30 CFR 18.32 - Fastenings-additional requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... preclude improper assembly. (d) Holes for fastenings shall not penetrate to the interior of an explosion...-inch of stock shall be left at the center of the bottom of each hole drilled for fastenings. (f...-tensile strength fastening(s) specified by the applicant. (i) Coil-thread inserts, if used in holes for...

Investigation of threaded fastener structural integrity

NASA Technical Reports Server (NTRS)

1977-01-01

Technical nondestructive evaluation approaches to the determination of fastener integrity were assessed. Existing instruments and methods used to measure stress or strain were examined, with particular interest in fastener shank stress. Industry procedures being followed were evaluated to establish fastener integrity criteria.

HEXPANDO Expanding Head for Fastener-Retention Hexagonal Wrench

NASA Technical Reports Server (NTRS)

Bishop, John

2011-01-01

The HEXPANDO is an expanding-head hexagonal wrench designed to retain fasteners and keep them from being dislodged from the tool. The tool is intended to remove or install socket-head cap screws (SHCSs) in remote, hard-to-reach locations or in circumstances when a dropped fastener could cause damage to delicate or sensitive hardware. It is not intended for application of torque. This tool is made of two assembled portions. The first portion of the tool comprises tubing, or a hollow shaft, at a length that gives the user adequate reach to the intended location. At one end of the tubing is the expanding hexagonal head fitting with six radial slits cut into it (one at each of the points of the hexagonal shape), and a small hole drilled axially through the center and the end opposite the hex is internally and externally threaded. This fitting is threaded into the shaft (via external threads) and staked or bonded so that it will not loosen. At the other end of the tubing is a knurled collar with a through hole into which the tubing is threaded. This knob is secured in place by a stop nut. The second assembled portion of the tool comprises a length of all thread or solid rod that is slightly longer than the steel tubing. One end has a slightly larger knurled collar affixed while the other end is tapered/pointed and threaded. When the two portions are assembled, the all thread/rod portion feeds through the tubing and is threaded into the expanding hex head fitting. The tapered point allows it to be driven into the through hole of the hex fitting. While holding the smaller collar on the shaft, the user turns the larger collar, and as the threads feed into the fitting, the hex head expands and grips the SHCS, thus providing a safe way to install and remove fasteners. The clamping force retaining the SHCS varies depending on how far the tapered end is inserted into the tool head. Initial tests of the prototype tool, designed for a 5 mm or # 10SHCS have resulted in up to 8 lb (.35.6 N) of pull force to dislodge the SHCS from the tool. The tool is designed with a lead-in angle from the diameter of the tubing to a diameter the same as the fastener head, to prevent the fastener head from catching on any obstructions encountered that could dislodge the fastener during retrieval.

Measuring the surface area of fasteners

Treesearch

Douglas R. Rammer; Samuel L. Zelinka

2011-01-01

New product provides a easy way for companies to identify the surface area of threaded and nonthreaded fasteners, especially as changes in wood preservative treatments act to accelerate metal fastener corrosion in wood.

Optical method for measuring the surface area of a threaded fastener

Treesearch

Douglas Rammer; Samuel Zelinka

2010-01-01

This article highlights major aspects of a new optical technique to determine the surface area of a threaded fastener; the theoretical framework has been reported elsewhere. Specifically, this article describes general surface area expressions used in the analysis, details of image acquisition system, and major image processing steps contained within the measurement...

Modified locking thread form for fastener

NASA Technical Reports Server (NTRS)

Roopnarine, (Inventor); Vranish, John D. (Inventor)

1998-01-01

A threaded fastener has a standard part with a standard thread form characterized by thread walls with a standard included angle, and a modified part complementary to the standard part having a modified thread form characterized by thread walls which are symmetrically inclined with a modified included angle that is different from the standard included angle of the standard part's thread walls, such that the threads of one part make pre-loaded edge contact with the thread walls of the other part. The thread form of the modified part can have an included angle that is greater, less, or compound as compared to the included angle of the standard part. The standard part may be a bolt and the modified part a nut, or vice versa. The modified thread form holds securely even under large vibrational forces, it permits bi-directional use of standard mating threads, is impervious to the build up of tolerances and can be manufactured with a wider range of tolerances without loss of functionality, and distributes loading stresses (per thread) in a manner that decreases the possibility of single thread failure.

Quick application/release nut with engagement indicator (commercial application of an innovative nut design)

NASA Technical Reports Server (NTRS)

Wright, Jay M.

1991-01-01

This is an assembly which permits a fastener to be inserted or removed from either side with an indicator of fastener engagement. The nut has a plurality of segments, preferably at least three segments, which are internally threaded, spring loaded apart by an internal spring, and has detents on opposite sides which force the nut segments into operative engagement with a threaded member when pushed in and release the segments for quick insertion or removal of the fastener when moved out. When the nut is installed, end pressure on the detents presses the nut segments into operative engagement with a threaded member where continued rotation locks the structure together with the detents depressed to indicate positive locking engagement of the nut. On removal, counterclockwise rotation relieves the endwise pressure on the detents, permitting internal springs to force the detents outward, allowing the nut segments to move outward and separate to permit quick removal of the fastener.

Aerospace Threaded Fastener Strength in Combined Shear and Tension Loading

NASA Technical Reports Server (NTRS)

Steeve, B. E.; Wingate, R. J.

2012-01-01

A test program was initiated by Marshall Space Flight Center and sponsored by the NASA Engineering and Safety Center to characterize the failure behavior of a typical high-strength aerospace threaded fastener under a range of shear to tension loading ratios for both a nut and an insert configuration where the shear plane passes through the body and threads, respectively. The testing was performed with a customized test fixture designed to test a bolt with a single shear plane at a discrete range of loading angles. The results provide data to compare against existing combined loading failure criteria and to quantify the bolt strength when the shear plane passes through the threads.

Evaluation of MSFC-STD-486, ''Threaded Fasteners, Torque Limits For'' for use in the construction of aerospace vhicles

NASA Technical Reports Server (NTRS)

Hart, J. F.

1973-01-01

MSFC-STD-486, Threaded Fasteners, Torque Limits For, is a relatively new standard that has not had much user experience. This test was run to provide such experience and verify the values in MSFC-STD-486. This was accomplished by plotting torque-tension curves on aluminum and alloy steel aircraft quality bolts and nuts through 1/2 inch in diameter.

Fastener Design Manual

NASA Technical Reports Server (NTRS)

Barrett, Richard T.

1990-01-01

This manual was written for design engineers to enable them to choose appropriate fasteners for their designs. Subject matter includes fastener material selection, platings, lubricants, corrosion, locking methods, washers, inserts, thread types and classes, fatigue loading, and fastener torque. A section on design criteria covers the derivation of torque formulas, loads on a fastener group, combining simultaneous shear and tension loads, pullout load for tapped holes, grip length, head styles, and fastener strengths. The second half of this manual presents general guidelines and selection criteria for rivets and lockbolts.

Process Specification for Eddy Current Inspection

NASA Technical Reports Server (NTRS)

Koshti, Ajay

2011-01-01

This process specification establishes the minimum requirements for eddy current inspection of flat surfaces, fastener holes, threaded fasteners and seamless and welded tubular products made from nonmagnetic alloys such as aluminum and stainless steel.

Connector systems for structures

NASA Technical Reports Server (NTRS)

Lupo, Christian (Inventor); Evenson, Erik (Inventor); Wesselski, Clarence (Inventor)

1993-01-01

A releasable coupling device for connecting two members to one another where a collet type fastener has normally retracted latching fingers insertable into a latching recess and a longitudinally movable expander for activating the fastener is described. The longitudinal movement is retained with a paraffin actuated system which can reset. The longitudinal movement of the expander in one direction is through a one way threaded ratchet system which provides an automatic locking action and the expander is movable in either direction by an independently operated threaded action.

Quick application/release nut with engagement indicator

NASA Technical Reports Server (NTRS)

Wright, Jay M. (Inventor)

1992-01-01

A composite nut is shown which permits a fastener to be inserted or removed from either side with an indicator of fastener engagement. The nut has a plurality of segments, preferably at least three segments, which are internally threaded, spring loaded apart by an internal spring, and has detents on opposite sides which force the nut segments into operative engagements with a threaded member when pushed in and release the segments for quick insertion or removal of the nut when moved out. When the nut is installed, end pressure on one of the detents presses the nut segments into operative engagement with a threaded member where continued rotation locks the structure together with the detents depressed to indicate positive locking engagement of the nut. On removal, counterclockwise rotation of the nut relieves the endwise pressure on the detents, permitting internal springs to force the detents outward and allowing the nut segments to move outward and separate to permit quick removal of the fastener.

Bolt and nut evaluator

NASA Technical Reports Server (NTRS)

Kerley, James J. (Inventor); Burkhardt, Raymond (Inventor); White, Steven (Inventor)

1994-01-01

A device for testing fasteners such as nuts and bolts is described which consists of a fixed base plate having a number of threaded and unthreaded holes of varying size for receiving the fasteners to be tested, a torque marking paper taped on top the fixed base plate for marking torque-angle indicia, a torque wrench for applying torque to the fasteners being tested, and an indicator for showing the torque applied to the fastener. These elements provide a low cost, nondestructive device for verifying the strength of bolts and nuts.

Fastener apparatus

NASA Technical Reports Server (NTRS)

While, Donald M. (Inventor); Matza, Edward C. (Inventor)

1987-01-01

A fastening apparatus is adapted to be inserted and removed from one side of a work piece having an opposite side which is substantially inaccessible to a worker. A first, externally threaded member is threadingly engaged with a receiving structure, and a second member is inserted within corresponding seats or grooves for interlocking the two members. In the preferred embodiment diverting seats are provided for forming the second member into locking engagement between the receiving structure and the first member. In one embodiment, seat structures are provided for engaging frangible panels or the like for high temperature applications.

Tool For Driving Many Fasteners Simultaneously

NASA Technical Reports Server (NTRS)

Cook, Joseph S., Jr.

1995-01-01

Proposed tool tightens or loosens several bolts, screws, nuts, or other threaded fasteners arranged in circle on compressor head, automotive wheel, pipe-end flange, or similar object. Enables assembly or disassembly in fraction of time needed to tighten fasteners one at a time. Simultaneously applies same torque to all fasteners, preventing distortion and enhancing reliability. Concept not limited to circular fastener patterns. Adapted to rectangular configurations like on engine intake manifolds, by adding gears to drive train to provide proper spacing. Designed to deliver fixed or adjustable maximum torque. To ensure even seal loading, piston pressure simultaneously ramped from initial to final values to maintain relatively constant torque loading on all fasteners until final specifications limit achieved.

Push Type Fastener

NASA Technical Reports Server (NTRS)

Jackson, Steven A. (Inventor)

1996-01-01

A push type fastener for fastening a movable structural part to a fixed structural part, wherein the coupling and decoupling actions are both a push type operation, the fastener consisting of a plunger having a shank with a plunger head at one end and a threaded end portion at the other end, an expandable grommet adapted to receive the plunger shank there through, and an attachable head which is securable to the threaded end of the plunger shank. The fastener requires each structural part to be provided with an aperture and the attachable head to be smaller than the aperture in the second structural part. The plunger is extensible through the grommet and is structurally configured with an external camming surface which is cooperatively engageable with internal surfaces of the grommet so that when the plunger is inserted in the grommet, the relative positioning of said cooperable camming surfaces determines the expansion of the grommet. Coupling of the parts is effected when the grommet is inserted in the aperture in the fixed structural part and expanded by pushing the plunger head and plunger at least a minimal distance through the grommet. Decoupling is effected by pushing the attachable head.

Prevailing Torque Locking Feature in Threaded Fasteners Using Anaerobic Adhesive

NASA Technical Reports Server (NTRS)

Hernandez, Alan; Hess, Daniel P.

2016-01-01

This paper presents results from tests to assess the use of anaerobic adhesive for providing a prevailing torque locking feature in threaded fasteners. Test procedures are developed and tests are performed on three fastener materials, four anaerobic adhesives, and both unseated assembly conditions. Five to ten samples are tested for each combination. Tests for initial use, reuse without additional adhesive, and reuse with additional adhesive are performed for all samples. A 48-hour cure time was used for all initial use and reuse tests. Test data are presented as removal torque versus removal angle with the specification required prevailing torque range added for performance assessment. Percent specification pass rates for the all combinations of fastener material, adhesive, and assembly condition are tabulated and reveal use of anaerobic adhesive as a prevailing torque locking feature is viable. Although not every possible fastener material and anaerobic adhesive combination provides prevailing torque values within specification, any combination can be assessed using the test procedures presented. Reuse without additional anaerobic adhesive generally provides some prevailing torque, and in some cases within specification. Reuse with additional adhesive often provides comparable removal torque data as in initial use.

Thermal Preload Relaxation of Bolted CFRP Structures for Flexible Life Time Design Methodology

NASA Astrophysics Data System (ADS)

Hubbertz, Hendrik; Friedrich, Christoph

2014-06-01

Taking into account the assembly, maintenance and repair of component systems, it becomes clear that mechanical fastening is necessary also for CFRP structures besides adhesive bonding. Threaded fasteners usually prestress CFRP materials perpendicular to the fibres. In this direction the high strength-increase by the carbon fibres is subordinated and the material properties are dominated by the relatively low strength plastic matrix. The following chapters explain the basics of preload loss at threaded fasteners and show the results of experiments with different influences on preload relaxation with CFRP materials. As the presented studies were carried out under the influence of temperature, thermal load plastification will be regarded as priority. The structural changes in the material are also documented with microscope images as well as an outlook for further research is given.

Reversible Nut With Engagement Indication

NASA Technical Reports Server (NTRS)

Wright, Jay M.

1995-01-01

Document describes nut allowing fastener inserted or removed from either side by simply sliding fastener in or out. Detents on each face of nut, when pushed in, ensure positive engagement of threads. Followed by conventional clockwise turning to lock and counterclockwise turning to unlock nut. Detents, when viewed, show whether nut in positive lock.

Research of thread rolling on difficult-to-cut material workpieces

NASA Astrophysics Data System (ADS)

Popov, A. Yu; Bugay, I. A.; Nazarov, P. V.; Evdokimova, O. P.; Popov, P. E.; Vasilyev, E. V.

2018-01-01

In medicine production Ti-6Al-4V Grade 5 alloys are used. One of the most important tasks is to increase the strength of the products and decrease in value. The possibility to roll special thread on Ti-6Al-4V Grade 5 alloy workpiece on 2-roller thread rolling machine has been studied. This is wrought alloy, treatment of which in cold condition causes difficulties due to low plasticity. To obtain Ti-6Al-4V Grade 5 alloy product with thread by rolling is rather difficult. This is due to large axial workpiece displacements resulting from large alloy resistance to cold plastic deformation. The provision of adequate kinematics requires experimental researches and the selection of modes - speed of rolling and pressure on the movable roller. The purpose of the work is to determine the optimal modes for rolling thread on titanium alloy workpiece. It has been stated that, after rolling, the product strength has increased up to 30%. As a result of the work, the unit has been made and recommendations to choose the optimal rolling process modes have been offered.

Lubricating Holes for Corroded Nuts and Bolts

NASA Technical Reports Server (NTRS)

Penn, B. G.; Clemons, J. M.; Ledbetter, Frank E., III

1986-01-01

Corroded fasteners taken apart more easily. Lubricating holes bored to thread from three of flats. Holes facilitate application of penetrating oil to help loosen nut when rusted onto bolt. Holes make it possible to apply lubricants and rust removers directly to more of thread than otherwise reachable.

30 CFR 7.304 - Technical requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (coarse, loose fitting) threads. The covers shall be secured against loosening. (5) Flat surfaces between... flame-arresting path shall be finished during the manufacturing process to not more than 250 microinches... requirements as the pole piece. (12) Coil-thread inserts, if used in holes for fastenings, shall meet the...

30 CFR 7.304 - Technical requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (coarse, loose fitting) threads. The covers shall be secured against loosening. (5) Flat surfaces between... flame-arresting path shall be finished during the manufacturing process to not more than 250 microinches... requirements as the pole piece. (12) Coil-thread inserts, if used in holes for fastenings, shall meet the...

30 CFR 7.304 - Technical requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (coarse, loose fitting) threads. The covers shall be secured against loosening. (5) Flat surfaces between... flame-arresting path shall be finished during the manufacturing process to not more than 250 microinches... requirements as the pole piece. (12) Coil-thread inserts, if used in holes for fastenings, shall meet the...

30 CFR 7.304 - Technical requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (coarse, loose fitting) threads. The covers shall be secured against loosening. (5) Flat surfaces between... flame-arresting path shall be finished during the manufacturing process to not more than 250 microinches... requirements as the pole piece. (12) Coil-thread inserts, if used in holes for fastenings, shall meet the...

30 CFR 7.304 - Technical requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (coarse, loose fitting) threads. The covers shall be secured against loosening. (5) Flat surfaces between... flame-arresting path shall be finished during the manufacturing process to not more than 250 microinches... requirements as the pole piece. (12) Coil-thread inserts, if used in holes for fastenings, shall meet the...

Push type fastener

NASA Technical Reports Server (NTRS)

Jackson, Steven A. (Inventor)

1994-01-01

A push type fastener for fastening a movable structural part (41) to a fixed structural part (43), wherein the coupling and decoupling actions are both a push type operation, the fastener consisting of a plunger (12) having a shank (20) with a plunger head (18) at one end and a threaded end portion (26a) at the other end, an expandable grommet (14) adapted to receive the plunger shank (20) therethrough, and an attachable head (16) which is securable to the threaded end of the plunger shank (20). The fastener (10) requires each structural part (41, 43) to be provided with an aperture (45, 46) and the attachable head (16) to be smaller than the aperture (46) in the second structural part. The plunger (12) is extensible through the grommet (14) and is structurally configured with an external camming surface (25) which is cooperatively engageable with internal surfaces (38) of the grommet so that when the plunger is inserted in the grommet, the relative positioning of said cooperable camming surfaces determines the expansion of the grommet. Coupling of the parts is effected when the grommet is inserted in the aperture (46) in the fixed structural part (43) and expanded by pushing the plunger head (18) and plunger at least a minimal distance through the grommet. Decoupling is effected by pushing the attachable head (16).

Tamper indicating bolt

DOEpatents

Blagin, Sergei V.; Barkanov, Boris P.

2004-09-14

A tamper-indicating fastener has a cylindrical body with threads extending from one end along a portion of the body, and a tamper indicating having a transducer for converting physical properties of the body into electronic data; electronics for recording the electronic data; and means for communicating the recorded information to a remote location from said fastener. The electronics includes a capacitor that varies as a function of force applied by the fastener, and non-volatile memory for recording instances when the capacitance varies, providing an indication of unauthorized access.

16 CFR 1616.4 - Sampling and acceptance procedures.

Code of Federal Regulations, 2014 CFR

2014-01-01

... a suitable thread and stitch. The specimen shall include each of the components over its entire... fabric in Tightened Sampling must be discontinued until that part of the process or component which is... otherwise attaching the trim shall be done with thread or fastening material of the same composition and...

Locking Nut and Bolt

NASA Technical Reports Server (NTRS)

Bishop, R.

1983-01-01

Threaded fastener locks parts securely together despite together large loosening torques, even under conditions of high temperature and vibration. Positive locking action is suitable for use where conventional fasteners tend to work loose--for example, on high-speed rotating machinery. Bolt, nut and key are joined together so key occupies alined slots in bolt and nut and prevents nut from rotating off bolt.

Fastener stretcher

NASA Technical Reports Server (NTRS)

Oconnor, J. W.; Orem, V. C. (Inventor)

1973-01-01

A description is given of a fastener stretcher used to apply a substantial pure axial tensile force to a structural bolt or similar fastening element. The system is comprised of a pair of telescoping elements, one of which is temporarily secured to the bolt. By spreading the telescoping elements axially, the bolt is tensioned axially to permit a nut or the like to be threaded with a minimum of torque; when the elements are then removed from the bolt, the axial forces on the bolt are taken up by the nut to retain the bolt in its stressed state.

Forces associated with pneumatic power screwdriver operation: statics and dynamics.

PubMed

Lin, Jia-Hua; Radwin, Robert G; Fronczak, Frank J; Richard, Terry G

2003-10-10

The statics and dynamics of pneumatic power screwdriver operation were investigated in the context of predicting forces acting against the human operator. A static force model is described in the paper, based on tool geometry, mass, orientation in space, feed force, torque build up, and stall torque. Three common power hand tool shapes are considered, including pistol grip, right angle, and in-line. The static model estimates handle force needed to support a power nutrunner when it acts against the tightened fastener with a constant torque. A system of equations for static force and moment equilibrium conditions are established, and the resultant handle force (resolved in orthogonal directions) is calculated in matrix form. A dynamic model is formulated to describe pneumatic motor torque build-up characteristics dependent on threaded fastener joint hardness. Six pneumatic tools were tested to validate the deterministic model. The average torque prediction error was 6.6% (SD = 5.4%) and the average handle force prediction error was 6.7% (SD = 6.4%) for a medium-soft threaded fastener joint. The average torque prediction error was 5.2% (SD = 5.3%) and the average handle force prediction error was 3.6% (SD = 3.2%) for a hard threaded fastener joint. Use of these equations for estimating handle forces based on passive mechanical elements representing the human operator is also described. These models together should be useful for considering tool handle force in the selection and design of power screwdrivers, particularly for minimizing handle forces in the prevention of injuries and work related musculoskeletal disorders.

Displaceable Spur Gear Torque Controlled Driver and Method

NASA Technical Reports Server (NTRS)

Cook, Joseph S., Jr. (Inventor)

1996-01-01

Methods and apparatus are provided for a torque driver including a laterally displaceable gear support member to carry an output spur gear. A biasing assembly biases the output spur gear into engagement with a pinion to which is applied an input torque greater than a desired output torque limit for a threaded fastener such as a nut or screw. A coiled output linkage connects the output spur gear with a fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. A gauged selector mechanism is provided to laterally displace multiple driven members for fasteners arranged in differing configurations. The torque limit is selectably adjustable and may be different for fasteners within the same fastener configuration.

Displaceable spur gear torque controlled driver and method

NASA Technical Reports Server (NTRS)

Cook, Joseph S., Jr. (Inventor)

1994-01-01

Methods and apparatus are provided for a torque driver including a laterally displaceable gear support member to carry an output spur gear. A biasing assembly biases the output spur gear into engagement with a pinion to which is applied an input torque greater than a desired output torque limit for a threaded fastener such as a nut or screw. A coiled output linkage connects the output spur gear with a fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. A gauged selector mechanism is provided to laterally displace multiple driver members for fasteners arranged in differing configurations. The torque limit is selectably adjustable and may be different for fasteners within the same fastener configuration.

Preload Loss in a Spacecraft Fastener via Vibration-Induced Unwinding

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher; Howard, S. Adam; Hess, Daniel P.

2018-01-01

Sound engineering practice requires that fasteners and bolted joints maintain preload in service. NASA recently concluded a series of vibration tests of a multicomponent structure intended to simulate an upper stage section of a launch vehicle. The stacked components were joined through six circumferentially placed bolted cup-cone-style pyrotechnic joint mechanisms designed to share spacecraft structural loads and then enable separation during ascent. Over the course of the vibration test campaign, all six bolted cup-cone mechanisms experienced some degree of preload loss with two mechanisms losing half of their original bolt preload. A subsequent forensic anomaly investigation concluded that vibration-induced unwinding of the preload nut-and-bolt assemblies occurred despite the use of safety wire and high levels of thread friction. A series of experiments were done to better understand how large, heavily preloaded fasteners could unwind. Additionally, thread friction torque was measured and the fastener locking capability of safety wire was evaluated. The friction coefficient between the clamped cup-cone components was characterized and finally a highly instrumented mechanism-level vibration test was done to reproduce the unwinding phenomenon to better understand the mechanism's behavior. The conclusion drawn was that vibration and structural forces led to relative motion (sliding) of the clamped components, resulting in self-loosening and unwinding effects on the nut-and-bolt assembly. To counter this phenomenon, more effective fastener locking methodologies were recommended and a follow-on effort was initiated to quantify the relationship between preload, component motion, and resulting unwinding forces. It is hoped that elucidation of these effects can be used to design more effective fastener locking features.

Solid Rocket Booster Hydraulic Pump Port Cap Joint Load Testing

NASA Technical Reports Server (NTRS)

Gamwell, W. R.; Murphy, N. C.

2004-01-01

The solid rocket booster uses hydraulic pumps fabricated from cast C355 aluminum alloy, with 17-4 PH stainless steel pump port caps. Corrosion-resistant steel, MS51830 CA204L self-locking screw thread inserts are installed into C355 pump housings, with A286 stainless steel fasteners installed into the insert to secure the pump port cap to the housing. In the past, pump port cap fasteners were installed to a torque of 33 Nm (300 in-lb). However, the structural analyses used a significantly higher nut factor than indicated during tests conducted by Boeing Space Systems. When the torque values were reassessed using Boeing's nut factor, the fastener preload had a factor of safety of less than 1, with potential for overloading the joint. This paper describes how behavior was determined for a preloaded joint with a steel bolt threaded into steel inserts in aluminum parts. Finite element models were compared with test results. For all initial bolt preloads, bolt loads increased as external applied loads increased. For higher initial bolt preloads, less load was transferred into the bolt, due to external applied loading. Lower torque limits were established for pump port cap fasteners and additional limits were placed on insert axial deformation under operating conditions after seating the insert with an initial preload.

Ultrasonic extensometer measures bolt preload

NASA Technical Reports Server (NTRS)

Daniels, C. M., Jr.

1978-01-01

Extensometer using ultrasonic pulse reflections to measure elongations in tightened belts and studs is much more accurate than conventional torque wrenches in application of specified preload to bolts and other threaded fasteners.

Experimental Research on the Elastic Deformation Mode of S235JR Rolled Steel Fastened between the Centers of a Universal Lathe

NASA Astrophysics Data System (ADS)

Tabacaru, LL; Axinte, E.; Musca, G.

2016-11-01

Elastic deformations of the technological system occur during the mechanical treatment of a blank, regardless of the manner in which it is fastened. The elastic deformation of the blank is significant especially when machining shaft-like parts. The purpose of our research is to compare the mathematical model of blank deformation to the experimental model when the blank, which is a part belonging to the shaft class, is fastened between centers.

Nondestructive ultrasonic measurement of bolt preload using the pulsed-phase locked-loop interferometer

NASA Technical Reports Server (NTRS)

Allison, S. G.; Heyman, J. S.

1985-01-01

Achieving accurate preload in threaded fasteners is an important and often critical problem which is encountered in nearly all sectors of government and industry. Conventional tensioning methods which rely on torque carry with them the disadvantage of requiring constant friction in the fastener in order to accurately correlate torque to preload. Since most of the applied torque typically overcomes friction rather than tensioning the fastener, small variations in friction can cause large variations in preload. An instrument called a pulsed phase locked loop interferometer, which was recently developed at NASA Langley, has found widespread use for measurement of stress as well as material properties. When used to measure bolt preload, this system detects changes in the fastener length and sound velocity which are independent of friction. The system is therefore capable of accurately establishing the correct change in bolt tension. This high resolution instrument has been used for precision measurement of preload in critical fasteners for numerous applications such as the space shuttle landing gear and helicopter main rotors.

Metal-to-ceramic attachment device

DOEpatents

Pavelka, Edwin A.; Grindstaff, Quirinus G.; Scheppele, Stuart E.

1985-01-01

A metal-to-ceramic fastening device is disclosed for securing a metal member to a ceramic member with respective confronting surfaces thereon clamped together, comprising a threaded bolt adapted to extend through a bolt hole in the metal member and into an aligned opening in the ceramic member, a rod nut threadedly receiving the bolt and adapted to span the opening in the ceramic member, and a pressure limiting member received on the bolt between the nut and the confronting surface of the metal member for limiting the movement of the nut toward the metal member when the bolt is tightened, so as to limit the pressure applied by the nut to the ceramic member to avoid damage thereto. The fastening device also prevents damage to the ceramic member due to thermal stresses. The pressure limiting member may have a shallow dish-shaped depression facing the rod nut to assist in accommodating thermal stresses.

Effect of thread shape on screw stress concentration by photoelastic measurements

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

Dragoni, E.

1994-11-01

The screw stress concentration for six nut-bolt connections embodying three different thread profiles and two nut shapes is measured photoelastically. Buttress (nearly zero flank angle), trapezoidal (15-deg flank angle), and triangular (30-deg flank angle) thread forms are examined in combination with standard and lip-type nuts. The effect of the thread profile on the screw stress concentration appears to be dependent upon the kind of nut considered. If the fastening incorporates a standard nut, the buttress thread is stronger than the triangular one, which, in turn, behaves better than the trapezoidal contour. The improvement is roughly a 20% reduction in themore » stress concentration factor from the trapezoidal to the buttress thread. In the case of lip nut, conversely, this tendency is somewhat reversed, with the trapezoidal thread performing slightly (but not decidedly) better than the other two shapes. Finally, averaged over all three thread forms, the lip nut exhibits a stress concentration factor which is about 50% lower than that of the standard nut.« less

Methodology for Determining Limit Torques for Threaded Fasteners

NASA Technical Reports Server (NTRS)

Hissam, Andy

2011-01-01

In aerospace design, where minimizing weight is always a priority, achieving the full capacity from fasteners is essential. To do so, the initial bolt preload must be maximized. The benefits of high preload are well documented and include improved fatigue resistance, a stiffer joint, and resistance to loosening. But many factors like elastic interactions and embedment tend to lower the initial preload placed on the bolt. These factors provide additional motivation to maximize the initial preload. But, to maximize bolt preload, you must determine what torque to apply. Determining this torque is greatly complicated by the large preload scatter generally seen with torque control. This paper presents a detailed methodology for generating limit torques for threaded fasteners. This methodology accounts for the large scatter in preload found with torque control, and therefore, addresses the statistical nature of the problem. It also addresses prevailing torque, a feature common in aerospace fasteners. Although prevailing torque provides a desired locking feature, it can also increase preload scatter. In addition, it can limit the amount of preload that can be generated due to the torsion it creates in the bolt. This paper discusses the complications of prevailing torque and how best to handle it. A wide range of torque-tension bolt testing was conducted in support of this research. The results from this research will benefit the design engineer as well as analyst involved in the design of bolted joints, leading to better, more optimized structural designs.

Threaded Fastener Positive Anti-Rotation Locking Device

NASA Technical Reports Server (NTRS)

Hartman, Timm E. (Inventor); Hanlon, Casey (Inventor); Laidlaw, Mitchell (Inventor); Geck, Kellan (Inventor)

2015-01-01

An apparatus includes a shaft, a device, a fastener, and an anti-rotation clip. The shaft is configured for rotation. The device is mounted on, and surrounds at least a portion of, the shaft, and has first and second protrusions that are formed on one side and are spaced apart to define a tab space. The fastener is rotationally mounted relative to the shaft, and includes a tab slot formed in its outer surface that extends radially inwardly and is disposed radially inwardly of the tab space. The anti-rotation clip includes a main body portion and a head portion that has a first tab portion and a second tab portion. At least a portion the main body portion is disposed between the device and the fastener, the first tab is disposed in the tab space, and the second tab is disposed in the tab slot.

Tires

DTIC Science & Technology

2015-12-15

during shipment, protect the threads of the valve stem, and shield the folded tube against abrasion by the threads . A metal valve cap contains a...Test types include force and moment, rolling resistance , steer frequency response, load-deflection curves, characteristics, endurance, and...several on-vehicle tests. 15. SUBJECT TERMS tire test rig force and moment rolling resistance steer frequency response

LDEF mechanical systems

NASA Technical Reports Server (NTRS)

Spear, W. Steve; Dursch, Harry W.

1992-01-01

Following LDEF retrieval, a number of studies were made of mechanical hardware and structure flown on the LDEF. The primary objectives are to determine the effects of long term space exposure on (1) mechanisms either used on LDEF or as part of individual experiments; (2) LDEF structural components; and (3) fasteners. Results from examination and testing of LDEF structure, fasteners, LDEF end support beam, environment exposure control canisters, experiment tray clamps, LDEF grapple fixtures, and viscous damper are presented. The most significant finding is the absence of space exposure related cold welding. The instances of seizure or removal difficulties initially attributed to cold welding were shown to have resulted from installation galling damage or improper removal techniques. Widespread difficulties encountered with removal of stainless steel fasteners underscore the need for effective thread lubrication schemes to ensure successful application of proposed orbital replacement units onboard Space Station Freedom.

Method and apparatus for spraying molten materials

DOEpatents

Glovan, R.J.; Tierney, J.C.; McLean, L.L.; Johnson, L.L.; Nelson, G.L.; Lee, Y.M.

1996-06-25

A metal spray apparatus is provided with a supersonic nozzle. Molten metal is injected into a gas stream flowing through the nozzle under pressure. By varying the pressure of the injected metal, the droplet can be made in various selected sizes with each selected size having a high degree of size uniformity. A unique one piece graphite heater provides easily controlled uniformity of temperature in the nozzle and an attached tundish which holds the pressurized molten metal. A unique U-shaped gas heater provides extremely hot inlet gas temperatures to the nozzle. A particularly useful application of the spray apparatus is coating of threads of a fastener with a shape memory alloy. This permits a fastener to be easily inserted and removed but provides for a secure locking of the fastener in high temperature environments. 12 figs.

Functional Drafting, Drafting--Intermediate: 9255.02.

ERIC Educational Resources Information Center

Dade County Public Schools, Miami, FL.

The course consists of six instructional blocks totaling 135 clock hours: (1) functional drafting, (2) threads and fasteners, (3) pictorial drawings, (4) introduction to electronic drafting, (5) introduction to piping drafting, and (6) Quinmester posttest. Mastery of skills indicated in Drafting-Basic--9255.01 is a prerequisite. In the functional…

30 CFR 7.98 - Technical requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... the manufacturing process to not more than 250 microinches. (ii) A means shall be provided to ensure...) The minimum thread engagement of fastenings shall be equal to or greater than the nominal diameter of... flame-arresting path shall be finished during the manufacturing process to not more than 250 microinches...

30 CFR 7.98 - Technical requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... the manufacturing process to not more than 250 microinches. (ii) A means shall be provided to ensure...) The minimum thread engagement of fastenings shall be equal to or greater than the nominal diameter of... flame-arresting path shall be finished during the manufacturing process to not more than 250 microinches...

30 CFR 7.98 - Technical requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the manufacturing process to not more than 250 microinches. (ii) A means shall be provided to ensure...) The minimum thread engagement of fastenings shall be equal to or greater than the nominal diameter of... flame-arresting path shall be finished during the manufacturing process to not more than 250 microinches...

Protective interior wall and attaching means for a fusion reactor vacuum vessel

DOEpatents

Phelps, R.D.; Upham, G.A.; Anderson, P.M.

1985-03-01

The wall basically consists of an array of small rectangular plates attached to the existing walls with threaded fasteners. The protective wall effectively conceals and protects all mounting hardware beneath the plate array, while providing a substantial surface area that will absorb plasma energy.

Power hand tool kinetics associated with upper limb injuries in an automobile assembly plant.

PubMed

Ku, Chia-Hua; Radwin, Robert G; Karsh, Ben-Tzion

2007-06-01

This study investigated the relationship between pneumatic nutrunner handle reactions, workstation characteristics, and prevalence of upper limb injuries in an automobile assembly plant. Tool properties (geometry, inertial properties, and motor characteristics), fastener properties, orientation relative to the fastener, and the position of the tool operator (horizontal and vertical distances) were measured for 69 workstations using 15 different pneumatic nutrunners. Handle reaction response was predicted using a deterministic mechanical model of the human operator and tool that was previously developed in our laboratory, specific to the measured tool, workstation, and job factors. Handle force was a function of target torque, tool geometry and inertial properties, motor speed, work orientation, and joint hardness. The study found that tool target torque was not well correlated with predicted handle reaction force (r=0.495) or displacement (r=0.285). The individual tool, tool shape, and threaded fastener joint hardness all affected predicted forces and displacements (p<0.05). The average peak handle force and displacement for right-angle tools were twice as great as pistol grip tools. Soft-threaded fastener joints had the greatest average handle forces and displacements. Upper limb injury cases were identified using plant OSHA 200 log and personnel records. Predicted handle forces for jobs where injuries were reported were significantly greater than those jobs free of injuries (p<0.05), whereas target torque and predicted handle displacement did not show statistically significant differences. The study concluded that quantification of handle reaction force, rather than target torque alone, is necessary for identifying stressful power hand tool operations and for controlling exposure to forces in manufacturing jobs involving power nutrunners. Therefore, a combination of tool, work station, and task requirements should be considered.

Quick-connect fasteners for assembling devices in space

NASA Technical Reports Server (NTRS)

Evenson, Erik E. (Inventor); Wesselski, Clarence J. (Inventor); Ruiz, Steve C. (Inventor)

1993-01-01

A quick-connect fastener of a relatively-simple straightforward design is arranged with a tubular body adapted to be engaged against an attachment fitting in coincidental alignment with an opening in that fitting. A tubular collet having flexible fingers projecting from its forward end is arranged in the fastener body to be shifted forwardly by an elongated expander member coaxially arranged within the tubular collet for advancing the collet fingers into the opening in the attachment fitting. Biasing means are arranged between the elongated expander member and a rotatable actuator which is threadedly mounted within the tubular collet so as to be rotated for urging the expander member into engagement with the collet fingers. A first coupling member is arranged on the rotatable actuator to be accessible from outside of the fastener so that a second coupling member on the distal end of a flexible shaft can be introduced into the fastener body and coupled to the first coupling member to enable a typical actuating tool coupled to the shaft outside of the fastener body to be operated for advancing the outwardly-enlarged ends of the collet fingers into the opening in the attachment fitting and thereafter rotating the actuator member to expand the fingers within the opening for releasably latching the fastener to that attachment fitting. Upon expansion of the collet fingers, the biasing means impose a biasing force on the expander to releasably retain the fingers in their latching positions.

Promising Sparingly Alloyed Boron-Bearing Steels for the Production of High-Strength Fasteners

NASA Astrophysics Data System (ADS)

Bobylev, M. V.; Koroleva, E. G.; Shtannikov, P. A.

2005-05-01

The main advantages of boron-bearing steels used for production of rolled sections at cold upset shops of Russian automotive plants are considered. A thermodynamic model for the majority of boron-bearing steels for high-strength fasteners is used to plot nomograms characterizing the effect of titanium, aluminum, nitrogen, and boron on the amount of nitrides and oxides segregated in crystallization and on the content of effective boron. The effect of effective boron on the characteristics of hardenability is estimated. The studies conducted are used for determining the range of permissible contents of titanium and aluminum ensuring through hardenability of rolled bars from steels 12G1R, 20G2R, and 30G1R up to 25 mm in diameter.

Metal spray apparatus with a U-shaped electric inlet gas heater and a one-piece electric heater surrounding a nozzle

DOEpatents

Glovan, Ronald J.; Tierney, John C.; McLean, Leroy L.; Johnson, Lawrence L.; Verbael, David J.

1995-01-01

An electrically heated metal spray apparatus is provided with a supersonic nozzle. Molten metal is injected into a gas stream flowing through the nozzle under pressure. By varying the pressure of the injected metal, the droplet can be made in various selected sizes with each selected size having a high degree of size uniformity. A unique one piece graphite heater provides easily controlled uniformity of temperature in the nozzle and an attached tundish which holds the pressurized molten metal. A unique U-shaped gas heater provides extremely hot inlet gas temperatures to the nozzle. A particularly useful application of the spray apparatus is coating of threads of a fastener with a shape memory alloy. This permits a fastener to be easily inserted and removed but provides for a secure locking of the fastener in high temperature environments.

Installation Torque Tables for Noncritical Applications

NASA Technical Reports Server (NTRS)

Rivera-Rosario, Hazel T.; Powell, Joseph S.

2017-01-01

The objective of this project is to define torque values for bolts and screws when loading is not a concern. Fasteners require a certain torque to fulfill its function and prevent failure. NASA Glenn Research Center did not have a set of fastener torque tables for non-critical applications without loads, usually referring to hand-tight or wrench-tight torqueing. The project is based on two formulas, torque and pullout load. Torque values are calculated giving way to preliminary data tables. Testing is done to various bolts and metal plates, torqueing them until the point of failure. Around 640 torque tables were developed for UNC, UNF, and M fasteners. Different lengths of thread engagement were analyzed for the 5 most common materials used at GRC. The tables were put together in an Excel spreadsheet and then formatted into a Word document. The plan is to later convert this to an official technical publication or memorandum.

Metal spray apparatus with a U-shaped electric inlet gas heater and a one-piece electric heater surrounding a nozzle

DOEpatents

Glovan, R.J.; Tierney, J.C.; McLean, L.L.; Johnson, L.L.; Verbael, D.J.

1995-10-17

An electrically heated metal spray apparatus is provided with a supersonic nozzle. Molten metal is injected into a gas stream flowing through the nozzle under pressure. By varying the pressure of the injected metal, the droplet can be made in various selected sizes with each selected size having a high degree of size uniformity. A unique one piece graphite heater provides easily controlled uniformity of temperature in the nozzle and an attached tundish which holds the pressurized molten metal. A unique U-shaped gas heater provides extremely hot inlet gas temperatures to the nozzle. A particularly useful application of the spray apparatus is coating of threads of a fastener with a shape memory alloy. This permits a fastener to be easily inserted and removed but provides for a secure locking of the fastener in high temperature environments. 12 figs.

Metrics for Mechanics and Other Practical People.

ERIC Educational Resources Information Center

Richmond, Doug

This handbook on the metric system is printed in a large type for ease of reading. It includes several tables of often-used facts. A brief background of the metric system is presented, followed by chapters on metric uses with electricity, length, pressure, temperature, threaded fastenings, tools, torque, volume, and weight. Each chapter provides a…

78 FR 21101 - Certain Steel Threaded Rod From the People's Republic of China: Preliminary Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-09

.... Ltd. PSGT Trading Jingjiang Ltd. Qingdao Free Trade Zone Health Intl. Shanghai East Best Foreign Trade...) Shanghai Furen International Trading; and (5) Shanghai Printing and Packaging Machinery Corp. No other... International Trading Co. Ningbo Qunli Fastener Manufacture Co., Ltd. Ningbo Shuanglin Auto Parts Co., Ltd...

78 FR 66330 - Certain Steel Threaded Rod From the People's Republic of China; Final Results of Third...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-05

...., Ltd Panther T&H Industry Co. Ltd PSGT Trading Jingjiang Ltd Qingdao Free Trade Zone Health Intl... Co., Ltd.; (4) Shanghai Furen International Trading; and (5) Shanghai Printing and Packaging...., Ltd Ningbo Pal International Trading Co. Ningbo Qunli Fastener Manufacture Co., Ltd Ningbo Shuanglin...

Quick-connect fasteners for assembling devices in space

NASA Technical Reports Server (NTRS)

Wesselski, Clarence J. (Inventor); Evenson, Erik E. (Inventor); Ruiz, Steve L. (Inventor)

1992-01-01

A quick-connect fastener of a relatively-simple straightforward design is arranged with a tubular body adapted to be engaged against an attachment fitting in coincidental alignment with an opening in that fitting. A tubular collet having flexible finger projecting from its forward end is arranged in the fastener body to be shifted forwardly by an elongated expander member coaxially arranged within the tubular collet for advancing the collet fingers into the opening in the attachment fitting. Biasing means are arranged between the elongated expander member and a rotatable actuator which is threadedly mounted within the tubular collet so as to be rotated for urging the expander member into engagement with the collet fingers. A first coupling member is arranged on the rotatable actuator to be accessible from outside of the fastener so that a second coupling member on the distal end of a flexible shaft can be introduced into the fastener body and coupled to the first coupling member to enable a typical actuating tool coupled to the shaft outside of the fastener body to be operated for advancing the outwardly-enlarged ends of the collet fingers into the opening in the attachment fitting and thereafter rotating the actuator member to expand the fingers to that attachment fitting. Upon expansion of the collet fingers, the biasing means impose a biasing force on the expander to releasably retain the fingers in their latching positions.

Motor-driven screwing and transporting tool for reactor pressure vessel head retaining fastenings

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

Scholz, M.

1977-09-13

The invention concerns a motor-driven screwing and transporting tool for tightening or loosening the threaded studs and associated tightening nuts of the head bolting of pressure vessels. After the tightening nuts are loosened or before they are tightened, the weight of the studs is taken over by rotating bearings that can be lifted, so that the studs with their tightening nuts can be screwed in or out, the screw threads of the studs being thus weight-relieved. The invention is intended primarily for nuclear reactor pressure vessels. 21 claims, 6 figures.

Tool for Guiding An Auger

NASA Technical Reports Server (NTRS)

Wesselski, C. J.

1983-01-01

Auger and Ram have same pitch, which minimizes damage to workpiece and load carried by auger. Auger firmly fastened onto ram shaft by screw and kept from rotating on shaft by slot machined into end of stem and male driving lug that engages slot. Used to install threaded studs in plastic or rubber where impractical to mold them in.

Mechanical coupling for a rotor shaft assembly of dissimilar materials

DOEpatents

Shi, Jun [Glastonbury, CT; Bombara, David [New Hartford, CT; Green, Kevin E [Broad Brook, CT; Bird, Connic [Rocky Hill, CT; Holowczak, John [South Windsor, CT

2009-05-05

A mechanical coupling for coupling a ceramic disc member to a metallic shaft includes a first wedge clamp and a second wedge clamp. A fastener engages a threaded end of a tie-bolt to sandwich the ceramic disc between the wedge clamps. An axial spring is positioned between the fastener and the second wedge clamp to apply an axial preload along the longitudinal axis. Another coupling utilizes a rotor shaft end of a metallic rotor shaft as one wedge clamp. Still another coupling includes a solid ceramic rotor disc with a multiple of tie-bolts radially displaced from the longitudinal axis to exert the preload on the solid ceramic rotor disc.

21 CFR 888.3060 - Spinal intervertebral body fixation orthosis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... each of a series of vertebral bodies. An eye-type screw is inserted in a hole in the center of each of the plates. A braided cable is threaded through each eye-type screw. The cable is tightened with a tension device and it is fastened or crimped at each eye-type screw. The device is used to apply force to...

21 CFR 888.3060 - Spinal intervertebral body fixation orthosis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... each of a series of vertebral bodies. An eye-type screw is inserted in a hole in the center of each of the plates. A braided cable is threaded through each eye-type screw. The cable is tightened with a tension device and it is fastened or crimped at each eye-type screw. The device is used to apply force to...

Rolled-out collectors

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

Shurcliff, W.A.

1979-04-01

SolaRoll is a solar collector material composed of extruded strips of black ethylene propylene diene monomer (EPDM) that is suitable for water or air type collectors. SolaRoll is provided in rolls and consists of an absorber mat with tubes and fins and a framing strip comprising all the parts of the collector frame. The rolls are bent in a counterflow pattern to cover the entire collector area and the mat is fastened with a thermosetting mastic adhesive. The heat transfer fluid is plain water as freezing does not injure the EPDM. Installation of the glazing in the framing strip ismore » described. EPDM has the disadvantage of low thermal conductivity but its use does not require antifreeze or a heat exchanger. Design options and suitable applications of SolaRoll systems are discussed.« less

Remote vacuum or pressure sealing device and method for critical isolated systems

DOEpatents

Brock, James David [Newport News, VA; Keith, Christopher D [Newport News, VA

2012-07-10

A remote vacuum or pressure sealing apparatus and method for making a radiation tolerant, remotely prepared seal that maintains a vacuum or pressure tight seal throughout a wide temperature range. The remote sealing apparatus includes a fixed threaded sealing surface on an isolated system, a gasket, and an insert consisting of a plug with a protruding sample holder. An insert coupling device, provided for inserting samples within the isolated system, includes a threaded fastener for cooperating with the fixed threaded sealing surface on the isolated system. The insert coupling device includes a locating pin for azimuthal orientation, coupling pins, a tooted coaxial socket wrench, and an insert coupling actuator for actuating the coupling pins. The remote aspect of the sealing apparatus maintains the isolation of the system from the user's environment, safely preserving the user and the system from detrimental effect from each respectively.

Electrochemical polishing of thread fastener test specimens of nickel-chromium iron alloys

DOEpatents

Kephart, Alan R.

1991-01-01

An electrochemical polishing device and method for selective anodic dissolution of the surface of test specimens comprised, for example, of nickel-chromium-iron alloys, which provides for uniform dissolution at the localized sites to remove metal through the use of a coiled wire electrode (cathode) placed in the immediate proximity of the working, surface resulting in a polished and uniform grain boundary.

Thermal insulating conformal blanket

NASA Technical Reports Server (NTRS)

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

2003-01-01

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

Tensiometer with removable wick

DOEpatents

Gee, Glendon W.; Campbell, Melvin D.

1992-01-01

The present invention relates to improvements in tensiometers for measuring soil water tension comprising a rod shaped wick. the rod shaped wick is shoestring, rolled paper towel, rolled glass microfiber filter, or solid ceramic. The rod shaped wick is secured to the tensiometer by a cone washer and a threaded fitting.

Tensiometer with removable wick

DOEpatents

Gee, G.W.; Campbell, M.D.

1992-04-14

The present invention relates to improvements in tensiometers for measuring soil water tension comprising a rod shaped wick. The rod shaped wick is a shoestring, rolled paper towel, rolled glass microfiber filter, or solid ceramic. The rod shaped wick is secured to the tensiometer by a cone washer and a threaded fitting. 2 figs.

Flexible horseshoe

DOEpatents

Ford, Donald F.

1985-01-01

A screw-on horseshoe formed from a plastic material is disclosed. A flex joint is provided that allows the horseshoe to expand and contract as pressure is applied to the horse's hoof, thereby reducing friction between the hoof and the shoe. The horseshoe also provides a lip portion projecting upwardly from a horseshoe base portion to protect the horse hoof wall from obstacles encountered during the movement of the horse. A novel screw having a double helix thread pattern including a high thread pattern and a low thread pattern is used to fasten the horseshoe to the horse's hoof without piercing the hoof wall. The screw includes a keyed recessed self-holding head that is complementary to, and therefore readily driven by, a power drill. A lightweight, yet wear-resistant, horseshoe that is readily attached to a horse's hoof with a minimum amount of labor and a minimum amount of damage to the hoof that can be constructed in many styles and sizes to match a large variety of horse uses is thus described.

Cadmium Alternatives for High-Strength Steel JTP - Phase 2

DTIC Science & Technology

2008-02-27

Project Overview Objective • Assess DoD- selected Cadmium alternatives in accordance with the DoD-approved Joint Test Protocol (JTP) for both...HE and adhesion testing): NAVAIR (complete) – Phase II (JTP test matrix): AFRL/CTC – Phase III (Testing for Threaded Fasteners): ARL • Selection of...Curry • Hill AFB – Mr. Nate Hughes • Alumiplate – Mr. Gus Vallejo • Marshall Labs – Mr. John Marshall U.S. AIR FORCE Phase I Overview and Selection

Pv-Thermal Solar Power Assembly

DOEpatents

Ansley, Jeffrey H.; Botkin, Jonathan D.; Dinwoodie, Thomas L.

2001-10-02

A flexible solar power assembly includes a flexible photovoltaic device attached to a flexible thermal solar collector. The solar power assembly can be rolled up for transport and then unrolled for installation on a surface, such as the roof or side wall of a building or other structure, by use of adhesive and/or other types of fasteners.

Fastener starter tool

NASA Technical Reports Server (NTRS)

Chandler, Faith T. (Inventor); Arnett, Michael C. (Inventor); Garton, Harry L. (Inventor); Valentino, William D. (Inventor)

2003-01-01

A fastener starter tool includes a number of spring retention fingers for retaining a small part, or combination of parts. The tool has an inner housing, which holds the spring retention fingers, a hand grip, and an outer housing configured to slide over the inner housing and the spring retention fingers toward and away from the hand grip, exposing and opening, or respectively, covering and closing, the spring retention fingers. By sliding the outer housing toward (away from) the hand grip, a part can be released from (retained by) the tool. The tool may include replaceable inserts, for retaining parts, such as screws, and configured to limit the torque applied to the part, to prevent cross threading. The inner housing has means to transfer torque from the hand grip to the insert. The tool may include replaceable bits, the inner housing having means for transferring torque to the replaceable bit.

Grace Under Pressure

NASA Technical Reports Server (NTRS)

2002-01-01

Developed in response to a NASA requirement to remotely measure tension in critical bolts on the International Space Station, the SureBolt(TM) Correlation Bolt Gage is the first ultrasonic system to capture an entire "echo" pulse for determining the change in time of flight of an ultrasonic signal traversing a fastener for tension measurement. The standard SureBolt system hardware has the capability of recording over 1 million bolt tension readings-with their complete waveforms-in Microsoft Excel-compatible format. The user- friendly Tension-Not-Torque(Copyright) software interface offers tension change graphing in real time, and a place to store field notes, special parameters, tension calibration constants, and temperature changes for each measurement. The technology has been used on fasteners as small as fine-threaded, 1-inch bolts, and as large as 18-inch-diameter by 30-foot-long tie rods. SureBolt is finding increased application within NASA and the aerospace industry, as well as in the automotive and nuclear industries.

Orion - Super Koropon(Registered Trademark) Torque/Tension Report

NASA Technical Reports Server (NTRS)

Hemminger, Edgar G.; McLeod, Christopher; Peil, John

2012-01-01

The primary objective of this testing was to obtain torque tension data for the use of Super Koropon Primer Base which was proposed for use on the Orion project. This compound is a corrosion inhibitor/sealer used on threaded fasteners and inserts as specified per NASA/JSC PRC-4004, Sealing of Joints and Faying Surfaces. Some secondary objectives of this testing, were to identify the effect on torque coefficient of several variables. This document contains the outcome of the testing.

Process Sensitivity, Performance, and Direct Verification Testing of Adhesive Locking Features

NASA Technical Reports Server (NTRS)

Golden, Johnny L.; Leatherwood, Michael D.; Montoya, Michael D.; Kato, Ken A.; Akers, Ed

2012-01-01

Phase I: The use of adhesive locking features or liquid locking compounds (LLCs) (e.g., Loctite) as a means of providing a secondary locking feature has been used on NASA programs since the Apollo program. In many cases Loctite was used as a last resort when (a) self-locking fasteners were no longer functioning per their respective drawing specification, (b) access was limited for removal & replacement, or (c) replacement could not be accomplished without severe impact to schedule. Long-term use of Loctite became inevitable in cases where removal and replacement of worn hardware was not cost effective and Loctite was assumed to be fully cured and working. The NASA Engineering & Safety Center (NESC) and United Space Alliance (USA) recognized the need for more extensive testing of Loctite grades to better understand their capabilities and limitations as a secondary locking feature. These tests, identified as Phase I, were designed to identify processing sensitivities, to determine proper cure time, the correct primer to use on aerospace nutplate, insert and bolt materials such as A286 and MP35N, and the minimum amount of Loctite that is required to achieve optimum breakaway torque values. The .1900-32 was the fastener size tested, due to wide usage in the aerospace industry. Three different grades of Loctite were tested. Results indicate that, with proper controls, adhesive locking features can be successfully used in the repair of locking features and should be considered for design. Phase II: Threaded fastening systems used in aerospace programs typically have a requirement for a redundant locking feature. The primary locking method is the fastener preload and the traditional redundant locking feature is a self-locking mechanical device that may include deformed threads, non-metallic inserts, split beam features, or other methods that impede movement between threaded members. The self-locking resistance of traditional locking features can be directly verified during assembly by measuring the dynamic prevailing torque. Adhesive locking features or LLCs are another method of providing redundant locking, but a direct verification method has not been used in aerospace applications to verify proper installation when using LLCs because of concern for damage to the adhesive bond. The reliability of LLCs has also been questioned due to failures observed during testing with coupons for process verification, although the coupon failures have often been attributed to a lack of proper procedures. It is highly desirable to have a direct method of verifying the LLC cure or bond integrity. The purpose of the Phase II test program was to determine if the torque applied during direct verification of an adhesive locking feature degrades that locking feature. This report documents the test program used to investigate the viability of such a direct verification method. Results of the Phase II testing were positive, and additional investigation of direct verification of adhesive locking features is merited.

Z-2 Threaded Insert Design and Testing

NASA Technical Reports Server (NTRS)

Ross, Amy; Rhodes, Richard; Jones, Robert J.; Graziosi, David; Ferl, Jinny; Sweeny, Mitch; Scarborough, Stephen

2016-01-01

NASA's Z-2 prototype space suit contains several components fabricated from an advanced hybrid composite laminate consisting of IM10 carbon fiber and fiber glass. One requirement was to have removable, replaceable helicoil inserts to which other suit components would be fastened. An approach utilizing bonded in inserts with helicoils inside of them was implemented. During initial assembly, cracking sounds were heard followed by the lifting of one of the blind inserts out of its hole when the screws were torqued. A failure investigation was initiated to understand the mechanism of the failure. Ultimately, it was determined that the pre-tension caused by torqueing the fasteners is a much larger force than induced from the pressure loads of the suit which was not considered in the insert design. Bolt tension is determined by dividing the torque on the screw by a k value multiplied by the thread diameter of the bolt. The k value is a factor that accounts for friction in the system. A common value used for k for a non-lubricated screw is 0.2. The k value can go down by as much as 0.1 if the screw is lubricated which means for the same torque, a much larger tension could be placed on the bolt and insert. This paper summarizes the failure investigation that was performed to identify the root cause of the suit failure and details how the insert design was modified to resist a higher pull out tension.

PV/thermal solar power assembly

DOEpatents

Ansley, Jeffrey H.; Botkin, Jonathan D.; Dinwoodie, Thomas L.

2004-01-13

A flexible solar power assembly (2) includes a flexible photovoltaic device (16) attached to a flexible thermal solar collector (4). The solar power assembly can be rolled up for transport and then unrolled for installation on a surface, such as the roof (20, 25) or side wall of a building or other structure, by use of adhesive and/or other types of fasteners (23).

Spline screw multiple rotations mechanism

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

1993-01-01

A system for coupling two bodies together and for transmitting torque from one body to another with mechanical timing and sequencing is reported. The mechanical timing and sequencing is handled so that the following criteria are met: (1) the bodies are handled in a safe manner and nothing floats loose in space, (2) electrical connectors are engaged as long as possible so that the internal processes can be monitored throughout by sensors, and (3) electrical and mechanical power and signals are coupled. The first body has a splined driver for providing the input torque. The second body has a threaded drive member capable of rotation and limited translation. The embedded drive member will mate with and fasten to the splined driver. The second body has an embedded bevel gear member capable of rotation and limited translation. This bevel gear member is coaxial with the threaded drive member. A compression spring provides a preload on the rotating threaded member, and a thrust bearing is used for limiting the translation of the bevel gear member so that when the bevel gear member reaches the upward limit of its translation the two bodies are fully coupled and the bevel gear member then rotates due to the input torque transmitted from the splined driver through the threaded drive member to the bevel gear member. An output bevel gear with an attached output drive shaft is embedded in the second body and meshes with the threaded rotating bevel gear member to transmit the input torque to the output drive shaft.

Bending at the base of a dragged-out viscous thread

NASA Astrophysics Data System (ADS)

Blount, Maurice; Lister, John

2007-11-01

We consider steady flow of a slender viscous thread falling from a nozzle onto a moving horizontal belt. We analyse the asymptotic limit of a very slender thread, and show that it has a boundary-layer structure in which bending stresses only become important near the belt, where they support a vertical stress and allow the velocity and rolling conditions to be satisfied. The outer solution is analogous to a viscous catenary, with velocity fixed at the belt and at the nozzle. There are three asymptotic regimes, with distinct structures, corresponding to the cases that the belt speed is larger than, smaller than, or close to the velocity of a freely falling thread. The implications for the onset and amplitude of meanders in the `fluid-mechanical sewing machine' are explored.

Fastener load tests and retention systems tests for cryogenic wind-tunnel models

NASA Technical Reports Server (NTRS)

Wallace, J. W.

1984-01-01

A-286 stainless steel screws were tested to determine the tensile load capability and failure mode of various screw sizes and types at both cryogenic and room temperature. Additionally, five fastener retention systems were tested by using A-286 screws with specimens made from the primary metallic alloys that are currently used for cryogenic models. The locking system effectiveness was examined by simple no-load cycling to cryogenic temperatures (-275 F) as well as by dynamic and static loading at cryogenic temperatures. In general, most systems were found to be effective retention devices. There are some differences between the various devices with respect to ease of application, cleanup, and reuse. Results of tests at -275 F imply that the cold temperatures act to improve screw retention. The improved retention is probably the result of differential thermal contraction and/or increased friction (thread-binding effects). The data provided are useful in selecting screw sizes, types, and locking devices for model systems to be tested in cryogenic wind tunnels.

Membrane Tension Control

NASA Technical Reports Server (NTRS)

Su, Ji (Inventor); Harrison, Joycelyn S. (Inventor)

2005-01-01

An electrostrictive polymer actuator comprises an electrostrictive polymer with a tailorable Poisson's ratio. The electrostrictive polymer is electroded on its upper and lower surfaces and bonded to an upper material layer. The assembly is rolled tightly and capped at its ends. In a membrane structure having a membrane, a supporting frame and a plurality of threads connecting the membrane to the frame, an actuator can be integrated into one or more of the plurality of threads. The electrostrictive polymer actuator displaces along its longitudinal axis, thereby affecting movement of the membrane surface.

An ultrasonic technique for measuring stress in fasteners

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

Stevens, K. J.; Day, P.; Byron, D.

1999-12-02

High temperature bolting alloys are extensively used in the thermal power generation industry as for example, reheat ESV and Governor valve studs. Remnant life assessment methodologies and plant maintenance procedures require the monitoring of the operational stress levels in these fasteners. Some conventional ultrasonic techniques require longitudinal wave measurements to be undertaken when the nut on the bolt is loosened and then re-tightened. Other techniques use a combination of shear waves and longitudinal waves. In this paper, the problems and pitfalls associated with various ultrasonic techniques for measuring stress in bolts, is discussed. An ultrasonic technique developed for measuring themore » stress in Durehete 1055 bolts is presented. Material from a textured rolled bar has been used as a test bed in the development work. The technique uses shear wave birefringence and compression waves at several frequencies to measure texture, fastener length and the average stress. The technique was developed by making ultrasonic measurements on bolts tensioned in universal testing machines and a hydraulic nut. The ultrasonic measurements of residual stress have been checked against strain gauge measurements. The Durehete bolts have a hollow cylinder geometry of restricted dimensions, which significantly alters compression and shear wave velocities from bulk values and introduces hoop stresses which can be measured by rotating the polarization of the shear wave probe. Modelling of the experimental results has been undertaken using theories for the elastic wave propagation through waveguides. The dispersion equations allow the velocity and length of the fastener to be measured ultrasonically in some situations where the length of the fastener can not be measured directly with a vernier caliper or micrometer and/or where it is undesirable to loosen nuts to take calibration readings of the shear and compression wave velocities.« less

Production Engineering Program to Develop Improved Mass-Production Process for M42/M46 Grenade Bodies

DTIC Science & Technology

1978-03-01

J16 Photograph 3 Knurling Tool Installed in Machine . . ....... 16 Photograph 4 Shrapnel Pattern Being Knurled Into M42 Grenade Cylinder...body Fenn mill embossing rolls. Roehlen was awarded a cuxiu**L am’i labricated a knurling tool for use in the modified Tesker thread-rolling machine ...automatic grinding machine . IKratz-Wilde was not successful in developing tooling to produce domes to the inertia-welded assembly design. (See Figure

Evaluation of replacement thread lubricants for red lead and graphite in mineral oil

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

Jungling, T.L.; Rauth, D.R.; Goldberg, D.

1998-04-30

Eight commercially available thread lubricants were evaluated to determine the best replacement for Red Lead and Graphite in Mineral Oil (RLGMO). The evaluation included coefficient of friction testing, high temperature anti-seizing testing, room temperature anti-galling testing, chemical analysis for detrimental impurities, corrosion testing, off-gas testing, and a review of health and environmental factors. The coefficient of friction testing covered a wide variety of factors including stud, nut, and washer materials, sizes, manufacturing methods, surface coatings, surface finishes, applied loads, run-in cycles, and relubrication. Only one lubricant, Dow Corning Molykote P37, met all the criteria established for a replacement lubricant. Itmore » has a coefficient of friction range similar to RLGMO. Therefore, it can be substituted directly for RLGMO without changing the currently specified fastener torque values for the sizes, materials and conditions evaluated. Other lubricants did not perform as well as Molykote P37 in one or more test or evaluation categories.« less

The Study of Importance of the Balance Space Food -Storage Method -

NASA Astrophysics Data System (ADS)

Katayama, Naomi; Yamashita, Masamichi; Hashimoto, Hirofumi; Space Agriculture Task Force, J.

Providing foods to space crew is the important requirements to support long term manned space exploration. Foods fill not only physiological requirements to sustain life, but psychological needs for refreshment and joy during the long and hard mission to extraterrestrial planets. We designed joyful and healthy recipe with materials, which can be produced by the bio-regenerative agricultural system operated at limited resources available in Mars base, Moon base and spaceship. We need to think about how to use the storage food when we have the time of emergency. The pupa of the silkworm becomes the important nourishment source as protein and lipid. The silk thread uses it as clothing and cosmetics and medical supplies. However, we can use the silk thread as food as protein. The silk thread is mad of sericin and fibroin. The sericin is used for cosmetics mainly, but can make sheet food by mixing it with rice flour. We can make Japanese rolled sushi with this product. In addition, we can make spring roll and gyoza and shao-mai. As for the fibroin which is the subject of the silk thread, is to extract it high pressure heat; of the protein can powder it, and can use it as food. Even if there is the silk thread in this way after having made it clothes once, we can do it to food again. We can reuse the cotton thread as carbohydrates equally, too. We can use the wood as carbohydrates, also. Based upon the foregoing, we use the pupa of the silkworm as protein and lipid, and the silk thread as protein, and the cotton thread and wood as carbohydrates. It is recommended as healthy meal balance; Protein: Lipid: Carbohydrate ratio equal 15-20We succeeded to develop joyful and nutritious space recipe at the end. Since energy consumption for physical exercise activities under micro-or sub-gravity is less than the terrestrial case, choice of our space foods is essencial to suppress blood sugar level, and prevent the metabolic syndrome. Because of less need of agricultural resources at choosing ecological members from the lower ladder of the food chain, our space recipe could be a proposal to solve the food problem on Earth.

Hand-handle interface force and torque measurement system for pneumatic assembly tool operations: suggested enhancement to ISO 6544.

PubMed

Lin, Jia-Hua; McGorry, Raymond W; Chang, Chien-Chi

2007-05-01

A hand-handle interface force and torque measurement system is introduced to fill the void acknowledged in the international standard ISO 6544, which governs pneumatic, assembly tool reaction torque and force measurement. This system consists of an instrumented handle with a sensor capable of measuring grip force and reaction hand moment when threaded, fastener-driving tools are used by operators. The handle is rigidly affixed to the tool in parallel to the original tool handle allowing normal fastener-driving operations with minimal interference. Demonstration of this proposed system was made with tools of three different shapes: pistol grip, right angle, and in-line. During tool torque buildup, the proposed system measured operators exerting greater grip force on the soft joint than on the hard joint. The system also demonstrated that the soft joint demanded greater hand moment impulse than the hard joint. The results demonstrate that the measurement system can provide supplemental data useful in exposure assessment with power hand tools as proposed in ISO 6544.

Better Seals for Vacuum Bags

NASA Technical Reports Server (NTRS)

Penn, B.; Clemons, J. M.

1983-01-01

Roller tool spreads even layer of adhesive. Tool easily constructed from metal, plastic, or wood. Sewing-thread spool serves as roller, nail as axle, and jigsawed block of wood as handle. Tool rolled and pressed against plastic film to assure even layer of adhesive around periphery.

The study of importance of the storage method of the space foods

NASA Astrophysics Data System (ADS)

Katayama, Naomi; Yamashita, Masamichi; Space Agriculture Task Force, J.

Providing foods to space crew is the important requirements to support long term manned space exploration. Foods fill not only physiological requirements to sustain life, but psychological needs for refreshment and joy during the long and hard mission to extraterrestrial planets. In the space stay of the long term, the storage technology of the food is important. Surplus food and the establishment of a safe save method of the food are essential. However, in Moon and Mars base or spaceship, there are limited spaces. We need to think about how to use the storage food when we have the time of emergency. The fundamental composition of our recipe is unpolished rice, barley, soybean, sweat potato and green-yellow vegetables. Supplement food materials to fulfill the nutritional requirements we chose are loach, silkworm pupa, termite, snail, mud snail, bee, cassava and quinoa. The pupa of the silkworm becomes the important nourishment source as protein and lipid. The silk thread uses it as clothing and cosmetics and medical supplies. However, we can use the silk thread as food as protein. The silk thread is mad of sericin and fibroin. The sericin is used for cosmetics mainly, but can make sheet food by mixing it with rice flour. We can make Japanese rolled sushi with this product. In addition, we can make spring roll and gyoza and shao-mai. As for the fibroin which is the subject of the silk thread, is to extract it high pressure heat; of the protein can powder it, and can use it as food. Even if there is the silk thread in this way after having made it clothes once, we can do it to food again. We can reuse the cotton thread as carbohydrates equally, too. We can use the wood as carbohydrates, also. Based upon the foregoing, we use the pupa of the silkworm as protein and lipid, and the silk thread as protein, and the cotton thread and wood as carbohydrates. It is recommended as healthy meal balance; Protein: Lipid: Carbohydrate ratio equal 15We succeeded to develop joyful and nutritious space recipe at the end. In addition, we were able to perform new suggestion about the storage of the food. We use clothes or furniture as a farm of the food, and it is an idea offering as food again if necessary. Because of less need of agricultural resources at choosing ecological members from the lower ladder of the food chain, our space recipe could be a proposal to solve the food problem on Earth.

Protective interior wall and attach8ing means for a fusion reactor vacuum vessel

DOEpatents

Phelps, Richard D.; Upham, Gerald A.; Anderson, Paul M.

1988-01-01

An array of connected plates mounted on the inside wall of the vacuum vessel of a magnetic confinement reactor in order to provide a protective surface for energy deposition inside the vessel. All fasteners are concealed and protected beneath the plates, while the plates themselves share common mounting points. The entire array is installed with torqued nuts on threaded studs; provision also exists for thermal expansion by mounting each plate with two of its four mounts captured in an oversize grooved spool. A spool-washer mounting hardware allows one edge of a protective plate to be torqued while the other side remains loose, by simply inverting the spool-washer hardware.

ROTATING MOTIONS AND MODELING OF THE ERUPTING SOLAR POLAR-CROWN PROMINENCE ON 2010 DECEMBER 6

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

Su, Yingna; Van Ballegooijen, Adriaan, E-mail: ynsu@head.cfa.harvard.edu

2013-02-10

A large polar-crown prominence composed of different segments spanning nearly the entire solar disk erupted on 2010 December 6. Prior to the eruption, the filament in the active region part split into two layers: a lower layer and an elevated layer. The eruption occurs in several episodes. Around 14:12 UT, the lower layer of the active region filament breaks apart: One part ejects toward the west, while the other part ejects toward the east, which leads to the explosive eruption of the eastern quiescent filament. During the early rise phase, part of the quiescent filament sheet displays strong rolling motionmore » (observed by STEREO-B) in the clockwise direction (viewed from east to west) around the filament axis. This rolling motion appears to start from the border of the active region, then propagates toward the east. The Atmospheric Imaging Assembly (AIA) observes another type of rotating motion: In some other parts of the erupting quiescent prominence, the vertical threads turn horizontal, then turn upside down. The elevated active region filament does not erupt until 18:00 UT, when the erupting quiescent filament has already reached a very large height. We develop two simplified three-dimensional models that qualitatively reproduce the observed rolling and rotating motions. The prominence in the models is assumed to consist of a collection of discrete blobs that are tied to particular field lines of a helical flux rope. The observed rolling motion is reproduced by continuous twist injection into the flux rope in Model 1 from the active region side. Asymmetric reconnection induced by the asymmetric distribution of the magnetic fields on the two sides of the filament may cause the observed rolling motion. The rotating motion of the prominence threads observed by AIA is consistent with the removal of the field line dips in Model 2 from the top down during the eruption.« less

Multithreaded Stochastic PDES for Reactions and Diffusions in Neurons.

PubMed

Lin, Zhongwei; Tropper, Carl; Mcdougal, Robert A; Patoary, Mohammand Nazrul Ishlam; Lytton, William W; Yao, Yiping; Hines, Michael L

2017-07-01

Cells exhibit stochastic behavior when the number of molecules is small. Hence a stochastic reaction-diffusion simulator capable of working at scale can provide a more accurate view of molecular dynamics within the cell. This paper describes a parallel discrete event simulator, Neuron Time Warp-Multi Thread (NTW-MT), developed for the simulation of reaction diffusion models of neurons. To the best of our knowledge, this is the first parallel discrete event simulator oriented towards stochastic simulation of chemical reactions in a neuron. The simulator was developed as part of the NEURON project. NTW-MT is optimistic and thread-based, which attempts to capitalize on multi-core architectures used in high performance machines. It makes use of a multi-level queue for the pending event set and a single roll-back message in place of individual anti-messages to disperse contention and decrease the overhead of processing rollbacks. Global Virtual Time is computed asynchronously both within and among processes to get rid of the overhead for synchronizing threads. Memory usage is managed in order to avoid locking and unlocking when allocating and de-allocating memory and to maximize cache locality. We verified our simulator on a calcium buffer model. We examined its performance on a calcium wave model, comparing it to the performance of a process based optimistic simulator and a threaded simulator which uses a single priority queue for each thread. Our multi-threaded simulator is shown to achieve superior performance to these simulators. Finally, we demonstrated the scalability of our simulator on a larger CICR model and a more detailed CICR model.

Size distributions and exposure concentrations of nanoparticles associated with the emissions of oil mists from fastener manufacturing processes.

PubMed

Wang, Ying-Fang; Tsai, Perng-Jy; Chen, Chun-Wan; Chen, Da-Ren; Dai, Yu-Tung

2011-12-30

The aims of the present study were set out to measure size distributions and estimate workers' exposure concentrations of oil mist nanoparticles in three selected workplaces of the forming, threading, and heat treating areas in a fastener manufacturing plant by using a modified electrical aerosol detector (MEAD). The results were further compared with those simultaneously obtained from a nanoparticle surface area monitor (NSAM) and a scanning mobility particle sizer (SMPS) for the validation purpose. Results show that oil mist nanoparticles in the three selected process areas were formed mainly through the evaporation and condensation processes. The measured size distributions of nanoparticles were consistently in the form of uni-modal. The estimated fraction of nanoparticles deposited on the alveolar (AV) region was consistently much higher than that on the head airway (HD) and tracheobronchial (TB) regions in both number and surface area concentration bases. However, a significant difference was found in the estimated fraction of nanoparticles deposited on each individual region while different exposure metrics were used. Comparable results were found between results obtained from both NSAM and MEAD. After normalization, no significant difference can be found between the results obtained from SMPS and MEAD. It is concluded that the obtained MEAD results are suitable for assessing oil mist nanoparticle exposures. Copyright © 2011 Elsevier B.V. All rights reserved.

Pressure Roller For Tape-Lift Tests

NASA Technical Reports Server (NTRS)

Abrams, Eve

1991-01-01

Rolling device applies nearly constant, uniform pressure to surface. Simple tool exerts nearly constant pressure via compression of sheath by fixed amount. Pins hold wheels on cylinder and cylinder on tangs of handle. Cylinder and handle made of metal or plastic. Sheath press-fit or glued to cylinder. End pins attached to cylinder by adhesive or screw threads. Device intended for use in taking tape-lift samples of particulate contamination on surface.

Source of the slippage in the universal joints of the Hoffmann external fixator.

PubMed

Drijber, F L; Finlay, J B; Moroz, T K; Rorabeck, C H

1990-01-01

An investigation was conducted to determine what improvements in the resistance to slippage could be obtained in selected interfaces (rod/clip torsional, cheek/bowl and cheek/clip) of the Hoffmann external fixator. The modification involved changing the standard wing-nut clamp for a bolt with a thread of 7 mm and a 1 mm pitch and placing an FAG 28-303 thrust-bearing (needle roller and cage assembly) between the bolt and the cheek. The results showed a significant improvement in the slippage values of all interfaces; increases of approximately six times were obtained at all torque values of the wing-nut clamp or fastener tested. Such improvements would markedly increase the reliability of external fixation systems and thus reduce the incidence of loss-of-reduction of fracture due to slippage of the universal joint.

Fasteners and fastening techniques: A compilation

NASA Technical Reports Server (NTRS)

1972-01-01

Technology on fasteners and fastening devices is presented, as part of NASA's TU program to provide technical information on devices, methods, and techniques resulting from aerospace research. The material is divided into two sections which include: (1) data concerning a selected group of fasteners and concept for fasteners such as locking devices, couplings, and connect and release mechanisms; and (2) discussions on a number of fastening techniques such as those for mounting panel lamps, clamping flange bolts, stretching fasteners, and transferring fuel from a tanker to another vehicle.

Self-locking double retention redundant pull pin release

NASA Technical Reports Server (NTRS)

Killgrove, Thomas O. (Inventor)

1987-01-01

A double-retention redundant pull pin release system is disclosed. The system responds to a single pull during an intentional release operation. A spiral-threaded main pin is seated in a mating bore in a housing, which main pin has a flange fastened thereon at the part of the main pin which is exterior to the housing. Accidental release tends to rotate the main pin. A secondary pin passes through a slightly oversized opening in the flange and is seated in a second bore in the housing. The pins counteract against one another to prevent accidental release. A frictional lock is shared between the main and secondary pins to enhance further locking of the system. The secondary pin, in response to a first pull, is fully retracted from its bore and flange hole. Thereafter the pull causes the main pin to rotate free of the housing to release, for example, a parachute mechanism.

Nuclear reactor alignment plate configuration

DOEpatents

Altman, David A; Forsyth, David R; Smith, Richard E; Singleton, Norman R

2014-01-28

An alignment plate that is attached to a core barrel of a pressurized water reactor and fits within slots within a top plate of a lower core shroud and upper core plate to maintain lateral alignment of the reactor internals. The alignment plate is connected to the core barrel through two vertically-spaced dowel pins that extend from the outside surface of the core barrel through a reinforcement pad and into corresponding holes in the alignment plate. Additionally, threaded fasteners are inserted around the perimeter of the reinforcement pad and into the alignment plate to further secure the alignment plate to the core barrel. A fillet weld also is deposited around the perimeter of the reinforcement pad. To accomodate thermal growth between the alignment plate and the core barrel, a gap is left above, below and at both sides of one of the dowel pins in the alignment plate holes through with the dowel pins pass.

Cadmium plating replacements

NASA Technical Reports Server (NTRS)

Nelson, Mary J.; Groshart, Earl C.

1995-01-01

The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

PRECISION TIME-DELAY GENERATOR

DOEpatents

Carr, B.J.; Peckham, V.D.

1959-06-16

A precision time-delay generator circuit with low jitter is described. The first thyratron has a series resonant circuit and a diode which is connected to the second thyratron. The first thyratron is triggered at the begin-ning of a time delay and a capacitor is discharged through the first thyratron and the diode, thereby, triggering the second thyratron. (T.R.H.) l6l9O The instrument described can measure pressures between sea level and 300,000 ft. The pressure- sensing transducer of the instrument is a small cylindrical tube with a thin foil of titanium-tritium fastened around the inside of the tube. Output is a digital signal which can be used for storage or telemetering more conveniently than an analog signal. (W.D.M.) l6l9l An experimental study was made on rolling contacts in the temperature range of 550 to 1000 deg F. Variables such as material composition, hardness, and operating conditions were investigated in a rolling test stand. Ball bearing tests were run to determine the effect of design parameters, bearing materials, lubricants, and operating conditions. (auth)

Internal impacted screw-locking pellet

NASA Technical Reports Server (NTRS)

MacMartin, Malcolm J. (Inventor)

1994-01-01

An elongate fastener having an engaging surface engageable with an engaging surface of a fastener's mate includes a hole extending through a portion of the fastener and having a top opening and a bottom floor, a locking pellet disposed near the bottom floor, a discharge channel communicating between the pellet and through the engaging surface of the fastener and opening out toward the engaging surface of the fastener's mate, and an impact pin in the hole having a top portion protruding through the top opening and a bottom portion near the locking pellet, whereby the pin drives the locking pellet through the discharge channel against the engaging surfaces of the fastener and the fastener's mate whereby to lock the fastener against the fastener's mate.

Rolling-circle amplification under topological constraints

PubMed Central

Kuhn, Heiko; Demidov, Vadim V.; Frank-Kamenetskii, Maxim D.

2002-01-01

We have performed rolling-circle amplification (RCA) reactions on three DNA templates that differ distinctly in their topology: an unlinked DNA circle, a linked DNA circle within a pseudorotaxane-type structure and a linked DNA circle within a catenane. In the linked templates, the single-stranded circle (dubbed earring probe) is threaded, with the aid of two peptide nucleic acid openers, between the two strands of double-stranded DNA (dsDNA). We have found that the RCA efficiency of amplification was essentially unaffected when the linked templates were employed. By showing that the DNA catenane remains intact after RCA reactions, we prove that certain DNA polymerases can carry out the replicative synthesis under topological constraints allowing detection of several hundred copies of a dsDNA marker without DNA denaturation. Our finding may have practical implications in the area of DNA diagnostics. PMID:11788721

Analysis of composite laminates with multiple fasteners by boundary collocation technique

NASA Astrophysics Data System (ADS)

Sergeev, Boris Anatolievich

Mechanical fasteners remain the primary means of load transfer between structural components made of composite laminates. As, in pursuit of increasing efficiency of the structure, the operational load continues to grow, the load carried by each fastener increases accordingly. This accelerates initiation of fatigue-related cracks near the fasteners holes and increases probability of failure. Therefore, the assessment of the stresses around the fastener holes and the stress intensity factors associated with edge cracks becomes critical for damage-tolerant design. Because of the presence of unknown contact stresses and the contact region between the fastener and the laminate, the analysis of a pin-loaded hole becomes considerably more complex than that of a traction-free hole. The accurate prediction of the contact stress distribution along the hole boundary is critical for determining the stress intensity factors and is essential for reliable strength evaluation and failure prediction. This study concerns the development of an analytical methodology, based on the boundary collocation technique, to determine the contact stresses and stress intensity factors required for strength and life prediction of bolted joints with many fasteners. It provides an analytical capability for determining the non-linear contact stresses in mechanically fastened composite laminates while capturing the effects of finite geometry, presence of edge cracks, interaction among fasteners, material anisotropy, fastener flexibility, fastener-hole clearance, friction between the pin and the laminate, and by-pass loading. Also, the proposed approach permits the determination of the fastener load distribution, which significantly influences the failure load of a multi-fastener joint. The well known phenomenon of the fastener tightening torque (clamping force) influence on the load distribution among the different fastener in a multi-fastener joints is taken into account by means of bi-linear representation of the elastic fastener deflection. Finally, two different failure criteria, maximum strains averaged over the characteristic distances and Tsai-Wu criterion, were used to predict the failure load and failure mode in two composite-aluminum joints. The comparison of the present predictions with the published experimental results reveals their agreement.

Separable fastening device

DOEpatents

Harvey, Andrew C.; Ribich, William A.; Marinaccio, Paul J.; Sawaf, Bernard E.

1987-12-01

A separable fastener system has a first separable member that includes a series of metal hook sheets disposed in stacked relation that defines an array of hook elements on its broad surface. Each hook sheet is a planar metal member of uniform thickness and has a body portion with a series of hook elements formed along one edge of the body. Each hook element includes a stem portion, a deflecting surface portion, and a latch portion. Metal spacer sheets are disposed between the hook sheets and may be varied in thickness and in number to control the density of the hook elements on the broad surface of the first fastener member. The hook and spacer sheets are secured together in stacked relation. A second fastener member has a surface of complementary engaging elements extending along its broad surface which are releasably interengageable with the hook elements of the first fastener member, the deflecting surfaces of the hook elements of the first fastener member tending to deflect hook engaging portions of the second fastener member and the latch portions of the hook elements of the first fastener member engaging portions of the second fastener member in fastening relation.

RFID Torque Sensing Tag System for Fasteners

NASA Technical Reports Server (NTRS)

Fink, Patrick W. (Inventor); Lin, Gregory Y. (Inventor); Ngo, Phong H. (Inventor); Kennedy, Timothy F. (Inventor)

2016-01-01

The present invention provides an RFID-based torque sensor that can be used to quickly monitor off the shelf fasteners including fasteners that are used in expensive satellites or other uses where fastener failure can be very costly. In one embodiment, an antenna, RFID ring and spring comprise a sensor tag that can be interrogated with an interrogation signal produced by an interrogator device. When sufficient torque is applied to the fastener, an RFID circuit is connected, and produces a radio frequency (RF) signal that can be read by the interrogator. In one embodiment, the RFID circuit does not transmit when the spring member is not compressed, thereby indicating insufficient tensioning of the fastener. The present invention offers the ability to remotely, quickly, and inexpensively verify that any number of fasteners are torqued properly upon initial installation. Where applicable, the present invention allows low cost monitoring over the life of the fastener.

Lunar rated fasteners

NASA Technical Reports Server (NTRS)

Gupton, Lindsey; Hyde, Steve; Mckillip, Dan; Player, Bryan; Smith, Greg

1988-01-01

A catalog of fasteners is presented for a variety of applications to be used in a lunar environment. The fastening applications targeted include: covers, panels, hatches, bearings, wheels, gears, pulleys, anchors for the lunar surface and structural fasteners (general duty preloadable). The robotic installation and removal of each fastener is presented along with a discussion of failure modes. Structural performance data is tabulated for various configurations. Potential materials for the space environment are presented along with recommendations of appropriate solid film lubricants. Three original fastener designs were found suitable for the lunar environment. A structural analysis is presented for each original design.

Two fault tolerant toggle-hook release

NASA Technical Reports Server (NTRS)

Graves, Thomas Joseph (Inventor); Brown, Christopher William (Inventor)

1991-01-01

A coupling device is disclosed which is mechanically two fault tolerant for release. The device comprises a fastener plate and fastener body, each of which is attachable to a different one of a pair of structures to be joined. The fastener plate and body are coupled by an elongate toggle mounted at one end in a socket on the fastener plate for universal pivotal movement thereon. The other end of the toggle is received in an opening in the fastener body and adapted for limited pivotal movement therein. The toggle is adapted to be restrained by three latch hooks arranged in symmetrical equiangular spacing about the axis of the toggle, each hook being mounted on the fastener body for pivotal movement between an unlatching non-contact position with respect to the toggle and a latching position in engagement with a latching surface of the toggle. The device includes releasable lock means for locking each latch hook in its latching position whereby the toggle couples the fastener plate to the fastener body and means for releasing the lock means to unlock each said latch hook from the latch position whereby the unlocking of at least one of the latch hooks from its latching position results in the decoupling of the fastener plate from the fastener body.

Delayed Collapse of Wooden Folding Stairs

NASA Astrophysics Data System (ADS)

Krentowski, Janusz; Chyzy, Tadeusz

2017-10-01

During operation of folding stairs, a fastener joining the ladder hanger with the frame was torn off. A person using the stairs sustained serious injury. In several dozen other locations similar accidents were observed. As a result of inspections, some threaded parts of the screws were found in the gaps between the wooden elements of the stairs’ flaps. In the construction a hatch made of wooden strips is attached to an external frame by means of metal hangers. Laboratory strength tests were conducted on three samples made of wooden elements identical to the ones used in the damaged stairs. Due to complex load distribution mechanism acting on the base of the structure, a three-dimensional FEM model was created. An original software was used for calculations. Five computational model variants were considered. As a result of the numerical analyses, it was unquestionably shown that faulty connections were the cause of the destruction of the stairs. The weakest link in the load transmission chain were found to have been the screws connecting the hatch board with the hangers.

Cryogenic-Compatible Winchester Connector Mount and Retaining System for Composite Tubes

NASA Technical Reports Server (NTRS)

Pontius, James; McGuffey, Douglas

2011-01-01

A connector retainer and mounting system has been designed to replace screw-mounting of Winchester connectors. Countersunk screws are normally used to secure connectors to structures, and to keep them from coming apart. These screws are normally put into threaded or through-holes in metallic structures. This unique retainer is designed such that integral posts keep the connector halves retained, and a groove permits a cable tie to be fastened around the retainer and composite tube, thus securing the connector to the structure. The system is compatible for use on cryogenic (and conventional) bonded composite tube assemblies. Screws and tapped/through-holes needed to retain and mount Winchester connectors cannot be used on blind-access composite tubes. This system allows for rapid installation, removal, low-molecular-outgassing materials, and particulate-free installation and removal. Installation and/or changes late in the integration, and test flow with limited access in a cleanroom environment are possible. No sanding or bonding is needed.

Theoretical basis for design of thermal-stress-free fasteners

NASA Technical Reports Server (NTRS)

Blosser, M. L.; Mcwithey, R. R.

1983-01-01

A theoretical basis was developed for the design of fasteners which are free of thermal stress. A fastener can be shaped to eliminate the thermal stress which would otherwise result from differential thermal expansion between dissimilar fastener and sheet materials for many combinations of isotropic and orthotropic materials. The resulting joint remains snug, yet free of thermal stress at any temperature, if the joint is uniform in temperature, if it is frictionless, and if the coefficients of thermal expansion of the materials do not change with temperature. In general, such a fastener has curved sides; however, if both materials have isotropic coefficients of thermal expansion, a conical fastener is free of thermal stress. Equations are presented for thermal stress free shapes at both initial and final temperature, and typical fastener shapes are shown.

The effect of fatigue cracks on fastener flexibility, load distribution, and fatigue crack growth

NASA Astrophysics Data System (ADS)

Whitman, Zachary Layne

Fatigue cracks typically occur at stress risers such as geometry changes and holes. This type of failure has serious safety and economic repercussions affecting structures such as aircraft. The need to prevent catastrophic failure due to fatigue cracks and other discontinuities has led to durability and damage tolerant methodologies influencing the design of aircraft structures. Holes in a plate or sheet filled with a fastener are common fatigue critical locations in aircraft structure requiring damage tolerance analysis (DTA). Often, the fastener is transferring load which leads to a loading condition involving both far-field stresses such as tension and bending, and localized bearing at the hole. The difference between the bearing stress and the tensile field at the hole is known as load transfer. The ratio of load transfer as well as the magnitude of the stresses plays a significant part in how quickly a crack will progress to failure. Unfortunately, the determination of load transfer in a complex joint is far from trivial. Many methods exist in the open literature regarding the analysis of splices, doublers and attachment joints to determine individual fastener loads. These methods work well for static analyses but greater refinement is needed for crack growth analysis. The first fastener in a splice or joint is typically the most critical but different fastener flexibility equations will all give different results. The constraint of the fastener head and shop end, along with the type of fastener, affects the stiffness or flexibility of the fastener. This in turn will determine the load that the fastener will transfer within a given fastener pattern. However, current methods do not account for the change in flexibility at a fastener as the crack develops. It is put forth that a crack does indeed reduce the stiffness of a fastener by changing its constraint, thus lessening the load transfer. A crack growth analysis utilizing reduced load transfer will result in a slower growing crack versus an analysis that ignores the effect.

Thermal-stress-free fasteners for joining orthotropic materials

NASA Technical Reports Server (NTRS)

Blosser, M. L.

1987-01-01

Hot structures fabricated from orthotropic materials are an attractive design option for future high speed vehicles. Joining subassemblies of these materials with standard cylindrical fasteners can lead to loose joints or highly stressed joints due to thermal stress. A method has been developed to eliminate thermal stresses and maintain a tight joint by shaping the fastener and mating hole. This method allows both materials (fastener and structure), with different coefficients of thermal expansion (CTEs) in each of the three material directions, to expand freely with temperature yet remain in contact. For the assumptions made in the analysis, the joint will remain snug, yet free of thermal stress at any temperature. Finite element analysis was used to verify several thermal-stress-free fasteners and to show that conical fasteners, which are thermal-stress-free for isotropic materials, can reduce thermal stresses for transversely isotropic materials compared to a cylindrical fastener. Equations for thermal-stress-free shapes are presented and typical fastener shapes are shown.

The Experiment and Numerical Simulation of Composite Countersunk-head Fasteners Pull-through Mechanical Behavior

NASA Astrophysics Data System (ADS)

Mu, Junwu; Guan, Zhidong; Bian, Tianya; Li, Zengshan; Wang, Kailun; Liu, Sui

2014-10-01

Fasteners made of the anisotropic carbon/carbon (C/C) composite material have been developed for joining C/C composite material components in the high-temperature environment. The fastener specimens are fabricated from the C/C composites which are made from laminated carbon cloths with Z-direction carbon fibers being punctured as perform. Densification process cycles such as the thermal gradient chemical vapor infiltration (CVI) technology were repeated to obtain high density C/C composites fastener. The fasteners were machined parallel to the carbon cloths (X-Y direction). A method was proposed to test pull-through mechanical behavior of the countersunk-head C/C composite material fasteners. The damage morphologies of the fasteners were observed through the charge coupled device (CCD) and the scanning electron microscope (SEM). The internal micro-structure were observed through the high-resolution Mirco-CT systems. Finally, an excellent simulation of the C/C composite countersunk-head fasteners were performed with the finite element method (FEM), in which the damage evolution model of the fastener was established based on continuum damage mechanics. The simulation is correspond well with the test result . The damage evolution process and the relation between the countersunk depth and the ultimate load was investigated.

76 FR 45540 - Fastener Quality Act Insignia Recordal Process

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-29

... DEPARTMENT OF COMMERCE United States Patent and Trademark Office Fastener Quality Act Insignia... Fastener Quality Act of 1999 (FQA), 15 U.S.C. 5401 et seq., certain industrial fasteners must bear an... Quality Act (PTO-1611), which provides manufacturers with a convenient way to [[Page 45541

Push/Push Fastener

NASA Technical Reports Server (NTRS)

Jackson, Steven A.

1996-01-01

Modified version of Nylatch (or equivalent) commerical quick-connect/quick-disconnect fastener for joining flat panels. Fastener tightened by pushing on knob on one side and loosened by pushing on knob on other side. Push/push operation of fastener advantageous in cold or otherwise hostile environments where gloves worn, in underwater operations, or if person handicapped.

Titanium fasteners. [for aircraft industry

NASA Technical Reports Server (NTRS)

Phillips, J. L.

1972-01-01

Titanium fasteners are used in large quantities throughout the aircraft industry. Most of this usage is in aluminum structure; where titanium structure exists, titanium fasteners are logically used as well. Titanium fasteners offer potential weight savings to the designer at a cost of approximately $30 per pound of weight saved. Proper and least cost usage must take into consideration type of fastener per application, galvanic couples and installation characteristics of protective coatings, cosmetic appearance, paint adhesion, installation forces and methods available and fatigue performance required.

Stress corrosion resistant fasteners

NASA Technical Reports Server (NTRS)

Roach, T. A.

1985-01-01

A family of high performance aerospace fasteners made from corrosion resistant alloys for use in applications where corrosion and stress-corrosion cracking are of major concern are discussed. The materials discussed are mainly A-286, Inconel 718, MP35N and MP159. Most of the fasteners utilize cold worked and aged materials to achieve the desired properties. The fasteners are unique in that they provide a combination of high strength and immunity to stress corrosion cracking not previously attainable. A discussion of fastener stress corrosion failures is presented including a review of the history and a description of the mechanism. Case histories are presented to illustrate the problems which can arise when material selection is made without proper regard for the environmental conditions. Mechanical properties and chemical compositions are included for the fasteners discussed. Several aspects of the application of high performance corrosion resistant fasteners are discussed including galvanic compatibility and torque-tension relationships.

29 CFR 1915.72 - Ladders.

Code of Federal Regulations, 2013 CFR

2013-07-01

... shipbreaking. (a) General requirements. (1) The use of ladders with broken or missing rungs or steps, broken or... 10d common wire nails or fastened with through bolts or other fasteners of equivalent strength. Cleats... nailed to each rail with five 10d common wire nails or fastened with through bolts or other fasteners of...

Derivation and test of elevated temperature thermal-stress-free fastener concept

NASA Technical Reports Server (NTRS)

Sawyer, J. W.; Blosser, M. L.; Mcwithey, R. R.

1985-01-01

Future aerospace vehicles must withstand high temperatures and be able to function over a wide temperature range. New composite materials are being developed for use in designing high-temperature lightweight structures. Due to the difference between coefficients of thermal expansion for the new composite materials and conventional high-temperature metallic fasteners, innovative joining techniques are needed to produce tight joints at all temperatures without excessive thermal stresses. A thermal-stress-free fastening technique is presented that can be used to provide structurally tight joints at all temperatures even when the fastener and joined materials have different coefficients of thermal expansion. The derivation of thermal-stress-free fasteners and joint shapes is presented for a wide variety of fastener materials and materials being joined together. Approximations to the thermal-stress-free shapes that result in joints with low-thermal-stresses and that simplify the fastener/joint shape are discussed. The low-thermal-stress fastener concept is verified by thermal and shear tests in joints using oxide-dispersion-strengthened alloy fasteners in carbon-carbon material. The test results show no evidence of thermal stress damage for temperatures up to 2000 F and the resulting joints carried shear loads at room temperature typical of those for conventional joints.

26 CFR 48.4073-2 - Exemption of tires with internal wire fastening.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Exemption of tires with internal wire fastening... internal wire fastening. The tax does not apply to sales of tires of any size or dimension manufactured from extruded tiring that is fastened or held together by means of internal wire or other metallic...

26 CFR 48.4073-2 - Exemption of tires with internal wire fastening.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 16 2011-04-01 2011-04-01 false Exemption of tires with internal wire fastening... internal wire fastening. The tax does not apply to sales of tires of any size or dimension manufactured from extruded tiring that is fastened or held together by means of internal wire or other metallic...

Development of high temperature fasteners using directionally solidified eutectic alloys

NASA Technical Reports Server (NTRS)

George, F. D.

1972-01-01

The suitability of the eutectics for high temperature fasteners was investigated. Material properties were determined as a function of temperature, and included shear parallel and perpendicular to the growth direction and torsion parallel to it. Techniques for fabricating typical fastener shapes included grinding, creep forming, and direct casting. Both lamellar Ni3Al-Ni3Nb and fibrous (Co,Cr,Al)-(Cr,Co)7C3 alloys showed promise as candidate materials for high temperature fastener applications. A brief evaluation of the performance of the best fabricated fastener design was made.

Composite fastener for use in high temperature environments

NASA Technical Reports Server (NTRS)

Miller, Robert J. (Inventor); Palusis, Mark E. (Inventor); Jarmon, David C. (Inventor)

2000-01-01

A fastener includes a composite body and a metal coupling attached to the body. The metal coupling includes an attachment structure to connect the fastener to an external structure. An assembly of components includes a first metallic component having a first coefficient of thermal expansion, a second non-metallic component having a second coefficient of thermal expansion different from the first thermal expansion and having a groove that receives a fastener that extends between the groove and the second component, the fastener slidably engaging the groove to accommodate relative expansion between the components.

Corrosion rates of fasteners in treated wood exposed to 100% relative humidity

Treesearch

Samuel L. Zelinka; Douglas R. Rammer

2009-01-01

In the past, gravimetric corrosion data for fasteners exposed to treated wood has been reported as a percent weight loss. Although percent weight loss is a valid measure of corrosion for comparing identical fasteners, it can distort the corrosion performance of fasteners with different geometries and densities. This report reevaluates a key report on the corrosiveness...

Double swivel toggle release

NASA Technical Reports Server (NTRS)

King, Guy L.; Schneider, William C.

1989-01-01

A pyrotechnic actuated structural release device is disclosed which is mechanically two fault tolerant for release. The device comprises a fastener plate and fastener body each attachable to one of a pair of structures to be joined. The fastener plate and the fastener body are fastened by a dual swivel toggle member. The toggle member is supported at one end on the fastener plate and mounted for universal pivotal movement thereon. Its other end is received in a central opening in the fastener body, and has a universally mounted retainer ring member. The toggle member is restrained by three retractable latching pins symmetrically disposed in equiangular spacing about the axis of the toggle member and positionable in latching engagement with the retainer ring member on the toggle member. Each pin is retractable by a pyrotechnic charge, the expanding gases of which are applied to a pressure receiving face on the latch pins to effect retraction from the ring member. While retraction of all three pins releases the ring member, the fastener is mechanically two fault tolerant since the failure of any single one or pair of the latch pins to retract results in an asymmetrical loading on the ring member and its dual pivotal movement ensures a release.

Welding, Bonding and Fastening, 1984

NASA Technical Reports Server (NTRS)

Buckley, J. D. (Editor); Stein, B. A. (Editor)

1985-01-01

A compilation of papers presented in a joint NASA, American Society for Metals, The George Washington University, American Welding Soceity, and Society of Manufacturing Engineers conference on Welding, Bonding, and Fastening at Langley Research Center, Hampton, VA, on October 23 to 25, 1984 is given. Papers were presented on technology developed in current research programs relevant to welding, bonding, and fastening of structural materials required in fabricating structures and mechanical systems used in the aerospace, hydrospace, and automotive industries. Topics covered in the conference included equipment, hardware and materials used when welding, brazing, and soldering, mechanical fastening, explosive welding, use of unique selected joining techniques, adhesives bonding, and nondestructive evaluation. A concept of the factory of the future was presented, followed by advanced welding techniques, automated equipment for welding, welding in a cryogenic atmosphere, blind fastening, stress corrosion resistant fasteners, fastening equipment, explosive welding of different configurations and materials, solid-state bonding, electron beam welding, new adhesives, effects of cryogenics on adhesives, and new techniques and equipment for adhesive bonding.

International concrete crosstie and fastening system survey.

DOT National Transportation Integrated Search

2013-02-01

The International Concrete Crosstie and : Fastening System Survey assesses the : international railway industrys state of practice : regarding concrete crossties and fastening : system design, performance, and research : needs. The Rail Transporta...

Topological Analyses of Symmetric Eruptive Prominences

NASA Astrophysics Data System (ADS)

Panasenco, O.; Martin, S. F.

Erupting prominences (filaments) that we have analyzed from Hα Doppler data at Helio Research and from SOHO/EIT 304 Å, show strong coherency between their chirality, the direction of the vertical and lateral motions of the top of the prominences, and the directions of twisting of their legs. These coherent properties in erupting prominences occur in two patterns of opposite helicity; they constitute a form of dynamic chirality called the ``roll effect." Viewed from the positive network side as they erupt, many symmetrically-erupting dextral prominences develop rolling motion toward the observer along with right-hand helicity in the left leg and left-hand helicity in the right leg. Many symmetricaly-erupting sinistral prominences, also viewed from the positive network field side, have the opposite pattern: rolling motion at the top away from the observer, left-hand helical twist in the left leg, and right-hand twist in the right leg. We have analysed the motions seen in the famous movie of the ``Grand Daddy" erupting prominence and found that it has all the motions that define the roll effect. From our analyses of this and other symmetric erupting prominences, we show that the roll effect is an alternative to the popular hypothetical configuration of an eruptive prominence as a twisted flux rope or flux tube. Instead we find that a simple flat ribbon can be bent such that it reproduces nearly all of the observed forms. The flat ribbon is the most logical beginning topology because observed prominence spines already have this topology prior to eruption and an initial long magnetic ribbon with parallel, non-twisted threads, as a basic form, can be bent into many more and different geometrical forms than a flux rope.

The Alcoa ram fastener: A reusable blind rivet

NASA Technical Reports Server (NTRS)

Dewalt, W. J.

1972-01-01

Results of tensile, shear, fatigue and accelerated weathering tests are presented for the ram fastener, a reusable, single unit blind rivet. The effects of variations in hole size, grip length and sheet thickness on strength properties of the fastener were determined. The test results show these fasteners to have strength characteristics suitable for light structural applications. Exposure to accelerated weathering did not impair their performance.

International concrete crosstie and fastening system survey.

DOT National Transportation Integrated Search

2013-02-01

The International Concrete Crosstie and Fastening System Survey assesses the international railway industrys state of practice regarding concrete crossties and fastening system design, performance, and research needs. The Rail Transportation and E...

21 CFR 882.5360 - Cranioplasty plate fastener.

Code of Federal Regulations, 2011 CFR

2011-04-01

... fastener. (a) Identification. A cranioplasty plate fastener is a screw, wire, or other article made of tantalum, vitallium, or stainless steel used to secure a plate to the patient's skull to repair a skull...

21 CFR 882.5360 - Cranioplasty plate fastener.

Code of Federal Regulations, 2010 CFR

2010-04-01

... fastener. (a) Identification. A cranioplasty plate fastener is a screw, wire, or other article made of tantalum, vitallium, or stainless steel used to secure a plate to the patient's skull to repair a skull...

Spline-Locking Screw Fastening Strategy (SLSFS)

NASA Technical Reports Server (NTRS)

Vranish, John M.

1991-01-01

A fastener was developed by NASA Goddard for efficiently performing assembly, maintenance, and equipment replacement functions in space using either robotic or astronaut means. This fastener, the 'Spline Locking Screw' (SLS) would also have significant commercial value in advanced manufacturing. Commercial (or DoD) products could be manufactured in such a way that their prime subassemblies would be assembled using SLS fasteners. This would permit machines and robots to disconnect and replace these modules/parts with ease, greatly reducing life cycle costs of the products and greatly enhancing the quality, timeliness, and consistency of repairs, upgrades, and remanufacturing. The operation of the basic SLS fastener is detailed, including hardware and test results. Its extension into a comprehensive fastening strategy for NASA use in space is also outlined. Following this, the discussion turns toward potential commercial and government applications and the potential market significance of same.

Spline-locking screw fastening strategy

NASA Technical Reports Server (NTRS)

Vranish, John M.

1992-01-01

A fastener was developed by NASA Goddard for efficiently performing assembly, maintenance, and equipment replacement functions in space using either robotics or astronaut means. This fastener, the 'Spline Locking Screw' (SLS) would also have significant commercial value in advanced space manufacturing. Commercial (or DoD) products could be manufactured in such a way that their prime subassemblies would be assembled using SLS fasteners. This would permit machines and robots to disconnect and replace these modules/parts with ease, greatly reducing life cycle costs of the products and greatly enhancing the quality, timeliness, and consistency of repairs, upgrades, and remanufacturing. The operation of the basic SLS fastener is detailed, including hardware and test results. Its extension into a comprehensive fastening strategy for NASA use in space is also outlined. Following this, the discussion turns toward potential commercial and government applications and the potential market significance of same.

Online Condition Monitoring of a Rail Fastening System on High-Speed Railways Based on Wavelet Packet Analysis

PubMed Central

Wei, Jiahong; Liu, Chong; Ren, Tongqun; Liu, Haixia; Zhou, Wenjing

2017-01-01

The rail fastening system is an important part of a high-speed railway track. It is always critical to the operational safety and comfort of railway vehicles. Therefore, the condition detection of the rail fastening system, looseness or absence, is an important task in railway maintenance. However, the vision-based method cannot identify the severity of rail fastener looseness. In this paper, the condition of rail fastening system is monitored based on an automatic and remote-sensing measurement system. Meanwhile, wavelet packet analysis is used to analyze the acceleration signals, based on which two damage indices are developed to locate the damage position and evaluate the severity of rail fasteners looseness, respectively. To verify the effectiveness of the proposed method, an experiment is performed on a high-speed railway experimental platform. The experimental results show that the proposed method is effective to assess the condition of the rail fastening system. The monitoring system significantly reduces the inspection time and increases the efficiency of maintenance management. PMID:28208732

Easy insert, easy release toggle bolt fastener

NASA Technical Reports Server (NTRS)

Kubokawa, C. C.

1970-01-01

Releasable pin-type toggle bolt fastener is constructed so that, when positioned in hole, toggle action prevents its removal and locknut anchors it firmly in place. Fastener is easily removed by loosening locknut and retraction of toggle wings.

Concrete crosstie fastener sub-system testing and modeling.

DOT National Transportation Integrated Search

2014-02-10

The primary objective of this project is to identify methods of improving concrete railroad crosstie fastening system design and performance by conducting a thorough investigation of the behavior of the fastening system using Finite Element Analysis ...

Current and Future Applications of Mechanical Fasteners for Light-Frame Wood Structures: Proceedings of Mechanical Fasteners Plenary Session at the Forest Products Research Society Annual Meeting

Treesearch

Leslie H. Groom; [Compiler

1993-01-01

The title of this publication-"Current and Future Applications of Mechanical Fasteners for Light-Frame Wood Structures" is the theme of this plenary session from the 1991 annual meeting of the Forest Products Research Society (FPRS). This theme was chosen to address current issues in the forest products industry: changing design codes, fastener performance,...

"Easy-on, Easy-off" Blanket Fastener

NASA Technical Reports Server (NTRS)

Kolecki, Ronald E.; Clatterbuck, Carroll H.

1992-01-01

Fasteners hold flexible blanket on set of posts on supporting structure. Disk of silicone rubber cast on disk of Mylar, fastened to blanket and press-fit over post to nest securely in groove. No tools needed for installation or removal.

Discrimination between Fatigue Cracking and Mechanical Damage in Aircraft Fastener Holes by Eddy-Current Phase Rotation

DTIC Science & Technology

2016-08-01

present work, a systematic BHEC and fractographic study has been conducted by inspecting several hundred fastener holes in ex-service F/A- 18 ...BHEC and fractographic study was conducted by inspecting several hundred fastener holes in ex-service F/A- 18 aircraft bulkheads, following fatigue...study is based on BHEC inspections of several hundred fastener holes in ex-service F/A- 18 aircraft bulkheads. These Al-alloy bulkheads contained

Development of Anti-Loosening Performance of Hyper Lock Nut

NASA Astrophysics Data System (ADS)

Nishiyama, Shuji; Migita, Hiroaki; Kataoka, Mitumasa; Nakasaki, Nobuyuki; Murano, Kohshi

Bolted joints are widely used in mechanical structures as they allow easy disassembly for maintenance without high cost. However, vibration-induced loosening due to dynamic loading remains a long-unresolved issue. We have developed a new type of nut named the hyper lock nut (HLN) that offers anti-loosening performance without a complicated tightening process and tools. In this study, we investigated the mechanisms of joints bolted with the HLN, and tightening behavior was analyzed using the three-dimensional finite element method. The analytical results were compared with the experimental results for the HLN, and close qualitative agreement was observed between the two with respect to displacement, tightening force and tightening torque. We found a number of new aspects and plus points for joints bolted with the HLN in comparison to those fastened with JIS standard nuts. It was found that the tightening torque of the HLN is higher than that of JIS standard nuts, and that satisfactory anti-loosening performance can be realized through the thread contact force at the slit region and the angular face of the bearing surface.

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

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Bush, Harold G.

2001-01-01

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

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

NASA Technical Reports Server (NTRS)

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

2001-01-01

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

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

NASA Astrophysics Data System (ADS)

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

2001-01-01

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

Quick-Change Anode for Plating

NASA Technical Reports Server (NTRS)

Beasley, J. L.

1987-01-01

Proposed fastener for attaching electroplating anode improves quality of plating and increases productivity. Notches in twist-lock fastener mates with projections on end of anode bar. Fastener made of titanium for compatibility with copper-plating solution. Also constructed in snap-on, snap-off configuration.

Samus Counter Lifting Fixture

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

Stredde, H.; /Fermilab

1998-05-27

A lifting fixture has been designed to handle the Samus counters. These counters are being removed from the D-zero area and will be transported off site for further use at another facility. This fixture is designed specifically for this particular application and will be transferred along with the counters. The future use of these counters may entail installation at a facility without access to a crane and therefore a lift fixture suitable for both crane and/or fork lift usage has been created The counters weigh approximately 3000 lbs. and have threaded rods extended through the counter at the top comersmore » for lifting. When these counters were first handled/installed these rods were used in conjunction with appropriate slings and handled by crane. The rods are secured with nuts tightened against the face of the counter. The rod thread is M16 x 2({approx}.625-inch dia.) and extends 2-inch (on average) from the face of the counter. It is this cantilevered rod that the lift fixture engages with 'C' style plates at the four top comers. The strongback portion of the lift fixture is a steel rectangular tube 8-inch (vertical) x 4-inch x .25-inch wall, 130-inch long. 1.5-inch square bars are welded perpendicular to the long axis of the rectangular tube at the appropriate lift points and the 'C' plates are fastened to these bars with 3/4-10 high strength bolts -grade 8. Two short channel sections are positioned-welded-to the bottom of the rectangular tube on 40 feet centers, which are used as locators for fork lift tines. On the top are lifting eyes for sling/crane usage and are rated at 3500 lbs. safe working load each - vertical lift only.« less

Experimental analysis of thread movement in bolted connections due to vibrations

NASA Technical Reports Server (NTRS)

Ramey, G. ED; Jenkins, Robert C.

1994-01-01

The objective of this study was to identify the main design parameters contributing to loosening of bolts due to vibration and to identify their relative importance and degree of contribution to bolt loosening. Vibration testing was conducted on a shaketable with a controlled-random input in the dynamic testing laboratory of the Structural Test Division of MSFC. Test specimens which contained one test bolt were vibrated for a fixed amount of time and percentage of pre-load loss was measured. Each specimen tested implemented some combination of eleven design parameters as dictated by the design of experiment methodology employed. The eleven design parameters were: bolt size (diameter), lubrication on bolt, hole tolerance, initial pre-load, nut locking device, grip length, thread pitch, lubrication between mating materials, class of fit, joint configuration and mass of configuration. These parameters were chosen for this experiment because they are believed to be the design parameters having the greatest impact on bolt loosening. Two values of each design parameter were used and each combination of parameters tested was subjected to two different directions of vibration and two different g-levels of vibration. One replication was made for each test to gain some indication of experimental error and repeatability and to give some degree of statistical credibility to the data, resulting in a total of 96 tests being performed. The results of the investigation indicated that nut locking devices, joint configuration, fastener size, and mass of configuration were significant in bolt loosening due to vibration. The results of this test can be utilized to further research the complex problem of bolt loosening due to vibration.

40 CFR 420.121 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... operations. (e) The term strip, sheet, and miscellaneous products means steel products other than wire products and fasteners. (f) The term wire products and fasteners means steel wire, products manufactured from steel wire, and steel fasteners manufactured from steel wire or other steel shapes. ...

40 CFR 420.121 - Specialized definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... operations. (e) The term strip, sheet, and miscellaneous products means steel products other than wire products and fasteners. (f) The term wire products and fasteners means steel wire, products manufactured from steel wire, and steel fasteners manufactured from steel wire or other steel shapes. ...

14 CFR 27.607 - Fasteners.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fasteners. 27.607 Section 27.607 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... bolt, screw, nut, pin, or other fastener whose loss could jeopardize the safe operation of the...

14 CFR 23.607 - Fasteners.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fasteners. 23.607 Section 23.607 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... would preclude continued safe flight and landing. (b) Fasteners and their locking devices must not be...

14 CFR 23.607 - Fasteners.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fasteners. 23.607 Section 23.607 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... would preclude continued safe flight and landing. (b) Fasteners and their locking devices must not be...

14 CFR 27.607 - Fasteners.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fasteners. 27.607 Section 27.607 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... bolt, screw, nut, pin, or other fastener whose loss could jeopardize the safe operation of the...

The Effect of Fatigue Cracks on Fastener Flexibility, Load Distribution and Fatigue Crack Growth

DTIC Science & Technology

2012-05-01

fastener will transfer within a given fastener pattern. iv iv However, current methods do not account for the change in flexibility at a fastener...affects the growth of the crack. Thus, as the effect of the crack starts to impact the load transfer of the joint there is a need to account for...not account for spectrum loading but typically were cycled from 1g to limit or maximum flight load and then correlated to measured usage using

15 CFR 280.201 - Violations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... order issued thereunder. (b) Sale of fasteners. It shall be unlawful for a manufacturer or distributor, in conjunction with the sale or offer for sale of fasteners from a single lot, to knowingly..., characteristics, properties, mechanical or performance marks, chemistry, or strength of the lot of fasteners; or...

15 CFR 280.201 - Violations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... order issued thereunder. (b) Sale of fasteners. It shall be unlawful for a manufacturer or distributor, in conjunction with the sale or offer for sale of fasteners from a single lot, to knowingly..., characteristics, properties, mechanical or performance marks, chemistry, or strength of the lot of fasteners; or...

78 FR 66989 - Designation of Six Individuals and Four Entities Pursuant to Executive Order 13581, “Blocking...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-07

... 86483143 (Russia); Public Registration Number 1087746669845 (Russia) [TCO]. 2. FASTEN TOURISM LLC (a.k.a. FASTEN TOURISM DUBAI; a.k.a. FASTEN TOURS LLC), P.O. Box 19583, Dubai, United Arab Emirates; 171 Omar Ibn...

Lock-pin and collar fastening system : final report.

DOT National Transportation Integrated Search

1997-02-01

In 1993, a steel girder I-beam deck was extended to cross a new on-ramp at the Marquam Bridge Interchange in Portland, Oregon. The steel members of this new structure were fastened together using the lock-pin and collar fastening system. : These fast...

Reusable captive blind fastener

NASA Technical Reports Server (NTRS)

Peterson, S. A. (Inventor)

1981-01-01

A one piece reusable fastener capable of joining materials together from one side (blind backside) comprises a screw driven pin ending in a wedge-shaped expander cone. The cone cooperates within a slotted collar end which has a number of tangs on a cylindrical body. The fastener is set by inserting it through aligned holes in the workpieces to be joined. Turning the pin in one direction draws the cone into the collar, deforming the tangs radially outward to mate with tapered back-tapered hold in the workpiece, thus fastening the two pieces together. Reversing the direction of the pin withdraws the cone from the collar, and allows the tangs to resume their contracted configuration without withdrawing the fastener from the insertion hole. The fastener is capable of joining materials together from only one side with substantial strength in tension and shear over many resue attachment cycles, with no special operations on the main assembly parts other than the tapering of the back end of the insertion hole.

78 FR 46536 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-01

... eddy current inspection of the fastener holes for defects and repair if necessary. We are proposing... also includes doing a high frequency eddy current inspection of the fastener holes for defects and... frequency eddy current inspection of the fastener holes for defects and all applicable repairs, in...

A structural health monitoring fastener for tracking fatigue crack growth in bolted metallic joints

NASA Astrophysics Data System (ADS)

Rakow, Alexi Schroder

Fatigue cracks initiating at fastener hole locations in metallic components are among the most common form of airframe damage. The fastener hole site has been surveyed as the second leading initiation site for fatigue related accidents of fixed wing aircraft. Current methods for inspecting airframes for these cracks are manual, whereby inspectors rely on non-destructive inspection equipment or hand-held probes to scan over areas of a structure. Use of this equipment often demands disassembly of the vehicle to search appropriate hole locations for cracks, which elevates the complexity and cost of these maintenance inspections. Improved reliability, safety, and reduced cost of such maintenance can be realized by the permanent integration of sensors with a structure to detect this damage. Such an integrated system of sensors would form a structural health monitoring (SHM) system. In this study, an Additive, Interleaved, Multi-layer Electromagnetic (AIME) sensor was developed and integrated with the shank of a fastener to form a SHM Fastener, a new SHM technology targeted at detection of fastener hole cracks. The major advantages of the SHM Fastener are its installation, which does not require joint layer disassembly, its capability to detect inner layer cracks, and its capability to operate in a continuous autonomous mode. Two methods for fabricating the proposed SHM Fastener were studied. The first option consisted of a thin flexible printed circuit film that was bonded around a thin metallic sleeve placed around the fastener shank. The second option consisted of coating sensor materials directly to the shank of a part in an effort to increase the durability of the sensor under severe loading conditions. Both analytical and numerical models were developed to characterize the capability of the sensors and provide a design tool for the sensor layout. A diagnostic technique for crack growth monitoring was developed to complete the SHM system, which consists of the sensor, data acquisition hardware, algorithm, and diagnostic display. The AIME sensor design, SHM Fastener, and complete SHM system are presented along with experimental results from a series of single-layer and bolted double lap joint aluminum laboratory specimens to validate the capability of these sensors to monitor metallic joints for fastener hole cracks. Fatigue cracks were successfully tracked to over 0.7 inches from the fastener hole in these tests. Sensor output obtained from single-layer fatigue specimens was compared with analytical predictions for fatigue crack growth versus cycle number showing a good correlation in trend between sensor output and predicted crack size.

Antibacterial Surgical Silk Sutures Using a High-Performance Slow-Release Carrier Coating System.

PubMed

Chen, Xiaojie; Hou, Dandan; Wang, Lu; Zhang, Qian; Zou, Jiahan; Sun, Gang

2015-10-14

Sutures are a vital part for surgical operation, and suture-associated surgical site infections are an important issue of postoperative care. Antibacterial sutures have been proved to reduce challenging complications caused by bacterial infections. In recent decades, triclosan-free sutures have been on their way to commercialization. Alternative antibacterial substances are becoming relevant to processing surgical suture materials. Most of the antibacterial substances are loaded directly on sutures by dipping or coating methods. The aim of this study was to optimize novel antibacterial braided silk sutures based on levofloxacin hydrochloride and poly(ε-caprolactone) by two different processing sequences, to achieve suture materials with slow-release antibacterial efficacy and ideal physical and handling properties. Silk strands were processed into sutures on a circular braiding machine, and antibacterial treatment was introduced alternatively before or after braiding by two-dipping-two-rolling method (M1 group and M2 group). The antibacterial activity and durability against Staphylococcus aureus and Escherichia coli were tested. Drug release profiles were measured in phosphate buffer with different pH values, and release kinetics model was built to analyze the sustained drug release mechanism between the interface of biomaterials and the in vitro aqueous environment. Knot-pull tensile strength, thread-to-thread friction, and bending stiffness were determined to evaluate physical and handling properties of sutures. All coated sutures showed continuous antibacterial efficacy and slow drug release features for more than 5 days. Besides, treated sutures fulfilled U.S. Pharmacopoeia required knot-pull tensile strength. The thread-to-thread friction and bending stiffness for the M1 group changed slightly when compared with those of uncoated ones. However, physical and handling characteristics of the M2 group tend to approach those of monofilament ones. The novel suture showed acceptable in vitro cytotoxicity according to ISO 10993-5. Generally speaking, all coated sutures show potential in acting as antibacterial suture materials, and M1 group is proved to have a higher prospect for clinical applications.

76 FR 38062 - Airworthiness Directives; Gulfstream Aerospace LP Model Galaxy and Gulfstream 200 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-29

... with certified mechanical properties of this fastener can potentially lead to an unsafe condition. The... certified mechanical properties of this fastener can potentially lead to an unsafe condition. The unsafe...-conformity with certified mechanical properties of this fastener can potentially lead to an unsafe condition...

49 CFR 231.17 - Specifications common to all steam locomotives.

Code of Federal Regulations, 2011 CFR

2011-10-01

... shall be securely fastened with bolts, rivets, or studs. (ii) Locomotives having Wootten type boilers... inches above outside edge of running boards, securely fastened with bolts, rivets, or studs. (c... inches in height, measured from the top of end sill, and securely fastened with bolts or rivets. (f...

Statistics of Crack Growth in Engine Materials. Volume 2. Spectrum Loading and advanced Techniques

DTIC Science & Technology

1984-02-01

Histories of Some WPB Fastener H oles ..................................................................................... 66 51 Typical Sample Function of...Computed Directly from Some Actual Time- Histories of W PB Fastener Holes ................................................................ 77 56 Simulated...Sample Functions of Crack Propagation Time- Histories for W PB Fastener Holes ................................................................ 78 57

14 CFR 125.211 - Seat and safety belts.

Code of Federal Regulations, 2014 CFR

2014-01-01

... emergency exit. (f) Each occupant of a seat equipped with a shoulder harness must fasten the shoulder harness during takeoff and landing, except that, in the case of crewmembers, the shoulder harness need not be fastened if the crewmember cannot perform his required duties with the shoulder harness fastened...

Intelligent Fasteners

NASA Technical Reports Server (NTRS)

1997-01-01

Under a Small Business Innovation Research contract from Marshall Space Flight Center, Ultrafast, Inc. developed the world's first, high-temperature resistant, "intelligent" fastener. NASA needed a critical-fastening appraisal and validation of spacecraft segments that are coupled together in space. The intelligent-bolt technology deletes the self-defeating procedure of having to untighten the fastener, and thus upset the joint, during inspection and maintenance. The Ultrafast solution yielded an innovation that is likely to revolutionize manufacturing assembly, particularly the automobile industry. Other areas of application range from aircraft, computers and fork-lifts to offshore platforms, buildings, and bridges.

Inspection of aircraft fastener holes using a conically shaped multi-element phased array probe

NASA Astrophysics Data System (ADS)

Selman, J. J.; Miller, J. T.; Moles, M. D. C.; Dupuis, O.; Herzog, P. G.

2002-05-01

A novel inspection technique is described using phased ultrasonic arrays to detect faying surface cracks in the first layer around the base of a fastener hole with fasteners installed. A unique phased array probe incorporates a matrix of ultrasonic elements arranged in a conical configuration encircling the fastener head. This arrangement permits deflection of the ultrasonic beam in three dimensions, and adapts to different hole diameters and skin thickness. Full circumferential scans are performed using a pre-programmed sequence of phased array focal laws. The inspection method uses pulse-echo at a variety of angles incident on the crack to thoroughly cover the fastener hole and surrounding area, and is designed to detect cracks as small as 0.030″ in length.

Simplified Design Method for Tension Fasteners

NASA Astrophysics Data System (ADS)

Olmstead, Jim; Barker, Paul; Vandersluis, Jonathan

2012-07-01

Tension fastened joints design has traditionally been an iterative tradeoff between separation and strength requirements. This paper presents equations for the maximum external load that a fastened joint can support and the optimal preload to achieve this load. The equations, based on linear joint theory, account for separation and strength safety factors and variations in joint geometry, materials, preload, load-plane factor and thermal loading. The strength-normalized versions of the equations are applicable to any fastener and can be plotted to create a "Fastener Design Space", FDS. Any combination of preload and tension that falls within the FDS represents a safe joint design. The equation for the FDS apex represents the optimal preload and load capacity of a set of joints. The method can be used for preliminary design or to evaluate multiple pre-existing joints.

Detailed finite element analysis and preliminary study of the effects of friction and fastener pre-tension on the mechanical behavior of fastened built-up members

NASA Astrophysics Data System (ADS)

Bonachera Martin, Francisco Javier

The characterization of fatigue resistance is one of the main concerns in structural engineering, a concern that is particularly important in the evaluation of existing bridge members designed or erected before the development of fatigue design provisions. The ability of a structural member to develop alternate load paths after the failure of a component is known as member-level or internal redundancy. In fastened built-up members, these alternate load paths are affected by the combination of fastener pre-tension and friction between the structural member components in contact. In this study, a finite element methodology to model and analyze riveted and bolted built-up members was developed in ABAQUS and validated with experimental results. This methodology was used to created finite element models of three fastened plates subjected to tension, in which the middle plate had failed, in order to investigate the fundamental effects of combined fastener pre-tension and friction on their mechanical behavior. Detailed finite element models of riveted and bolted built-up flexural members were created and analyze to understand the effect of fastener pre-tension in member-level redundancy and resistance to fatigue and fracture. The obtained results showed that bolted members are able to re-distribute a larger portion of the load away from the failing component into the rest of the member than riveted members, and that this transfer of load also took place over a smaller length. Superior pre-tension of bolts, in comparison to rivets, results in larger frictional forces that develop at the contact interfaces between components and constitute additional alternate load paths that increase member-level redundancy which increase the fatigue and fracture resistance of the structural member during the failure of one of its components. Although fatigue and fracture potential may be mitigated by compressive stresses developing around the fastener hole due to fastener pre-tension, it was also observed, that at the surface of the fastener hole and at the contact interface with another plate, tensional stresses could develop; however, further computational and experimental work should be performed to verify this claim.

Wood : mechanical fasteners

Treesearch

Douglas R. Rammer

2001-01-01

The strength and stability of any structure depends heavily on the fasteners that hold its parts together. One prime advantage of wood as a structural material is the ease with which wood structural parts can be joined together using a wide variety of fasteners: nails, staples, screws, lag screws, bolts, and various types of metal connectors. For the utmost rigidity,...

14 CFR 137.42 - Fastening of safety belts and shoulder harnesses.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Fastening of safety belts and shoulder... AGRICULTURAL AIRCRAFT OPERATIONS Operating Rules § 137.42 Fastening of safety belts and shoulder harnesses. No... belt and shoulder harness properly secured about that person except that the shoulder harness need not...

14 CFR 137.42 - Fastening of safety belts and shoulder harnesses.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Fastening of safety belts and shoulder... AGRICULTURAL AIRCRAFT OPERATIONS Operating Rules § 137.42 Fastening of safety belts and shoulder harnesses. No... belt and shoulder harness properly secured about that person except that the shoulder harness need not...

14 CFR 137.42 - Fastening of safety belts and shoulder harnesses.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Fastening of safety belts and shoulder... AGRICULTURAL AIRCRAFT OPERATIONS Operating Rules § 137.42 Fastening of safety belts and shoulder harnesses. No... belt and shoulder harness properly secured about that person except that the shoulder harness need not...

14 CFR 137.42 - Fastening of safety belts and shoulder harnesses.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fastening of safety belts and shoulder... AGRICULTURAL AIRCRAFT OPERATIONS Operating Rules § 137.42 Fastening of safety belts and shoulder harnesses. No... belt and shoulder harness properly secured about that person except that the shoulder harness need not...

14 CFR 137.42 - Fastening of safety belts and shoulder harnesses.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Fastening of safety belts and shoulder... AGRICULTURAL AIRCRAFT OPERATIONS Operating Rules § 137.42 Fastening of safety belts and shoulder harnesses. No... belt and shoulder harness properly secured about that person except that the shoulder harness need not...

Advances in transient (pulsed) eddy current for inspection of multi-layer aluminum structures in the presence of ferrous fasteners

NASA Astrophysics Data System (ADS)

Desjardins, D. R.; Vallières, G.; Whalen, P. P.; Krause, T. W.

2012-05-01

An experimental investigation of the electromagnetic processes underlying transient (pulsed) eddy current inspection of aircraft wing structures in the vicinity of ferrous fasteners is performed. The separate effects of transient excitation of ferrous fastener and eddy currents induced in the surrounding aluminum structure are explored using a transmit-receive configuration with transient excitation of a steel rod, an aluminum plate with a bore hole and a steel rod through the bore hole. Observations are used to interpret results from a coupled driving and differential coil sensing unit applied to detect fatigue cracks emanating from bolt holes in aluminum structures with ferrous fasteners present. In particular, it is noted that abrupt magnetization of the fastener, by the probe's central driving unit, can transfer flux and consequently, induce strong eddy current responses deep within the aluminum structure in the vicinity of the bore hole. Rotation of the probe, centered over the fastener, permits detection of subsurface discontinuities, such as cracks, by the pair of differentially connected pickup coils.

Joining technologies for the 1990s: Welding, brazing, soldering, mechanical, explosive, solid-state, adhesive

NASA Technical Reports Server (NTRS)

Buckley, John D. (Editor); Stein, Bland A. (Editor)

1986-01-01

A compilation of papers presented in a joint NASA, American Society for Metals, The George Washington University, American Welding Society, and Society of Manufacturing Engineers Conference on Welding, Bonding, and Fastening at Langley Research Center, Hampton, VA, on October 23 to 25, 1984 is given. Papers were presented on technology developed in current research programs relevant to welding, bonding, and fastening of structural materials required in fabricating structures and mechanical systems used in the aerospace, hydrospace, and automotive industries. Topics covered in the conference included equipment, hardware and materials used when welding, brazing, and soldering, mechanical fastening, explosive welding, use of unique selected joining techniques, adhesives bonding, and nondestructive evaluation. A concept of the factory of the future was presented, followed by advanced welding techniques, automated equipment for welding, welding in a cryogenic atmosphere, blind fastening, stress corrosion resistant fasteners, fastening equipment, explosive welding of different configurations and materials, solid-state bonding, electron beam welding, new adhesives, effects of cryogenics on adhesives, and new techniques and equipment for adhesive bonding.

Basic space payload fastener

NASA Technical Reports Server (NTRS)

Vranish, J. M.; Gorevan, Stephen

1995-01-01

A new basic space fastener has been developed and tested by the GSFC. The purposes of this fastener are to permit assembly and servicing in space by astronauts and/or robots and to facilitate qualification of payloads on Earth prior to launch by saving time and money during the systems integration and component testing and qualification processes. The space fastener is a rework of the basic machine screw such that crossthreading is impossible; it is self-locking and will not work its way out during launch (vibration proof); it will not wear out despite repeated use; it occupies a small foot print which is comparable to its machine screw equivalent, and it provides force and exhibits strength comparable to its machine screw equivalent. Construction is ultra-simple and cost effective and the principle is applicable across the full range of screw sizes ranging from a #10 screw to 2.5 cm (1 in) or more. In this paper, the fastener principles of operation will be discussed along with test results and construction details. The new fastener also has considerable potential in the commercial sector. A few promising applications will be presented.

Fastener Corrosion: A Result of Moisture Problems in the Building Envelope

Treesearch

Samuel L. Zelinka

2013-01-01

This paper reviews recent literature on the corrosion of metals embedded in wood and highlights the link be-tween moisture accumulation in wood and fastener cor-rosion. Mechanisms of fastener corrosion are described including dependence upon wood moisture content. These fundamental concepts are applied to practical examples by explaining how hygrothermal models can be...

Angle to grain strength of dowel-type fasteners

Treesearch

Lawrence A. Soltis; Suparman Karnasudirdja; James K. Little

1987-01-01

Timber structures require adequate connections between components. Connection design is based on the performance criterion of a single fastener. This study is part of a research effort by the Forest Products Laboratory to establish a common basis design criteria for lateral strength of dowel-type fasteners that includes nails, screws, lag screws, and bolts. A general...

19 CFR 24.13a - Car, compartment, and package seals; and fastenings; standards; acceptance by Customs.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 1 2011-04-01 2011-04-01 false Car, compartment, and package seals; and... PROCEDURE § 24.13a Car, compartment, and package seals; and fastenings; standards; acceptance by Customs. (a) General standards. The seals and fastenings, together, shall (1) Be strong and durable; (2) Be capable of...

Fastenings

Treesearch

Lawrence A. Soltis

1999-01-01

The strength and stability of any structure depend heavily on the fastenings that hold its parts together. One prime advantage of wood as a structural material is the ease with which wood structural parts can be joined together with a wide variety of fastenings— nails, spikes, screws, bolts, lag screws, drift pins, staples, and metal connectors of various types. For...

Fastenings

Treesearch

Douglas R. Rammer

2010-01-01

The strength and stability of any structure depend heavily on the fastenings that hold its parts together. One prime advantage of wood as a structural material is the ease with which wood structural parts can be joined together with a wide variety of fastenings—nails, spikes, screws, bolts, lag screws, drift pins, staples, and metal connectors of various types. For...

75 FR 66653 - Airworthiness Directives; McDonnell Douglas Corporation Model MD-90-30 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-29

... the left and right engine aft mounts with new fasteners, in accordance with the Accomplishment... defects of the upper fasteners of the aft mount support fittings of the left and right engines, and corrective actions if necessary. This new AD requires repetitive replacement of the upper row of fasteners of...

Electromagnetic Detection of Fatigue Cracks under Protruding Head Ferromagnetic Fasteners

NASA Technical Reports Server (NTRS)

Wincheski, Buzz; Namkung, Min

2004-01-01

The detection of fatigue cracks under installed fasteners has been a major goal of the aging aircraft NDE community. The Sliding Probe, Magneto-Optic Imager, Rotating Self-Nulling Probe, Low Frequency Eddy Current Array, and Eddyscan systems are among the instruments developed for this inspection. It has been verified that the detection of fatigue cracks under flush head aluminum and titanium fasteners can be accomplished with a high resolution by the above techniques. The detection of fatigue cracks under ferromagnetic and protruding head fasteners, however, has been found to be much more difficult. For the present work, the inspection for fatigue cracks under SAE 4340 Steel Hi-Lok fasteners is explored. Modifications to the Rotating Self-Nulling Eddy Current Probe System are presented which enable the detection of fatigue cracks hidden under the protruding head of the ferromagnetic fastener. Inspection results for samples with varying length EDM notches are shown, as well as a comparison between the signature from an EDM notch and an actual fatigue crack. Finite Element Modeling is used to investigate the effect of the ferromagnetic fastener on the induced eddy current distribution in order to help explain the detection characteristics of the system. This paper will also introduce a modification to the Rotating Probe System designed specifically for the detection of deeply buried flaws in multilayer conductors. The design change incorporates a giant magnetoresistive (GMR) sensor as the pickup device to improve the low frequency performance of the probe. The flaw detection capabilities of the GMR based Self- Nulling Probe are presented along with the status of the GMR based Rotating Probe System for detection of deeply buried flaws under installed fasteners.

Pressurized fluid torque driver control and method

NASA Technical Reports Server (NTRS)

Cook, Joseph S., Jr. (Inventor)

1994-01-01

Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

Displaceable Gear Torque Controlled Driver

NASA Technical Reports Server (NTRS)

Cook, Joseph S., Jr. (Inventor)

1997-01-01

Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

Electrochemical corrosion testing of fasteners in extracts of treated wood

Treesearch

Samuel L. Zelinka; Douglas R. Rammer; Donald S. Stone

2008-01-01

A recent change in wood preservatives has highlighted the need for a rapid, quantitative test to measure the corrosion rates of metals in contact with treated wood that could be used to evaluate new fasteners or new wood preservatives. A new method was developed where polarisation resistance tests were conducted on fasteners exposed to a water extract of wood treated...

Fabrication technology: A compilation

NASA Technical Reports Server (NTRS)

1974-01-01

A compilation is presented which supplies technical information on the assembly of diverse components into functional assemblies and subassemblies, as well as information on several fasteners and fastening techniques that join components, subassemblies, and complete assemblies to achieve a functional unit. Quick-disconnect fasteners are described, along with several devices and methods for attaching thermal insulators, and for joining and separating objects in the absence of gravity.

Combining hygrothermal and corrosion models to predict corrosion of metal fasteners embedded in wood

Treesearch

Samuel L. Zelinka; Dominique Derome; Samuel V. Glass

2011-01-01

A combined heat, moisture, and corrosion model is presented and used to simulate the corrosion of metal fasteners embedded in solid wood exposed to the exterior environment. First, the moisture content and temperature at the wood/fastener interface is determined at each time step. Then, the amount of corrosion is determined spatially using an empirical corrosion rate...

75 FR 38056 - Airworthiness Directives; McDonnell Douglas Corporation Model MD-90-30 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-01

... (Row A) of the support fittings of the left and right engine aft mount with new fasteners. The service... fasteners (Row A) of the support fittings of the left and right engine aft mounts with new fasteners, in... fittings of the left and right engines, and corrective actions if necessary. This proposed AD would instead...

Development of an advanced high-temperature fastener system for advanced aerospace vehicle application

NASA Technical Reports Server (NTRS)

Kull, F. R.

1975-01-01

The results of a program to develop a lightweight high temperature reusable fastening system for aerospace vehicle thermal protection system applications are documented. This feasibility program resulted in several fastener innovations which will meet the specific needs of the heat shield application. Three systems were designed from Hayes 188 alloy and tested by environmental exposure and residual mechanical properties. The designs include a clinch stud with a collar retainer, a weld stud with a split ring retainer, and a caged stud with a collar retainer. The results indicated that a lightweight, reusable, high temperature fastening system can be developed for aerospace vehicle application.

Detection and imaging of corrosion around wing skin fasteners using the dripless bubbler ultrasonic scanner

NASA Astrophysics Data System (ADS)

Hsu, David K.; Barnard, Daniel J.

1998-03-01

The galvanic action between steel fasteners and aluminum wing skins of aircraft often leads to hidden exfoliation corrosion around the countersink surface of the fastener heads. To detect and evaluate the severity of such corrosion defects, the Dripless Bubbler ultrasonic scanner was applied. This technique uses a focused beam of high frequency ultrasound in a closed-cycle, water-coupled scan of wing skin test panels containing corroded and uncorroded fasteners. With full waveform acquisition, not only the lateral extent but also the depth profile of the corrosions around the fastener heads were mapped out, subject to shadowing of defects at different depth. The technique is capable of providing quantitative assessment of the severity of the corrosion. In tests conducted to evaluate different techniques, the Dripless Bubbler has shown high probability of detection and low false call rate. The presence of paint on the surface did not degrade the performance of the technique. In addition, the Dripless Bubbler was also used on wing skin panels containing repair 'blend-out' regions that had 0.020' to 0.100' of metal removed from the surface by grinding. Corrosions around fasteners in the blend-out regions were also detected.

Thermal stress in high temperature cylindrical fasteners

NASA Technical Reports Server (NTRS)

Blosser, Max L.

1988-01-01

Uninsulated structures fabricated from carbon or silicon-based materials, which are allowed to become hot during flight, are attractive for the design of some components of hypersonic vehicles. They have the potential to reduce weight and increase vehicle efficiency. Because of manufacturing contraints, these structures will consist of parts which must be fastened together. The thermal expansion mismatch between conventional metal fasteners and carbon or silicon-based structural materials may make it difficult to design a structural joint which is tight over the operational temperature range without exceeding allowable stress limits. In this study, algebraic, closed-form solutions for calculating the thermal stresses resulting from radial thermal expansion mismatch around a cylindrical fastener are developed. These solutions permit a designer to quickly evaluate many combinations of materials for the fastener and the structure. Using the algebraic equations developed, material properties and joint geometry were varied to determine their effect on thermal stresses. Finite element analyses were used to verify that the closed-form solutions derived give the correct thermal stress distribution around a cylindrical fastener and to investigate the effect of some of the simplifying assumptions made in developing the closed-form solutions for thermal stresses.

Z-2 Threaded Insert Design and Testing Abstract

NASA Technical Reports Server (NTRS)

Rhodes, RIchard; Graziosi, Dave; Jones, Bobby; Ferl, Jinny; Scarborough, Steve; Sweeney, Mitch

2016-01-01

The Z-2 Prototype Planetary Extravehicular Space Suit Assembly is a continuation of NASA's Z series of spacesuits. The Z-2 is another step in the NASA's technology development roadmap leading to human exploration of the Martian surface. To meet a more challenging set of requirements than previous suit systems standard design features, such as threaded inserts, have been re-analyzed and improved. NASA's Z-2 prototype space suit contains several components fabricated from an advanced hybrid composite laminate consisting of IM10 carbon fiber and fiber glass. One requirement NASA levied on the suit composites was the ability to have removable, replaceable helicoil inserts to which other suit components would be fastened. An approach utilizing bonded in inserts with helicoils inside of them was implemented. The design of the interface flanges of the composites allowed some of the inserts to be a "T" style insert that was installed through the entire thickness of the laminate. The flange portion of the insert provides a mechanical lock as a redundancy to the adhesive aiding in the pullout load that the insert can withstand. In some locations it was not possible to utilize at "T" style insert and a blind insert was used instead. These inserts rely completely on the bond strength of the adhesive to resist pullout. It was determined during the design of the suit that the inserts did not need to withstand loads induced from pressure cycling but instead tension induced from torqueing the screws to bolt on hardware which creates a much higher stress on them. Bolt tension is determined by dividing the torque on the screw by a k value multiplied by the thread diameter of the bolt. The k value is a factor that accounts for friction in the system. A common value used for k for a non-lubricated screw is 0.2. The k value can go down by as much as 0.1 if the screw is lubricated which means for the same torque, a much larger tension could be placed on the bolt and insert. This paper summarizes testing that was performed to determine a k value for helicoil inserts in the Z2 suit and how the insert design was modified to resist a higher pull out tension.

Blind Fastener Is Easy To Install

NASA Technical Reports Server (NTRS)

Peterson, S. A.

1982-01-01

Panels, sheets, doors and other structures could be easily attached to and removed from mating part by proposed new fastener. Fastener is permanently anchored in removable part only. Its protruding end is inserted into a hole in mating part. When wedge pin is screwed tightly closed, segmented collar contracts or expands to release parts or to grip them. Installation has no loose parts, and no rear nut is needed.

Comparing the Methodologies in ASTM G198 Using Combined Hygrothermal-Corrosion Modeling

Treesearch

Samuel L. Zelinka

2013-01-01

ASTM G198, “Standard test method for determining the relative corrosion performance of driven fasteners in contact with treated wood,” was accepted by consensus and published in 2011. The method has two different exposure conditions for determining fastener corrosion performance in treated wood. The first method places the wood and embedded fasteners in a...

Comparison of the corrosion of fasteners embedded in wood measured in outdoor exposure with the predictions from a combined hygrothermal-corrosion model

Treesearch

Samuel L. Zelinka; Samuel V. Glass; Charles R. Boardman; Dominique Derome

2016-01-01

This paper examines the accuracy of a recently developed hygrothermal-corrosion model which predictsthe corrosion of fasteners embedded in wood by comparing the results of the model to a one year fieldtest. Steel and galvanized steel fasteners were embedded into untreated and preservative treated woodand exposed outdoors while weather data were collected. Qualitatively...

75 FR 35611 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-23

... one-time high frequency eddy current inspection of fastener holes for cracks at the left and right... frequency eddy current inspection of fastener holes for cracks at the left and right side wing rear spar... frequency eddy current inspection for cracking of fastener holes at the left and right side wing rear spar...

75 FR 2831 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-19

... proposed AD would require a one-time high frequency eddy current inspection of fastener holes for cracks at... high frequency eddy current inspection of fastener holes for cracking at the left and right side wing... of this AD, do a one-time high frequency eddy current inspection for cracking of fastener holes at...

The industrial water footprint of zippers.

PubMed

Zhang, Yin; Wu, Xiong Ying; Wang, Lai Li; Ding, Xue Mei

2014-01-01

Industrial production of apparel consumes large quantity of freshwater and discharges effluents that intensify the problem of freshwater shortage and water pollution. The industrial water footprint (IWF) of a piece of apparel includes the water footprint (WF) of the fabric, apparel accessories (e.g. zipper, fastener, sewing thread) and industrial production processes. The objective of this paper is to carry out a pilot study on IWF accounting for three kinds of typical zipper (i.e. metal zipper, polyethylene terephthalate (PET) zipper and polyoxymethylene copolymer (Co-POM) zipper) that are commonly used for apparel production. The results reveal that product output exerts a remarkable influence on zipper's average IWF. Metal zipper has the largest IWF and followed by Co-POM zipper and PET zipper. Painting, dyeing and primary processing are the top three water-consuming processes and contribute about 90% of the zipper's IWF. Painting consumes the largest amount of freshwater among all processes and occupies more than 50% of the zipper's IWF. In addition, the grey water footprint (WFgrey) provides the greatest contribution, more than 80%, to the zipper's IWF. Based on these results, this paper also provides several strategies aimed at water economization and pollution reduction during industrial production of zipper.

Modeling Adhesive Anchors in a Discrete Element Framework

PubMed Central

Marcon, Marco; Vorel, Jan; Ninčević, Krešimir; Wan-Wendner, Roman

2017-01-01

In recent years, post-installed anchors are widely used to connect structural members and to fix appliances to load-bearing elements. A bonded anchor typically denotes a threaded bar placed into a borehole filled with adhesive mortar. The high complexity of the problem, owing to the multiple materials and failure mechanisms involved, requires a numerical support for the experimental investigation. A reliable model able to reproduce a system’s short-term behavior is needed before the development of a more complex framework for the subsequent investigation of the lifetime of fasteners subjected to various deterioration processes can commence. The focus of this contribution is the development and validation of such a model for bonded anchors under pure tension load. Compression, modulus, fracture and splitting tests are performed on standard concrete specimens. These serve for the calibration and validation of the concrete constitutive model. The behavior of the adhesive mortar layer is modeled with a stress-slip law, calibrated on a set of confined pull-out tests. The model validation is performed on tests with different configurations comparing load-displacement curves, crack patterns and concrete cone shapes. A model sensitivity analysis and the evaluation of the bond stress and slippage along the anchor complete the study. PMID:28786964

Payload Launch Lock Mechanism

NASA Technical Reports Server (NTRS)

Young, Ken (Inventor); Hindle, Timothy (Inventor)

2014-01-01

A payload launch lock mechanism includes a base, a preload clamp, a fastener, and a shape memory alloy (SMA) actuator. The preload clamp is configured to releasibly restrain a payload. The fastener extends, along an axis, through the preload clamp and into the base, and supplies a force to the preload clamp sufficient to restrain the payload. The SMA actuator is disposed between the base and the clamp. The SMA actuator is adapted to receive electrical current and is configured, upon receipt of the electrical current, to supply a force that causes the fastener to elongate without fracturing. The preload clamp, in response to the fastener elongation, either rotates or pivots to thereby release the payload.

76 FR 47430 - Airworthiness Directives; Airbus Model A300 B4-600, A300 B4-600R, and A300 F4-600R Series...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-05

...], reported the failure during a wind tunnel test of a balance weight fastening screw on the RAT turbine cover... balance weight fastening screw on the RAT turbine cover during a wind tunnel test. After investigation, it... during a wind tunnel test of a balance weight fastening screw on the RAT turbine cover. After...

Alloy and composition dependence of hydrogen embrittlement susceptibility in high-strength steel fasteners

NASA Astrophysics Data System (ADS)

Brahimi, S. V.; Yue, S.; Sriraman, K. R.

2017-06-01

High-strength steel fasteners characterized by tensile strengths above 1100 MPa are often used in critical applications where a failure can have catastrophic consequences. Preventing hydrogen embrittlement (HE) failure is a fundamental concern implicating the entire fastener supply chain. Research is typically conducted under idealized conditions that cannot be translated into know-how prescribed in fastener industry standards and practices. Additionally, inconsistencies and even contradictions in fastener industry standards have led to much confusion and many preventable or misdiagnosed fastener failures. HE susceptibility is a function of the material condition, which is comprehensively described by the metallurgical and mechanical properties. Material strength has a first-order effect on HE susceptibility, which increases significantly above 1200 MPa and is characterized by a ductile-brittle transition. For a given concentration of hydrogen and at equal strength, the critical strength above which the ductile-brittle transition begins can vary due to second-order effects of chemistry, tempering temperature and sub-microstructure. Additionally, non-homogeneity of the metallurgical structure resulting from poorly controlled heat treatment, impurities and non-metallic inclusions can increase HE susceptibility of steel in ways that are measurable but unpredictable. Below 1200 MPa, non-conforming quality is often the root cause of real-life failures. This article is part of the themed issue 'The challenges of hydrogen and metals'.

76 FR 25259 - Airworthiness Directives; Airbus Model A300 B4-600, A300 B4-600R, and A300 F4-600R Series...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-04

...], reported the failure during a wind tunnel test of a balance weight fastening screw on the RAT turbine cover... balance weight fastening screw on the RAT turbine cover during a wind tunnel test. After investigation, it... failure during a wind tunnel test of a balance weight fastening screw on the RAT turbine cover. After...

Design Methodology for Bonded-Bolted Composite Joints. Volume I. Analysis Derivations and Illustrative Solutions

DTIC Science & Technology

1982-02-01

EXPERIMENTAL EVIDENCE ...... ....... ....... ....... ... 27 2.6 LOAD REDISTRIBUTION DUE TO DISBONDS IN ADHESIVE IN STEPPED-LAP JOINTS...SINGLE FASTENER " . ;39 3.4 LOAD SHARING BETWEEN MULTIRUW FASTENERS.."."..-.."." ൴ 3.5 FAILURE CRITERIA AT FASTENER HOLES . . ... 3.6 EXPERIMENTAL ...PLASTIC C. PERFECTLY ELASTIC THROUGHOUT A. ULL PLSTC SEAR TRS•WITHOUT $1IGN REVERSAL WITHOUT S:IG13 REVERSAL IOR FULLY NEGATIVE QUIVALENT ) (OR FULLY

Development of Technology for Modernizing Depot Handling of Fasteners

DTIC Science & Technology

1992-01-28

EVALUATION, 53 COUNTERFEIT FASTENERS, SENSORS *7. $CUWT CASSICATION I. SlCUIITY ,LASSIFICA,1ON 19. SECU’ITY UAWFIuIATlON 20. UM1TATION OQ AISTRACT OP...Handling of Fasteners for Detection of Counterfeits and Inventory Control submitted by the University of Detroit in response to PRDA 90-01 released by...This report details the investigation into the problems and the identification of a solution methodology. 6 COUNTERFEIT UNKNOWN MISMATCHED PARTS PARTS

Computer implemented method, and apparatus for controlling a hand-held tool

NASA Technical Reports Server (NTRS)

Wagner, Kenneth William (Inventor); Taylor, James Clayton (Inventor)

1999-01-01

The invention described here in is a computer-implemented method and apparatus for controlling a hand-held tool. In particular, the control of a hand held tool is for the purpose of controlling the speed of a fastener interface mechanism and the torque applied to fasteners by the fastener interface mechanism of the hand-held tool and monitoring the operating parameters of the tool. The control is embodied in intool software embedded on a processor within the tool which also communicates with remote software. An operator can run the tool, or through the interaction of both software, operate the tool from a remote location, analyze data from a performance history recorded by the tool, and select various torque and speed parameters for each fastener.

Pneumovesical ureteric reimplantation using T-fastener: A modification for bladder wall anchorage.

PubMed

Lau, Chin Tung; Lan, Lawrence Chuen Leung; Wong, Kenneth Kak Yuen; Tam, Paul

2017-06-01

Bladder anchoring during pneumovesical ureteric reimplantation (PUR) can be difficult. Here we describe our new technique using a T-fastener (Kimberly Clark, Irving, TX, USA) to tackle this problem. A T-fastener has been applied to all patients who underwent PUR in our center since 2011. Seventeen consecutive cases were performed between 2011 and 2015. No bladder dislodgement or air leak was observed in any of the operations. No morbidity or mortality has been associated with the use of T-fasteners. In our experience, this technique is simple to learn and transferrable. It decreases intraoperative complications and helps to climb the learning curve. Copyright © 2017 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Detection of damaged supports under railway track based on frequency shift

NASA Astrophysics Data System (ADS)

Wang, Longqi; Zhang, Yao; Lie, Seng Tjhen

2017-03-01

In railway transportation systems, the tracks are usually fastened on sleepers which are supported by the ballast. A lot of research has been conducted to guarantee the safety of railway track because of its importance, and more concern is expressed about monitoring of track itself such as railway level and alignment. The ballast and fasteners which provide strong support to the railway track are important as well whereas the detection of loose or missing fasteners and damaged ballast mainly relies on visual inspection. Although it is reliable when the fastener is missing and the damaged ballast is on the surface, it provides less help if the fastener is only loose and the damaged ballast is under the sleepers, which are however frequently observed in practice. This paper proposes an approach based on frequency shift to identify the damaged supports including the loose or missing fasteners and damaged ballast. In this study, the rail-sleeper-ballast system is modeled as an Euler beam evenly supported by a series of springs, the stiffness of which are reduced when the fastener is loose or missing and the ballast under the sleepers is damaged. An auxiliary mass is utilized herein and when it is mounted on the beam, the natural frequencies of the whole system will change with respect to the location of the auxiliary mass. The auxiliary mass induced frequency shift is analyzed and it is found the natural frequencies change periodically when the supports are undamaged, whereas the periodicity will be broken due to damaged supports. In fact, the natural frequencies drop clearly when the auxiliary mass moves over the damaged support. A special damage index only using the information of the damaged states is proposed and both numerical and experimental examples are carried out to validate the proposed method.

Behaviour and Analysis of Mechanically Fastened Joints in Composite Structures

DTIC Science & Technology

1988-03-01

Safety Factors for Use When Designing bolted Joints In GRP," Composites , April 1979, pp. M376. 93. Dastln, S., "Joining and Machining Techniques... MACHINE SPACER LOCKmm STEEL PLATE FASTENER 203 mm OR DOWEL FiN EXTENSOMETER EXTENSOMETER TGAUGE LENGTH ATTACHMENT COMPOSITE - PLATE 31 mm p NOTE: NOT TO...No.427 Behaviour and Analysis of Mechanically Fastened Joints in Composite Structures DTIC CXVTflUTION STATEME~r £ELECTE Approved fm Vubhc sIlam l JUL

System for tamper identification

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

Bobbitt, III, John Thomas; Weeks, George E.

2017-09-05

A system for tamper identification. A fastener has a tamper identification surface with a unique grain structure that is altered if the fastener is removed or otherwise exposed to sufficient torque. After a period of time such as e.g., shipment and/or storage of the sealed container, a determination of whether tampering has occurred can be undertaken by examining the grain structure to determine if it has changed since the fastener was used to seal the container or secure the device.

30 CFR 18.32 - Fastenings-additional requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction... or for making electrical connections. (g) The acceptable sizes for and spacings of fastenings shall...

Spline screw payload fastening system

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

1993-01-01

A system for coupling an orbital replacement unit (ORU) to a space station structure via the actions of a robot and/or astronaut is described. This system provides mechanical and electrical connections both between the ORU and the space station structure and between the ORU and the ORU and the robot/astronaut hand tool. Alignment and timing features ensure safe, sure handling and precision coupling. This includes a first female type spline connector selectively located on the space station structure, a male type spline connector positioned on the orbital replacement unit so as to mate with and connect to the first female type spline connector, and a second female type spline connector located on the orbital replacement unit. A compliant drive rod interconnects the second female type spline connector and the male type spline connector. A robotic special end effector is used for mating with and driving the second female type spline connector. Also included are alignment tabs exteriorally located on the orbital replacement unit for berthing with the space station structure. The first and second female type spline connectors each include a threaded bolt member having a captured nut member located thereon which can translate up and down the bolt but are constrained from rotation thereabout, the nut member having a mounting surface with at least one first type electrical connector located on the mounting surface for translating with the nut member. At least one complementary second type electrical connector on the orbital replacement unit mates with at least one first type electrical connector on the mounting surface of the nut member. When the driver on the robotic end effector mates with the second female type spline connector and rotates, the male type spline connector and the first female type spline connector lock together, the driver and the second female type spline connector lock together, and the nut members translate up the threaded bolt members carrying the first type electrical connector up to the complementary second type connector for interconnection therewith.

Experimental analysis of thread movement in bolted connections due to vibrations

NASA Technical Reports Server (NTRS)

Ramsey, G. ED; Jenkins, Robert C.

1995-01-01

This is the final report of research project NAS8-39131 #33 sponsored by NASA's George C. Marshall Space Flight Center (MSFC) and carried out by the Civil Engineering Department of Auburn University (Auburn, Alabama) and personnel of MSFC. The objective of this study was to identify the main design parameters contributing to the loosening of bolts due to vibration and to identify their relative importance and degree of contribution to bolt loosening. Vibration testing was conducted on a shaketable with a controlled-random input in the dynamic testing laboratory of the Structural Test Division of MSFC. Test specimens which contained one test bolt were vibrated for a fixed amount of time and a percentage of pre-load loss was measured. Each specimen tested implemented some combination of eleven design parameters as dictated by the design of experiment methodology employed. The eleven design parameters were: bolt size (diameter), lubrication on bolt, hole tolerance, initial pre-load, nut locking device, grip length, thread pitch, lubrication between mating materials, class of fit, joint configuration, and mass of configuration. These parameters were chosen for this experiment because they are believed to be the design parameters having the greatest impact on bolt loosening. Two values of each design parameter were used and each combination of parameters tested was subjected to two different directions of vibration and two different g-levels of vibration. One replication was made for each test to gain some indication of experimental error and repeatability and to give some degree of statistical credibility to the data, resulting in a total of 96 tests being performed. The results of the investigation indicated that nut locking devices, joint configuration, fastener size, and mass of configuration were significant in bolt loosening due to vibration. The results of this test can be utilized to further research the complex problem of bolt loosening due to vibration.

High temperature turbine engine structure

DOEpatents

Boyd, Gary L.

1992-01-01

A hybrid ceramic/metallic fastener (bolt) includes a headed ceramic shank carrying a metallic end termination fitting. A conventional cap screw threadably engages the termination fitting to apply tensile force to the fastener.

High temperature turbine engine structure

DOEpatents

Boyd, Gary L.

1991-01-01

A hybrid ceramic/metallic fastener (bolt) includes a headed ceramic shank carrying a metallic end termination fitting. A conventional cap screw threadably engages the termination fitting to apply tensile force to the fastener.

49 CFR 230.80 - Cabs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... pipe, with properly rated valves and fittings. Live steam heating radiators must not be fastened to the cab. Exhaust steam radiators may be fastened to the cab. (c) Oil-burning steam locomotives. If the cab...

78 FR 22215 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-15

... necessary; a one-time eddy current inspection of certain fastener holes for cracking, and repair if... realignment if necessary; a one-time eddy current inspection of certain fastener holes for cracking, and...

Lunar surface vehicle model competition

NASA Technical Reports Server (NTRS)

1990-01-01

During Fall and Winter quarters, Georgia Tech's School of Mechanical Engineering students designed machines and devices related to Lunar Base construction tasks. These include joint projects with Textile Engineering students. Topics studied included lunar environment simulator via drop tower technology, lunar rated fasteners, lunar habitat shelter, design of a lunar surface trenching machine, lunar support system, lunar worksite illumination (daytime), lunar regolith bagging system, sunlight diffusing tent for lunar worksite, service apparatus for lunar launch vehicles, lunar communication/power cables and teleoperated deployment machine, lunar regolith bag collection and emplacement device, soil stabilization mat for lunar launch/landing site, lunar rated fastening systems for robotic implementation, lunar surface cable/conduit and automated deployment system, lunar regolith bagging system, and lunar rated fasteners and fastening systems. A special topics team of five Spring quarter students designed and constructed a remotely controlled crane implement for the SKITTER model.

Ballistic parameters and trauma potential of direct-acting, powder-actuated fastening tools (nail guns).

PubMed

Frank, Matthias; Franke, Ernst; Schönekess, Holger C; Jorczyk, Jörn; Bockholdt, Britta; Ekkernkamp, Axel

2012-03-01

Since their introduction in the 1950s in the construction and building trade, powder-actuated fastening tools (nail guns) are of forensic and traumatological importance. There are countless reports on both accidental and intentional injuries and fatalities caused by these tools in medical literature. While the ballistic parameters of so-called low-velocity fastening tools, where the expanding gases act on a captive piston that drives the fastener into the material, are well known, ballistic parameters of "high-velocity" tools, which operate like a firearm and release the energy of the propellant directly on the fastener, are unknown. Therefore, it was the aim of this work to investigate external ballistic parameters of cal. 9 and 6-mm fastening bolts discharged from four different direct-acting nail guns (Type Ideal, Record Piccolo S, Rapid Hammer R300, Titan Type 1). Average muzzle velocity ranged from 400 to 580 m/s, while average kinetic energy of the projectiles ranged from 385 to 547 J. Mean energy density of the projectiles ranged from 9 to 18 J/mm(2). To conclude, this work demonstrates that the muzzle velocity of direct-acting high-velocity tools is approximately five times higher than the muzzle velocity of piston-type tools. Hence, the much-cited comparison to the ballistic parameters of a cal. 22 handgun might be understated and a comparison to the widespread and well-known cal. 9 mm Luger might be more appropriate.

Stirling Convertor Fasteners Reliability Quantification

NASA Technical Reports Server (NTRS)

Shah, Ashwin R.; Korovaichuk, Igor; Kovacevich, Tiodor; Schreiber, Jeffrey G.

2006-01-01

Onboard Radioisotope Power Systems (RPS) being developed for NASA s deep-space science and exploration missions require reliable operation for up to 14 years and beyond. Stirling power conversion is a candidate for use in an RPS because it offers a multifold increase in the conversion efficiency of heat to electric power and reduced inventory of radioactive material. Structural fasteners are responsible to maintain structural integrity of the Stirling power convertor, which is critical to ensure reliable performance during the entire mission. Design of fasteners involve variables related to the fabrication, manufacturing, behavior of fasteners and joining parts material, structural geometry of the joining components, size and spacing of fasteners, mission loads, boundary conditions, etc. These variables have inherent uncertainties, which need to be accounted for in the reliability assessment. This paper describes these uncertainties along with a methodology to quantify the reliability, and provides results of the analysis in terms of quantified reliability and sensitivity of Stirling power conversion reliability to the design variables. Quantification of the reliability includes both structural and functional aspects of the joining components. Based on the results, the paper also describes guidelines to improve the reliability and verification testing.

29 CFR 1915.135 - Powder actuated fastening tools.

Code of Federal Regulations, 2013 CFR

2013-07-01

... tile, surface hardened steel, glass block, live rock, face brick or hollow title. (5) Fasteners shall... into materials such as brick or concrete within 3 inches of the unsupported edge or corner, or into...

29 CFR 1915.135 - Powder actuated fastening tools.

Code of Federal Regulations, 2012 CFR

2012-07-01

... tile, surface hardened steel, glass block, live rock, face brick or hollow title. (5) Fasteners shall... into materials such as brick or concrete within 3 inches of the unsupported edge or corner, or into...

29 CFR 1915.135 - Powder actuated fastening tools.

Code of Federal Regulations, 2011 CFR

2011-07-01

... tile, surface hardened steel, glass block, live rock, face brick or hollow title. (5) Fasteners shall... into materials such as brick or concrete within 3 inches of the unsupported edge or corner, or into...

29 CFR 1915.135 - Powder actuated fastening tools.

Code of Federal Regulations, 2014 CFR

2014-07-01

... tile, surface hardened steel, glass block, live rock, face brick or hollow title. (5) Fasteners shall... into materials such as brick or concrete within 3 inches of the unsupported edge or corner, or into...

Proceedings : Direct Fixation Fastener Workshop

DOT National Transportation Integrated Search

1985-06-01

This report is a collection of papers and discussion transcripts from a workshop on direct fixation fastener systems (DFFS) that are increasingly being used in the construction of modern rail transit systems and system extensions. Preservice testing,...

Quick-sealing design for radiological containment

DOEpatents

Rampolia, Donald S.; Speer, Elmer

1990-01-01

A quick-sealing assembly and method for forming an adhesive seal on opposite sides of a mechanical seal for a flexible containment bag of the type used for working with radioactively contaminated objects. The assembly includes an elongated mechanical fastener having opposing engaging members affixed at a predetermined distance from each of the elongated edges, with an adhesive layer formed between the mechanical fastener and the elongated edge such that upon engagement of the mechanical fastener and adhesive layers to opposing containment fabric, a neat triple hermetic seal is formed.

Quick-sealing design for radiological containment

DOEpatents

Rampolla, Donald S.; Speer, Elmer

1991-01-01

A quick-sealing assembly and method for forming an adhesive seal on opposite sides of a mechanical seal for a flexible containment bag of the type used for working with radioactively contaminated objects. The assembly includes an elongated mechanical fastener having opposing engaging members affixed at a predetermined distance from each of the elongated edges, with an adhesive layer formed between the mechanical fastener and the elongated edge such that upon engagement of the mechanical fastener and adhesive layers to opposing containment fabric, a neat triple hermetic seal is formed.

Torque Tension Testing of Fasteners used for NASA Flight Hardware Applications

NASA Technical Reports Server (NTRS)

Hemminger, Edgar G.; Posey, Alan J.; Dube, Michael J.

2014-01-01

The effect of various lubricants and other compounds on fastener torque-tension relationships is evaluated. Testing was performed using a unique test apparatus developed by Posey at the NASA Goddard Space Flight Center. A description of the test methodology, including associated data collection and analysis will be presented. Test results for 300 series CRES and A286 heat resistant fasteners, torqued into various types of inserts will be presented. The primary objective of this testing was to obtain torque-tension data for use on NASA flight projects.

Development of a truss joint for robotic assembly of space structures

NASA Technical Reports Server (NTRS)

Parma, George F.

1992-01-01

This report presents the results of a detailed study of mechanical fasteners which were designed to facilitate robotic assembly of structures. Design requirements for robotic structural assembly were developed, taking into account structural properties and overall system design, and four candidate fasteners were designed to meet them. These fasteners were built and evaluated in the laboratory, and the Hammer-Head joint was chosen as superior overall. It had a high reliability of fastening under misalignments of 2.54 mm (0.1 in) and 3 deg, the highest end fixity (2.18), the simplest end effector, an integral capture guide, good visual verification, and the lightest weight (782 g, 1.72 lb). The study found that a good design should incorporate chamfers sliding on chamfers, cylinders sliding on chamfers, and hard surface finishes on sliding surfaces. The study also comments on robot flexibility, sag, hysteresis, thermal expansion, and friction which were observed during the testing.

Willingness to use safety belt and levels of injury in car accidents.

PubMed

de Lapparent, Matthieu

2008-05-01

In this article, we develop a bivariate ordered Probit model to analyze the decision to fasten the safety belt in a car and the resulting severity of accidents if it happens. The approach takes into account the fact that the decision to fasten the safety belt has a direct causal effect on the category of injury if an accident happens. Our application to a sample drawn from the database of French accident reports in 2003 for three populations of car users (drivers, front passengers, rear passengers) shows that fastening the safety belt is significantly related to a decrease in severe injuries but it shows also that these car users compensate partly for this safety benefit. Furthermore, it is observed that demographic characteristics of car users, as well as transport facilities, play important roles in decisions to fasten safety belts and in the eventual resulting accident injuries.

Consolidation of graphite thermoplastic textile preforms for primary aircraft structure

NASA Technical Reports Server (NTRS)

Suarez, J.; Mahon, J.

1991-01-01

The use of innovative cost effective material forms and processes is being considered for fabrication of future primary aircraft structures. Processes that have been identified as meeting these goals are textile preforms that use resin transfer molding (RTM) and consolidation forming. The Novel Composites for Wing and Fuselage Applications (NCWFA) program has as its objective the integration of innovative design concepts with cost effective fabrication processes to develop damage-tolerant structures that can perform at a design ultimate strain level of 6000 micro-inch/inch. In this on-going effort, design trade studies were conducted to arrive at advanced wing designs that integrate new material forms with innovative structural concepts and cost effective fabrication methods. The focus has been on minimizing part count (mechanical fasteners, clips, number of stiffeners, etc.), by using cost effective textile reinforcement concepts that provide improved damage tolerance and out-of-plane load capability, low-cost resin transfer molding processing, and thermoplastic forming concepts. The fabrication of representative Y spars by consolidation methods will be described. The Y spars were fabricated using AS4 (6K)/PEEK 150g commingled angle interlock 0/90-degree woven preforms with +45-degree commingled plies stitched using high strength Toray carbon thread and processed by autoclave consolidation.

Preliminary Test Results of a Non-Contacting Finger Seal on a Herringbone-Grooved Rotor

NASA Technical Reports Server (NTRS)

Proctor, Margaret P.; Delgado, Irebert R.

2009-01-01

The baseline non-contacting finger seal is a NASA patented design. The primary difference between it and Gul Aroras design patented by AlliedSignal is that there are no lift pads on the high pressure fingers. The baseline non-contacting finger seal is comprised of a back plate, aft spacer, aft (or low pressure) finger element, forward (or high pressure) finger element, forward spacer, and front plate. The components are held together with 20 flat head screws. A typical seal would have a back plate of approximately the same thickness as the front plate and would be riveted together. The thicker back plate allows use of threaded fasteners so that different finger elements can be tested without having to replace all the individual seal components. The finger elements are essentially washers made of thin sheet stock with multiple curved slots machined around the inner diameter to form the fingers. They are clocked so that the fingers of one cover the slots of the other. The aft finger element fingers have axial extensions or "lift pads" at the seal id that are concentric to the rotor. The fingers act as cantilever beams and flex in response to rotor dynamic motion and radial growth of the rotor due to centrifugal or thermal forces.

Removal torque of zirconia abutment screws under dry and wet conditions.

PubMed

Nigro, Frederico; Sendyk, Claudio L; Francischone, Carlos Eduardo; Francischone, Carlos Eduardo

2010-01-01

The aim of this study was to verify whether screw abutment lubrication can generate higher preload values compared to non-lubricated screws, a titanium abutment was screwed onto an implant analog and scanned with the Procera System to generate 20 zirconia abutments. MKIII Brånemark implants were clamped to a precision torque device, and the abutments were distributed in dry and wet groups with 10 specimens each. In the wet groups, the inner threads of the implants were filled with artificial saliva. All abutments were fastened with a Torqtite screw under 32 Ncm. Ten detorque measurements were performed per group pushing the reverse button of the Torque controller soon after screw tightening with values registered. The mean detorque values were calculated and compared by a Student's t test (α=0.05). The wet condition presented significantly higher mean detorque than the dry condition (31.5 ± 1.2 versus 27.5 ± 1.5 Ncm, respectively; p=0.0000024). In conclusion, there was always a loss in the initial torque values when the removal torque was measured under both conditions. The wet condition presented higher mean torque than the dry condition. Better preload values were established in the wet group, suggesting that the abutment screw must be lubricated in saliva to avoid further loosening.

Testing and evaluation of Vespel up to 450 deg F when used in nuts and bolts as a self-locking element

NASA Technical Reports Server (NTRS)

Wood, C. M.

1984-01-01

The object of this investigation was to evaluate Vespel for potential application on the Solid Rocket Booster to replace all-metal deformed self-locking nuts and anchor nuts and be used as self-locking elements for bolts and screws. The Vespel self-locking elements were tested for prevailing torque retention at room temperature, after heating to 450 F and exposure for 3 hr, breakaway torque at 450 F and for vibration at a level consistent with the maximum expected on the SRB at lift-off and reentry. The investigation revealed Vespel has properties that can provide a self-locking capability for threaded fasteners up to 450 F and it can be used in nuts and anchor nuts for installation on the SRB. Vespel elements in bolts did not meet all our SRB requirements for reuse, however, we have defined a design for Vespel elements in nuts/anchor nuts that fully meets all requirements. It is recommended that No. 1, 1/4 in. and 5/16 in. nuts/anchor nuts be procured for use on the SRB. This system will eliminate the galling problems now encountered and achieve a much higher reuse life than the present deformed nut design.

[Biomechanical performance of different wires and cable fixation devices in posterior instrumentation for atlantoaxial instability].

PubMed

Liu, Tie-long; Yan, Wang-jun; Han, Yu; Ye, Xiao-jian; Jia, Lian-shun; Li, Jia-shun; Yuan, Wen

2010-05-01

To compare the biomechanical performances of different wires and cable fixation devices in posterior instrumentation for atlantoaxial instability, and test the effect of different fixation strengths and fixation approaches on the surgical outcomes. Six specimens of the atlantoaxial complex (C0-C3) were used to establish models of the normal complex, unstable complex (type II odontoid fracture) and fixed complex. On the wd-5 mechanical testing machine, the parameters including the strength and rigidity of anti-rotation, change and strength of stress, and stability were measured for the normal complex, atlantoaxial instability complex, the new type titanium cable fixation system, Atlas titanium cable, Songer titanium cable, and stainless wire. The strength and rigidity of anti-rotation, change and strength of stress, stability of flexion, extension and lateral bending of the unstable atlantoaxial complex fixed by the new double locking titanium cable fixation system were superior to those of the Songer or Atlas titanium cable (P<0.05) and medical stainless wire (P<0.05). Simultaneous cable fastening on both sides resulted in better fixation effect than successive cable fastening (P<0.05). Better fixation effect was achieved by fastening the specimen following a rest (P<0.05). The fixation effects can be enhanced by increased fastening strengths. The new type double locking titanium cable fixation system has better biomechanical performance than the conventional Songer and Atlas titanium cables. Fastening the unstable specimens after a rest following simultaneous fastening of the specimen on both sides produces better fixation effect.

Reversible fastener clamp load monitor with continuous visual or remote readout

NASA Astrophysics Data System (ADS)

Hodge, Malcolm H.; Kausel, Theodore C., Jr.; Begley, Matthew R.

1998-03-01

SIMS has developed a simple means for detecting and monitoring both absolute and relative clamp load, or bolt tension, in fastener systems. More than twenty-five percent of automotive failures are known to be due to undetected loss of fastener clamp load. While the equivalent aerospace maintenance statistics are not known, the average automobile has 3,500 fasteners while a Boeing 747 has closer to one million. It is therefore anticipated that the new SensaBolt clamp load tracking system could find wide applications in the aerospace arena. We describe a visually-evident and retrofitted clamp load monitoring design which is based on the differential joint substrate compression at, and immediately adjacent to, the fastener location. This intrinsically-accurate indicator does not necessarily require alteration in either the bolt or nut geometries, thereby facilitating product introduction and retrofit in aging aircraft applications. In addition, SensaBolt's sole reliance on substrate compression renders it more accurate then torque wrench or turn-of-nut techniques. Readout may be accomplished by any of three principal methods: for those applications with ease of access to the sensor, loss of tension can be determined by direct visual inspection. Application of a standard wrench can then be made to restore the fastener's proper tightness, per the SensaBolt indicators. In those instances where line-of-sight is unimpeded and more formal inspection is desired, the SensaBolt may be interrogated by a laser scanner bar code reader. Finally, SensaBolt may be addressed by the SIMS fiber optic harness for those instances where full-time remote interrogation is desired.

Mechanistic design of concrete crossties and fastening systems - Phase 1.

DOT National Transportation Integrated Search

2017-04-28

The objective of this project is the development and deployment of resilient concrete crossties and fastening systems for heavy haul freight, intercity passenger, and rail transit applications. : For a variety of reasons, concrete crossties are a dom...

Performance of Rail Fastening Systems on an Open-Deck Bridge

DOT National Transportation Integrated Search

2018-02-01

Transportation Technology Center, Inc. (TTCI) monitored the performance of rail fasteners on an open-deck bridge and its approaches, located at Norfolk Southern Corporations (NS's) eastern mega site. The project was co-sponsored by the Federal Rai...

29 CFR 1915.135 - Powder actuated fastening tools.

Code of Federal Regulations, 2010 CFR

2010-07-01

... into materials such as brick or concrete within 3 inches of the unsupported edge or corner, or into... 2×4 inch lumber to a concrete surface, fasteners of greater than 7/32 inch shank diameter shall not...

Constant time worker thread allocation via configuration caching

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

Eichenberger, Alexandre E; O'Brien, John K. P.

Mechanisms are provided for allocating threads for execution of a parallel region of code. A request for allocation of worker threads to execute the parallel region of code is received from a master thread. Cached thread allocation information identifying prior thread allocations that have been performed for the master thread are accessed. Worker threads are allocated to the master thread based on the cached thread allocation information. The parallel region of code is executed using the allocated worker threads.

Modeling the lateral load distribution for multiple concrete crossties and fastening systems.

DOT National Transportation Integrated Search

2017-01-31

The objective of this project was to further investigate the performance of concrete crosstie and : fastening system under vertical and lateral wheel load using finite element analysis, and explore : possible improvement for current track design stan...

Development of a 3D FEM model for concrete tie and fastening systems.

DOT National Transportation Integrated Search

2015-01-31

This project conducted detailed finite element (FE) modeling of the concrete crosstie and fastening system to better understand the mechanisms through which loads transfer within various track components in the lateral direction. This was completed b...

Detecting hidden exfoliation corrosion in aircraft wing skins using thermography

NASA Astrophysics Data System (ADS)

Prati, John

2000-03-01

A thermal wave (pulse) thermography inspection technique demonstrated the ability to detect hidden subsurface exfoliation corrosion adjacent to countersunk fasteners in aircraft wing skins. In the wing skin, exfoliation corrosion is the result of the interaction between the steel fastener and the aluminum skin material in the presence of moisture. This interaction results in corrosion cracks that tend to grow parallel to the skin surface. The inspection technique developed allows rapid detection and evaluation of hidden (not visible on the surface) corrosion, which extends beyond the head of fastener countersinks in the aluminum skins.

Impact Study of Metal Fasteners in Roofing Assemblies using Three-Dimensional Heat Transfer Analysis

DOE PAGES

Singh, Manan; Gulati, Rupesh; Ravi, Srinivasan; ...

2016-11-29

Heat transfer analysis was performed on typical roofing assemblies using HEAT3, a three-dimensional heat transfer analysis software. The difference in heat transferred through the roofing assemblies considered is compared between two cases - without any steel fasteners and with steel fasteners. In the latter case, the metal roofing fasteners were arranged as per Factor Mutual Global (FMG) approvals, in the field, perimeter, and corner zones of the roof. The temperature conditions used for the analysis represented summer and winter conditions for three separate Climate Zones (CZ) namely Climate Zone 2 or CZ2 represented by Orlando, FL; CZ3 represented by Atlanta,more » GA; and CZ6 zone represented by St. Paul, MN. In all the climatic conditions, higher energy transfer was observed with increase in the number of metal fasteners attributed to high thermal conductivity of metals as compared to the insulation and other materials used in the roofing assembly. This difference in heat loss was also quantified in the form of percentage change in the overall or effective insulation of the roofing assembly for better understanding of the practical aspects. Besides, a comparison of 2D heat transfer analysis (using THERM software) and 3D analysis using HEAT3 is also discussed.« less

Impact Study of Metal Fasteners in Roofing Assemblies using Three-Dimensional Heat Transfer Analysis

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

Singh, Manan; Gulati, Rupesh; Ravi, Srinivasan

Heat transfer analysis was performed on typical roofing assemblies using HEAT3, a three-dimensional heat transfer analysis software. The difference in heat transferred through the roofing assemblies considered is compared between two cases - without any steel fasteners and with steel fasteners. In the latter case, the metal roofing fasteners were arranged as per Factor Mutual Global (FMG) approvals, in the field, perimeter, and corner zones of the roof. The temperature conditions used for the analysis represented summer and winter conditions for three separate Climate Zones (CZ) namely Climate Zone 2 or CZ2 represented by Orlando, FL; CZ3 represented by Atlanta,more » GA; and CZ6 zone represented by St. Paul, MN. In all the climatic conditions, higher energy transfer was observed with increase in the number of metal fasteners attributed to high thermal conductivity of metals as compared to the insulation and other materials used in the roofing assembly. This difference in heat loss was also quantified in the form of percentage change in the overall or effective insulation of the roofing assembly for better understanding of the practical aspects. Besides, a comparison of 2D heat transfer analysis (using THERM software) and 3D analysis using HEAT3 is also discussed.« less

A robust multi-frequency mixing algorithm for suppression of rivet signal in GMR inspection of riveted structures

NASA Astrophysics Data System (ADS)

Safdernejad, Morteza S.; Karpenko, Oleksii; Ye, Chaofeng; Udpa, Lalita; Udpa, Satish

2016-02-01

The advent of Giant Magneto-Resistive (GMR) technology permits development of novel highly sensitive array probes for Eddy Current (EC) inspection of multi-layer riveted structures. Multi-frequency GMR measurements with different EC pene-tration depths show promise for detection of bottom layer notches at fastener sites. However, the distortion of the induced magnetic field due to flaws is dominated by the strong fastener signal, which makes defect detection and classification a challenging prob-lem. This issue is more pronounced for ferromagnetic fasteners that concentrate most of the magnetic flux. In the present work, a novel multi-frequency mixing algorithm is proposed to suppress rivet signal response and enhance defect detection capability of the GMR array probe. The algorithm is baseline-free and does not require any assumptions about the sample geometry being inspected. Fastener signal suppression is based upon the random sample consensus (RANSAC) method, which iteratively estimates parameters of a mathematical model from a set of observed data with outliers. Bottom layer defects at fastener site are simulated as EDM notches of different length. Performance of the proposed multi-frequency mixing approach is evaluated on finite element data and experimental GMR measurements obtained with unidirectional planar current excitation. Initial results are promising demonstrating the feasibility of the approach.

Screw-Thread Standards for Federal Services, 1957. Handbook H28 (1957), Part 3

DTIC Science & Technology

1957-09-01

MOUNTING THREADS PHOTOGRAPHIC EQUIPMENT THREADS ISO METRIC THREADS; MISCELLANEOUS THREADS CLASS 5 INTERFERENCE-FIT THREADS, TRIAL STANDARD WRENCH...Bibliography on measurement of pitch diameter by means of wires 60 Appendix 14. Metric screw-thread standards 61 1. ISO thread profiles...61 2. Standard series for ISO metric threads 62 3. Designations for ISO metric threads 62 Tables Page Table XII. 1.—Basic

Fastener Retention Requirements and Practices in Spaceflight Hardware

NASA Technical Reports Server (NTRS)

Dasgupta, Rajib

2004-01-01

This presentation reviews the requirements for safety critical fasteners in spaceflight hardware. Included in the presentation are design guidelines and information for Locking Helicoils, key locked inserts and thinwalled inserts, self locking screws and bolts. locknuts, and a locking adhesives, Loctite and Vibratite.

Measurement Program for Evaluation of Concrete Ties and Fastenings in Transit Track

DOT National Transportation Integrated Search

1979-03-01

This report outlines a measurement program to obtain data on the performance of standard tie designs and associated fastening systems under field service conditions. In addition, the program identifies limited data to be obtained from a wood tie trac...

Dedicated memory structure holding data for detecting available worker thread(s) and informing available worker thread(s) of task(s) to execute

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

Chiu, George L.; Eichenberger, Alexandre E.; O'Brien, John K. P.

The present disclosure relates generally to a dedicated memory structure (that is, hardware device) holding data for detecting available worker thread(s) and informing available worker thread(s) of task(s) to execute.

Re-interpreting Prominences Classified as Tornadoes

NASA Astrophysics Data System (ADS)

Martin, Sara F.; Venkataramanasastry, Aparna

2015-04-01

Some papers in the recent literature identify tornado prominences with barbs of quiescent prominences while papers in the much older historic literature include a second category of tornado prominence that does not correspond to a barb of a quiescent prominence. The latter are described as prominence mass rotating around a nearly vertical axis prior to its eruption and the rotation was verified by spectral measurements. From H alpha Doppler-shifted mass motions recorded at Helio Research or the Dutch Open Telescope, we illustrate how the apparent tornado-like motions, identified with barbs, are illusions in our mind’s eye resulting from poorly resolved counterstreaming threads of mass in the barbs of quiescent prominences. In contrast, we confirm the second category of rotational motion in prominences shortly before and during eruption. In addition, we identify this second category as part of the late phase of a phenomenon called the roll effect in erupting prominences. In these cases, the eruption begins with the sideways rolling of the top of a prominence. As the eruption proceeds the rolling motion propagates down one leg or both legs of the prominence depending on whether the eruption is asymmetric or symmetric respectively. As an asymmetric eruption continues, the longer lasting leg becomes nearly vertical and its rotational motion also continues. If only this phase of the eruption was observed, as in some historic cases, it was called a tornado prominence. However, when we now observe entire eruptions in time-lapse sequences, the similarity to terrestrial tornadoes is lost. We conclude that neither prominence barbs, that give the illusion of rotation, nor the cases of true rotational motion, in the legs of erupting prominences, are usefully described as tornado prominences when the complete prominence structure or complete erupting event is observed.

Improved Concrete Crosstie and Fastening Systems for US High Speed Passenger Rail and Joint Corridors : Volume 1, Project Summary Report

DOT National Transportation Integrated Search

2017-11-01

Rail corridors often experience a wide variety of passenger and freight train loads, track geometry characteristics, and environmental conditions. These factors must be considered when developing an optimized concrete crosstie and fastening sys...

Data Analysis and Instrumentation Requirements for Evaluating Rail Joints and Rail Fasteners in Urban Track

DOT National Transportation Integrated Search

1975-02-01

Rail fasteners for concrete ties and direct fixation and bolted rail joints have been identified as key components for improving track performance. However, the lack of statistical load data limits the development of improved design criteria and eval...

Influence of clamp-up force on the strength of bolted composite joints

NASA Astrophysics Data System (ADS)

Horn, Walter J.; Schmitt, Ron R.

1994-03-01

Composite materials offer the potential for a reduction in the number of individual parts and joints in a structure because large one-piece components can replace multipart assemblies. Nevertheless, there are many situations where composite parts must be joined and often mechanical fasteners provide the only practical method of joining those parts. The long-term strength of mechanically fastened joints of composite members can be directly affected by the clamp-up force of the fastener and thus perhaps by the relaxation of this force due to the viscoelastic character of the composite materials of the joint. Methods for predicting the effect of bolt clamp-up force relaxation on the strength of mechanically fastened joints of thermoplastic composite materials were investigated during the present study. A test program, using two thermoplastic composite materials, was conducted to determine the influence of clamp-up force on joint strength, to measure the relaxation of the joint clamp-up force with time, and to measure the change of joint strength as a function of time.

Detection of fastener loosening in simple lap joint based on ultrasonic wavefield imaging

NASA Astrophysics Data System (ADS)

Gooda Sahib, M. I.; Leong, S. J.; Chia, C. C.; Mustapha, F.

2017-12-01

Joints in aero-mechanical structures are critical elements that ensure the structural integrity but they are prone to damages. Inspection of such joints that have no prior baseline data is really challenging but it can be possibly done using the Ultrasonic Propagation Imager (UPI). The feasibility of applying UPI for detection of loosened fastener is investigated in this study. A simple lap joint specimen made by connecting two pieces of 2.5mm thick SAE304 stainless steel plates using five M6 screws and nuts has been used in this study. All fasteners are tightened to 10Nm but one of them is completely loosened to simulate the damage. The wavefield data is processed into ultrasonic wavefield propagation video and a series of spectral amplitude images. The spectral images showed noticeable amplitude difference at the loosened fastener, hence confirmed the feasibility of using UPI for structural joints inspection. A simple contrast maximization method is also introduced to improve the result.

Track component property tests : property tests volume 1 : rail, tie, and fasteners.

DOT National Transportation Integrated Search

1979-08-01

This report describes the test procedures and the results of tests on the physical properties of rail, tie and fastener. The properties obtained are the bending rigidity of the tie, bending rigidity of the rail in both the vertical and lateral planes...

Structurally compliant microbearing devices and methods thereof

NASA Technical Reports Server (NTRS)

Boedo, Stephen (Inventor); Grande, William (Inventor)

2011-01-01

A microbearing device includes at least one inner bearing structure, at least one outer bearing structure, and one or more fasteners. Each of the one or more fasteners is connected between the inner bearing structure and the outer bearing structure and the inner bearing structure is substantially elastic.

NDI method to locate intergranular corrosion around fastener holes in aluminum wing skins

NASA Astrophysics Data System (ADS)

Rutherford, Paul S.

1998-03-01

Contact between galvanically dissimilar metals, such as cadmium plated steel fasteners and aluminum wing skins are known to be a source of corrosion. There is a design requirement to fill the void between the contacting surfaces of steel fasteners with a wet sealant. However, if the contacting surface is damaged or a void exists between the fastener head and the aluminum skin, moisture can collect and intergranular corrosion may occur along aluminum grain boundaries, which run parallel to the surface of the wing skin. If intergranular corrosion is allowed to propagate, delamination of the thin layers of aluminum, known as exfoliation corrosion will occur. When this intergranular corrosion reaches an exfoliated state, extensive rework is involved in removing the corrosion. This paper discusses the results of a USAF E-3A Engineering Service Task 89-E3B3-16 to develop a nondestructive inspection procedure to detect intergranular corrosion in an incipient state before it reaches exfoliation. Eddy current and ultrasonic inspection techniques were evaluated. A novel ultrasonic pulse echo technique was developed which utilizes a focus transducer with a hand held fixture. Inspections were performed on test parts which were removed from the upper wing skin of a retired 707 which had varying degrees of intergranular and exfoliation corrosion. Inspection results are compared to the results from the mechanical rework of the wing skin and dissection of a wing skin fastener hole.

Skin, Stringer, and Fastener Loads in Buckled Fuselage Panels

NASA Technical Reports Server (NTRS)

Young, Richard D.; Rose, Cheryl A.; Starnes, James H., Jr.

2001-01-01

The results of a numerical study to assess the effect of skin buckling on the internal load distribution in a stiffened fuselage panel, with and without longitudinal cracks, are presented. In addition, the impact of changes in the internal loads on the fatigue life and residual strength of a fuselage panel is assessed. A generic narrow-body fuselage panel is considered. The entire panel is modeled using shell elements and considerable detail is included to represent the geometric-nonlinear response of the buckled skin, cross section deformation of the stiffening components, and details of the skin-string attachment with discrete fasteners. Results are presented for a fixed internal pressure and various combinations of axial tension or compression loads. Results illustrating the effect of skin buckling on the stress distribution in the skin and stringer, and fastener loads are presented. Results are presented for the pristine structure, and for cases where damage is introduced in the form of a longitudinal crack adjacent to the stringer, or failed fastener elements. The results indicate that axial compression loads and skin buckling can have a significant effect on the circumferential stress in the skin, and fastener loads, which will influence damage initiation, and a comparable effect on stress intensity factors for cases with cracks. The effects on stress intensity factors will influence damage propagation rates and the residual strength of the panel.

78 FR 72561 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-03

... and a skin crack in section 41 of the fuselage, and multiple reports of cracked or missing fastener heads. This AD requires repetitive inspections for cracking of the fuselage skin, discrepant fasteners... disbonding and subsequent cracking of the skin panels. DATES: This AD is effective January 7, 2014. The...

76 FR 61036 - Airworthiness Directives; Gulfstream Aerospace LP Model Galaxy and Gulfstream 200 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-03

...-conformity with certified mechanical properties of this fastener can potentially lead to an unsafe condition... hardness. Non-conformity with certified mechanical properties of this fastener can potentially lead to an... resulted from hydrogen embrittlement combined with high hardness. Non-conformity with certified mechanical...

49 CFR 238.429 - Safety appliances.

Code of Federal Regulations, 2012 CFR

2012-10-01

... appliance mechanical strength and fasteners. (1) All handrails, handholds, and sill steps shall be made of 1-inch diameter steel pipe, 5/8-inch thickness steel, or a material of equal or greater mechanical strength. (2) All safety appliances shall be securely fastened to the car body structure with mechanical...

Unitized Nut-and-Washer Assembly

NASA Technical Reports Server (NTRS)

Rossi, P. J.

1986-01-01

Combination nut, washer, and lockwasher secures parts quickly without damaging metal finishes. Nut and lockwasher are captured by bent tabs of flat washer in this concept for unified fastener. Optional perforated tab on flat washer allows easy tagging and storage. Fastener intended for attaching leads and buses to studs on electronic equipment.

25 CFR 307.11 - Certificates fastened to fabrics.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false Certificates fastened to fabrics. 307.11 Section 307.11 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO ALL-WOOL WOVEN FABRICS; USE OF... the hand seal press furnished by the Indian Arts and Crafts Board. ...

Fastener corrosion : testing, research, and design considerations

Treesearch

Douglas R. Rammer; Samuel L. Zelinka; Philip Line

2006-01-01

In 2004, the voluntary removal of chromated copper arsenate (CCA) from residential wood construction raised concern about corrosion of metal fasteners in wood treated with replacement preservatives. Replacement preservatives contain more copper, which may increase corrosion, and do not contain chromates or arsenates, which are known corrosion inhibitors. This paper is...

49 CFR 393.102 - What are the minimum performance criteria for cargo securement devices and systems?

Code of Federal Regulations, 2010 CFR

2010-10-01

... chains, wire rope, steel strapping, synthetic webbing, and cordage) and other attachment or fastening... acceleration in a lateral direction. (2) Working Load limit. Tiedown assemblies (including chains, wire rope, steel strapping, synthetic webbing, and cordage) and other attachment or fastening devices used to...

49 CFR 393.102 - What are the minimum performance criteria for cargo securement devices and systems?

Code of Federal Regulations, 2011 CFR

2011-10-01

... chains, wire rope, steel strapping, synthetic webbing, and cordage) and other attachment or fastening... acceleration in a lateral direction. (2) Working Load limit. Tiedown assemblies (including chains, wire rope, steel strapping, synthetic webbing, and cordage) and other attachment or fastening devices used to...

30 CFR 7.308 - Lockwasher equivalency test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... hole and continuously and uniformly tightened at a speed not to exceed 30 rpm until the fastening's... cycles. (b) Acceptable performance. The minimum torque value required to start removal of the fastening from the installed position (minimum breakway torque) for any cycle of any test sample shall be greater...

30 CFR 7.308 - Lockwasher equivalency test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... hole and continuously and uniformly tightened at a speed not to exceed 30 rpm until the fastening's... cycles. (b) Acceptable performance. The minimum torque value required to start removal of the fastening from the installed position (minimum breakway torque) for any cycle of any test sample shall be greater...

30 CFR 7.308 - Lockwasher equivalency test.

Code of Federal Regulations, 2013 CFR

2013-07-01

... hole and continuously and uniformly tightened at a speed not to exceed 30 rpm until the fastening's... cycles. (b) Acceptable performance. The minimum torque value required to start removal of the fastening from the installed position (minimum breakway torque) for any cycle of any test sample shall be greater...

30 CFR 7.308 - Lockwasher equivalency test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... hole and continuously and uniformly tightened at a speed not to exceed 30 rpm until the fastening's... cycles. (b) Acceptable performance. The minimum torque value required to start removal of the fastening from the installed position (minimum breakway torque) for any cycle of any test sample shall be greater...

30 CFR 7.308 - Lockwasher equivalency test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... hole and continuously and uniformly tightened at a speed not to exceed 30 rpm until the fastening's... cycles. (b) Acceptable performance. The minimum torque value required to start removal of the fastening from the installed position (minimum breakway torque) for any cycle of any test sample shall be greater...

49 CFR 393.102 - What are the minimum performance criteria for cargo securement devices and systems?

Code of Federal Regulations, 2012 CFR

2012-10-01

... chains, wire rope, steel strapping, synthetic webbing, and cordage) and other attachment or fastening..., steel strapping, synthetic webbing, and cordage) and other attachment or fastening devices used to... contained within the structure of the vehicle. Securement systems must provide a downward force equivalent...

49 CFR 238.429 - Safety appliances.

Code of Federal Regulations, 2013 CFR

2013-10-01

...-inch diameter steel pipe, 5/8-inch thickness steel, or a material of equal or greater mechanical strength. (2) All safety appliances shall be securely fastened to the car body structure with mechanical fasteners that have mechanical strength greater than or equal to that of a 1/2-inch diameter SAE grade steel...

49 CFR 393.102 - What are the minimum performance criteria for cargo securement devices and systems?

Code of Federal Regulations, 2014 CFR

2014-10-01

... chains, wire rope, steel strapping, synthetic webbing, and cordage) and other attachment or fastening..., steel strapping, synthetic webbing, and cordage) and other attachment or fastening devices used to... contained within the structure of the vehicle. Securement systems must provide a downward force equivalent...

49 CFR 393.102 - What are the minimum performance criteria for cargo securement devices and systems?

Code of Federal Regulations, 2013 CFR

2013-10-01

... chains, wire rope, steel strapping, synthetic webbing, and cordage) and other attachment or fastening..., steel strapping, synthetic webbing, and cordage) and other attachment or fastening devices used to... contained within the structure of the vehicle. Securement systems must provide a downward force equivalent...

49 CFR 238.429 - Safety appliances.

Code of Federal Regulations, 2014 CFR

2014-10-01

...-inch diameter steel pipe, 5/8-inch thickness steel, or a material of equal or greater mechanical strength. (2) All safety appliances shall be securely fastened to the car body structure with mechanical fasteners that have mechanical strength greater than or equal to that of a 1/2-inch diameter SAE grade steel...

75 FR 22424 - Avalotis Corp.; Grant of a Permanent Variance

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-28

... International, LLC, and Matrix Service Industrial Contractors, Inc.), and 71 FR 10557 (Commonwealth Dynamics... of damage or defects at all times. (b) Guide rope fastening and alignment tension. The employer must fasten one end of each guide rope securely to the overhead support, with appropriate tension applied at...

78 FR 4042 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-18

... provides an option for a high frequency eddy current inspection for cracking of the critical fastener holes... for a high frequency eddy current inspection for cracking of the critical fastener holes, and repair..., August 9, 2007)), do a high frequency eddy current (HFEC) inspection for cracking of the four critical...

Thread selection according to power characteristics during context switching on compute nodes

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

Archer, Charles J.; Blocksome, Michael A.; Randles, Amanda E.

Methods, apparatus, and products are disclosed for thread selection during context switching on a plurality of compute nodes that includes: executing, by a compute node, an application using a plurality of threads of execution, including executing one or more of the threads of execution; selecting, by the compute node from a plurality of available threads of execution for the application, a next thread of execution in dependence upon power characteristics for each of the available threads; determining, by the compute node, whether criteria for a thread context switch are satisfied; and performing, by the compute node, the thread context switchmore » if the criteria for a thread context switch are satisfied, including executing the next thread of execution.« less

Thread selection according to predefined power characteristics during context switching on compute nodes

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

None, None

Methods, apparatus, and products are disclosed for thread selection during context switching on a plurality of compute nodes that includes: executing, by a compute node, an application using a plurality of threads of execution, including executing one or more of the threads of execution; selecting, by the compute node from a plurality of available threads of execution for the application, a next thread of execution in dependence upon power characteristics for each of the available threads; determining, by the compute node, whether criteria for a thread context switch are satisfied; and performing, by the compute node, the thread context switchmore » if the criteria for a thread context switch are satisfied, including executing the next thread of execution.« less

Effects of long-term exposure on LDEF fastener assemblies

NASA Astrophysics Data System (ADS)

Spear, Steve; Dursch, Harry

1992-09-01

This presentation summarizes the Systems Special Investigations Group (SIG) findings from testing and analysis of fastener assemblies used on the Long Duration Exposure Facility (LDEF) structure, the tray mounting clamps, and by the various experimenters. The LDEF deintegration team and several experimenters noted severe fastener damage and hardware removal difficulties during post-flight activities. The System SIG has investigated all reported instances, and in all cases examined to date, the difficulties were attributed to galling during installation or post-flight removal. To date, no evidence of coldwelding was found. Correct selection of materials and lubricants as well as proper mechanical procedures is essential to ensure successful on-orbit or post-flight installation and removal of hardware.

The effect of various systems of fastening of the auxiliary reflector on the parameters of an ADE type antenna

NASA Astrophysics Data System (ADS)

Buzuev, Iu. B.; Erukhimovich, Iu. A.; Litinskii, O. A.; Timofeeva, A. A.

1980-09-01

An experimental study is presented of the influence of various systems of fastening of the auxiliary reflector on the parameters of an ADE type antenna operating at a frequency of 11 GHz. Two fastening systems are recommended: (1) a toroidal shell made of glass-reinforced polyurethane foam (gamma = 0.1-0.2 g/cu cm) with special designed inner and outer air/dielectric interfaces; and (2) the complete or partial filling of the space between the walls of the horn and the surface of the auxiliary reflector by polyurethane foam (gamma = 0.03 g/cu cm), the outer surface being glass-fiber-reinforced.

Effects of long-term exposure on LDEF fastener assemblies

NASA Technical Reports Server (NTRS)

Spear, Steve; Dursch, Harry

1992-01-01

This presentation summarizes the Systems Special Investigations Group (SIG) findings from testing and analysis of fastener assemblies used on the Long Duration Exposure Facility (LDEF) structure, the tray mounting clamps, and by the various experimenters. The LDEF deintegration team and several experimenters noted severe fastener damage and hardware removal difficulties during post-flight activities. The System SIG has investigated all reported instances, and in all cases examined to date, the difficulties were attributed to galling during installation or post-flight removal. To date, no evidence of coldwelding was found. Correct selection of materials and lubricants as well as proper mechanical procedures is essential to ensure successful on-orbit or post-flight installation and removal of hardware.

Urine cup for collection of urine from cows.

PubMed

Fellner, V; Weiss, M F; Belo, A T; Belyea, R L; Martz, F A; Orma, A H

1988-08-01

A urine cup for continuous and complete collection of urine from cows was constructed from Plastisol, cotton webb strapping, Velcro Brand touch fasteners [corrected], snap-fasteners, denim patches, weather stripping, and vacuum hose. The urine cup was made from Plastisol using a heated lead mold. It was large enough to enclose a 9 cm x 6 cm area around the vulva of a cow and was attached by strapping and Velcro Brand touch fasteners [corrected] to patches glued to the rump. Urine cups were used repeatedly and provided for long-term collection of urine from cows, eliminating the need for indwelling catheters. Applications include long-term nutrient balance, radioisotope, and metabolism studies.

A formula for evaluating colour differences for thread sewn into fabric samples

NASA Astrophysics Data System (ADS)

Steder, Thorsten

In-service rails can develop several types of structural defects due to fatigue and wear caused by rolling stock passing over them. Most rail defects will develop gradually over time thus permitting inspection engineers to detect them in time before final failure occurs. In the UK, certain types of severe rail defects such as tache ovales, require the fitting of emergency clamps and the imposing of an Emergency Speed Restriction (ESR) until the defects are removed. Acoustic emission (AE) techniques can be applied for the detection and continuous monitoring of defect growth therefore removing the need of imposing strict ESRs. The work reported herewith aims to develop a sound methodology for the application of AE in order to detect and subsequently monitor damage evolution in rails. To validate the potential of the AE technique, tests have been carried out under laboratory conditions on three and four-point bending samples manufactured from 260 grade rail steel. Further tests, simulating the background noise conditions caused by passing rolling stock have been carried out using special experimental setups. The crack growth events have been simulated using a pencil tip break..

Joint Networking Command and Control (C2) Communications Among Distributed Operations, JCAS, and Joint Fires

DTIC Science & Technology

2007-06-01

fasteners. Enviromental Spec Storage Temperature: -26 to 160 °F, Operating Temperature: -22 to 160 °F, Operating Humidity Range: 5% to 100% Non...Accessories Double 90° tongue and groove case design, with anti-tamper fasteners. Enviromental Spec Storage Temperature: -26 to 160 °F, Operating

Multiple-bolted joints in wood members : a literature review

Treesearch

Peter James Moss

1997-01-01

This study reviewed the literature on experimental and analytical research for the connection of wood members using multiple laterally loaded bolts. From this, the influence of geometric factors were ascertained, such as staggered and aligned fasteners, optimum fastener configurations, row factors and length-to-diameter bolt ratios, spacing, end and edge distances, and...

15 CFR 280.2 - Definitions used in this subpart.

Code of Federal Regulations, 2011 CFR

2011-01-01

... PROGRAMS FASTENER QUALITY General § 280.2 Definitions used in this subpart. In addition to the definitions... the United States Patent and Trademark Office. Act. The Fastener Quality Act (15 U.S.C. 5401 et seq... ISO/IEC Guides or other documents, and redesignations of those Guides or documents. Under Secretary...

15 CFR 280.2 - Definitions used in this subpart.

Code of Federal Regulations, 2010 CFR

2010-01-01

... PROGRAMS FASTENER QUALITY General § 280.2 Definitions used in this subpart. In addition to the definitions... the United States Patent and Trademark Office. Act. The Fastener Quality Act (15 U.S.C. 5401 et seq... ISO/IEC Guides or other documents, and redesignations of those Guides or documents. Under Secretary...

Astronauts Griggs and Hoffman try to fasten devices on end of RMS

NASA Technical Reports Server (NTRS)

1985-01-01

Astronauts S. David Griggs, left, and Jeffrey A. Hoffman join efforts to fasten one of two snag type devices on the end of the Canadian-built remote manipulator system (RMS) arm of the Shuttle Discovery. A partial view of the Earth's horizon can be seen behind the shuttle.

22 CFR 92.17 - Fastening of pages.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Fastening of pages. 92.17 Section 92.17 Foreign Relations DEPARTMENT OF STATE LEGAL AND RELATED SERVICES NOTARIAL AND RELATED SERVICES General Notarial... his official seal. [22 FR 10858, Dec. 27, 1957, as amended at 60 FR 51723, Oct. 3, 1995] Specific...

Fasteners. FOS: Fundamentals of Service.

ERIC Educational Resources Information Center

John Deere Co., Moline, IL.

This manual on fasteners (devices used in home and shop to hold things together) is one of a series of power mechanics texts and visual aids on operation, diagnosis, and repair. Materials provide basic information and illustrations for use by vocational students and teachers as well as shop servicemen and laymen. Seven chapters are included: (1)…

77 FR 28328 - Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-14

... loose or missing fastener, a crack, damage, or corrosion and adding an internal doubler to the aft shear... proposed actions are intended to detect a loose or missing fastener, a crack, damage, or corrosion on the T... inspection of the T/R pylon ``components and structure for obvious damage, cracks, corrosion, and security...

76 FR 58098 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-20

.... ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for all The Boeing... inspections for cracks on the area around certain fasteners of the access opening doubler on the left and... area around certain fasteners of the access opening doubler on the left and right wing center spar...

Cutting thread at flexible endoscopy.

PubMed

Gong, F; Swain, P; Kadirkamanathan, S; Hepworth, C; Laufer, J; Shelton, J; Mills, T

1996-12-01

New thread-cutting techniques were developed for use at flexible endoscopy. A guillotine was designed to follow and cut thread at the endoscope tip. A new method was developed for guiding suture cutters. Efficacy of Nd: YAG laser cutting of threads was studied. Experimental and clinical experience with thread-cutting methods is presented. A 2.4 mm diameter flexible thread-cutting guillotine was constructed featuring two lateral holes with sharp edges through which sutures to be cut are passed. Standard suture cutters were guided by backloading thread through the cutters extracorporeally. A snare cutter was constructed to retrieve objects sewn to tissue. Efficacy and speed of Nd: YAG laser in cutting twelve different threads were studied. The guillotine cut thread faster (p < 0.05) than standard suture cutters. Backloading thread shortened time taken to cut thread (p < 0.001) compared with free-hand cutting. Nd: YAG laser was ineffective in cutting uncolored threads and slower than mechanical cutters. Results of thread cutting in clinical studies using sewing machine (n = 77 cutting episodes in 21 patients), in-vivo experiments (n = 156), and postsurgical cases (n = 15 over 15 years) are presented. New thread-cutting methods are described and their efficacy demonstrated in experimental and clinical studies.

Fastener Capture Plate Technology to Contain On-Orbit Debris

NASA Technical Reports Server (NTRS)

Eisenhower, Kevin

2010-01-01

The Fastener Capture Plate technology was developed to solve the problem of capturing loose hardware and small fasteners, items that were not originally intended to be disengaged in microgravity, thus preventing them from becoming space debris. This technology was incorporated into astronaut tools designed and successfully used on NASA s Hubble Space Telescope Servicing Mission #4. The technology s ultimate benefit is that it allows a very time-efficient method for disengaging fasteners and removing hardware while minimizing the chances of losing parts or generating debris. The technology aims to simplify the manual labor required of the operator. It does so by optimizing visibility and access to the work site and minimizing the operator's need to be concerned with debris while performing the operations. It has a range of unique features that were developed to minimize task time, as well as maximize the ease and confidence of the astronaut operator. This paper describes the technology and the astronaut tools developed specifically for a complicated on-orbit repair, and it includes photographs of the hardware being used in outer space.

Influence of panel fastening on the acoustic performance of light-weight building elements: Study by sound transmission and laser scanning vibrometry

NASA Astrophysics Data System (ADS)

Roozen, N. B.; Muellner, H.; Labelle, L.; Rychtáriková, M.; Glorieux, C.

2015-06-01

Structural details and workmanship can cause considerable differences in sound insulation properties of timber frame partitions. In this study, the influence of panel fastening is investigated experimentally by means of standardized sound reduction index measurements, supported by detailed scanning laser Doppler vibrometry. In particular the effect of the number of screws used to fasten the panels to the studs, and the tightness of the screws, is studied using seven different configurations of lightweight timber frame building elements. In the frequency range from 300 to 4000 Hz, differences in the weighted sound reduction index RW as large as 10 dB were measured, suggesting that the method of fastening can have a large impact on the acoustic performance of building elements. Using the measured vibrational responses of the element, its acoustic radiation efficiency was computed numerically by means of a Rayleigh integral. The increased radiation efficiency partly explains the reduced sound reduction index. Loosening the screws, or reducing the number of screws, lowers the radiation efficiency, and significantly increases the sound reduction index of the partition.

Ergonomic analysis of fastening vibration based on ISO Standard 5349 (2001).

PubMed

Joshi, Akul; Leu, Ming; Murray, Susan

2012-11-01

Hand-held power tools used for fastening operations exert high dynamic forces on the operator's hand-arm, potentially causing injuries to the operator in the long run. This paper presents a study that analyzed the vibrations exerted by two hand-held power tools used for fastening operations with the operating exhibiting different postures. The two pneumatic tools, a right-angled nut-runner and an offset pistol-grip, are used to install shearing-type fasteners. A tri-axial accelerometer is used to measure the tool's vibration. The position and orientation of the transducer mounted on the tool follows the ISO-5349 Standard. The measured vibration data is used to compare the two power tools at different operating postures. The data analysis determines the number of years required to reach a 10% probability of developing finger blanching. The results indicate that the pistol-grip tool induces more vibration in the hand-arm than the right-angled nut-runner and that the vibrations exerted on the hand-arm vary for different postures. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Tool Removes Coil-Spring Thread Inserts

NASA Technical Reports Server (NTRS)

Collins, Gerald J., Jr.; Swenson, Gary J.; Mcclellan, J. Scott

1991-01-01

Tool removes coil-spring thread inserts from threaded holes. Threads into hole, pries insert loose, grips insert, then pulls insert to thread it out of hole. Effects essentially reverse of insertion process to ease removal and avoid further damage to threaded inner surface of hole.

The Design of Mechanically Compatible Fasteners for Human Mandible Reconstruction

NASA Technical Reports Server (NTRS)

Roberts, Jack C.; Ecker, John A.; Biermann, Paul J.

1993-01-01

Mechanically compatible fasteners for use with thin or weakened bone sections in the human mandible are being developed to help reduce large strain discontinuities across the bone/implant interface. Materials being considered for these fasteners are a polyetherertherketone (PEEK) resin with continuous quartz or carbon fiber for the screw. The screws were designed to have a shear strength equivalent to that of compact/trabecular bone and to be used with a conventional nut, nut plate, or an expandable shank/blind nut made of a ceramic filled polymer. Physical and finite element models of the mandible were developed in order to help select the best material fastener design. The models replicate the softer inner core of trabecular bone and the hard outer shell of compact bone. The inner core of the physical model consisted of an expanding foam and the hard outer shell consisted of ceramic particles in an epoxy matrix. This model has some of the cutting and drilling attributes of bone and may be appropriate as an educational tool for surgeons and medical students. The finite element model was exercised to establish boundary conditions consistent with the stress profiles associated with mandible bite forces and muscle loads. Work is continuing to compare stress/strain profiles of a reconstructed mandible with the results from the finite element model. When optimized, these design and fastening techniques may be applicable, not only to other skeletal structures, but to any composite structure.

Thread gauge for measuring thread pitch diameters

DOEpatents

Brewster, A.L.

1985-11-19

A thread gauge which attaches to a vernier caliper to measure the thread pitch diameter of both externally threaded and internally threaded parts is disclosed. A pair of anvils are externally threaded with threads having the same pitch as those of the threaded part. Each anvil is mounted on a stem having a ball on which the anvil can rotate to properly mate with the parts to which the anvils are applied. The stems are detachably secured to the caliper blades by attachment collars having keyhole openings for receiving the stems and caliper blades. A set screw is used to secure each collar on its caliper blade. 2 figs.

Thread gauge for measuring thread pitch diameters

DOEpatents

Brewster, Albert L.

1985-01-01

A thread gauge which attaches to a vernier caliper to measure the thread pitch diameter of both externally threaded and internally threaded parts. A pair of anvils are externally threaded with threads having the same pitch as those of the threaded part. Each anvil is mounted on a stem having a ball on which the anvil can rotate to properly mate with the parts to which the anvils are applied. The stems are detachably secured to the caliper blades by attachment collars having keyhole openings for receiving the stems and caliper blades. A set screw is used to secure each collar on its caliper blade.

75 FR 7945 - Airworthiness Directives; Augustair, Inc. Models 2150, 2150A, and 2180 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-23

... inspect the vertical stabilizer front spar for cracks and loose fasteners, repair any cracks and loose fasteners found, and reinforce the vertical stabilizer spar regardless if cracks are found. This AD results from six reports of airplanes with a cracked vertical stabilizer front spar. We are issuing this AD to...

78 FR 70214 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-25

... cracks at the shear tie end fastener locations of the fuselage frames, and repair of cracks if necessary... fastener locations of the fuselage frames, and repair of cracks if necessary. The NPRM also proposed to... the frame shear ties, as stated in the NPRM (78 FR 33012, June 3, 2013). We agree with the request and...

Detection of cracks beneath rivet heads via pulsed eddy current technique

NASA Astrophysics Data System (ADS)

Giguère, J. S. R.; Lepine, B. A.; Dubois, J. M. S.

2002-05-01

Improving the detectability of fatigue cracks under installed fasteners is one of the many goals of the aging aircraft nondestructive evaluation (NDE) community. The pulsed eddy current offers new capabilities to address this requirement. The aim of the paper is to evaluate the potential of this technique for detecting and quantifying notches under installed fasteners.

Development of the weldbond process for joining titanium

NASA Technical Reports Server (NTRS)

Fields, D.

1972-01-01

High quality resistance spot welds were produced by welding through epoxy adhesive on titanium alloys. Weldbond joints were consistently stronger than those of either mechanical fasteners, structural adhesive bonds, or mechanical fasteners with adhesive at the joint interface. Weldbond joints and/or spot weld joints showed superior strength at all temperature ranges as compared to other joints tested.

75 FR 27969 - Airworthiness Directives; The Boeing Company Model 737-100 and -200 Series Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-19

... cracking and damaged fasteners of certain fuselage frames and stub beams, and corrective actions if... the inboard chord fastener hole of the frame at body station 639, stringer S-16, and corrective... inspections for the repaired or modified frame only. For airplanes on which the modification or repair is done...

Comparing the Methodologies in ASTM G198: Is There an Easy Way Out?

Treesearch

Samuel L. Zelinka

2013-01-01

ASTM(1) G198, Standard test method for determining the relative corrosion performance of driven fasteners in contact with treated wood, was accepted by consensus and published in 2011. The method has two different exposure conditions for determining fastener corrosion performance in treated wood. The first method places the wood and embedded...

Simplified analysis of timber rivet connections

Treesearch

Douglas C. Stahl; Marshall. Begel; Ronald W. Wolfe

2000-01-01

Timber rivets, fasteners for glulam and heavy timber construction, have been used in Canada for about thirty years and recently were adopted by the U.S. National Design Specification for Wood Construction (NDS). Rivet connections can exhibit two failure modes, one of which is fundamentally different from those of other dowel fasteners. Failure can occur when a volume...

77 FR 68061 - Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-15

...) pylon for a loose or missing fastener, a crack, damage, or corrosion and adding an internal doubler to... actions are intended to detect a loose or missing fastener, a crack, damage, or corrosion on the T/R pylon..., a crack, damage, or corrosion, and repairing or replacing the T/R pylon if any of these conditions...

Mechanical connection for a tubular assembly

DOEpatents

Grover, J.M.

1984-09-12

Disclosed is a mechanical connection assembly for connecting two telescopically related parts together in a fluidtight relation. The system uses snap-in fasteners having flexible barbed tangs which are snapped into receiving holes formed in the parts being attached together. A locking pin can be inserted into a central aperture through the snap-in fastener to secure the fastener in the receiving holes. The system also includes a seal having sealing surfaces at least one of which is formed at an angle inclined relative to a true vertical. a metallic sealing element is interposed between the sealing surfaces. The geometry of the sealing surfaces is capable of compensating for the differential thermal growth rates occurring when the two parts are made from dissimilar metals.

78 FR 76815 - Steel Threaded Rod From India: Preliminary Affirmative Countervailing Duty Determination and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-19

... DEPARTMENT OF COMMERCE International Trade Administration [C-533-856] Steel Threaded Rod From... exporters of steel threaded rod from India. The period of investigation (``POI'') is January 1, 2012... this investigation is steel threaded rod. Steel threaded rod is certain threaded rod, bar, or studs, of...

Online discussion groups for bulimia nervosa: an inductive approach to Internet-based communication between patients.

PubMed

Wesemann, Dorette; Grunwald, Martin

2008-09-01

Online discussion forums are often used by people with eating disorders. This study analyses 2,072 threads containing a total of 14,903 postings from an unmoderated German "prorecovery" forum for persons suffering from bulimia nervosa (www.ab-server.de) during the period from October 2004 to May 2006. The threads were inductively analyzed for underlying structural types, and the various types found were then analyzed for differences in temporal and quantitative parameters. Communication in the online discussion forum occurred in three types of thread: (1) problem-oriented threads (78.8% of threads), (2) communication-oriented threads (15.3% of threads), and (3) metacommunication threads (2.6% of threads). Metacommunication threads contained significantly more postings than problem-oriented and communication-oriented threads, and they were viewed significantly more often. Moreover, there are temporal differences between the structural types. Topics relating to active management of the disorder receive great attention in prorecovery forums. (c) 2008 by Wiley Periodicals, Inc.

Two years' outcome of thread lifting with absorbable barbed PDO threads: Innovative score for objective and subjective assessment.

PubMed

Ali, Yasser Helmy

2018-02-01

Thread-lifting rejuvenation procedures have evolved again, with the development of absorbable threads. Although they have gained popularity among plastic surgeons and dermatologists, very few articles have been written in literature about absorbable threads. This study aims to evaluate two years' outcome of thread lifting using absorbable barbed threads for facial rejuvenation. Prospective comparative stud both objectively and subjectively and follow-up assessment for 24 months. Thread lifting for face rejuvenation has significant long-lasting effects that include skin lifting from 3-10 mm and high degree of patients' satisfaction with less incidence rate of complications, about 4.8%. Augmented results are obtained when thread lifting is combined with other lifting and rejuvenation modalities. Significant facial rejuvenation is achieved by thread lifting and highly augmented results are observed when they are combined with Botox, fillers, and/or platelet rich plasma (PRP) rejuvenations.

Thread gauge for tapered threads

DOEpatents

Brewster, Albert L.

1994-01-11

The thread gauge permits the user to determine the pitch diameter of tapered threads at the intersection of the pitch cone and the end face of the object being measured. A pair of opposed anvils having lines of threads which match the configuration and taper of the threads on the part being measured are brought into meshing engagement with the threads on opposite sides of the part. The anvils are located linearly into their proper positions by stop fingers on the anvils that are brought into abutting engagement with the end face of the part. This places predetermined reference points of the pitch cone of the thread anvils in registration with corresponding points on the end face of the part being measured, resulting in an accurate determination of the pitch diameter at that location. The thread anvils can be arranged for measuring either internal or external threads.

Thread gauge for tapered threads

DOEpatents

Brewster, A.L.

1994-01-11

The thread gauge permits the user to determine the pitch diameter of tapered threads at the intersection of the pitch cone and the end face of the object being measured. A pair of opposed anvils having lines of threads which match the configuration and taper of the threads on the part being measured are brought into meshing engagement with the threads on opposite sides of the part. The anvils are located linearly into their proper positions by stop fingers on the anvils that are brought into abutting engagement with the end face of the part. This places predetermined reference points of the pitch cone of the thread anvils in registration with corresponding points on the end face of the part being measured, resulting in an accurate determination of the pitch diameter at that location. The thread anvils can be arranged for measuring either internal or external threads. 13 figures.

CNT coated thread micro-electro-mechanical system for finger proprioception sensing

NASA Astrophysics Data System (ADS)

Shafi, A. A.; Wicaksono, D. H. B.

2017-04-01

In this paper, we aim to fabricate cotton thread based sensor for proprioceptive application. Cotton threads are utilized as the structural component of flexible sensors. The thread is coated with multi-walled carbon nanotube (MWCNT) dispersion by using facile conventional dipping-drying method. The electrical characterization of the coated thread found that the resistance per meter of the coated thread decreased with increasing the number of dipping. The CNT coated thread sensor works based on piezoresistive theory in which the resistance of the coated thread changes when force is applied. This thread sensor is sewed on glove at the index finger between middle and proximal phalanx parts and the resistance change is measured upon grasping mechanism. The thread based microelectromechanical system (MEMS) enables the flexible sensor to easily fit perfectly on the finger joint and gives reliable response as proprioceptive sensing.

Novel use of a percutaneous endoscopic gastrostomy tube fastener for securing silicone tracheal stents in patients with benign proximal airway obstruction.

PubMed

Musani, Ali I; Jensen, Kurt; Mitchell, John D; Weyant, Michael; Garces, Katherine; Hsia, David

2012-04-01

Benign tracheal obstruction occurs for a variety of reasons. Bronchoscopic intervention includes silicone stent placement, which effectively maintains airway patency. Stent migration is a common complication, particularly when placed in the proximal trachea. We used a novel technique of securing tracheal stents with a percutaneous endoscopic gastrostomy tube fastener (PEG-TF) to prevent stent migration. The purpose of this study was to determine the feasibility of securing silicone stents in the proximal trachea with PEG-TF. Silicone stents were placed under general anesthesia by rigid bronchoscopy in 7 consecutive patients with inoperable benign proximal tracheal obstruction. PEG-TFs were placed under sterile conditions with direct bronchoscopic visualization. A needle was inserted through the anterior neck and silicone stent wall allowing stylet introduction of a T-fastener into the interior of the stent. The T-fastener was secured externally by a metal clamp and cotton pledget at the surface of the neck. Patients had routine outpatient follow-up and covered the external portion of the PEG-TF with a waterproof dressing when showering. All 7 PEG-TFs were placed without complications. The PEG-TFs were left in for 1 to 25 weeks. Complications of the PEG-TF included localized cellulitis and suture breakage. No stent migration occurred while the fastener was in place. Two stents were removed within 2 weeks due to patient's difficulty tolerating the stent. Securing silicone stents in the proximal trachea is feasible and may prevent stent migration, but further study and possible modification of the PEG-TF device are needed.

Design of internal screw thread measuring device based on the Three-Line method principle

NASA Astrophysics Data System (ADS)

Hu, Dachao; Chen, Jianguo

2010-08-01

In accordance with the principle of Three-Line, this paper analyze the correlation of every main parameter of internal screw thread, and then designed a device to measure the main parameters of internal screw thread. Internal thread parameters, such as the pitch diameter, thread angle and screw-pitch of common screw thread, terraced screw thread, zigzag screw thread were obtained through calculation and measurement. The practical applications have proved that this device is convenience to use, and the measurements have a high accuracy. Meanwhile, the application for the patent of invention has been accepted by the Patent Office (Filing number: 200710044081.5).

The effect of moisture content on the corrosion of fasteners embedded in wood subjected to alkaline copper quaternary treatment

Treesearch

Samuel L. Zelinka; Samuel V. Glass; Dominique Derome

2014-01-01

This paper characterizes the corrosion rate of embedded fasteners as a function of wood moisture content using gravimetric and electrochemical measurements. The results indicated that the corrosion rate increased with moisture content before reaching a plateau. The phases present in the corrosion products, as analyzed using X-ray diffraction, are generally consistent...

Mechanism of Transport Through Wood Cell Wall Polymers

Treesearch

Joseph E. Jakes; Nayomi Plaza; Donald S. Stone; Christopher G. Hunt; Samuel V. Glass; Samuel L. Zelinka

2013-01-01

The movement of chemicals through wood is necessary for decay and fastener corrosion to occur in forest products. However, the mechanism responsible for the onset of fastener corrosion and decay in wood is not known. The onset occurs before the formation of free water in wood cavities and aqueous chemical transport would be possible. Here, we propose that the onset...

Electrochemical impedance spectroscopy (EIS) as a tool for measuring corrosion of polymer-coated fasteners used in treated wood

Treesearch

Samuel L. Zelinka; Lorraine Ortiz-Candelaria; Donald S. Stone; Douglas R. Rammer

2009-01-01

Currently, many of the polymer-coated fasteners on the market are designed for improved corrosion performance in treated wood; yet, there is no way to evaluate their corrosion performance. In this study, a common technique for measuring the corrosion performance of polymer-coated metals, electrochemical impedance spectroscopy (EIS), was used to evaluate commercial...

76 FR 72858 - Airworthiness Directives; The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-28

... of the Station (STA) 348.2 frame to detect cracking under the stop fittings and intercostal flanges... reports of cracking of the STA 348.2 frame above the two outboard fasteners attaching the frame inner... of missing fasteners in the STA 348.2 frame inner chord. This proposed AD would require additional...

75 FR 39185 - Airworthiness Directives; The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-08

... and torque checks of the hanger fittings and strut forward bulkhead of the forward engine mount and... requires repetitive inspections and torque checks of the hanger fittings and strut forward bulkhead of the... corrective actions are replacing the fasteners; removing loose fasteners; tightening all Group A [[Page 39187...

19 CFR 24.13a - Car, compartment, and package seals; and fastenings; standards; acceptance by Customs.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 1 2014-04-01 2014-04-01 false Car, compartment, and package seals; and... PROCEDURE § 24.13a Car, compartment, and package seals; and fastenings; standards; acceptance by Customs. (a... identification number on the seal. (2) If the seal is to be used by private industry (i.e., a shipper...

19 CFR 24.13a - Car, compartment, and package seals; and fastenings; standards; acceptance by Customs.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 1 2013-04-01 2013-04-01 false Car, compartment, and package seals; and... PROCEDURE § 24.13a Car, compartment, and package seals; and fastenings; standards; acceptance by Customs. (a... identification number on the seal. (2) If the seal is to be used by private industry (i.e., a shipper...

19 CFR 24.13a - Car, compartment, and package seals; and fastenings; standards; acceptance by Customs.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 1 2012-04-01 2012-04-01 false Car, compartment, and package seals; and... PROCEDURE § 24.13a Car, compartment, and package seals; and fastenings; standards; acceptance by Customs. (a... identification number on the seal. (2) If the seal is to be used by private industry (i.e., a shipper...

Transpiration-Cooled Spacecraft-Insulation-Repair Fasteners

NASA Technical Reports Server (NTRS)

Camarda, Charles J.; Pettit, Donald R.; Glass, David; Scotti, Stephen J.; Vaughn, Wallace Lee; Rawal, Suraj

2012-01-01

Transpiration-cooled fasteners are proposed that operate like an open-loop heat pipe (self-tapping screws, bolts, and spikes) for use in on-orbit repair of thermal- insulation of a space shuttle or other spacecraft. By limiting the temperature rise of such a fastener and of the adjacent repair material and thermal protection system, the transpiration cooling would contribute to the ability of the repair to retain its strength and integrity in the high-heat-flux, oxidizing environment of reentry into the atmosphere of the Earth. A typical fastener according to the proposal would include a hollow refractory-metal, refractory-composite, or ceramic screw or bolt, the central cavity of which would be occupied by a porous refractory- metal or ceramic plug that would act as both a reservoir and a wick for a transpirant liquid. The plug dimensions, the plug material, and the sizes of the pores would be chosen in conjunction with the transpirant liquid so that (1) capillary pumping could be relied upon to transport the liquid to the heated surface, where the liquid would be vaporized, and (2) the amount of liquid would suffice for protecting against the anticipated heat flux and integrated heat load.

Thread angle dependency on flame spread shape over kenaf/polyester combined fabric

NASA Astrophysics Data System (ADS)

Azahari Razali, Mohd; Sapit, Azwan; Nizam Mohammed, Akmal; Nor Anuar Mohamad, Md; Nordin, Normayati; Sadikin, Azmahani; Faisal Hushim, Mohd; Jaat, Norrizam; Khalid, Amir

2017-09-01

Understanding flame spread behavior is crucial to Fire Safety Engineering. It is noted that the natural fiber exhibits different flame spread behavior than the one of the synthetic fiber. This different may influences the flame spread behavior over combined fabric. There is a research has been done to examined the flame spread behavior over kenaf/polyester fabric. It is seen that the flame spread shape is dependent on the thread angle dependency. However, the explanation of this phenomenon is not described in detail in that research. In this study, explanation about this phenomenon is given in detail. Results show that the flame spread shape is dependent on the position of synthetic thread. For thread angle, θ = 0°, the polyester thread is breaking when the flame approach to the thread and the kenaf thread tends to move to the breaking direction. This behavior produces flame to be ‘V’ shape. However, for thread angle, θ = 90°, the polyester thread melts while the kenaf thread decomposed and burned. At this angle, the distance between kenaf threads remains constant as flame approaches.

The effect of thread pattern upon implant osseointegration.

PubMed

Abuhussein, Heba; Pagni, Giorgio; Rebaudi, Alberto; Wang, Hom-Lay

2010-02-01

Implant design features such as macro- and micro-design may influence overall implant success. Limited information is currently available. Therefore, it is the purpose of this paper to examine these factors such as thread pitch, thread geometry, helix angle, thread depth and width as well as implant crestal module may affect implant stability. A literature search was conducted using MEDLINE to identify studies, from simulated laboratory models, animal, to human, related to this topic using the keywords of implant thread, implant macrodesign, thread pitch, thread geometry, helix angle, thread depth, thread width and implant crestal module. The results showed how thread geometry affects the distribution of stress forces around the implant. A decreased thread pitch may positively influence implant stability. Excess helix angles in spite of a faster insertion may jeopardize the ability of implants to sustain axial load. Deeper threads seem to have an important effect on the stabilization in poorer bone quality situations. The addition of threads or microthreads up to the crestal module of an implant might provide a potential positive contribution on bone-to to-implant contact as well as on the preservation of marginal bone; nonetheless this remains to be determined. Appraising the current literature on this subject and combining existing data to verify the presence of any association between the selected characteristics may be critical in the achievement of overall implant success.

Space fabrication demonstration system. [beam builder and induction fastening

NASA Technical Reports Server (NTRS)

1980-01-01

The development effort on the composite beam cap fabricator was completed within cost and close to abbreviated goals. The design and analysis of flight weight primary and secondary beam builder structures proceeded satisfactorily but remains curtailed until further funding is made available to complete the work. The induction fastening effort remains within cost and schedule constraints. Tests of the LARC prototype induction welder is continuing in an instrumented test stand comprised of a Dumore drill press (air over oil feed for variable applied loads) and a dynamometer to measure actual welding loads. Continued testing shows that the interface screening must be well impregnated with resin to ensure proper flow when bonding graphite-acrylic lap shear samples. Specimens prepared from 0.030 inch thick graphite-polyethersulfone are also available for future induction fastening evaluation.

Method for molding threads in graphite panels

DOEpatents

Short, W.W.; Spencer, C.

1994-11-29

A graphite panel with a hole having a damaged thread is repaired by drilling the hole to remove all of the thread and making a new hole of larger diameter. A bolt with a lubricated thread is placed in the new hole and the hole is packed with graphite cement to fill the hole and the thread on the bolt. The graphite cement is cured, and the bolt is unscrewed therefrom to leave a thread in the cement which is at least as strong as that of the original thread. 8 figures.

The measure method of internal screw thread and the measure device design

NASA Astrophysics Data System (ADS)

Hu, Dachao; Chen, Jianguo

2008-12-01

In accordance with the principle of Three-Line, this paper analyzed the correlation of every main parameter of internal screw thread, and then designed a device to measure the main parameters of internal screw thread. Basis on the measured value and corresponding formula calculation, we can get the internal thread parameters, such as the pitch diameter, thread angle and screw-pitch of common screw thread, terraced screw thread, zigzag screw thread and some else. The practical application has proved that this operation of this device is convenience, and the measured dates have a high accuracy. Meanwhile, the application of this device's patent of invention is accepted by the Patent Office. (The filing number: 200710044081.5)

Insertion tube methods and apparatus

DOEpatents

Casper, William L.; Clark, Don T.; Grover, Blair K.; Mathewson, Rodney O.; Seymour, Craig A.

2007-02-20

A drill string comprises a first drill string member having a male end; and a second drill string member having a female end configured to be joined to the male end of the first drill string member, the male end having a threaded portion including generally square threads, the male end having a non-threaded extension portion coaxial with the threaded portion, and the male end further having a bearing surface, the female end having a female threaded portion having corresponding female threads, the female end having a non-threaded extension portion coaxial with the female threaded portion, and the female end having a bearing surface. Installation methods, including methods of installing instrumented probes are also provided.

Subsurface drill string

DOEpatents

Casper, William L [Rigby, ID; Clark, Don T [Idaho Falls, ID; Grover, Blair K [Idaho Falls, ID; Mathewson, Rodney O [Idaho Falls, ID; Seymour, Craig A [Idaho Falls, ID

2008-10-07

A drill string comprises a first drill string member having a male end; and a second drill string member having a female end configured to be joined to the male end of the first drill string member, the male end having a threaded portion including generally square threads, the male end having a non-threaded extension portion coaxial with the threaded portion, and the male end further having a bearing surface, the female end having a female threaded portion having corresponding female threads, the female end having a non-threaded extension portion coaxial with the female threaded portion, and the female end having a bearing surface. Installation methods, including methods of installing instrumented probes are also provided.

CMS event processing multi-core efficiency status

NASA Astrophysics Data System (ADS)

Jones, C. D.; CMS Collaboration

2017-10-01

In 2015, CMS was the first LHC experiment to begin using a multi-threaded framework for doing event processing. This new framework utilizes Intel’s Thread Building Block library to manage concurrency via a task based processing model. During the 2015 LHC run period, CMS only ran reconstruction jobs using multiple threads because only those jobs were sufficiently thread efficient. Recent work now allows simulation and digitization to be thread efficient. In addition, during 2015 the multi-threaded framework could run events in parallel but could only use one thread per event. Work done in 2016 now allows multiple threads to be used while processing one event. In this presentation we will show how these recent changes have improved CMS’s overall threading and memory efficiency and we will discuss work to be done to further increase those efficiencies.

Multi-threading: A new dimension to massively parallel scientific computation

NASA Astrophysics Data System (ADS)

Nielsen, Ida M. B.; Janssen, Curtis L.

2000-06-01

Multi-threading is becoming widely available for Unix-like operating systems, and the application of multi-threading opens new ways for performing parallel computations with greater efficiency. We here briefly discuss the principles of multi-threading and illustrate the application of multi-threading for a massively parallel direct four-index transformation of electron repulsion integrals. Finally, other potential applications of multi-threading in scientific computing are outlined.

Development of failure mechanisms for fasteners in the United States

Treesearch

Douglas R. Rammer; Philip Line

2006-01-01

In the 2001 National Design Specifications® for Wood Construction (NDS), Appendix E was added to explicitly address wood failure mechanisms that may occur in fasteners. One approach to estimate design capacities for net section, row tear out, and group tear failure mechanisms is presented in Appendix E of the 2001 NDS. Since the 2001 NDS, efforts are being untaken to...

Exposure test of fasteners in preservative-treated wood

Treesearch

Samuel L. Zelinka; Douglas R. Rammer

2006-01-01

This study examined nails and screws exposed to ACQ-treated wood for up to 12 months in a controlled environment. The environment (27ºC, 100% relative humidity) was chosen so that comparisons could be made with previous exposure tests run using CCA-treated wood in the same environment. Five types of fasteners (common 8d nail, hot-dipped galvanized 8d nail, 4d aluminum...

Exposure testing of fasteners in preservative treated wood : gravimetric corrosion rates and corrosion product analyses

Treesearch

Samuel L. Zelinka; Rebecca J. Sichel; Donald S. Stone

2010-01-01

Research was conducted to determine the corrosion rates of metals in preservative treated wood and also understand the mechanism of metal corrosion in treated wood. Steel and hot-dip galvanized steel fasteners were embedded in wood treated with one of six preservative treatments and exposed to 27oC at 100% relative humidity for 1 year. The...

Corrosion Behavior of Sacrificial Coatings on Grade 10.9 Fasteners for Multimetal Armor Applications

DTIC Science & Technology

2013-08-01

hexavalent chromium , immersion, magniplate, trivalent chromium (TCP), bolts nonchromate, hexavalent chrome, grade 10.9 fasteners, bolt-on armor...for Testing and Materials (ASTM) B633 (4) electroplated zinc with hexavalent chromium conversion coating 2. Trivalent Chromium Process (TCP): ASTM...B633 (4) electroplated zinc with trivalent chromium conversion coating 3. AlumiPlate: Process details, entire surface electroplated with aluminum (Al

The use of electrochemical impedance spectroscopy (EIS) to measure the corrosion of metals in contact with wood

Treesearch

Samuel L. Zelinka; Douglas R. Rammer

2005-01-01

Although preservative treatments prolong the life of wood, they can also contribute to the corrosion of fasteners. The corrosion of fasteners merits further study because it can affect the long-term durability of structures and fundamental knowledge of corrosion in wood is limited. The goal of this study is to determine the viability of electrochemical impedance...

From laboratory corrosion tests to a corrosion lifetime for wood fasteners : progress and challenges

Treesearch

Samuel L. Zelinka; Dominique Derome; Samuel V. Glass

2010-01-01

Determining a “corrosion-lifetime” for fasteners embedded in wood treated with recently adopted preservative systems depends upon successfully relating results of laboratory tests to in-service conditions. In contrast to laboratory tests where metal is embedded in wood at constant temperature and moisture content, the in-service temperature and moisture content of wood...

Improved Screw-Thread Lock

NASA Technical Reports Server (NTRS)

Macmartin, Malcolm

1995-01-01

Improved screw-thread lock engaged after screw tightened in nut or other mating threaded part. Device does not release contaminating material during tightening of screw. Includes pellet of soft material encased in screw and retained by pin. Hammer blow on pin extrudes pellet into slot, engaging threads in threaded hole or in nut.

Method for molding threads in graphite panels

DOEpatents

Short, William W.; Spencer, Cecil

1994-01-01

A graphite panel (10) with a hole (11) having a damaged thread (12) is repaired by drilling the hole (11) to remove all of the thread and make a new hole (13) of larger diameter. A bolt (14) with a lubricated thread (17) is placed in the new hole (13) and the hole (13) is packed with graphite cement (16) to fill the hole and the thread on the bolt. The graphite cement (16) is cured, and the bolt is unscrewed therefrom to leave a thread (20) in the cement (16) which is at least as strong as that of the original thread (12).

Method for Estimating Thread Strength Reduction of Damaged Parent Holes with Inserts

NASA Technical Reports Server (NTRS)

Johnson, David L.; Stratton, Troy C.

2005-01-01

During normal assembly and disassembly of bolted-joint components, thread damage and/or deformation may occur. If threads are overloaded, thread damage/deformation can also be anticipated. Typical inspection techniques (e.g. using GO-NO GO gages) may not provide adequate visibility of the extent of thread damage. More detailed inspection techniques have provided actual pitch-diameter profiles of damaged-hardware holes. A method to predict the reduction in thread shear-out capacity of damaged threaded holes has been developed. This method was based on testing and analytical modeling. Test samples were machined to simulate damaged holes in the hardware of interest. Test samples containing pristine parent-holes were also manufactured from the same bar-stock material to provide baseline results for comparison purposes. After the particular parent-hole thread profile was machined into each sample a helical insert was installed into the threaded hole. These samples were tested in a specially designed fixture to determine the maximum load required to shear out the parent threads. It was determined from the pristine-hole samples that, for the specific material tested, each individual thread could resist an average load of 3980 pounds. The shear-out loads of the holes having modified pitch diameters were compared to the ultimate loads of the specimens with pristine holes. An equivalent number of missing helical coil threads was then determined based on the ratio of shear-out loads for each thread configuration. These data were compared with the results from a finite element model (FEM). The model gave insights into the ability of the thread loads to redistribute for both pristine and simulated damage configurations. In this case, it was determined that the overall potential reduction in thread load-carrying capability in the hardware of interest was equal to having up to three fewer threads in the hole that bolt threads could engage. One- half of this potential reduction was due to local pitch-diameter variations and the other half was due to overall pitch-diameter enlargement beyond Class 2 fit. This result was important in that the thread shear capacity for this particular hardware design was the limiting structural capability. The details of the method development, including the supporting testing, data reduction and analytical model results comparison will be discussed hereafter.

[Skin graft combined with thorax wire fastening for repairing postoperative coloboma After resection of chest back giant nevus].

PubMed

Zhao, Weimin; Dai, Tao; Yuan, Depin; Zhang, Gongbao

2011-11-01

To observe the effectiveness of skin graft combined with thorax wire fastening for repairing postoperative coloboma after resection of chest back giant nevus. Between June 2007 and October 2010, 17 cases of chest back giant nevus were treated. There were 7 males and 10 females, aged from 3 years and 6 months to 15 years (mean, 8 years). The size of giant nevus was 20 cm x 12 cm to 60 cm x 50 cm. Two cases of them were ever treated by laser, while the others were never treated. The check before operation showed ulcer of the skin and effusion in 2 cases, hard skin in 3 cases, hair growth in 7 cases, and normal in 5 cases. Five cases had serious itch. After giant nevus was cut off, thorax wire was fastened to reduce the wound area, and then the intermediate split thickness skin graft of thigh was used to repair the wound. Comprehensive anti-scar treatment was given postoperatively. The wound size was (2 110.74 +/- 725.69) cm2 after resection of giant nevus, and was (1 624.94 +/- 560.57) cm2 after thorax wire fastening, showing significant difference (t = 9.006, P = 0.001). All the grafting skin survived; the incision and wound at donor site healed by first intention. The patients were followed up 6 months to 2 years (mean, 13 months). No scar proliferation or contracture occurred. The skin color and elasticity were similar to the normal skin; the nipple, navel, and other local apparatus were not shifted after operation. It can reduce donor site of skin and postoperative scar, and achieve satisfactory appearance to cover the wound by skin graft combined with thorax wire fastening after chest back giant nevus was cut off.

Stress analysis method for clearance-fit joints with bearing-bypass loads

NASA Technical Reports Server (NTRS)

Naik, R. A.; Crews, J. H., Jr.

1989-01-01

Within a multi-fastener joint, fastener holes may be subjected to the combined effects of bearing loads and loads that bypass the hole to be reacted elsewhere in the joint. The analysis of a joint subjected to search combined bearing and bypass loads is complicated by the usual clearance between the hole and the fastener. A simple analysis method for such clearance-fit joints subjected to bearing-bypass loading has been developed in the present study. It uses an inverse formulation with a linear elastic finite-element analysis. Conditions along the bolt-hole contact arc are specified by displacement constraint equations. The present method is simple to apply and can be implemented with most general purpose finite-element programs since it does not use complicated iterative-incremental procedures. The method was used to study the effects of bearing-bypass loading on bolt-hole contact angles and local stresses. In this study, a rigid, frictionless bolt was used with a plate having the properties of a quasi-isotropic graphite/epoxy laminate. Results showed that the contact angle as well as the peak stresses around the hole and their locations were strongly influenced by the ratio of bearing and bypass loads. For single contact, tension and compression bearing-bypass loading had opposite effects on the contact angle. For some compressive bearing-bypass loads, the hole tended to close on the fastener leading to dual contact. It was shown that dual contact reduces the stress concentration at the fastener and would, therefore, increase joint strength in compression. The results illustrate the general importance of accounting for bolt-hole clearance and contact to accurately compute local bolt-hole stresses for combined bearings and bypass loading.

The research and development of the non-contact detection of the tubing internal thread with a line structured light

NASA Astrophysics Data System (ADS)

Hu, Yuanyuan; Xu, Yingying; Hao, Qun; Hu, Yao

2013-12-01

The tubing internal thread plays an irreplaceable role in the petroleum equipment. The unqualified tubing can directly lead to leakage, slippage and bring huge losses for oil industry. For the purpose of improving efficiency and precision of tubing internal thread detection, we develop a new non-contact tubing internal thread measurement system based on the laser triangulation principle. Firstly, considering that the tubing thread had a small diameter and relatively smooth surface, we built a set of optical system with a line structured light to irradiate the internal thread surface and obtain an image which contains the internal thread profile information through photoelectric sensor. Secondly, image processing techniques were used to do the edge detection of the internal thread from the obtained image. One key method was the sub-pixel technique which greatly improved the detection accuracy under the same hardware conditions. Finally, we restored the real internal thread contour information on the basis of laser triangulation method and calculated tubing thread parameters such as the pitch, taper and tooth type angle. In this system, the profile of several thread teeth can be obtained at the same time. Compared with other existing scanning methods using point light and stepper motor, this system greatly improves the detection efficiency. Experiment results indicate that this system can achieve the high precision and non-contact measurement of the tubing internal thread.

Measurement of Sound Speed in Thread

NASA Astrophysics Data System (ADS)

Saito, Shigemi; Shibata, Yasuhiro; Ichiki, Akira; Miyazaki, Akiho

2006-05-01

By employing thin wires, human hairs and threads, the measurement of sound speed in a thread whose diameter is smaller than 0.2 mm has been attempted. Preparing two cylindrical ceramic transducers with a 300 kHz resonance frequency, a perforated glass bead to be knotted by a sample thread is bonded to the center of the end surface of each transducer. After connecting these transducers with a sample thread, a receiving transducer is attached at a ceiling so as to hang another transmitting transducer with the thread. A glass bead is bonded to another end surface of the transmitting transducer so that tension, varied with a hanged plumb, can be applied to the sample thread. The time delay of the received signal relative to the transmitting pulse is measured while gradually shortening the thread. Sound speed is determined by the proportionality of time delay with thread length. Although the measured values for metallic wires are somewhat different from the values derived from the density and Young’s modulus cited in references, they are reproducible. The sound speed for human hairs of over twenty samples, which varies between 2000 and 2500 m/s, seems to depend on hair quality. Sound speed in a cotton thread is found to approach a constant value under large tension. An advanced measurement system available for uncut threads is also presented, where semi cylindrical transducers pinch the thread.

78 FR 79670 - Steel Threaded Rod From Thailand: Preliminary Determination of Sales at Less Than Fair Value and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-31

... DEPARTMENT OF COMMERCE International Trade Administration [A-549-831] Steel Threaded Rod From... ``Department'') preliminarily determines that steel threaded rod from Thailand is being, or is likely to be... Investigation The merchandise covered by this investigation is steel threaded rod. Steel threaded rod is certain...

49 CFR 178.46 - Specification 3AL seamless aluminum cylinders.

Code of Federal Regulations, 2012 CFR

2012-10-01

... circular. (5) All openings must be threaded. Threads must comply with the following: (i) Each thread must be clean cut, even, without checks, and to gauge. (ii) Taper threads, when used, must conform to one of the following: (A) American Standard Pipe Thread (NPT) type, conforming to the requirements of NBS...

49 CFR 178.46 - Specification 3AL seamless aluminum cylinders.

Code of Federal Regulations, 2014 CFR

2014-10-01

... circular. (5) All openings must be threaded. Threads must comply with the following: (i) Each thread must be clean cut, even, without checks, and to gauge. (ii) Taper threads, when used, must conform to one of the following: (A) American Standard Pipe Thread (NPT) type, conforming to the requirements of NBS...

49 CFR 178.46 - Specification 3AL seamless aluminum cylinders.

Code of Federal Regulations, 2013 CFR

2013-10-01

... circular. (5) All openings must be threaded. Threads must comply with the following: (i) Each thread must be clean cut, even, without checks, and to gauge. (ii) Taper threads, when used, must conform to one of the following: (A) American Standard Pipe Thread (NPT) type, conforming to the requirements of NBS...

49 CFR 178.46 - Specification 3AL seamless aluminum cylinders.

Code of Federal Regulations, 2011 CFR

2011-10-01

... circular. (5) All openings must be threaded. Threads must comply with the following: (i) Each thread must be clean cut, even, without checks, and to gauge. (ii) Taper threads, when used, must conform to one of the following: (A) American Standard Pipe Thread (NPT) type, conforming to the requirements of NBS...

AN MHD AVALANCHE IN A MULTI-THREADED CORONAL LOOP

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

Hood, A. W.; Cargill, P. J.; Tam, K. V.

For the first time, we demonstrate how an MHD avalanche might occur in a multithreaded coronal loop. Considering 23 non-potential magnetic threads within a loop, we use 3D MHD simulations to show that only one thread needs to be unstable in order to start an avalanche even when the others are below marginal stability. This has significant implications for coronal heating in that it provides for energy dissipation with a trigger mechanism. The instability of the unstable thread follows the evolution determined in many earlier investigations. However, once one stable thread is disrupted, it coalesces with a neighboring thread andmore » this process disrupts other nearby threads. Coalescence with these disrupted threads then occurs leading to the disruption of yet more threads as the avalanche develops. Magnetic energy is released in discrete bursts as the surrounding stable threads are disrupted. The volume integrated heating, as a function of time, shows short spikes suggesting that the temporal form of the heating is more like that of nanoflares than of constant heating.« less

Testing of Compact Bolted Fasteners with Insulation and Friction-Enhanced Shims for NCSX

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

L. E. Dudek, J.H. Chrzanowski, G. Gettelfinger, P. Heitzenroeder, S. Jurczynski, M. Viola and K. Freudenberg

The fastening of the National Compact Stellarator Experiment's (NCSX) modular coils presented a number of engineering and manufacturing challenges due to the high magnetic forces, need to control induced currents, tight tolerances and restrictive space envelope. A fastening method using high strength studs, jack nuts, insulating spacers, bushings and alumina coated shims was developed which met the requirements. A test program was conducted to verify the design. The tests included measurements of flatness of the spacers, determination of contact area, torque vs. tension of the studs and jack nuts, friction coefficient tests on the alumina and G-10 insulators, electrical tests,more » and tension relaxation tests due to temperature excursions from room temperature to liquid nitrogen temperatures. This paper will describe the design and the results of the test program.« less

Shear joint capability versus bolt clearance

NASA Technical Reports Server (NTRS)

Lee, H. M.

1992-01-01

The results of a conservative analysis approach into the determination of shear joint strength capability for typical space-flight hardware as a function of the bolt-hole clearance specified in the design are presented. These joints are comprised of high-strength steel fasteners and abutments constructed of aluminum alloys familiar to the aerospace industry. A general analytical expression was first arrived at which relates bolt-hole clearance to the bolt shear load required to place all joint fasteners into a shear transferring position. Extension of this work allowed the analytical development of joint load capability as a function of the number of fasteners, shear strength of the bolt, bolt-hole clearance, and the desired factor of safety. Analysis results clearly indicate that a typical space-flight hardware joint can withstand significant loading when less than ideal bolt hole clearances are used in the design.

Cribellate thread production in spiders: Complex processing of nano-fibres into a functional capture thread.

PubMed

Joel, Anna-Christin; Kappel, Peter; Adamova, Hana; Baumgartner, Werner; Scholz, Ingo

2015-11-01

Spider silk production has been studied intensively in the last years. However, capture threads of cribellate spiders employ an until now often unnoticed alternative of thread production. This thread in general is highly interesting, as it not only involves a controlled arrangement of three types of threads with one being nano-scale fibres (cribellate fibres), but also a special comb-like structure on the metatarsus of the fourth leg (calamistrum) for its production. We found the cribellate fibres organized as a mat, enclosing two parallel larger fibres (axial fibres) and forming the typical puffy structure of cribellate threads. Mat and axial fibres are punctiform connected to each other between two puffs, presumably by the action of the median spinnerets. However, this connection alone does not lead to the typical puffy shape of a cribellate thread. Removing the calamistrum, we found a functional capture thread still being produced, but the puffy shape of the thread was lost. Therefore, the calamistrum is not necessary for the extraction or combination of fibres, but for further processing of the nano-scale cribellate fibres. Using data from Uloborus plumipes we were able to develop a model of the cribellate thread production, probably universally valid for cribellate spiders. Copyright © 2015 Elsevier Ltd. All rights reserved.

Job Language Performance Requirements for MOS 13B, Cannon Crewman. Volume I & II.

DTIC Science & Technology

1982-10-01

COMPOUND :. Two or more sentences joined by: -1. Coordinating conjunction Explain the task and ask the trainees if they understand the task, end the...protective equipment belt loops boots closures )utton boot socks gas flap button )uttornhole fastened impregnated socks -lothing fastener knitted cuffs...liner t~seiuble it over performing. .. .duties protective ovtrboots )loves primary duties protective socks hours protective clothing shirt liner .nside

Dynamic Data Driven Methods for Self-aware Aerospace Vehicles

DTIC Science & Technology

2015-04-08

structural response model that incorporates multiple degradation or failure modes including damaged panel strength (BVID, thru- hole ), damaged panel...stiffness (BVID, thru- hole ), loose fastener, fretted fastener hole , and disbonded surface. • A new data-driven approach for the online updating of the flight...between the first and second plies. The panels were reinforced around the boarders of the panel with through holes to simulate mounting the wing skins to

Constructing Cost-Effective Crystal Structures with Table Tennis Balls and Tape That Allows Students to Assemble and Model Multiple Unit Cells

ERIC Educational Resources Information Center

Elsworth, Catherine; Li, Barbara T. Y.; Ten, Abilio

2017-01-01

In this letter we present an innovative and cost-effective method of constructing crystal structures using Dual Lock fastening adhesive tape with table tennis (ping pong) balls. The use of these fasteners allows the balls to be easily assembled into layers to model various crystal structures and unit cells and then completely disassembled again.…

Pilot Scott Horowitz fashions cord loop fasteners for a contingency spacewalk

NASA Image and Video Library

1997-02-16

S82-E-5597 (17 Feb. 1997) --- Astronaut Scott J. Horowitz at pilot's station works with a hand-fashioned loop fastener device to be used in support of the additional STS-82 Extravehicular Activity (EVA) to service Hubble Space Telescope (HST). Note sketches overhead which were sent by ground controllers to guide the pilot's engineering of the task. This view was taken with an Electronic Still Camera (ESC).

An Integrated Approach to Assess Exposure and Health-Risk from Polycyclic Aromatic Hydrocarbons (PAHs) in a Fastener Manufacturing Industry

PubMed Central

Hsu, Hsin-I; Lin, Ming-Yeng; Chen, Yu-Cheng; Chen, Wang-Yi; Yoon, Chungsik; Chen, Mei-Ru; Tsai, Perng-Jy

2014-01-01

An integrated approach was developed to assess exposure and health-risk from polycyclic aromatic hydrocarbons (PAHs) contained in oil mists in a fastener manufacturing industry. One previously developed model and one new model were adopted for predicting oil mist exposure concentrations emitted from metal work fluid (MWF) and PAHs contained in MWF by using the fastener production rate (Pr) and cumulative fastener production rate (CPr) as predictors, respectively. By applying the annual Pr and CPr records to the above two models, long-term workplace PAH exposure concentrations were predicted. In addition, true exposure data was also collected from the field. The predicted and measured concentrations respectively served as the prior and likelihood distributions in the Bayesian decision analysis (BDA), and the resultant posterior distributions were used to determine the long-term exposure and health-risks posed on workers. Results show that long term exposures to PAHs would result in a 3.1%, 96.7%, and 73.4% chance of exceeding the PEL-TWA (0.2 mg/m3), action level (0.1 mg/m3), and acceptable health risk (10−3), respectively. In conclusion, preventive measures should be taken immediately to reduce workers’ PAH exposures. PMID:25226413

PICH and BLM limit histone association with anaphase centromeric DNA threads and promote their resolution

PubMed Central

Ke, Yuwen; Huh, Jae-Wan; Warrington, Ross; Li, Bing; Wu, Nan; Leng, Mei; Zhang, Junmei; Ball, Haydn L; Li, Bing; Yu, Hongtao

2011-01-01

Centromeres nucleate the formation of kinetochores and are vital for chromosome segregation during mitosis. The SNF2 family helicase PICH (Plk1-interacting checkpoint helicase) and the BLM (the Bloom's syndrome protein) helicase decorate ultrafine histone-negative DNA threads that link the segregating sister centromeres during anaphase. The functions of PICH and BLM at these threads are not understood, however. Here, we show that PICH binds to BLM and enables BLM localization to anaphase centromeric threads. PICH- or BLM-RNAi cells fail to resolve these threads in anaphase. The fragmented threads form centromeric-chromatin-containing micronuclei in daughter cells. Anaphase threads in PICH- and BLM-RNAi cells contain histones and centromere markers. Recombinant purified PICH has nucleosome remodelling activities in vitro. We propose that PICH and BLM unravel centromeric chromatin and keep anaphase DNA threads mostly free of nucleosomes, thus allowing these threads to span long distances between rapidly segregating centromeres without breakage and providing a spatiotemporal window for their resolution. PMID:21743438

Understanding thread properties for red blood cell antigen assays: weak ABO blood typing.

PubMed

Nilghaz, Azadeh; Zhang, Liyuan; Li, Miaosi; Ballerini, David R; Shen, Wei

2014-12-24

"Thread-based microfluidics" research has so far focused on utilizing and manipulating the wicking properties of threads to form controllable microfluidic channels. In this study we aim to understand the separation properties of threads, which are important to their microfluidic detection applications for blood analysis. Confocal microscopy was utilized to investigate the effect of the microscale surface morphologies of fibers on the thread's separation efficiency of red blood cells. We demonstrated the remarkably different separation properties of threads made using silk and cotton fibers. Thread separation properties dominate the clarity of blood typing assays of the ABO groups and some of their weak subgroups (Ax and A3). The microfluidic thread-based analytical devices (μTADs) designed in this work were used to accurately type different blood samples, including 89 normal ABO and 6 weak A subgroups. By selecting thread with the right surface morphology, we were able to build μTADs capable of providing rapid and accurate typing of the weak blood groups with high clarity.

Effect of Thread and Rotating Speed on Material Flow Behavior and Mechanical Properties of Friction Stir Lap Welding Joints

NASA Astrophysics Data System (ADS)

Ji, Shude; Li, Zhengwei; Zhou, Zhenlu; Wu, Baosheng

2017-10-01

This study focused on the effects of thread on hook and cold lap formation, lap shear property and impact toughness of alclad 2024-T4 friction stir lap welding (FSLW) joints. Except the traditional threaded pin tool (TR-tool), three new tools with different thread locations and orientations were designed. Results showed that thread significantly affected hook, cold lap morphologies and lap shear properties. The tool with tip-threaded pin (T-tool) fabricated joint with flat hook and cold lap, which resulted in shear fracture mode. The tools with bottom-threaded pin (B-tool) eliminated the hook. The tool with reverse-threaded pin (R-tool) widened the stir zone width. When using configuration A, the joints fabricated by the three new tools showed higher failure loads than the joint fabricated by the TR-tool. The joint using the T-tool owned the optimum impact toughness. This study demonstrated the significance of thread during FSLW and provided a reference to optimize tool geometry.

Structural Turnbuckle Bears Compressive or Tensile Loads

NASA Technical Reports Server (NTRS)

Bateman, W. A.; Lang, C. H.

1985-01-01

Column length adjuster based on turnbuckle principle. Device consists of internally and externally threaded bushing, threaded housing and threaded rod. Housing attached to one part and threaded rod attached to other part of structure. Turning double threaded bushing contracts or extends rod in relation to housing. Once adjusted, bushing secured with jamnuts. Device used for axially loaded members requiring length adjustment during installation.

Do dual-thread orthodontic mini-implants improve bone/tissue mechanical retention?

PubMed

Lin, Yang-Sung; Chang, Yau-Zen; Yu, Jian-Hong; Lin, Chun-Li

2014-12-01

The aim of this study was to understand whether the pitch relationship between micro and macro thread designs with a parametrical relationship in a dual-thread mini-implant can improve primary stability. Three types of mini-implants consisting of single-thread (ST) (0.75 mm pitch in whole length), dual-thread A (DTA) with double-start 0.375 mm pitch, and dual-thread B (DTB) with single-start 0.2 mm pitch in upper 2-mm micro thread region for performing insertion and pull-out testing. Histomorphometric analysis was performed in these specimens in evaluating peri-implant bone defects using a non-contact vision measuring system. The maximum inserted torque (Tmax) in type DTA was found to be the smallest significantly, but corresponding values found no significant difference between ST and DTB. The largest pull-out strength (Fmax) in the DTA mini-implant was found significantly greater than that for the ST mini-implant regardless of implant insertion orientation. Mini-implant engaged the cortical bone well as observed in ST and DTA types. Dual-thread mini-implant with correct micro thread pitch (parametrical relationship with macro thread pitch) in the cortical bone region can improve primary stability and enhanced mechanical retention.

Three-dimensional optimization and sensitivity analysis of dental implant thread parameters using finite element analysis.

PubMed

Geramizadeh, Maryam; Katoozian, Hamidreza; Amid, Reza; Kadkhodazadeh, Mahdi

2018-04-01

This study aimed to optimize the thread depth and pitch of a recently designed dental implant to provide uniform stress distribution by means of a response surface optimization method available in finite element (FE) software. The sensitivity of simulation to different mechanical parameters was also evaluated. A three-dimensional model of a tapered dental implant with micro-threads in the upper area and V-shaped threads in the rest of the body was modeled and analyzed using finite element analysis (FEA). An axial load of 100 N was applied to the top of the implants. The model was optimized for thread depth and pitch to determine the optimal stress distribution. In this analysis, micro-threads had 0.25 to 0.3 mm depth and 0.27 to 0.33 mm pitch, and V-shaped threads had 0.405 to 0.495 mm depth and 0.66 to 0.8 mm pitch. The optimized depth and pitch were 0.307 and 0.286 mm for micro-threads and 0.405 and 0.808 mm for V-shaped threads, respectively. In this design, the most effective parameters on stress distribution were the depth and pitch of the micro-threads based on sensitivity analysis results. Based on the results of this study, the optimal implant design has micro-threads with 0.307 and 0.286 mm depth and pitch, respectively, in the upper area and V-shaped threads with 0.405 and 0.808 mm depth and pitch in the rest of the body. These results indicate that micro-thread parameters have a greater effect on stress and strain values.

SMT-Aware Instantaneous Footprint Optimization

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

Roy, Probir; Liu, Xu; Song, Shuaiwen

Modern architectures employ simultaneous multithreading (SMT) to increase thread-level parallelism. SMT threads share many functional units and the whole memory hierarchy of a physical core. Without a careful code design, SMT threads can easily contend with each other for these shared resources, causing severe performance degradation. Minimizing SMT thread contention for HPC applications running on dedicated platforms is very challenging, because they usually spawn threads within Single Program Multiple Data (SPMD) models. To address this important issue, we introduce a simple scheme for SMT-aware code optimization, which aims to reduce the memory contention across SMT threads.

SEM and fractography analysis of screw thread loosening in dental implants.

PubMed

Scarano, A; Quaranta, M; Traini, T; Piattelli, M; Piattelli, A

2007-01-01

Biological and technical failures of implants have already been reported. Mechanical factors are certainly of importance in implant failures, even if their exact nature has not yet been established. The abutment screw fracture or loosening represents a rare, but quite unpleasant failure. The aim of the present research is an analysis and structural examination of screw thread or abutment loosening compared with screw threads or abutment without loosening. The loosening of screw threads was compared to screw thread without loosening of three different implant systems; Branemark (Nobel Biocare, Gothenburg, Sweden), T.B.R. implant systems (Benax, Ancona, Italy) and Restore (Lifecore Biomedical, Chaska, Minnesota, USA). In this study broken screws were excluded. A total of 16 screw thread loosenings were observed (Group I) (4 Branemark, 4 T.B.R and 5 Restore), 10 screw threads without loosening were removed (Group II), and 6 screw threads as received by the manufacturer (unused) (Group III) were used as control (2 Branemark, 2 T.B.R and 2 Restore). The loosened abutment screws were retrieved and analyzed under SEM. Many alterations and deformations were present in concavities and convexities of screw threads in group I. No macroscopic alterations or deformations were observed in groups II and III. A statistical difference of the presence of microcracks were observed between screw threads with an abutment loosening and screw threads without an abutment loosening.

Precision Cleaning - Path to Premier

NASA Technical Reports Server (NTRS)

Mackler, Scott E.

2008-01-01

ITT Space Systems Division s new Precision Cleaning facility provides critical cleaning and packaging of aerospace flight hardware and optical payloads to meet customer performance requirements. The Precision Cleaning Path to Premier Project was a 2007 capital project and is a key element in the approved Premier Resource Management - Integrated Supply Chain Footprint Optimization Project. Formerly precision cleaning was located offsite in a leased building. A new facility equipped with modern precision cleaning equipment including advanced process analytical technology and improved capabilities was designed and built after outsourcing solutions were investigated and found lacking in ability to meet quality specifications and schedule needs. SSD cleans parts that can range in size from a single threaded fastener all the way up to large composite structures. Materials that can be processed include optics, composites, metals and various high performance coatings. We are required to provide verification to our customers that we have met their particulate and molecular cleanliness requirements and we have that analytical capability in this new facility. The new facility footprint is approximately half the size of the former leased operation and provides double the amount of throughput. Process improvements and new cleaning equipment are projected to increase 1st pass yield from 78% to 98% avoiding $300K+/yr in rework costs. Cost avoidance of $350K/yr will result from elimination of rent, IT services, transportation, and decreased utility costs. Savings due to reduced staff expected to net $4-500K/yr.

[The course of melanization and its inhibition in pupae of the cabbage whitePieris brassicae L.

PubMed

Bückmann, Detlef

1971-09-01

The melanization of the Cabbage White pupae varies in response to light conditions. As abdomina, which are isolated by a ligature, become strongly melanized, the control evidently works in the way of gradual inhibition.The melanine patches of light pupae are not paler than those of dark pupae, but they are smaller. Apparently there is a gradient of reactivity to inhibition from the margin of the patches towards their center. Different patches are affected by the inhibition to a different extent.The black patches appear during the first 6 hours after pupation, not simultaneously but in a certain sequence. The first and the last patches of this sequence are most reactive to inhibition. On light pupae they may be entirely absent.A classification of pupal melanization is based on differences in the shape of certain patches, which can easily be recognized even on operated pupae and isolated parts of the body.Equally strong melanization as from ligating results from nerve section between brain an suboesophageal ganglion, somewhat weaker melanization results from section between suboesophageal and prothoracic ganglia.The melanizing effects of ligatures and nerve sections decrease during a critical period. They are entirely lost 12 hours after the prepupa has fastened itself to the ground by spinning the girdle-thread.It is suggested that during this critical period a melanization inhibiting factor is secreted by a thoracic center, which itself is under nervous control of the brain.

A Moiré Pattern-Based Thread Counter

ERIC Educational Resources Information Center

Reich, Gary

2017-01-01

Thread count is a term used in the textile industry as a measure of how closely woven a fabric is. It is usually defined as the sum of the number of warp threads per inch (or cm) and the number of weft threads per inch. (It is sometimes confusingly described as the number of threads per square inch.) In recent years it has also become a subject of…

Does Simultaneous Liposuction Adversely Affect the Outcome of Thread Lifts? A Preliminary Result.

PubMed

Lee, Yong Woo; Park, Tae Hwan

2018-04-11

Along with advances in thread lift techniques and materials, ancillary procedures such as fat grafting, liposuction, or filler injections have been performed simultaneously. Some surgeons think that these ancillary procedures might affect the aesthetic outcomes of thread lifting possibly due to inadvertent injury to threads or loosening of soft tissue via passing the cannula in the surgical plane of the thread lifts. The purpose of the current study is to determine the effect of such ancillary procedures on the outcome of thread lifts in the human and cadaveric setting. We used human abdominal tissue after abdominoplasty and cadaveric faces. In the abdominal tissue, liposuction parallel to the parallel axis was performed in one area for 5 min. We counted 30 passes when liposuction was performed in one direction. This was repeated as we changed the direction of passages. The plane of thread lifts (dermal vs subcutaneous) and angle between liposuction and thread lifts (parallel vs perpendicular) were differentiated in this abdominal tissue study group. Then, we performed parallel or perpendicular thread lifts using a small slit incision. Using a tensiometer, the maximum holding strength was measured when pulling the thread out of the skin as much as possible. We also used faces of cadavers to prove whether the finding in human abdominal tissue is really valid with corresponding techniques. Our pilot study using abdominal tissue showed that liposuction after thread lifts adversely affects it regardless of the vector of thread lifts. In the cadaveric study, however, liposuction prior to thread lifting does not significantly affect the holding strength of thread lifts. Liposuction or fat grafting in the appropriate layer would not be a hurdle to safely performing simultaneous thread lifts if the target lift tissue is intra-SMAS or just above the SMAS layer. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Uncertainties in corrosion rate measurements of fasteners exposed to treated wood at 100% relative humidity

Treesearch

Samuel L. Zelinka

2007-01-01

This paper evaluates the effect that uncertainties in measurements of time, weight, and surface area have on the determination of the corrosion rate of metal fasteners in contact with wood. Three different types of nails were driven into alkaline copper quaternary (ACQ)-treated wood and exposed to 26.7°C (80°C) at 100 % relative humidity environment for up to 1 year....

Seals, Concrete Anchors, and Connections

DTIC Science & Technology

1989-02-01

brick. Medium to heavy I.. loads cannot be safely fastened to soft masonry materials (stuc-. : - . co. grout. plaster or plasterboard ) since such...588C, Type 1. Class A. Style 1 Use in: All masonry material Use in: Block, wallboard , plaster , hollow tile Use with: Sheet metal, wood or lag screws... Wallboard . plaster , paneling Use in: Wallboard or solid masonry Use with: No (- oer fastener needed Use with: Sheet metal screw Made of: Ste( Made of

Cadmium Replacements for High Strength Steel Fasteners

DTIC Science & Technology

2005-03-01

w/o corr expos – strippability (MIL-S-5002D) [fstnr & pnl] • bend test after coating reapplication • stress durability (ISO 15330) @ 96 hr before...Immersion Paint Adhesion -----45 washersGalvanic Bi-Metallic Corrosion Strippability Stress Durability Fatigue COF Torque Tension Breakaway Torque Paint...Patrick Doyle (NAWCADLKE) • Selected Issues – Zn vs Cad as control – Grade 8 (150 ksi) vs 180 ksi or 220 ksi fasteners – Use of dry film lubricants

Test results of smart aircraft fastener for KC-135 structural integrity

NASA Astrophysics Data System (ADS)

Schoess, Jeffrey N.; Seifert, Greg

1998-07-01

Hidden and inaccessible corrosion in aircraft structures is the number one logistics problem for the US Air Force, with an estimated maintenance cost in excess of $LR 1.0B per year in 1990-equivalent dollars. The Smart Aircraft Fastener Evaluation (SAFE) system was developed to provide early warning detection of corrosion-related symptoms in hidden locations of aircraft structures. The SAFE system incorporates an in situ measurement approach that measures and autonomously records several environmental conditions within a Hi-Lok aircraft fastener that could cause corrosion. The SAFE system integrates a miniature electrochemical microsensor array and a time-of-wetness sensor with an ultra low power 8-bit microcontroller and 4- Mbyte solid-state FLASH archival memory to measure evidence of active corrosion. A summary of the technical approach and a detailed analysis of the KC-135 lap joint test coupon results are presented.

Smart fastener for KC-135 structural integrity monitoring

NASA Astrophysics Data System (ADS)

Schoess, Jeffrey N.; Seifert, Greg

1997-06-01

Hidden and inaccessible corrosion in aircraft structures is the number-one logistics problem for the U.S. Air Force, with an estimated maintenance cost in excess of $DOL1.0 billion per year in 1990-equivalent dollars. The Smart Aircraft Fastener Evaluation (SAFE) system is being developed to provide early warning detection of corrosion- related symptoms in hidden locations of aircraft structures. The SAFE incorporates an in situ measurement approach that measures and autonomously records several environmental conditions (i.e., pH, temperature, chloride, free potential, time-of-wetness) within a Hi-Lok aircraft fastener that could cause corrosion to occur. The SAFE system integrates a miniature electrochemical microsensor array and a time-of- wetness sensor with an ultra-low-power 8-bit microcontroller and 5-Mbyte solid-state FLASH archival memory to measure the evidence of active corrosion. A summary of the technical approach, system design definition, software architecture, and future field test plans will be presented.

Photovoltaic module kit including connector assembly for non-penetrating array installation

DOEpatents

Botkin, Jonathan; Graves, Simon; Danning, Matt; Culligan, Matthew

2013-12-31

A PV module kit for non-penetrating rooftop installation, including a plurality of PV modules and a plurality of connectors. Each of the PV modules includes a PV laminate and a frame forming a mounting region assembled thereto. The connectors include a male connector having a male fastener extending from a head, and a female connector having a female fastener assempbled within a head. The heads are entirely formed of plastic. The kit provides a mounted array state including a junction at which the mounting regions of at least two of the PV modules are aligned and interconnected by engagement of the male connector with the female connector. The so-formed junction is substantially electrically insulated. The plurality of connectors can further include a spacer connector including a head forming a bore sized slidably receive the male fastener, with all of the connector heads being identical.

Photovoltaic module kit including connector assembly for non-penetrating array installation

DOEpatents

Botkin, Jonathan [El Cerrito, CA; Graves, Simon [Berkeley, CA; Danning, Matt [Oakland, CA; Culligan, Matthew [Berkeley, CA

2011-11-22

A PV module kit for non-penetrating rooftop installation, including a plurality of PV modules and a plurality of connectors. Each of the PV modules includes a PV laminate and a frame forming a mounting region assembled thereto. The connectors include a male connector having a male fastener extending from a head, and a female connector having a female fastener assembled within a head. The heads are entirely formed of plastic. The kit provides a mounted array state including a junction at which the mounting region of at least two of the PV modules are aligned and interconnected by engagement of the male connector with the female connector. The so-formed junction is substantially electrically insulated. The plurality of connectors can further include a spacer connector including a head forming a bore sized to slidably receive the male fastener, with all of the connector heads being identical.

Photovoltaic module kit including connector assembly for non-penetrating array installation

DOEpatents

Botkin, Jonathan; Graves, Simon; Danning, Matt; Culligan, Matthew

2012-10-23

A PV module kit for non-penetrating rooftop installation, including a plurality of PV modules and a plurality of connectors. Each of the PV modules includes a PV laminate and a frame forming a mounting region assembled thereto. The connectors include a male connector having a male fastener extending from a head, and a female connector having a female fastener assembled within a head. The heads are entirely formed of plastic. The kit provides a mounted array state including a junction at which the mounting region of at least two of the PV modules are aligned and interconnected by engagement of the male connector with the female connector. The so-formed junction is substantially electrically insulated. The plurality of connectors can further include a spacer connector including a head forming a bore sized to slidably receive the male fastener, with all of the connector heads being identical.

Automatic Fastening Large Structures: a New Approach

NASA Technical Reports Server (NTRS)

Lumley, D. F.

1985-01-01

The external tank (ET) intertank structure for the space shuttle, a 27.5 ft diameter 22.5 ft long externally stiffened mechanically fastened skin-stringer-frame structure, was a labor intensitive manual structure built on a modified Saturn tooling position. A new approach was developed based on half-section subassemblies. The heart of this manufacturing approach will be 33 ft high vertical automatic riveting system with a 28 ft rotary positioner coming on-line in mid 1985. The Automatic Riveting System incorporates many of the latest automatic riveting technologies. Key features include: vertical columns with two sets of independently operating CNC drill-riveting heads; capability of drill, insert and upset any one piece fastener up to 3/8 inch diameter including slugs without displacing the workpiece offset bucking ram with programmable rotation and deep retraction; vision system for automatic parts program re-synchronization and part edge margin control; and an automatic rivet selection/handling system.

Performance Characterization of Loctite (Registered Trademark) 242 and 271 Liquid Locking Compounds (LLCs) as a Secondary Locking Feature for International Space Station (ISS) Fasteners

NASA Technical Reports Server (NTRS)

Dube, Michael J.; Gamwell, Wayne R.

2011-01-01

Several International Space Station (ISS) hardware components use Loctite (and other polymer based liquid locking compounds (LLCs)) as a means of meeting the secondary (redundant) locking feature requirement for fasteners. The primary locking method is the fastener preload, with the application of the Loctite compound which when cured is intended to resist preload reduction. The reliability of these compounds has been questioned due to a number of failures during ground testing. The ISS Program Manager requested the NASA Engineering and Safety Center (NESC) to characterize and quantify sensitivities of Loctite being used as a secondary locking feature. The findings and recommendations provided in this investigation apply to the anaerobic LLCs Loctite 242 and 271. No other anaerobic LLCs were evaluated for this investigation. This document contains the findings and recommendations of the NESC investigation

Analysis of cold worked holes for structural life extension

NASA Technical Reports Server (NTRS)

Wieland, David H.; Cutshall, Jon T.; Burnside, O. Hal; Cardinal, Joseph W.

1994-01-01

Cold working holes for improved fatigue life of fastener holes are widely used on aircraft. This paper presents methods used by the authors to determine the percent of cold working to be applied and to analyze fatigue crack growth of cold worked fastener holes. An elastic, perfectly-plastic analysis of a thick-walled tube is used to determine the stress field during the cold working process and the residual stress field after the process is completed. The results of the elastic/plastic analysis are used to determine the amount of cold working to apply to a hole. The residual stress field is then used to perform damage tolerance analysis of a crack growing out of a cold worked fastener hole. This analysis method is easily implemented in existing crack growth computer codes so that the cold worked holes can be used to extend the structural life of aircraft. Analytical results are compared to test data where appropriate.

Recent Developments in Ground-Borne Noise and Vibration Control

NASA Astrophysics Data System (ADS)

Nelson, J. T.

1996-05-01

Vibration control provisions available to the transit designer include (among others) precision straightened rail, ballast mats, floating slabs and very soft direct fixation fasteners, in addition to rail grinding, wheel truing, and continuous welded rail. Recently, the Los Angeles Metro has developed specifications for a soft resilient direct fixation fastener to fit the same base dimensions as the standard direct fixation fastener. In San Francisco, low resonance frequency (8 Hz) floating slabs have been constructed to mitigate predicted ground vibration impacts at nearby residential structures. In Atlanta, low resonance frequency loading slabs have been constructed to maintain a low vibration environment in a medical building planned to be built over the subway structure. In Portland and Pasadena, ballast mats have been recommended to control light rail transit ground vibration impacts on housing located at typically 35 feet from the alignment. Each of these provisions are briefly described in view of recent applications at U.S. transit systems.

On the utility of threads for data parallel programming

NASA Technical Reports Server (NTRS)

Fahringer, Thomas; Haines, Matthew; Mehrotra, Piyush

1995-01-01

Threads provide a useful programming model for asynchronous behavior because of their ability to encapsulate units of work that can then be scheduled for execution at runtime, based on the dynamic state of a system. Recently, the threaded model has been applied to the domain of data parallel scientific codes, and initial reports indicate that the threaded model can produce performance gains over non-threaded approaches, primarily through the use of overlapping useful computation with communication latency. However, overlapping computation with communication is possible without the benefit of threads if the communication system supports asynchronous primitives, and this comparison has not been made in previous papers. This paper provides a critical look at the utility of lightweight threads as applied to data parallel scientific programming.

Ropes: Support for collective opertions among distributed threads

NASA Technical Reports Server (NTRS)

Haines, Matthew; Mehrotra, Piyush; Cronk, David

1995-01-01

Lightweight threads are becoming increasingly useful in supporting parallelism and asynchronous control structures in applications and language implementations. Recently, systems have been designed and implemented to support interprocessor communication between lightweight threads so that threads can be exploited in a distributed memory system. Their use, in this setting, has been largely restricted to supporting latency hiding techniques and functional parallelism within a single application. However, to execute data parallel codes independent of other threads in the system, collective operations and relative indexing among threads are required. This paper describes the design of ropes: a scoping mechanism for collective operations and relative indexing among threads. We present the design of ropes in the context of the Chant system, and provide performance results evaluating our initial design decisions.

Lack of ubiquitin immunoreactivities at both ends of neuropil threads. Possible bidirectional growth of neuropil threads.

PubMed

Iwatsubo, T; Hasegawa, M; Esaki, Y; Ihara, Y

1992-02-01

Immunocytochemically, neuropil threads (curly fibers) were investigated in the Alzheimer's disease brain using a confocal laser scanning fluorescence microscope by double labeling with tau/ubiquitin antibodies. Ubiquitin immunoreactivities were found to be lacking at one or both ends in more than 40% of tau-positive threads. Immunoelectron microscopy showed that bundles of paired helical filaments, which constitute neuropil threads, were positive for ubiquitin around their midportions, but often negative at their ends. Since it is reasonable to postulate that tau deposition as paired helical filaments precedes ubiquitination, the aforementioned observation suggests that the ends of the threads are newly formed portions, and thus the threads are often growing bidirectionally in small neuronal processes.

Gold thread implantation promotes hair growth in human and mice

PubMed Central

Kim, Jong-Hwan; Cho, Eun-Young; Kwon, Euna; Kim, Woo-Ho; Park, Jin-Sung; Lee, Yong-Soon

2017-01-01

Thread-embedding therapy has been widely applied for cosmetic purposes such as wrinkle reduction and skin tightening. Particularly, gold thread was reported to support connective tissue regeneration, but, its role in hair biology remains largely unknown due to lack of investigation. When we implanted gold thread and Happy Lift™ in human patient for facial lifting, we unexpectedly found an increase of hair regrowth in spite of no use of hair growth medications. When embedded into the depilated dorsal skin of mice, gold thread or polyglycolic acid (PGA) thread, similarly to 5% minoxidil, significantly increased the number of hair follicles on day 14 after implantation. And, hair re-growth promotion in the gold threadimplanted mice were significantly higher than that in PGA thread group on day 11 after depilation. In particular, the skin tissue of gold thread-implanted mice showed stronger PCNA staining and higher collagen density compared with control mice. These results indicate that gold thread implantation can be an effective way to promote hair re-growth although further confirmatory study is needed for more information on therapeutic mechanisms and long-term safety. PMID:29399026

Scheduler for multiprocessor system switch with selective pairing

DOEpatents

Gara, Alan; Gschwind, Michael Karl; Salapura, Valentina

2015-01-06

System, method and computer program product for scheduling threads in a multiprocessing system with selective pairing of processor cores for increased processing reliability. A selective pairing facility is provided that selectively connects, i.e., pairs, multiple microprocessor or processor cores to provide one highly reliable thread (or thread group). The method configures the selective pairing facility to use checking provide one highly reliable thread for high-reliability and allocate threads to corresponding processor cores indicating need for hardware checking. The method configures the selective pairing facility to provide multiple independent cores and allocate threads to corresponding processor cores indicating inherent resilience.

Threaded biliary inside stents are a safe and effective therapeutic option in cases of malignant hilar obstruction.

PubMed

Inatomi, Osamu; Bamba, Shigeki; Shioya, Makoto; Mochizuki, Yosuke; Ban, Hiromitsu; Tsujikawa, Tomoyuki; Saito, Yasuharu; Andoh, Akira; Fujiyama, Yoshihide

2013-02-14

Although endoscopic biliary stents have been accepted as part of palliative therapy for cases of malignant hilar obstruction, the optimal endoscopic management regime remains controversial. In this study, we evaluated the safety and efficacy of placing a threaded stent above the sphincter of Oddi (threaded inside plastic stents, threaded PS) and compared the results with those of other stent types. Patients with malignant hilar obstruction, including those requiring biliary drainage for stent occlusion, were selected. Patients received either one of the following endoscopic indwelling stents: threaded PS, conventional plastic stents (conventional PS), or metallic stents (MS). Duration of stent patency and the incident of complication were compared in these patients. Forty-two patients underwent placement of endoscopic indwelling stents (threaded PS = 12, conventional PS = 17, MS = 13). The median duration of threaded PS patency was significantly longer than that of conventional PS patency (142 vs. 32 days; P = 0.04, logrank test). The median duration of threaded PS and MS patency was not significantly different (142 vs. 150 days, P = 0.83). Stent migration did not occur in any group. Among patients who underwent threaded PS placement as a salvage therapy after MS obstruction due to tumor ingrowth, the median duration of MS patency was significantly shorter than that of threaded PS patency (123 vs. 240 days). Threaded PS are safe and effective in cases of malignant hilar obstruction; moreover, it is a suitable therapeutic option not only for initial drainage but also for salvage therapy.

Exploration of microfluidic devices based on multi-filament threads and textiles: A review

PubMed Central

Nilghaz, A.; Ballerini, D. R.; Shen, W.

2013-01-01

In this paper, we review the recent progress in the development of low-cost microfluidic devices based on multifilament threads and textiles for semi-quantitative diagnostic and environmental assays. Hydrophilic multifilament threads are capable of transporting aqueous and non-aqueous fluids via capillary action and possess desirable properties for building fluid transport pathways in microfluidic devices. Thread can be sewn onto various support materials to form fluid transport channels without the need for the patterned hydrophobic barriers essential for paper-based microfluidic devices. Thread can also be used to manufacture fabrics which can be patterned to achieve suitable hydrophilic-hydrophobic contrast, creating hydrophilic channels which allow the control of fluids flow. Furthermore, well established textile patterning methods and combination of hydrophilic and hydrophobic threads can be applied to fabricate low-cost microfluidic devices that meet the low-cost and low-volume requirements. In this paper, we review the current limitations and shortcomings of multifilament thread and textile-based microfluidics, and the research efforts to date on the development of fluid flow control concepts and fabrication methods. We also present a summary of different methods for modelling the fluid capillary flow in microfluidic thread and textile-based systems. Finally, we summarized the published works of thread surface treatment methods and the potential of combining multifilament thread with other materials to construct devices with greater functionality. We believe these will be important research focuses of thread- and textile-based microfluidics in future. PMID:24086179

Virtual estimates of fastening strength for pedicle screw implantation procedures

NASA Astrophysics Data System (ADS)

Linte, Cristian A.; Camp, Jon J.; Augustine, Kurt E.; Huddleston, Paul M.; Robb, Richard A.; Holmes, David R.

2014-03-01

Traditional 2D images provide limited use for accurate planning of spine interventions, mainly due to the complex 3D anatomy of the spine and close proximity of nerve bundles and vascular structures that must be avoided during the procedure. Our previously developed clinician-friendly platform for spine surgery planning takes advantage of 3D pre-operative images, to enable oblique reformatting and 3D rendering of individual or multiple vertebrae, interactive templating, and placement of virtual pedicle implants. Here we extend the capabilities of the planning platform and demonstrate how the virtual templating approach not only assists with the selection of the optimal implant size and trajectory, but can also be augmented to provide surrogate estimates of the fastening strength of the implanted pedicle screws based on implant dimension and bone mineral density of the displaced bone substrate. According to the failure theories, each screw withstands a maximum holding power that is directly proportional to the screw diameter (D), the length of the in-bone segm,ent of the screw (L), and the density (i.e., bone mineral density) of the pedicle body. In this application, voxel intensity is used as a surrogate measure of the bone mineral density (BMD) of the pedicle body segment displaced by the screw. We conducted an initial assessment of the developed platform using retrospective pre- and post-operative clinical 3D CT data from four patients who underwent spine surgery, consisting of a total of 26 pedicle screws implanted in the lumbar spine. The Fastening Strength of the planned implants was directly assessed by estimating the intensity - area product across the pedicle volume displaced by the virtually implanted screw. For post-operative assessment, each vertebra was registered to its homologous counterpart in the pre-operative image using an intensity-based rigid registration followed by manual adjustment. Following registration, the Fastening Strength was computed for each displaced bone segment. According to our preliminary clinical study, a comparison between Fastening Strength, displaced bone volume and mean voxel intensity showed similar results (p < 0.1) between the virtually templated plans and the post-operative outcome following the traditional clinical approach. This study has demonstrated the feasibility of the platform in providing estimates the pedicle screw fastening strength via virtual implantation, given the intrinsic vertebral geometry and bone mineral density, enabling the selection of the optimal implant dimension adn trajectory for improved strength.

Lack of ubiquitin immunoreactivities at both ends of neuropil threads. Possible bidirectional growth of neuropil threads.

PubMed Central

Iwatsubo, T.; Hasegawa, M.; Esaki, Y.; Ihara, Y.

1992-01-01

Immunocytochemically, neuropil threads (curly fibers) were investigated in the Alzheimer's disease brain using a confocal laser scanning fluorescence microscope by double labeling with tau/ubiquitin antibodies. Ubiquitin immunoreactivities were found to be lacking at one or both ends in more than 40% of tau-positive threads. Immunoelectron microscopy showed that bundles of paired helical filaments, which constitute neuropil threads, were positive for ubiquitin around their midportions, but often negative at their ends. Since it is reasonable to postulate that tau deposition as paired helical filaments precedes ubiquitination, the aforementioned observation suggests that the ends of the threads are newly formed portions, and thus the threads are often growing bidirectionally in small neuronal processes. Images Figure 1 Figure 2 PMID:1310831

Wedges for ultrasonic inspection

DOEpatents

Gavin, Donald A.

1982-01-01

An ultrasonic transducer device is provided which is used in ultrasonic inspection of the material surrounding a threaded hole and which comprises a wedge of plastic or the like including a curved threaded surface adapted to be screwed into the threaded hole and a generally planar surface on which a conventional ultrasonic transducer is mounted. The plastic wedge can be rotated within the threaded hole to inspect for flaws in the material surrounding the threaded hole.

Apparatus for accurately preloading auger attachment means for frangible protective material

NASA Technical Reports Server (NTRS)

Wood, K. E.

1983-01-01

Apparatus for preloading a spring loaded threaded member is described. The apparatus is formed of three telescoping tubes. The innermost tube has means to prevent rotation of the threaded member. The middle tube is threadedly engaged with the threaded member and by axial movement applies a preload thereto. The outer tube engages a nut which may be rotated to retain the threaded member in axial position to maintain the preload.

1001518

NASA Image and Video Library

2010-09-01

DEVELOPMENT TESTING BEING CONDUCTED AT THE REQUEST OF THE MSFC DYNAMICS, LOADS, AND STRENGTH BRANCH (EV31) TO STUDY THE FAILURE BEHAVIOR OF FASTENERS SUBJECTED TO COMBINED SHEAR AND TENSION LOADING. THE DATA FROM THIS TESTING WILL BE USED TO DEVELOP APPROPRIATE STRUCTURAL ANALYSIS METHODS AS PART OF A FASTENER STANDARDS EFFORT SPONSORED BY THE NASA ENGINEERING SAFETY CENTER (NESC). THE TEST FIXTURE WAS DESIGNED AND FABRICATED THROUGH THE MSFC MECHANICAL FABRICATION BRANCH (ES23). THE TESTING ORGANIZATION IS THE MSFC MATERIALS TEST BRANCH (EM10).

1001519

NASA Image and Video Library

2010-09-01

DEVELOPMENT TESTING BEING CONDUCTED AT THE REQUEST OF THE MSFC DYNAMICS, LOADS, AND STRENGTH BRANCH (EV31) TO STUDY THE FAILURE BEHAVIOR OF FASTENERS SUBJECTED TO COMBINED SHEAR AND TENSION LOADING. THE DATA FROM THIS TESTING WILL BE USED TO DEVELOP APPROPRIATE STRUCTURAL ANALYSIS METHODS AS PART OF A FASTENER STANDARDS EFFORT SPONSORED BY THE NASA ENGINEERING SAFETY CENTER (NESC). THE TEST FIXTURE WAS DESIGNED AND FABRICATED THROUGH THE MSFC MECHANICAL FABRICATION BRANCH (ES23). THE TESTING ORGANIZATION IS THE MSFC MATERIALS TEST BRANCH (EM10).

1001520

NASA Image and Video Library

2010-09-01

DEVELOPMENT TESTING BEING CONDUCTED AT THE REQUEST OF THE MSFC DYNAMICS, LOADS, AND STRENGTH BRANCH (EV31) TO STUDY THE FAILURE BEHAVIOR OF FASTENERS SUBJECTED TO COMBINED SHEAR AND TENSION LOADING. THE DATA FROM THIS TESTING WILL BE USED TO DEVELOP APPROPRIATE STRUCTURAL ANALYSIS METHODS AS PART OF A FASTENER STANDARDS EFFORT SPONSORED BY THE NASA ENGINEERING SAFETY CENTER (NESC). THE TEST FIXTURE WAS DESIGNED AND FABRICATED THROUGH THE MSFC MECHANICAL FABRICATION BRANCH (ES23). THE TESTING ORGANIZATION IS THE MSFC MATERIALS TEST BRANCH (EM10).

1001521

NASA Image and Video Library

2010-09-01

DEVELOPMENT TESTING BEING CONDUCTED AT THE REQUEST OF THE MSFC DYNAMICS, LOADS, AND STRENGTH BRANCH (EV31) TO STUDY THE FAILURE BEHAVIOR OF FASTENERS SUBJECTED TO COMBINED SHEAR AND TENSION LOADING. THE DATA FROM THIS TESTING WILL BE USED TO DEVELOP APPROPRIATE STRUCTURAL ANALYSIS METHODS AS PART OF A FASTENER STANDARDS EFFORT SPONSORED BY THE NASA ENGINEERING SAFETY CENTER (NESC). THE TEST FIXTURE WAS DESIGNED AND FABRICATED THROUGH THE MSFC MECHANICAL FABRICATION BRANCH (ES23). THE TESTING ORGANIZATION IS THE MSFC MATERIALS TEST BRANCH (EM10).

Human-Assisted-Manufacturing Model Library

DTIC Science & Technology

2012-06-01

Handwrite 1 Word Continuous H21 0.04515 1 Word Discontinuous H25 0.05375 1 Word Upper Case H35 0.07525 1 Character Continuous H4 0.0086...also needs to include the relationship that says “this fastener connects these parts”. If this information is not explicitly included in the design...fasteners (or structural interface definitions) have been attached. Note that if after doing this there is NOT a single tree, we can say that the

Development, Vibration, and Thermal Characterization of a Steady Operating Pulsed Power System for FRC Thrusters

DTIC Science & Technology

2015-04-01

to successfully operate after being exposed to the harsh launch vibration environment. 2. Uncover workmanship flaws such as loose fasteners or weak...uncover any workmanship errors in spite of exposing the PPUs to vibration levels in excess of what is expected for flight on any of the launchers ...successfully operate after being exposed to the harsh launch vibration environment. 2. Uncover workmanship flaws such as loose fasteners or weak

Seawater Corrosion of Fasteners in Various Structural Materials

DTIC Science & Technology

1976-04-01

17 - 4PH stainless steel. The seven bolt materials were: 2024 aluminum, anodized ASTM grade 5 steel, 304 and 316 stainless steels, A286 stain- less...performed well in titanium structures. Use of MP35N, A286, and 304 stainless steel fasteners for constantly immersed 17 - 4PH stainless steel structures...would have been satisfactory only if sealant was not used and if protection had been provided to the 17 - 4PH to minimize crevice corrosion. Additional

Evaluation and Application of GRP Composite Fasteners for Sonar Dome Components

DTIC Science & Technology

1999-10-01

the USA were contacted in order to obtain information on commercially available composite fasteners (see Koko et al. 1998). Information was obtained...Santa Anna, California, (1996). Koko , T.S., Connor, M.J. and Corbett, C.V. (1997). "Development of a Composite Fairing Band Assembly for A...Stainless Steel Sonar Dome". Proceedings ofiCCM-11, Gold Coast Australia, pp. I-426 - I-435. Koko , T.S. (1998). "Development of Prototype Composite

Form and function of cnidarian spirocysts. III. Ultrastructure of the thread and the function of spirocysts

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

Mariscal, R.N.; McLean, R.B.; Hand, C.

1977-01-01

Unlike most nematocysts, undischarged spirocyst threads bear hollow tubules rather than spines. The undischarged tubules are interconnected in hexagonal arrays and appear to be arranged in bundles along the length of the thread. Although the wall of the thread is folded in length and width, the tubules are not. Upon discharge and contact with sea water, the tubules solubilize and adhere to various substrates and prey. Traction between such objects and the everting thread causes the tubules to spin out into a web or meshwork of fine microfibrillae. Lack of contact of the everting thread with objects results in themore » tubules forming small droplets of partially solubilized material, some of which appear to be arranged in a helical pattern around the thread. The web or meshwork formed by the solubilized tubules in contact with various substrates probably serves to increase significantly the surface area and adhesive properties of the everted spirocyst thread.« less

Thread bonds in molecules

NASA Astrophysics Data System (ADS)

Ivlev, B.

2017-07-01

Unusual chemical bonds are proposed. Each bond is characterized by the thread of a small radius, 10-11 cm, extended between two nuclei in a molecule. An analogue of a potential well, of the depth of MeV scale, is formed within the thread. This occurs due to the local reduction of zero point electromagnetic energy. This is similar to formation of the Casimir well. The electron-photon interaction only is not sufficient for formation of thread state. The mechanism of electron mass generation is involved in the close vicinity, 10-16 cm, of the thread. Thread bonds are stable and cannot be created or destructed in chemical or optical processes.

Flare particle acceleration in the interaction of twisted coronal flux ropes

NASA Astrophysics Data System (ADS)

Threlfall, J.; Hood, A. W.; Browning, P. K.

2018-03-01

Aim. The aim of this work is to investigate and characterise non-thermal particle behaviour in a three-dimensional (3D) magnetohydrodynamical (MHD) model of unstable multi-threaded flaring coronal loops. Methods: We have used a numerical scheme which solves the relativistic guiding centre approximation to study the motion of electrons and protons. The scheme uses snapshots from high resolution numerical MHD simulations of coronal loops containing two threads, where a single thread becomes unstable and (in one case) destabilises and merges with an additional thread. Results: The particle responses to the reconnection and fragmentation in MHD simulations of two loop threads are examined in detail. We illustrate the role played by uniform background resistivity and distinguish this from the role of anomalous resistivity using orbits in an MHD simulation where only one thread becomes unstable without destabilising further loop threads. We examine the (scalable) orbit energy gains and final positions recovered at different stages of a second MHD simulation wherein a secondary loop thread is destabilised by (and merges with) the first thread. We compare these results with other theoretical particle acceleration models in the context of observed energetic particle populations during solar flares.

Long-term effect of the insoluble thread-lifting technique.

PubMed

Fukaya, Mototsugu

2017-01-01

Although the thread-lifting technique for sagging faces has become more common and popular, medical literature evaluating its effects is scarce. Studies on its long-term prognosis are particularly uncommon. One hundred individuals who had previously undergone insoluble thread-lifting were retrospectively investigated. Photos in frontal and oblique views from the first and last visits were evaluated by six female individuals by guessing the patients' ages. The mean guessed age was defined as the apparent age, and the difference between the real and apparent ages was defined as the youth value. The difference between the youth values before and after the thread-lift was defined as the rejuvenation effect and analyzed in relation to the time since the operation, the number of threads used and the number of thread-lift operations performed. The rejuvenation effect decreased over the first year after the operation, but showed an increasing trend thereafter. The rejuvenation effect increased with the number of threads used and the number of thread-lift operations performed. The insoluble thread-lifting technique appears to be associated with both early and late effects. The rejuvenation effect appeared to decrease during the first year, but increased thereafter. A multicenter trial is necessary to confirm these findings.

Infant Deaths and Injuries Associated with Wearable Blankets, Swaddle Wraps, and Swaddling

PubMed Central

McDonnell, Emily; Moon, Rachel Y.

2014-01-01

Objective To assess risks involved in using wearable blankets, swaddle wraps, and swaddling. Study design Retrospective review of incidents reported to the Consumer Product Safety Commission in 2004–2012. Results 36 incidents involving wearable blankets and swaddle wraps were reviewed, including 10 deaths, 2 injuries, and 12 incidents without injury. The median age at death was 3.5 months; 80% of deaths were attributed to positional asphyxia related to prone sleeping. 70% had additional risk factors, usually soft bedding. Two injuries involved tooth extraction from the zipper. The 12 incidents without injury reported concern for strangulation/suffocation when the swaddle wrap became wrapped around the face/neck, and potential choking hazard when the zipper detached. All 12 incidents involving swaddling in ordinary blankets resulted in death. The median age was 2 months; 58% of deaths were attributed to positional asphyxia related to prone sleeping. 92% involved additional risk factors, most commonly soft bedding. Conclusions Reports of sudden unexpected death in swaddled infants are rare. Risks can be reduced by placing infants supine, and discontinuing swaddling as soon as an infant’s earliest attempts to roll are observed. Risks can be further reduced by removing soft bedding and bumper pads from the sleep environment. When using commercial swaddle wraps, fasteners must be securely attached. PMID:24507866

Rover Wheel-Actuated Tool Interface

NASA Technical Reports Server (NTRS)

Matthews, Janet; Ahmad, Norman; Wilcox, Brian

2007-01-01

A report describes an interface for utilizing some of the mobility features of a mobile robot for general-purpose manipulation of tools and other objects. The robot in question, now undergoing conceptual development for use on the Moon, is the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) rover, which is designed to roll over gentle terrain or walk over rough or steep terrain. Each leg of the robot is a six-degree-of-freedom general purpose manipulator tipped by a wheel with a motor drive. The tool interface includes a square cross-section peg, equivalent to a conventional socket-wrench drive, that rotates with the wheel. The tool interface also includes a clamp that holds a tool on the peg, and a pair of fold-out cameras that provides close-up stereoscopic images of the tool and its vicinity. The field of view of the imagers is actuated by the clamp mechanism and is specific to each tool. The motor drive can power any of a variety of tools, including rotating tools for helical fasteners, drills, and such clamping tools as pliers. With the addition of a flexible coupling, it could also power another tool or remote manipulator at a short distance. The socket drive can provide very high torque and power because it is driven by the wheel motor.

Reconstruction of the esophagojejunostomy by double stapling method using EEA™ OrVil™ in laparoscopic total gastrectomy and proximal gastrectomy

PubMed Central

2011-01-01

Here we report the method of anastomosis based on double stapling technique (hereinafter, DST) using a trans-oral anvil delivery system (EEATM OrVilTM) for reconstructing the esophagus and lifted jejunum following laparoscopic total gastrectomy or proximal gastric resection. As a basic technique, laparoscopic total gastrectomy employed Roux-en-Y reconstruction, laparoscopic proximal gastrectomy employed double tract reconstruction, and end-to-side anastomosis was used for the cut-off stump of the esophagus and lifted jejunum. We used EEATM OrVilTM as a device that permitted mechanical purse-string suture similarly to conventional EEA, and endo-Surgitie. After the gastric lymph node dissection, the esophagus was cut off using an automated stapler. EEATM OrVilTM was orally and slowly inserted from the valve tip, and a small hole was created at the tip of the obliquely cut-off stump with scissors to let the valve tip pass through. Yarn was cut to disconnect the anvil from a tube and the anvil head was retained in the esophagus. The end-Surgitie was inserted at the right subcostal margin, and after the looped-shaped thread was wrapped around the esophageal stump opening, assisting Maryland forceps inserted at the left subcostal and left abdomen were used to grasp the left and right esophageal stump. The surgeon inserted anvil grasping forceps into the right abdomen, and after grasping the esophagus with the forceps, tightened the end Surgitie, thereby completing the purse-string suture on the esophageal stump. The main unit of the automated stapler was inserted from the cut-off stump of the lifted jejunum, and a trocar was made to pass through. To prevent dropout of the small intestines from the automated stapler, the automated stapler and the lifted jejunum were fastened with silk thread, the abdomen was again inflated, and the lifted jejunum was led into the abdominal cavity. When it was confirmed that the automated stapler and center rod were made completely linear, the anvil and the main unit were connected with each other and firing was carried out. Then, DST-based anastomosis was completed with no dog-ear. The method may facilitate safe laparoscopic anastomosis between the esophagus and reconstructed intestine. This is also considered to serve as a useful anastomosis technique for upper levels of the esophagus in laparotomy. PMID:21599911

Thread Migration in the Presence of Pointers

NASA Technical Reports Server (NTRS)

Cronk, David; Haines, Matthew; Mehrotra, Piyush

1996-01-01

Dynamic migration of lightweight threads supports both data locality and load balancing. However, migrating threads that contain pointers referencing data in both the stack and heap remains an open problem. In this paper we describe a technique by which threads with pointers referencing both stack and non-shared heap data can be migrated such that the pointers remain valid after migration. As a result, threads containing pointers can now be migrated between processors in a homogeneous distributed memory environment.

Real-time inextensible surgical thread simulation.

PubMed

Xu, Lang; Liu, Qian

2018-03-27

This paper discusses a real-time simulation method of inextensible surgical thread based on the Cosserat rod theory using position-based dynamics (PBD). The method realizes stable twining and knotting of surgical thread while including inextensibility, bending, twisting and coupling effects. The Cosserat rod theory is used to model the nonlinear elastic behavior of surgical thread. The surgical thread model is solved with PBD to achieve a real-time, extremely stable simulation. Due to the one-dimensional linear structure of surgical thread, the direct solution of the distance constraint based on tridiagonal matrix algorithm is used to enhance stretching resistance in every constraint projection iteration. In addition, continuous collision detection and collision response guarantee a large time step and high performance. Furthermore, friction is integrated into the constraint projection process to stabilize the twining of multiple threads and complex contact situations. Through comparisons with existing methods, the surgical thread maintains constant length under large deformation after applying the direct distance constraint in our method. The twining and knotting of multiple threads correspond to stable solutions to contact and friction forces. A surgical suture scene is also modeled to demonstrate the practicality and simplicity of our method. Our method achieves stable and fast simulation of inextensible surgical thread. Benefiting from the unified particle framework, the rigid body, elastic rod, and soft body can be simultaneously simulated. The method is appropriate for applications in virtual surgery that require multiple dynamic bodies.

High precision optomechanical assembly using threads as mechanical reference

NASA Astrophysics Data System (ADS)

Lamontagne, Frédéric; Desnoyers, Nichola; Bergeron, Guy; Cantin, Mario

2016-09-01

A convenient method to assemble optomechanical components is to use threaded interface. For example, lenses are often secured inside barrels using threaded rings. In other cases, multiple optical sub-assemblies such as lens barrels can be threaded to each other. Threads have the advantage to provide a simple assembly method, to be easy to manufacture, and to offer a compact mechanical design. On the other hand, threads are not considered to provide accurate centering between parts because of the assembly clearance between the inner and outer threads. For that reason, threads are often used in conjunction with precision cylindrical surfaces to limit the radial clearance between the parts to be centered. Therefore, tight manufacturing tolerances are needed on these pilot diameters, which affect the cost of the optical assembly. This paper presents a new optomechanical approach that uses threads as mechanical reference. This innovative method relies on geometric principles to auto-center parts to each other with a very low centering error that is usually less than 5 μm. The method allows to auto-center an optical group in a main barrel, to perform an axial adjustment of an optical group inside a main barrel, and to perform stacking of multiple barrels. In conjunction with the lens auto-centering method that also used threads as a mechanical reference, this novel solution opens new possibilities to realize a variety of different high precision optomechanical assemblies at lower cost.

Threaded biliary inside stents are a safe and effective therapeutic option in cases of malignant hilar obstruction

PubMed Central

2013-01-01

Background Although endoscopic biliary stents have been accepted as part of palliative therapy for cases of malignant hilar obstruction, the optimal endoscopic management regime remains controversial. In this study, we evaluated the safety and efficacy of placing a threaded stent above the sphincter of Oddi (threaded inside plastic stents, threaded PS) and compared the results with those of other stent types. Methods Patients with malignant hilar obstruction, including those requiring biliary drainage for stent occlusion, were selected. Patients received either one of the following endoscopic indwelling stents: threaded PS, conventional plastic stents (conventional PS), or metallic stents (MS). Duration of stent patency and the incident of complication were compared in these patients. Results Forty-two patients underwent placement of endoscopic indwelling stents (threaded PS = 12, conventional PS = 17, MS = 13). The median duration of threaded PS patency was significantly longer than that of conventional PS patency (142 vs. 32 days; P = 0.04, logrank test). The median duration of threaded PS and MS patency was not significantly different (142 vs. 150 days, P = 0.83). Stent migration did not occur in any group. Among patients who underwent threaded PS placement as a salvage therapy after MS obstruction due to tumor ingrowth, the median duration of MS patency was significantly shorter than that of threaded PS patency (123 vs. 240 days). Conclusions Threaded PS are safe and effective in cases of malignant hilar obstruction; moreover, it is a suitable therapeutic option not only for initial drainage but also for salvage therapy. PMID:23410217

Parallel Implementation of 3-D Iterative Reconstruction With Intra-Thread Update for the jPET-D4

NASA Astrophysics Data System (ADS)

Lam, Chih Fung; Yamaya, Taiga; Obi, Takashi; Yoshida, Eiji; Inadama, Naoko; Shibuya, Kengo; Nishikido, Fumihiko; Murayama, Hideo

2009-02-01

One way to speed-up iterative image reconstruction is by parallel computing with a computer cluster. However, as the number of computing threads increases, parallel efficiency decreases due to network transfer delay. In this paper, we proposed a method to reduce data transfer between computing threads by introducing an intra-thread update. The update factor is collected from each slave thread and a global image is updated as usual in the first K sub-iteration. In the rest of the sub-iterations, the global image is only updated at an interval which is controlled by a parameter L. In between that interval, the intra-thread update is carried out whereby an image update is performed in each slave thread locally. We investigated combinations of K and L parameters based on parallel implementation of RAMLA for the jPET-D4 scanner. Our evaluation used four workstations with a total of 16 slave threads. Each slave thread calculated a different set of LORs which are divided according to ring difference numbers. We assessed image quality of the proposed method with a hotspot simulation phantom. The figure of merit was the full-width-half-maximum of hotspots and the background normalized standard deviation. At an optimum K and L setting, we did not find significant change in the output images. We also applied the proposed method to a Hoffman phantom experiment and found the difference due to intra-thread update was negligible. With the intra-thread update, computation time could be reduced by about 23%.

78 FR 12718 - Certain Steel Threaded Rod From the People's Republic of China: Affirmative Final Determination...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-25

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-932] Certain Steel Threaded Rod... Preliminary Determination of the circumvention inquiry concerning the antidumping duty order on certain steel threaded rod (``steel threaded rod'') from the People's Republic of China (``PRC'').\\1\\ The period of...

Contribution of Gypsum Wallboard to Racking Resistance of Light-Frame Walls.

DTIC Science & Technology

1983-12-01

contribution to wall ’ ~sheathing to the framing members, and axial loads on racking resistance. Such information may lead to more diagonal braces used...wallboard was centered over the joint and fastened to the narrow face of the wood pieces using 1-1/4-inch drywall nails . Two nails were used to fasten...pulled apart placing a lateral load on the nailed connection, similar to the connector loading incurred at the nailed connection along the bottom plate of

Exploratory Investigation into the Durability of Beneficial Cold Worked Fastener Hole in Aluminum

NASA Technical Reports Server (NTRS)

Johnson, W. S.; Clark, David A.

1999-01-01

Cold working fastener holes in aluminum alloys is a widely used technique in the aerospace industry for improving the fatigue performance of structures. A compressive tangential stress introduced in the material during the cold working of the hole reduces the natural tendency of the material to crack at the holes under cyclic tensile loading. It is a lucrative technique for the aerospace industry in that it provides an increase in performance without any weight cost.

Linear-Elastic 2D and 3D Finite Element Contact Analysis of a Hole Containing a Circular Insert in a Fatigue Test Coupon

DTIC Science & Technology

2015-07-01

circular hole in an aluminium plate fitted with a titanium fastener that were computed using two-dimensional finite element contact analysis. By...used to validate the contact stress distributions associated with a circular hole in an aluminium plate fitted with a titanium fastener that were...fatigue life and aircraft structural integrity management of RAAF airframes. An aluminium coupon has been previously designed in support of the

Static Strength Characteristics of Mechanically Fastened Composite Joints

NASA Technical Reports Server (NTRS)

Fox, D. E.; Swaim, K. W.

1999-01-01

The analysis of mechanically fastened composite joints presents a great challenge to structural analysts because of the large number of parameters that influence strength. These parameters include edge distance, width, bolt diameter, laminate thickness, ply orientation, and bolt torque. The research presented in this report investigates the influence of some of these parameters through testing and analysis. A methodology is presented for estimating the strength of the bolt-hole based on classical lamination theory using the Tsai-Hill failure criteria and typical bolthole bearing analytical methods.

Nebo: An efficient, parallel, and portable domain-specific language for numerically solving partial differential equations

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

Earl, Christopher; Might, Matthew; Bagusetty, Abhishek

This study presents Nebo, a declarative domain-specific language embedded in C++ for discretizing partial differential equations for transport phenomena on multiple architectures. Application programmers use Nebo to write code that appears sequential but can be run in parallel, without editing the code. Currently Nebo supports single-thread execution, multi-thread execution, and many-core (GPU-based) execution. With single-thread execution, Nebo performs on par with code written by domain experts. With multi-thread execution, Nebo can linearly scale (with roughly 90% efficiency) up to 12 cores, compared to its single-thread execution. Moreover, Nebo’s many-core execution can be over 140x faster than its single-thread execution.

Three-dimensional imaging of threading dislocations in GaN crystals using two-photon excitation photoluminescence

NASA Astrophysics Data System (ADS)

Tanikawa, Tomoyuki; Ohnishi, Kazuki; Kanoh, Masaya; Mukai, Takashi; Matsuoka, Takashi

2018-03-01

The three-dimensional imaging of threading dislocations in GaN films was demonstrated using two-photon excitation photoluminescence. The threading dislocations were shown as dark lines. The spatial resolutions near the surface were about 0.32 and 3.2 µm for the in-plane and depth directions, respectively. The threading dislocations with a density less than 108 cm-2 were resolved, although the aberration induced by the refractive index mismatch was observed. The decrease in threading dislocation density was clearly observed by increasing the GaN film thickness. This can be considered a novel method for characterizing threading dislocations in GaN films without any destructive preparations.

On Designing Lightweight Threads for Substrate Software

NASA Technical Reports Server (NTRS)

Haines, Matthew

1997-01-01

Existing user-level thread packages employ a 'black box' design approach, where the implementation of the threads is hidden from the user. While this approach is often sufficient for application-level programmers, it hides critical design decisions that system-level programmers must be able to change in order to provide efficient service for high-level systems. By applying the principles of Open Implementation Analysis and Design, we construct a new user-level threads package that supports common thread abstractions and a well-defined meta-interface for altering the behavior of these abstractions. As a result, system-level programmers will have the advantages of using high-level thread abstractions without having to sacrifice performance, flexibility or portability.

Nebo: An efficient, parallel, and portable domain-specific language for numerically solving partial differential equations

DOE PAGES

Earl, Christopher; Might, Matthew; Bagusetty, Abhishek; ...

2016-01-26

This study presents Nebo, a declarative domain-specific language embedded in C++ for discretizing partial differential equations for transport phenomena on multiple architectures. Application programmers use Nebo to write code that appears sequential but can be run in parallel, without editing the code. Currently Nebo supports single-thread execution, multi-thread execution, and many-core (GPU-based) execution. With single-thread execution, Nebo performs on par with code written by domain experts. With multi-thread execution, Nebo can linearly scale (with roughly 90% efficiency) up to 12 cores, compared to its single-thread execution. Moreover, Nebo’s many-core execution can be over 140x faster than its single-thread execution.

Message passing with queues and channels

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

Dozsa, Gabor J; Heidelberger, Philip; Kumar, Sameer

In an embodiment, a reception thread receives a source node identifier, a type, and a data pointer from an application and, in response, creates a receive request. If the source node identifier specifies a source node, the reception thread adds the receive request to a fast-post queue. If a message received from a network does not match a receive request on a posted queue, a polling thread adds a receive request that represents the message to an unexpected queue. If the fast-post queue contains the receive request, the polling thread removes the receive request from the fast-post queue. If themore » receive request that was removed from the fast-post queue does not match the receive request on the unexpected queue, the polling thread adds the receive request that was removed from the fast-post queue to the posted queue. The reception thread and the polling thread execute asynchronously from each other.« less

A software bus for thread objects

NASA Technical Reports Server (NTRS)

Callahan, John R.; Li, Dehuai

1995-01-01

The authors have implemented a software bus for lightweight threads in an object-oriented programming environment that allows for rapid reconfiguration and reuse of thread objects in discrete-event simulation experiments. While previous research in object-oriented, parallel programming environments has focused on direct communication between threads, our lightweight software bus, called the MiniBus, provides a means to isolate threads from their contexts of execution by restricting communications between threads to message-passing via their local ports only. The software bus maintains a topology of connections between these ports. It routes, queues, and delivers messages according to this topology. This approach allows for rapid reconfiguration and reuse of thread objects in other systems without making changes to the specifications or source code. A layered approach that provides the needed transparency to developers is presented. Examples of using the MiniBus are given, and the value of bus architectures in building and conducting simulations of discrete-event systems is discussed.

49 CFR 178.42 - Specification 3E seamless steel cylinders.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (valves, fuse plugs, etc.) for those openings. Threads conforming to the following are required on openings. (1) Threads must be clean cut, even, without checks, and to gauge. (2) Taper threads, when used, must be of length not less than as specified for American Standard taper pipe threads. (3) Straight...

49 CFR 178.42 - Specification 3E seamless steel cylinders.

Code of Federal Regulations, 2013 CFR

2013-10-01

... (valves, fuse plugs, etc.) for those openings. Threads conforming to the following are required on openings. (1) Threads must be clean cut, even, without checks, and to gauge. (2) Taper threads, when used, must be of length not less than as specified for American Standard taper pipe threads. (3) Straight...

Neuropil threads occur in dendrites of tangle-bearing nerve cells.

PubMed

Braak, H; Braak, E

1988-01-01

Transparent Golgi preparations counterstained for Alzheimer's neurofibrillary changes rendered possible the demonstration of neuropil threads in defined cellular processes. Only dendrites of tangle-bearing cortical nerve cells were found to contain neuropil threads. Processes of glial cells as well as axons present in the material were devoid of neuropil threads.

49 CFR 178.42 - Specification 3E seamless steel cylinders.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (valves, fuse plugs, etc.) for those openings. Threads conforming to the following are required on openings. (1) Threads must be clean cut, even, without checks, and to gauge. (2) Taper threads, when used, must be of length not less than as specified for American Standard taper pipe threads. (3) Straight...

Threaded Cognition: An Integrated Theory of Concurrent Multitasking

ERIC Educational Resources Information Center

Salvucci, Dario D.; Taatgen, Niels A.

2008-01-01

The authors propose the idea of threaded cognition, an integrated theory of concurrent multitasking--that is, performing 2 or more tasks at once. Threaded cognition posits that streams of thought can be represented as threads of processing coordinated by a serial procedural resource and executed across other available resources (e.g., perceptual…

49 CFR 178.42 - Specification 3E seamless steel cylinders.

Code of Federal Regulations, 2011 CFR

2011-10-01

... (valves, fuse plugs, etc.) for those openings. Threads conforming to the following are required on openings. (1) Threads must be clean cut, even, without checks, and to gauge. (2) Taper threads, when used, must be of length not less than as specified for American Standard taper pipe threads. (3) Straight...

49 CFR 178.42 - Specification 3E seamless steel cylinders.

Code of Federal Regulations, 2014 CFR

2014-10-01

... (valves, fuse plugs, etc.) for those openings. Threads conforming to the following are required on openings. (1) Threads must be clean cut, even, without checks, and to gauge. (2) Taper threads, when used, must be of length not less than as specified for American Standard taper pipe threads. (3) Straight...

A Primer on the Effective Use of Threaded Discussion Forums.

ERIC Educational Resources Information Center

Kirk, James J.; Orr, Robert L.

Threaded discussion forums are asynchronous, World Wide Web-based discussions occurring under a number of different topics called threads. By allowing students to post, read, and respond to messages independently of time or place, threaded discussion forums give students an opportunity for deeper reflection and more thoughtful replies than chat…

46 CFR 164.023-7 - Performance; non-standard thread.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 6 2010-10-01 2010-10-01 false Performance; non-standard thread. 164.023-7 Section 164... Performance; non-standard thread. (a) Use Codes 1, 2, 3, 4BC, 4RB, 5 (any). Each non-standard thread which...) testing machine. (2) Single strand breaking strength (after weathering). After exposure in a sunshine...

46 CFR 164.023-7 - Performance; non-standard thread.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 6 2011-10-01 2011-10-01 false Performance; non-standard thread. 164.023-7 Section 164... Performance; non-standard thread. (a) Use Codes 1, 2, 3, 4BC, 4RB, 5 (any). Each non-standard thread which...) testing machine. (2) Single strand breaking strength (after weathering). After exposure in a sunshine...

Threaded average temperature thermocouple

NASA Technical Reports Server (NTRS)

Ward, Stanley W. (Inventor)

1990-01-01

A threaded average temperature thermocouple 11 is provided to measure the average temperature of a test situs of a test material 30. A ceramic insulator rod 15 with two parallel holes 17 and 18 through the length thereof is securely fitted in a cylinder 16, which is bored along the longitudinal axis of symmetry of threaded bolt 12. Threaded bolt 12 is composed of material having thermal properties similar to those of test material 30. Leads of a thermocouple wire 20 leading from a remotely situated temperature sensing device 35 are each fed through one of the holes 17 or 18, secured at head end 13 of ceramic insulator rod 15, and exit at tip end 14. Each lead of thermocouple wire 20 is bent into and secured in an opposite radial groove 25 in tip end 14 of threaded bolt 12. Resulting threaded average temperature thermocouple 11 is ready to be inserted into cylindrical receptacle 32. The tip end 14 of the threaded average temperature thermocouple 11 is in intimate contact with receptacle 32. A jam nut 36 secures the threaded average temperature thermocouple 11 to test material 30.

A Moiré Pattern-Based Thread Counter

NASA Astrophysics Data System (ADS)

Reich, Gary

2017-10-01

Thread count is a term used in the textile industry as a measure of how closely woven a fabric is. It is usually defined as the sum of the number of warp threads per inch (or cm) and the number of weft threads per inch. (It is sometimes confusingly described as the number of threads per square inch.) In recent years it has also become a subject of considerable interest and some controversy among consumers. Many consumers consider thread count to be a key measure of the quality or fineness of a fabric, especially bed sheets, and they seek out fabrics that advertise high counts. Manufacturers in turn have responded to this interest by offering fabrics with ever higher claimed thread counts (sold at ever higher prices), sometime achieving the higher counts by distorting the definition of the term with some "creative math." In 2005 the Federal Trade Commission noted the growing use of thread count in advertising at the retail level and warned of the potential for consumers to be misled by distortions of the definition.

Hyperunstable matrix proteins in the byssus of Mytilus galloprovincialis.

PubMed

Sagert, Jason; Waite, J Herbert

2009-07-01

The marine mussel Mytilus galloprovincialis is tethered to rocks in the intertidal zone by a holdfast known as the byssus. Functioning as a shock absorber, the byssus is composed of threads, the primary molecular components of which are collagen-containing proteins (preCOLs) that largely dictate the higher order self-assembly and mechanical properties of byssal threads. The threads contain additional matrix components that separate and perhaps lubricate the collagenous microfibrils during deformation in tension. In this study, the thread matrix proteins (TMPs), a glycine-, tyrosine- and asparagine-rich protein family, were shown to possess unique repeated sequence motifs, significant transcriptional heterogeneity and were distributed throughout the byssal thread. Deamidation was shown to occur at a significant rate in a recombinant TMP and in the byssal thread as a function of time. Furthermore, charge heterogeneity presumably due to deamidation was observed in TMPs extracted from threads. The TMPs were localized to the preCOL-containing secretory granules in the collagen gland of the foot and are assumed to provide a viscoelastic matrix around the collagenous fibers in byssal threads.

Self-cleaning threaded rod spinneret for high-efficiency needleless electrospinning

NASA Astrophysics Data System (ADS)

Zheng, Gaofeng; Jiang, Jiaxin; Wang, Xiang; Li, Wenwang; Zhong, Weizheng; Guo, Shumin

2018-07-01

High-efficiency production of nanofibers is the key to the application of electrospinning technology. This work focuses on multi-jet electrospinning, in which a threaded rod electrode is utilized as the needless spinneret to achieve high-efficiency production of nanofibers. A slipper block, which fits into and moves through the threaded rod, is designed to transfer polymer solution evenly to the surface of the rod spinneret. The relative motion between the slipper block and the threaded rod electrode promotes the instable fluctuation of the solution surface, thus the rotation of threaded rod electrode decreases the critical voltage for the initial multi-jet ejection and the diameter of nanofibers. The residual solution on the surface of threaded rod is cleaned up by the moving slipper block, showing a great self-cleaning ability, which ensures the stable multi-jet ejection and increases the productivity of nanofibers. Each thread of the threaded rod electrode serves as an independent spinneret, which enhances the electric field strength and constrains the position of the Taylor cone, resulting in high productivity of uniform nanofibers. The diameter of nanofibers decreases with the increase of threaded rod rotation speed, and the productivity increases with the solution flow rate. The rotation of electrode provides an excess force for the ejection of charged jets, which also contributes to the high-efficiency production of nanofibers. The maximum productivity of nanofibers from the threaded rod spinneret is 5-6 g/h, about 250-300 times as high as that from the single-needle spinneret. The self-cleaning threaded rod spinneret is an effective way to realize continuous multi-jet electrospinning, which promotes industrial applications of uniform nanofibrous membrane.

Multi-threading performance of Geant4, MCNP6, and PHITS Monte Carlo codes for tetrahedral-mesh geometry.

PubMed

Han, Min Cheol; Yeom, Yeon Soo; Lee, Hyun Su; Shin, Bangho; Kim, Chan Hyeong; Furuta, Takuya

2018-05-04

In this study, the multi-threading performance of the Geant4, MCNP6, and PHITS codes was evaluated as a function of the number of threads (N) and the complexity of the tetrahedral-mesh phantom. For this, three tetrahedral-mesh phantoms of varying complexity (simple, moderately complex, and highly complex) were prepared and implemented in the three different Monte Carlo codes, in photon and neutron transport simulations. Subsequently, for each case, the initialization time, calculation time, and memory usage were measured as a function of the number of threads used in the simulation. It was found that for all codes, the initialization time significantly increased with the complexity of the phantom, but not with the number of threads. Geant4 exhibited much longer initialization time than the other codes, especially for the complex phantom (MRCP). The improvement of computation speed due to the use of a multi-threaded code was calculated as the speed-up factor, the ratio of the computation speed on a multi-threaded code to the computation speed on a single-threaded code. Geant4 showed the best multi-threading performance among the codes considered in this study, with the speed-up factor almost linearly increasing with the number of threads, reaching ~30 when N  =  40. PHITS and MCNP6 showed a much smaller increase of the speed-up factor with the number of threads. For PHITS, the speed-up factors were low when N  =  40. For MCNP6, the increase of the speed-up factors was better, but they were still less than ~10 when N  =  40. As for memory usage, Geant4 was found to use more memory than the other codes. In addition, compared to that of the other codes, the memory usage of Geant4 more rapidly increased with the number of threads, reaching as high as ~74 GB when N  =  40 for the complex phantom (MRCP). It is notable that compared to that of the other codes, the memory usage of PHITS was much lower, regardless of both the complexity of the phantom and the number of threads, hardly increasing with the number of threads for the MRCP.

Smart aircraft fastener evaluation (SAFE) system: a condition-based corrosion detection system for aging aircraft

NASA Astrophysics Data System (ADS)

Schoess, Jeffrey N.; Seifert, Greg; Paul, Clare A.

1996-05-01

The smart aircraft fastener evaluation (SAFE) system is an advanced structural health monitoring effort to detect and characterize corrosion in hidden and inaccessible locations of aircraft structures. Hidden corrosion is the number one logistics problem for the U.S. Air Force, with an estimated maintenance cost of $700M per year in 1990 dollars. The SAFE system incorporates a solid-state electrochemical microsensor and smart sensor electronics in the body of a Hi-Lok aircraft fastener to process and autonomously report corrosion status to aircraft maintenance personnel. The long-term payoff for using SAFE technology will be in predictive maintenance for aging aircraft and rotorcraft systems, fugitive emissions applications such as control valves, chemical pipeline vessels, and industrial boilers. Predictive maintenance capability, service, and repair will replace the current practice of scheduled maintenance to substantially reduce operational costs. A summary of the SAFE concept, laboratory test results, and future field test plans is presented.

Mechanical fasteners used in historical Siberian shipbuilding: perspectives for metallurgical analysis

NASA Astrophysics Data System (ADS)

Goncharov, A. E.; Mednikov, D. M.; Karelin, N. M.; Nasyrov, I. R.

2017-10-01

Recent discoveries of shipwrecked vessels in the northern reaches of the river Yenisei led to a number of questions concerning the history of shipbuilding in Siberia and the technical features of the first vessels of the industrial era to navigate the Northern Sea Route and the Yenisei. One of these questions addresses the features of mechanical fasteners used in the construction of the Siberian vessels. The answer to this question may provide information on how the first vessels, constructed in Siberia during the 1870’s, were able to sail the high seas of the Arctic Ocean and reach European ports. In this paper, we provide a description of iron mechanical fasteners obtained from one shipwrecked vessel and discuss on the perspectives of a metallurgical analysis This research has been funded by a grant of the Russian Fund of Humanities Research (Russian Fund of Fundamental Research) and the Krasnoyarsk Regional Science Fund under Grant number 16-11-24010.

Steel bridge in interaction with modern slab track fastening systems under various vertical load levels

NASA Astrophysics Data System (ADS)

Stančík, Vojtěch; Ryjáček, Pavel; Vokáč, Miroslav

2017-09-01

In modern slab tracks the continuously welded rail (CWR) is coupled through the fastening system with the substructure. The resulting restriction of expansion movement causes significant rail stress increments, which in the case of extreme loading may cause rail failures. These interaction phenomenon effects are naturally higher on a bridge due to different deformation capabilities of the bridge and the CWR. The presented contribution aims at investigating the state of the art European direct fastening system that is suitable for application on steel bridges. Analysis involves experimental determination of its nonlinear longitudinal interaction parameters under various vertical loads and numerical validation. During experimental procedures a two and a half meter long laboratory sample equipped with four nodes of the Vossloh DFF 300 was tested. There have been checked both DFF 300 modifications using the skl 15 tension clamps and the low resistance skl B15 tension clamps. The effects of clamping force lowering on the interaction parameters have also been investigated. Results are discussed in the paper.

Experimental Observations for Determining the Maximum Torque Values to Apply to Composite Components Mechanically Joined With Fasteners (MSFC Center Director's Discretionary Fund Final Report, Proj. 03-13}

NASA Technical Reports Server (NTRS)

Thomas, F. P.

2006-01-01

Aerospace structures utilize innovative, lightweight composite materials for exploration activities. These structural components, due to various reasons including size limitations, manufacturing facilities, contractual obligations, or particular design requirements, will have to be joined. The common methodologies for joining composite components are the adhesively bonded and mechanically fastened joints and, in certain instances, both methods are simultaneously incorporated into the design. Guidelines and recommendations exist for engineers to develop design criteria and analyze and test composites. However, there are no guidelines or recommendations based on analysis or test data to specify a torque or torque range to apply to metallic mechanical fasteners used to join composite components. Utilizing the torque tension machine at NASA s Marshall Space Flight Center, an initial series of tests were conducted to determine the maximum torque that could be applied to a composite specimen. Acoustic emissions were used to nondestructively assess the specimens during the tests and thermographic imaging after the tests.

In-service tests of the effectiveness of vibration control measures on the BART rail transit system

NASA Astrophysics Data System (ADS)

Saurenman, Hugh; Phillips, James

2006-06-01

This paper presents results of a number of vibration measurements of the different track forms used on the current San Francisco Bay Area Rapid Transit (BART) system including floating slab, resiliently supported half-ties and high-resilience direct fixation fasteners in subway and one section of floating slab used on at-grade track. The goal was to obtain data that would improve the predictions of future vibration levels and perhaps lead to more cost effective vibration mitigation strategies for the proposed BART extension to San Jose. The tests show that the floating slabs are performing much as designed, the resiliently supported half-ties are less effective than expected, and the high resilience track fasteners are probably performing as expected although the results are clouded because of severe rail corrugation in the area where the new fasteners were installed. One unanticipated result is the apparent interaction of the floating slab resonance, the wheel rotation frequency, the bogie dynamics, and vibration propagation characteristics of the ground.

Exploring Elephant Seals in New Jersey: Preschoolers Use Collaborative Multimedia Albums

ERIC Educational Resources Information Center

Fantozzi, Victoria B.

2012-01-01

VoiceThread is a website that allows users to create multimedia slideshows, or "threads," and then open these threads to other users for commentary or collaboration. This article shares the experiences of one multiage (3- to 5-year-olds) preschool classroom's use of VoiceThread. The purpose of the article is to introduce early childhood educators…

A C++ Thread Package for Concurrent and Parallel Programming

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

Jie Chen; William Watson

1999-11-01

Recently thread libraries have become a common entity on various operating systems such as Unix, Windows NT and VxWorks. Those thread libraries offer significant performance enhancement by allowing applications to use multiple threads running either concurrently or in parallel on multiprocessors. However, the incompatibilities between native libraries introduces challenges for those who wish to develop portable applications.

A multi-threaded version of MCFM

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

Campbell, John M.; Ellis, R. Keith; Giele, Walter T.

We report on our findings modifying MCFM using OpenMP to implement multi-threading. By using OpenMP, the modified MCFM will execute on any processor, automatically adjusting to the number of available threads. We then modified the integration routine VEGAS to distribute the event evaluation over the threads, while combining all events at the end of every iteration to optimize the numerical integration. Furthermore, we took special care so that the results of the Monte Carlo integration were independent of the number of threads used, to facilitate the validation of the OpenMP version of MCFM.

Biomechanical analysis of occupant kinematics in rollover motor vehicle accidents: dynamic spit test.

PubMed

Sances, Anthony; Kumaresan, Srirangam; Clarke, Richard; Herbst, Brian; Meyer, Steve

2005-01-01

A better understanding of occupant kinematics in rollover accidents helps to advance biomechanical knowledge and to enhance the safety features of motor vehicles. While many rollover accident simulation studies have adopted the static approach to delineate the occupant kinematics in rollover accidents, very few studies have attempted the dynamic approach. The present work was designed to study the biomechanics of restrained occupants during rollover accidents using the steady-state dynamic spit test and to address the importance of keeping the lap belt fastened. Experimental tests were conducted using an anthropometric 50% Hybrid III dummy in a vehicle. The vehicle was rotated at 180 degrees/second and the dummy was restrained using a standard three-point restraint system. The lap belt of the dummy was fastened either by using the cinching latch plate or by locking the retractor. Three configurations of shoulder belt harness were simulated: shoulder belt loose on chest with cinch plate, shoulder belt under the left arm and shoulder belt behind the chest. In all tests, the dummy stayed within the confinement of the vehicle indicating that the securely fastened lap belt holds the dummy with dynamic movement of 3 1/2" to 4". The results show that occupant movement in rollover accidents is least affected by various shoulder harness positions with a securely fastened lap belt. The present study forms a first step in delineating the biomechanics of occupants in rollover accidents.

Nutrient Deprivation Induces Property Variations in Spider Gluey Silk

PubMed Central

Blamires, Sean J.; Sahni, Vasav; Dhinojwala, Ali; Blackledge, Todd A.; Tso, I-Min

2014-01-01

Understanding the mechanisms facilitating property variability in biological adhesives may promote biomimetic innovations. Spider gluey silks such as the spiral threads in orb webs and the gumfoot threads in cobwebs, both of which comprise of an axial thread coated by glue, are biological adhesives that have variable physical and chemical properties. Studies show that the physical and chemical properties of orb web gluey threads change when spiders are deprived of food. It is, however, unknown whether gumfoot threads undergo similar property variations when under nutritional stress. Here we tested whether protein deprivation induces similar variations in spiral and gumfoot thread morphology and stickiness. We manipulated protein intake for the orb web spider Nephila clavipes and the cobweb spider Latrodectus hesperus and measured the diameter, glue droplet volume, number of droplets per mm, axial thread width, thread stickiness and adhesive energy of their gluey silks. We found that the gluey silks of both species were stickier when the spiders were deprived of protein than when the spiders were fed protein. In N. clavipes a concomitant increase in glue droplet volume was found. Load-extension curves showed that protein deprivation induced glue property variations independent of the axial thread extensions in both species. We predicted that changes in salt composition of the glues were primarily responsible for the changes in stickiness of the silks, although changes in axial thread properties might also contribute. We, additionally, showed that N. clavipes' glue changes color under protein deprivation, probably as a consequence of changes to its biochemical composition. PMID:24523902

[Mechanical behaviour of three types of surgical knots using 4/0 monofilament].

PubMed

Gil Santos, Luis; Más-Estellés, Jorge; Salmerón Sánchez, Manuel; Barrios, Carlos

2012-01-01

To experimentally study the behaviour of 4 types of monofilament with 3 knotting techniques, very often used in surgery, employing mechanical tests. Four 4/0 monofilaments were chosen, two of nylon, and the other two of polypropylene. Three types of knot designs were made with each thread. The first design (D-S-S) consisted of a double half-knot (D) followed by one single (S) in the opposite direction, a third S in turn in the opposite direction. The configuration of the second design was D-S-D, and the third, S-S-D. A mechanical fracture test was performed by stretching the thread at a rate of 4N/s, the force and deformation being recorded at intervals of 100 ms. There was a decrease in the force and deformation in the tests on threads with knots compared to threads without knots. In all cases the rupture of the thread occurred in the knot area, presumably due to damage caused to the thread during the knotting process. The D-S-D knot had the greatest resistance with polypropylene threads, and S-S-D provided the greatest resistance with nylon threads Polypropylene threads, with D-S-D knots, should be more indicated to suture tissues that have to support great forces and with little deformation of the suture (e.g., tendons). Nylon threads, with S-S-D knots, would be better indicated for tissues that have to support smaller forces and that require greater elasticity (e.g., skin). Copyright © 2011 AEC. Published by Elsevier Espana. All rights reserved.

Reshaping the Energy Landscape Transforms the Mechanism and Binding Kinetics of DNA Threading Intercalation.

PubMed

Clark, Andrew G; Naufer, M Nabuan; Westerlund, Fredrik; Lincoln, Per; Rouzina, Ioulia; Paramanathan, Thayaparan; Williams, Mark C

2018-02-06

Molecules that bind DNA via threading intercalation show high binding affinity as well as slow dissociation kinetics, properties ideal for the development of anticancer drugs. To this end, it is critical to identify the specific molecular characteristics of threading intercalators that result in optimal DNA interactions. Using single-molecule techniques, we quantify the binding of a small metal-organic ruthenium threading intercalator (Δ,Δ-B) and compare its binding characteristics to a similar molecule with significantly larger threading moieties (Δ,Δ-P). The binding affinities of the two molecules are the same, while comparison of the binding kinetics reveals significantly faster kinetics for Δ,Δ-B. However, the kinetics is still much slower than that observed for conventional intercalators. Comparison of the two threading intercalators shows that the binding affinity is modulated independently by the intercalating section and the binding kinetics is modulated by the threading moiety. In order to thread DNA, Δ,Δ-P requires a "lock mechanism", in which a large length increase of the DNA duplex is required for both association and dissociation. In contrast, measurements of the force-dependent binding kinetics show that Δ,Δ-B requires a large DNA length increase for association but no length increase for dissociation from DNA. This contrasts strongly with conventional intercalators, for which almost no DNA length change is required for association but a large DNA length change must occur for dissociation. This result illustrates the fundamentally different mechanism of threading intercalation compared with conventional intercalation and will pave the way for the rational design of therapeutic drugs based on DNA threading intercalation.

Influence of Micro Threads Alteration on Osseointegration and Primary Stability of Implants: An FEA and In Vivo Analysis in Rabbits.

PubMed

Chowdhary, Ramesh; Halldin, Anders; Jimbo, Ryo; Wennerberg, Ann

2015-06-01

To describe the early bone tissue response to implants with and without micro threads designed to the full length of an oxidized titanium implant. A pair of two-dimensional finite element models was designed using a computer aided three-dimensional interactive application files of an implant model with micro threads in between macro threads and one without micro threads. Oxidized titanium implants with (test implants n=20) and without (control implants n=20) micro thread were prepared. A total of 12 rabbits were used and each received four implants. Insertion torque while implant placement and removal torque analysis after 4 weeks was performed in nine rabbits, and histomorphometric analysis in three rabbits, respectively. Finite element analysis showed less stress accumulation in test implant models with 31Mpa when compared with 62.2 Mpa in control implant model. Insertion and removal torque analysis did not show any statistical significance between the two implant designs. At 4 weeks, there was a significant difference between the two groups in the percentage of new bone volume and bone-to-implant contact in the femur (p< .05); however, not in the tibia. The effect of micro threads was prominent in the femur suggesting that micro threads promote bone formation. The stress distribution supported by the micro threads was especially effective in the cancellous bone. © 2013 Wiley Periodicals, Inc.

Mechanically fastened composite laminates subjected to combined bearing-bypass and shear loading

NASA Technical Reports Server (NTRS)

Madenci, Erdogan

1993-01-01

Bolts and rivets provide a means of load transfer in the construction of aircraft. However, they give rise to stress concentrations and are often the source and location of static and fatigue failures. Furthermore, fastener holes are prone to cracks during take-off and landing. These cracks present the most common origin of structural failures in aircraft. Therefore, accurate determination of the contact stresses associated with such loaded holes in mechanically fastened joints is essential to reliable strength evaluation and failure prediction. As the laminate is subjected to loading, the contact region, whose extent is not known, develops between the fastener and the hole boundary through this contact region, which consists of slip and no-slip zones due to friction. The presence of the unknown contact stress distribution over the contact region between the pin and the composite laminate, material anisotropy, friction between the pin and the laminate, pin-hole clearance, combined bearing-bypass and shear loading, and finite geometry of the laminate result in a complex non-linear problem. In the case of bearing-bypass loading in compression, this non-linear problem is further complicated by the presence of dual contact regions. Previous research concerning the analysis of mechanical joints subjected to combined bearing-bypass and shear loading is non-existent. In the case of bearing-bypass loading only, except for the study conducted by Naik and Crews (1991), others employed the concept of superposition which is not valid for this non-linear problem. Naik and Crews applied a linear finite element analysis with conditions along the pin-hole contact region specified as displacement constraint equations. The major shortcoming of this method is that the variation of the contract region as a function of the applied load should be known a priori. Also, their analysis is limited to symmetric geometry and material systems, and frictionless boundary conditions. Since the contact stress distribution and the contact region are not known a priori, they did not directly impose the boundary conditions appropriate for modelling the contact and on-contact regions between the fastener and the hole. Furthermore, finite element analysis is not suitable for iterative design calculations for optimizing laminate construction in the presence of fasteners under complex loading conditions. In this study, the solution method developed by Madenci and Ileri (1992a,b) has been extended to determine the contact stresses in mechanical joints under combined bearing-bypass and shear loading, and bearing-bypass loading in compression resulting in dual contact regions.

Thread scheduling for GPU-based OPC simulation on multi-thread

NASA Astrophysics Data System (ADS)

Lee, Heejun; Kim, Sangwook; Hong, Jisuk; Lee, Sooryong; Han, Hwansoo

2018-03-01

As semiconductor product development based on shrinkage continues, the accuracy and difficulty required for the model based optical proximity correction (MBOPC) is increasing. OPC simulation time, which is the most timeconsuming part of MBOPC, is rapidly increasing due to high pattern density in a layout and complex OPC model. To reduce OPC simulation time, we attempt to apply graphic processing unit (GPU) to MBOPC because OPC process is good to be programmed in parallel. We address some issues that may typically happen during GPU-based OPC simulation in multi thread system, such as "out of memory" and "GPU idle time". To overcome these problems, we propose a thread scheduling method, which manages OPC jobs in multiple threads in such a way that simulations jobs from multiple threads are alternatively executed on GPU while correction jobs are executed at the same time in each CPU cores. It was observed that the amount of GPU peak memory usage decreases by up to 35%, and MBOPC runtime also decreases by 4%. In cases where out of memory issues occur in a multi-threaded environment, the thread scheduler was used to improve MBOPC runtime up to 23%.

Nanofibre production in spiders without electric charge.

PubMed

Joel, Anna-Christin; Baumgartner, Werner

2017-06-15

Technical nanofibre production is linked to high voltage, because nanofibres are typically produced by electrospinning. In contrast, spiders have evolved a way to produce nanofibres without high voltage. These spiders are called cribellate spiders and produce nanofibres within their capture thread production. It is suggested that their nanofibres become frictionally charged when brushed over a continuous area on the calamistrum, a comb-like structure at the metatarsus of the fourth leg. Although there are indications that electrostatic charges are involved in the formation of the thread structure, final proof is missing. We proposed three requirements to validate this hypothesis: (1) the removal of any charge during or after thread production has an influence on the structure of the thread; (2) the characteristic structure of the thread can be regenerated by charging; and (3) the thread is attracted to or repelled from differently charged objects. None of these three requirements were proven true. Furthermore, mathematical calculations reveal that even at low charges, the calculated structural assembly of the thread does not match the observed reality. Electrostatic forces are therefore not involved in the production of cribellate capture threads. © 2017. Published by The Company of Biologists Ltd.

Final report on EURAMET.L-S21: `Supplementary comparison of parallel thread gauges'

NASA Astrophysics Data System (ADS)

Mudronja, Vedran; Šimunovic, Vedran; Acko, Bojan; Matus, Michael; Bánréti, Edit; István, Dicso; Thalmann, Rudolf; Lassila, Antti; Lillepea, Lauri; Bartolo Picotto, Gian; Bellotti, Roberto; Pometto, Marco; Ganioglu, Okhan; Meral, Ilker; Salgado, José Antonio; Georges, Vailleau

2015-01-01

The results of the comparison of parallel thread gauges between ten European countries are presented. Three thread plugs and three thread rings were calibrated in one loop. Croatian National Laboratory for Length (HMI/FSB-LPMD) acted as the coordinator and pilot laboratory of the comparison. Thread angle, thread pitch, simple pitch diameter and pitch diameter were measured. Pitch diameters were calibrated within 1a, 2a, 1b and 2b calibration categories in accordance with the EURAMET cg-10 calibration guide. A good agreement between the measurement results and differences due to different calibration categories are analysed in this paper. This comparison was a first EURAMET comparison of parallel thread gauges based on the EURAMET ctg-10 calibration guide, and has made a step towards the harmonization of future comparisons with the registration of CMC values for thread gauges. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Model for threading dislocations in metamorphic tandem solar cells on GaAs (001) substrates

NASA Astrophysics Data System (ADS)

Song, Yifei; Kujofsa, Tedi; Ayers, John E.

2018-02-01

We present an approximate model for the threading dislocations in III-V heterostructures and have applied this model to study the defect behavior in metamorphic triple-junction solar cells. This model represents a new approach in which the coefficient for second-order threading dislocation annihilation and coalescence reactions is considered to be determined by the length of misfit dislocations, LMD, in the structure, and we therefore refer to it as the LMD model. On the basis of this model we have compared the average threading dislocation densities in the active layers of triple junction solar cells using linearly-graded buffers of varying thicknesses as well as S-graded (complementary error function) buffers with varying thicknesses and standard deviation parameters. We have shown that the threading dislocation densities in the active regions of metamorphic tandem solar cells depend not only on the thicknesses of the buffer layers but on their compositional grading profiles. The use of S-graded buffer layers instead of linear buffers resulted in lower threading dislocation densities. Moreover, the threading dislocation densities depended strongly on the standard deviation parameters used in the S-graded buffers, with smaller values providing lower threading dislocation densities.

Present Situation of the Anti-Fatigue Processing of High-Strength Steel Internal Thread Based on Cold Extrusion Technology: A Review

NASA Astrophysics Data System (ADS)

Miao, Hong; Jiang, Cheng; Liu, Sixing; Zhang, Shanwen; Zhang, Yanjun

2017-03-01

The adoption of cold-extrusion forming for internal thread net forming becomes an important component of anti-fatigue processing with the development of internal thread processing towards high performance, low cost and low energy consumption. It has vast application foreground in the field of aviation, spaceflight, high speed train and etc. The internal thread processing and anti-fatigue manufacture technology are summarized. In terms of the perspective of processing quality and fatigue serving life, the advantages and disadvantages of the processing methods from are compared. The internal thread cold-extrusion processing technology is investigated for the purpose of improving the anti-fatigue serving life of internal thread. The superiorities of the plastic deformation law and surface integrity of the metal layer in the course of cold extrusion for improving its stability and economy are summed up. The proposed research forecasts the development tendency of the internal thread anti-fatigue manufacturing technology.

Press-fit versus threaded acetabular cups in total hip arthroplasty: Functional and radiological results after five years.

PubMed

Ellenrieder, Martin; Bader, Rainer; Bergschmidt, Philipp; Mittelmeier, Wolfram

2016-03-01

Prospectively the outcome after total hip replacement with a new threaded acetabular cup design was compared to an established press-fit cup. After 1, 2 and 5 years, the 36-item Short Form Health Survey, Western Ontario and McMaster University Osteoarthritis Index and Harris Hip Score revealed no significant differences between the two groups (each group: n=42 patients), except for a higher Harris Hip Score in the threaded cup group after five years (p=0.02). After five years, one threaded cup had a mild radiolucent line without further signs of loosening. All other cups of both groups (98.6%) showed a full osseous integration. The cup inclination angle ranged from 41-58° (threaded cups) to 39-77° (press-fit cups). The new threaded cup provides equivalent clinical outcomes and osseous integration but more precise implant positioning compared to the press-fit design. No complications typically ascribed to threaded cups (acetabular fractures, bone resorption, nerve impairment) occurred.

Multithreading with separate data to improve the performance of Backpropagation method

NASA Astrophysics Data System (ADS)

Dhamma, Mulia; Zarlis, Muhammad; Budhiarti Nababan, Erna

2017-12-01

Backpropagation is one method of artificial neural network that can make a prediction for a new data with learning by supervised of the past data. The learning process of backpropagation method will become slow if we give too much data for backpropagation method to learn the data. Multithreading with a separate data inside of each thread are being used in order to improve the performance of backpropagtion method . Base on the research for 39 data and also 5 times experiment with separate data into 2 thread, the result showed that the average epoch become 6490 when using 2 thread and 453049 epoch when using only 1 thread. The most lowest epoch for 2 thread is 1295 and 1 thread is 356116. The process of improvement is caused by the minimum error from 2 thread that has been compared to take the weight and bias value. This process will be repeat as long as the backpropagation do learning.

Effects of thread interruptions on tool pins in friction stir welding of AA6061

DOE PAGES

Reza-E-Rabby, Md.; Tang, Wei; Reynolds, Anthony P.

2017-06-21

In this paper, effects of pin thread and thread interruptions (flats) on weld quality and process response parameters during friction stir welding (FSW) of 6061 aluminium alloy were quantified. Otherwise, identical smooth and threaded pins with zero to four flats were adopted for FSW. Weldability and process response variables were examined. Results showed that threads with flats significantly improved weld quality and reduced in-plane forces. A three-flat threaded pin led to production of defect-free welds under all examined welding conditions. Spectral analyses of in-plane forces and weld cross-sectional analysis were performed to establish correlation among pin flats, force dynamics andmore » defect formation. Finally, the lowest in-plane force spectra amplitudes were consistently observed for defect-free welds.« less

Effects of thread interruptions on tool pins in friction stir welding of AA6061

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

Reza-E-Rabby, Md.; Tang, Wei; Reynolds, Anthony P.

In this paper, effects of pin thread and thread interruptions (flats) on weld quality and process response parameters during friction stir welding (FSW) of 6061 aluminium alloy were quantified. Otherwise, identical smooth and threaded pins with zero to four flats were adopted for FSW. Weldability and process response variables were examined. Results showed that threads with flats significantly improved weld quality and reduced in-plane forces. A three-flat threaded pin led to production of defect-free welds under all examined welding conditions. Spectral analyses of in-plane forces and weld cross-sectional analysis were performed to establish correlation among pin flats, force dynamics andmore » defect formation. Finally, the lowest in-plane force spectra amplitudes were consistently observed for defect-free welds.« less

Servicing a globally broadcast interrupt signal in a multi-threaded computer

DOEpatents

Attinella, John E.; Davis, Kristan D.; Musselman, Roy G.; Satterfield, David L.

2015-12-29

Methods, apparatuses, and computer program products for servicing a globally broadcast interrupt signal in a multi-threaded computer comprising a plurality of processor threads. Embodiments include an interrupt controller indicating in a plurality of local interrupt status locations that a globally broadcast interrupt signal has been received by the interrupt controller. Embodiments also include a thread determining that a local interrupt status location corresponding to the thread indicates that the globally broadcast interrupt signal has been received by the interrupt controller. Embodiments also include the thread processing one or more entries in a global interrupt status bit queue based on whether global interrupt status bits associated with the globally broadcast interrupt signal are locked. Each entry in the global interrupt status bit queue corresponds to a queued global interrupt.

VoiceThread as a Peer Review and Dissemination Tool for Undergraduate Research

NASA Astrophysics Data System (ADS)

Guertin, L. A.

2012-12-01

VoiceThread has been utilized in an undergraduate research methods course for peer review and final research project dissemination. VoiceThread (http://www.voicethread.com) can be considered a social media tool, as it is a web-based technology with the capacity to enable interactive dialogue. VoiceThread is an application that allows a user to place a media collection online containing images, audio, videos, documents, and/or presentations in an interface that facilitates asynchronous communication. Participants in a VoiceThread can be passive viewers of the online content or engaged commenters via text, audio, video, with slide annotations via a doodle tool. The VoiceThread, which runs across browsers and operating systems, can be public or private for viewing and commenting and can be embedded into any website. Although few university students are aware of the VoiceThread platform (only 10% of the students surveyed by Ng (2012)), the 2009 K-12 edition of The Horizon Report (Johnson et al., 2009) lists VoiceThread as a tool to watch because of the opportunities it provides as a collaborative learning environment. In Fall 2011, eleven students enrolled in an undergraduate research methods course at Penn State Brandywine each conducted their own small-scale research project. Upon conclusion of the projects, students were required to create a poster summarizing their work for peer review. To facilitate the peer review process outside of class, each student-created PowerPoint file was placed in a VoiceThread with private access to only the class members and instructor. Each student was assigned to peer review five different student posters (i.e., VoiceThread images) with the audio and doodle tools to comment on formatting, clarity of content, etc. After the peer reviews were complete, the students were allowed to edit their PowerPoint poster files for a new VoiceThread. In the new VoiceThread, students were required to video record themselves describing their research and taking the viewer through their poster in the VoiceThread. This new VoiceThread with their final presentations was open for public viewing but not public commenting. A formal assessment was not conducted on the student impact of using VoiceThread for peer review and final research presentations. From an instructional standpoint, requiring students to use audio for the peer review commenting seemed to result in lengthier and more detailed reviews, connected with specific poster features when the doodle tool was utilized. By recording themselves as a "talking head" for the final product, students were required to be comfortable and confident with presenting their research, similar to what would be expected at a conference presentation. VoiceThread is currently being tested in general education Earth science courses at Penn State Brandywine as a dissemination tool for classroom-based inquiry projects and recruitment tool for Earth & Mineral Science majors.

Photovoltaic array mounting apparatus, systems, and methods

DOEpatents

West, Jack Raymond; Atchley, Brian; Hudson, Tyrus Hawkes; Johansen, Emil

2015-04-14

A photovoltaic array, including: (a) supports laid out on a surface in rows and columns; (b) photovoltaic modules positioned on top of the supports; and (c) fasteners connecting the photovoltaic modules to the supports, wherein the supports have an upper pedestal surface and a lower pedestal surface such that the photovoltaic modules are positioned at a non-horizontal angle when edges of the photovoltaic modules are positioned on top of the upper and lower pedestal surfaces, and wherein a portion of the fasteners rotate to lock the photovoltaic modules onto the supports.