits and issues with implementation of the technology.

Pulsed Electromagnetic Fields in the treatment of fresh scaphoid fractures. A multicenter, prospective, double blind, placebo controlled, randomized trial

PubMed Central

2011-01-01

Background The scaphoid bone is the most commonly fractured of the carpal bones. In the Netherlands 90% of all carpal fractures is a fracture of the scaphoid bone. The scaphoid has an essential role in functionality of the wrist, acting as a pivot. Complications in healing can result in poor functional outcome. The scaphoid fracture is a troublesome fracture and failure of treatment can result in avascular necrosis (up to 40%), non-union (5-21%) and early osteo-arthritis (up to 32%) which may seriously impair wrist function. Impaired consolidation of scaphoid fractures results in longer immobilization and more days lost at work with significant psychosocial and financial consequences. Initially Pulsed Electromagnetic Fields was used in the treatment of tibial pseudoarthrosis and non-union. More recently there is evidence that physical forces can also be used in the treatment of fresh fractures, showing accelerated healing by 30% and 71% reduction in nonunion within 12 weeks after initiation of therapy. Until now no double blind randomized, placebo controlled trial has been conducted to investigate the effect of this treatment on the healing of fresh fractures of the scaphoid. Methods/Design This is a multi center, prospective, double blind, placebo controlled, randomized trial. Study population consists of all patients with unilateral acute scaphoid fracture. Pregnant women, patients having a life supporting implanted electronic device, patients with additional fractures of wrist, carpal or metacarpal bones and pre-existing impairment in wrist function are excluded. The scaphoid fracture is diagnosed by a combination of physical and radiographic examination (CT-scanning). Proven scaphoid fractures are treated with cast immobilization and a small Pulsed Electromagnetic Fields bone growth stimulating device placed on the cast. Half of the devices will be disabled at random in the factory. Study parameters are clinical consolidation, radiological consolidation

Determination of Fracture Patterns in Glass and Glassy Polymers.

PubMed

Baca, Allison C; Thornton, John I; Tulleners, Frederic A

2016-01-01

The study of fractures of glass, glassy-type materials, and plastic has long been of interest to the forensic community. The focus of this interest has been the use of glass and polymer fractures to associate items of evidence under the assumption that each fracture is different. Generally, it is well-accepted that deviations exist; however, the emphasis has been on classifying and predicting fracture rather than determining that each fracture is different. This study documented the controlled fracture patterns of 60 glass panes, 60 glass bottles, and 60 plastic tail light lens covers using both dynamic impact and static pressure methods under closely controlled conditions. Each pattern was intercompared, and based on the limited specimens tested in this study, the results illustrate that the fracture patterns are different. Further repetitive studies, under controlled conditions, will be needed to provide more statistical significance to the theory that each fracture forms a nonreproducible fracture pattern. © 2015 American Academy of Forensic Sciences.

Fracture density and grain size controls on the relief structure of threshold landscapes

NASA Astrophysics Data System (ADS)

DiBiase, R.; Rossi, M. W.; Neely, A.

2015-12-01

A central goal in geomorphology is to untangle the competing controls of climate, tectonics, and rock strength on the topography and relief structure of mountain ranges. This is important for deciphering the history of climate and tectonics encoded in landscapes, predicting natural hazards, and quantifying critical zone processes. Incorporating rock strength into landscape evolution models has been a particularly challenging problem, because the factors that determine rock strength vary in importance depending on process. Here we propose a mechanism of hillslope-channel coupling by which tectonically-induced fracturing influences the relief structure of steep, rocky "threshold" landscapes by leading to A) increased fracture density in exposed bedrock outcrops, thereby limiting hillslope relief, and B) decreased grain size of channel bed material, thereby reducing the magnitude of fluvial incision thresholds and increasing the erosional efficiency of bedrock rivers. To test this hypothesis, we compare two contrasting landscapes in southern California—the eastern San Gabriel Mountains and the northern San Jacinto Mountains. The eastern San Gabriel Mountains rise 2 km in relief and exhibit high uplift and erosion rates due to active faulting along the Cucamonga thrust fault. Although bedrock on hillslopes is common, the exposed granitic and metamorphic basement rock is highly fractured at the decimeter or finer scale, and river channels are mantled with a thin layer of gravel-cobble alluvium. The northern San Jacinto Mountains, 80 km to the southeast, experience similar mean runoff and daily runoff variability, and are underlain by similar bedrock. Yet, despite an absence of active faulting, and erosion rates slower than the eastern San Gabriel Mountains by a factor of 5, the northern San Jacinto Mountains preserve one of the steepest escarpments in the contiguous US (2-3 km high), characterized by massive bedrock outcrops on hillslopes with meter-scale or larger

The impact of in-situ stress and outcrop-based fracture geometry on hydraulic aperture and upscaled permeability in fractured reservoirs

NASA Astrophysics Data System (ADS)

Bisdom, Kevin; Bertotti, Giovanni; Nick, Hamidreza M.

2016-10-01

Aperture has a controlling impact on porosity and permeability and is a source of uncertainty in modeling of naturally fractured reservoirs. This uncertainty results from difficulties in accurately quantifying aperture in the subsurface and from a limited fundamental understanding of the mechanical and diagenetic processes that control aperture. In the absence of cement bridges and high pore pressure, fractures in the subsurface are generally considered to be closed. However, experimental work, outcrop analyses and subsurface data show that some fractures remain open, and that aperture varies even along a single fracture. However, most fracture flow models consider constant apertures for fractures. We create a stress-dependent heterogeneous aperture by combining Finite Element modeling of discrete fracture networks with an empirical aperture model. Using a modeling approach that considers fractures explicitly, we quantify equivalent permeability, i.e. combined matrix and stress-dependent fracture flow. Fracture networks extracted from a large outcropping pavement form the basis of these models. The results show that the angle between fracture strike and σ1 has a controlling impact on aperture and permeability, where hydraulic opening is maximum for an angle of 15°. At this angle, the fracture experiences a minor amount of shear displacement that allows the fracture to remain open even when fluid pressure is lower than the local normal stress. Averaging the heterogeneous aperture to scale up permeability probably results in an underestimation of flow, indicating the need to incorporate full aperture distributions rather than simplified aperture models in reservoir-scale flow models.

Antipsychotic treatment and the risk of hip fracture in subjects with schizophrenia: a 10-year population-based case-control study.

PubMed

Wu, Chi-Shin; Chang, Chia-Ming; Tsai, Yu-Ting; Huang, Ya-Wen; Tsai, Hui-Ju

2015-09-01

To investigate the association between antipsychotic treatment and risk of hip fracture in subjects with schizophrenia. Among patients with schizophrenia (ICD-9-CM code 295), 605 cases with hip fracture and 2,828 matched controls were identified from 2002 to 2011 using the National Health Insurance Research Database in Taiwan. The authors conducted a nested case-control study to investigate the association between antipsychotic treatment and risk of hip fracture in subjects with schizophrenia. The modifiable effects of age and gender were evaluated by stratified analysis. In addition, the effects of antipsychotic use, antipsychotic classes, and receptor-binding profiles of antipsychotics, individually, on hip fracture were estimated, and potential confounding factors were adjusted in subsequent analysis. Conditional logistic regressions were applied to determine the effect of antipsychotic treatment on hip fracture. Current antipsychotic use was associated with an increased risk for hip fracture (adjusted odds ratio [AOR] = 1.61; 95% CI, 1.24-2.10). Among current users, new users had a higher risk of hip fracture (AOR = 4.28; 95% CI, 1.76-10.36) than past users (AOR = 1.11; 95% CI, 0.79-1.56). In addition, a significant increased risk of hip fracture was noted in schizophrenia subjects with first-generation antipsychotic use (AOR = 1.59; 95%CI, 1.15-2.20) but not in those with second-generation antipsychotic use (AOR = 1.16; 95% CI, 0.91-1.48). These results extend previous findings and demonstrate an increased risk of hip fracture associated with antipsychotic use in schizophrenia subjects. Further investigation is needed to dissect the underlying mechanisms related to the effect of antipsychotic use on hip fracture in subjects at risk. © Copyright 2015 Physicians Postgraduate Press, Inc.

[Treatment of posterior cruciate ligament avulsion fracture with rivet-assisted hollow nail:a case-control study].

PubMed

Zhu, Jia-Fu; Ma, Gou-Ping; Xu, Wei-Xing; Guo, Qiao-Feng; Liu, Hong

2017-04-25

To retrospectively investigate the clinical effect of the rivet-assisted hollow screw in the treatment of posterior cruciate ligament avulsion fracture. Total 49 patients with knee cruciate ligament avulsion fracture in the ending point of the ligament from January 2010 to December 2014 were divided into the treatment group and the control group. Thirty-one patients in treatment group were treated with rivet-assisted double cannulate nail, including 13 males and 18 females, ranging in age from 38 to 51 years old, with a mean of (40.6±5.1) years old; according to Meyers classification, 23 cases of type 2, 8 cases of type 3; 5 patients were caused by the low energy injury and 26 patients were caused by the high energy injury. Eighteen patients in control group were treated with double gold hollow screw fixation, including 5 males and 13 females, ranging in age from 36 to 52 years old, with an average age of (4.16±4.7) years old; according to Meyers classification, 14 cases of type 2 and 4 cases of type 3;2 patients were caused by the low energy injury and 16 patients were caused by the high energy injury. The operation time, postoperative complications, fracture healing time and the last AKS scoring system were compared between the two groups. All the patients were followed up, and the duration ranged from 12 to 24 months, with an average of 14.2 months. The patients in treatment group had no displacement of fracture fragments and internal fixation failure. The results of AKS score:pain was 48.1±1.5, activity was 21.3±2.7, stability was 20.9±2.5, walking ability was 47.3±1.9, under the stairs ability was 43.4±2.1, the total score was 190.7±2.9. There were 2 cases in control group had fracture fragment displacement and 1 patient had nail withdraw. The results of AKS score:pain was 40.1±2.2, activity was 20.1±0.2, stability was 18.1±3.2, walking ability was 46.3±1.7, under the stairs ability was 40.2 ±1.3, the total score was 180.2±1.4. Therefore, the

Fluid-driven fracture propagation in heterogeneous media: Probability distributions of fracture trajectories

NASA Astrophysics Data System (ADS)

Santillán, David; Mosquera, Juan-Carlos; Cueto-Felgueroso, Luis

2017-11-01

Hydraulic fracture trajectories in rocks and other materials are highly affected by spatial heterogeneity in their mechanical properties. Understanding the complexity and structure of fluid-driven fractures and their deviation from the predictions of homogenized theories is a practical problem in engineering and geoscience. We conduct a Monte Carlo simulation study to characterize the influence of heterogeneous mechanical properties on the trajectories of hydraulic fractures propagating in elastic media. We generate a large number of random fields of mechanical properties and simulate pressure-driven fracture propagation using a phase-field model. We model the mechanical response of the material as that of an elastic isotropic material with heterogeneous Young modulus and Griffith energy release rate, assuming that fractures propagate in the toughness-dominated regime. Our study shows that the variance and the spatial covariance of the mechanical properties are controlling factors in the tortuousness of the fracture paths. We characterize the deviation of fracture paths from the homogenous case statistically, and conclude that the maximum deviation grows linearly with the distance from the injection point. Additionally, fracture path deviations seem to be normally distributed, suggesting that fracture propagation in the toughness-dominated regime may be described as a random walk.

Fluid-driven fracture propagation in heterogeneous media: Probability distributions of fracture trajectories.

PubMed

Santillán, David; Mosquera, Juan-Carlos; Cueto-Felgueroso, Luis

2017-11-01

Hydraulic fracture trajectories in rocks and other materials are highly affected by spatial heterogeneity in their mechanical properties. Understanding the complexity and structure of fluid-driven fractures and their deviation from the predictions of homogenized theories is a practical problem in engineering and geoscience. We conduct a Monte Carlo simulation study to characterize the influence of heterogeneous mechanical properties on the trajectories of hydraulic fractures propagating in elastic media. We generate a large number of random fields of mechanical properties and simulate pressure-driven fracture propagation using a phase-field model. We model the mechanical response of the material as that of an elastic isotropic material with heterogeneous Young modulus and Griffith energy release rate, assuming that fractures propagate in the toughness-dominated regime. Our study shows that the variance and the spatial covariance of the mechanical properties are controlling factors in the tortuousness of the fracture paths. We characterize the deviation of fracture paths from the homogenous case statistically, and conclude that the maximum deviation grows linearly with the distance from the injection point. Additionally, fracture path deviations seem to be normally distributed, suggesting that fracture propagation in the toughness-dominated regime may be described as a random walk.

Linear elastic fracture mechanics primer

NASA Technical Reports Server (NTRS)

Wilson, Christopher D.

1992-01-01

This primer is intended to remove the blackbox perception of fracture mechanics computer software by structural engineers. The fundamental concepts of linear elastic fracture mechanics are presented with emphasis on the practical application of fracture mechanics to real problems. Numerous rules of thumb are provided. Recommended texts for additional reading, and a discussion of the significance of fracture mechanics in structural design are given. Griffith's criterion for crack extension, Irwin's elastic stress field near the crack tip, and the influence of small-scale plasticity are discussed. Common stress intensities factor solutions and methods for determining them are included. Fracture toughness and subcritical crack growth are discussed. The application of fracture mechanics to damage tolerance and fracture control is discussed. Several example problems and a practice set of problems are given.

Control of large flexible structures - An experiment on the NASA Mini-Mast facility

NASA Technical Reports Server (NTRS)

Hsieh, Chen; Kim, Jae H.; Liu, Ketao; Zhu, Guoming; Skelton, Robert E.

1991-01-01

The output variance constraint controller design procedure is integrated with model reduction by modal cost analysis. A procedure is given for tuning MIMO controller designs to find the maximal rms performance of the actual system. Controller designs based on a finite-element model of the system are compared with controller designs based on an identified model (obtained using the Q-Markov Cover algorithm). The identified model and the finite-element model led to similar closed-loop performance, when tested in the Mini-Mast facility at NASA Langley.

Fracture control of ground water flow and water chemistry in a rock aquitard.

PubMed

Eaton, Timothy T; Anderson, Mary P; Bradbury, Kenneth R

2007-01-01

There are few studies on the hydrogeology of sedimentary rock aquitards although they are important controls in regional ground water flow systems. We formulate and test a three-dimensional (3D) conceptual model of ground water flow and hydrochemistry in a fractured sedimentary rock aquitard to show that flow dynamics within the aquitard are more complex than previously believed. Similar conceptual models, based on regional observations and recently emerging principles of mechanical stratigraphy in heterogeneous sedimentary rocks, have previously been applied only to aquifers, but we show that they are potentially applicable to aquitards. The major elements of this conceptual model, which is based on detailed information from two sites in the Maquoketa Formation in southeastern Wisconsin, include orders of magnitude contrast between hydraulic diffusivity (K/S(s)) of fractured zones and relatively intact aquitard rock matrix, laterally extensive bedding-plane fracture zones extending over distances of over 10 km, very low vertical hydraulic conductivity of thick shale-rich intervals of the aquitard, and a vertical hydraulic head profile controlled by a lateral boundary at the aquitard subcrop, where numerous surface water bodies dominate the shallow aquifer system. Results from a 3D numerical flow model based on this conceptual model are consistent with field observations, which did not fit the typical conceptual model of strictly vertical flow through an aquitard. The 3D flow through an aquitard has implications for predicting ground water flow and for planning and protecting water supplies.

Fracture control of ground water flow and water chemistry in a rock aquitard

USGS Publications Warehouse

Eaton, T.T.; Anderson, M.P.; Bradbury, K.R.

2007-01-01

There are few studies on the hydrogeology of sedimentary rock aquitards although they are important controls in regional ground water flow systems. We formulate and test a three-dimensional (3D) conceptual model of ground water flow and hydrochemistry in a fractured sedimentary rock aquitard to show that flow dynamics within the aquitard are more complex than previously believed. Similar conceptual models, based on regional observations and recently emerging principles of mechanical stratigraphy in heterogeneous sedimentary rocks, have previously been applied only to aquifers, but we show that they are potentially applicable to aquitards. The major elements of this conceptual model, which is based on detailed information from two sites in the Maquoketa Formation in southeastern Wisconsin, include orders of magnitude contrast between hydraulic diffusivity (K/Ss) of fractured zones and relatively intact aquitard rock matrix, laterally extensive bedding-plane fracture zones extending over distances of over 10 km, very low vertical hydraulic conductivity of thick shale-rich intervals of the aquitard, and a vertical hydraulic head profile controlled by a lateral boundary at the aquitard subcrop, where numerous surface water bodies dominate the shallow aquifer system. Results from a 3D numerical flow model based on this conceptual model are consistent with field observations, which did not fit the typical conceptual model of strictly vertical flow through an aquitard. The 3D flow through an aquitard has implications for predicting ground water flow and for planning and protecting water supplies. ?? 2007 National Ground Water Association.

Development of a quality control test procedure for characterizing fracture properties of asphalt mixtures.

DOT National Transportation Integrated Search

2011-06-01

The main objective of this study is to investigate the use of the semi-circular bend (SCB) : test as a quality assurance/quality control (QA/QC) measure for field construction. : Comparison of fracture properties from the SCB test and fatigue beam te...

Orbital fractures due to domestic violence: an epidemiologic study.

PubMed

Goldberg, Stuart H.; McRill, Connie M.; Bruno, Christopher R.; Ten Have, Tom; Lehman, Erik

2000-09-01

Domestic violence is an important cause of orbital fractures in women. Physicians who treat patients with orbital fractures may not suspect this mechanism of injury. The purpose of this study was to assess the association between domestic violence and orbital fractures. A medical center-based case-control study with matching on age and site of admission was done. Medical center databases were searched using ICD-9 codes to identify all cases of orbital fractures encountered during a three-year period. Medical records of female patients age 13 and older were reviewed along with those of age, gender and site of admission matched controls. A stratified exact test was employed to test the association between domestic violence and orbital fracture. Among 41 adult female cases with orbital fractures treated at our medical center, three (7.3%) reported domestic violence compared to zero among the matched controls (p = 0.037). We believe that domestic violence may be under-reported in both orbital fracture cases and controls. This may result in an underestimate of the orbital fracture versus domestic violence association. Domestic violence is a serious women's health and societal problem. Domestic violence may have a variety of presentations, including illnesses and injuries. Orbital fracture is an identifiable manifestation of domestic violence. Domestic violence is more likely to be detected in adult female hospital patients with orbital fracture than in matched controls with any other diagnosis. Physicians who treat patients with orbital fractures should be familiar with this mechanism of injury.

Fatigue and Fracture Branch: A compendium of recently completed and on-going research projects

NASA Technical Reports Server (NTRS)

Elber, W.

1984-01-01

This compendium of recently completed and ongoing research projects from the Fatigue and Fracture Branch at NASA Langley Research Center provides technical descriptions and key results of all such projects expected to lead to publication of significant findings. The common thread to all these studies is the application of fracture mechanics analyses to engineering problems in metals and composites, with particular emphasis on airframe structural materials. References to recent publications are included where appropriate.

Endeavour sitting atop NASA's Shuttle Carrier Aircraft (SCA)

NASA Image and Video Library

2012-09-19

Space Shuttle Endeavour is ferried by NASA's Shuttle Carrier Aircraft (SCA) over the Johnson Space Center in Houston, Texas on September 19, 2012. NASA pilots Jeff Moultrie and Bill Rieke are at the controls of the Shuttle Carrier Aircraft. Photo taken by NASA photographer Sheri Locke in the backseat of a NASA T-38 chase plane with NASA pilot Thomas E. Parent at the controls. Photo Credit: NASA/ Sheri Locke

Underground Injection Control, Hydraulic Fracturing, and Sources of Drinking Water in the Western United States

NASA Astrophysics Data System (ADS)

Jackson, R. B.; Kang, M.

2016-12-01

Oil and gas extraction is expanding in the United States, attributable to the success of high-volume hydraulic fracturing, and associated wastewater disposal is increasing as a result. The United States currently has approximately 180,000 Class II injection wells associated with the oil and gas industry, more than 50,000 of them in California. Hydraulic fracturing and underground injection often occur many thousands of feet belowground. Previously, however, we documented shallow hydraulic fracturing and other oil and gas activities across the western United States in particular, including California and Wyoming. In eight CA counties, for example, as many as 19% and 35% of oil/gas activities have occurred directly in freshwater zones and USDWs, respectively (Kang and Jackson 2016 PNAS). Here we expand this analysis to examine the underground injection control program and accompanying hydrogeologic variables found in California and elsewhere.

Fourier Transformed Infra-Red Imaging of Femoral Neck Bone: Reduced Heterogeneity of Mineral-to-Matrix and Carbonate-to-Phosphate and more Variable Crystallinity in Treatment-Naïve Fracture Cases compared to Fracture-Free Controls

PubMed Central

Gourion-Arsiquaud, Samuel; Lukashova, Lyudmilla; Power, Jon; Loveridge, Nigel; Reeve, Jonathan; Boskey, Adele L.

2012-01-01

After age 60 hip fracture risk strongly increases, but only a fifth of this increase is attributable to reduced mineral density (BMD, measured clinically). Changes in bone quality, specifically bone composition as measured by Fourier Transform Infrared spectroscopic imaging (FTIRI), also contribute to fracture risk. Here, FTIRI was applied to study the femoral neck and provide spatially derived information on its mineral and matrix properties in age-matched fractured and non-fractured bones. Whole femoral neck cross sections, divided into quadrants along the neck’s axis, from 10 women with hip fracture and 10 cadaveric controls were studied using FTIRI and micro-computed Tomography. Although 3-dimensional micro-CT bone mineral densities were similar, the mineral-to-matrix ratio was reduced in the cases of hip fracture, confirming previous reports. New findings were that the FTIRI microscopic variation (heterogeneity) of the mineral-to-matrix ratio was substantially reduced in the fracture group as was the heterogeneity of the carbonate-to-phosphate ratio. Conversely, the heterogeneity of crystallinity was increased. Increased variation of crystallinity was statistically associated with reduced variation of the carbonate-to-phosphate ratio. Anatomical variation in these properties between the different femoral neck quadrants was reduced in the fracture group compared to controls. While our treatment-naïve patients had reduced rather than increased bending resistance, these changes in heterogeneity associated with hip fracture are in another way comparable to the effects of experimental bisphosphonate therapy, which decreases heterogeneity and other indicators of bone’s toughness as a material. PMID:22865771

NASA Thesaurus Data File

NASA Technical Reports Server (NTRS)

2012-01-01

The NASA Thesaurus contains the authorized NASA subject terms used to index and retrieve materials in the NASA Aeronautics and Space Database (NA&SD) and NASA Technical Reports Server (NTRS). The scope of this controlled vocabulary includes not only aerospace engineering, but all supporting areas of engineering and physics, the natural space sciences (astronomy, astrophysics, planetary science), Earth sciences, and the biological sciences. The NASA Thesaurus Data File contains all valid terms and hierarchical relationships, USE references, and related terms in machine-readable form. The Data File is available in the following formats: RDF/SKOS, RDF/OWL, ZThes-1.0, and CSV/TXT.

A close examination of healthcare expenditures related to fractures.

PubMed

Kilgore, Meredith L; Curtis, Jeffrey R; Delzell, Elizabeth; Becker, David J; Arora, Tarun; Saag, Kenneth G; Morrisey, Michael A

2013-04-01

This study evaluated reasons for healthcare expenditures both before and after the occurrence of fractures among Medicare beneficiaries. In a previous study we examined healthcare expenditures in the 6 months before and after fractures. The difference-"incremental" expenditures-provides one estimate of the potentially avoidable costs associated with fractures. We constructed a second estimate of the cost burden-"attributable" expenditures-using only those costs recorded in claims with fracture diagnosis codes. Attributable expenditures accounted for only 24% to 60% of incremental expenditures, depending on the fracture site. We examined health care expenditures between 1999 and 2005 among Medicare beneficiaries who experienced fractures (cases) and among beneficiaries who did not experience fractures (controls), matched to cases on age, race, and sex. We also examined healthcare expenditures for cases and controls for 24 months prior to the fracture index date. When expenditures associated with diagnoses for aftercare, joint pain, and osteoporosis, other musculoskeletal diagnoses, pneumonia, and pressure ulcers were included, the proportion of incremental costs directly attributable to fracture care rose to 72% to 88%. Expenditures prior to fracture were higher for cases than controls, and the rate of increase accelerated over the 12 months prior to the hip fracture. Our findings confirm that the original incremental cost analysis constituted a satisfactory method for estimating avoidable costs associated with fractures. We also conclude that those with fractures had much higher and growing healthcare expenditures in the 12 months prior to the event, compared with age-, race-, and sex-matched controls. This suggests that patterns of healthcare services utilization may provide a means to improve fracture prediction rules. Copyright © 2013 American Society for Bone and Mineral Research.

The prevention of hip fracture with risedronate and ergocalciferol plus calcium supplementation in elderly women with Alzheimer disease: a randomized controlled trial.

PubMed

Sato, Yoshihiro; Kanoko, Tomohiro; Satoh, Kei; Iwamoto, Jun

A high incidence of fractures, particularly of the hip, represents an important problem in patients with Alzheimer disease (AD), who are prone to falls and have osteoporosis. We previously found that deficiency of 25-hydroxyvitamin D and compensatory hyperparathyroidism cause reduced bone mineral density in female patients with AD. We address the possibility that treatment with risedronate sodium and ergocalciferol plus calcium supplementation may reduce the incidence of nonvertebral fractures in elderly women with AD. A total of 500 elderly women with AD were randomly assigned to daily treatment with 2.5 mg of risedronate sodium or a placebo, combined with 1000 IU of ergocalciferol and 1200 mg of elementary calcium, and followed up for 18 months. At baseline, patients of both groups showed 25-hydroxyvitamin D deficiency with compensatory hyperparathyroidism. During the study period, bone mineral density in the risedronate group increased by 4.1% and decreased by 0.9% in the control group. Vertebral fractures occurred in 29 patients (24 hip fractures) in the control group and 8 patients (5 hip fractures) in the risedronate group. The relative risk in the risedronate group compared with the control group was 0.28 (95% confidence interval, 0.13-0.59). Elderly patients with AD hypovitaminosis D are at increased risk for hip fracture. Treatment with risedronate and ergocalciferol may be safe and effective in reducing the risk of a fracture in elderly patients with AD.

Spatial and layer-controlled variability in fracture networks

NASA Astrophysics Data System (ADS)

Procter, Andrew; Sanderson, David J.

2018-03-01

Topological sampling, based on 1) node counting and 2) circular sampling areas, is used to measure fracture intensity in surface exposures of a layered limestone/shale sequence in north Somerset, UK. This method provides similar levels of precision as more traditional line samples, but is about 10 times quicker and allows characterization of the network topology. Georeferencing of photographs of the sample sites allows later analysis of trace lengths and orientations, and identification of joint set development. ANOVA tests support a complex interaction of within-layer, between-layer and between-location variability in fracture intensity, with the different layers showing anomalous intensity at different locations. This variation is not simply due to bed thickness, nor can it be related to any obvious compositional or textural variation between the limestone beds. These results are used to assess approaches to the spatial mapping of fracture intensity.

COMplex Fracture Orthopedic Rehabilitation (COMFORT) - Real-time visual biofeedback on weight bearing versus standard training methods in the treatment of proximal femur fractures in the elderly: study protocol for a multicenter randomized controlled trial.

PubMed

Raaben, Marco; Redzwan, Syaiful; Augustine, Robin; Blokhuis, Taco Johan

2018-04-12

Proximal femur fractures are a common injury after low energy trauma in the elderly. Most rehabilitation programs are based on restoring mobility and early resumption of weight-bearing. However, therapy compliance is low in patients following lower extremity fractures. Moreover, little is known about the relevance of gait parameters and how to steer the rehabilitation after proximal femur fractures in the elderly. Therefore, the aim of this prospective, randomized controlled trial is to gain insight in gait parameters and evaluate if real-time visual biofeedback can improve therapy compliance after proximal femur fractures in the elderly. This is a two-arm, parallel-design, prospective, randomized controlled trial. Inclusion criteria are age ≥ 60 years, a proximal femur fracture following low energy trauma, and unrestricted-weight bearing. Exclusion criteria are cognitive impairment and limited mobility before trauma. Participants are randomized into either the control group, which receives care as usual, or the intervention group, which receives real-time visual biofeedback about weight-bearing during gait in addition to care as usual. Spatiotemporal gait parameters will be measured in 94 participants per group during a 30-m walk with an ambulatory biofeedback system (SensiStep). The progress of rehabilitation will be evaluated by the primary outcome parameters maximum peak load and step duration in relation to the discharge date. Secondary outcome parameters include other spatiotemporal gait parameters in relation to discharge date. Furthermore, the gait parameters will be related to three validated clinical tests: Elderly Mobility Scale; Functional Ambulation Categories; and Visual Analogue Scale. The primary hypothesis is that participants in the intervention group will show improved and faster rehabilitation compared to the control group. The first aim of this multicenter trial is to investigate the normal gait patterns after proximal femur fractures in

The radiographic trabecular pattern of hips in patients with hip fractures and in elderly control subjects.

PubMed

Geraets, W G; Van der Stelt, P F; Lips, P; Van Ginkel, F C

1998-02-01

Due to the increasing number of osteoporotic fractures of hip, spine, and wrist there is a growing need for methods to track down the subjects with inferior bone structure and to monitor the effects of therapeutic measures. This study aims at a noninvasive diagnostic tool, deriving architectural properties of trabecular bone from in vivo measurements on plane radiographic films. Pelvic radiographs of the nonfractured hips of 81 patients with hip fractures and of the right hips of 74 controls were studied. The regions of interest, 2 x 2 cm2, located in the femoral neck, were sampled and digitized with a video camera connected to an image analysis system. Several geometrical and directional measurements were made. The measurements were evaluated by statistical comparison with fracture risk, gender, and Singh index. By discriminant analysis, type of fracture, as well as gender and Singh index could be predicted correctly for 58% of the subjects, whereas guessing would be correct in only 8%. It was found that the geometrical parameters discriminate between hips of controls and patients. With respect to the directional measurements associations were found with gender and Singh index. Although the new parameters assess fracture risk less accurately than bone density measurements, some parameters suggest by their behavior that they are relevant with respect to femoral bone architecture and its mechanical behavior. Although interpretation of the measurements in histological concepts requires methods that have been reported in literature only recently, it is concluded that digital analysis of the radiographic trabecular pattern is an interesting option to increase the diagnostic yield of plane film radiographs and to study the structure of bone in vivo.

Vitamin D Status and the Relationship with Bone Fragility Fractures in HIV-Infected Patients: A Case Control Study.

PubMed

Atteritano, Marco; Mirarchi, Luigi; Venanzi-Rullo, Emmanuele; Santoro, Domenico; Iaria, Chiara; Catalano, Antonino; Lasco, Antonino; Arcoraci, Vincenzo; Lo Gullo, Alberto; Bitto, Alessandra; Squadrito, Francesco; Cascio, Antonio

2018-01-02

HIV-infected patients show high risk of fracture. The aims of our study were to determine the prevalence of vertebral fractures (VFs) and their associations with vitamin D in HIV patients. 100 patients with HIV infection and 100 healthy age- and sex-matched controls were studied. Bone mineral density was measured by quantitative ultrasound at the non-dominant heel. Serum osteocalcin and C-terminal telopeptide of collagen type 1 served as bone turnover markers. Bone ultrasound measurements were significantly lower in patients compared with controls (Stiffness Index (SI): 80.58 ± 19.95% vs. 93.80 ± 7.10%, respectively, p < 0.001). VFs were found in 16 patients and in 2 controls. HIV patients with vertebral fractures showed lower stiffness index (SI) (70.75 ± 10.63 vs. 83.36 ± 16.19, respectively, p = 0.045) and lower vitamin D levels (16.20 ± 5.62 vs. 28.14 ± 11.94, respectively, p < 0.02). The majority of VFs (87.5%) were observed in HIV-infected patients with vitamin D insufficiency, and regression analysis showed that vitamin D insufficiency was significantly associated with vertebral fractures (OR 9.15; 95% CI 0.18-0.52, p < 0.04). VFs and are a frequent occurrence in HIV-infected patients and may be associated with vitamin D insufficiency.

The shear band controlled deformation in metallic glass: a perspective from fracture

NASA Astrophysics Data System (ADS)

Yang, G. N.; Shao, Y.; Yao, K. F.

2016-02-01

Different from the homogenous deformation in conventional crystalline alloys, metallic glasses and other work-softening materials deform discontinuously by localized plastic strain in shear bands. Here by three-point bending test on a typical ductile Pd-Cu-Si metallic glass, we found that the plastic deformed region during fracture didn’t follow the yielding stress distribution as the conventional material mechanics expected. We speculated that such special behavior was because the shear bands in metallic glasses could propagate easily along local shear stress direction once nucleated. Based on a 3D notch tip stress field simulation, we considered a new fracture process in a framework of multiple shear band deformation mechanism instead of conventional materials mechanics, and successfully reproduced the as-observed complicate shear band morphologies. This work clarifies many common misunderstandings on metallic glasses fracture, and might also provide a new insight to the shear band controlled deformation. It suggests that the deformation of metallic glasses is sensitive to local stress condition, and therefore their mechanical properties would depend on not only the material, but also other external factors on stress condition. We hope that start from this work, new methods, criteria, or definitions could be proposed to further study these work-softening materials, especially for metallic glasses.

Propulsion Controls and Health Management Research at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Garg, Sanjay

2002-01-01

With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Technology Branch at NASA Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with the U.S. aerospace industry and academia to develop advanced controls and health management technologies that will help meet these challenges. These technologies are being developed with a view towards making the concept of "Intelligent Engines" a reality. The major research activities of the Controls and Dynamics Technology Branch are described in the following.

Fracture control methods for space vehicles. Volume 2: Assessment of fracture mechanics technology for space shuttle applications

NASA Technical Reports Server (NTRS)

Ehret, R. M.

1974-01-01

The concepts explored in a state of the art review of those engineering fracture mechanics considered most applicable to the space shuttle vehicle include fracture toughness, precritical flaw growth, failure mechanisms, inspection methods (including proof test logic), and crack growth predictive analysis techniques.

A Selection of Composites Simulation Practices at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Ratcliffe, James G.

2007-01-01

One of the major areas of study at NASA Langley Research Center is the development of technologies that support the use of advanced composite materials in aerospace applications. Amongst the supporting technologies are analysis tools used to simulate the behavior of these materials. This presentation will discuss a number of examples of analysis tools and simulation practices conducted at NASA Langley. The presentation will include examples of damage tolerance analyses for both interlaminar and intralaminar failure modes. Tools for modeling interlaminar failure modes include fracture mechanics and cohesive methods, whilst tools for modeling intralaminar failure involve the development of various progressive failure analyses. Other examples of analyses developed at NASA Langley include a thermo-mechanical model of an orthotropic material and the simulation of delamination growth in z-pin reinforced laminates.

The Integration of COTS/GOTS within NASA's HST Command and Control System

NASA Technical Reports Server (NTRS)

Pfarr, Thomas; Reis, James E.

2001-01-01

NASA's mission critical Hubble Space Telescope (HST) command and control system has been re-engineered with commercial-off-the-shelf (COTS/GOTS) and minimal custom code. This paper focuses on the design of this new HST Control Center System (CCS) and the lessons learned throughout its development. CCS currently utilizes more than 30 COTS/GOTS products with an additional 1/2 million lines of custom glueware code; the new CCS exceeds the capabilities of the original system while significantly reducing the lines of custom code by more than 50%. The lifecycle of COTS/GOTS products will be examined including the package selection process, evaluation process, and integration process. The advantages, disadvantages, issues, concerns, and lessons learned for integrating COTS/GOTS into the NASA's mission critical HST CCS will be examined in detail. This paper will reveal the many hidden costs of COTS/GOTS solutions when compared to traditional custom code development efforts; this paper will show the high cost of COTS/GOTS solutions including training expenses, consulting fees, and long-term maintenance expenses.

NASA B737 flight test results of the Total Energy Control System

NASA Technical Reports Server (NTRS)

Bruce, K. R.; Kelly, J. R.; Person, L. H., Jr.

1986-01-01

The Total Energy Control System was developed and tested in September 1985 during five flights on the NASA Langley Transport System Research Vehicle, a modified Boeing B737. In the system, the total kinetic and potential energy of the aircraft is controlled by the throttles, and the energy distribution is controlled by the elevator. A common inner loop is used for each mode of the autopilot, and all the control functions of a conventional pitch autopilot and autothrottle are integrated into a single generalized control concept, providing decoupled flightpath and maneuver control, and a coordinated throttle response for all maneuvers. No instabilities or design problems requiring gain adjustment in flight were found, and comparison with simulation results showed excellent path tracking.

Temperament and fracture in preschool-aged children.

PubMed

Ryckman, Kandace; Richmond, Sarah A; Anderson, Laura N; Birken, Catherine S; Parkin, Patricia C; Macarthur, Colin; Maguire, Jonathon L; Howard, Andrew W

2017-07-01

Approximately one-half of all children will sustain a fracture before adulthood. Understanding the factors that place a child at increased risk of fracture is necessary to inform effective injury prevention strategies. The purpose of this study was to examine the association between temperament and fracture risk in preschool-aged children. Children aged 3 to 6 years who were diagnosed with a fracture were recruited from the Hospital for Sick Children Fracture Clinic. Using a retrospective case-control study design, the 148 cases were frequency-matched by age and sex to 426 controls from the TARGet Kids primary care paediatric cohort. The Childhood Behaviour Questionnaire, a 36-item caregiver response questionnaire was used to assess three of the following temperament factors: surgency (e.g., high activity level), negative affect (e.g., anger, fear, discomfort) and effortful control (e.g., attentional focusing). Unadjusted logistic models demonstrated no association between children with previous fracture and higher scores of surgency (unadjusted odds ratio [OR]=1.06, 95% confidence interval [CI]: 0.84, 1.34), negative affect (unadjusted OR=1.15, 95% CI: 0.93, 1.42) or effortful control (unadjusted OR=0.80, 95% CI: 0.63, 1.03). Further, models adjusted for covariates also demonstrated no significant association with surgency (1.00, 95% CI: 0.78, 1.29), negative affect (1.09, 95% CI: 0.86, 1.37) and effortful control (0.80, 95% CI: 0.61, 1.05). None of the three main temperament types identified by the Childhood Behaviour Questionnaire were associated with an increase in fracture risk.

Publications of the NASA Controlled Ecological Life Support System (CELSS) Program, 1979-1989

NASA Technical Reports Server (NTRS)

Wallace, Janice S.; Powers, Janet V.

1990-01-01

Publications of research sponsored by the NASA Controlled Ecological Life Support System (CELSS) Program from 1979 to 1989 are listed. The CELSS Program encompasses research and technology with the goal of developing an autonomous bioregenerative life support system that continually recycles the solid, liquid, and gaseous materials essential for human life. The bibliography is divided into four major subject areas: food production, nutritional requirements, waste management, and systems management and control.

Pulsed Electromagnetic Fields in the treatment of fresh scaphoid fractures. A multicenter, prospective, double blind, placebo controlled, randomized trial.

PubMed

Hannemann, Pascal; Göttgens, Kevin W A; van Wely, Bob J; Kolkman, Karel A; Werre, Andries J; Poeze, Martijn; Brink, Peter R G

2011-05-06

The scaphoid bone is the most commonly fractured of the carpal bones. In the Netherlands 90% of all carpal fractures is a fracture of the scaphoid bone. The scaphoid has an essential role in functionality of the wrist, acting as a pivot. Complications in healing can result in poor functional outcome. The scaphoid fracture is a troublesome fracture and failure of treatment can result in avascular necrosis (up to 40%), non-union (5-21%) and early osteo-arthritis (up to 32%) which may seriously impair wrist function. Impaired consolidation of scaphoid fractures results in longer immobilization and more days lost at work with significant psychosocial and financial consequences.Initially Pulsed Electromagnetic Fields was used in the treatment of tibial pseudoarthrosis and non-union. More recently there is evidence that physical forces can also be used in the treatment of fresh fractures, showing accelerated healing by 30% and 71% reduction in nonunion within 12 weeks after initiation of therapy. Until now no double blind randomized, placebo controlled trial has been conducted to investigate the effect of this treatment on the healing of fresh fractures of the scaphoid. This is a multi center, prospective, double blind, placebo controlled, randomized trial. Study population consists of all patients with unilateral acute scaphoid fracture. Pregnant women, patients having a life supporting implanted electronic device, patients with additional fractures of wrist, carpal or metacarpal bones and pre-existing impairment in wrist function are excluded. The scaphoid fracture is diagnosed by a combination of physical and radiographic examination (CT-scanning).Proven scaphoid fractures are treated with cast immobilization and a small Pulsed Electromagnetic Fields bone growth stimulating device placed on the cast. Half of the devices will be disabled at random in the factory.Study parameters are clinical consolidation, radiological consolidation evaluated by CT-scanning, functional

Efficacy of popliteal block in postoperative pain control after ankle fracture fixation: a prospective randomized study.

PubMed

Goldstein, Rachel Y; Montero, Nicole; Jain, Sudheer K; Egol, Kenneth A; Tejwani, Nirmal C

2012-10-01

To compare postoperative pain control in patients treated surgically for ankle fractures who receive popliteal blocks with those who received general anesthesia alone. Institutional Review Board approved prospective randomized study. Metropolitan tertiary-care referral center. All patients being treated with open reduction internal fixation for ankle fractures who met inclusion criteria and consented to participate were enrolled. Patients were randomized to receive either general anesthesia (GETA) or intravenous sedation and popliteal block. Patients were assessed for duration of procedure, total time in the operating room, and postoperative pain at 2, 4, 8, 12, 24, and 48 hours after surgery using a visual analog scale. Fifty-one patients agreed to participate in the study. Twenty-five patients received popliteal block, while 26 patients received GETA. There were no anesthesia-related complications. At 2, 4, and 8 hours postoperatively, patients who underwent GETA demonstrated significantly higher pain. At 12 hours, there was no significant difference between the 2 groups with regard to pain control. However, by 24 hours, those who had received popliteal blocks had significantly higher pain with no difference by 48 hours. Popliteal block provides equivalent postoperative pain control to general anesthesia alone in patients undergoing operative fixation of ankle fractures. However, patients who receive popliteal blocks do experience a significant increase in pain between 12 and 24 hours. Recognition of this "rebound pain" with early narcotic administration may allow patients to have more effective postoperative pain control.

Free-Piston Stirling Convertor Controller Development at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Regan, Timothy

2004-01-01

The free-piston Stirling convertor end-to-end modeling effort at NASA Glenn Research Center (GRC) has produced a software-based test bed in which free-piston Stirling convertors can be simulated and evaluated. The simulation model includes all the components of the convertor - the Stirling cycle engine, linear alternator, controller, and load. This paper is concerned with controllers. It discusses three controllers that have been studied using this model. Case motion has been added to the model recently so that effects of differences between convertor components can be simulated and ameliorative control engineering techniques can be developed. One concern when applying a system comprised of interconnected mass-spring-damper components is to prevent operation in any but the intended mode. The design mode is the only desired mode of operation, but all other modes are considered in controller design.

Resilient Propulsion Control Research for the NASA Integrated Resilient Aircraft Control (IRAC) Project

NASA Technical Reports Server (NTRS)

Guo, Ten-Huei; Litt, Jonathan S.

2007-01-01

Gas turbine engines are designed to provide sufficient safety margins to guarantee robust operation with an exceptionally long life. However, engine performance requirements may be drastically altered during abnormal flight conditions or emergency maneuvers. In some situations, the conservative design of the engine control system may not be in the best interest of overall aircraft safety; it may be advantageous to "sacrifice" the engine to "save" the aircraft. Motivated by this opportunity, the NASA Aviation Safety Program is conducting resilient propulsion research aimed at developing adaptive engine control methodologies to operate the engine beyond the normal domain for emergency operations to maximize the possibility of safely landing the damaged aircraft. Previous research studies and field incident reports show that the propulsion system can be an effective tool to help control and eventually land a damaged aircraft. Building upon the flight-proven Propulsion Controlled Aircraft (PCA) experience, this area of research will focus on how engine control systems can improve aircraft safe-landing probabilities under adverse conditions. This paper describes the proposed research topics in Engine System Requirements, Engine Modeling and Simulation, Engine Enhancement Research, Operational Risk Analysis and Modeling, and Integrated Flight and Propulsion Controller Designs that support the overall goal.

Summary of NASA/DOE Aileron-Control Development Program for Wind Turbines

NASA Technical Reports Server (NTRS)

Miller, D. R.

1986-01-01

The development of aileron-control for wind turbines is discussed. Selected wind tunnel test results and full-scale rotor test results are presented for various types of ailerons. Finally, the current status of aileron-control development is discussed. Aileron-control was considered as a method of rotor control for use on wind turbines based on its potential to reduce rotor weight and cost. Following an initial feasibility study, a 20 percent chord aileron-control rotor was fabricated and tested on the NASA/DOE Mod-0 experimental wind turbine. Results from these tests indicated that the 20 percent chord ailerons regulated power and provided overspeed protection, but only over a very limited windspeed range. The next aileron-control rotor to be tested on the Mod-0 had 38 percent chord ailerons and test results showed these ailerons provided overspeed protection and power regulation over the Mod-0's entire operational windspeed range.

Requirements and feasibility study of flight demonstration of Active Controls Technology (ACT) on the NASA 515 airplane

NASA Technical Reports Server (NTRS)

Gordon, C. K.

1975-01-01

A preliminary design study was conducted to evaluate the suitability of the NASA 515 airplane as a flight demonstration vehicle, and to develop plans, schedules, and budget costs for fly-by-wire/active controls technology flight validation in the NASA 515 airplane. The preliminary design and planning were accomplished for two phases of flight validation.

Tight calorie control in geriatric patients following hip fracture decreases complications: a randomized, controlled study.

PubMed

Anbar, R; Beloosesky, Y; Cohen, J; Madar, Z; Weiss, A; Theilla, M; Koren Hakim, T; Frishman, S; Singer, P

2014-02-01

Optimizing nutritional intake has been recommended for geriatric patients undergoing hip-fracture surgery. Whether nutritional support guided by repeated measurements of resting energy requirements (REE) improves outcomes in these patients is not known. A randomized, controlled, unblinded, prospective, cohort study comparing provision of energy with a goal determined by repeated REE measurements using indirect calorimetry, with no intervention. Oral nutritional supplements were started 24 h after surgery and the amount adjusted to make up the difference between energy received from hospital food and measured energy expenditure. 50 Geriatric patients were included in the study. Patients in the intervention group (n = 22) received significantly higher daily energy intake than the control group (n = 28) (1121.3 ± 299.0 vs. 777.1 ± 301.2 kcal, p = 0.001). This was associated with a significantly less negative cumulative energy balance (-1229.9 ± 1763 vs. -4975.5 ± 4368 kcal, p = 0.001). A significant negative correlation was found between the cumulative energy balance and total complication rate (r = -0.417, p = 0.003) as well as for length of hospital stay (r = -0.282, p = 0.049). We have demonstrated that nutritional support actively supervised by a dietician and guided by repeated measurements of REE was achievable and improved outcomes in geriatric patients following surgery for hip fractures. Clinicaltrials.gov Identifier: NCT017354435. Copyright © 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Fracture Reactivation in Chemically Reactive Rock Systems

NASA Astrophysics Data System (ADS)

Eichhubl, P.; Hooker, J. N.

2013-12-01

Reactivation of existing fractures is a fundamental process of brittle failure that controls the nucleation of earthquake ruptures, propagation and linkage of hydraulic fractures in oil and gas production, and the evolution of fault and fracture networks and thus of fluid and heat transport in the upper crust. At depths below 2-3 km, and frequently shallower, brittle processes of fracture growth, linkage, and reactivation compete with chemical processes of fracture sealing by mineral precipitation, with precipitation rates similar to fracture opening rates. We recently found rates of fracture opening in tectonically quiescent settings of 10-20 μm/m.y., rates similar to euhedral quartz precipitation under these conditions. The tendency of existing partially or completely cemented fractures to reactivate will vary depending on strain rate, mineral precipitation kinetics, strength contrast between host rock and fracture cement, stress conditions, degree of fracture infill, and fracture network geometry. Natural fractures in quartzite of the Cambrian Eriboll Formation, NW Scotland, exhibit a complex history of fracture formation and reactivation, with reactivation involving both repeated crack-seal opening-mode failure and shear failure of fractures that formed in opening mode. Fractures are partially to completely sealed with crack-seal or euhedral quartz cement or quartz cement fragmented by shear reactivation. Degree of cementation controls the tendency of fractures for later shear reactivation, to interact elastically with adjacent open fractures, and their intersection behavior. Using kinematic, dynamic, and diagenetic criteria, we determine the sequence of opening-mode fracture formation and later shear reactivation. We find that sheared fracture systems of similar orientation display spatially varying sense of slip We attribute these inconsistent directions of shear reactivation to 1) a heterogeneous stress field in this highly fractured rock unit and 2

NASA Bioreactor

NASA Technical Reports Server (NTRS)

1996-01-01

Electronics control module for the NASA Bioreactor. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

Real-world antidiabetic drug use and fracture risk in 12,277 patients with type 2 diabetes mellitus: a nested case-control study.

PubMed

Losada, E; Soldevila, B; Ali, M S; Martínez-Laguna, D; Nogués, X; Puig-Domingo, M; Díez-Pérez, A; Mauricio, D; Prieto-Alhambra, D

2018-06-02

We conducted a nested case-control study to study the association between antidiabetic treatments (alone or in combination) use and fracture risk among incident type 2 Diabetes mellitus patients. We found an increased risk of bone fracture with insulin therapy compared to metformin monotherapy. Patients with type 2 diabetes mellitus (T2DM) have an increased risk of fragility fractures, to which antidiabetic therapies may contribute. We aimed to characterize the risk of fracture associated with different antidiabetic treatments as usually prescribed to T2DM patients in actual practice conditions. A case-control study was nested within a cohort of incident T2DM patients registered in 2006-2012 in the Information System for Research Development in Primary Care (Catalan acronym, SIDIAP), a database which includes records for > 5.5 million patients in Catalonia (Spain). Each case (incident major osteoporotic fracture) was risk-set matched with up to five same-sex controls by calendar year of T2DM diagnosis and year of birth (± 10 years). Study exposure included previous use of all antidiabetic medications (alone or in combination), as dispensed in the 6 months before the index date, with metformin (MTF) monotherapy, the most commonly used drug, as a reference group (active comparator). Data on 12,277 T2DM patients (2049 cases and 10,228 controls) were analyzed. Insulin use was associated with increased fracture risk (adjusted OR 1.63 (95% CI 1.30-2.04)), as was the combination of MTF and sulfonylurea (SU) (adjusted OR 1.29 (1.07-1.56)), compared with MTF monotherapy. Sensitivity analyses suggest possible causality for insulin therapy but not for the MTF + SU combination association. No significant association was found with any other antidiabetic medications. Insulin monotherapy was associated with an increased fracture risk compared to MTF monotherapy in T2DM patients. Fracture risk should be taken into account when starting a glucose-lowering drug as part

Application of Discrete Fracture Modeling and Upscaling Techniques to Complex Fractured Reservoirs

NASA Astrophysics Data System (ADS)

Karimi-Fard, M.; Lapene, A.; Pauget, L.

2012-12-01

During the last decade, an important effort has been made to improve data acquisition (seismic and borehole imaging) and workflow for reservoir characterization which has greatly benefited the description of fractured reservoirs. However, the geological models resulting from the interpretations need to be validated or calibrated against dynamic data. Flow modeling in fractured reservoirs remains a challenge due to the difficulty of representing mass transfers at different heterogeneity scales. The majority of the existing approaches are based on dual continuum representation where the fracture network and the matrix are represented separately and their interactions are modeled using transfer functions. These models are usually based on idealized representation of the fracture distribution which makes the integration of real data difficult. In recent years, due to increases in computer power, discrete fracture modeling techniques (DFM) are becoming popular. In these techniques the fractures are represented explicitly allowing the direct use of data. In this work we consider the DFM technique developed by Karimi-Fard et al. [1] which is based on an unstructured finite-volume discretization. The mass flux between two adjacent control-volumes is evaluated using an optimized two-point flux approximation. The result of the discretization is a list of control-volumes with the associated pore-volumes and positions, and a list of connections with the associated transmissibilities. Fracture intersections are simplified using a connectivity transformation which contributes considerably to the efficiency of the methodology. In addition, the method is designed for general purpose simulators and any connectivity based simulator can be used for flow simulations. The DFM technique is either used standalone or as part of an upscaling technique. The upscaling techniques are required for large reservoirs where the explicit representation of all fractures and faults is not possible

The prevention of hip fracture with menatetrenone and risedronate plus calcium supplementation in elderly patients with Alzheimer disease: a randomized controlled trial.

PubMed

Sato, Yoshihiro; Honda, Yoshiaki; Umeno, Kazuo; Hayashida, Norimasa; Iwamoto, Jun; Takeda, Tsuyoshi; Matsumoto, Hideo

2011-01-01

A high incidence of fractures, particularly of the hip, represents an important problem in patients with Alzheimer disease (AD), who are prone to falls and have osteoporosis. We previously found that vitamin K deficiency and low 25-hydroxyvitamin D (25-OHD) with compensatory hyperparathyroidism cause reduced bone mineral density (BMD) in female patients with AD. This may modifiable by intervention with menatetrenone (vitamin K2) and risedronate sodium; we address the possibility that treatment with menatetrenone, risedronate and calcium may reduce the incidence of nonvertebral fractures in elderly patients with AD. A total of 231 elderly patients with AD were randomly assigned to daily treatment with 45 mg of menatetrenone or a placebo combined with once weekly risedronate sodium, and followed up for 12 months. At baseline, patients of both groups showed high undercarboxylated osteocalcin (ucOC) and low 25-OHD insufficiency with compensatory hyperparathyroidism. During the study period, BMD in the treatment group increased by 5.7% and increased by 2.1% in the control group. Nonvertebral fractures occurred in 15 patients (10 hip fractures) in the control group and 5 patients (2 hip fractures) in the treatment group. The relative risk in the treatment group compared with the control group was 0.31 (95% confidence interval, 0.12-0.81). Elderly AD patients with hypovitaminosis K and D are at increased risk for hip fracture. The study medications were well tolerated with relatively few adverse events and effective in reducing the risk of a fracture in elderly patients with AD.

Simulation and Control Lab Development for Power and Energy Management for NASA Manned Deep Space Missions

NASA Technical Reports Server (NTRS)

McNelis, Anne M.; Beach, Raymond F.; Soeder, James F.; McNelis, Nancy B.; May, Ryan; Dever, Timothy P.; Trase, Larry

2014-01-01

The development of distributed hierarchical and agent-based control systems will allow for reliable autonomous energy management and power distribution for on-orbit missions. Power is one of the most critical systems on board a space vehicle, requiring quick response time when a fault or emergency is identified. As NASAs missions with human presence extend beyond low earth orbit autonomous control of vehicle power systems will be necessary and will need to reliably function for long periods of time. In the design of autonomous electrical power control systems there is a need to dynamically simulate and verify the EPS controller functionality prior to use on-orbit. This paper presents the work at NASA Glenn Research Center in Cleveland, Ohio where the development of a controls laboratory is being completed that will be utilized to demonstrate advanced prototype EPS controllers for space, aeronautical and terrestrial applications. The control laboratory hardware, software and application of an autonomous controller for demonstration with the ISS electrical power system is the subject of this paper.

Exercise and fall prevention self-management to reduce mobility-related disability and falls after fall-related lower limb fracture in older people: protocol for the RESTORE (Recovery Exercises and STepping On afteR fracturE) randomised controlled trial.

PubMed

Sherrington, Catherine; Fairhall, Nicola; Kirkham, Catherine; Clemson, Lindy; Howard, Kirsten; Vogler, Constance; Close, Jacqueline C T; Moseley, Anne M; Cameron, Ian D; Mak, Jenson; Sonnabend, David; Lord, Stephen R

2016-02-02

Lasting disability and further falls are common and costly problems in older people following fall-related lower limb and pelvic fractures. Exercise interventions can improve mobility after fracture and reduce falls in older people, however the optimal approach to rehabilitation after fall-related lower limb and pelvic fracture is unclear. This randomised controlled trial aims to evaluate the effects of an exercise and fall prevention self-management intervention on mobility-related disability and falls in older people following fall-related lower limb or pelvic fracture. Cost-effectiveness of the intervention will also be investigated. A randomised controlled trial with concealed allocation, assessor blinding for physical performance tests and intention-to-treat analysis will be conducted. Three hundred and fifty people aged 60 years and over with a fall-related lower limb or pelvic fracture, who are living at home or in a low care residential aged care facility and have completed active rehabilitation, will be recruited. Participants will be randomised to receive a 12-month intervention or usual care. The intervention group will receive ten home visits from a physiotherapist to prescribe an individualised exercise program with motivational interviewing, plus fall prevention education through individualised advice from the physiotherapist or attendance at the group based "Stepping On" program (seven two-hour group sessions). Participants will be followed for a 12-month period. Primary outcome measures will be mobility-related disability and falls. Secondary outcomes will include measures of balance and mobility, falls risk, physical activity, walking aid use, frailty, pain, nutrition, falls efficacy, mood, positive and negative affect, quality of life, assistance required, hospital readmission, and health-system and community-service contact. This study will determine the effect and cost-effectiveness of this exercise self management intervention on mobility

NASA Curiosity at Site of Clues About Ancient Oxygen

NASA Image and Video Library

2016-06-27

This scene shows NASA's Curiosity Mars rover at a location called "Windjana," where the rover found rocks containing manganese-oxide minerals, which require abundant water and strongly oxidizing conditions to form. In front of the rover are two holes from the rover's sample-collection drill and several dark-toned features that have been cleared of dust (see inset images). These flat features are erosion-resistant fracture fills containing manganese oxides. The discovery of these materials suggests the Martian atmosphere might once have contained higher abundances of free oxygen than it does now. The rover used the Mars Hand Lens Imager (MAHLI) camera in April and May 2014 to take dozens of images that were combined into this self-portrait. http://photojournal.jpl.nasa.gov/catalog/PIA20752

Multi-factor Analysis of Pre-control Fracture Simulations about Projectile Material

NASA Astrophysics Data System (ADS)

Wan, Ren-Yi; Zhou, Wei

2016-05-01

The study of projectile material pre-control fracture is helpful to improve the projectile metal effective fragmentation and the material utilization rate. Fragments muzzle velocity and lethality can be affected by the different explosive charge and the way of initiation. The finite element software can simulate the process of projectile explosive rupture which has a pre-groove in the projectile shell surface and analysis of typical node velocity change with time, to provides a reference for the design and optimization of precontrol frag.

Design and application of nickel-titanium olecranon memory connector in treatment of olecranon fractures: a prospective randomized controlled trial.

PubMed

Chen, Xiao; Liu, Peng; Zhu, Xiaofei; Cao, Liehu; Zhang, Chuncai; Su, Jiacan

2013-06-01

We carried out this study to test the efficacy of the olecranon memory connector (OMC) in olecranon fractures. We designed a prospective randomised controlled trial involving 40 cases of olecranon fractures. From May 2004 to December 2009, 40 patients with olecranon fractures were randomly assigned into two groups. Twenty patients were treated with OMC, while another 20 patients were fixed with locking plates in our hospital. The DASH score, MEP score, range of motion and radiographs were used to evaluate the postoperative elbow function and complications. For MEP score, OMC was better than the locking plate; for DASH score, complication rate, and range of elbow motion, the two methods presented no significant difference. The study showed that OMC could be an effective alternative to treat olecranon fractures.

Modelling Laccoliths: Fluid-Driven Fracturing in the Lab

NASA Astrophysics Data System (ADS)

Ball, T. V.; Neufeld, J. A.

2017-12-01

Current modelling of the formation of laccoliths neglects the necessity to fracture rock layers for propagation to occur [1]. In magmatic intrusions at depth the idea of fracture toughness is used to characterise fracturing, however an analogue for near surface intrusions has yet to be explored [2]. We propose an analytical model for laccolith emplacement that accounts for the energy required to fracture at the tip of an intrusion. For realistic physical parameters we find that a lag region exists between the fluid magma front and the crack tip where large negative pressures in the tip cause volatiles to exsolve from the magma. Crucially, the dynamics of this tip region controls the spreading due to the competition between viscous forces and fracture energy. We conduct a series of complementary experiments to investigate fluid-driven fracturing of adhered layers and confirm the existence of two regimes: viscosity dominant spreading, controlled by the pressure in the lag region, and fracture energy dominant spreading, controlled by the energy required to fracture layers. Our experiments provide the first observations, and evolution, of a vapour tip. These experiments and our simplified model provide insight into the key physical processes in near surface magmatic intrusions with applications to fluid-driven fracturing more generally. Michaut J. Geophys. Res. 116(B5), B05205. Bunger & Cruden J. Geophys. Res. 116(B2), B02203.

NASA Ares I Launch Vehicle Roll and Reaction Control Systems Lessons Learned

NASA Technical Reports Server (NTRS)

Butt, Adam; Popp, Chris G.; Jernigan, Frankie R.; Paseur, Lila F.; Pitts, Hank M.

2011-01-01

On April 15, 2010 President Barak Obama made the official announcement that the Constellation Program, which included the Ares I launch vehicle, would be canceled. NASA s Ares I launch vehicle was being designed to launch the Orion Crew Exploration Vehicle, returning humans to the moon, Mars, and beyond. It consisted of a First Stage (FS) five segment solid rocket booster and a liquid J-2X Upper Stage (US) engine. Roll control for the FS was planned to be handled by a dedicated Roll Control System (RoCS), located on the connecting interstage. Induced yaw or pitch moments experienced during FS ascent would have been handled by vectoring of the booster nozzle. After FS booster separation, the US Reaction Control System (ReCS) would have provided the US Element with three degrees of freedom control as needed. The lessons learned documented in this paper will be focused on the technical designs and producibility of both systems along with the partnership between NASA and Boeing, who was on contract to build the Ares I US Element, which included the FS RoCS and US ReCS. In regards to partnership, focus will be placed on integration along with technical work accomplished by Boeing with special emphasis on each task order. In summary, this paper attempts to capture key lessons learned that should be helpful in the development of future launch vehicle RCS designs.

Fracture Behavior of Boron Aluminum Composites at Room and Elevated Temperatures.

DTIC Science & Technology

1985-04-01

listed in Table I. TABLE I: LIST OF FRACTURE MODELS REVIEWED Authors Ref. Abbrv. Criterion Hole Slits M.E. Waddoups J.R. Eisenmann 3 WEK LEFM V/ SB.E...Laminates: Predictions and Experiemtns - A Review", NASA CR , 1985, (to be published). 3. M.E. Waddoups, J.R. Eisenmann and B.E. Kaminski

L(sub 1) Adaptive Control Design for NASA AirSTAR Flight Test Vehicle

NASA Technical Reports Server (NTRS)

Gregory, Irene M.; Cao, Chengyu; Hovakimyan, Naira; Zou, Xiaotian

2009-01-01

In this paper we present a new L(sub 1) adaptive control architecture that directly compensates for matched as well as unmatched system uncertainty. To evaluate the L(sub 1) adaptive controller, we take advantage of the flexible research environment with rapid prototyping and testing of control laws in the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. We apply the L(sub 1) adaptive control laws to the subscale turbine powered Generic Transport Model. The presented results are from a full nonlinear simulation of the Generic Transport Model and some preliminary pilot evaluations of the L(sub 1) adaptive control law.

Chronic Pancreatitis and Fracture: A Retrospective, Population-Based Veterans Administration Study.

PubMed

Munigala, Satish; Agarwal, Banke; Gelrud, Andres; Conwell, Darwin L

2016-03-01

There is increasing evidence that chronic pancreatitis (CP) is a risk factor for osteoporotic fracture, but data on males with CP and fracture prevalence are sparse. We determined the association of sex and age using a large Veterans Administration database. This was a retrospective analysis (1998-2007). Patients with CP (International Classification of Diseases code 577.1) and control subjects (without CP) were identified after exclusions and fracture prevalence (vertebral, hip, and wrist) were recorded. 453,912 Veterans Administration patients were identified (control subjects: 450,655 and patients with CP: 3257). Mean ages of control subjects and CP were 53.6 and 54.2 years (P < 0.014). Patients with CP had higher odds ratios of total fractures (2.35; 95% confidence interval [CI], 2.00-2.77), vertebral fracture 2.11 (95% CI, 1.44-3.01), hip fracture 3.49 (95% CI, 2.78-4.38), and wrist fracture 1.68 (95% CI, 1.29-2.18) when compared with control subjects. After adjusting for age group and etiology, patients with CP had increased odds of total fractures, vertebral fractures, and hip fractures (P < 0.05). In this male-predominate Veterans Administration study, patients with CP were at increased risk of osteoporotic fractures. The risk was higher for hip fracture (>3 times) in patients with CP compared with control subjects. All patients with CP older than 45 years, irrespective of sex, should be screened for bone mineral density loss.

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.

Fracture process zone in granite

USGS Publications Warehouse

Zang, A.; Wagner, F.C.; Stanchits, S.; Janssen, C.; Dresen, G.

2000-01-01

In uniaxial compression tests performed on Aue granite cores (diameter 50 mm, length 100 mm), a steel loading plate was used to induce the formation of a discrete shear fracture. A zone of distributed microcracks surrounds the tip of the propagating fracture. This process zone is imaged by locating acoustic emission events using 12 piezoceramic sensors attached to the samples. Propagation velocity of the process zone is varied by using the rate of acoustic emissions to control the applied axial force. The resulting velocities range from 2 mm/s in displacement-controlled tests to 2 ??m/s in tests controlled by acoustic emission rate. Wave velocities and amplitudes are monitored during fault formation. P waves transmitted through the approaching process zone show a drop in amplitude of 26 dB, and ultrasonic velocities are reduced by 10%. The width of the process zone is ???9 times the grain diameter inferred from acoustic data but is only 2 times the grain size from optical crack inspection. The process zone of fast propagating fractures is wider than for slow ones. The density of microcracks and acoustic emissions increases approaching the main fracture. Shear displacement scales linearly with fracture length. Fault plane solutions from acoustic events show similar orientation of nodal planes on both sides of the shear fracture. The ratio of the process zone width to the fault length in Aue granite ranges from 0.01 to 0.1 inferred from crack data and acoustic emissions, respectively. The fracture surface energy is estimated from microstructure analysis to be ???2 J. A lower bound estimate for the energy dissipated by acoustic events is 0.1 J. Copyright 2000 by the American Geophysical Union.

Innovative Methodology for Detection of Fracture-Controlled Sweet Spots in the Northern Appalachian Basin

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

Jacobi, Rober

2007-03-31

This Topical Report (#6 of 9) consists of the figures 3.6-13 to (and including) 3.6-18 (and appropriate figure captions) that accompany the Final Technical Progress Report entitled: "Fracture-Controlled Sweet Spots in the Northern Appalachian Basin” for DOE/NETL Award DE-AC26-00NT40698.

Proceedings of the Fifth NASA/NSF/DOD Workshop on Aerospace Computational Control

NASA Technical Reports Server (NTRS)

Wette, M. (Editor); Man, G. K. (Editor)

1993-01-01

The Fifth Annual Workshop on Aerospace Computational Control was one in a series of workshops sponsored by NASA, NSF, and the DOD. The purpose of these workshops is to address computational issues in the analysis, design, and testing of flexible multibody control systems for aerospace applications. The intention in holding these workshops is to bring together users, researchers, and developers of computational tools in aerospace systems (spacecraft, space robotics, aerospace transportation vehicles, etc.) for the purpose of exchanging ideas on the state of the art in computational tools and techniques.

Risk factors for long-bone fractures in children up to 5 years of age: a nested case-control study.

PubMed

Baker, Ruth; Orton, Elizabeth; Tata, Laila J; Kendrick, Denise

2015-05-01

To investigate risk factors for first long-bone fractures in children up to 5 years old in order to provide evidence about which families could benefit from injury prevention interventions. Population-based matched nested case-control study using The Health Improvement Network, a UK primary care research database, 1988-2004. Maternal, household and child risk factors for injury were assessed among 2456 children with long-bone fractures (cases). 23,661 controls were matched to cases on general practice. Adjusted ORs and 95% CIs were estimated using conditional logistic regression. Fractures of long-bones were independently associated with younger maternal age and higher birth order, with children who were the fourth-born in the family, or later, having a threefold greater odds of fracture compared to first-born children (adjusted OR 3.12, 95% CI 2.08 to 4.68). Children over the age of 1 year had a fourfold (13-24 months, adjusted OR 4.09 95% CI 3.51 to 4.76) to fivefold (37+ months, adjusted OR 4.88 95% CI 4.21 to 5.66) increase in the odds of a long-bone fracture compared to children aged 0-12 months. Children in families with a history of maternal alcohol misuse had a raised odds of long-bone fracture (adjusted OR 2.33, 95% CI 1.13 to 4.82) compared to those with no documented history. Risk factors for long-bone fractures in children less than 5 years old included age above 1 year, increasing birth order, younger maternal age and maternal alcohol misuse. These risk factors should be used to prioritise families and communities for injury prevention interventions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Fracture Fluid Additive and Formation Degradations

EPA Pesticide Factsheets

This presentation is on reactions that describe the degradation of fracturing fluids & formations during the hydraulic fracturing process & the clean‐up period. It contains a description of primary chemical reaction controls, & common degradation reactions

Are bi-axial proximal sesamoid bone fractures in the British Thoroughbred racehorse a bone fatigue related fracture? A histological study.

PubMed

Kristoffersen, M; Hetzel, U; Parkin, T D H; Singer, E R

2010-01-01

To investigate whether microfractures and alterations in the trabecular bone area are associated with catastrophic bi-axial proximal sesamoid bone fractures (PSBF). Proximal sesamoid bones (PSB) from 10 racehorses with PSBF and from 10 control racehorses without musculoskeletal injury were examined using the bulk basic fuchsin method. Bone histomorphometric and microfracture analysis was performed, and cases and controls compared using two-sample t-test, paired t-test, and Mann-Whitney U test. There was no significant difference in the microfracture density and the trabecular bone area between bones from case and control horses, and between fractured and non-fractured bones in case horses. Microfracture density was low in the areas of the PSB examined. Microfracture density was not significantly different between groups, indicating that propagation of micro-cracks is an unlikely predisposing pathologic alteration in PSBF in British racehorses. There was no significant difference in the bone surface area between groups, which one would expect if modelling, adaptation and an increase in bone density were associated with PSBF fracture in the case horses. Therefore, PSBF in the British racehorse does not appear to be associated with microfractures of the trabecular bone of the PSB. The PSB fractures might represent an acute monotonic fracture; however, the aetiology of the fractures remains unknown with additional research required.

Effect of Random Natural Fractures on Hydraulic Fracture Propagation Geometry in Fractured Carbonate Rocks

NASA Astrophysics Data System (ADS)

Liu, Zhiyuan; Wang, Shijie; Zhao, Haiyang; Wang, Lei; Li, Wei; Geng, Yudi; Tao, Shan; Zhang, Guangqing; Chen, Mian

2018-02-01

Natural fractures have a significant influence on the propagation geometry of hydraulic fractures in fractured reservoirs. True triaxial volumetric fracturing experiments, in which random natural fractures are created by placing cement blocks of different dimensions in a cuboid mold and filling the mold with additional cement to create the final test specimen, were used to study the factors that influence the hydraulic fracture propagation geometry. These factors include the presence of natural fractures around the wellbore, the dimension and volumetric density of random natural fractures and the horizontal differential stress. The results show that volumetric fractures preferentially formed when natural fractures occurred around the wellbore, the natural fractures are medium to long and have a volumetric density of 6-9%, and the stress difference is less than 11 MPa. The volumetric fracture geometries are mainly major multi-branch fractures with fracture networks or major multi-branch fractures (2-4 fractures). The angles between the major fractures and the maximum horizontal in situ stress are 30°-45°, and fracture networks are located at the intersections of major multi-branch fractures. Short natural fractures rarely led to the formation of fracture networks. Thus, the interaction between hydraulic fractures and short natural fractures has little engineering significance. The conclusions are important for field applications and for gaining a deeper understanding of the formation process of volumetric fractures.

NASA Bioreactor

NASA Technical Reports Server (NTRS)

1996-01-01

Laptop computer sits atop the Experiment Control Computer for a NASA Bioreactor. The flight crew can change operating conditions in the Bioreactor by using the graphical interface on the laptop. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

NASA Bioreactor

NASA Technical Reports Server (NTRS)

1996-01-01

Close-up view of the interior of a NASA Bioreactor shows the plastic plumbing and valves (cylinders at right center) to control fluid flow. The rotating wall vessel is at top center. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

Experimental validation of microseismic emissions from a controlled hydraulic fracture in a synthetic layered medium

NASA Astrophysics Data System (ADS)

Roundtree, Russell

A controlled hydraulic fracture experiment was performed on two medium sized (11" x 11" x 15") synthetic layered blocks of low permeability, low porosity Lyons sandstone sandwiched between cement. The purpose of the research was to better understand and characterize the fracture evolution as the fracture tip impinged upon the layer boundaries between the well bonded layers. It is also one of the first documented uses of passive microseismic used in a laboratory environment to characterize hydraulic fracturing. A relatively low viscosity fluid of 1000 centipoise, compared to properly scaled previous work (Casas 2005, and Athavale 2007), was pumped at a constant rate of 10 mL/minute through a steel cased hole landed and isolated in the sandstone layer. Efforts were made to contain the hydraulic fracture within the confines of the rock specimen to retain the created hydraulic fracture geometry. Two identical samples and treatment schedules were created and differed only in the monitoring system used to characterize the microseismic activity during the fracture treatment. The first block had eight embedded P-wave transducers placed in the sandstone layer to record the passive microseismic emissions and localize the location and time of the acoustic event. The second block had six compressional wave transducers and twelve shear wave transducers embedded in the sandstone layer of the block. The intention was to record and process the seismic data using conventional P-wave to S-wave difference timing techniques well known in industry. While this goal ultimately not possible due to the geometry of the receiver placements and the limitations of the Vallene acquisition processing software, the data received and the events localized from the 18 transducer test were of much higher numbers and quality than on the eight transducer test. This experiment proved conclusively that passive seismic emission recording can yield positive results in the laboratory. Just as in the field

[Petrous bone fracture. Our experience: 1999-2004].

PubMed

Ramírez Sabio, J B; de Paula Vernetta, C; García Sanchís, J M; Callejo García, F J; Cortés Andrés, O; Quilis Quesada, V; Dualde Beltrán, D; Marco Algarra, J

2006-12-01

To review the petrous bone fractures during the last five years (1999-2004) in our hospital, its manage, control, and analysis onf the associated factors. To analyse the managing protocoles and current bibliography. We review 266 temporal bone fractures, 74 with petrous bone association. We analyse these fractures by sex distribution, injurie severity, otorhinolaryngological clinical findings, production mechanism and radiological findings. The cases are discussed and compared with current bibliography. Petrous bone fractures must be always suspected in patients with head trauma, specially if it associates severity and otorrhagia. It is necessary a deep colaboration between neurosurgeons, radiologists and otorhinolaryngologists to obtain a good management, control and follow up of the patients.

Control Activity in Support of NASA Turbine Based Combined Cycle (TBCC) Research

NASA Technical Reports Server (NTRS)

Stueber, Thomas J.; Vrnak, Daniel R.; Le, Dzu K.; Ouzts, Peter J.

2010-01-01

Control research for a Turbine Based Combined Cycle (TBCC) propulsion system is the current focus of the Hypersonic Guidance, Navigation, and Control (GN&C) discipline team. The ongoing work at the NASA Glenn Research Center (GRC) supports the Hypersonic GN&C effort in developing tools to aid the design of control algorithms to manage a TBCC airbreathing propulsion system during a critical operating period. The critical operating period being addressed in this paper is the span when the propulsion system transitions from one cycle to another, referred to as mode transition. One such tool, that is a basic need for control system design activities, is computational models (hereto forth referred to as models) of the propulsion system. The models of interest for designing and testing controllers are Control Development Models (CDMs) and Control Validation Models (CVMs). CDMs and CVMs are needed for each of the following propulsion system elements: inlet, turbine engine, ram/scram dual-mode combustor, and nozzle. This paper presents an overall architecture for a TBCC propulsion system model that includes all of the propulsion system elements. Efforts are under way, focusing on one of the propulsion system elements, to develop CDMs and CVMs for a TBCC propulsion system inlet. The TBCC inlet aerodynamic design being modeled is that of the Combined-Cycle Engine (CCE) Testbed. The CCE Testbed is a large-scale model of an aerodynamic design that was verified in a small-scale screening experiment. The modeling approach includes employing existing state-of-the-art simulation codes, developing new dynamic simulations, and performing system identification experiments on the hardware in the NASA GRC 10 by10-Foot Supersonic Wind Tunnel. The developed CDMs and CVMs will be available for control studies prior to hardware buildup. The system identification experiments on the CCE Testbed will characterize the necessary dynamics to be represented in CDMs for control design. These

Diet-quality scores and risk of hip fractures in elderly urban Chinese in Guangdong, China: a case-control study.

PubMed

Zeng, F F; Xue, W Q; Cao, W T; Wu, B H; Xie, H L; Fan, F; Zhu, H L; Chen, Y M

2014-08-01

This case-control study compared the associations of four widely used diet-quality scoring systems with the risk of hip fractures and assessed their utility in elderly Chinese. We found that individuals avoiding a low-quality diet have a lower risk of hip fractures in elderly Chinese. Few studies examined the associations of diet-quality scores on bone health, and no studies were available in Asians and compared their validity and utility in a study. We assessed the associations and utility of four widely used diet-quality scoring systems with the risk of hip fractures. A case-control study of 726 patients with hip fractures (diagnosed within 2 weeks) aged 55-80 years and 726 age- (within 3 years) and gender-matched controls was conducted in Guangdong, China (2009-2013). Dietary intake was assessed using a 79-item food frequency questionnaire with face-to-face interviews, and the Healthy Eating Index-2005 (HEI-2005, 12 items), the alternate Healthy Eating Index (aHEI, 8 items), the Diet Quality Index-International (DQI-I, 17 items), and the alternate Mediterranean Diet Score (aMed, 9 items) (the simplest one) were calculated. All greater values of the diet-quality scores were significantly associated with a similar decreased risk of hip fractures (all p trends <0.001). The multivariate-adjusted odds ratios (ORs) and 95% confidential intervals (95% CIs) comparing the extreme groups of diet-quality scores were 0.29 (0.18, 0.46) (HEI-2005), 0.20 (0.12, 0.33) (aHEI), 0.25 (0.16, 0.39) (DQI-I), and 0.28 (0.18, 0.43) (aMed) in total subjects; and the corresponding ORs ranged from 0.04 to 0.27 for men and from 0.26 to 0.44 for women (all p trends <0.05), respectively. Avoiding a low-quality diet is associated with a lower risk of hip fractures, and the aMed score is the best scoring system due to its equivalent performance and simplicity for the user.

NASA Integrated Network Monitor and Control Software Architecture

NASA Technical Reports Server (NTRS)

Shames, Peter; Anderson, Michael; Kowal, Steve; Levesque, Michael; Sindiy, Oleg; Donahue, Kenneth; Barnes, Patrick

2012-01-01

The National Aeronautics and Space Administration (NASA) Space Communications and Navigation office (SCaN) has commissioned a series of trade studies to define a new architecture intended to integrate the three existing networks that it operates, the Deep Space Network (DSN), Space Network (SN), and Near Earth Network (NEN), into one integrated network that offers users a set of common, standardized, services and interfaces. The integrated monitor and control architecture utilizes common software and common operator interfaces that can be deployed at all three network elements. This software uses state-of-the-art concepts such as a pool of re-programmable equipment that acts like a configurable software radio, distributed hierarchical control, and centralized management of the whole SCaN integrated network. For this trade space study a model-based approach using SysML was adopted to describe and analyze several possible options for the integrated network monitor and control architecture. This model was used to refine the design and to drive the costing of the four different software options. This trade study modeled the three existing self standing network elements at point of departure, and then described how to integrate them using variations of new and existing monitor and control system components for the different proposed deployments under consideration. This paper will describe the trade space explored, the selected system architecture, the modeling and trade study methods, and some observations on useful approaches to implementing such model based trade space representation and analysis.

Control of the permeability of fractures in geothermal rocks

NASA Astrophysics Data System (ADS)

Faoro, Igor

This thesis comprises three journal articles that will be submitted for publication (Journal of Geophysical Research-Solid Earth). Their respective titles are: "Undrained through Drained Evolution of Permeability in Dual Permeability Media" by Igor Faoro, Derek Elsworth and Chris Marone, "Evolution of Stiffness and Permeability in Fractures Subject to Thermally-and Mechanically-Activated Dissolution" by Igor Faoro, Derek Elsworth Chris Marone; "Linking permeability and mechanical damage for basalt from Mt. Etna volcano (Italy)" by Igor Faoro, Sergio Vinciguerra, Chris Marone and Derek Elsworth. Undrained through Drained Evolution of Permeability in Dual Permeability Media: temporary permeability changes of fractured aquifers subject to earthquakes have been observed and recorded worldwide, but their comprehension still remains a complex issue. In this study we report on flow-through fracture experiments on cracked westerly cores that reproduce, at laboratory scale, those (steps like) permeability changes that have been recorded when earthquakes occur. In particular our experiments show that under specific test boundary conditions, rapid increments of pore pressure induce transient variations of flow rate of the fracture whose peak magnitudes decrease as the variations of the effective stresses increase. We identify that the observed hydraulic behavior of the fracture is due to two principal mechanisms of origin; respectively mechanical (shortening of core) and poro-elastic (radial diffusion of the pore fluid into the matrix of the sample) whose interaction cause respectively an instantaneous opening and then a progressive closure of the fracture. Evolution of Stiffness and Permeability in Fractures Subject to Thermally-and Mechanically-Activated Dissolution: we report the results of radial flow-through experiments conducted on heated samples of Westerly granite. These experiments are performed to examine the influence of thermally and mechanically activated

NASA airframe structural integrity program

NASA Technical Reports Server (NTRS)

Harris, Charles E.

1991-01-01

NASA has initiated a research program with the long-term objective of supporting the aerospace industry in addressing issues related to the aging commercial transport fleet. The interdisciplinary program combines advanced fatigue crack growth prediction methodology with innovative nondestructive examination technology with the focus on multi-site damage (MSD) at riveted connections. A fracture mechanics evaluation of the concept of pressure proof testing the fuselage to screen for MSD has been completed. Also, a successful laboratory demonstration of the ability of the thermal flux method to detect disbonds at riveted lap splice joints has been conducted. All long-term program elements have been initiated and the plans for the methodology verification program are being coordinated with the airframe manufacturers.

NASA airframe structural integrity program

NASA Technical Reports Server (NTRS)

Harris, Charles E.

1990-01-01

NASA initiated a research program with the long-term objective of supporting the aerospace industry in addressing issues related to the aging of the commercial transport fleet. The program combines advanced fatigue crack growth prediction methodology with innovative nondestructive examination technology with the focus on multi-stage damage (MSD) at rivited connections. A fracture mechanics evaluation of the concept of pressure proof testing the fuselage to screen for MSD was completed. A successful laboratory demonstration of the ability of the thermal flux method to detect disbonds at rivited lap splice joints was conducted. All long-term program elements were initiated, and the plans for the methodology verification program are being coordinated with the airframe manufacturers.

Relationship between compliance and persistence with osteoporosis medications and fracture risk in primary health care in France: a retrospective case-control analysis.

PubMed

Cotté, François-Emery; Mercier, Florence; De Pouvourville, Gérard

2008-12-01

Nonadherence to treatment is an important determinant of long-term outcomes in women with osteoporosis. This study was conducted to investigate the association between adherence and osteoporotic fracture risk and to identify optimal thresholds for good compliance and persistence. A secondary objective was to perform a preliminary evaluation of the cost consequences of adherence. This was a retrospective case-control analysis. Data were derived from the Thales prescription database, which contains information on >1.6 million patients in the primary health care setting in France. Cases were women aged >or=50 years who had an osteoporosis-related fracture in 2006. For each case, 5 matched controls were randomly selected. Both compliance and persistence aspects of treatment adherence were examined. Compliance was estimated based on the medication possession ratio (MPR). Persistence was calculated as the time from the initial filling of a prescription for osteoporosis medication until its discontinuation. The mean (SD) MPR was lower in cases compared with controls (58.8% [34.7%] vs 72.1% [28.8%], respectively; P < 0.001). Cases were more likely than controls to discontinue osteoporosis treatment (50.0% vs 25.3%; P < 0.001), yielding a significantly lower proportion of patients who were still persistent at 1 year (34.1% vs 40.9%; P < 0.001). MPR was the best predictor of fracture risk, with an area under the receiver-operating-characteristic curve that was higher than that for persistence (0.59 vs 0.55). The optimal MPR threshold for predicting fracture risk was >or=68.0%. Compared with less-compliant women, women who achieved this threshold had a 51% reduction in fracture risk. The difference in annual drug expenditure between women achieving this threshold and those who did not was approximately euro300. The optimal threshold for persistence with therapy was at least 6 months. Attaining this threshold was associated with a 28% reduction in fracture risk compared with

'NASA Invention of the Year' Controls Noise and Vibration

NASA Technical Reports Server (NTRS)

2007-01-01

Developed at NASA's Langley Research Center, the Macro-Fiber Composite (MFC) is designed to control vibration, noise, and deflections in composite structural beams and panels. Smart Material Corporation specializes in the development of piezocomposite components, and licensed the MFC technology from Langley in 2002. To date, Smart Material Corporation has sold MFCs to over 120 customers, including such industry giants as Volkswagen, Toyota, Honda, BMW, General Electric, and the tennis company, HEAD. The company estimates that its customers have filed at least 100 patents for their various unique uses of the technology. In addition, the company's product portfolio has grown to include piezoceramic fibers and fiber composites, piezoceramic actuators and sensors, and test equipment for these products. It also offers a compact, lightweight power system for MFC testing and validation. Consumer applications already on the market include piezoelectric systems as part of audio speakers, phonograph cartridges and microphones, and recreational products requiring vibration control, such as skis, snowboards, baseball bats, hockey sticks, and tennis racquets.

Paratrooper's Ankle Fracture: Posterior Malleolar Fracture

PubMed Central

Young, Ki Won; Cho, Jae Ho; Kim, Hyung Seuk; Cho, Hun Ki; Lee, Kyung Tai

2015-01-01

Background We assessed the frequency and types of ankle fractures that frequently occur during parachute landings of special operation unit personnel and analyzed the causes. Methods Fifty-six members of the special force brigade of the military who had sustained ankle fractures during parachute landings between January 2005 and April 2010 were retrospectively analyzed. The injury sites and fracture sites were identified and the fracture types were categorized by the Lauge-Hansen and Weber classifications. Follow-up surveys were performed with respect to the American Orthopedic Foot and Ankle Society ankle-hindfoot score, patient satisfaction, and return to preinjury activity. Results The patients were all males with a mean age of 23.6 years. There were 28 right and 28 left ankle fractures. Twenty-two patients had simple fractures and 34 patients had comminuted fractures. The average number of injury and fractures sites per person was 2.07 (116 injuries including a syndesmosis injury and a deltoid injury) and 1.75 (98 fracture sites), respectively. Twenty-three cases (41.07%) were accompanied by posterior malleolar fractures. Fifty-five patients underwent surgery; of these, 30 had plate internal fixations. Weber type A, B, and C fractures were found in 4, 38, and 14 cases, respectively. Based on the Lauge-Hansen classification, supination-external rotation injuries were found in 20 cases, supination-adduction injuries in 22 cases, pronation-external rotation injuries in 11 cases, tibiofibular fractures in 2 cases, and simple medial malleolar fractures in 2 cases. The mean follow-up period was 23.8 months, and the average follow-up American Orthopedic Foot and Ankle Society ankle-hindfoot score was 85.42. Forty-five patients (80.36%) reported excellent or good satisfaction with the outcome. Conclusions Posterior malleolar fractures occurred in 41.07% of ankle fractures sustained in parachute landings. Because most of the ankle fractures in parachute injuries were

Paratrooper's ankle fracture: posterior malleolar fracture.

PubMed

Young, Ki Won; Kim, Jin-su; Cho, Jae Ho; Kim, Hyung Seuk; Cho, Hun Ki; Lee, Kyung Tai

2015-03-01

We assessed the frequency and types of ankle fractures that frequently occur during parachute landings of special operation unit personnel and analyzed the causes. Fifty-six members of the special force brigade of the military who had sustained ankle fractures during parachute landings between January 2005 and April 2010 were retrospectively analyzed. The injury sites and fracture sites were identified and the fracture types were categorized by the Lauge-Hansen and Weber classifications. Follow-up surveys were performed with respect to the American Orthopedic Foot and Ankle Society ankle-hindfoot score, patient satisfaction, and return to preinjury activity. The patients were all males with a mean age of 23.6 years. There were 28 right and 28 left ankle fractures. Twenty-two patients had simple fractures and 34 patients had comminuted fractures. The average number of injury and fractures sites per person was 2.07 (116 injuries including a syndesmosis injury and a deltoid injury) and 1.75 (98 fracture sites), respectively. Twenty-three cases (41.07%) were accompanied by posterior malleolar fractures. Fifty-five patients underwent surgery; of these, 30 had plate internal fixations. Weber type A, B, and C fractures were found in 4, 38, and 14 cases, respectively. Based on the Lauge-Hansen classification, supination-external rotation injuries were found in 20 cases, supination-adduction injuries in 22 cases, pronation-external rotation injuries in 11 cases, tibiofibular fractures in 2 cases, and simple medial malleolar fractures in 2 cases. The mean follow-up period was 23.8 months, and the average follow-up American Orthopedic Foot and Ankle Society ankle-hindfoot score was 85.42. Forty-five patients (80.36%) reported excellent or good satisfaction with the outcome. Posterior malleolar fractures occurred in 41.07% of ankle fractures sustained in parachute landings. Because most of the ankle fractures in parachute injuries were compound fractures, most cases had to

Zoledronic Acid in Reducing Clinical Fracture and Mortality after Hip Fracture

PubMed Central

Lyles, Kenneth W.; Colón-Emeric, Cathleen S.; Magaziner, Jay S.; Adachi, Jonathan D.; Pieper, Carl F.; Mautalen, Carlos; Hyldstrup, Lars; Recknor, Chris; Nordsletten, Lars; Moore, Kathy A.; Lavecchia, Catherine; Zhang, Jie; Mesenbrink, Peter; Hodgson, Patricia K.; Abrams, Ken; Orloff, John J.; Horowitz, Zebulun; Eriksen, Erik Fink; Boonen, Steven

2008-01-01

BACKGROUND Mortality is increased after a hip fracture, and strategies that improve outcomes are needed. METHODS In this randomized, double-blind, placebo-controlled trial, 1065 patients were assigned to receive yearly intravenous zoledronic acid (at a dose of 5 mg), and 1062 patients were assigned to receive placebo. The infusions were first administered within 90 days after surgical repair of a hip fracture. All patients received supplemental vitamin D and calcium. The median follow-up was 1.9 years. The primary end point was a new clinical fracture. RESULTS The rates of any new clinical fracture were 8.6% in the zoledronic acid group and 13.9% in the placebo group, a 35% risk reduction (P = 0.001); the respective rates of a new clinical vertebral fracture were 1.7% and 3.8% (P = 0.02), and the respective rates of new nonvertebral fractures were 7.6% and 10.7% (P = 0.03). In the safety analysis, 101 of 1054 patients in the zoledronic acid group (9.6%) and 141 of 1057 patients in the placebo group (13.3%) died, a reduction of 28% in deaths from any cause in the zoledronic-acid group (P = 0.01). The most frequent adverse events in patients receiving zoledronic acid were pyrexia, myalgia, and bone and musculoskeletal pain. No cases of osteonecrosis of the jaw were reported, and no adverse effects on the healing of fractures were noted. The rates of renal and cardiovascular adverse events, including atrial fibrillation and stroke, were similar in the two groups. CONCLUSIONS An annual infusion of zoledronic acid within 90 days after repair of a low-trauma hip fracture was associated with a reduction in the rate of new clinical fractures and improved survival. (ClinicalTrials.gov number, NCT00046254.) PMID:17878149

Discrete Fracture Network Characterization of Fractured Shale Reservoirs with Implications to Hydraulic Fracturing Optimization

NASA Astrophysics Data System (ADS)

Jin, G.

2016-12-01

Shales are important petroleum source rocks and reservoir seals. Recent developments in hydraulic fracturing technology have facilitated high gas production rates from shale and have had a strong impact on the U.S. gas supply and markets. Modeling of effective permeability for fractured shale reservoirs has been challenging because the presence of a fracture network significantly alters the reservoir hydrologic properties. Due to the frequent occurrence of fracture networks, it is of vital importance to characterize fracture networks and to investigate how these networks can be used to optimize the hydraulic fracturing. We have conducted basic research on 3-D fracture permeability characterization and compartmentization analyses for fractured shale formations, which takes the advantages of the discrete fracture networks (DFN). The DFN modeling is a stochastic modeling approach using the probabilistic density functions of fractures. Three common scenarios of DFN models have been studied for fracture permeability mapping using our previously proposed techniques. In DFN models with moderately to highly concentrated fractures, there exists a representative element volume (REV) for fracture permeability characterization, which indicates that the fractured reservoirs can be treated as anisotropic homogeneous media. Hydraulic fracturing will be most effective if the orientation of the hydraulic fracture is perpendicular to the mean direction of the fractures. A DFN model with randomized fracture orientations, on the other hand, lacks an REV for fracture characterization. Therefore, a fracture permeability tensor has to be computed from each element. Modeling of fracture interconnectivity indicates that there exists no preferred direction for hydraulic fracturing to be most effective oweing to the interconnected pathways of the fracture network. 3-D fracture permeability mapping has been applied to the Devonian Chattanooga Shale in Alabama and the results suggest that an

Innovative Methodology For Detection of Fracture-Controlled Sweet Spots in the Northern Appalachian Basin

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

Jacobi, Rober

2007-03-28

This Topical Report (#6 of 9) consists of the figures 3.6-13 to (and including) 3.6-18 (and appropriate figure captions) that accompany the Final Technical Progress Report entitled: “Innovative Methodology for Detection of Fracture-Controlled Sweet Spots in the Northern Appalachian Basin” for DOE/NETL Award DE-AC26-00NT40698.

NASA's Software Safety Standard

NASA Technical Reports Server (NTRS)

Ramsay, Christopher M.

2007-01-01

NASA relies more and more on software to control, monitor, and verify its safety critical systems, facilities and operations. Since the 1960's there has hardly been a spacecraft launched that does not have a computer on board that will provide command and control services. There have been recent incidents where software has played a role in high-profile mission failures and hazardous incidents. For example, the Mars Orbiter, Mars Polar Lander, the DART (Demonstration of Autonomous Rendezvous Technology), and MER (Mars Exploration Rover) Spirit anomalies were all caused or contributed to by software. The Mission Control Centers for the Shuttle, ISS, and unmanned programs are highly dependant on software for data displays, analysis, and mission planning. Despite this growing dependence on software control and monitoring, there has been little to no consistent application of software safety practices and methodology to NASA's projects with safety critical software. Meanwhile, academia and private industry have been stepping forward with procedures and standards for safety critical systems and software, for example Dr. Nancy Leveson's book Safeware: System Safety and Computers. The NASA Software Safety Standard, originally published in 1997, was widely ignored due to its complexity and poor organization. It also focused on concepts rather than definite procedural requirements organized around a software project lifecycle. Led by NASA Headquarters Office of Safety and Mission Assurance, the NASA Software Safety Standard has recently undergone a significant update. This new standard provides the procedures and guidelines for evaluating a project for safety criticality and then lays out the minimum project lifecycle requirements to assure the software is created, operated, and maintained in the safest possible manner. This update of the standard clearly delineates the minimum set of software safety requirements for a project without detailing the implementation for those

Operative versus non-operative treatment for closed, displaced, intra-articular fractures of the calcaneus: randomised controlled trial.

PubMed

Griffin, Damian; Parsons, Nick; Shaw, Ewart; Kulikov, Yuri; Hutchinson, Charles; Thorogood, Margaret; Lamb, Sarah E

2014-07-24

To investigate whether surgery by open reduction and internal fixation provides benefit compared with non-operative treatment for displaced, intra-articular calcaneal fractures. Pragmatic, multicentre, two arm, parallel group, assessor blinded randomised controlled trial (UK Heel Fracture Trial). 22 tertiary referral hospitals, United Kingdom. 151 patients with acute displaced intra-articular calcaneal fractures randomly allocated to operative (n=73) or non-operative (n=78) treatment. The primary outcome measure was patient reported Kerr-Atkins score for pain and function (scale 0-100, 100 being the best possible score) at two years after injury. Secondary outcomes were complications; hindfoot pain and function (American Orthopaedic Foot and Ankle Society score); general health (SF-36); quality of life (EQ-5D); clinical examination; walking speed; and gait symmetry. Analysis was by intention to treat. 95% follow-up was achieved for the primary outcome (69 in operative group and 74 in non-operative group), and a complete set of secondary outcomes were available for 75% of participants. There was no significant difference in the primary outcome (mean Kerr-Atkins score 69.8 in operative group v 65.7 in non-operative group; adjusted 95% confidence interval of difference -7.1 to 7.0) or in any of the secondary outcomes between treatment groups. Complications and reoperations were more common in those who received operative care (estimated odds ratio 7.5, 95% confidence interval 2.0 to 41.8). Operative treatment compared with non-operative care showed no symptomatic or functional advantage after two years in patients with typical displaced intra-articular fractures of the calcaneus, and the risk of complications was higher after surgery. Based on these findings, operative treatment by open reduction and internal fixation is not recommended for these fractures.Trial registration Current Controlled Trials ISRCTN37188541. © Griffin et al 2014.

Figure-of-eight bandage versus arm sling for treating middle-third clavicle fractures in adults: study protocol for a randomised controlled trial.

PubMed

Lenza, Mario; Taniguchi, Luiz Fabiano Presente; Ferretti, Mario

2016-05-04

Fracture of the clavicle is common, accounting for 2.6 to 4.0 % of all fractures, with an overall incidence of 36.5 to 64 per 100,000 per year. Around 80 % of clavicle fractures occur in the middle third of the clavicle. Randomised controlled trials comparing treatment interventions have failed to indicate the best therapeutic practices for these fractures. The objective of this study is to evaluate the effects (benefits and harms) of two commonly-used conservative interventions: the figure-of-eight bandage versus the arm sling as treatments of middle-third clavicle fractures. This project has been designed as a single-centre, two-arm randomised controlled trial that will compare two interventions: figure-of-eight bandage versus the arm sling. We propose to recruit 110 adults, aged 18 years or older, with an acute (less than 10 days since injury) middle-third clavicle fracture. The primary outcomes to be evaluated will be function and/or disability measured by the Disability of the Arm, Shoulder, and Hand (DASH) questionnaire. In order to assess the secondary outcomes, the Modified University of California at Los Angeles (modified - UCLA) Shoulder Rating Scale will be used. The occurrence of pain (Visual Analogue Scale for pain (VAS)), treatment failure, adverse events and the ability to return to previous activities will also be recorded and evaluated as secondary outcomes. the primary outcome DASH score and the secondary outcomes - modified UCLA and VAS scores - will be analysed graphically. We will apply generalised mixed models with the intervention groups (two levels), and time-point assessments (seven levels) as fixed effects and patients as a random effect. According to the current literature there is very limited evidence from two small trials regarding the effectiveness of different methods of conservative interventions for treating clavicle fractures. This is the first randomised controlled trial comparing the figure-of-eight bandage versus the arm

Role of MRI in hip fractures, including stress fractures, occult fractures, avulsion fractures.

PubMed

Nachtrab, O; Cassar-Pullicino, V N; Lalam, R; Tins, B; Tyrrell, P N M; Singh, J

2012-12-01

MR imaging plays a vital role in the diagnosis and management of hip fractures in all age groups, in a large spectrum of patient groups spanning the elderly and sporting population. It allows a confident exclusion of fracture, differentiation of bony from soft tissue injury and an early confident detection of fractures. There is a spectrum of MR findings which in part is dictated by the type and cause of the fracture which the radiologist needs to be familiar with. Judicious but prompt utilisation of MR in patients with suspected hip fractures has a positive therapeutic impact with healthcare cost benefits as well as social care benefits. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Elastic Rock Heterogeneity Controls Brittle Rock Failure during Hydraulic Fracturing

NASA Astrophysics Data System (ADS)

Langenbruch, C.; Shapiro, S. A.

2014-12-01

For interpretation and inversion of microseismic data it is important to understand, which properties of the reservoir rock control the occurrence probability of brittle rock failure and associated seismicity during hydraulic stimulation. This is especially important, when inverting for key properties like permeability and fracture conductivity. Although it became accepted that seismic events are triggered by fluid flow and the resulting perturbation of the stress field in the reservoir rock, the magnitude of stress perturbations, capable of triggering failure in rocks, can be highly variable. The controlling physical mechanism of this variability is still under discussion. We compare the occurrence of microseismic events at the Cotton Valley gas field to elastic rock heterogeneity, obtained from measurements along the treatment wells. The heterogeneity is characterized by scale invariant fluctuations of elastic properties. We observe that the elastic heterogeneity of the rock formation controls the occurrence of brittle failure. In particular, we find that the density of events is increasing with the Brittleness Index (BI) of the rock, which is defined as a combination of Young's modulus and Poisson's ratio. We evaluate the physical meaning of the BI. By applying geomechanical investigations we characterize the influence of fluctuating elastic properties in rocks on the probability of brittle rock failure. Our analysis is based on the computation of stress fluctuations caused by elastic heterogeneity of rocks. We find that elastic rock heterogeneity causes stress fluctuations of significant magnitude. Moreover, the stress changes necessary to open and reactivate fractures in rocks are strongly related to fluctuations of elastic moduli. Our analysis gives a physical explanation to the observed relation between elastic heterogeneity of the rock formation and the occurrence of brittle failure during hydraulic reservoir stimulations. A crucial factor for understanding

NASA Applications of Molecular Nanotechnology

NASA Technical Reports Server (NTRS)

Globus, Al; Bailey, David; Han, Jie; Jaffe, Richard; Levit, Creon; Merkle, Ralph; Srivastava, Deepak

1998-01-01

Laboratories throughout the world are rapidly gaining atomically precise control over matter. As this control extends to an ever wider variety of materials, processes and devices, opportunities for applications relevant to NASA's missions will be created. This document surveys a number of future molecular nanotechnology capabilities of aerospace interest. Computer applications, launch vehicle improvements, and active materials appear to be of particular interest. We also list a number of applications for each of NASA's enterprises. If advanced molecular nanotechnology can be developed, almost all of NASA's endeavors will be radically improved. In particular, a sufficiently advanced molecular nanotechnology can arguably bring large scale space colonization within our grasp.

Femoral nerve block in a representative sample of elderly people with hip fracture: A randomised controlled trial.

PubMed

Unneby, Anna; Svensson, Olle; Gustafson, Yngve; Olofsson, Birgitta

2017-07-01

The number of elderly people with hip fracture and dementia is increasing, and many of these patients suffer from pain. Opioids are difficult to adjust and side effects are common, especially with increased age and among patients with dementia. Preoperative femoral nerve block is an alternative pain treatment. To investigate whether preoperative femoral nerve block reduced acute pain and opioid use after hip fracture among elderly patients, including those with dementia. In this randomised controlled trial involving patients aged ≥70years with hip fracture (trochanteric and cervical), including those with dementia, we compared femoral nerve block with conventional pain management, with opioid use if required. The primary outcome was preoperative pain, measured at five timepoints using a visual analogue scale (VAS). Preoperative opioid consumption was also registered. The study sample comprised 266 patients admitted consecutively to the Orthopaedic Ward. The mean age was 84.1 (±6.9)years, 64% of participants were women, 44% lived in residential care facilities, and 120 (45.1%) had dementia diagnoses. Patients receiving femoral nerve block had significantly lower self-rated pain scores from baseline to 12h after admission than did controls. Self-rated and proxy VAS pain scores decreased significantly in these patients from baseline to 12h compared with controls (p<0.001 and p=0.003, respectively). Patients receiving femoral nerve block required less opioids than did controls, overall (2.3±4.0 vs. 5.7±5.2mg, p<0.001) and in the subgroup with dementia (2.1±3.3 vs. 5.8±5.0mg, p<0.001). Patients with hip fracture, including those with dementia, who received femoral nerve block had lower pain scores and required less opioids before surgery compared with those receiving conventional pain management. Femoral nerve block seems to be a feasible pain treatment for elderly people, including those with dementia. Copyright © 2017 The Authors. Published by Elsevier Ltd

Fracture Characterization in Reactive Fluid-Fractured Rock Systems Using Tracer Transport Data

NASA Astrophysics Data System (ADS)

Mukhopadhyay, S.

2014-12-01

Fractures, whether natural or engineered, exert significant controls over resource exploitation from contemporary energy sources including enhanced geothermal systems and unconventional oil and gas reserves. Consequently, fracture characterization, i.e., estimating the permeability, connectivity, and spacing of the fractures is of critical importance for determining the viability of any energy recovery program. While some progress has recently been made towards estimating these critical fracture parameters, significant uncertainties still remain. A review of tracer technology, which has a long history in fracture characterization, reveals that uncertainties exist in the estimated parameters not only because of paucity of scale-specific data but also because of knowledge gaps in the interpretation methods, particularly in interpretation of tracer data in reactive fluid-rock systems. We have recently demonstrated that the transient tracer evolution signatures in reactive fluid-rock systems are significantly different from those in non-reactive systems (Mukhopadhyay et al., 2013, 2014). For example, the tracer breakthrough curves in reactive fluid-fractured rock systems are expected to exhibit a long pseudo-state condition, during which tracer concentration does not change by any appreciable amount with passage of time. Such a pseudo-steady state condition is not observed in a non-reactive system. In this paper, we show that the presence of this pseudo-steady state condition in tracer breakthrough patterns in reactive fluid-rock systems can have important connotations for fracture characterization. We show that the time of onset of the pseudo-steady state condition and the value of tracer concentration in the pseudo-state condition can be used to reliably estimate fracture spacing and fracture-matrix interface areas.

NASA Ames 2016 Highlights

NASA Image and Video Library

2016-12-28

2016 presented the opportunity for NASA's Ames Research Center to meet its challenges and opportunities head on. Projects ranged from testing the next generation of air traffic control software to studying the stars of our galaxy. From developing life science experiments that flew aboard the International Space Station to helping protect our planet through airborne Earth observation campaigns. NASA's missions and programs are challenging and the people at NASA Ames Research Center continue to reach new heights and reveal the unknown for the benefit of all humankind!

NASA Bioreactor

NASA Technical Reports Server (NTRS)

1996-01-01

Exterior view of the NASA Bioreactor Engineering Development Unit flown on Mir. The rotating wall vessel is behind the window on the face of the large module. Control electronics are in the module at left; gas supply and cooling fans are in the module at back. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

The Electronic Documentation Project in the NASA mission control center environment

NASA Technical Reports Server (NTRS)

Wang, Lui; Leigh, Albert

1994-01-01

NASA's space programs like many other technical programs of its magnitude is supported by a large volume of technical documents. These documents are not only diverse but also abundant. Management, maintenance, and retrieval of these documents is a challenging problem by itself; but, relating and cross-referencing this wealth of information when it is all on a medium of paper is an even greater challenge. The Electronic Documentation Project (EDP) is to provide an electronic system capable of developing, distributing and controlling changes for crew/ground controller procedures and related documents. There are two primary motives for the solution. The first motive is to reduce the cost of maintaining the current paper based method of operations by replacing paper documents with electronic information storage and retrieval. And, the other is to improve the efficiency and provide enhanced flexibility in document usage. Initially, the current paper based system will be faithfully reproduced in an electronic format to be used in the document viewing system. In addition, this metaphor will have hypertext extensions. Hypertext features support basic functions such as full text searches, key word searches, data retrieval, and traversal between nodes of information as well as speeding up the data access rate. They enable related but separate documents to have relationships, and allow the user to explore information naturally through non-linear link traversals. The basic operational requirements of the document viewing system are to: provide an electronic corollary to the current method of paper based document usage; supplement and ultimately replace paper-based documents; maintain focused toward control center operations such as Flight Data File, Flight Rules and Console Handbook viewing; and be available NASA wide.

Levothyroxine treatment and occurrence of fracture of the hip.

PubMed

Sheppard, Michael C; Holder, Roger; Franklyn, Jayne A

2002-02-11

Levothyroxine sodium is widely prescribed and has been implicated as a cause of reduction in bone mineral density and, therefore, suggested to be a major contributor to the risk of osteoporotic fractures. To investigate whether levothyroxine use increases the risk of developing osteoporotic fractures. We conducted a population-based, case-control analysis of the risk of a femur fracture in a large cohort of patients who had been prescribed levothyroxine. We used the United Kingdom General Practice (primary care) Research Database to identify 23,183 patients who had been prescribed long-term thyroid hormone therapy and to identify for each patient taking levothyroxine 4 controls matched for age, sex, primary care practice, and duration of registration on the database. The number of patients who had sustained a fracture of the proximal femur was ascertained for each group, together with drug therapies and medical diagnoses likely to affect fracture risk. Of the 23,183 patients prescribed thyroid hormone, a mean +/- SE of 1.61% +/- 0.08% had sustained a fracture of the femur, compared with 1.44% +/- 0.04% of 92,732 controls (P =.06). When analyzed according to sex, a significant difference in rate of fracture between patients taking levothyroxine and controls was found in males (P =.008). Compared with controls, patients taking levothyroxine had higher reported rates of medical diagnoses and therapies, potentially confounding the fracture risk. Independent predictors of the occurrence of fracture after adjustment for other factors were age (adjusted odds ratio [AOR], 1.11; 95% confidence interval [CI], 1.10-1.11; P<.001), medical diagnoses including rheumatoid arthritis (AOR in females, 1.69; 95% CI, 1.27-2.26; P<.001), excessive use of alcohol (AOR in females, 3.05; 95% CI, 1.94-4.76; P<.001), and prescription of drugs (eg, anticonvulsants; AOR in females, 2.49; 95% CI, 2.00-3.09; P<.001). Prescription of levothyroxine was an independent predictor of fracture

Application of NASA-developed technology to the automatic control of municipal sewage treatment plants

NASA Technical Reports Server (NTRS)

Hiser, L. L.; Herrera, W. R.

1973-01-01

A search was made of NASA developed technology and commercial technology for process control sensors and instrumentation which would be applicable to the operation of municipal sewage treatment plants. Several notable items were found from which process control concepts were formulated that incorporated these items into systems to automatically operate municipal sewage treatment plants. A preliminary design of the most promising concept was developed into a process control scheme for an activated sludge treatment plant. This design included process control mechanisms for maintaining constant food to sludge mass (F/M) ratio, and for such unit processes as primary sedimentation, sludge wastage, and underflow control from the final clarifier.

Nurse case-manager vs multifaceted intervention to improve quality of osteoporosis care after wrist fracture: randomized controlled pilot study.

PubMed

Majumdar, S R; Johnson, J A; Bellerose, D; McAlister, F A; Russell, A S; Hanley, D A; Garg, S; Lier, D A; Maksymowych, W P; Morrish, D W; Rowe, B H

2011-01-01

Few outpatients with fractures are treated for osteoporosis in the years following fracture. In a randomized pilot study, we found a nurse case-manager could double rates of osteoporosis testing and treatment compared with a proven efficacious quality improvement strategy directed at patients and physicians (57% vs 28% rates of appropriate care). Few patients with fractures are treated for osteoporosis. An intervention directed at wrist fracture patients (education) and physicians (guidelines, reminders) tripled osteoporosis treatment rates compared to controls (22% vs 7% within 6 months of fracture). More effective strategies are needed. We undertook a pilot study that compared a nurse case-manager to the multifaceted intervention using a randomized trial design. The case-manager counseled patients, arranged bone mineral density (BMD) tests, and prescribed treatments. We included controls from our first trial who remained untreated for osteoporosis 1-year post-fracture. Primary outcome was bisphosphonate treatment and secondary outcomes were BMD testing, appropriate care (BMD test-treatment if bone mass low), and costs. Forty six patients untreated 1-year after wrist fracture were randomized to case-manager (n = 21) or multifaceted intervention (n = 25). Median age was 60 years and 68% were female. Six months post-randomization, 9 (43%) case-managed patients were treated with bisphosphonates compared with 3 (12%) multifaceted intervention patients (relative risk [RR] 3.6, 95% confidence intervals [CI] 1.1-11.5, p = 0.019). Case-managed patients were more likely than multifaceted intervention patients to undergo BMD tests (81% vs 52%, RR 1.6, 95%CI 1.1-2.4, p = 0.042) and receive appropriate care (57% vs 28%, RR 2.0, 95%CI 1.0-4.2, p = 0.048). Case-management cost was $44 (CDN) per patient vs $12 for the multifaceted intervention. A nurse case-manager substantially increased rates of appropriate testing and treatment for osteoporosis in

The NASA Mission Operations and Control Architecture Program

NASA Technical Reports Server (NTRS)

Ondrus, Paul J.; Carper, Richard D.; Jeffries, Alan J.

1994-01-01

The conflict between increases in space mission complexity and rapidly declining space mission budgets has created strong pressures to radically reduce the costs of designing and operating spacecraft. A key approach to achieving such reductions is through reducing the development and operations costs of the supporting mission operations systems. One of the efforts which the Communications and Data Systems Division at NASA Headquarters is using to meet this challenge is the Mission Operations Control Architecture (MOCA) project. Technical direction of this effort has been delegated to the Mission Operations Division (MOD) of the Goddard Space Flight Center (GSFC). MOCA is to develop a mission control and data acquisition architecture, and supporting standards, to guide the development of future spacecraft and mission control facilities at GSFC. The architecture will reduce the need for around-the-clock operations staffing, obtain a high level of reuse of flight and ground software elements from mission to mission, and increase overall system flexibility by enabling the migration of appropriate functions from the ground to the spacecraft. The end results are to be an established way of designing the spacecraft-ground system interface for GSFC's in-house developed spacecraft, and a specification of the end to end spacecraft control process, including data structures, interfaces, and protocols, suitable for inclusion in solicitation documents for future flight spacecraft. A flight software kernel may be developed and maintained in a condition that it can be offered as Government Furnished Equipment in solicitations. This paper describes the MOCA project, its current status, and the results to date.

Does self-efficacy mediate functional change in older adults participating in an exercise program after hip fracture? A randomized controlled trial.

PubMed

Chang, Feng-Hang; Latham, Nancy K; Ni, Pengsheng; Jette, Alan M

2015-06-01

To examine whether self-efficacy mediated the effect of the Home-based Post-Hip Fracture Rehabilitation program on activity limitations in older adults after hip fracture and whether the mediating effect was different between sex and age groups. Randomized controlled trial. Community. Participants with hip fracture (N=232; mean age ± SD, 79±9.4y) were randomly assigned to intervention (n=120, 51.7%) and attention control (n=112, 48.3%) groups. The 6-month intervention, the Home-based Post-Hip Fracture Rehabilitation, is a functionally oriented, home-based exercise program. Data were collected at baseline, postintervention (6mo), and follow-up (9mo). Activity Measure for Post-Acute Care. The mediating effect of the Home-based Post-Hip Fracture Rehabilitation program on Basic Mobility function through self-efficacy for exercise was significant at 9 months (βindirect=.21). Similarly, the mediating effect of the intervention on Daily Activity function through self-efficacy for exercise was significant at 9 months (βindirect=.49). In subgroup analyses, the mediating effect was significant at 9 months in the younger group (age, ≤79y) in comparison to the older group and was significant in women in comparison to men. Self-efficacy may play a partial mediating role in the effect on some longer-term functional outcomes in the Home-based Post-Hip Fracture Rehabilitation intervention. The results suggest that program components that target self-efficacy should be incorporated in future hip fracture rehabilitation interventions. Age and sex of the targeted participants may also need to be considered when developing interventions. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Uncertainty Analysis of Simulated Hydraulic Fracturing

NASA Astrophysics Data System (ADS)

Chen, M.; Sun, Y.; Fu, P.; Carrigan, C. R.; Lu, Z.

2012-12-01

Artificial hydraulic fracturing is being used widely to stimulate production of oil, natural gas, and geothermal reservoirs with low natural permeability. Optimization of field design and operation is limited by the incomplete characterization of the reservoir, as well as the complexity of hydrological and geomechanical processes that control the fracturing. Thus, there are a variety of uncertainties associated with the pre-existing fracture distribution, rock mechanics, and hydraulic-fracture engineering that require evaluation of their impact on the optimized design. In this study, a multiple-stage scheme was employed to evaluate the uncertainty. We first define the ranges and distributions of 11 input parameters that characterize the natural fracture topology, in situ stress, geomechanical behavior of the rock matrix and joint interfaces, and pumping operation, to cover a wide spectrum of potential conditions expected for a natural reservoir. These parameters were then sampled 1,000 times in an 11-dimensional parameter space constrained by the specified ranges using the Latin-hypercube method. These 1,000 parameter sets were fed into the fracture simulators, and the outputs were used to construct three designed objective functions, i.e. fracture density, opened fracture length and area density. Using PSUADE, three response surfaces (11-dimensional) of the objective functions were developed and global sensitivity was analyzed to identify the most sensitive parameters for the objective functions representing fracture connectivity, which are critical for sweep efficiency of the recovery process. The second-stage high resolution response surfaces were constructed with dimension reduced to the number of the most sensitive parameters. An additional response surface with respect to the objective function of the fractal dimension for fracture distributions was constructed in this stage. Based on these response surfaces, comprehensive uncertainty analyses were conducted

Rib fractures in trauma patients: does operative fixation improve outcome?

PubMed

Majak, Peter; Næss, Pål A

2016-12-01

Renewed interest in surgical fixation of rib fractures has emerged. However, conservative treatment is still preferred at most surgical departments. We wanted to evaluate whether operative treatment of rib fractures may benefit severely injured patients. Several studies report a reduction in mechanical ventilation time, ICU length of stay (LOS), hospital LOS, pneumonia, need for tracheostomy, pain and costs in operatively treated patients with multiple rib fractures compared with patients treated nonoperatively. Although patient selection and timing of the operation seem crucial for successful outcome, no consensus exists. Mortality reduction has only been shown in a few studies. Most studies are retrospective cohort and case-control studies. Only four randomized control trials exist. Conservative treatment, consisting of respiratory assistance and pain control, is still the treatment of choice in the vast majority of patients with multiple rib fractures. In selected patients, operative fixation of fractured ribs within 72 h postinjury may lead to better outcome. More randomized control trials are needed to further determine who benefits from surgical fixation of rib fractures.

VEGF serum concentrations in patients with long bone fractures: a comparison between impaired and normal fracture healing.

PubMed

Sarahrudi, Kambiz; Thomas, Anita; Braunsteiner, Tomas; Wolf, Harald; Vécsei, Vilmos; Aharinejad, Seyedhossein

2009-10-01

Vascular endothelial growth factor (VEGF) plays an important role in the bone repair process as a potent mediator of angiogenesis and it influences directly osteoblast differentiation. Inhibiting VEGF suppresses angiogenesis and callus mineralization in animals. However, no data exist so far on systemic expression of VEGF with regard to delayed or failed fracture healing in humans. One hundred fourteen patients with long bone fractures were included in the study. Serum samples were collected over a period of 6 months following a standardized time schedule. VEGF serum concentrations were measured. Patients were assigned to one of two groups according to their course of fracture healing. The first group contained 103 patients with physiological fracture healing. Eleven patients with delayed or nonunions formed the second group of the study. In addition, 33 healthy volunteers served as controls. An increase of VEGF serum concentration within the first 2 weeks after fracture in both groups with a following decrease within 6 months after trauma was observed. Serum VEGF concentrations in patients with impaired fracture healing were higher compared to the patients with physiological healing during the entire observation period. However, statistically significant differences were not observed at any time point between both groups. VEGF concentrations in both groups were significantly higher than those in controls. The present results show significantly elevated serum concentrations of VEGF in patients after fracture of long bones especially at the initial healing phase, indicating the importance of VEGF in the process of fracture healing in humans. (c) 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Self-Reported Fractures in Dermatitis Herpetiformis Compared to Coeliac Disease

PubMed Central

Pasternack, Camilla; Mansikka, Eriika; Kaukinen, Katri; Hervonen, Kaisa; Reunala, Timo; Collin, Pekka; Mattila, Ville M.

2018-01-01

Dermatitis herpetiformis (DH) is a cutaneous manifestation of coeliac disease. Increased bone fracture risk is known to associate with coeliac disease, but this has been only scantly studied in DH. In this study, self-reported fractures and fracture-associated factors in DH were investigated and compared to coeliac disease. Altogether, 222 DH patients and 129 coeliac disease-suffering controls were enrolled in this study. The Disease Related Questionnaire and the Gastrointestinal Symptom Rating Scale and Psychological General Well-Being questionnaires were mailed to participants; 45 out of 222 (20%) DH patients and 35 out of 129 (27%) of the coeliac disease controls had experienced at least one fracture (p = 0.140). The cumulative lifetime fracture incidence did not differ between DH and coeliac disease patients, but the cumulative incidence of fractures after diagnosis was statistically significantly higher in females with coeliac disease compared to females with DH. The DH patients and the coeliac disease controls with fractures reported more severe reflux symptoms compared to those without, and they also more frequently used proton-pump inhibitor medication. To conclude, the self-reported lifetime bone fracture risk is equal for DH and coeliac disease. After diagnosis, females with coeliac disease have a higher fracture risk than females with DH. PMID:29538319

Hypnotics and the Occurrence of Bone Fractures in Hospitalized Dementia Patients: A Matched Case-Control Study Using a National Inpatient Database.

PubMed

Tamiya, Hiroyuki; Yasunaga, Hideo; Matusi, Hiroki; Fushimi, Kiyohide; Ogawa, Sumito; Akishita, Masahiro

2015-01-01

Preventing falls and bone fractures in hospital care is an important issue in geriatric medicine. Use of hypnotics is a potential risk factor for falls and bone fractures in older patients. However, data are lacking on the association between use of hypnotics and the occurrence of bone fracture. We used a national inpatient database including 1,057 hospitals in Japan and included dementia patients aged 50 years or older who were hospitalized during a period of 12 months between April 2012 and March 2013. The primary outcome was the occurrence of bone fracture during hospitalization. Use of hypnotics was compared between patients with and without bone fracture in this matched case-control study. Of 140,494 patients, 830 patients suffered from in-hospital fracture. A 1:4 matching with age, sex and hospital created 817 cases with fracture and 3,158 matched patients without fracture. With adjustment for the Charlson comorbidity index, emergent admission, activities of daily living, and scores for level walking, a higher occurrence of fractures were seen with short-acting benzodiazepine hypnotics (odds ratio, 1.43; 95% confidence interval, 1.19-1.73; P<0.001), ultrashort-acting non-benzodiazepine hypnotics (1.66; 1.37-2.01; P<0.001), hydroxyzine (1.45; 1.15-1.82, P=0.001), risperidone and perospirone (1.37; 1.08-1.73; P=0.010). Other drug groups were not significantly associated with the occurrence of in-hospital fracture. Short-acting benzodiazepine hypnotics and ultrashort-acting non-benzodiazepine hypnotics may increase risk of bone fracture in hospitalized dementia patients.

Effects of 18-month low-magnitude high-frequency vibration on fall rate and fracture risks in 710 community elderly--a cluster-randomized controlled trial.

PubMed

Leung, K S; Li, C Y; Tse, Y K; Choy, T K; Leung, P C; Hung, V W Y; Chan, S Y; Leung, A H C; Cheung, W H

2014-06-01

This study is a prospective cluster-randomized controlled clinical trial involving 710 elderly subjects to investigate the long-term effects of low-magnitude high-frequency vibration (LMHFV) on fall and fracture rates, muscle performance, and bone quality. The results confirmed that LMHFV is effective in reducing fall incidence and enhancing muscle performance in the elderly. Falls are direct causes of fragility fracture in the elderly. LMHFV has been shown to improve muscle function and bone quality. This study is to investigate the efficacy of LMHFV in preventing fall and fractures among the elderly in the community. A cluster-randomized controlled trial was conducted with 710 postmenopausal females over 60 years. A total of 364 participants received daily 20 min LMHFV (35 Hz, 0.3 g), 5 days/week for 18 months; 346 participants served as control. Fall or fracture rate was taken as the primary outcome. Also, quadriceps muscle strength, balancing abilities, bone mineral density (BMD), and quality of life (QoL) assessments were done at 0, 9, and 18 months. With an average of 66.0% compliance in the vibration group, 18.6% of 334 vibration group subjects reported fall or fracture incidences compared with 28.7% of 327 in the control (adjusted HR = 0.56, p = 0.001). The fracture rate of vibration and control groups were 1.1 and 2.3 % respectively (p = 0.171). Significant improvements were found in reaction time, movement velocity, and maximum excursion of balancing ability assessment, and also the quadriceps muscle strength (p < 0.001). No significant differences were found in the overall change of BMD. Minimal adverse effects were documented. LMHFV is effective in fall prevention with improved muscle strength and balancing ability in the elderly. We recommend its use in the community as an effective fall prevention program and to decrease related injuries.

Fracture probability assessed using FRAX® in elderly women with benign paroxysmal positional vertigo.

PubMed

Nakada, Takafumi; Teranishi, Masaaki; Ueda, Yukio; Sone, Michihiko

2018-05-18

Patients with benign paroxysmal positional vertigo (BPPV) can have vitamin D deficiency, which is a cause of abnormal bone turnover. Several studies have established a relationship between osteoporosis and BPPV. The World Health Organization Fracture Risk Assessment Tool, widely known as FRAX ® (http://www.shef.ac.uk/FRAX), is a computer-based algorithm for assessing fracture risk. No direct comparison has been made between the FRAX scores of patients with BPPV and controls. The purpose of this study was to determine whether women with BPPV are at high risk of fracture as assessed using FRAX. The study involved 40 postmenopausal women diagnosed with BPPV between July 2015 and April 2016, and 40 postmenopausal women as controls. The 10-year major osteoporotic and hip fracture risks were calculated using FRAX and were compared between BPPV patients and controls using Welch's t test and a general linear model. The 10-year major osteoporotic fracture risk was 20.4%±12.1% for BPPV patients (aged 72.4±8.6years) and 14.3%±6.5% for controls (aged 71.2±6.3years). The 10-year hip fracture risk was 9.0%±9.8% for BPPV patients and 5.0%±3.9% for controls. The BPPV group had significantly higher 10-year major risks of osteoporotic fracture (p=0.0069) and hip fracture (p=0.0202) compared with controls. Similarly, after adjustment for age, the BPPV group had significantly higher 10-year risks of major osteoporotic fracture (p=0.0007) and hip fracture (p=0.0092) compared with controls. Fracture risk calculated using FRAX was significantly higher in the BPPV group than in controls. Women with BPPV may need early intervention to prevent future fractures. Copyright © 2018 Elsevier B.V. All rights reserved.

Design, fracture control, fabrication, and testing of pressurized space-vehicle structures

NASA Technical Reports Server (NTRS)

Babel, H. W.; Christensen, R. H.; Dixon, H. H.

1974-01-01

The relationship between analysis, design, fabrication, and testing of thin shells is illustrated by Saturn S-IVB, Thor, Delta, and other single-use and reusable large-size cryogenic aluminum tankage. The analyses and design to meet the design requirements are reviewed and include consideration of fracture control, general instability, and other failure modes. The effect of research and development testing on the structure is indicated. It is shown how fabrication and nondestructive and acceptance testing constrain the design. Finally, qualification testing is reviewed to illustrate the extent of testing used to develop the Saturn S-IVB.

Growth Kinematics of Opening-Mode Fractures

NASA Astrophysics Data System (ADS)

Eichhubl, P.; Alzayer, Y.; Laubach, S.; Fall, A.

2014-12-01

Fracture aperture is a primary control on flow in fractured reservoirs of low matrix permeability including unconventional oil and gas reservoirs and most geothermal systems. Guided by principles of linear elastic fracture mechanics, fracture aperture is generally assumed to be a linear function of fracture length and elastic material properties. Natural opening-mode fractures with significant preserved aperture are observed in core and outcrop indicative of fracture opening strain accommodated by permanent solution-precipitation creep. Fracture opening may thus be decoupled from length growth if the material effectively weakens after initial elastic fracture growth by either non-elastic deformation processes or changes in elastic properties. To investigate the kinematics of fracture length and aperture growth, we reconstructed the opening history of three opening-mode fractures that are bridged by crack-seal quartz cement in Travis Peak Sandstone of the SFOT-1 well, East Texas. Similar crack-seal cement bridges had been interpreted to form by repeated incremental fracture opening and subsequent precipitation of quartz cement. We imaged crack-seal cement textures for bridges sampled at varying distance from the tips using scanning electron microscope cathodoluminescence, and determined the number and thickness of crack-seal cement increments as a function of position along the fracture length and height. Observed trends in increment number and thickness are consistent with an initial stage of fast fracture propagation relative to aperture growth, followed by a stage of slow propagation and pronounced aperture growth. Consistent with fluid inclusion observations indicative of fracture opening and propagation occurring over 30-40 m.y., we interpret the second phase of pronounced aperture growth to result from fracture opening strain accommodated by solution-precipitation creep and concurrent slow, possibly subcritical, fracture propagation. Similar deformation

A new state space model for the NASA/JPL 70-meter antenna servo controls

NASA Technical Reports Server (NTRS)

Hill, R. E.

1987-01-01

A control axis referenced model of the NASA/JPL 70-m antenna structure is combined with the dynamic equations of servo components to produce a comprehansive state variable (matrix) model of the coupled system. An interactive Fortran program for generating the linear system model and computing its salient parameters is described. Results are produced in a state variable, block diagram, and in factored transfer function forms to facilitate design and analysis by classical as well as modern control methods.

Operative Fixation of Rib Fractures Indications, Techniques, and Outcomes.

PubMed

Galos, David; Taylor, Benjamin; McLaurin, Toni

2017-01-01

Rib fractures are extremely common injuries and vary in there severity from single nondisplaced fractures to multiple segmental fractures resulting in flail chest and respiratory compromise. Historically, rib fractures have been treated conservatively with pain control and respiratory therapy. However this method may not be the best treatment modality in all situations. Operative fixation of select rib fractures has been increasing in popularity especially in patients with flail chest and respiratory compromise. Newer techniques use muscle sparing approaches and precontoured locking plate technology to obtain stable fixation and allow improved respiration. Current reports shows that rib fracture fixation offers the benefits of improved respiratory mechanics and improved pain control in the severe chest wall injury with resultant improvement in patient outcomes by decreasing time on the ventilator, time in the intensive care unit, and overall hospital length of stay.

The Role of Electrical Anisotropy in Modeling and Interpreting Controlled-Source Electromagnetic Responses for Hydraulic Fracture Monitoring

NASA Astrophysics Data System (ADS)

Trevino, S., III; Hickey, M. S.; Everett, M. E.

2017-12-01

Controlled-Source Electromagnetics (CSEM) can be used to monitor the movement and extent of injection fluid during a hydraulic fracture. The response of the fluid to energization by a CSEM source is dependent upon the electrical conductivity difference between the fluid and background geological formation. An important property that must be taken into account when modeling and interpreting CSEM responses is that electrical conductivity may be anisotropic. We study the effect of electrical anisotropy in both the background formation and the fluid-injection zone. First, various properties of the background formation can affect anisotropy including variations in grain size, composition and bedding-plane orientation. In certain formations, such as shale, the horizontal component of the conductivity can be more than an order of magnitude larger than the vertical component. We study this effect by computing differences in surface CSEM responses using the analytic 1-D anisotropic primary solution of a horizontal electric dipole positioned at the surface. Second, during hydraulic fracturing, the injected fluid can create new fractures and infill existing natural fractures. To include the explicit fracture geometry in modeling, a large increase in the number of nodes and computational time is required which may not be feasible. An alternative is to instead model the large-scale fracture geometry as a uniform slab with an appropriate bulk conductivity. Micro-scale fracture geometry may cause preferential fluid propagation in a single direction or plane which can be represented by electrical anisotropy of the slab. To study such effects of bulk anisotropy on CSEM responses we present results from multiple scenarios of surface to surface hydraulic fracture monitoring using 3-D finite element modeling. The model uses Coulomb-gauged potentials to solve Maxwell's equations in the frequency domain and we have updated the code to allow a triaxial electrical conductivity tensor to

Fracture size and transmissivity correlations: Implications for transport simulations in sparse three-dimensional discrete fracture networks following a truncated power law distribution of fracture size

NASA Astrophysics Data System (ADS)

Hyman, J. D.; Aldrich, G.; Viswanathan, H.; Makedonska, N.; Karra, S.

2016-08-01

We characterize how different fracture size-transmissivity relationships influence flow and transport simulations through sparse three-dimensional discrete fracture networks. Although it is generally accepted that there is a positive correlation between a fracture's size and its transmissivity/aperture, the functional form of that relationship remains a matter of debate. Relationships that assume perfect correlation, semicorrelation, and noncorrelation between the two have been proposed. To study the impact that adopting one of these relationships has on transport properties, we generate multiple sparse fracture networks composed of circular fractures whose radii follow a truncated power law distribution. The distribution of transmissivities are selected so that the mean transmissivity of the fracture networks are the same and the distributions of aperture and transmissivity in models that include a stochastic term are also the same. We observe that adopting a correlation between a fracture size and its transmissivity leads to earlier breakthrough times and higher effective permeability when compared to networks where no correlation is used. While fracture network geometry plays the principal role in determining where transport occurs within the network, the relationship between size and transmissivity controls the flow speed. These observations indicate DFN modelers should be aware that breakthrough times and effective permeabilities can be strongly influenced by such a relationship in addition to fracture and network statistics.

Fracture size and transmissivity correlations: Implications for transport simulations in sparse three-dimensional discrete fracture networks following a truncated power law distribution of fracture size

NASA Astrophysics Data System (ADS)

Hyman, J.; Aldrich, G. A.; Viswanathan, H. S.; Makedonska, N.; Karra, S.

2016-12-01

We characterize how different fracture size-transmissivity relationships influence flow and transport simulations through sparse three-dimensional discrete fracture networks. Although it is generally accepted that there is a positive correlation between a fracture's size and its transmissivity/aperture, the functional form of that relationship remains a matter of debate. Relationships that assume perfect correlation, semi-correlation, and non-correlation between the two have been proposed. To study the impact that adopting one of these relationships has on transport properties, we generate multiple sparse fracture networks composed of circular fractures whose radii follow a truncated power law distribution. The distribution of transmissivities are selected so that the mean transmissivity of the fracture networks are the same and the distributions of aperture and transmissivity in models that include a stochastic term are also the same.We observe that adopting a correlation between a fracture size and its transmissivity leads to earlier breakthrough times and higher effective permeability when compared to networks where no correlation is used. While fracture network geometry plays the principal role in determining where transport occurs within the network, the relationship between size and transmissivity controls the flow speed. These observations indicate DFN modelers should be aware that breakthrough times and effective permeabilities can be strongly influenced by such a relationship in addition to fracture and network statistics.

Fracture size and transmissivity correlations: Implications for transport simulations in sparse three-dimensional discrete fracture networks following a truncated power law distribution of fracture size

DOE PAGES

Hyman, Jeffrey De'Haven; Aldrich, Garrett Allen; Viswanathan, Hari S.; ...

2016-08-01

We characterize how different fracture size-transmissivity relationships influence flow and transport simulations through sparse three-dimensional discrete fracture networks. Although it is generally accepted that there is a positive correlation between a fracture's size and its transmissivity/aperture, the functional form of that relationship remains a matter of debate. Relationships that assume perfect correlation, semicorrelation, and noncorrelation between the two have been proposed. To study the impact that adopting one of these relationships has on transport properties, we generate multiple sparse fracture networks composed of circular fractures whose radii follow a truncated power law distribution. The distribution of transmissivities are selected somore » that the mean transmissivity of the fracture networks are the same and the distributions of aperture and transmissivity in models that include a stochastic term are also the same. We observe that adopting a correlation between a fracture size and its transmissivity leads to earlier breakthrough times and higher effective permeability when compared to networks where no correlation is used. While fracture network geometry plays the principal role in determining where transport occurs within the network, the relationship between size and transmissivity controls the flow speed. Lastly, these observations indicate DFN modelers should be aware that breakthrough times and effective permeabilities can be strongly influenced by such a relationship in addition to fracture and network statistics.« less

Fracture size and transmissivity correlations: Implications for transport simulations in sparse three-dimensional discrete fracture networks following a truncated power law distribution of fracture size

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

Hyman, Jeffrey De'Haven; Aldrich, Garrett Allen; Viswanathan, Hari S.

We characterize how different fracture size-transmissivity relationships influence flow and transport simulations through sparse three-dimensional discrete fracture networks. Although it is generally accepted that there is a positive correlation between a fracture's size and its transmissivity/aperture, the functional form of that relationship remains a matter of debate. Relationships that assume perfect correlation, semicorrelation, and noncorrelation between the two have been proposed. To study the impact that adopting one of these relationships has on transport properties, we generate multiple sparse fracture networks composed of circular fractures whose radii follow a truncated power law distribution. The distribution of transmissivities are selected somore » that the mean transmissivity of the fracture networks are the same and the distributions of aperture and transmissivity in models that include a stochastic term are also the same. We observe that adopting a correlation between a fracture size and its transmissivity leads to earlier breakthrough times and higher effective permeability when compared to networks where no correlation is used. While fracture network geometry plays the principal role in determining where transport occurs within the network, the relationship between size and transmissivity controls the flow speed. Lastly, these observations indicate DFN modelers should be aware that breakthrough times and effective permeabilities can be strongly influenced by such a relationship in addition to fracture and network statistics.« less

Sensorless Control of Permanent Magnet Machine for NASA Flywheel Technology Development

NASA Technical Reports Server (NTRS)

Kenny, Barbara H.; Kascak, Peter E.

2002-01-01

This paper describes the position sensorless algorithms presently used in the motor control for the NASA "in-house" development work of the flywheel energy storage system. At zero and low speeds a signal injection technique, the self-sensing method, is used to determine rotor position. At higher speeds, an open loop estimate of the back EMF of the machine is made to determine the rotor position. At start up, the rotor is set to a known position by commanding dc into one of the phase windings. Experimental results up to 52,000 rpm are presented.

An overview of revised NASA safety standard 1740.14

NASA Technical Reports Server (NTRS)

Reynolds, Robert; Eichler, Peter; Johnson, Nicholas

1997-01-01

Following a broad review of the debris control guidelines outside of NASA and according to additional feedback on the guidelines from within NASA, revisions were made to the NASA safety standard 1740.14. The NASA policy to limit the generation of orbital debris on NASA missions, stated in the NASA management instruction 1700.8 and implemented in the form of the NASA safety standard (NSS) 1740.14 is described together with the revisions implemented. The overall direction of the guidelines is the same, but the details of many of the guidelines were changed, including: changes for tether programs and for the control of operational debris. The NASA will continue to review the guidelines as new measurements and improved models of the environment are obtained.

Roughness-Dominated Hydraulic Fracture Propagation

NASA Astrophysics Data System (ADS)

Garagash, D.

2015-12-01

Current understanding suggests that the energy to propagate a hydraulic fracture is defined by the viscous fluid pressure drop along the fracture channel, while the energy dissipation in the immediate vicinity of the fracture front (i.e. fracture toughness) is negligible. This status quo relies on the assumption of Poiseuille flow in the fracture, which transmissivity varies as cube of the aperture. We re-evaluate this assumption in the vicinity of the fracture tip, where the aperture roughness and/or branching of the fracture path may lead to very significant deviations from the cubic law. Existing relationships suggest rough fracture transmissivity power laws ~ wr with 4.5 ≤ r ≤ 6, when aperture w is smaller than the roughness. Solving for the tip region of a steadily propagating hydraulic fracture with the "rough fracture" transmissivity, we are able to show (a) larger energy dissipation than predicted by the Poiseuille flow model; (b) localization of the fluid pressure drop into the low-transmissivity, rough tip region; and (c) emergence of potentially preeminent "toughness-dominated" fracture propagation regime where most of the energy is dissipated at the tip and can be described in the context of classical fracture mechanics by invoking the effective fracture toughness dependent upon the details of the pressure drop in the rough tip. We establish that the ratio of the roughness scale wc to the viscous aperture scale wμ = μVE / σ02, controls the pressure drop localization. (Here V - propagation speed, μ - fluid viscosity, E - rock modulus, and σ0 - in-situ stress). For a range of industrial fracturing fluids (from slick-water to linear gels) and treatment conditions, wc/wμ is large, suggesting a fully-localized pressure drop and energy dissipation. The latter is adequately described by the effective toughness - a function of the propagation velocity, confining stress and material parameters, which estimated values are much larger than the "dry" rock

Femoral neck shaft angle in men with fragility fractures.

PubMed

Tuck, S P; Rawlings, D J; Scane, A C; Pande, I; Summers, G D; Woolf, A D; Francis, R M

2011-01-01

Introduction. Femoral neck shaft angle (NSA) has been reported to be an independent predictor of hip fracture risk in men. We aimed to assess the role of NSA in UK men. Methods. The NSA was measured manually from the DXA scan printout in men with hip (62, 31 femoral neck and 31 trochanteric), symptomatic vertebral (91), and distal forearm (67) fractures and 389 age-matched control subjects. Age, height, weight, and BMD (g/cm(2): lumbar spine, femoral neck, and total femur) measurements were performed. Results. There was no significant difference in mean NSA between men with femoral neck and trochanteric hip fractures, so all further analyses of hip fractures utilised the combined data. There was no difference in NSA between those with hip fractures and those without (either using the combined data or analysing trochanteric and femoral neck shaft fractures separately), nor between fracture subjects as a whole and controls. Mean NSA was smaller in those with vertebral fractures (129.2° versus 131°: P = 0.001), but larger in those with distal forearm fractures (129.8° versus 128.5°: P = 0.01). Conclusions. The conflicting results suggest that femoral NSA is not an important determinant of hip fracture risk in UK men.

[Is Mapuche ethnicity a risk factor for hip fracture in aged?].

PubMed

Sapunar, Jorge; Bravo, Paulina; Schneider, Hermann; Jiménez, Marcela

2003-10-01

Ethnic factors are involved in the risk for osteoporosis and hip fracture. To assess the effect of Mapuche ethnicity on the risk of hip fracture. A case control study. Cases were subjects over 55 years of age admitted, during one year, for hip fracture not associated to major trauma or tumors. Controls were randomly chosen from other hospital services and paired for age with cases. The magnitude of the association between ethnicity and hip fracture was expressed as odds ratio in a logistic regression model. In the study period, 156 cases with hip fracture were admitted. The proportion of subjects with Mapuche origin was significantly lower among cases than controls (11.8 and 26.5% respectively, p < 0.001). In the logistic regression model, Mapuche ethnicity was associated with hip fracture with an odds radio of 0.14 (p = 0.03, 95% CI 0.03-0.8). In this sample, Mapuche ethnicity is a protective factor for hip fracture.

Flight Test of an Adaptive Controller and Simulated Failure/Damage on the NASA NF-15B

NASA Technical Reports Server (NTRS)

Buschbacher, Mark; Maliska, Heather

2006-01-01

The method of flight-testing the Intelligent Flight Control System (IFCS) Second Generation (Gen-2) project on the NASA NF-15B is herein described. The Gen-2 project objective includes flight-testing a dynamic inversion controller augmented by a direct adaptive neural network to demonstrate performance improvements in the presence of simulated failure/damage. The Gen-2 objectives as implemented on the NASA NF-15B created challenges for software design, structural loading limitations, and flight test operations. Simulated failure/damage is introduced by modifying control surface commands, therefore requiring structural loads measurements. Flight-testing began with the validation of a structural loads model. Flight-testing of the Gen-2 controller continued, using test maneuvers designed in a sequenced approach. Success would clear the new controller with respect to dynamic response, simulated failure/damage, and with adaptation on and off. A handling qualities evaluation was conducted on the capability of the Gen-2 controller to restore aircraft response in the presence of a simulated failure/damage. Control room monitoring of loads sensors, flight dynamics, and controller adaptation, in addition to postflight data comparison to the simulation, ensured a safe methodology of buildup testing. Flight-testing continued without major incident to accomplish the project objectives, successfully uncovering strengths and weaknesses of the Gen-2 control approach in flight.

Controlled Source Electromagnetic Monitoring of Hydraulic Fracturing: Wellbore and Fluid Effects

NASA Astrophysics Data System (ADS)

Couchman, M. J.; Everett, M. E.

2017-12-01

As unconventional resources become increasingly important, we must tackle the issue of real-time monitoring of the efficiency of unconventional hydrocarbon extraction. Controlled Source Electromagnetics (CSEM) have been used primarily as a marine-based technique to monitor conventional oil bearing reservoirs with a strong resurgence the new millennium. Many of these studies revolving around detecting a thin resistive layer such as a reservoir at 1m - 3km depth. In these cases, the presence of the resistive layer is characterized by a jump in electric field amplitude recorded at the boundary between the layer and the host sediments. The lessons learned from these studies can be applied to terrestrial unconventional settings with appropriate modifications. The work shown here is a means develop methods which enable more reliable terrestrial CSEM monitoring of the flow of injected fluids associated with hydraulic fracturing of unconventional reservoirs and to detect subsurface fluids based on their CSEM signature and in turn, to infer the subsurface flow of electrically conductive injected fluids. The predictive model validated for various 1-D marine, and terrestrial cases focus on the mapping of fluid flow in from a horizontal wellbore in a uniform halfspace using an in-line Horizontal Electric Dipole (HED) with electric field amplitude recorded by an array of electric field sensors. The effect of the of the vertical and horizontal wellbores are documented taking into account the conductivity, size, and thickness of each wellbore. The fracturing fluids flow and conductivity are also taken into account throughout various stages of the fracturing process. In each case, the sensitivity at a location of the surface in-line electric field to a given resistive or conductive layer, due to a source is calculated.

Discrete fracture modeling of multiphase flow and hydrocarbon production in fractured shale or low permeability reservoirs

NASA Astrophysics Data System (ADS)

Hao, Y.; Settgast, R. R.; Fu, P.; Tompson, A. F. B.; Morris, J.; Ryerson, F. J.

2016-12-01

It has long been recognized that multiphase flow and transport in fractured porous media is very important for various subsurface applications. Hydrocarbon fluid flow and production from hydraulically fractured shale reservoirs is an important and complicated example of multiphase flow in fractured formations. The combination of horizontal drilling and hydraulic fracturing is able to create extensive fracture networks in low permeability shale rocks, leading to increased formation permeability and enhanced hydrocarbon production. However, unconventional wells experience a much faster production decline than conventional hydrocarbon recovery. Maintaining sustainable and economically viable shale gas/oil production requires additional wells and re-fracturing. Excessive fracturing fluid loss during hydraulic fracturing operations may also drive up operation costs and raise potential environmental concerns. Understanding and modeling processes that contribute to decreasing productivity and fracturing fluid loss represent a critical component for unconventional hydrocarbon recovery analysis. Towards this effort we develop a discrete fracture model (DFM) in GEOS (LLNL multi-physics computational code) to simulate multiphase flow and transfer in hydraulically fractured reservoirs. The DFM model is able to explicitly account for both individual fractures and their surrounding rocks, therefore allowing for an accurate prediction of impacts of fracture-matrix interactions on hydrocarbon production. We apply the DFM model to simulate three-phase (water, oil, and gas) flow behaviors in fractured shale rocks as a result of different hydraulic stimulation scenarios. Numerical results show that multiphase flow behaviors at the fracture-matrix interface play a major role in controlling both hydrocarbon production and fracturing fluid recovery rates. The DFM model developed in this study will be coupled with the existing hydro-fracture model to provide a fully integrated

Evolution of Friction and Permeability in a Propped Fracture under Shear

DOE PAGES

Zhang, Fengshou; Fang, Yi; Elsworth, Derek; ...

2017-12-04

We explore the evolution of friction and permeability of a propped fracture under shear. We examine the effects of normal stress, proppant thickness, proppant size, and fracture wall texture on the frictional and transport response of proppant packs confined between planar fracture surfaces. The proppant-absent and proppant-filled fractures show different frictional strength. For fractures with proppants, the frictional response is mainly controlled by the normal stress and proppant thickness. The depth of shearing-concurrent striations on fracture surfaces suggests that the magnitude of proppant embedment is controlled by the applied normal stress. Under high normal stress, the reduced friction implies thatmore » shear slip is more likely to occur on propped fractures in deeper reservoirs. The increase in the number of proppant layers, from monolayer to triple layers, significantly increases the friction of the propped fracture due to the interlocking of the particles and jamming. Permeability of the propped fracture is mainly controlled by the magnitude of the normal stress, the proppant thickness, and the proppant grain size. Permeability of the propped fracture decreases during shearing due to proppant particle crushing and related clogging. Proppants are prone to crushing if the shear loading evolves concurrently with the normal loading.« less

Evolution of Friction and Permeability in a Propped Fracture under Shear

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

Zhang, Fengshou; Fang, Yi; Elsworth, Derek

We explore the evolution of friction and permeability of a propped fracture under shear. We examine the effects of normal stress, proppant thickness, proppant size, and fracture wall texture on the frictional and transport response of proppant packs confined between planar fracture surfaces. The proppant-absent and proppant-filled fractures show different frictional strength. For fractures with proppants, the frictional response is mainly controlled by the normal stress and proppant thickness. The depth of shearing-concurrent striations on fracture surfaces suggests that the magnitude of proppant embedment is controlled by the applied normal stress. Under high normal stress, the reduced friction implies thatmore » shear slip is more likely to occur on propped fractures in deeper reservoirs. The increase in the number of proppant layers, from monolayer to triple layers, significantly increases the friction of the propped fracture due to the interlocking of the particles and jamming. Permeability of the propped fracture is mainly controlled by the magnitude of the normal stress, the proppant thickness, and the proppant grain size. Permeability of the propped fracture decreases during shearing due to proppant particle crushing and related clogging. Proppants are prone to crushing if the shear loading evolves concurrently with the normal loading.« less

Automatic control of NASA Langley's 0.3-meter cryogenic test facility

NASA Technical Reports Server (NTRS)

Thibodeaux, J. J.; Balakrishna, S.

1980-01-01

Experience during the past 6 years of operation of the 0.3-meter transonic cryogenic tunnel at the NASA Langley Research Center has shown that there are problems associated with efficient operation and control of cryogenic tunnels using manual control schemes. This is due to the high degree of process crosscoupling between the independent control variables (temperature, pressure, and fan drive speed) and the desired test condition (Mach number and Reynolds number). One problem has been the inability to maintain long-term accurate control of the test parameters. Additionally, the time required to change from one test condition to another has proven to be excessively long and much less efficient than desirable in terms of liquid nitrogen and electrical power usage. For these reasons, studies have been undertaken to: (1) develop and validate a mathematical model of the 0.3-meter cryogenic tunnel process, (2) utilize this model in a hybrid computer simulation to design temperature and pressure feedback control laws, and (3) evaluate the adequacy of these control schemes by analysis of closed-loop experimental data. This paper will present the results of these studies.

Numerical simulation on ferrofluid flow in fractured porous media based on discrete-fracture model

NASA Astrophysics Data System (ADS)

Huang, Tao; Yao, Jun; Huang, Zhaoqin; Yin, Xiaolong; Xie, Haojun; Zhang, Jianguang

2017-06-01

Water flooding is an efficient approach to maintain reservoir pressure and has been widely used to enhance oil recovery. However, preferential water pathways such as fractures can significantly decrease the sweep efficiency. Therefore, the utilization ratio of injected water is seriously affected. How to develop new flooding technology to further improve the oil recovery in this situation is a pressing problem. For the past few years, controllable ferrofluid has caused the extensive concern in oil industry as a new functional material. In the presence of a gradient in the magnetic field strength, a magnetic body force is produced on the ferrofluid so that the attractive magnetic forces allow the ferrofluid to be manipulated to flow in any desired direction through the control of the external magnetic field. In view of these properties, the potential application of using the ferrofluid as a new kind of displacing fluid for flooding in fractured porous media is been studied in this paper for the first time. Considering the physical process of the mobilization of ferrofluid through porous media by arrangement of strong external magnetic fields, the magnetic body force was introduced into the Darcy equation and deals with fractures based on the discrete-fracture model. The fully implicit finite volume method is used to solve mathematical model and the validity and accuracy of numerical simulation, which is demonstrated through an experiment with ferrofluid flowing in a single fractured oil-saturated sand in a 2-D horizontal cell. At last, the water flooding and ferrofluid flooding in a complex fractured porous media have been studied. The results showed that the ferrofluid can be manipulated to flow in desired direction through control of the external magnetic field, so that using ferrofluid for flooding can raise the scope of the whole displacement. As a consequence, the oil recovery has been greatly improved in comparison to water flooding. Thus, the ferrofluid

NASA Bioreactor

NASA Technical Reports Server (NTRS)

1996-01-01

Close-up view of the interior of a NASA Bioreactor shows the plastic plumbing and valves (cylinders at center) to control fluid flow. A fresh nutrient bag is installed at top; a flattened waste bag behind it will fill as the nutrients are consumed during the course of operation. The drive chain and gears for the rotating wall vessel are visible at bottom center center. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators.

Rib Fracture Fixation: Indications and Outcomes.

PubMed

Senekjian, Lara; Nirula, Raminder

2017-01-01

Rib fractures are a frequently identified injury in the trauma population. Not only are multiple rib fractures painful, but they are associated with an increased risk of adverse outcomes. Pneumonia in particular can be devastating, especially to an elderly patient, but other complications such as prolonged ventilation and increased intensive care and hospital durations of stay have a negative impact on the patient. Computed tomography scan is the best modality to diagnosis rib fractures but the treatment of fractures is still evolving. Currently patient care involves a multidisciplinary approach that includes pain control, aggressive pulmonary therapy, and possibly surgical fixation. Copyright © 2016 Elsevier Inc. All rights reserved.

Fracture line morphology of complex proximal humeral fractures.

PubMed

Hasan, Afsana P; Phadnis, Joideep; Jaarsma, Ruurd L; Bain, Gregory I

2017-10-01

The aim of this study was to assess proximal humeral fracture patterns using 3-dimensional computed tomography images and relate them to the normal osseous landmarks and soft-tissue attachments. Forty-eight 3-dimensional computed tomography scans of proximal humeral fractures were retrospectively collected, and the fractures were transcribed onto proximal humeral templates. We analyzed the common location and orientation of the fracture lines, with a focus on fractures of the articular surface, tuberosities, metaphysis, and proximal diaphysis. These fractures were compared with the attachments of the rotator cuff and glenohumeral capsule. Fifty-two percent of the fractures involved the articular surface. No fractures passed through the bicipital groove, and fractures were more commonly found on the posterior lesser tuberosity and on the anterior greater tuberosity, coinciding with the intervals between the rotator cuff tendon insertions. Intracapsular fractures of the calcar were more common (68%) than extracapsular fractures (32%). On the anterolateral aspect of the proximal humerus, fractures radiated from the articular margin, vertically down through the tuberosity zone between the rotator cuff footprints, meeting horizontally oriented fractures in the metaphyseal zone. On the posterior aspect, vertical fractures from the tuberosity zone continued downward to the metaphyseal zone adjacent to the infraspinatus and teres minor footprints. Fractures of the proximal humerus follow characteristic patterns. Fractures frequently split the greater tuberosity and are closely related to the intervals of the rotator cuff attachments. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Risk of bone fractures associated with glucagon-like peptide-1 receptor agonists' treatment: a meta-analysis of randomized controlled trials.

PubMed

Su, Bin; Sheng, Hui; Zhang, Manna; Bu, Le; Yang, Peng; Li, Liang; Li, Fei; Sheng, Chunjun; Han, Yuqi; Qu, Shen; Wang, Jiying

2015-02-01

Traditional anti-diabetic drugs may have negative or positive effects on risk of bone fractures. Yet the relationship between the new class glucagon-like peptide-1 receptor agonists (GLP-1 RA) and risk of bone fractures has not been established. We performed a meta-analysis including randomized controlled trials (RCT) to study the risk of bone fractures associated with liraglutide or exenatide, compared to placebo or other active drugs. We searched MEDLINE, EMBASE, and clinical trial registration websites for published or unpublished RCTs comparing the effects of liraglutide or exenatide with comparators. Only studies with disclosed bone fracture data were included. Separate pooled analysis was performed for liraglutide or exenatide, respectively, by calculating Mantel-Haenszel odds ratio (MH-OR). 16 RCTs were identified including a total of 11,206 patients. Liraglutide treatment was associated with a significant reduced risk of incident bone fractures (MH-OR=0.38, 95% CI 0.17-0.87); however, exenatide treatment was associated with an elevated risk of incident bone fractures (MH-OR=2.09, 95% CI 1.03-4.21). Publication bias and heterogeneity between studies were not observed. Our study demonstrated a divergent risk of bone fractures associated with different GLP-1 RA treatments. The current findings need to be confirmed by future well-designed prospective or RCT studies.

Influence of natural fractures on hydraulic fracture propagation

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

Teufel, L.W.; Warpinski, N.R.

Hydraulic fracturing has become a valuable technique for the stimulation of oil, gas, and geothermal reservoirs in a variety of reservoir rocks. In many applications, only short fractures are needed for economic production. In low-permeability reservoirs, however, long penetrating fractures are generally needed, and in this case, natural fractures can be the cause of many adverse effects during a fracture treatment. Natural fractures can influence the overall geometry and effectiveness of the hydraulic fracture by: (1) arresting the vertical or lateral growth, (2) reducing total fracture length via fluid leakoff, (3) limiting proppant transport and placement, and (4) enhancing themore » creation of multiple or secondary fractures rather than a single planar hydraulic fracture. The result may range from negligible to catastrophic depending on the values of the ancillary treatment and reservoir parameters, such as the treating pressure, in-situ stresses, pore pressure, orientations of the natural fractures relative to principal in-situ stresses, spacing and distribution of the natural fractures, permeability, etc. Field observations from mineback experiments at DOE's Nevada Test Site and the multiwell experiment in Colorado, laboratory tests, and analyses of these data are integrated to describe the complex fracture behavior found and to provide guidelines for predicting when this complex fracturing will occur.« less

Influence of natural fractures on hydraulic fracture propagation

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

Teufel, L.W.; Warpinski, N.R.

Hydraulic fracturing has become a valuable technique for the stimulation of oil, gas, and geothermal reservoirs in a variety of reservoir rocks. In many applications, only short fractures are needed for economic production. In low-permeability reservoirs, however, long penetrating fractures are generally needed, and in this case, natural fractures can be the cause of many adverse effects during a fracture treatment. Natural fractures can influence the overall geometry and effectiveness of the hydraulic fracture by: (1) arresting the vertical or lateral growth, (2) reducing total fracture length via fluid leakoff, (3) limiting proppant transport and placement, and (4) enhancing themore » creation of multiple or secondary fractures rather than a single planar hydraulic fracture. The result may range from negligible to catastrophic depending on the values of the ancillary treatment and reservoir parameters, such as the treating pressure, in-situ stresses, pore pressure, orientations of the natural fractures relative to principle in-situ stresses, spacing and distribution of the natural fractures, permeability, etc. Field observations from mineback experiments at DOE's Nevada Test Site and the multiwell experiment in Colorado, laboratory tests, and analyses of these data are integrated to describe the complex fracture behavior found to an provide guidelines for predicting when this complex fracturing occurs.« less

Advanced aerodynamics. Selected NASA research

NASA Technical Reports Server (NTRS)

1981-01-01

This Conference Publication contains selected NASA papers that were presented at the Fifth Annual Status Review of the NASA Aircraft Energy Efficiency (ACEE) Energy Efficient Transport (EET) Program held at Dryden Flight Research Center in Edwards, California on September 14 to 15, 1981. These papers describe the status of several NASA in-house research activities in the areas of advanced turboprops, natural laminar flow, oscillating control surfaces, high-Reynolds-number airfoil tests, high-lift technology, and theoretical design techniques.

The Extravehicular Suit Impact Load Attenuation Study for Use in Astronaut Bone Fracture Prediction

NASA Technical Reports Server (NTRS)

Lewandowski, Beth E.; Gilkey, Kelly M.; Sulkowski, Christina M.; Samorezov, Sergey; Myers, Jerry G.

2011-01-01

The NASA Integrated Medical Model (IMM) assesses the risk, including likelihood and impact of occurrence, of all credible in-flight medical conditions. Fracture of the proximal femur is a traumatic injury that would likely result in loss of mission if it were to happen during spaceflight. The low gravity exposure causes decreases in bone mineral density which heightens the concern. Researchers at the NASA Glenn Research Center have quantified bone fracture probability during spaceflight with a probabilistic model. It was assumed that a pressurized extravehicular activity (EVA) suit would attenuate load during a fall, but no supporting data was available. The suit impact load attenuation study was performed to collect analogous data. METHODS: A pressurized EVA suit analog test bed was used to study how the offset, defined as the gap between the suit and the astronaut s body, impact load magnitude and suit operating pressure affects the attenuation of impact load. The attenuation data was incorporated into the probabilistic model of bone fracture as a function of these factors, replacing a load attenuation value based on commercial hip protectors. RESULTS: Load attenuation was more dependent on offset than on pressurization or load magnitude, especially at small offsets. Load attenuation factors for offsets between 0.1 - 1.5 cm were 0.69 +/- 0.15, 0.49 +/- 0.22 and 0.35 +/- 0.18 for mean impact forces of 4827, 6400 and 8467 N, respectively. Load attenuation factors for offsets of 2.8 - 5.3 cm were 0.93 +/- 0.2, 0.94 +/- 0.1 and 0.84 +/- 0.5, for the same mean impact forces. Reductions were observed in the 95th percentile confidence interval of the bone fracture probability predictions. CONCLUSIONS: The reduction in uncertainty and improved confidence in bone fracture predictions increased the fidelity and credibility of the fracture risk model and its benefit to mission design and operational decisions.

Effects of a home-based physical rehabilitation program on physical disability after hip fracture: a randomized controlled trial.

PubMed

Edgren, Johanna; Salpakoski, Anu; Sihvonen, Sanna E; Portegijs, Erja; Kallinen, Mauri; Arkela, Marja; Jäntti, Pirkko; Vanhatalo, Jukka; Pekkonen, Mika; Rantanen, Taina; Heinonen, Ari; Sipilä, Sarianna

2015-04-01

Fewer than half of the patients with hip fracture will regain the prefracture level of physical functioning. This secondary analysis of a randomized controlled trial investigated the effects of a multicomponent home-based rehabilitation program (ProMo) on physical disability after hip fracture. Randomized, controlled, parallel-group trial. Rehabilitation in participants' homes; measurements in university-based laboratory and local hospital. Population-based clinical sample of community-dwelling people older than 60 years (n = 81) operated for hip fracture were randomized into intervention and control groups. The year-long intervention aimed at restoring mobility. It included evaluation and modification of environmental hazards, guidance for safe walking, pain management, home exercise, physical activity counseling, and standard care. Physical disability was assessed by a questionnaire at baseline, and 3, 6, and 12 months thereafter. Sum scores were computed for basic (ADLs) and instrumental activities of daily living (IADLs). A higher score indicated more difficulty. GEE models were constructed to analyze the effect of the intervention. In the intention-to-treat analysis, no intervention effect was observed for sum scores. For the single disability items, borderline significant positive effects were observed for preparing food and handling medication (interaction P = .061 and P = .061, respectively). In the per-protocol analysis, the mean differences between groups were -0.4 points (SE 0.5), -1.7 (0.7), and -1.2 (0.7) at 3, 6, and 12 months for ADLs and -1.0 (1.2), -3.2 (1.5), and -2.5 (1.4) for IADLs, correspondingly. The current analyses suggest that home-based rehabilitation may reduce disability among older people after hip fracture. The present results need to be confirmed in a study with larger sample size. Potentially a more task-oriented rehabilitation approach might gain more benefits. Current Controlled Trials (ISRCTN53680197). Copyright © 2015 AMDA �

The Effect of fluid buoyancy and fracture orientation on CaCO3 Formation in a Fracture

NASA Astrophysics Data System (ADS)

Xu, Z.; Li, Q.; Sheets, J.; Kneafsey, T. J.; Jun, Y. S.; Cole, D. R.; Pyrak-Nolte, L. J.

2016-12-01

fracture enabled more mixing of the two solutions within the fracture than the vertical fracture. This work was supported by the Center for Nanoscale Controls on Geologic CO (NCGC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-AC02-05CH11231

High prevalence of radiological vertebral fractures in HIV-infected males.

PubMed

Torti, Carlo; Mazziotti, Gherardo; Soldini, Pier Antonio; Focà, Emanuele; Maroldi, Roberto; Gotti, Daria; Carosi, Giampiero; Giustina, Andrea

2012-06-01

Age-related co-morbidities including osteoporosis are relevant in patients responding to combination antiretroviral therapy (cART). Vertebral fractures are common osteoporotic fractures and their diagnosis is useful for managing at-risk individuals. However, there are few data from HIV-infected patients. Therefore, the aim of this study was to determine the prevalence of and factors associated with vertebral fractures in a population of HIV-infected males. A cross-sectional study of 160 HIV-infected patients with available chest X-rays was conducted from 1998 to 2010. One hundred and sixty-three males with comparable age and with no history of HIV infection were recruited as controls. Semi-quantitative evaluation of vertebral heights in lateral chest X-rays and quantitative morphometry assessment of centrally digitized images using dedicated morphometry software were utilized to detect prevalent vertebral fractures. The result showed that the vertebral fractures were detected in 43/160 (26.9%) HIV-infected patients and in 21/163 (12.9%) controls (P = 0.002). In HIV-infected patients with fractures, 27 had two or more fractures and ten patients had severe fractures. The prevalence of any fractures and multiple fractures in HIV-infected patients receiving cART (29.6 and 20.0%) was slightly higher than in HIV-infected patients not exposed to cART (17.1 and 5.7%), but significantly higher than control subjects (12.9 and 3.7%). At multivariable analyses, body mass index and diabetes mellitus were independently correlated with vertebral fractures in HIV-infected patients. We concluded that a significant proportion of HIV-infected males receiving cART showed vertebral fractures. Furthermore, proactive diagnosis of vertebral fragility fractures is particularly relevant in patients who are overweight or suffer from diabetes.

Intramedullary nailing of humeral shaft fractures.

PubMed

Pickering, Robert M; Crenshaw, Andrew H; Zinar, Daniel M

2002-01-01

The development of interlocking humeral nail systems has greatly broadened the indications for nailing of humeral shaft fracture. Rotational control is better than with earlier nail systems, and most nails have an oblong distal hole that allows axial loading of the fracture site with muscle contraction. When nailing is done with closed technique, loss of the fracture hematoma and periosteal stripping are avoided. Even when open reduction is required, periosteal stripping can be kept to a minimum. Surgical wounds are smaller, even when open reduction is necessary, and when closed nailing is done, bone grafting is unnecessary. Intramedullary nails are ideal for segmental fractures, pathologic fractures, and fractures in osteopenic bone. Because the arm usually is not a weight-bearing extremity, hardware failure is rare and union rates are equivalent to those of compression plate and screw fixation. Compression plates and external fixation certainly have their place for some fracture patterns and for severe wounds that are unsuitable for intramedullary nailing. The surgeon should be well versed in all three techniques and should be able to rapidly choose among these, depending upon the fracture pattern, skin wound, associated injuries, and overall condition of the patient.

NASA/NBS (National Aeronautics and Space Administration/National Bureau of Standards) standard reference model for telerobot control system architecture (NASREM)

NASA Technical Reports Server (NTRS)

Albus, James S.; Mccain, Harry G.; Lumia, Ronald

1989-01-01

The document describes the NASA Standard Reference Model (NASREM) Architecture for the Space Station Telerobot Control System. It defines the functional requirements and high level specifications of the control system for the NASA space Station document for the functional specification, and a guideline for the development of the control system architecture, of the 10C Flight Telerobot Servicer. The NASREM telerobot control system architecture defines a set of standard modules and interfaces which facilitates software design, development, validation, and test, and make possible the integration of telerobotics software from a wide variety of sources. Standard interfaces also provide the software hooks necessary to incrementally upgrade future Flight Telerobot Systems as new capabilities develop in computer science, robotics, and autonomous system control.

Validation of the Two-Parameter-Fracture Criterion for Various Crack Configurations Made of 2014-T6 (TL) Aluminum Alloy Using Finite Element Fracture Simulations

NASA Astrophysics Data System (ADS)

McQuilkin, Martin

The Two-Parameter- Fracture-Criterion (TPFC) was validated using an elastic-plastic two-dimensional (2D) finite-element code, ZIP2D, with the plane-strain- core concept. Fracture simulations were performed on three crack configurations: (1) middle-crack-tension, M(T), (2) single-edge- crack-tension, SE(T), and (3) single-edge crack-bend, SE(B), specimens. They were made of 2014-T6 (TL) aluminum alloy. Fracture test data from Thomas Orange work (NASA) were only available on M(T) specimens (one-half width, w = 1.5 to 6 in.) and they were all tested at cryogenic (-320 o F) temperature. All crack configurations were analysed over a very wide range of widths (w = 0.75 to 24 in.) and crack-length- to-width ratios ranged from 0.2 to 0.8. The TPFC was shown to fit the simulated fracture data fairly well (within 6.5%) for all crack configurations for net-section stresses less than the material proportional limit. For M(T) specimens, a simple approximation was shown to work well for net-section stresses greater than the proportional limit. Further study is needed for net-section stresses greater than the proportional limit for the SE(T) and SE(B) specimens.

NASA's Controlled Environment Agriculture Testing for Space Habitats

NASA Technical Reports Server (NTRS)

Wheeler, Raymond M.

2014-01-01

NASA and other space agencies have an interest in using plants for human life support in space. The plants could provide food and O2 for the humans, while removing CO2 and helping purify wastewater. Studies to date have shown that a wide range of crops can be grown in controlled environment conditions envisioned for space. Light is a critical factor both for crop productivity and system power costs, and recent improvements in LEDs make them a preferred lighting option for space. Because space systems would be tightly closed, issues such as ethylene build-up and management must be considered. Ultimately, the costs and reliability of biological life support options must be compared with more conventional life support approaches. Findings to date suggest that about 20-25 sq. meters of crops could supply the O2 for one human, while about 50 sq. meters would be required for food (dietary calories).

Fluid transport in reaction induced fractures

NASA Astrophysics Data System (ADS)

Ulven, Ole Ivar; Sun, WaiChing; Malthe-Sørenssen, Anders

2015-04-01

The process of fracture formation due to a volume increasing chemical reaction has been studied in a variety of different settings, e.g. weathering of dolerites by Røyne et al. te{royne}, serpentinization and carbonation of peridotite by Rudge et al. te{rudge} and replacement reactions in silica-poor igneous rocks by Jamtveit et al. te{jamtveit}. It is generally assumed that fracture formation will increase the net permeability of the rock, and thus increase the reactant transport rate and subsequently the total rate of material conversion, as summarised by Kelemen et al. te{kelemen}. Ulven et al. te{ulven_1} have shown that for fluid-mediated processes the ratio between chemical reaction rate and fluid transport rate in bulk rock controls the fracture pattern formed, and Ulven et al. te{ulven_2} have shown that instantaneous fluid transport in fractures lead to a significant increase in the total rate of the volume expanding process. However, instantaneous fluid transport in fractures is clearly an overestimate, and achievable fluid transport rates in fractures have apparently not been studied in any detail. Fractures cutting through an entire domain might experience relatively fast advective reactant transport, whereas dead-end fractures will be limited to diffusion of reactants in the fluid, internal fluid mixing in the fracture or capillary flow into newly formed fractures. Understanding the feedback process between fracture formation and permeability changes is essential in assessing industrial scale CO2 sequestration in ultramafic rock, but little is seemingly known about how large the permeability change will be in reaction-induced fracturing. In this work, we study the feedback between fracture formation during volume expansion and fluid transport in different fracture settings. We combine a discrete element model (DEM) describing a volume expanding process and the related fracture formation with different models that describe the fluid transport in the

Comprehensive geriatric care for patients with hip fractures: a prospective, randomised, controlled trial.

PubMed

Prestmo, Anders; Hagen, Gunhild; Sletvold, Olav; Helbostad, Jorunn L; Thingstad, Pernille; Taraldsen, Kristin; Lydersen, Stian; Halsteinli, Vidar; Saltnes, Turi; Lamb, Sarah E; Johnsen, Lars G; Saltvedt, Ingvild

2015-04-25

Most patients with hip fractures are characterised by older age (>70 years), frailty, and functional deterioration, and their long-term outcomes are poor with increased costs. We compared the effectiveness and cost-effectiveness of giving these patients comprehensive geriatric care in a dedicated geriatric ward versus the usual orthopaedic care. We did a prospective, single-centre, randomised, parallel-group, controlled trial. Between April 18, 2008, and Dec 30, 2010, we randomly assigned home-dwelling patients with hip-fractures aged 70 years or older who were able to walk 10 m before their fracture, to either comprehensive geriatric care or orthopaedic care in the emergency department, to achieve the required sample of 400 patients. Randomisation was achieved via a web-based, computer-generated, block method with unknown block sizes. The primary outcome, analysed by intention to treat, was mobility measured with the Short Physical Performance Battery (SPPB) 4 months after surgery for the fracture. The type of treatment was not concealed from the patients or staff delivering the care, and assessors were only partly masked to the treatment during follow-up. This trial is registered with ClinicalTrials.gov, number NCT00667914. We assessed 1077 patients for eligibility, and excluded 680, mainly for not meeting the inclusion criteria such as living in a nursing home or being aged less than 70 years. Of the remaining patients, we randomly assigned 198 to comprehensive geriatric care and 199 to orthopaedic care. At 4 months, 174 patients remained in the comprehensive geriatric care group and 170 in the orthopaedic care group; the main reason for dropout was death. Mean SPPB scores at 4 months were 5·12 (SE 0·20) for comprehensive geriatric care and 4·38 (SE 0·20) for orthopaedic care (between-group difference 0·74, 95% CI 0·18-1·30, p=0·010). Immediate admission of patients aged 70 years or more with a hip fracture to comprehensive geriatric care in a dedicated

A pragmatic randomised controlled trial of the effectiveness and cost-effectiveness of screening older women for the prevention of fractures: rationale, design and methods for the SCOOP study.

PubMed

Shepstone, L; Fordham, R; Lenaghan, E; Harvey, I; Cooper, C; Gittoes, N; Heawood, A; Peters, T J; O'Neill, T; Torgerson, D; Holland, R; Howe, A; Marshall, T; Kanis, J A; McCloskey, E

2012-10-01

SCOOP is a UK seven-centre, pragmatic, randomised controlled trial with 5-year follow-up, including 11,580 women aged 70 to 85 years, to assess the effectiveness and cost-effectiveness of a community-based screening programme to reduce fractures. It utilises the FRAX algorithm and DXA to assess the 10-year probability of fracture. Introduction Osteoporotic, or low-trauma, fractures present a considerable burden to the National Health Service and have major adverse effects on quality of life, disability and mortality for the individual. Methods Given the availability of efficacious treatments and a risk assessment tool based upon clinical risk factors and bone mineral density, a case exists to undertake a community-based controlled evaluation of screening for subjects at high risk of fracture, under the hypothesis that such a screening programme would reduce fractures in this population. Results This study is a UK seven-centre, unblinded, pragmatic, randomised controlled trial with a 5-year follow-up period. A total of 11,580 women, aged 70 to 85 years and not on prescribed bone protective therapy will be consented to the trial by post via primary care providing 90% power to detect an 18% decrease in fractures. Conclusions Participants will be randomised to either a screening arm or control. Those undergoing screening will have a 10-year fracture probability computed from baseline risk factors together with bone mineral density measured by DXA in selected subjects. Individuals above an age-dependent threshold of fracture probability will be recommended for treatment for the duration of the trial. Subjects in the control arm will receive 'usual care'. Participants will be followed up 6 months after randomisation and annually by postal questionnaires with independent checking of hospital and primary care records. The primary outcome will be the proportion of individuals sustaining fractures in each group. An economic analysis will be carried out to assess cost

Women with previous stress fractures show reduced bone material strength

PubMed Central

Duarte Sosa, Daysi; Fink Eriksen, Erik

2016-01-01

Background and purpose — Bone fragility is determined by bone mass, bone architecture, and the material properties of bone. Microindentation has been introduced as a measurement method that reflects bone material properties. The pathogenesis of underlying stress fractures, in particular the role of impaired bone material properties, is still poorly understood. Based on the hypothesis that impaired bone material strength might play a role in the development of stress fractures, we used microindentation in patients with stress fractures and in controls. Patients and methods — We measured bone material strength index (BMSi) by microindentation in 30 women with previous stress fractures and in 30 normal controls. Bone mineral density by DXA and levels of the bone markers C-terminal cross-linking telopeptide of type-1 collagen (CTX) and N-terminal propeptide of type-1 procollagen (P1NP) were also determined. Results — Mean BMSi in stress fracture patients was significantly lower than in the controls (SD 72 (8.7) vs. 77 (7.2); p = 0.02). The fracture subjects also had a significantly lower mean bone mineral density (BMD) than the controls (0.9 (0.02) vs. 1.0 (0.06); p = 0.03). Bone turnover—as reflected in serum levels of the bone marker CTX—was similar in both groups, while P1NP levels were significantly higher in the women with stress fractures (55 μg/L vs. 42 μg/L; p = 0.03). There was no correlation between BMSi and BMD or bone turnover. Interpretation — BMSi was inferior in patients with previous stress fracture, but was unrelated to BMD and bone turnover. The lower values of BMSi in patients with previous stress fracture combined with a lower BMD may contribute to the increased propensity to develop stress fractures in these patients. PMID:27321443

Range limitation in hip internal rotation and fifth metatarsal stress fractures (Jones fracture) in professional football players.

PubMed

Saita, Yoshitomo; Nagao, Masashi; Kawasaki, Takayuki; Kobayashi, Yohei; Kobayashi, Keiji; Nakajima, Hiroki; Takazawa, Yuji; Kaneko, Kazuo; Ikeda, Hiroshi

2017-04-25

To identify unknown risk factors associated with fifth metatarsal stress fracture (Jones fracture). A case-controlled study was conducted among male Japanese professional football (soccer) players with (N = 20) and without (N = 40) a history of Jones fracture. Injury history and physical examination data were reviewed, and the two groups were compared. Univariate and multivariate logistic regression controlling for age, leg dominance and body mass index were used to obtain odds ratios (ORs) and 95% confidence intervals (CIs) to describe the association between physical examination data and the presence or absence of Jones fractures. From 2000 to 2014, among 162 professional football club players, 22 (13.6%; 21 Asians and one Caucasian) had a history of Jones fracture. Thirteen out of 22 (60%) had a Jones fracture in their non-dominant leg. The mean range of hip internal rotation (HIR) was restricted in players with a history of Jones fracture [25.9° ± 7.5°, mean ± standard deviation (SD)] compared to those without (40.4° ± 11.1°, P < 0.0001). Logistic regression analyses demonstrated that HIR limitation increased the risk of a Jones fracture (OR = 3.03, 95% CI 1.45-6.33, P = 0.003). Subgroup analysis using data prior to Jones fracture revealed a causal relationship, such that players with a restriction of HIR were at high risk of developing a Jones fracture [Crude OR (95% CI) = 6.66 (1.90-23.29), P = 0.003, Adjusted OR = 9.91 (2.28-43.10), P = 0.002]. In addition, right HIR range limitation increased the risks of developing a Jones fracture in the ipsilateral and the contralateral feet [OR = 3.11 (1.35-7.16) and 2.24 (1.22-4.12), respectively]. Similarly, left HIR range limitation increased the risks in the ipsilateral or the contralateral feet [OR (95% CI) = 4.88 (1.56-15.28) and 2.77 (1.08-7.08), respectively]. The restriction of HIR was associated with an increased risk of developing a Jones fracture. Since the HIR range is a

Electrical, Electronic, and Electromechanical (EEE) parts management and control requirements for NASA space flight programs

NASA Technical Reports Server (NTRS)

1989-01-01

This document establishes electrical, electronic, and electromechanical (EEE) parts management and control requirements for contractors providing and maintaining space flight and mission-essential or critical ground support equipment for NASA space flight programs. Although the text is worded 'the contractor shall,' the requirements are also to be used by NASA Headquarters and field installations for developing program/project parts management and control requirements for in-house and contracted efforts. This document places increased emphasis on parts programs to ensure that reliability and quality are considered through adequate consideration of the selection, control, and application of parts. It is the intent of this document to identify disciplines that can be implemented to obtain reliable parts which meet mission needs. The parts management and control requirements described in this document are to be selectively applied, based on equipment class and mission needs. Individual equipment needs should be evaluated to determine the extent to which each requirement should be implemented on a procurement. Utilization of this document does not preclude the usage of other documents. The entire process of developing and implementing requirements is referred to as 'tailoring' the program for a specific project. Some factors that should be considered in this tailoring process include program phase, equipment category and criticality, equipment complexity, and mission requirements. Parts management and control requirements advocated by this document directly support the concept of 'reliability by design' and are an integral part of system reliability and maintainability. Achieving the required availability and mission success objectives during operation depends on the attention given reliability and maintainability in the design phase. Consequently, it is intended that the requirements described in this document are consistent with those of NASA publications

NASA researchers in gold control room during an F-15 HiDEC flight

NASA Technical Reports Server (NTRS)

1993-01-01

NASA researchers monitor equipment in the mission control Gold room at the Dryden Flight Research Center, Edwards, California, during a flight of an F-15 Highly Integrated Digital Electronic Control (HIDEC) research aircraft. The system was developed on the F-15 to investigate and demonstrate methods of obtaining optimum aircraft performance. The major elements of HIDEC were a Digital Electronic Flight Control System (DEFCS), a Digital Electronic Engine Control (DEEC), an on-board general purpose computer, and an integrated architecture to allow all components to 'talk to each other.' Unlike standard F-15s, which have a mechanical and analog electronic flight control system, the HIDEC F-15 also had a dual-channel, fail-safe digital flight control system programmed in Pascal. It was linked to the Military Standard 1553B and a H009 data bus which tied all the other electronic systems together.

What controls diffuse fractures in platform carbonates? Insights from Provence (France) and Apulia (Italy)

NASA Astrophysics Data System (ADS)

Lavenu, Arthur P. C.; Lamarche, Juliette

2018-03-01

Fractures are widespread in rocks and regional opening-mode arrays are commonly ascribed to major tectonic events. However, fractures occur in otherwise undeformed rocks. Some of these are early-developed features independent of tectonics and forming a background network at regional scale. To overcome this lack of understanding, two hydrocarbon reservoir analogues from platform carbonates have been targeted: the Provence (SE France), and the Apulian platform (SE Italy). In both areas, an early fracturing stage has been observed, made of high-angle-to-bedding opening-mode fractures, and bed-parallel stylolites. These features developed synchronously during the first burial stages and prior to major tectonic events. The fracture sets are not genetically related to the present-day layering. Contrarily, fractures developed in a brittle media where facies transitions were not sharp and did not act as mechanical discontinuities. Carbonate facies distribution and early diagenetic imprint constrained the mechanical stratigraphy when fractures occurred. In addition, we observed that fractures related to late tectonic inversion were partly inhibited. Indeed, rock mechanical properties change through time. Characterizing the temporal evolution of carbonate rocks has revealed that diagenesis and sedimentary facies are the prime actors for brittleness and mechanical layering in carbonates.

NASA Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Carter, David; Wetzel, Scott

2000-01-01

The NASA SLR Operational Center is responsible for: 1) NASA SLR network control, sustaining engineering, and logistics; 2) ILRS mission operations; and 3) ILRS and NASA SLR data operations. NASA SLR network control and sustaining engineering tasks include technical support, daily system performance monitoring, system scheduling, operator training, station status reporting, system relocation, logistics and support of the ILRS Networks and Engineering Working Group. These activities ensure the NASA SLR systems are meeting ILRS and NASA mission support requirements. ILRS mission operations tasks include mission planning, mission analysis, mission coordination, development of mission support plans, and support of the ILRS Missions Working Group. These activities ensure than new mission and campaign requirements are coordinated with the ILRS. Global Normal Points (NP) data, NASA SLR FullRate (FR) data, and satellite predictions are managed as part of data operations. Part of this operation includes supporting the ILRS Data Formats and Procedures Working Group. Global NP data operations consist of receipt, format and data integrity verification, archiving and merging. This activity culminates in the daily electronic transmission of NP files to the CDDIS. Currently of all these functions are automated. However, to ensure the timely and accurate flow of data, regular monitoring and maintenance of the operational software systems, computer systems and computer networking are performed. Tracking statistics between the stations and the data centers are compared periodically to eliminate lost data. Future activities in this area include sub-daily (i.e., hourly) NP data management, more stringent data integrity tests, and automatic station notification of format and data integrity issues.

Relationship between vitamin D, osteoporotic fracture and falls.

PubMed

Candel Romero, Carmen; Forner Cordero, Ángeles; Sánchez Santos, José Cristóbal; Pereiró Berenguer, Inmaculada

2017-11-22

Link low levels of vitamin D, osteoporotic fracture and falls. Transversal observational study with the study variables of age, levels of vitamin D, osteoporotic fracture and falls. The study population was patients evaluated by the Rehabilitation Department, Hospital of Sagunto, from January 2013 to December 2014. Of the 242 patients who underwent vitamin D analysis, 70.6% showed levels under 30ng/ml. Forty-eight percent of the patients with below normal levels of vitamin D suffered a fracture, opposed to 32.4% patients with normal levels. Thus, controlling by age, patients with low levels of vitamin D are 4.8 times more likely to suffer a fracture than those with normal levels. Regarding falls, controlling by age, there is a higher risk of falling (adjusted OR 2.68) in those patients with low levels of vitamin D. Patients with low vitamin D levels are more likely to suffer falls and fractures. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

Correlation of Hip Fracture with Other Fracture Types: Toward a Rational Composite Hip Fracture Endpoint

PubMed Central

Colón-Emeric, Cathleen; Pieper, Carl F.; Grubber, Janet; Van Scoyoc, Lynn; Schnell, Merritt L; Van Houtven, Courtney Harold; Pearson, Megan; Lafleur, Joanne; Lyles, Kenneth W.; Adler, Robert A.

2016-01-01

Purpose With ethical requirements to the enrollment of lower risk subjects, osteoporosis trials are underpowered to detect reduction in hip fractures. Different skeletal sites have different levels of fracture risk and response to treatment. We sought to identify fracture sites which cluster with hip fracture at higher than expected frequency; if these sites respond to treatment similarly, then a composite fracture endpoint could provide a better estimate of hip fracture reduction. Methods Cohort study using Veterans Affairs and Medicare administrative data. Male Veterans (n=5,036,536) aged 50-99 years receiving VA primary care between1999-2009 were included. Fractures were ascertained using ICD9 and CPT codes and classified by skeletal site. Pearson correlation coefficients, logistic regression and kappa statistics, were used to describe the correlation between each fracture type and hip fracture within individuals, without regards to the timing of the events. Results 595,579 (11.8%) men suffered 1 or more fractures and 179,597 (3.6%) suffered 2 or more fractures during the time under study. Of those with one or more fractures, rib was the most common site (29%), followed by spine (22%), hip (21%) and femur (20%). The fracture types most highly correlated with hip fracture were pelvic/acetabular (Pearson correlation coefficient 0.25, p<0.0001), femur (0.15, p<0.0001), and shoulder (0.11, p<0.0001). Conclusions Pelvic, acetabular, femur, and shoulder fractures cluster with hip fractures within individuals at greater than expected frequency. If we observe similar treatment risk reductions within that cluster, subsequent trials could consider use of a composite endpoint to better estimate hip fracture risk. PMID:26151123

Flight test of a propulsion controlled aircraft system on the NASA F-15 airplane

NASA Technical Reports Server (NTRS)

Burcham, Frank W., Jr.; Maine, Trindel A.

1995-01-01

Flight tests of the propulsion controlled aircraft (PCA) system on the NASA F-15 airplane evolved as a result of a long series of simulation and flight tests. Initially, the simulation results were very optimistic. Early flight tests showed that manual throttles-only control was much more difficult than the simulation, and a flight investigation was flown to acquire data to resolve this discrepancy. The PCA system designed and developed by MDA evolved as these discrepancies were found and resolved, requiring redesign of the PCA software and modification of the flight test plan. Small throttle step inputs were flown to provide data for analysis, simulation update, and control logic modification. The PCA flight tests quickly revealed less than desired performance, but the extensive flexibility built into the flight PCA software allowed rapid evaluation of alternate gains, filters, and control logic, and within 2 weeks, the PCA system was functioning well. The initial objective of achieving adequate control for up-and-away flying and approaches was satisfied, and the option to continue to actual landings was achieved. After the PCA landings were accomplished, other PCA features were added, and additional maneuvers beyond those originally planned were flown. The PCA system was used to recover from extreme upset conditions, descend, and make approaches to landing. A heading mode was added, and a single engine plus rudder PCA mode was also added and flown. The PCA flight envelope was expanded far beyond that originally designed for. Guest pilots from the USAF, USN, NASA, and the contractor also flew the PCA system and were favorably impressed.

Futurepath: The Story of Research and Technology at NASA Lewis Research Center. Structures for Flight Propulsion, ARC Sprayed Monotape, National Aero-Space Plane

NASA Technical Reports Server (NTRS)

1989-01-01

The story of research and technology at NASA Lewis Research Center's Structures Division is presented. The job and designs of the Structures Division needed for flight propulsion is described including structural mechanics, structural dynamics, fatigue, and fracture. The video briefly explains why properties of metals used in structural mechanics need to be tested. Examples of tests and simulations used in structural dynamics (bodies in motion) are briefly described. Destructive and non-destructive fatigue/fracture analysis is also described. The arc sprayed monotape (a composite material) is explained, as are the programs in which monotape plays a roll. Finally, the National Aero-Space Plane (NASP or x-30) is introduced, including the material development and metal matrix as well as how NASP will reduce costs for NASA.

Characterizing Fractures Across the Astronaut Corps: Preliminary Findings from Population-Level Analysis

NASA Technical Reports Server (NTRS)

Rossi, Meredith M.; Charvat, Jacqueline; Sibonga, Jean; Sieker, Jeremy

2017-01-01

Despite evidence of bone loss during spaceflight and operational countermeasures to mitigate this loss, the subsequent risk of fracture among astronauts is not known. The physiologic process of diminished bone density and bone recovery during or following spaceflight is multifactorial. Such factors as age, sex, fracture history, and others may combine to increase fracture risk among astronauts. As part of the 2016 Bone Research and Clinical Advisory Panel (RCAP), the authors analyzed data collected on 338 NASA astronauts to describe the demographics, bone-relevant characteristics, and fracture history of the astronaut population. The majority of the population are male (n=286, 84.6%), have flown at least one mission (n=306, 90.5%), and were between the ages of 30 and 49 at first mission (n=296, 96.7% of those with at least one mission). Of the 338 astronauts, 241 (71.3%) experienced a fracture over the course of their lifetime. One hundred and five (43.5%) of these 241 astronauts only experienced a fracture prior to being selected into the Astronaut Corps, whereas 53 (22.0%) only experienced a fracture after selection as an astronaut. An additional 80 astronauts (33.2%) had both pre- and post-selection fractures. The remaining 3 astronauts had a fracture of unknown date, which could not be categorized as pre- or post-selection. Among the 133 astronauts with at least one post-selection fracture, males comprised 90.2% (n=120) compared to 84.5% of the entire Corps, and females accounted for 9.8% (n=13) compared to 15.4% of the Corps. Ninety-seven of the 133 astronauts with post-selection fractures (72.9%) had one fracture event, 22 (16.5%) had two fractures, and 14 (10.5%) had three or more fractures. Some astronauts with multiple fractures suffered these in a single event, such as an automobile accident. The 133 astronauts with a post-selection fracture accounted for a total of 188 fracture events. One hundred and four (78.2%) of astronauts with post

Efficacy of menatetrenone (vitamin K2) against non-vertebral and hip fractures in patients with neurological diseases: meta-analysis of three randomized, controlled trials.

PubMed

Iwamoto, Jun; Matsumoto, Hideo; Takeda, Tsuyoshi

2009-01-01

Patients with neurological diseases such as Alzheimer's disease, stroke and Parkinson's disease have been reported to have vitamin K deficiency secondary to malnutrition, which increases the risk of non-vertebral and hip fractures. The purpose of the present study was to clarify the efficacy of menatetrenone (vitamin K(2)) against non-vertebral and hip fractures in patients with neurological diseases. A literature search was conducted on PubMed from January 1995 to July 2008 to identify randomized controlled trials (RCTs) of use of menatetrenone against non-vertebral and hip fractures in patients with neurological diseases. A meta-analysis of all RCTs meeting these criteria was then performed. Three RCTs of patients with Alzheimer's disease (n = 178, mean age 78 years), stroke (n = 99, mean age 66 years) and Parkinson's disease (n = 110, mean age 72 years) met the criteria for meta-analysis. These RCTs did not include placebo controls but did have non-treatment controls. According to the meta-analysis, the overall relative risks (95% confidence intervals) for non-vertebral and hip fractures with menatetrenone treatment compared with non-treatment were 0.13 (0.05, 0.35) and 0.14 (0.05, 0.43), respectively, in patients with neurological diseases. No severe adverse events were reported with menatetrenone treatment. The present meta-analysis of three RCTs suggests that there is efficacy for menatetrenone treatment against non-vertebral and hip fractures among patients with neurological diseases. Further larger placebo-controlled trials are needed to confirm the results of the present study.

Forefoot Adduction Is a Risk Factor for Jones Fracture.

PubMed

Fleischer, Adam E; Stack, Rebecca; Klein, Erin E; Baker, Jeffrey R; Weil, Lowell; Weil, Lowell Scott

Jones fractures are among the most common fractures of the foot; however, much remains unknown about their etiology. The purpose of the present study was to further examine the risk factors of forefoot and hindfoot alignment on Jones fractures using an epidemiologic study design. We used a retrospective, matched, case-control study design. Cases consisted of patients with acute, isolated Jones fractures confirmed on plain film radiographs seen at our institute from January 2009 to December 2013. Patients presenting with pain unrelated to metatarsal fractures served as controls. Controls were matched to cases by age (±2 years), gender, and year of presentation. Weightbearing foot radiographs were assessed for 13 angular relationships by a single rater. Conditional multivariable logistic regression was used to identify important risk factors. Fifty patients with acute Jones fractures and 200 controls were included. The only significant variables in the final multivariable model were the metatarsus adductus angle (odds ratio [OR] 1.16, 95% confidence interval [CI] 1.08 to 1.25) and fourth/fifth intermetatarsal angle (OR 0.69, 95% CI 0.57 to 0.83)-both measures of static forefoot adduction. The presence of metatarsus adductus (defined as >15°) on foot radiographs was associated with a 2.4 times greater risk of a Jones fracture (adjusted OR 2.4, 95% CI 1.2 to 4.8). We have concluded that the risk of Jones fracture increases with an adducted forefoot posture. In our population, which consisted primarily of patients presenting after a fall (10 of 50; 20%) or misstep/inversion injury (19 of 50; 38%), the hindfoot alignment appeared to be a less important factor. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Clinical comparison between open plating and minimally invasive plate osteosynthesis for displaced proximal humeral fractures: A prospective randomized controlled trial.

PubMed

Sohn, Hoon-Sang; Jeon, Yoon Sang; Lee, JuHan; Shin, Sang-Jin

2017-06-01

Recently, minimally invasive plate osteosynthesis (MIPO) has been widely used for the treatment of proximal humeral fractures. However, there is concern about whether the MIPO in comminuted proximal humeral fractures is also comparable to open plating. The purpose of this study was to compare the clinical and radiographic outcomes of open plating and MIPO for acute displaced proximal humeral fractures. In this prospective, randomized controlled study, 107 patients who had an acute proximal humeral fracture were randomized to either the open plating or MIPO techniques. Forty-five patients treated with open plating and 45 with the MIPO technique who were followed up at least 1year were evaluated. Shoulder functional assessment, operating time, several radiographic parameters, and complications were evaluated at final follow-up. The mean follow-up period was 15.0 months in the open plating and 14.3 months in the MIPO technique. There were no statistically significant differences in functional assessment scores and radiographic parameters between the two groups. High complications rates were found in 4-part fracture in both surgical methods The average operation time in the MIPO group were significantly lower compared to the open plating group (p<0.05). This study showed MIPO in proximal humerus fractures had similar clinical and radiographic outcomes compared to the open plating. However, the MIPO technique in proximal humerus fracture provided significantly shorter operation time than the open plating. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hip fractures: incidence, risk factors, energy absorption, and prevention.

PubMed

Lauritzen, J B

1996-01-01