Sample records for yarn pull-out behavior

  1. Study on Single-yarn Pullout Test of Ballistic Resistant Fabric under Different Preloads

    NASA Astrophysics Data System (ADS)

    Fang, Q. C.; Lei, Z. K.; Y Qin, F.; Li, W. K.; Bai, R. X.

    2017-12-01

    During bullet penetrating fabric, the pull-out force of yarn in fabric is related to the impact resistance of fabric when the yarn is pulled out from the fabric. The complex uncrimping and friction slip behavior occur during the yarn pullout process, which is critical to learn the impact resistance of fabric. Based on digital image correlation technique, the deformation behavior of Kevlar 49 fabric subjected to preload during the single-yarn pullout process was studied in this paper. The pullout force and displacement curve shows a straight rise and an oscillated decrease. In the linear rise stage, the yarn uncrimping causes a static friction effect. The maximum of the pullout force is not linearly increased with the preload. In the oscillating descending stage, the local descent of the pullout force indicates that the yarn end is gradually withdrawn from the fabric, and the local rise indicates that the yarn end moves to the next weft/warp interaction until the yarn is completely pulled out. The shear deformation of fabric corresponds to the single-yarn pullout process.

  2. Study the relation between the yarn pulling force and the bursting strength of single jersey knitted fabric

    NASA Astrophysics Data System (ADS)

    El-Tarfawy, S. Y.

    2017-10-01

    There are various methods to evaluate knitted fabric’s properties; the yarn pulling force is a suitable experimental method to investigate the properties of single jersey knitted fabric.In this study, a frame is attached to the electronic tensile strength tester to fix different single jersey knitted fabrics with different dimensional properties. A hook is connected to the upper load cell in the tensile tester to ravel the first upper course then records the values of the yarn pulling force. In addition to that, the effect of the loop length, yarn count, and raw material on yarn pulling force and specific fabric bursting strength are studied. It is concluded that yarn pulling force has a significant relation with specific fabric bursting strength.

  3. TWO-LAYER MODEL FOR PULL-OUT BEHAVIOR OF POST-INSTALLED ANCHOR

    NASA Astrophysics Data System (ADS)

    Saleem, Muhammad; Tsubaki, Tatsuya

    A new two-layer anchor-infill assembly structure for the post-installed anchor is introduced with the analytical model to simulate its pull-out deformational response. The post-installed anchor is such that used in strengthening techniques for reinforced concrete structures. The properties of the infill material used for post-installed anchor are characterized by nonlinear interfaces. Because of the mechanical properties of the infill layer the existing pull-out model of deformed bars is not applicable in this case. Interfacial de-bonding is examined using energy criterion and strength criterion. The effect of the interface properties such as stiffness and strength on the pull-out behavior of a post-installed anchor is investigated. Using sensitivity analysis, the effect of these parameters on load-displacement curve, shear stress distribution, de-bonded length and damage to the surrounding concrete is clarified. Then, the optimum combination of these parameters is presented. It is confirmed that the elastic modulus of infill should be large to reduce the pull-out displacement and the increase of the shear strength of infill makes the pull-out load larger.

  4. Experimental Investigations on the Pull-Out Behavior of Tire Strips Reinforced Sands

    PubMed Central

    Li, Li-Hua; Chen, Yan-Jun; Ferreira, Pedro Miguel Vaz; Liu, Yong; Xiao, Heng-Lin

    2017-01-01

    Waste tires have excellent mechanical performance and have been used as reinforcing material in geotechnical engineering; however, their interface properties are poorly understood. To further our knowledge, this paper examines the pull-out characteristics of waste tire strips in a compacted sand, together with uniaxial and biaxial geogrids also tested under the same conditions. The analysis of the results shows that the interlocking effect and pull-out resistance between the tire strip and the sand is very strong and significantly higher than that of the geogrids. In the early stages of the pull-out test, the resistance is mainly provided by the front portion of the embedded tire strips, as the pull-out test continues, more and more of the areas towards the end of the tire strips are mobilized, showing a progressive failure mechanism. The deformations are proportional to the frictional resistance between the tire-sand interface, and increase as the normal stresses increase. Tire strips of different wear intensities were tested and presented different pull-out resistances; however, the pull-out resistance mobilization patterns were generally similar. The pull-out resistance values obtained show that rubber reinforcement can provide much higher pull-out forces than the geogrid reinforcements tested here, showing that waste tires are an excellent alternative as a reinforcing system, regardless of the environmental advantages. PMID:28773069

  5. Experimental Investigations on the Pull-Out Behavior of Tire Strips Reinforced Sands.

    PubMed

    Li, Li-Hua; Chen, Yan-Jun; Ferreira, Pedro Miguel Vaz; Liu, Yong; Xiao, Heng-Lin

    2017-06-27

    Waste tires have excellent mechanical performance and have been used as reinforcing material in geotechnical engineering; however, their interface properties are poorly understood. To further our knowledge, this paper examines the pull-out characteristics of waste tire strips in a compacted sand, together with uniaxial and biaxial geogrids also tested under the same conditions. The analysis of the results shows that the interlocking effect and pull-out resistance between the tire strip and the sand is very strong and significantly higher than that of the geogrids. In the early stages of the pull-out test, the resistance is mainly provided by the front portion of the embedded tire strips, as the pull-out test continues, more and more of the areas towards the end of the tire strips are mobilized, showing a progressive failure mechanism. The deformations are proportional to the frictional resistance between the tire-sand interface, and increase as the normal stresses increase. Tire strips of different wear intensities were tested and presented different pull-out resistances; however, the pull-out resistance mobilization patterns were generally similar. The pull-out resistance values obtained show that rubber reinforcement can provide much higher pull-out forces than the geogrid reinforcements tested here, showing that waste tires are an excellent alternative as a reinforcing system, regardless of the environmental advantages.

  6. A theoretical analysis of deformation behavior of auxetic plied yarn structure

    NASA Astrophysics Data System (ADS)

    Zeng, Jifang; Hu, Hong

    2018-07-01

    This paper presents a theoretical analysis of the auxetic plied yarn (APY) structure formed with two types of single yarns having different diameter and modulus. A model which can be used to predict its deformation behavior under axial extension is developed based on the theoretical analysis. The developed model is first compared with the experimental data obtained in the previous study, and then used to predict the effects of different structural and material parameters on the auxetic behavior of the APY. The calculation results show that the developed model can correctly predict the variation trend of the auxetic behavior of the APY, which first increases and then decrease with the increase of the axial strain. The calculation results also indicate that the auxetic behavior of the APY simultaneously depends on the diameter ratio of the soft yarn and stiff yarn as well as the ratio between the pitch length and stiff yarn diameter. The study provides a way to design and fabricate APYs with the same auxetic behavior by using different soft and stiff yarns as long as these two ratios are kept unchanged.

  7. Investigation on Bond-Slip Behavior of Z-Pin Interfaces in X-Cor® Sandwich Structures Using Z-Pin Pull-Out Test

    NASA Astrophysics Data System (ADS)

    Shan, Hangying; Xiao, Jun; Chu, Qiyi

    2018-05-01

    The Z-Pin interfacial bond properties play an important role in the structural performance of X-Cor® sandwich structures. This paper presents an experimental investigation on bond-slip behavior of Z-Pin interfaces using Z-Pin pull-out test. Based on the experimental data the whole Z-Pin pull-out process consists of three stages: initial bonding, debonding and frictional sliding. Comparative experimental study on the influence of design parameters on bond-slip behavior of Z-Pin interfaces has also been performed. Numerical analyses were conducted with the ABAQUS finite element (FE) program to simulate the Z-Pins bond-slip response of the pull-out test. The Z-Pins interfacial bond-slip behavior was implemented using nonlinear spring elements characterized with the constitutive relation from experimental results. Numerical results were validated by comparison with experimental data, and reasonably good agreement was achieved between experimental and analytical pull-out force-slip curves.

  8. Full-field fabric stress mapping by micro Raman spectroscopy in a yarn push-out test.

    PubMed

    Lei, Z K; Qin, F Y; Fang, Q C; Bai, R X; Qiu, W; Chen, X

    2018-02-01

    The full-field stress distribution of a two-dimensional plain fabric was mapped using micro Raman spectroscopy (MRS) through a novel yarn push-out test, simulating a quasi-static projectile impact on the fabric. The stress-strain relationship for a single yarn was established using a digital image correlation method in a single-yarn tensile test. The relationship between Raman peak shift and aramid Kevlar 49 yarn stress was established using MRS in a single-yarn tensile test. An out-of-plane loading test was conducted on an aramid Kevlar 49 plain fabric, and the yarn stress was measured using MRS. From the full-field fabric stress distribution, it can be observed that there is a cross-shaped distribution of high yarn stress; this result would be helpful in further studies on load transfer on a fabric during a projectile impact.

  9. Pull-out simulations of a capped carbon nanotube in carbon nanotube-reinforced nanocomposites

    NASA Astrophysics Data System (ADS)

    Li, Y.; Liu, S.; Hu, N.; Han, X.; Zhou, L.; Ning, H.; Wu, L.; Alamusi, Yamamoto, G.; Chang, C.; Hashida, T.; Atobe, S.; Fukunaga, H.

    2013-04-01

    Systematic atomic simulations based on molecular mechanics were conducted to investigate the pull-out behavior of a capped carbon nanotube (CNT) in CNT-reinforced nanocomposites. Two common cases were studied: the pull-out of a complete CNT from a polymer matrix in a CNT/polymer nanocomposite and the pull-out of the broken outer walls of a CNT from the intact inner walls (i.e., the sword-in-sheath mode) in a CNT/alumina nanocomposite. By analyzing the obtained relationship between the energy increment (i.e., the difference in the potential energy between two consecutive pull-out steps) and the pull-out displacement, a set of simple empirical formulas based on the nanotube diameter was developed to predict the corresponding pull-out force. The predictions from these formulas are quite consistent with the experimental results. Moreover, the much higher pull-out force for a capped CNT than that of the corresponding open-ended CNT implies a significant contribution from the CNT cap to the interfacial properties of the CNT-reinforced nanocomposites. This finding provides a valuable insight for designing nanocomposites with desirable mechanical properties.

  10. Pull-out simulations of a capped carbon nanotube in carbon nanotube-reinforced nanocomposites

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

    Li, Y.; Liu, S.; Hu, N.

    2013-04-14

    Systematic atomic simulations based on molecular mechanics were conducted to investigate the pull-out behavior of a capped carbon nanotube (CNT) in CNT-reinforced nanocomposites. Two common cases were studied: the pull-out of a complete CNT from a polymer matrix in a CNT/polymer nanocomposite and the pull-out of the broken outer walls of a CNT from the intact inner walls (i.e., the sword-in-sheath mode) in a CNT/alumina nanocomposite. By analyzing the obtained relationship between the energy increment (i.e., the difference in the potential energy between two consecutive pull-out steps) and the pull-out displacement, a set of simple empirical formulas based on themore » nanotube diameter was developed to predict the corresponding pull-out force. The predictions from these formulas are quite consistent with the experimental results. Moreover, the much higher pull-out force for a capped CNT than that of the corresponding open-ended CNT implies a significant contribution from the CNT cap to the interfacial properties of the CNT-reinforced nanocomposites. This finding provides a valuable insight for designing nanocomposites with desirable mechanical properties.« less

  11. Effect of particle hardness on the penetration behavior of fabrics intercalated with dry particles and concentrated particle-fluid suspensions.

    PubMed

    Kalman, Dennis P; Merrill, Richard L; Wagner, Norman J; Wetzel, Eric D

    2009-11-01

    The penetration behavior of Kevlar fabric intercalated with dry particles and shear thickening fluids (STF), highly concentrated fluid-particle suspensions, is presented. In particular, the role of particle hardness is explored by comparing fabric treatments containing SiO(2) particles, which are significantly harder than Kevlar, to treatments containing softer poly(methyl methacrylate) (PMMA) particles. The fabric testing includes yarn pull-out, quasi-static spike puncture, and ballistic penetration resistance, performed on single fabric layers. It was found that both dry particle and STF treatments resulted in improvements in fabric properties relative to neat or poly(ethylene glycol) (PEG) treated fabrics. On comparison of treatments with different particle hardness, the SiO(2) materials performed better in all tests than comparable PMMA materials, although the SiO(2) treatments caused yarn failure in pull-out testing, reducing the total pull-out energy. In addition, resistance to yarn pull-out was found to be substantially higher for STF-treated fabrics than for dry particle treated fabrics. However, both dry particle addition and STF treatments exhibited comparable enhancements in puncture and ballistic resistance. These observations suggest that viscous stress transfer, friction, and physical entrainment of hard particles into filaments contribute to the demonstrated improvements in the properties of protective fabrics treated with shear thickening fluids.

  12. Analysis of Carbon Nanotube Pull-out from a Polymer Matrix

    NASA Technical Reports Server (NTRS)

    Frankland, S. J. V.; Harik, V. M.; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    Molecular dynamics (MD) simulations of carbon nanotube (NT) pull-out from a polymer matrix are carried out. As the NT pull-out develops in the simulation, variations in the displacement and velocities of the NT are monitored. The existence of a carbon-ring-based period in NT sliding during pull-out is identified. Linear trends in the NT velocity-force relation are observed and used to estimate an effective viscosity coefficient for interfacial sliding at the NT/polymer interface. As a result, the entire process of NT pull-out is characterized by an interfacial friction model that is based on a critical pull-out force, and an analog of Newton's friction law used to describe the NT/polymer interfacial sliding.

  13. [Design on tester of pull-out force for orthodontic micro implant].

    PubMed

    Su, He; Wu, Pei; Wang, Huiyuan; Chen, Yan; Bao, Xuemei

    2013-09-01

    A special device for measuring the pull-out force of orthodontic micro implant was designed, which has the characteristics of simple construction and easy operation, and can be used to detect the pull-out-force of orthodontic micro implant. The tested data was stored and analyzed by a computer, and as the results, the pull-out-force curve, maximum pull-out force as well as average pull-out force were outputted, which was applied in analyzing or investigating the initial stability and immediate loading property of orthodontic micro implant.

  14. Comparison of mechanical behavior between implant-simulated bone tissue and implant-jaw bone tissue interfaces based on Pull Out testing

    NASA Astrophysics Data System (ADS)

    Lopez, C.; Muñoz, J. C.; Pinillos, J. C.

    2013-11-01

    The main purpose of this research was to achieve a better understanding of the relationship within the mechanical properties of human cadaver jaw bone with kind D2 density regarding a substitute polymer to simulate bone tissue, proposed by the ASTM, to evaluate orthopedic implants. However, despite the existence of several densities of foams and his mechanical characterization has been classified into different degrees of tissue densities to simulate cancellous and cortical bone, the value of the densities are different contrasted with the densities of bone tissue, making difficult to establish direct relationship about mechanical behavior between the polymer and the bone material, and therefore no clear criteria known for choosing the polymeric foam which describes the mechanical behavior of tissue for a specific or particular study. To understand such behavior from bone tissue regarding the polymer samples, on this research was a dental implant inserted into the samples, and subjected to destructive Pull Out test according to ASTM F543The Pull Out strength was compared between implant-jawbone and implant-rigid polyurethane foam interfaces. Thus, the test pieces with mechanical behavior similar to bone tissue, enabling an approximation to choose degree appropriate of polymer to replace the bone tissue in future trials biomechanical.

  15. Nonlinear Deformation Behavior of New Braided Composites with Six-axis Yarn Orientations

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

    Ahn, H.-C.; Yu, W.-R.; Guo, Z.

    The braiding technology is one of fabrication methods that can produce three-dimensional fiber preforms. Braided composites have many advantages over other two-dimensional composites such as no delamination, high impact and fatigue properties, near-net shape preform, etc. Due to the undulated yarns in the braided preforms, however, their axial stiffness is lower than that of uni-directional or woven composites. To improve the axial stiffness, the longitudinal axial yarns were already introduced along with the braiding axis (five-axis braiding technology). In this study, we developed a new braided structure using six-axis braiding technology. In addition to braiding and longitudinal axial yarns, transversemore » axial yarn was introduced. New braided composites, so called six-axis braiding composites, were manufactured using ultra high molecular weight polyethylene and epoxy resin and their mechanical properties were characterized. To investigate the mechanical performance of these braided composites according to their manufacturing conditions, a numerical analysis was performed using their unit-cell modeling and finite element analysis. In the analysis the nonlinear deformation behavior will be included.« less

  16. Shear and friction between carbon nanotubes in bundles and yarns.

    PubMed

    Paci, Jeffrey T; Furmanchuk, Al'ona; Espinosa, Horacio D; Schatz, George C

    2014-11-12

    We perform a detailed density functional theory assessment of the factors that determine shear interactions between carbon nanotubes (CNTs) within bundles and in related CNT and graphene structures including yarns, providing an explanation for the shear force measured in recent experiments (Filleter, T. etal. Nano Lett. 2012, 12, 73). The potential energy barriers separating AB stacked structures are found to be irrelevant to the shear analysis for bundles and yarns due to turbostratic stacking, and as a result, the tube-tube shear strength for pristine CNTs is estimated to be <0.24 MPa, that is, extremely small. Instead, it is pinning due to the presence of defects and functional groups at the tube ends that primarily cause resistance to shear when bundles are fractured in weak vacuum (∼10(-5) Torr). Such defects and groups are estimated to involve 0.55 eV interaction energies on average, which is much larger than single-atom vacancy defects (approximately 0.039 eV). Furthermore, because graphitic materials are stiff they have large coherence lengths, and this means that push-pull effects result in force cancellation for vacancy and other defects that are internal to the CNTs. Another important factor is the softness of cantilever structures relative to the stiff CNTs in the experiments, as this contributes to elastic instability transitions that account for significant dissipation during shear that has been observed. The application of these results to the mechanical behavior of yarns is discussed, providing general guidelines for the manufacture of strong yarns composed of CNTs.

  17. Sensor yarns for real-time in situ detection of damage behavior for the purpose of structural health monitoring of textile-reinforced thermoset composites: development of a continuous wet-chemical silvering process for high-performance filament yarn

    NASA Astrophysics Data System (ADS)

    Onggar, T.; Häntzsche, E.; Nocke, A.; Hund, R. D.; Cherif, Ch

    2017-04-01

    High-performance textile yarns such as glass filament (GF) yarn will be used as the base material for the development of sensor yarns because glass filament yarns offer both high tensile strengths and moduli of elasticity, as well as high melting temperatures and elongation. A new continuous wet-chemical metallization process has been developed for GF yarns on a laboratory scale to achieve special properties such as electrical conductivity. The aim of the work is to develop a continuous wet-chemical silver plating process for the GF-filament yarn in order to achieve electrical conductivity on the GF-surface. The process was carried out continuously in order to metallize the GF, which is sensitive to the shear force. A homogeneous, completely covered and adhered silver layer on the GF yarn surfaces was obtained by the application of this technology. The surface morphology was been determined by light and scanning electron microscopy to assess the silver layer properties such as structure, homogeneity, and cracking. The chemical structure of the surfaces was analyzed by means of energy dispersive x-ray spectroscopy. For structural analysis, GF yarns were investigated using a Fourier transform infrared spectrometer. The dispersive and polar component of the surface energy of the sized and silvered GF yarn was measured by using a single fiber Tensiometer K100. The silver layer thickness and the silver content were determined after the metallization. Textile physical tests of the tensile strength, elasticity modulus, elongation at break, and yarn fineness of the single GF yarns as well as GF bundle were carried out.

  18. Effect of jute yarn on the mechanical behavior of concrete composites.

    PubMed

    Zakaria, Mohammad; Ahmed, Mashud; Hoque, Md Mozammel; Hannan, Abdul

    2015-01-01

    The objective of the study is to investigate the effect of introducing jute yarn on the mechanical properties of concrete. Jute fibre is produced abundantly in Bangladesh and hence, very cheap. The investigation on the enhancement of mechanical properties of concrete with jute yarn as reinforcement, if enhanced, will not only explore a way to improve the properties of concrete, it will also explore the use of jute and restrict the utilization of polymer which is environmentally detrimental. To accomplish the objective, an experimental investigation of the compressive, flexural and tensile strengths of Jute Yarn Reinforced Concrete composites (JYRCC) has been conducted. Cylinders, prisms and cubes of standard dimensions have been made to introducing jute yarn varying the mix ratio of the ingredients in concrete, water cement ratio, length and volume of yarn to know the effect of parameters as mentioned. Compressive, flexural and tensile strength tests had been conducted on the prepared samples by appropriate testing apparatus following Standards of tests. Mechanical properties of JYRCC were observed to be enhanced for a particular range of lengths of cut (10, 15, 20 and 25 mm) and volume content of jute yarn (0.1, 0.25, 0.5 and 0.75 %). The maximum increment of compressive, flexural and tensile strengths observed in the investigation are 33, 23 and 38 %, respectively with respect to concrete without jute yarn.

  19. RATE-DEPENDENT PULL-OUT BEARING CAPACITY OF PILES BY SIMILITUDE MODEL TESTS USING SEEPAGE FORCE

    NASA Astrophysics Data System (ADS)

    Kato, Tatsuya; Kokusho, Takaji

    Pull-out test of model piles was conducted by varying the pull-out velocity and skin friction of piles using a seepage force similitude model test apparatus. Due to the seepage consolidation under the pressure of 150kPa, the effective stress distribution in a prototype saturated soil of 17m could be successfully reproduced in the model ground of 28cm thick, in which the pull-out tests were carried out. The pull-out load rose to a peak value at small displacement, and then decreased to a residual value. At the same time, pore pressure in the vicinity of the pile decreased due to suction near the tip and the positive dilatancy near the pile skin. The maximum pull-out load, pile axial load, side friction and the corresponding displacement increased dramatically with increasing pull-out velocity. It was found that these rate-dependent trends become more prominent with increasing skin friction.

  20. In Vitro Evaluation and Mechanism Analysis of the Fiber Shedding Property of Textile Pile Debridement Materials

    PubMed Central

    Fu, Yijun; Xie, Qixue; Lao, Jihong; Wang, Lu

    2016-01-01

    Fiber shedding is a critical problem in biomedical textile debridement materials, which leads to infection and impairs wound healing. In this work, single fiber pull-out test was proposed as an in vitro evaluation for the fiber shedding property of a textile pile debridement material. Samples with different structural design (pile densities, numbers of ground yarns and coating times) were prepared and estimated under this testing method. Results show that single fiber pull-out test offers an appropriate in vitro evaluation for the fiber shedding property of textile pile debridement materials. Pull-out force for samples without back-coating exhibited a slight escalating trend with the supplement in pile density and number of ground yarn plies, while back-coating process significantly raised the single fiber pull-out force. For fiber shedding mechanism analysis, typical pull-out behavior and failure modes of the single fiber pull-out test were analyzed in detail. Three failure modes were found in this study, i.e., fiber slippage, coating point rupture and fiber breakage. In summary, to obtain samples with desirable fiber shedding property, fabric structural design, preparation process and raw materials selection should be taken into full consideration. PMID:28773428

  1. Yarn carrier with clutch

    NASA Technical Reports Server (NTRS)

    Doyne, Richard A. (Inventor); Benson, Rio H. (Inventor); El-Shiekh, Aly (Inventor)

    1994-01-01

    A yarn carrier apparatus particularly suited for use in braiding machinery or the like due to its capability of continuous yarn feeding and retraction of long lengths of yarn. The yarn carrier apparatus comprises a yarn supply spool which is rotatably mounted within the housing, a spring motor also mounted within the housing and operatively connected to the yarn supply spool through a mechanical transmission assembly which is adapted to multiply rotational movement between the first element of the gear assembly operatively connected to the spring motor and the final element of the gear assembly operatively connected to the yarn supply spool. The spring motor is adapted to tension the yarn during both feeding and retraction thereof, and it is further adapted to periodically rotatably slip within the housing and partially unwind so as to allow for continuous withdrawal of a long length of yarn without the spring motor becoming fully wound and preventing further yarn retraction.

  2. Development of Knitted Warm Garments from Speciality Jute Yarns

    NASA Astrophysics Data System (ADS)

    Roy, Alok Nath

    2013-09-01

    Jute-polyester blended core and textured polyester multifilament cover spun-wrapped yarn was produced using existing jute spinning machines. The spun-wrapped yarn so produced show a reduction in hairiness up to 86.1 %, improvement in specific work of rupture up to 9.8 % and specific flexural rigidity up to 23.6 % over ordinary jute-polyester blended yarn. The knitted swatch produced out of these spun-wrapped yarn using seven gauge and nine gauge needle in both single jersey and double jersey knitting machines showed very good dimensional stability even after three washing. The two-ply and three-ply yarn produced from single spun-wrapped yarn can be easily used in knitting machines and also in hand-knitting for the production of sweaters. The thermal insulation value of the sweaters produced with jute-polyester blended spun-wrapped yarn is comparable with thermal insulation value of sweaters made from 100 % acrylic and 100 % wool. However, the hand-knitted sweaters showed higher thermal insulation value than the machine-knitted sweaters due to less packing of yarn in hand knitted structure as compared to machine knitting.

  3. Characterization and Effects of Fiber Pull-Outs in Hole Quality of Carbon Fiber Reinforced Plastics Composite.

    PubMed

    Alizadeh Ashrafi, Sina; Miller, Peter W; Wandro, Kevin M; Kim, Dave

    2016-10-13

    Hole quality plays a crucial role in the production of close-tolerance holes utilized in aircraft assembly. Through drilling experiments of carbon fiber-reinforced plastic composites (CFRP), this study investigates the impact of varying drilling feed and speed conditions on fiber pull-out geometries and resulting hole quality parameters. For this study, hole quality parameters include hole size variance, hole roundness, and surface roughness. Fiber pull-out geometries are quantified by using scanning electron microscope (SEM) images of the mechanically-sectioned CFRP-machined holes, to measure pull-out length and depth. Fiber pull-out geometries and the hole quality parameter results are dependent on the drilling feed and spindle speed condition, which determines the forces and undeformed chip thickness during the process. Fiber pull-out geometries influence surface roughness parameters from a surface profilometer, while their effect on other hole quality parameters obtained from a coordinate measuring machine is minimal.

  4. POF-yarn weaves: controlling the light out-coupling of wearable phototherapy devices

    PubMed Central

    Quandt, Brit M.; Pfister, Marisa S.; Lübben, Jörn F.; Spano, Fabrizio; Rossi, René M.; Bona, Gian-Luca; Boesel, Luciano F.

    2017-01-01

    Neonatal jaundice (hyperbilirubinaemia) is common in neonates and, often, intensive blue-light phototherapy is required to prevent long-term effects. A photonic textile can overcome three major incubator-related concerns: Insulation of the neonate, human contact, and usage restraints. This paper describes the development of a homogeneous luminous textile from polymer optical fibres to use as a wearable, long-term phototherapy device. The bend out-coupling of light from the POFs was related to the weave production, e.g. weave pattern and yarn densities. Comfort, determined by friction against a skin model and breathability, was investigated additionally. Our textile is the first example of phototherapeutic clothing that is produced sans post-processing allowing for faster commercial production. PMID:29082067

  5. Characterization and Effects of Fiber Pull-Outs in Hole Quality of Carbon Fiber Reinforced Plastics Composite

    PubMed Central

    Alizadeh Ashrafi, Sina; Miller, Peter W.; Wandro, Kevin M.; Kim, Dave

    2016-01-01

    Hole quality plays a crucial role in the production of close-tolerance holes utilized in aircraft assembly. Through drilling experiments of carbon fiber-reinforced plastic composites (CFRP), this study investigates the impact of varying drilling feed and speed conditions on fiber pull-out geometries and resulting hole quality parameters. For this study, hole quality parameters include hole size variance, hole roundness, and surface roughness. Fiber pull-out geometries are quantified by using scanning electron microscope (SEM) images of the mechanically-sectioned CFRP-machined holes, to measure pull-out length and depth. Fiber pull-out geometries and the hole quality parameter results are dependent on the drilling feed and spindle speed condition, which determines the forces and undeformed chip thickness during the process. Fiber pull-out geometries influence surface roughness parameters from a surface profilometer, while their effect on other hole quality parameters obtained from a coordinate measuring machine is minimal. PMID:28773950

  6. Nanofiber-structured hydrogel yarns with pH-response capacity and cardiomyocyte-drivability for bio-microactuator application.

    PubMed

    Wu, Shaohua; Duan, Bin; Qin, Xiaohong; Butcher, Jonathan T

    2017-09-15

    Polymeric hydrogels have great potential in soft biological micro-actuator applications. However, inappropriate micro-architecture, non-anisotropy, weak biomechanics, and inferior response behaviors limit their development. In this study, we designed and manufactured novel polyacrylonitrile (PAN)-based hydrogel yarns composed with uniaxially aligned nanofibers. The nanofibrous hydrogel yarns possessed anisotropic architecture and robust mechanical properties with flexibility, and could be assembled into defined scaffold structures by subsequent processes. The as-prepared hydrogel yarns showed excellent pH response behaviors, with around 100% maximum length and 900% maximum diameter changes, and the pH response was completed within several seconds. Moreover, the hydrogel yarns displayed unique cell-responsive abilities to promote the cell adhesion, proliferation, and smooth muscle differentiation of human adipose derived mesenchymal stem cells (HADMSC). Chicken cardiomyocytes were further seeded onto our nanofibrous hydrogel yarns to engineer living cell-based microactuators. Our results demonstrated that the uniaxially aligned nanofibrous networks within the hydrogel yarns were the key characteristics leading to the anisotropic organization of cardiac cells, and improved sarcomere organization, mimicking the cardiomyocyte bundles in the native myocardium. The construct is capable of sustaining spontaneous cardiomyocyte pumping behaviors for 7days. Our PAN-based nanofibrous hydrogel yarns are attractive for creating linear microactuators with pH-response capacity and biological microactuators with cardiomyocyte-drivability. A mechanically robust polyacrylonitrile-based nanofibrous hydrogel yarn is fabricated by using a modified electrospinning setup in combination with chemical modification processes. The as-prepared hydrogel yarn possesses a uniaxially aligned nanofiber microarchitecture and supports a rapid, pH-dependent expansion/contraction response within a few

  7. Investigation of electrically conducting yarns for use in textile actuators

    NASA Astrophysics Data System (ADS)

    Martinez, Jose G.; Richter, Klaus; Persson, Nils-Krister; Jager, Edwin W. H.

    2018-07-01

    Textile actuators are an emerging technology to develop biomimetic actuators with synergetic actuation. They are composed of a passive fabric coated with an electroactive polymer providing with mechanical motion. Here we used different conducting yarns (polyamide + carbon, silicon + carbon, polyamide + silver coated, cellulose + carbon, polyester + 2 × INOX 50 μm, polyester + 2 × Cu/Sn and polyester + gold coated) to develop such textile actuators. It was possible to coat them through direct electrochemical methods, which should provide with an easier and more cost-effective fabrication process. The conductivity and the electrochemical properties of the yarns were sufficient to allow the electropolymerization of the conducting polymer polypyrrole on the yarns. The electropolymerization was carried out and both the linear and angular the actuation of the yarns was investigated. These yarns may be incorporated into textile actuators for assistive prosthetic devices easier and cheaper to get and at the same time with good mechanical performance are envisaged.

  8. Analysis of Effect of Rolling Pull-Outs on Wing and Aileron Loads of a Fighter Airplane

    NASA Technical Reports Server (NTRS)

    Pearson, Henry A.; Aiken, William S.

    1946-01-01

    An analysis was made to determine the effect of rolling pull-out maneuvers on the wing and aileron loads of a typical fighter airplane, the P-47B. The results obtained indicate that higher loads are imposed upon wings and ailerons because of the rolling pull-out maneuver, than would be obtained by application of the loading requirements to which the airplane was designed. An increase of 102 lb or 15 percent of wing weight would be required if the wing were designed for rolling pull-out maneuver. It was also determined that the requirements by which the aileron was originally designed were inadequate.

  9. Additive manufactured push-fit implant fixation with screw-strength pull out.

    PubMed

    van Arkel, Richard J; Ghouse, Shaaz; Milner, Piers E; Jeffers, Jonathan R T

    2017-10-11

    Additive manufacturing offers exciting new possibilities for improving long-term metallic implant fixation in bone through enabling open porous structures for bony ingrowth. The aim of this research was to investigate how the technology could also improve initial fixation, a precursor to successful long-term fixation. A new barbed fixation mechanism, relying on flexible struts was proposed and manufactured as a push-fit peg. The technology was optimized using a synthetic bone model and compared with conventional press-fit peg controls tested over a range of interference fits. Optimum designs, achieving maximum pull-out force, were subsequently tested in a cadaveric femoral condyle model. The barbed fixation surface provided more than double the pull-out force for less than a third of the insertion force compared to the best performing conventional press-fit peg (p < 0.001). Indeed, it provided screw-strength pull out from a push-fit device (1,124 ± 146 N). This step change in implant fixation potential offers new capabilities for low profile, minimally invasive implant design, while providing new options to simplify surgery, allowing for one-piece push-fit components with high levels of initial stability. © 2017 The Authors. Journal of Orthopaedic Research Published by WileyPeriodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 9999:1-11, 2017. © 2017 The Authors. Journal of Orthopaedic Research Published by WileyPeriodicals, Inc. on behalf of the Orthopaedic Research Society.

  10. Influence of cement compressive strength and porosity on augmentation performance in a model of orthopedic screw pull-out.

    PubMed

    Pujari-Palmer, Michael; Robo, Celine; Persson, Cecilia; Procter, Philip; Engqvist, Håkan

    2018-01-01

    Disease and injuries that affect the skeletal system may require surgical intervention and internal fixation, i.e. orthopedic plate and screw insertion, to stabilize the injury and facilitate tissue repair. If the surrounding bone quality is poor the screws may migrate, or the bone may fail, resulting in fixation failure. While numerous studies have shown that cement augmentation of the interface between bone and implant can increase screw pull-out force, the physical properties of cement that influence pull-out force have not been investigated. The present study sought to determine how the physical properties of high strength calcium phosphate cements (hsCPCs, specifically dicalcium phosphate) affected the corresponding orthopedic screw pull-out force in urethane foam models of "healthy" and "osteoporotic" synthetic bone (Sawbones). In the simplest model, where only the bond strength between screw thread and cement (without Sawbone) was tested, the correlation between pull-out force and cement compressive strength (R 2 = 0.79) was weaker than correlation with total cement porosity (R 2 = 0.89). In open pore Sawbone that mimics "healthy" cancellous bone density the stronger cements produced higher pull-out force (50-60% increase). High strength, low porosity cements also produced higher pull-out forces (50-190% increase) in "healthy" Sawbones with cortical fixation if the failure strength of the cortical material was similar to, or greater than (a metal shell), actual cortical bone. This result is of particular clinical relevance where fixation with a metal plate implant is indicated, as the nearby metal can simulate a thicker cortical shell, thereby increasing the pull-out force of screws augmented with stronger cements. The improvement in pull-out force was apparent even at low augmentation volumes of 0.5mL (50% increase), which suggest that in clinical situations where augmentation volume is limited the stronger, lower porosity calcium phosphate cement (CPC) may

  11. Inclusion at Risk? Push- and Pull-Out Phenomena in Inclusive School Systems: The Italian and Norwegian Experiences

    ERIC Educational Resources Information Center

    Nes, Kari; Demo, Heidrun; Ianes, Dario

    2018-01-01

    The main objective of this article is to explore and compare research data on pull-out and push-out phenomena within inclusive school systems, discussing if and how they represent a risk for inclusion. The terms pull-out and push-out refer to situations in which some groups of students in regular schools learn in settings apart from their peers.…

  12. Double transosseous pull out suture technique for transection of posterior horn of medial meniscus.

    PubMed

    Ahn, Jin Hwan; Wang, Joon Ho; Lim, Hong Chul; Bae, Ji Hoon; Park, Joon Soo; Yoo, Jae Chul; Shyam, Ashok Kumar

    2009-03-01

    Transection injury (complete radial tear, root tear) in the posterior horn of medial meniscus will lead to loss of hoop strain, extrusion of the meniscus and early degenerative changes. The posterior horn of medial meniscus is amenable to repair due to its good blood supply and repair is the procedure of choice for these injuries. In cases of transection of the medial meniscus posterior horn, the meniscus can be repaired by a pull out suture technique using trans-septal portal. The single transosseous pull out suturing technique is a point fixation technique with limited contact area having low and inhomogeneous contact pressure. This article describes a double transosseous pull out suture technique using trans-septal portal for the repair of transection of posterior horn of medial meniscus. Use of double transosseous technique provides more secure fixation, more homogeneous and wider contact pressure area between meniscus and the bone, improving the healing potential of the repair.

  13. Biomechanical evaluation of a transtibial pull-out meniscal root repair: challenging the bungee effect.

    PubMed

    Cerminara, Anthony J; LaPrade, Christopher M; Smith, Sean D; Ellman, Michael B; Wijdicks, Coen A; LaPrade, Robert F

    2014-12-01

    A common treatment for posterior meniscal root tears is transtibial pull-out repair, which has been biomechanically reported to restore tibiofemoral contact mechanics to those of the intact knee. Biomechanical data suggest that there is significant displacement of the repaired meniscal root with cyclic loading, which may be responsible for the poor healing and meniscal extrusion demonstrated in some clinical studies. The purpose of this study was to quantify the time-zero displacement of the posterior meniscal root in response to cyclic loading after transtibial pull-out repair and to quantify the individual contributions to displacement of the following: (1) suture elongation, (2) button-bone interface, and (3) meniscus-suture interface. The meniscus-suture interface was hypothesized to result in significantly more displacement than the button-bone interface or suture elongation. Descriptive laboratory study. Transtibial pull-out repair of the posterior medial meniscal root was performed in 6 porcine knees, and cyclic displacement was measured using a loading protocol representative of postoperative rehabilitation. Displacement from (1) suture elongation, (2) the button-bone interface, and (3) the meniscus-suture interface was determined by cyclically loading 6 specimens for each construct using the same loading protocol to determine the contribution of each component to the overall displacement of the repair construct. After 1000 cycles, the repair construct displaced by a mean of 3.28 mm (95% CI, 2.07-4.49). The meniscus-suture component (mean, 2.52 mm; 95% CI, 2.21-2.83) displaced significantly more than the button-bone component (mean, 0.90 mm; 95% CI, 0.64-1.15; P = .006) and suture elongation component (mean, 0.71 mm; 95% CI, 0.36-1.06; P = .006) after 1000 cycles. Displacement of the button-bone and suture elongation components was not significantly different after 1000 cycles (P = .720). There was substantial displacement of the posterior medial meniscal

  14. Stiffness and Poisson ratio in longitudinal compression of fiber yarns in meso-FE modelling of composite reinforcement forming

    NASA Astrophysics Data System (ADS)

    Wang, D.; Naouar, N.; Vidal-Salle, E.; Boisse, P.

    2018-05-01

    In meso-scale finite element modeling, the yarns of the reinforcement are considered to be solids made of a continuous material in contact with their neighbors. The present paper consider the mechanical behavior of these yarns that can happen for some loadings of the reinforcement. The yarns present a specific mechanical behavior when under longitudinal compression because they are made up of a large number of fibers, Local buckling of the fibers causes the compressive stiffness of the continuous material representing the yarn to be much weaker than when under tension. In addition, longitudinal compression causes an important transverse expansion. It is shown that the transverse expansion can be depicted by a Poisson ratio that remained roughly constant when the yarn length and the compression strain varied. Buckling of the fibers significantly increases the transverse dimensions of the yarn which leads to a large Poisson ratio (up to 12 for a yarn analyzed in the present study). Meso-scale finite element simulations of reinforcements with binder yarns submitted to longitudinal compression showed that these improvements led to results in good agreement with micro-CT analyses.

  15. Elastic Response and Failure Studies of Multi-Wall Carbon Nanotube Twisted Yarns

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.; Jefferson, Gail D.; Frankland, Sarah-Jane V.

    2007-01-01

    Experimental data on the stress-strain behavior of a polymer multiwall carbon nanotube (MWCNT) yarn composite are used to motivate an initial study in multi-scale modeling of strength and stiffness. Atomistic and continuum length scale modeling methods are outlined to illustrate the range of parameters required to accurately model behavior. The carbon nanotubes yarns are four-ply, twisted, and combined with an elastomer to form a single-layer, unidirectional composite. Due to this textile structure, the yarn is a complicated system of unique geometric relationships subjected to combined loads. Experimental data illustrate the local failure modes induced by static, tensile tests. Key structure-property relationships are highlighted at each length scale indicating opportunities for parametric studies to assist the selection of advantageous material development and manufacturing methods.

  16. Investigation of the technology of conductive yarns manufacturing

    NASA Astrophysics Data System (ADS)

    Ryklin, Dzmitry; Medvetski, Sergey

    2017-10-01

    The paper is devoted to development of technology of electrically conductive yarn production. This technology allows manufacturing conductive yarns of copper wire and polyester filament yarns. Method of the predicting of the conductive yarn breaking force was developed on the base of analysing of load-elongation curves of each strand of the yarn. Also the method of the predicting of the conductive yarn diameter was offered. Investigation shows that conductive yarns can be integrated into the textiles structure using sewing or embroidery equipment. Application of developed conductive yarn is wearable electronics creating with wide range of functions, for example, for specific health issue monitoring, navigation tools or communication gadgets.

  17. Establishment of a new pull-out strength testing method to quantify early osseointegration-An experimental pilot study.

    PubMed

    Nonhoff, J; Moest, T; Schmitt, Christian Martin; Weisel, T; Bauer, S; Schlegel, K A

    2015-12-01

    The animal study aims to evaluate a new experimental model for measuring sole the influence of the surface characteristics independent from implant macro-design on the level of osseointegration by registering the pull-out strength needed for removal of experimental devices with different surfaces from artificial defects. Seventy-two test bodies (36 with the FRIADENT(®) plus surface, 36 with the P15/HAp biofunctionalized surface) were inserted in six adult domestic pigs with artificial calvarial defects. The experimental devices were designed to fit in the defects leaving a gap between the test body and the local bone. After 21 days of healing, the animals were sacrificed and the test bodies were pulled out with a standardised reproducible pull-out device measuring the pull-out strength. The pull-out strength for both groups was compared. Twenty-one days after insertion a mean force of 412 ± 142 N for the P15/HAp group and 183 ± 105 N for the FRIADENT(®) plus group was measured for the removal of the specimens from the calvarial bone. The difference between the groups was statistically significant (p < 0.0001). The experimental set-up seems to be a suitable method when measuring the impact of implant surfaces on the early stage of osseointegration. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  18. High-Performance Supercapacitors from Niobium Nanowire Yarns.

    PubMed

    Mirvakili, Seyed M; Mirvakili, Mehr Negar; Englezos, Peter; Madden, John D W; Hunter, Ian W

    2015-07-01

    The large-ion-accessible surface area of carbon nanotubes (CNTs) and graphene sheets formed as yarns, forests, and films enables miniature high-performance supercapacitors with power densities exceeding those of electrolytics while achieving energy densities equaling those of batteries. Capacitance and energy density can be enhanced by depositing highly pseudocapacitive materials such as conductive polymers on them. Yarns formed from carbon nanotubes are proposed for use in wearable supercapacitors. In this work, we show that high power, energy density, and capacitance in yarn form are not unique to carbon materials, and we introduce niobium nanowires as an alternative. These yarns show higher capacitance and energy per volume and are stronger and 100 times more conductive than similarly spun carbon multiwalled nanotube (MWNT) and graphene yarns. The long niobium nanowires, formed by repeated extrusion and drawing, achieve device volumetric peak power and energy densities of 55 MW·m(-3) (55 W·cm(-3)) and 25 MJ·m(-3) (7 mWh·cm(-3)), 2 and 5 times higher than that for state-of-the-art CNT yarns, respectively. The capacitance per volume of Nb nanowire yarn is lower than the 158 MF·m(-3) (158 F·cm(-3)) reported for carbon-based materials such as reduced graphene oxide (RGO) and CNT wet-spun yarns, but the peak power and energy densities are 200 and 2 times higher, respectively. Achieving high power in long yarns is made possible by the high conductivity of the metal, and achievement of high energy density is possible thanks to the high internal surface area. No additional metal backing is needed, unlike for CNT yarns and supercapacitors in general, saving substantial space. As the yarn is infiltrated with pseudocapacitive materials such as poly(3,4-ethylenedioxythiophene) (PEDOT), the energy density is further increased to 10 MJ·m(-3) (2.8 mWh·cm(-3)). Similar to CNT yarns, niobium nanowire yarns are highly flexible and show potential for weaving into textiles

  19. Effect of various factors on pull out strength of pedicle screw in normal and osteoporotic cancellous bone models.

    PubMed

    Varghese, Vicky; Saravana Kumar, Gurunathan; Krishnan, Venkatesh

    2017-02-01

    Pedicle screws are widely used for the treatment of spinal instability by spine fusion. Screw loosening is a major problem of spine fusion, contributing to delayed patient recovery. The present study aimed to understand the factor and interaction effects of density, insertion depth and insertion angle on pedicle screw pull out strength and insertion torque. A pull out study was carried out on rigid polyurethane foam blocks representing osteoporotic to normal bone densities according to the ASTM-1839 standard. It was found that density contributes most to pullout strength and insertion torque. The interaction effect is significant (p < 0.05) and contributes 8% to pull out strength. Axial pullout strength was 34% lower than angled pull out strength in the osteoporotic bone model. Insertion angle had no significant effect (p > 0.05) on insertion torque. Pullout strength and insertion torque had no significant correlation (p > 0.05) in the case of the extremely osteoporotic bone model. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  20. YARNsim: Simulating Hadoop YARN

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

    Liu, Ning; Yang, Xi; Sun, Xian-He

    Despite the popularity of the Apache Hadoop system, its success has been limited by issues such as single points of failure, centralized job/task management, and lack of support for programming models other than MapReduce. The next generation of Hadoop, Apache Hadoop YARN, is designed to address these issues. In this paper, we propose YARNsim, a simulation system for Hadoop YARN. YARNsim is based on parallel discrete event simulation and provides protocol-level accuracy in simulating key components of YARN. YARNsim provides a virtual platform on which system architects can evaluate the design and implementation of Hadoop YARN systems. Also, application developersmore » can tune job performance and understand the tradeoffs between different configurations, and Hadoop YARN system vendors can evaluate system efficiency under limited budgets. To demonstrate the validity of YARNsim, we use it to model two real systems and compare the experimental results from YARNsim and the real systems. The experiments include standard Hadoop benchmarks, synthetic workloads, and a bioinformatics application. The results show that the error rate is within 10% for the majority of test cases. The experiments prove that YARNsim can provide what-if analysis for system designers in a timely manner and at minimal cost compared with testing and evaluating on a real system.« less

  1. A comparative study on cotton fiber length parameters’ effects on modeling yarn property

    USDA-ARS?s Scientific Manuscript database

    Fiber length is one of the key properties of cotton and has important influences on yarn production and yarn quality. Various parameters have been developed to characterize cotton fiber length in the past decades. This study was carried out to investigate the effects of these parameters and their ...

  2. Processing mechanics of alternate twist ply (ATP) yarn technology

    NASA Astrophysics Data System (ADS)

    Elkhamy, Donia Said

    Ply yarns are important in many textile manufacturing processes and various applications. The primary process used for producing ply yarns is cabling. The speed of cabling is limited to about 35m/min. With the world's increasing demands of ply yarn supply, cabling is incompatible with today's demand activated manufacturing strategies. The Alternate Twist Ply (ATP) yarn technology is a relatively new process for producing ply yarns with improved productivity and flexibility. This technology involves self plying of twisted singles yarn to produce ply yarn. The ATP process can run more than ten times faster than cabling. To implement the ATP process to produce ply yarns there are major quality issues; uniform Twist Profile and yarn Twist Efficiency. The goal of this thesis is to improve these issues through process modeling based on understanding the physics and processing mechanics of the ATP yarn system. In our study we determine the main parameters that control the yarn twist profile. Process modeling of the yarn twist across different process zones was done. A computational model was designed to predict the process parameters required to achieve a square wave twist profile. Twist efficiency, a measure of yarn torsional stability and bulk, is determined by the ratio of ply yarn twist to singles yarn twist. Response Surface Methodology was used to develop the processing window that can reproduce ATP yarns with high twist efficiency. Equilibrium conditions of tensions and torques acting on the yarns at the self ply point were analyzed and determined the pathway for achieving higher twist efficiency. Mechanistic modeling relating equilibrium conditions to the twist efficiency was developed. A static tester was designed to zoom into the self ply zone of the ATP yarn. A computer controlled, prototypic ATP machine was constructed and confirmed the mechanistic model results. Optimum parameters achieving maximum twist efficiency were determined in this study. The

  3. Multifunctional Characteristics of Carbon Nanotube (CNT) Yarn Composites

    NASA Technical Reports Server (NTRS)

    Hernandez, Corey D.; Zhang, Mei; Fang, Shaoli; Baughman, Ray H.; Gates, Thomas S.; Kahng, Seun K.

    2006-01-01

    By forming composite structures with Carbon Nanotube (CNT) yarns we achieve materials capable of measuring strain and composite structures with increased mechanical strength. The CNT yarns used are of the 2-ply and 4-ply variety with the yarns having diameters of about 15-30 micrometers. The strain sensing characteristics of the yarns are investigated on test beams with the yarns arranged in a bridge configuration. Additionally, the strain sensing properties are also investigated on yarns embedded on the surface of a flexible membrane. Initial mechanical strength tests also show an increase in the modulus of elasticity of the composite materials while incurring a weight penalty of less than one-percent. Also presented are initial temperature characterizations of the yarns.

  4. Biomechanical Comparisons of Pull Out Strengths After Pedicle Screw Augmentation with Hydroxyapatite, Calcium Phosphate, or Polymethylmethacrylate in the Cadaveric Spine.

    PubMed

    Yi, Seong; Rim, Dae-Cheol; Park, Seoung Woo; Murovic, Judith A; Lim, Jesse; Park, Jon

    2015-06-01

    In vertebrae with low bone mineral densities pull out strength is often poor, thus various substances have been used to fill screw holes before screw placement for corrective spine surgery. We performed biomechanical cadaveric studies to compare nonaugmented pedicle screws versus hydroxyapatite, calcium phosphate, or polymethylmethacrylate augmented pedicle screws for screw tightening torques and pull out strengths in spine procedures requiring bone screw insertion. Seven human cadaveric T10-L1 spines with 28 vertebral bodies were examined by x-ray to exclude bony abnormalities. Dual-energy x-ray absorptiometry scans evaluated bone mineral densities. Twenty of 28 vertebrae underwent ipsilateral fluoroscopic placement of 6-mm holes augmented with hydroxyapatite, calcium phosphate, or polymethylmethacrylate, followed by transpedicular screw placements. Controls were pedicle screw placements in the contralateral hemivertebrae without augmentation. All groups were evaluated for axial pull out strength using a biomechanical loading frame. Mean pedicle screw axial pull out strength compared with controls increased by 12.5% in hydroxyapatite augmented hemivertebrae (P = 0.600) and by 14.9% in calcium phosphate augmented hemivertebrae (P = 0.234), but the increase was not significant for either method. Pull out strength of polymethylmethacrylate versus hydroxyapatite augmented pedicle screws was 60.8% higher (P = 0.028). Hydroxyapatite and calcium phosphate augmentation in osteoporotic vertebrae showed a trend toward increased pedicle screw pull out strength versus controls. Pedicle screw pull out force of polymethylmethacrylate in the insertion stage was higher than that of hydroxyapatite. However, hydroxyapatite is likely a better clinical alternative to polymethylmethacrylate, as hydroxyapatite augmentation, unlike polymethylmethacrylate augmentation, stimulates bone growth and can be revised. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Yarn carrier apparatus for braiding machines and the like

    NASA Technical Reports Server (NTRS)

    El-Shiekh, Aly (Inventor); Li, Wei (Inventor); Hammad, Mohamed (Inventor)

    1992-01-01

    A yarn carrier apparatus particularly suited for use in braiding machinery or the like due to its capability of continuous yarn feeding and retraction of long lengths of yarn. The yarn carrier apparatus comprises a yarn supply spool which is rotatably mounted within the housing, a spring motor also mounted within the housing and operatively connected to the yarn supply spool through a mechanical transmission assembly which is adapted to multiply rotational movement between the first element of the gear assembly operatively connected to the spring motor and the final element of the gear assembly operatively connected to the yarn supply spool. The spring motor is adapted to tension the yarn during both feeding and retraction thereof, and it is further adapted to periodically rotatably slip within the housing and partially unwind so as to allow for continuous withdrawal of a long length of yarn without the spring motor becoming fully wound and preventing further yarn retraction.

  6. Assessment of the RIVET fixation system for cranioplasty using the pull-out technique.

    PubMed

    Sakamoto, Yoshiaki; Minabe, Toshiharu; Kato, Tatsuya; Kishi, Kazuo

    2015-03-01

    Cranioplasty using custom-made hydroxyapatite (HAP) ceramic implants is a common procedure to repair skull defects. However, commercially available titanium screws are only minimally stabilized due to characteristic brittleness. We developed the RIVET technique which involves fixing a bioabsorbable plate atop a HAP block using bioabsorbable screws extending beyond both layers, and evaluated fixation strength using the pull-out test and microtomography. Three experimental conditions were compared: a non-RIVET group, RIVET group, and dry skull control group. Pull-out strength significantly differed across groups (non-RIVET group, 1.33 ± 1.21 kgf; RIVET group, 4.46 ± 0.84 kgf; and control group, 6.99 ± 1.14 kgf, P < 0.01). Microtomography of the dry skull control group revealed thread grooves fitted to the screws. The non-RIVET and RIVET groups presented fewer thread grooves than the control group, and the screws did not fit perfectly to the HAP block. However, fixation in the RIVET group was more stable, as the rivet was firmly lodged into the implant. In conclusion, by melting and creating the rivet, pull-out strength can be increased and rigid stabilization of HAP can be obtained. This technique uses commercially available absorbable plate and screws, and thus can be used widely in clinical applications involving HAP blocks with different porosities and thicknesses. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  7. Mesoscale mechanics of twisting carbon nanotube yarns.

    PubMed

    Mirzaeifar, Reza; Qin, Zhao; Buehler, Markus J

    2015-03-12

    Fabricating continuous macroscopic carbon nanotube (CNT) yarns with mechanical properties close to individual CNTs remains a major challenge. Spinning CNT fibers and ribbons for enhancing the weak interactions between the nanotubes is a simple and efficient method for fabricating high-strength and tough continuous yarns. Here we investigate the mesoscale mechanics of twisting CNT yarns using full atomistic and coarse grained molecular dynamics simulations, considering concurrent mechanisms at multiple length-scales. To investigate the mechanical response of such a complex structure without losing insights into the molecular mechanism, we applied a multiscale strategy. The full atomistic results are used for training a coarse grained model for studying larger systems consisting of several CNTs. The mesoscopic model parameters are updated as a function of the twist angle, based on the full atomistic results, in order to incorporate the atomistic scale deformation mechanisms in larger scale simulations. By bridging across two length scales, our model is capable of accurately predicting the mechanical behavior of twisted yarns while the atomistic level deformations in individual nanotubes are integrated into the model by updating the parameters. Our results focused on studying a bundle of close packed nanotubes provide novel mechanistic insights into the spinning of CNTs. Our simulations reveal how twisting a bundle of CNTs improves the shear interaction between the nanotubes up to a certain level due to increasing the interaction surface. Furthermore, twisting the bundle weakens the intertube interactions due to excessive deformation in the cross sections of individual CNTs in the bundle.

  8. Posterior Meniscal Root Repairs: Outcomes of an Anatomic Transtibial Pull-Out Technique.

    PubMed

    LaPrade, Robert F; Matheny, Lauren M; Moulton, Samuel G; James, Evan W; Dean, Chase S

    2017-03-01

    Outcomes after transtibial pull-out repair for posterior meniscal root tears remain underreported, and factors that may affect outcomes are unknown. Purpose/Hypothesis: The purpose of this study was to compare patient-centered outcomes after transtibial pull-out repair for posterior root tears in patients <50 and ≥50 years of age. We hypothesized that improvement in function and activity level at minimum 2-year follow-up would be similar among patients <50 years of age compared with patients ≥50 years and among patients undergoing medial versus lateral root repairs. Cohort study; Level of evidence, 3. Inclusion criteria were patients aged 18 years or older who underwent anatomic transtibial pull-out repair of the medial or lateral posterior meniscus root by a single surgeon. All patients were identified from a data registry consisting of prospectively collected data in a consecutive series. Cohorts were analyzed by age (<50 years [n = 35] vs ≥50 years [n = 15]) and laterality (lateral [n = 15] vs medial [n = 35]). Patients completed a subjective questionnaire preoperatively and at minimum of 2 years postoperatively (Lysholm, Tegner, Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], 12-Item Short Form Health Survey [SF-12], and patient satisfaction with outcome). Failure was defined as revision meniscal root repair or partial meniscectomy. The analysis included 50 knees in 49 patients (16 females, 33 males; mean age, 38.3 years; mean body mass index, 26.6). Of the 50 knees, 45 were available for analysis. Three of 45 (6.7%) required revision surgery. All failures were in patients <50 years old, and all failures underwent medial root repair. No significant difference in failure was found based on age ( P=.541) or laterality ( P = .544). For age cohorts, Lysholm and WOMAC scores demonstrated significant postoperative improvement. For laterality cohorts, all functional scores significantly improved postoperatively. No significant difference

  9. A pull out test to compare two riparian species, Phyllanthus sellowianus and Sebastiania schottiana in terms of root anchorage ability

    NASA Astrophysics Data System (ADS)

    Hörbinger, Stephan; Sutili, Fabricio J.; Rauch, Hans Peter

    2013-04-01

    Soil bioengineering has become manifold applied in large parts of Brazil in recent years. The first projects were realized in the region of Rio Grande do Sul within river stabilization works to protect agricultural land of small regional farmers. As result of research work the species Sebastiania schottiana and Phyllanthus sellowianus showed very adequate morpho-physiological properties and seem to be appropriate for the use in soil bioengineering. The aim of the present study was to examine a still unknown but crucial factor, the resistance of the above mentioned species against being pulled out. The pull out resistance is an indicator for the stability of the soil-root matrix and expresses the stabilizing effects of plants on soil. Furthermore it is an applicable index to compare the qualification of the species to be used in soil bioengineering works. Another objective was to investigate plant characteristics, which correlate to the pull out resistance of the investigated species, to be able to draft up efficient plant strategies for future restoration works on eroded river embankments. For the experiment a special apparatus was designed, which enables to implement a pull out process with a constant rate and generate a graph of the plants resistance force versus its displacement. P. sellowianus showed a significant higher resistance against being pulled out than S. schottiana. The analyses of root and shoot properties of P. sellowianus showed more favorable morpho-physiological properties in terms of pull out resistance, a bigger amount of biomass, both above and below ground and also a higher amount of anchorage. The Cross-Sectional-Areas (CSA) of the shoots showed in both species the strongest correlation of the investigated shoot and root properties with the maximum resistance against being pulled out. Thus it can be concluded that the CSA can be used as a value to assess the stabilization effects of the plants. The experiments showed that some root and shoot

  10. Numerical and experimental analyses of out-of-plane deformation of triaxial woven fabric

    NASA Astrophysics Data System (ADS)

    Zhou, Hongtao; Xiao, Xueliang; Qian, Kun; Zhang, Kun; Zhang, Diantang

    2018-05-01

    With three sets of yarns interwoven in plane for angle-interlock structure, triaxial woven fabric (TWF) is a unique and perfect construction material for products subjected to multi-directional loads, as compared to classic fabrics of orthogonal structure. Finite-element analysis (FEA) and experimental methods are applied to study the out-of-plane deformation (OPD) behaviors of TWF and plain woven fabric (PWF). Among this, the yarn cross section, path and woven structure are obtained using optical microscopy, the related parameters are input to finite element model (FEM) for simulating the OPD behavior. This paper presents a detailed analysis on out-of-plane deformation behavior of TWF and PWF by the finite element method and experiment. In consideration of the comparability, TWF and PWF are designed and prepared with the same yarns and areal density (g/m2). The deformation profile, maximum stress and maximum deflection of TWF and PWF are obtained by FEA and experiment. It has been found that the maximum deflection and maximum stress of TWF is smaller than that of PWF under the same uniform negative pressure, both FEA and experiment. Furthermore, the stress distribution of TWF is more evenly than that of PWF, indicating that TWF exhibited superior isotropy in comparison with PWF for one more directional set of yarns in undertaking the OPD.

  11. Development of novel textile and yarn actuators using plasticized PVC gel

    NASA Astrophysics Data System (ADS)

    Furuse, A.; Hashimoto, M.

    2017-04-01

    Soft actuators based on polymers are expected to be used for power sources to drive wearable robots which required in a wide range of fields such as medical, care and welfare, because they are light weight, flexible and quiet. Plasticized PVC gel which has a large deformation by applying a voltage and high driving stability in the atmosphere is considered as a suitable candidate material for development of soft actuator. Then, we proposed two kinds of novel flexible actuators constructed like yarn and textile by using plasticized PVC gel to develop soft actuator to realize a higher flexibility and low-voltage driving. In this study, we prepared prototypes of these actuators and clarify their characteristic. In addition, we considered the deformation model from its characteristics and geometric calculation. When a voltage was applied to their actuators, textile type actuator was contracted, while the twisted yarn type actuator was expanded. The deformation behavior of the proposed actuators could be found at a low voltage of 200V, the contraction strain of the textile actuator was about 27 %, and the expanding ratio of the yarn actuator was 0.4 %. Maximum contraction strain of textile actuator and expansion ratio of yarn actuator was 53% and 1.4% at 600 V, respectively. The calculation results from the proposed model were in roughly agreement with the experimental values. It indicated that deformation behavior of these actuators could estimate from models.

  12. Piezoelectric antibacterial fabric comprised of poly(l-lactic acid) yarn

    NASA Astrophysics Data System (ADS)

    Ando, Masamichi; Takeshima, Satoshi; Ishiura, Yutaka; Ando, Kanako; Onishi, Osamu

    2017-10-01

    A lactic acid monomer has an asymmetric carbon in the molecule, so there are optical isomer l- and d-type. The most widely used poly(lactic acid) (PLA) for commercial applications is poly(l-lactic acid) (PLLA). PLLA is the polymerization product of l-lactide. Certain treatments of PLLA can yield a film that exhibits shear piezoelectricity. Thus, piezoelectric PLLA fiber can be generated by micro slitting piezoelectric PLLA films or by a melt spinning method. We prepared left-handed helical multi fiber yarn (S-yarn) and right-handed helical yarn (Z-yarn) using piezoelectric PLLA fiber. PLLA exhibited shear mode piezoelectricity, causing the electric polarity of the yarn surface to be reversed on the S-yarn and Z-yarn when tension was applied. An SZ-yarn was produced by combining the S-yarn and Z-yarn, and fabric was prepared using the SZ-yarn. This study demonstrated that the fabric has a strong antibacterial effect, which is thought to be due to the strong electric field between the yarns. The field is generated by a piezoelectric effect when the fabric was extended and contracted.

  13. Study on the Filament Yarns Spreading Techniques and Assessment Methods of the Electronic Fiberglass Fabric

    NASA Astrophysics Data System (ADS)

    Wang, Xi; Chen, Shouhui; Zheng, Tianyong; Ning, Xiangchun; Dai, Yifei

    2018-03-01

    The filament yarns spreading techniques of electronic fiberglass fabric were developed in the past few years in order to meet the requirements of the development of electronic industry. Copper clad laminate (CCL) requires that the warp and weft yarns of the fabric could be spread out of apart and formed flat. The penetration performance of resin could be improved due to the filament yarns spreading techniques of electronic fiberglass fabric, the same as peeling strength of CCL and drilling performance of printed circuit board (PCB). This paper shows the filament yarns spreading techniques of electronic fiberglass fabric from several aspects, such as methods and functions, also with the assessment methods of their effects.

  14. Characterization of Multifunctional Carbon Nanotube Yarns: In-situ Strain Sensing and Composite Reinforcement

    NASA Astrophysics Data System (ADS)

    Page, Christian David

    A large body of scientific research and development worldwide has focused on the unprecedented structural/functional properties of carbon nanotubes (CNT), yet translation of these unique properties of CNTs to macroscopic materials has been slow to develop. CNT yarns are an appealing application for CNTs; their lightweight and small diameter can allow for them to be embedded into composite materials. Since the individual nanotubes have shown to have incredibly high strength, stiffness, and strain sensitivity, CNT yarns have the potential to be highly effective for in-situ structural health monitoring of advanced materials and structures. This work identifies the sources for losses in strength and electromechanical sensitivity. This is done by first understanding the physics involved with a CNT yarn under axial strain. Since this material is not a Newtonian solid, the stress-strain relationships are dissimilar to conventional materials, exhibiting a three zone behavior. This is present in both the stress-strain and resistance-strain relationships. A tensile test performed in-situ within a scanning electron microscope showed that the diameter of the yarn reduced greatly during tension, which indicates that the volume is not constant; therefore, the intratube/intrabundle load transfer efficiency and electrical conductivity change significantly under strain. Observation of this phenomenon helps elucidate the source for loss in the translation from nanoscopic CNTs to the macroscopic CNT yarns. Following the observation that the CNT yarn is not a solid body mechanics system, investigation into the long-standing field of textile engineering helped to identify that the CNT yarn structural hierarchy should be re-evaluated. Literary review reveals that the predominant base morphology of CNT yarns is bundles of CNTs as opposed to individual CNTs. Furthermore, in conventional textiles, it is well known that the base morphology (in textiles this is the "fiber") will bundle

  15. High-performance two-ply yarn supercapacitors based on carbon nanotube yarns dotted with Co3 O4 and NiO nanoparticles.

    PubMed

    Su, Fenghua; Lv, Xiaoming; Miao, Menghe

    2015-02-18

    Yarn supercapacitors are promising power sources for flexible electronic applications that require conventional fabric-like durability and wearer comfort. Carbon nanotube (CNT) yarn is an attractive choice for constructing yarn supercapacitors used in wearable textiles because of its high strength and flexibility. However, low capacitance and energy density limits the use of pure CNT yarn in wearable high-energy density devices. Here, transitional metal oxide pseudocapacitive materials NiO and Co3 O4 are deposited on as-spun CNT yarn surface using a simple electrodeposition process. The Co3 O4 deposited on the CNT yarn surface forms a uniform hybridized CNT@Co3 O4 layer. The two-ply supercapacitors formed from the CNT@Co3 O4 composite yarns display excellent electrochemical properties with very high capacitance of 52.6 mF cm(-2) and energy density of 1.10 μWh cm(-2) . The high performance two-ply CNT@Co3 O4 yarn supercapacitors are mechanically and electrochemically robust to meet the high performance requirements of power sources for wearable electronics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Modified Pull-out Suture in Posterior Root Tear of the Medial Meniscus: Using a Posteromedial Portal.

    PubMed

    Cho, Jin Ho

    2012-06-01

    In cases with root tear of the medial meniscus posterior horn, the meniscus usually can be repaired by a pull out suture technique. However, there is difficulty in manipulating a suture hook via the anteromedial portal and looking through the arthroscopic camera via anterolateral portal in the narrow medial joint space at the same time. This article describes a modified simple pull out suture technique for root tear of the medial meniscus posterior horn using a posteromedial portal that provides a safe and easy handling of the suture hook. Our indications of this technique used in patients with Outerbridge 1-2 arthritic change and minimal varus axis change. Benefits of this technique are simple, less invasive, and reduced operation time by simultaneous suture with a hook via posteromedial portal and pulling of a string with grasper. It may reduce the possibility of an additional chondral or meniscal injury.

  17. Forced reptation revealed by chain pull-out simulations.

    PubMed

    Bulacu, Monica; van der Giessen, Erik

    2009-08-14

    We report computation results obtained from extensive molecular dynamics simulations of tensile disentanglement of connector chains placed at the interface between two polymer bulks. Each polymer chain (either belonging to the bulks or being a connector) is treated as a sequence of beads interconnected by springs, using a coarse-grained representation based on the Kremer-Grest model, extended to account for stiffness along the chain backbone. Forced reptation of the connectors was observed during their disentanglement from the bulk chains. The extracted chains are clearly seen following an imaginary "tube" inside the bulks as they are pulled out. The entropic and energetic responses to the external deformation are investigated by monitoring the connector conformation tensor and the modifications of the internal parameters (bonds, bending, and torsion angles along the connectors). The work needed to separate the two bulks is computed from the tensile force induced during debonding in the connector chains. The value of the work reached at total separation is considered as the debonding energy G. The most important parameters controlling G are the length (n) of the chains placed at the interface and their areal density. Our in silico experiments are performed at relatively low areal density and are disregarded if chain scission occurs during disentanglement. As predicted by the reptation theory, for this pure pull-out regime, the power exponent from the scaling G proportional, variant n(a) is a approximately 2, irrespective of chain stiffness. Small variations are found when the connectors form different number of stitches at the interface, or when their length is randomly distributed in between the two bulks. Our results show that the effects of the number of stitches and of the randomness of the block lengths have to be considered together, especially when comparing with experiments where they cannot be controlled rigorously. These results may be significant for

  18. Improvement of system capacitance via weavable superelastic biscrolled yarn supercapacitors

    NASA Astrophysics Data System (ADS)

    Choi, Changsoon; Kim, Kang Min; Kim, Keon Jung; Lepró, Xavier; Spinks, Geoffrey M.; Baughman, Ray H.; Kim, Seon Jeong

    2016-12-01

    Yarn-based supercapacitors having improved performance are needed for existing and emerging wearable applications. Here, we report weavable carbon nanotube yarn supercapacitors having high performance because of high loadings of rapidly accessible charge storage particles (above 90 wt% MnO2). The yarn electrodes are made by a biscrolling process that traps host MnO2 nanoparticles within the galleries of helically scrolled carbon nanotube sheets, which provide strength and electrical conductivity. Despite the high loading of brittle metal oxide particles, the biscrolled solid-state yarn supercapacitors are flexible and can be made elastically stretchable (up to 30% strain) by over-twisting to produce yarn coiling. The maximum areal capacitance of the yarn electrodes were up to 100 times higher than for previously reported fibres or yarn supercapacitors. Similarly, the energy density of complete, solid-state supercapacitors made from biscrolled yarn electrodes with gel electrolyte coating were significantly higher than for previously reported fibre or yarn supercapacitors.

  19. Improvement of system capacitance via weavable superelastic biscrolled yarn supercapacitors

    PubMed Central

    Choi, Changsoon; Kim, Kang Min; Kim, Keon Jung; Lepró, Xavier; Spinks, Geoffrey M.; Baughman, Ray H.; Kim, Seon Jeong

    2016-01-01

    Yarn-based supercapacitors having improved performance are needed for existing and emerging wearable applications. Here, we report weavable carbon nanotube yarn supercapacitors having high performance because of high loadings of rapidly accessible charge storage particles (above 90 wt% MnO2). The yarn electrodes are made by a biscrolling process that traps host MnO2 nanoparticles within the galleries of helically scrolled carbon nanotube sheets, which provide strength and electrical conductivity. Despite the high loading of brittle metal oxide particles, the biscrolled solid-state yarn supercapacitors are flexible and can be made elastically stretchable (up to 30% strain) by over-twisting to produce yarn coiling. The maximum areal capacitance of the yarn electrodes were up to 100 times higher than for previously reported fibres or yarn supercapacitors. Similarly, the energy density of complete, solid-state supercapacitors made from biscrolled yarn electrodes with gel electrolyte coating were significantly higher than for previously reported fibre or yarn supercapacitors. PMID:27976668

  20. Improvement of system capacitance via weavable superelastic biscrolled yarn supercapacitors.

    PubMed

    Choi, Changsoon; Kim, Kang Min; Kim, Keon Jung; Lepró, Xavier; Spinks, Geoffrey M; Baughman, Ray H; Kim, Seon Jeong

    2016-12-15

    Yarn-based supercapacitors having improved performance are needed for existing and emerging wearable applications. Here, we report weavable carbon nanotube yarn supercapacitors having high performance because of high loadings of rapidly accessible charge storage particles (above 90 wt% MnO 2 ). The yarn electrodes are made by a biscrolling process that traps host MnO 2 nanoparticles within the galleries of helically scrolled carbon nanotube sheets, which provide strength and electrical conductivity. Despite the high loading of brittle metal oxide particles, the biscrolled solid-state yarn supercapacitors are flexible and can be made elastically stretchable (up to 30% strain) by over-twisting to produce yarn coiling. The maximum areal capacitance of the yarn electrodes were up to 100 times higher than for previously reported fibres or yarn supercapacitors. Similarly, the energy density of complete, solid-state supercapacitors made from biscrolled yarn electrodes with gel electrolyte coating were significantly higher than for previously reported fibre or yarn supercapacitors.

  1. Trichotillomania (Hair-Pulling Disorder)

    MedlinePlus

    Trichotillomania (hair-pulling disorder) Overview Trichotillomania (trik-o-til-o-MAY-nee-uh), also called hair-pulling disorder, is a mental disorder that involves recurrent, irresistible urges to pull out hair from your scalp, eyebrows or other areas of ...

  2. Acoustic methods to monitor sliver linear density and yarn strength

    DOEpatents

    Sheen, Shuh-Haw; Chien, Hual-Te; Raptis, Apostolos C.

    1997-01-01

    Methods and apparatus are provided for monitoring sliver and yarn characteristics. Transverse waves are generated relative to the sliver or yarn. At least one acoustic sensor is in contact with the sliver or yarn for detecting waves coupled to the sliver or yarn and for generating a signal. The generated signal is processed to identify the predefined characteristics including sliver or yarn linear density. The transverse waves can be generated with a high-powered acoustic transmitter spaced relative to the sliver or yarn with large amplitude pulses having a central frequency in a range between 20 KHz and 40 KHz applied to the transmitter. The transverse waves can be generated by mechanically agitating the sliver or yarn with a tapping member.

  3. Correlation of pull-out strength of cement-augmented pedicle screws with CT-volumetric measurement of cement.

    PubMed

    Fölsch, Christian; Goost, Hans; Figiel, Jens; Paletta, Jürgen R J; Schultz, Wolfgang; Lakemeier, Stefan

    2012-12-01

    Cement augmentation of pedicle screws increases fixation strength in an osteoporotic spine. This study was designed to determine the cement distribution and the correlation between the pull-out strength of the augmented screw and the cement volume within polyurethane (PU) foam. Twenty-eight cannulated pedicle screws (6×45 mm) (Peter Brehm, Erlangen, Germany) with four holes at the distal end of the screw were augmented with the acrylic Stabilit ER Bone Cement Vertebral Augmentation System (DFine Inc., San Jose, CA, USA) and implanted into open-cell rigid PU foam (Pacific Research Laboratories, Vashon Island, WA, USA) with a density of 0.12 g/cm3, resembling severe osteoporosis. Volumetric measurement of the cement with consideration of the distribution around the screws was done with multislice computed tomography scan (Somatom Definition, Siemens, Erlangen, Germany). Pull-out strength was tested with a servohydraulic system (MTS System Corporation, Eden Prairie, MN, USA), and nonaugmented screws served as control. Pearson's correlation coefficient with significance level α=0.05 and one-way analysis of variance test were used. We found a high (r=0.88) and significant (p<0.01) correlation between the cement volume and the pull-out strength, which increased by more than 5-fold with a volume of 3 ml. The correlation appeared linear at least up to 4 ml cement volume and failure always occurred at the cement-bone interface. The cement distribution was symmetric and circular around the most proximal hole, with a distance of 14 mm from the tip, and nearly 90% of the cement was found 6 mm distal and cranial to it. The 95% confidence interval for the relative amount of cement was 37%-41% within 2 mm of the most proximal hole. Compared with the control, a cement volume between 2.0 and 3.0 ml increased the pull-out strength significantly and is relevant for clinical purposes, whereas a volume of 0.5 ml did not. A cement volume beyond 3.0 ml should further increase the pull-out

  4. Magnetic-Assisted, Self-Healable, Yarn-Based Supercapacitor.

    PubMed

    Huang, Yang; Huang, Yan; Zhu, Minshen; Meng, Wenjun; Pei, Zengxia; Liu, Chang; Hu, Hong; Zhi, Chunyi

    2015-06-23

    Yarn-based supercapacitors have received considerable attention recently, offering unprecedented opportunities for future wearable electronic devices (e.g., smart clothes). However, the reliability and lifespan of yarn-based supercapacitors can be seriously limited by accidental mechanical damage during practical applications. Therefore, a supercapacitor endowed with mechanically and electrically self-healing properties is a brilliant solution to the challenge. Compared with the conventional planar-like or large wire-like structure, the reconnection of the broken yarn electrode composed of multiple tiny fibers (diameter <20 μm) is much more difficult and challenging, which directly affects the restoration of electrical conductivity after damage. Herein, a self-healable yarn-based supercapacitor that ensures the reconnection of broken electrodes has been successfully developed by wrapping magnetic electrodes around a self-healing polymer shell. The strong force from magnetic attraction between the broken yarn electrodes benefits reconnection of fibers in the yarn electrodes during self-healing and thus offers an effective strategy for the restoration of electric conductivity, whereas the polymer shell recovers the configuration integrity and mechanical strength. With the design, the specific capacitance of our prototype can be restored up to 71.8% even after four breaking/healing cycles with great maintenance of the whole device's mechanical properties. This work may inspire the design and fabrication of other distinctive self-healable and wearable electronic devices.

  5. Quantitative in-situ scanning electron microscope pull-out experiments and molecular dynamics simulations of carbon nanotubes embedded in palladium

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

    Hartmann, S., E-mail: steffen.hartmann@etit.tu-chemnitz.de; Blaudeck, T.; Hermann, S.

    2014-04-14

    In this paper, we present our results of experimental and numerical pull-out tests on carbon nanotubes (CNTs) embedded in palladium. We prepared simple specimens by employing standard silicon wafers, physical vapor deposition of palladium and deposition of CNTs with a simple drop coating technique. An AFM cantilever with known stiffness connected to a nanomanipulation system was utilized inside a scanning electron microscope (SEM) as a force sensor to determine forces acting on a CNT during the pull-out process. SEM-images of the cantilever attached to a CNT have been evaluated for subsequent displacement steps with greyscale correlation to determine the cantilevermore » deflection. We compare the experimentally obtained pull-out forces with values of numerical investigations by means of molecular dynamics and give interpretations for deviations according to material impurities or defects and their influence on the pull-out data. We find a very good agreement of force data from simulation and experiment, which is 17 nN and in the range of 10–61 nN, respectively. Our findings contribute to the ongoing research of the mechanical characterization of CNT-metal interfaces. This is of significant interest for the design of future mechanical sensors utilizing the intrinsic piezoresistive effect of CNTs or other future devices incorporating CNT-metal interfaces.« less

  6. Thermal-electrical properties and resistance stability of silver coated yarns

    NASA Astrophysics Data System (ADS)

    Li, Yafang; Liu, Hao; Li, Xiaojiu

    2017-03-01

    Thermal-electrical properties and resistance stability of silver yarns was researched to evaluate the performance be a heating element. Three samples of silver coated yarns with different linear density and electrical resistivity, which obtained by market. Silver coated yarns were placed at the high temperature condition for ageing. The electrical resistances of yarns were increased with the ageing process. The infrared photography instrument was used to measurement the temperature variation of silver coated yarns by applied different current on. The result shows that the temperature rise with the power increases.

  7. Preparation of Highly Conductive Yarns by an Optimized Impregnation Process

    NASA Astrophysics Data System (ADS)

    Amba Sankar, K. N.; Mohanta, Kallol

    2017-12-01

    We report the development of the electrical conductivity in textile yarns through impregnation and post-treatment of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The conductive polymer is deposited on fibers, which fills the gap space within the hierarchical structure of the yarns. Organic nonpolar solvents act as reducing agent to increase the density of PEDOT moieties on the yarns, galvanizing increment in conductivity values. Post-treatment by ethylene glycol transforms the resonance configuration of the conductive moieties of conjugated polymer, which helps in further enhancement of electrical conductivity of the yarns. We have optimized the method in terms of loading and conformal change of the polymer to have a lesser resistance of the coated conductive yarns. The minimum resistance achieved has a value of 77 Ωcm-1. This technique of developing conductivity in conventional yarns enables retaining the flexibility of yarns and feeling of softness which would find suitable applications for wearable electronics.

  8. Towards Multifunctional Characteristics of Embedded Structures With Carbon Nanotube Yarns

    NASA Technical Reports Server (NTRS)

    Hernandez, Corey D.; Gates, Thomas S.; Kahng, Seun K.

    2006-01-01

    This paper presents recent results on research of achieving multifunctional structures utilizing Carbon Nanotube (CNT) yarns. The investigation centers on creating composite structures with CNT yarns to simultaneously achieve increases in mechanical strength and the ability to sense strain. The CNT yarns used in our experiments are of the single-ply and two-ply variety with the single-ply yarns having diameters on the order of 10-20 m. The yarns are embedded in silicon rubber and polyurethane test specimens. Mechanical tests show an increase in modulus of elasticity, with an additional weight increase of far less than one-percent. Sensing characteristics of the yarns are investigated on stainless steel test beams in an electrical bridge configuration, and are observed to have a strain sensitivity of 0.7mV/V/1000 micro-strain. Also reported are measurements of the average strain distribution along the direction of the CNT yarns on square silicon rubber membranes.

  9. Preparation of Highly Conductive Yarns by an Optimized Impregnation Process

    NASA Astrophysics Data System (ADS)

    Amba Sankar, K. N.; Mohanta, Kallol

    2018-03-01

    We report the development of the electrical conductivity in textile yarns through impregnation and post-treatment of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The conductive polymer is deposited on fibers, which fills the gap space within the hierarchical structure of the yarns. Organic nonpolar solvents act as reducing agent to increase the density of PEDOT moieties on the yarns, galvanizing increment in conductivity values. Post-treatment by ethylene glycol transforms the resonance configuration of the conductive moieties of conjugated polymer, which helps in further enhancement of electrical conductivity of the yarns. We have optimized the method in terms of loading and conformal change of the polymer to have a lesser resistance of the coated conductive yarns. The minimum resistance achieved has a value of 77 Ωcm-1. This technique of developing conductivity in conventional yarns enables retaining the flexibility of yarns and feeling of softness which would find suitable␣applications for wearable electronics.

  10. Three-dimensional measurement of yarn hairiness via multiperspective images

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Xu, Bugao; Gao, Weidong

    2018-02-01

    Yarn hairiness is one of the essential parameters for assessing yarn quality. Most of the currently used yarn measurement systems are based on two-dimensional (2-D) photoelectric measurements, which are likely to underestimate levels of yarn hairiness because hairy fibers on a yarn surface are often projected or occluded in these 2-D systems. A three-dimensional (3-D) test method for hairiness measurement using a multiperspective imaging system is presented. The system was developed to reconstruct a 3-D yarn model for tracing the actual length of hairy fibers on a yarn surface. Five views of a yarn from different perspectives were created by two angled mirrors and simultaneously captured in one panoramic picture by a camera. A 3-D model was built by extracting the yarn silhouettes in the five views and transferring the silhouettes into a common coordinate system. From the 3-D model, curved hair fibers were traced spatially so that projection and occlusion occurring in the current systems could be avoided. In the experiment, the proposed method was compared with two commercial instruments, i.e., the Uster Tester and Zweigle Tester. It is demonstrated that the length distribution of hairy fibers measured from the 3-D model showed an exponential growth when the fiber length is sorted from shortest to longest. The hairiness measurements, such as H-value, measured by the multiperspective method were highly consistent with those of Uster Tester (r=0.992) but had larger values than those obtained from Uster Tester and Zweigle Tester, proving that the proposed method corrected underestimated hairiness measurements in the commercial systems.

  11. Pull-Out Strength and Bond Behavior of Prestressing Strands in Prestressed Self-Consolidating Concrete

    PubMed Central

    Long, Wu-Jian; Khayat, Kamal Henri; Lemieux, Guillaume; Hwang, Soo-Duck; Xing, Feng

    2014-01-01

    With the extensive use of self-consolidating concrete (SCC) worldwide, it is important to ensure that such concrete can secure uniform in-situ mechanical properties that are similar to those obtained with properly consolidated concrete of conventional fluidity. Ensuring proper stability of SCC is essential to enhance the uniformity of in-situ mechanical properties, including bond to embedded reinforcement, which is critical for structural engineers considering the specification of SCC for prestressed applications. In this investigation, Six wall elements measuring 1540 mm × 2150 mm × 200 mm were cast using five SCC mixtures and one reference high-performance concrete (HPC) of normal consistency to evaluate the uniformity of bond strength between prestressing strands and concrete as well as the distribution of compressive strength obtained from cores along wall elements. The evaluated SCC mixtures used for casting wall elements were proportioned to achieve a slump flow consistency of 680 ± 15 mm and minimum caisson filling capacity of 80%, and visual stability index of 0.5 to 1. Given the spreads in viscosity and static stability of the SCC mixtures, the five wall elements exhibited different levels of homogeneity in in-situ compressive strength and pull-out bond strength. Test results also indicate that despite the high fluidity of SCC, stable concrete can lead to more homogenous in-situ properties than HPC of normal consistency subjected to mechanical vibration. PMID:28788223

  12. Pull-Out Strength and Bond Behavior of Prestressing Strands in Prestressed Self-Consolidating Concrete.

    PubMed

    Long, Wu-Jian; Khayat, Kamal Henri; Lemieux, Guillaume; Hwang, Soo-Duck; Xing, Feng

    2014-10-10

    With the extensive use of self-consolidating concrete (SCC) worldwide, it is important to ensure that such concrete can secure uniform in-situ mechanical properties that are similar to those obtained with properly consolidated concrete of conventional fluidity. Ensuring proper stability of SCC is essential to enhance the uniformity of in-situ mechanical properties, including bond to embedded reinforcement, which is critical for structural engineers considering the specification of SCC for prestressed applications. In this investigation, Six wall elements measuring 1540 mm × 2150 mm × 200 mm were cast using five SCC mixtures and one reference high-performance concrete (HPC) of normal consistency to evaluate the uniformity of bond strength between prestressing strands and concrete as well as the distribution of compressive strength obtained from cores along wall elements. The evaluated SCC mixtures used for casting wall elements were proportioned to achieve a slump flow consistency of 680 ± 15 mm and minimum caisson filling capacity of 80%, and visual stability index of 0.5 to 1. Given the spreads in viscosity and static stability of the SCC mixtures, the five wall elements exhibited different levels of homogeneity in in-situ compressive strength and pull-out bond strength. Test results also indicate that despite the high fluidity of SCC, stable concrete can lead to more homogenous in-situ properties than HPC of normal consistency subjected to mechanical vibration.

  13. Strain and Temperature Sensing Properties of Multiwalled Carbon Nanotube Yarn Composites

    NASA Technical Reports Server (NTRS)

    Kahng, Seun K.; Gates, Thomas S.; Jefferson, Gail D.

    2008-01-01

    Strain and temperature response of Multiwalled Carbon Nanotube (MWCNT/CNT) yarns on a stainless steel test beam has been studied. The carbon nanotube yarns are spun from a multiwalled carbon nanotube forest grown on a silicon substrate to a 4-ply yarn with a diameter of about 15-20 microns. Four of the 4-ply CNT yarns are arranged in a Wheatstone bridge configuration on the stainless steel test beam using a thin layer of polyurethane resin that insulates and protects the yarns from the test beam. Strain sensitivities of the CNT yarn sensors range from 1.39 to 1.75 mV/V/1000 microstrain at room temperature, and temperature sensitivity of the CNT yarn bridge is 91 microA/degC. Resistance of the yarns range from 215 to 270 ohms for CNT yarn length of approximately 5 mm. Processes used in attaching the CNT yarns on the test beam and experimental procedures used for the measurements are described. Conventional metallic foil strain gages are attached to the test beam to compare with the CNT sensors. The study demonstrates multifunctional capability of the sensor for strain and temperature measurements and shows its applicability where engineering strain is less than 3%.

  14. Comparison of Transverse Intraosseous Loop Technique and Pull Out Suture for Reinsertion of the Flexor Digitorum Profundus tendon. A Retrospective Study.

    PubMed

    Rigó, István Zoltán; Røkkum, Magne

    2013-12-01

    We compared the results of two methods for reinsertion of flexor digitorum profundus tendons retrospectively. In 35 fingers of 29 patients pull-out suture and in 13 fingers of 11 patients transverse intraosseous loop technique was performed with a mean follow-up of 8 and 6 months, respectively. Eleven and nine fingers achieved "excellent" or "good" function according to Strickland and Glogovac at 8 weeks; 20 and ten at the last control in the pull-out and transverse intraosseous loop groups, respectively. The difference at 8 weeks was statistically significant in favour of the transverse intraosseous loop group. Ten patients underwent 12 complications in the pull-out group (four superficial infections; one rerupture, one PIP and one DIP joint contracture, one adhesion, two granulomas, one nail deformity and one carpal tunnel syndrome) and four of them were reoperated (one carpal tunnel release, one teno-arthrolysis and two resections of granuloma). There was no complication and no reoperation in the transverse intraosseous loop group, the difference being statistically significant for the former. In our study the transverse intraosseous loop technique seemed to be a safe alternative with possibly better functional results compared to the pull-out suture.

  15. Design and Fabrication of Smart Diapers with Antibacterial Yarn

    PubMed Central

    Lin, Jia-Horng; Shiu, Bing-Chiuan; Lou, Ching-Wen

    2017-01-01

    In this study, intelligent eco-diapers are made by combining antibacterial yarns coated with quaternary ammonium salts with conductive yarns to improve caretaking for urinary incontinence. The combination of conductive yarns and sensors can detect the moisture content in eco-diapers, and an alarm is sent when moisture is significant. A wireless module is used to send detected signals to a smartphone or tablet PC via the Internet. This concept is used for a scenario in which nurses do not randomly check on patients in a long-term care institution. When used offline, eco-diapers can send caregivers an alarm for the need to change diapers via cell phones. The diameters of the copper and silver-plated copper fibers are 0.08 and 0.10 mm, respectively. Cotton yarns are twisted with copper and silver-plated copper fibers to form the conductive yarns, which are 0.12 mm in diameter. Moreover, 30-count cotton and 150 D nylon yarns are coated with quaternary ammonium salt via dyeing and finishing processes to form antibacterial yarns. In the current study, intelligent eco-diapers are tested for their electrical and antibacterial properties as specified by AATC and JISL test standards. PMID:29065646

  16. Influence of different adhesive systems on the pull-out bond strength of glass fiber posts.

    PubMed

    da Silva, Luciana Mendonça; Andrade, Andréa Mello de; Machuca, Melissa Fernanda Garcia; da Silva, Paulo Maurício Batista; da Silva, Ricardo Virgolino C; Veronezi, Maria Cecília

    2008-01-01

    This in vitro study evaluated the tensile bond strength of glass fiber posts (Reforpost - Angelus-Brazil) cemented to root dentin with a resin cement (RelyX ARC - 3M/ESPE) associated with two different adhesive systems (Adper Single Bond - 3M/ESPE and Adper Scotchbond Multi Purpose (MP) Plus - 3M/ESPE), using the pull-out test. Twenty single-rooted human teeth with standardized root canals were randomly assigned to 2 groups (n=10): G1- etching with 37% phosphoric acid gel (3M/ESPE) + Adper Single Bond + #1 post (Reforpost - Angelus) + four #1 accessory posts (Reforpin - Angelus) + resin cement; G2- etching with 37% phosphoric acid gel + Adper Scotchbond MP Plus + #1 post + four #1 accessory posts + resin cement. The specimens were stored in distilled water at 37 degrees C for 7 days and submitted to the pull-out test in a universal testing machine (EMIC) at a crosshead speed of 0.5 mm/min. The mean values of bond strength (kgf) and standard deviation were: G1- 29.163 +/- 7.123; G2- 37.752 +/-13.054. Statistical analysis (Student's t-test; a=0.05 showed no statistically significant difference (p<0.05) between the groups. Adhesive bonding failures between resin cement and root canal dentin surface were observed in both groups, with non-polymerized resin cement in the apical portion of the post space when Single Bond was used (G1). The type of adhesive system employed on the fiber post cementation did not influence the pull-out bond strength.

  17. Pull Out Negativity by Its Roots.

    ERIC Educational Resources Information Center

    DuFour, Rick; Burnette, Becky

    2002-01-01

    Principals are well-positioned to cultivate their schools' cultures. They must remain vigilant in rooting out the beginnings of negative culture, including such teacher attitudes and behaviors as not feeling responsible for student learning, preferring to work alone, wanting to protect their territory, and focusing on activity rather than results.…

  18. Scratch-resistant, highly conductive, and high-strength carbon nanotube-based composite yarns.

    PubMed

    Liu, Kai; Sun, Yinghui; Lin, Xiaoyang; Zhou, Ruifeng; Wang, Jiaping; Fan, Shoushan; Jiang, Kaili

    2010-10-26

    High-strength and conductive carbon nanotube (CNT) yarns are very attractive in many potential applications. However, there is a difficulty when simultaneously enhancing the strength and conductivity of CNT yarns. Adding some polymers into CNT yarns to enhance their strength will decrease their conductivity, while treating them in acid or coating them with metal nanoparticles to enhance their conductivity will reduce their strength. To overcome this difficulty, here we report a method to make high-strength and highly conductive CNT-based composite yarns by using a continuous superaligned CNT (SACNT) yarn as a conductive framework and then inserting polyvinyl alcohol (PVA) into the intertube spaces of the framework through PVA/dimethyl sulphoxide solution to enhance the strength of yarns. The as-produced CNT/PVA composite yarns possess very high tensile strengths up to 2.0 GPa and Young's moduli more than 120 GPa, much higher than those of the CNT/PVA yarns reported. The electric conductivity of as-produced composite yarns is as high as 9.2 × 10(4) S/m, comparable to HNO(3)-treated or Au nanoparticle-coated CNT yarns. These composite yarns are flexible, lightweight, scratch-resistant, very stable in the lab environment, and resistant to extremely humid ambient and as a result can be woven into high-strength and heatable fabrics, showing potential applications in flexible heaters, bullet-proof vests, radiation protection suits, and spacesuits.

  19. Method and apparatus for sizing and separating warp yarns using acoustical energy

    DOEpatents

    Sheen, Shuh-Haw; Chien, Hual-Te; Raptis, Apostolos C.; Kupperman, David S.

    1998-01-01

    A slashing process for preparing warp yarns for weaving operations including the steps of sizing and/or desizing the yarns in an acoustic resonance box and separating the yarns with a leasing apparatus comprised of a set of acoustically agitated lease rods. The sizing step includes immersing the yarns in a size solution contained in an acoustic resonance box. Acoustic transducers are positioned against the exterior of the box for generating an acoustic pressure field within the size solution. Ultrasonic waves that result from the acoustic pressure field continuously agitate the size solution to effect greater mixing and more uniform application and penetration of the size onto the yarns. The sized yarns are then separated by passing the warp yarns over and under lease rods. Electroacoustic transducers generate acoustic waves along the longitudinal axis of the lease rods, creating a shearing motion on the surface of the rods for splitting the yarns.

  20. Method and apparatus for sizing and separating warp yarns using acoustical energy

    DOEpatents

    Sheen, S.H.; Chien, H.T.; Raptis, A.C.; Kupperman, D.S.

    1998-05-19

    A slashing process is disclosed for preparing warp yarns for weaving operations including the steps of sizing and/or desizing the yarns in an acoustic resonance box and separating the yarns with a leasing apparatus comprised of a set of acoustically agitated lease rods. The sizing step includes immersing the yarns in a size solution contained in an acoustic resonance box. Acoustic transducers are positioned against the exterior of the box for generating an acoustic pressure field within the size solution. Ultrasonic waves that result from the acoustic pressure field continuously agitate the size solution to effect greater mixing and more uniform application and penetration of the size onto the yarns. The sized yarns are then separated by passing the warp yarns over and under lease rods. Electroacoustic transducers generate acoustic waves along the longitudinal axis of the lease rods, creating a shearing motion on the surface of the rods for splitting the yarns. 2 figs.

  1. Antifungal activity of fabrics knitted by metalized Silver/Polyester composite yarn

    NASA Astrophysics Data System (ADS)

    Özkan, İ.; Duru Baykal, P.

    2017-10-01

    In this study, antifungal properties of fabric knitted from metalized silver/polyester composite yarn were investigated. Intermingling is an alternative technique for yarn blending process. Yarns having different features can be combined by feeding the same intermingling jet. This process is defined as commingling. In the study, intermingling process was used to produce metalized silver/polyester composite yarn. Commingled yarns were knitted to single jersey fabrics by IPM brand sample type circular knitting machine. Antifungal activity test was applied to samples against Aspergillus Niger according to AATCC 30 test procedure. It has been identified that the application provides antifungal activity to fabric.

  2. Crimp-Imbalanced Protective (CRIMP) Fabrics: An Analytical Investigation into the Relationship Between Crimp Contents, Energy Absorption, and Fabric Ballistic Performance

    DTIC Science & Technology

    2010-09-15

    migration and yarn stretching. These mechanisms relate to the force required to pull a yarn out from the fabric. If the fabric is made of low...the following assumptions were made : The fabric architecture is plain-woven. The yarns have a circular cross section with diameter D equal to 1.0... Bulletproof Aramid Fabric," Journal of Materials Science, vol. 32, pp. 4167-4173, 1997. 16. D. A. Shockey, D. C. Erlich, and J. W. Simons, "Improved

  3. An all-solid-state yarn supercapacitor using cotton yarn electrodes coated with polypyrrole nanotubes.

    PubMed

    Wei, Chengzhuo; Xu, Qi; Chen, Zeqi; Rao, Weida; Fan, Lingling; Yuan, Ye; Bai, Zikui; Xu, Jie

    2017-08-01

    A novel all-solid-state yarn supercapacitor (YSC) has been fabricated by using the cotton yarns coated with polypyrrole (PPy) nanotubes. The interconnected network structure of PPy can increase the surface area as well as the electrode/electrolyte interface area, thus resulting in improved electrochemical performance. For the proposed YSC, a high areal-specific capacitance of 74.0mFcm -2 and a desirable energy density of 7.5μWhcm -2 are achieved. The flexibility of the YSC demonstrates that it is suitable for the integration as flexible power sources in wearable electronic textiles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Asymmetric carbon nanotube-MnO₂ two-ply yarn supercapacitors for wearable electronics.

    PubMed

    Su, Fenghua; Miao, Menghe

    2014-04-04

    Strong and flexible two-ply carbon nanotube yarn supercapacitors are electrical double layer capacitors that possess relatively low energy storage capacity. Pseudocapacitance metal oxides such as MnO₂ are well known for their high electrochemical performance and can be coated on carbon nanotube yarns to significantly improve the performance of two-ply carbon nanotube yarn supercapacitors. We produced a high performance asymmetric two-ply yarn supercapacitor from as-spun CNT yarn and CNT@Mn₂2 composite yarn in aqueous electrolyte. The as-spun CNT yarn serves as negative electrode and the CNT@MnO₂ composite yarn as positive electrode. This asymmetric architecture allows the operating potential window to be extended from 1.0 to 2.0 V and results in much higher energy and power densities than the reference symmetric two-ply yarn supercapacitors, reaching 42.0 Wh kg(-1) at a lower power density of 483.7 W kg(-1), and 28.02 Wh kg(-1) at a higher power density of 19,250 W kg(-1). The asymmetric supercapacitor can sustain cyclic charge-discharge and repeated folding/unfolding actions without suffering significant deterioration of specific capacitance. The combination of high strength, flexibility and electrochemical performance makes the asymmetric two-ply yarn supercapacitor a suitable power source for flexible electronic devices for applications that require high durability and wearer comfort.

  5. Physical and Thermal Comfort Properties of Viscose Fabrics made from Vortex and Ring Spun Yarns

    NASA Astrophysics Data System (ADS)

    Thilagavathi, G.; Muthukumar, N.; Kumar, V. Kiran; Sadasivam, Sanjay; Sidharth, P. Mithun; Nikhil Jain, G.

    2017-06-01

    Viscose fiber is frequently preferred for various types of inner and outer knitwear products for its comfort and visual characteristics. In this study, the physical and thermal comfort properties of viscose fabrics made from ring and vortex yarns have been studied to explore the impact of spinning process on fabric properties. 100% viscose fibers were spun into yarns by ring and vortex spinning and the developed yarns were converted to single jersey fabrics. The results indicated that fabrics made from vortex spun yarns had better pilling resistance over that of those from ring spun yarns. There was no significant difference between bursting strength values of vortex and ring spun yarn fabrics. Fabrics made from ring yarn had better dimensional stability compared to fabrics made from vortex yarn. The air permeability and water vapour permeability of vortex yarn fabrics were higher than ring spun yarn fabrics. The vortex yarn fabrics had better thermal comfort properties compared to ring yarn fabrics.

  6. Thread-like supercapacitors based on one-step spun nanocomposite yarns.

    PubMed

    Meng, Qinghai; Wang, Kai; Guo, Wei; Fang, Jin; Wei, Zhixiang; She, Xilin

    2014-08-13

    Thread-like electronic devices have attracted great interest because of their potential applications in wearable electronics. To produce high-performance, thread-like supercapacitors, a mixture of stable dispersions of single-walled carbon nanotubes and conducting polyaniline nanowires are prepared. Then, the mixture is spun into flexible yarns with a polyvinyl alcohol outer sheath by a one-step spinning process. The composite yarns show excellent mechanical properties and high electrical conductivities after sufficient washing to remove surfactants. After applying a further coating layer of gel electrolyte, two flexible yarns are twisted together to form a thread-like supercapacitor. The supercapacitor based on these two yarns (SWCNTs and PAniNWs) possesses a much higher specific capacitance than that based only on pure SWCNTs yarns, making it an ideal energy-storage device for wearable electronics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Potentiometric sensors using cotton yarns, carbon nanotubes and polymeric membranes.

    PubMed

    Guinovart, Tomàs; Parrilla, Marc; Crespo, Gastón A; Rius, F Xavier; Andrade, Francisco J

    2013-09-21

    A simple and generalized approach to build electrochemical sensors for wearable devices is presented. Commercial cotton yarns are first turned into electrical conductors through a simple dyeing process using a carbon nanotube ink. These conductive yarns are then partially coated with a suitable polymeric membrane to build ion-selective electrodes. Potentiometric measurements using these yarn-potentiometric sensors are demonstrated. Examples of yarns that can sense pH, K(+) and NH4(+) are presented. In all cases, these sensing yarns show limits of detection and linear ranges that are similar to those obtained with lab-made solid-state ion-selective electrodes. Through the immobilization of these sensors in a band-aid, it is shown that this approach could be easily implemented in a wearable device. Factors affecting the performance of the sensors and future potential applications are discussed.

  8. Multifunctional Yarns and Fabrics for Energy Applications (NBIT Phase 2)

    DTIC Science & Technology

    2013-05-29

    project focus on developing biscrolled carbon nanotube yarns and textiles for supercapacitor /battery and fuel cell electrode applications was chosen...redox supercapacitors resulted from program work. While project focus was on fuel cell and energy storage electrodes based on biscrolled yarns...project focus on developing biscrolled carbon nanotube yarns and textiles for supercapacitor /battery and fuel cell electrode applications was chosen

  9. Development of yarn breakage detection software system based on machine vision

    NASA Astrophysics Data System (ADS)

    Wang, Wenyuan; Zhou, Ping; Lin, Xiangyu

    2017-10-01

    For questions spinning mills and yarn breakage cannot be detected in a timely manner, and save the cost of textile enterprises. This paper presents a software system based on computer vision for real-time detection of yarn breakage. The system and Windows8.1 system Tablet PC, cloud server to complete the yarn breakage detection and management. Running on the Tablet PC software system is designed to collect yarn and location information for analysis and processing. And will be processed after the information through the Wi-Fi and http protocol sent to the cloud server to store in the Microsoft SQL2008 database. In order to follow up on the yarn break information query and management. Finally sent to the local display on time display, and remind the operator to deal with broken yarn. The experimental results show that the system of missed test rate not more than 5%o, and no error detection.

  10. On the pull-out of fibers with fractal-tree structure and the interference of strength and fracture toughness of composites

    NASA Astrophysics Data System (ADS)

    Fe, Shaoyun; Zhou, Benlian; Lung, Chiwei

    1992-06-01

    An approximate theory of pull-out of fiber with fractal-tree structure from a matrix is developed with the aim of quantifying the effects of the fractal-tree structure of the fiber. In the experimental investigation of the pull-out of the synthetic fiber with fractal-tree structure, it was generally observed that the force and energy of fiber pullout increase with the branching angle. The application of this theory to experiment is successful. The strength and fracture toughness of composites reinforced by this kind of fiber are inferred to be greater than those of composites reinforced by plane fibers.

  11. The arrangement of the fibers in the yarn and effect on its strength

    NASA Astrophysics Data System (ADS)

    Bobajonov, H. T.; Yuldashev, J. K.; Gafurov, J. K.; Gofurov, K.

    2017-10-01

    This article presents the results of research on the deformation changes in the initial moments of loading and unloading of conversional ring and compact yarns samples with a special strain gauge device. It was revealed that compact yarn in the initial load moment is deformed slowly doubled (4 seconds) compared to the conversional ring yarn. At the moment of unloading, on the contrary, the deformation of the compact yarn occurs rapidly (2 seconds), and the compact yarn in which a fiber foredeck regularly deformed quickly (1 second). A comparative study of resistance to stretching of the conversional ring and compact yarn based on Kelvin model was done. As a result, it has been found that the instant and long elastic module of compact yarn are slightly higher than conversional ring yarn with similar module, and the viscosity parameter which characterizes the decrease of the modulus of elasticity is lower compare with it..

  12. Lightweight electrically-powered flexible thermal laminate. [made of metal and nonconductive yarns

    NASA Technical Reports Server (NTRS)

    Dawn, F. S.; Sauers, D. G. (Inventor)

    1978-01-01

    Cross-layered woven or unwoven yarns are used to provide an active thermal control mechanism for spacecraft use. One set of yarns is composed of flexible electrically conductive metal fibers which are capable of being resistance heated by the application of voltage. Another set of yarns, nonconductive and flexible, provides mechanical strength and precludes the passage of electrical current between the metal yarns by virtue of the spacing between them. A lightweight, electrically nonconductive film is bonded to the cross-layered yarns to protect the metal yarns from the elements (minimize electrical shorts from moisture such as rain), to provide additional strength to the fabric, and to prevent conductive loss of heat in nonvacuum applications. The nonconductive film is metalized on its obverse side to provide a more uniform heat load distribution.

  13. Asymmetric carbon nanotube-MnO2 two-ply yarn supercapacitors for wearable electronics

    NASA Astrophysics Data System (ADS)

    Su, Fenghua; Miao, Menghe

    2014-04-01

    Strong and flexible two-ply carbon nanotube yarn supercapacitors are electrical double layer capacitors that possess relatively low energy storage capacity. Pseudocapacitance metal oxides such as MnO2 are well known for their high electrochemical performance and can be coated on carbon nanotube yarns to significantly improve the performance of two-ply carbon nanotube yarn supercapacitors. We produced a high performance asymmetric two-ply yarn supercapacitor from as-spun CNT yarn and CNT@MnO2 composite yarn in aqueous electrolyte. The as-spun CNT yarn serves as negative electrode and the CNT@MnO2 composite yarn as positive electrode. This asymmetric architecture allows the operating potential window to be extended from 1.0 to 2.0 V and results in much higher energy and power densities than the reference symmetric two-ply yarn supercapacitors, reaching 42.0 Wh kg-1 at a lower power density of 483.7 W kg-1, and 28.02 Wh kg-1 at a higher power density of 19 250 W kg-1. The asymmetric supercapacitor can sustain cyclic charge-discharge and repeated folding/unfolding actions without suffering significant deterioration of specific capacitance. The combination of high strength, flexibility and electrochemical performance makes the asymmetric two-ply yarn supercapacitor a suitable power source for flexible electronic devices for applications that require high durability and wearer comfort.

  14. Buckling Structured Stretchable Pseudocapacitor Yarn.

    PubMed

    Lee, Duck Weon; Lee, Jung Han; Min, Nam Ki; Jin, Joon-Hyung

    2017-09-20

    Cable-type stretchable electrochemical pseudocapacitors based on multi-walled carbon nanotube (MWCNT) sheets and two different metal oxide nanopowders (NP), i.e., MnO 2 and RuO 2 are developed using a newly-devised dry painting method to mechanically fix the NP to the elastic rubber-based MWCNT electrode substrate, resulting in a porous buckling structured pseudocapacitor yarn. Highly stretchable stylene-ethylene/butylene-stylene (SEBS) is used as the supporting elastomeric core for wrapping with the MWCNT sheets and the electroactive NP. The dry painting can successfully deposit NP on the soft SEBS surface, which is normally an unfavorable substrate for coating alien materials. The resulting yarn-type pseudocapacitor, composed of eight-layered MWCNT sheets, three-layered RuO 2 , and two-layered MnO 2 , showing a diameter of approximately 400 μm with a porous buckling structure, records a specific capacitance of 25 F g -1 . After being stretched by 200% in strain with no sacrifice of the porous buckling structure, the cable-type stretchable electrochemical pseudocapacitor yarn retains its electrical capacity, and is potentially applicable to energy storage devices for wearable electronics.

  15. Flexible helical yarn swimmers.

    PubMed

    Zakharov, A P; Leshansky, A M; Pismen, L M

    2016-09-01

    We investigate the motion of a flexible Stokesian flagellar swimmer realised as a yarn made of two intertwined elastomer fibres, one active, that can reversibly change its length in response to a local excitation causing transition to the nematic state or swelling, and the other one, a passive isotropic elastomer with identical mechanical properties. A propagating chemical wave may provide an excitation mechanism ensuring a constant length of the excited region. Generally, the swimmer moves along a helical trajectory, and the propagation and rotation velocity are very sensitive to the ratio of the excited region to the pitch of the yarn, as well as to the size of a carried load. External excitation by a moving actuating beam is less effective, unless the direction of the beam is adjusted to rotation of the swimmer.

  16. Fatigue behaviour of core-spun yarns containing filament by means of cyclic dynamic loading

    NASA Astrophysics Data System (ADS)

    Esin, S.; Osman, B.

    2017-10-01

    The behaviour of yarns under dynamic loading is important that leads to understand the growth characteristics which is exposed to repetitive loadings during usage of fabric made from these yarns. Fabric growth is undesirable property that originated from low resilience characteristics of fabric. In this study, the effects of the filament fineness and yarn linear density on fatigue behaviour of rigid-core spun yarns were determined. Cotton covered yarns containing different filament fineness of polyester (PET) draw textured yarns (DTY) (100d/36f, 100d/96f, 100d/144f, 100d/192f and 100d/333f) and yarn linear densities (37 tex, 30 tex, 25 tex and 21 tex) were manufactured by using a modified ring spinning system at the same spinning parameters. Repetitive loads were applied for 25 cycles at levels between 0.1 and 3 N. Dynamic modulus and dynamic strain of yarn samples were analyzed statistically. Results showed that filament fineness and yarn linear density have significance effect on dynamic modulus and dynamic strain after cyclic loading.

  17. Biscrolling nanotube sheets and functional guests into yarns

    NASA Astrophysics Data System (ADS)

    Baughman, Ray

    2011-03-01

    Multifunctional applications of textiles have been limited by the inability to spin important materials into yarns. Generically applicable methods are demonstrated for producing weavable yarns comprising up to 95 wt % of otherwise unspinnable particulate or nanofiber powders that remain highly functional. Scrolled 50 nm thick carbon nanotube sheets confine these powders in the galleries of irregular scroll sacks, whose observed complex structures are related to twist-dependent extension of Archimedean spirals, Fermat spirals, or spiral pairs into scrolls. The strength and electronic connectivity of a small weight fraction of scrolled carbon nanotube sheet enables yarn weaving, sewing, knotting, braiding, and charge collection. This technology is used to make yarns of superconductors, Li-ion battery materials, graphene ribbons, catalytic nanofibers for fuel cells, and Ti O2 for photocatalysis. Work done in collaboration with Shaoli Fang, Xavier Lepro-Chavez, Chihye Lewis, Raquel Ovalle-Robles, Javier Carratero-Gonzalez, Elisabet Castillo-Martinez, Mikhail Kozlov, Jiyoung Oh, Neema Rawat, Carter Haines, Mohammed Haque, Vaishnavi Aare, Stephanie Stoughton, Anvar Zakhidov, and Ray Baughman, The University of Texas at Dallas / Alan G. MacDiarmid NanoTech Institute.

  18. Affecting Factors and Outcome on Intermittent Internet Pulling Behavior in Taiwan's Undergraduate Students

    ERIC Educational Resources Information Center

    Yang, Hui-Jen; Lay, Yun-Long

    2011-01-01

    Nowadays people's lives heavily rely on Internet facilities. Internet users generally have constant Internet connectivity and intermittently click on sites they want to access even amidst studying or working. In this study, we sought to examine the factors affecting intermittent Internet pulling behavior on undergraduate students. Furthermore, the…

  19. Effect of twist on transverse impact response of ballistic fiber yarns

    DOE PAGES

    Song, Bo; Lu, Wei -Yang

    2015-06-15

    A Hopkinson bar was employed to conduct transverse impact testing of twisted Kevlar KM2 fiber yarns at the same impact speed. The speed of Euler transverse wave generated by the impact was measured utilizing a high speed digital camera. The study included fiber yarns twisted by different amounts. The Euler transverse wave speed was observed to increase with increasing amount of twist of the fiber yarn, within the range of this investigation. As a result, the higher transverse wave speeds in the more twisted fiber yarns indicate better ballistic performance in soft body armors for personal protection.

  20. Superaligned carbon nanotube arrays, films, and yarns: a road to applications.

    PubMed

    Jiang, Kaili; Wang, Jiaping; Li, Qunqing; Liu, Liang; Li, Changhong; Fan, Shoushan

    2011-03-04

    A superaligned carbon nanotube (CNT) array is a special kind of vertically aligned CNT array with the capability of being converted into continuous fi lms and yarns. The as-produced CNT fi lms are transparent and highly conductive, with aligned CNTs parallel to the direction of drawing. After passing through volatile solutions or being twisted, CNT fi lms can be further condensed into shrunk yarns. These shrunk yarns possess high tensile strengths and Young’s moduli, and are good conductors. Many applications of CNT fi lms and shrunk yarns have been demonstrated, such as TEM grids, loudspeakers, touch screens, etc.

  1. Is trichotillomania a stereotypic movement disorder? An analysis of body-focused repetitive behaviors in people with hair-pulling.

    PubMed

    Stein, Dan J; Flessner, Christopher A; Franklin, Martin; Keuthen, Nancy J; Lochner, Christine; Woods, Douglas W

    2008-01-01

    Stereotypic movement disorder (SMD) is characterized by nonfunctional repetitive movements, is typically diagnosed in people with intellectual disability, and by definition excludes people with trichotillomania (TTM). Nevertheless, hair-pulling may be one of a number of body-focused repetitive behaviors (BFRBs) that are seen in the general population. Comorbidity of symptoms might support the idea that they are indicative of an underlying stereotypic disorder, and we therefore explored their frequency in people with hair-pulling. Participants were recruited with the help of the Trichotillomania Learning Center, the largest advocacy group for people with hair-pulling. Participants completed a self-report survey on the Internet, which included questions about the presence of both hair-pulling and other BFRBs. Measures included the Massachusetts General Hospital Hairpulling Scale (MGH-HS), the Milwaukee Inventory for Subtypes of Trichotillomania-Adult Version (MIST-A), the Depression and Anxiety Stress Scale (DASS), and the Sheehan Disability Scale (SDS). The majority of participants with hair-pulling (70%) report the presence of other BFRBs, most commonly skin-picking and nail-biting. There were particularly strong associations between the total number of BFRBs and increased scores on ratings of focused hair-pulling, depression, anxiety, stress, and functional impairment. Similar results were found in participants who met more rigorous criteria for trichotillomania. This study is limited by its self-report nature, and by the lack of detailed information on the phenomenology of comorbid BFRBs. While further nosological research is needed, the high rates of these behaviors in people with hair-pulling, and their association with increased disability, is consistent with previous clinical observations, and supports the argument that trichotillomania can usefully be conceptualized as a stereotypic disorder. Speculatively, this argument may be especially valid in

  2. Regenerative braking systems with torsional springs made of carbon nanotube yarn

    NASA Astrophysics Data System (ADS)

    Liu, S.; Martin, C.; Lashmore, D.; Schauer, M.; Livermore, C.

    2014-11-01

    The demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as an energy-storing actuator for regenerative braking systems. Originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing until failure. The maximum extractable energy density is measured to be as high as 6.13 kJ/kg. The tests also reveal structural reorganization and hysteresis in the torsional loading curves. A regenerative braking system is built to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yam's twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking system are up to 4.69 kJ/kg and 1.21 kW/kg, respectively. A slightly lower energy density of up to 1.23 kJ/kg and a 0.29 kW/kg mean power density are measured for the CNT yarns in a more complex system that mimics a unidirectional rotating regenerative braking mechanism. The lower energy densities for CNT yarns in the regenerative braking systems as compared with the yarns themselves reflect the frictional losses of the regenerative systems.

  3. Thermo-Mechanical Behavior of Textile Heating Fabric Based on Silver Coated Polymeric Yarn

    PubMed Central

    Hamdani, Syed Talha Ali; Potluri, Prasad; Fernando, Anura

    2013-01-01

    This paper presents a study conducted on the thermo-mechanical properties of knitted structures, the methods of manufacture, effect of contact pressure at the structural binding points, on the degree of heating. The test results also present the level of heating produced as a function of the separation between the supply terminals. The study further investigates the rate of heating and cooling of the knitted structures. The work also presents the decay of heating properties of the yarn due to overheating. Thermal images were taken to study the heat distribution over the surface of the knitted fabric. A tensile tester having constant rate of extension was used to stretch the fabric. The behavior of temperature profile of stretched fabric was observed. A comparison of heat generation by plain, rib and interlock structures was studied. It was observed from the series of experiments that there is a minimum threshold force of contact at binding points of a knitted structure is required to pass the electricity. Once this force is achieved, stretching the fabric does not affect the amount of heat produced. PMID:28809358

  4. Analyzing the Effect of Spinning Process Variables on Draw Frame Blended Cotton Mélange Yarn Quality

    NASA Astrophysics Data System (ADS)

    Ray, Suchibrata; Ghosh, Anindya; Banerjee, Debamalya

    2018-06-01

    An investigation has been made to study the effect of important spinning process variables namely shade depth, ring frame spindle speed and yarn twist multiplier (TM) on various yarn quality parameters like unevenness, strength, imperfection, elongation at break and hairiness index of draw frame blended cotton mélange yarn. Three factors Box and Behnken design of experiment has been used to conduct the study. The quadratic regression model is used to device the statistical inferences about sensitivity of the yarn quality parameters to the different process variables. The response surfaces are constructed for depicting the geometric representation of yarn quality parameters plotted as a function of process variables. Analysis of the results show that yarn strength of draw frame blended cotton mélange yarn is significantly affected by shade depth and TM. Yarn unevenness is affected by shade depth and ring frame spindle speed. Yarn imperfection level is mainly influenced by the shade depth and spindle speed. The shade depth and yarn TM have shown significant impact on yarn hairiness index.

  5. Analyzing the Effect of Spinning Process Variables on Draw Frame Blended Cotton Mélange Yarn Quality

    NASA Astrophysics Data System (ADS)

    Ray, Suchibrata; Ghosh, Anindya; Banerjee, Debamalya

    2017-12-01

    An investigation has been made to study the effect of important spinning process variables namely shade depth, ring frame spindle speed and yarn twist multiplier (TM) on various yarn quality parameters like unevenness, strength, imperfection, elongation at break and hairiness index of draw frame blended cotton mélange yarn. Three factors Box and Behnken design of experiment has been used to conduct the study. The quadratic regression model is used to device the statistical inferences about sensitivity of the yarn quality parameters to the different process variables. The response surfaces are constructed for depicting the geometric representation of yarn quality parameters plotted as a function of process variables. Analysis of the results show that yarn strength of draw frame blended cotton mélange yarn is significantly affected by shade depth and TM. Yarn unevenness is affected by shade depth and ring frame spindle speed. Yarn imperfection level is mainly influenced by the shade depth and spindle speed. The shade depth and yarn TM have shown significant impact on yarn hairiness index.

  6. Ultrafast charge and discharge biscrolled yarn supercapacitors for textiles and microdevices

    NASA Astrophysics Data System (ADS)

    Lee, Jae Ah; Shin, Min Kyoon; Kim, Shi Hyeong; Cho, Hyun U.; Spinks, Geoffrey M.; Wallace, Gordon G.; Lima, Márcio D.; Lepró, Xavier; Kozlov, Mikhail E.; Baughman, Ray H.; Kim, Seon Jeong

    2013-06-01

    Flexible, wearable, implantable and easily reconfigurable supercapacitors delivering high energy and power densities are needed for electronic devices. Here we demonstrate weavable, sewable, knottable and braidable yarns that function as high performance electrodes of redox supercapacitors. A novel technology, gradient biscrolling, provides fast-ion-transport yarn in which hundreds of layers of conducting-polymer-infiltrated carbon nanotube sheet are scrolled into ~20 μm diameter yarn. Plying the biscrolled yarn with a metal wire current collector increases power generation capabilities. The volumetric capacitance is high (up to ~179 F cm-3) and the discharge current of the plied yarn supercapacitor linearly increases with voltage scan rate up to ~80 V s-1 and ~20 V s-1 for liquid and solid electrolytes, respectively. The exceptionally high energy and power densities for the complete supercapacitor, and high cycle life that little depends on winding or sewing (92%, 99% after 10,000 cycles, respectively) are important for the applications in electronic textiles.

  7. Cervical anterior transpedicular screw fixation (ATPS)—Part II. Accuracy of manual insertion and pull-out strength of ATPS

    PubMed Central

    Acosta, Frank; Tauber, Mark; Fox, Michael; Martin, Hudelmaier; Forstner, Rosmarie; Augat, Peter; Penzkofer, Rainer; Pirich, Christian; Kässmann, H.; Resch, Herbert; Hitzl, Wolfgang

    2008-01-01

    Reconstruction after multilevel decompression of the cervical spine, especially in the weakened osteoporotic, neoplastic or infectious spine often requires circumferential stabilization and fusion. To avoid the additional posterior surgery in these cases while increasing rigidity of anterior-only screw-plate constructs, the authors introduce the concept of anterior transpedicular screw (ATPS) fixation. We demonstrated its morphological feasibility as well as its indications in a previous study in Part I of our project. Consequently, the objectives of the current study were to assess the ex vivo accuracy of placing ATPS into the cervical vertebra as well as the biomechanical performance of ATPS in comparison to traditional vertebral body screws (VBS) in terms of pull-out strength (POS). Twenty-three ATPS were inserted alternately to two screws into the pedicles and vertebral bodies, respectively, of six cadaveric specimens from C3–T1. For insertion of ATPS, a manual fluoroscopically assisted technique was used. Pre- and post insertional CT-scans were used to assess accuracy of ATPS insertion in the axial and sagittal planes. A newly designed grading system and accuracy score were used to delineate accuracy of ATPS insertion. Following insertion of screws, 23 ATPS and 22 VBS were subjected to pull-out testing (POT). The bone mineral density (BMD) of each specimen was assessed prior to POT. Statistical analysis showed that the incidence of correctly placed screws and non-critical pedicles breaches in axial plane was 78.3%, and 95.7% in sagittal plane. Hence, according to our definition of “critical” pedicle breach that exposes neurovascular structures at risk, 21.7% (n = 5) of all ATPS inserted showed a critical pedicle breach in axial plane. Notably, no critical pedicle perforation occurred at the C6 to T1 levels. Pull-out testing of ATPS and VBS revealed that pull-out resistance of ATPS was 2.5-fold that of VBS. Mean POS of 23 ATPS with a mean BMD of 0.566

  8. Using three-dimensional rapid prototyping in the design and development of orthopaedic screws in standardised pull-out tests.

    PubMed

    Leslie, Laura Jane; Connolly, Ashley; Swadener, John G; Junaid, Sarah; Theivendran, Kanthan; Deshmukh, Subodh C

    2018-06-01

    The majority of orthopaedic screws are designed, tested and manufactured by existing orthopaedics companies and are predominantly developed with healthy bone in mind. The timescales and costs involved in the development of a new screw design, for example, for osteoporotic bone, are high. In this study, standard wood screws were used to analyse the concept of using three-dimensional printing, or rapid prototyping, as a viable stage of development in the design of a new bone screw. Six wood screws were reverse engineered and printed in polymeric material using stereolithography. Three of the designs were also printed in Ti6Al4V using direct metal laser sintering; however, these were not of sufficient quality to test further. Both the original metal screws (metal) and polymeric rapid prototyping screws were then tested using standard pull-out tests from low-density polyurethane blocks (Sawbones). Results showed the highest pull-out strengths for screws with the longest thread length and the smallest inner diameter. Of the six screw designs tested, five showed no more than a 17% variance between the metal and rapid prototyping results. A similar pattern of results was shown between the screw designs for both the metal and rapid prototyping screws in five of the six cases. While not producing fully comparable pull-out results to orthopaedic screws, the results from this study do provide evidence of the potential usefulness and cost-effectiveness of rapid prototyping in the early stages of design and testing of orthopaedic screws.

  9. Yo-Yo Pull Demonstration

    ERIC Educational Resources Information Center

    Layton, William

    2013-01-01

    A popular demonstration involves placing a yo-yo on a level table and gently pulling the string horizontally when it is wrapped to come out below the center of the yo-yo's axis. Students are then asked to predict which way the yo-yo will move. A similar demonstration is performed with a tricycle by pulling forward on a pedal with the pedal down in…

  10. Structure and yarn sensor for fabric

    DOEpatents

    Mee, David K.; Allgood, Glenn O.; Mooney, Larry R.; Duncan, Michael G.; Turner, John C.; Treece, Dale A.

    1998-01-01

    A structure and yarn sensor for fabric directly determines pick density in a fabric thereby allowing fabric length and velocity to be calculated from a count of the picks made by the sensor over known time intervals. The structure and yarn sensor is also capable of detecting full length woven defects and fabric. As a result, an inexpensive on-line pick (or course) density measurement can be performed which allows a loom or knitting machine to be adjusted by either manual or automatic means to maintain closer fiber density tolerances. Such a sensor apparatus dramatically reduces fabric production costs and significantly improves fabric consistency and quality for woven or knitted fabric.

  11. Origin of tensile strength of a woven sample cut in bias directions

    PubMed Central

    Pan, Ning; Kovar, Radko; Dolatabadi, Mehdi Kamali; Wang, Ping; Zhang, Diantang; Sun, Ying; Chen, Li

    2015-01-01

    Textile fabrics are highly anisotropic, so that their mechanical properties including strengths are a function of direction. An extreme case is when a woven fabric sample is cut in such a way where the bias angle and hence the tension loading direction is around 45° relative to the principal directions. Then, once loaded, no yarn in the sample is held at both ends, so the yarns have to build up their internal tension entirely via yarn–yarn friction at the interlacing points. The overall fabric strength in such a sample is a result of contributions from the yarns being pulled out and those broken during the process, and thus becomes a function of the bias direction angle θ, sample width W and length L, along with other factors known to affect fabric strength tested in principal directions. Furthermore, in such a bias sample when the major parameters, e.g. the sample width W, change, not only the resultant strengths differ, but also the strength generating mechanisms (or failure types) vary. This is an interesting problem and is analysed in this study. More specifically, the issues examined in this paper include the exact mechanisms and details of how each interlacing point imparts the frictional constraint for a yarn to acquire tension to the level of its strength when both yarn ends were not actively held by the testing grips; the theoretical expression of the critical yarn length for a yarn to be able to break rather than be pulled out, as a function of the related factors; and the general relations between the tensile strength of such a bias sample and its structural properties. At the end, theoretical predictions are compared with our experimental data. PMID:26064655

  12. Machine-Washable PEDOT:PSS Dyed Silk Yarns for Electronic Textiles.

    PubMed

    Ryan, Jason D; Mengistie, Desalegn Alemu; Gabrielsson, Roger; Lund, Anja; Müller, Christian

    2017-03-15

    Durable, electrically conducting yarns are a critical component of electronic textiles (e-textiles). Here, such yarns with exceptional wear and wash resistance are realized through dyeing silk from the silkworm Bombyx mori with the conjugated polymer:polyelectrolyte complex PEDOT:PSS. A high Young's modulus of approximately 2 GPa combined with a robust and scalable dyeing process results in up to 40 m long yarns that maintain their bulk electrical conductivity of approximately 14 S cm -1 when experiencing repeated bending stress as well as mechanical wear during sewing. Moreover, a high degree of ambient stability is paired with the ability to withstand both machine washing and dry cleaning. For the potential use for e-textile applications to be illustrated, an in-plane thermoelectric module that comprises 26 p-type legs is demonstrated by embroidery of dyed silk yarns onto a piece of felted wool fabric.

  13. Machine-Washable PEDOT:PSS Dyed Silk Yarns for Electronic Textiles

    PubMed Central

    2017-01-01

    Durable, electrically conducting yarns are a critical component of electronic textiles (e-textiles). Here, such yarns with exceptional wear and wash resistance are realized through dyeing silk from the silkworm Bombyx mori with the conjugated polymer:polyelectrolyte complex PEDOT:PSS. A high Young’s modulus of approximately 2 GPa combined with a robust and scalable dyeing process results in up to 40 m long yarns that maintain their bulk electrical conductivity of approximately 14 S cm–1 when experiencing repeated bending stress as well as mechanical wear during sewing. Moreover, a high degree of ambient stability is paired with the ability to withstand both machine washing and dry cleaning. For the potential use for e-textile applications to be illustrated, an in-plane thermoelectric module that comprises 26 p-type legs is demonstrated by embroidery of dyed silk yarns onto a piece of felted wool fabric. PMID:28245105

  14. Thermoplastic-carbon fiber hybrid yarn

    NASA Technical Reports Server (NTRS)

    Ketterer, M. E.

    1984-01-01

    Efforts were directed to develop processing methods to make carbon fiber/thermoplastic fiber preforms that are easy to handle and drapeable, and to consolidate them into low void content laminates. The objectives were attained with the development of the hybrid yarn concept; whereby, thermoplastic fiber can be intimately intermixed with carbon fiber into a hybrid yarn. This was demonstrated with the intermixing of Celion 3000 with a Celanese liquid crystal polymer fiber, polybutylene terepthalate fiber, or polyetheretherketone fiber. The intermixing of the thermoplastic matrix fiber and the reinforcing carbon fiber gives a preform that can be easily fabricated into laminates with low void content. Mechanical properties of the laminates were not optimized; however, initial results indicated properties typical of a thermoplastic/carbon fiber composites prepared by more conventional methods.

  15. Multi Objective Optimization of Yarn Quality and Fibre Quality Using Evolutionary Algorithm

    NASA Astrophysics Data System (ADS)

    Ghosh, Anindya; Das, Subhasis; Banerjee, Debamalya

    2013-03-01

    The quality and cost of resulting yarn play a significant role to determine its end application. The challenging task of any spinner lies in producing a good quality yarn with added cost benefit. The present work does a multi-objective optimization on two objectives, viz. maximization of cotton yarn strength and minimization of raw material quality. The first objective function has been formulated based on the artificial neural network input-output relation between cotton fibre properties and yarn strength. The second objective function is formulated with the well known regression equation of spinning consistency index. It is obvious that these two objectives are conflicting in nature i.e. not a single combination of cotton fibre parameters does exist which produce maximum yarn strength and minimum cotton fibre quality simultaneously. Therefore, it has several optimal solutions from which a trade-off is needed depending upon the requirement of user. In this work, the optimal solutions are obtained with an elitist multi-objective evolutionary algorithm based on Non-dominated Sorting Genetic Algorithm II (NSGA-II). These optimum solutions may lead to the efficient exploitation of raw materials to produce better quality yarns at low costs.

  16. Differential lead component pulling as a possible mechanism of inside-out abrasion and conductor cable externalization.

    PubMed

    Lau, Ernest W

    2013-09-01

    Conductor cable externalization with protrusion (CCE*) is highly prevalent among the Riata 8F and ST 7F defibrillation (DF) leads and infrequently present in the QuickSite and the QuickFlex coronary sinus (CS) leads (St. Jude Medical, Sylmar, CA, USA). A model for CCE* based on differential lead component pulling and conjugate extension with reciprocal compression-bending was developed. Extension of a proximal lead body segment by pectoral or cardiac movements causes reciprocal compression-bending of a distal lead body segment mediated by inextensible conductor cables running down a lead body fixed at various points by fibrous adhesions. The "sawing" action of these cables under tension causes inside-out abrasion of insulation leading to CCE*. DF leads from different manufacturers and the QuickFlex and QuickFlex μ CS leads were subjected to simulated differential pulling. Restitution from differential pulling followed three patterns: complete, partial without escalation, and incomplete with escalation. Only the last pattern (only shown by the Riata 8F and ST 7F leads) was associated with an increased risk to CCE*. For CS leads, deformation concentrated on the more flexible segment when the lead body did not have a uniform construction. The Durata, Riata ST Optim, QuickFlex μ, and Quartet leads should be relatively immune to CCE*. The Durata leads are extremely resistant to longitudinal deformation and probably cause mediastinal displacement rather than differential pulling in response to pectoral movements in vivo. Implantation techniques and lead designs can be used to minimize the risk of CCE*. A bench test for CCE* can be constructed. ©2013, The Author. Journal compilation ©2013 Wiley Periodicals, Inc.

  17. High-performance two-ply yarn supercapacitors based on carbon nanotubes and polyaniline nanowire arrays.

    PubMed

    Wang, Kai; Meng, Qinghai; Zhang, Yajie; Wei, Zhixiang; Miao, Menghe

    2013-03-13

    Fine count two-ply yarn supercapacitors are constructed from carbon nanotube yarns and polyaniline nanowires. The thread-like supercapacitor possess excellent electrochemical capacity and are very strong and flexible. When being woven or knitted into wearable electronic devices, alone or in combination with conventional textile yarns, the two-ply yarn supercapacitors can be flexed and stretched repeatedly without significant loss of capacitance. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Single-step process to improve the mechanical properties of carbon nanotube yarn.

    PubMed

    Evora, Maria Cecilia; Lu, Xinyi; Hiremath, Nitilaksha; Kang, Nam-Goo; Hong, Kunlun; Uribe, Roberto; Bhat, Gajanan; Mays, Jimmy

    2018-01-01

    Carbon nanotube (CNT) yarns exhibit low tensile strength compared to conventional high-performance carbon fibers due to the facile sliding of CNTs past one another. Electron beam (e-beam) irradiation was employed for in a single-step surface modification of CNTs to improve the mechanical properties of this material. To this end, CNT yarns were simultaneously functionalized and crosslinked using acrylic acid (AA) and acrylonitrile (AN) in an e-beam irradiation process. The chemical modification of CNT yarns was confirmed by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and scanning electron microscopy (SEM). The best improvement in mechanical properties was achieved on a sample treated with an aqueous solution of AA and subsequent irradiation. CNT yarn treatment with AA enhanced the strength (444.5 ± 68.4 MPa) by more than 75% and the modulus (21.5 ± 0.6 GPa) by more than 144% as compared to untreated CNT yarn (strength 251 ± 26.5 MPa and modulus 8.8 ± 1.2 GPa).

  19. Single-step process to improve the mechanical properties of carbon nanotube yarn

    PubMed Central

    Lu, Xinyi; Hiremath, Nitilaksha; Kang, Nam-Goo; Hong, Kunlun; Uribe, Roberto; Bhat, Gajanan; Mays, Jimmy

    2018-01-01

    Carbon nanotube (CNT) yarns exhibit low tensile strength compared to conventional high-performance carbon fibers due to the facile sliding of CNTs past one another. Electron beam (e-beam) irradiation was employed for in a single-step surface modification of CNTs to improve the mechanical properties of this material. To this end, CNT yarns were simultaneously functionalized and crosslinked using acrylic acid (AA) and acrylonitrile (AN) in an e-beam irradiation process. The chemical modification of CNT yarns was confirmed by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and scanning electron microscopy (SEM). The best improvement in mechanical properties was achieved on a sample treated with an aqueous solution of AA and subsequent irradiation. CNT yarn treatment with AA enhanced the strength (444.5 ± 68.4 MPa) by more than 75% and the modulus (21.5 ± 0.6 GPa) by more than 144% as compared to untreated CNT yarn (strength 251 ± 26.5 MPa and modulus 8.8 ± 1.2 GPa). PMID:29527431

  20. Yo-yo Pull Demonstration

    NASA Astrophysics Data System (ADS)

    Layton, William

    2013-03-01

    A popular demonstration involves placing a yo-yo on a level table and gently pulling the string horizontally when it is wrapped to come out below the center of the yo-yo's axis. Students are then asked to predict which way the yo-yo will move. A similar demonstration is performed with a tricycle by pulling forward on a pedal with the pedal down in its lowest position.2,3 As well as pulling the yo-yo horizontally, often the string is lifted until the angle it makes with the table causes no motion. This occurs when the line extended from the string intersects the point of contact of the yo-yo with the table.4 This paper describes an apparatus that extends these demonstrations to the situation where the force pulling the yo-yo is still horizontal yet is below the level of the table.

  1. Structure and yarn sensor for fabric

    DOEpatents

    Mee, D.K.; Allgood, G.O.; Mooney, L.R.; Duncan, M.G.; Turner, J.C.; Treece, D.A.

    1998-10-20

    A structure and yarn sensor for fabric directly determines pick density in a fabric thereby allowing fabric length and velocity to be calculated from a count of the picks made by the sensor over known time intervals. The structure and yarn sensor is also capable of detecting full length woven defects and fabric. As a result, an inexpensive on-line pick (or course) density measurement can be performed which allows a loom or knitting machine to be adjusted by either manual or automatic means to maintain closer fiber density tolerances. Such a sensor apparatus dramatically reduces fabric production costs and significantly improves fabric consistency and quality for woven or knitted fabric. 13 figs.

  2. Dwindling the resistance value of PEDOT:PSS – coated on fabric yarns

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

    Amba Sankar, K.N., E-mail: amb@psgias.ac.in; Kallol, Mohanta

    2016-05-23

    Herein we describe by dip coating method to transform typical fabric yarn to conductive fiber. Different types of yarns have been used to coat from a known conductive polymer, Poly (3,4ethylenedioxythiophene) Poly (styrene sulfonic acid). We have optimized the method to have lesser resistance of the conductive yarns. The minimum resistance achieved has a value of 77 Ω/cm. This value is not high as metals but could be comparable to that of metal oxides or semiconducting materials. However, flexibility of yarns and feeling of fabric combining with the conductivity developed in this process is suitable for wearable electronics and alsomore » as gas sensors, electromagnetic shielding.« less

  3. Investigation on the Yarn Squeezing Effect of Three Dimensional Full Five Directional Braided Composites

    NASA Astrophysics Data System (ADS)

    Hu, Long; Tao, Guoquan; Liu, Zhenguo; Wang, Yibo; Ya, Jixuan

    2018-04-01

    The influence of yarn squeezing effect on the geometric morphology and mechanical property of the three dimensional full five directional (3DF5D) braided composites is explored. Spatial path and cross-section shape of the yarns in the braided structure are characterized based on the micro computed tomography (micro CT) scanning images. The yarn distortion due to the squeezing effect is discussed and mathematical morphology of the yarn geometry is established. A new repeated unit cell (RUC) model of 3DF5D braided composites considering yarn squeezing effect is developed. Based on this model, mechanical properties of 3DF5D braided composites are analyzed. Good agreement is obtained between the predicted and experiment results. Moreover, the stress distribution of the new RUC model are compared with original RUC model, showing that the squeezing effect significantly increases the stress concentration level of the axial yarns.

  4. Vision-based in-line fabric defect detection using yarn-specific shape features

    NASA Astrophysics Data System (ADS)

    Schneider, Dorian; Aach, Til

    2012-01-01

    We develop a methodology for automatic in-line flaw detection in industrial woven fabrics. Where state of the art detection algorithms apply texture analysis methods to operate on low-resolved ({200 ppi) image data, we describe here a process flow to segment single yarns in high-resolved ({1000 ppi) textile images. Four yarn shape features are extracted, allowing a precise detection and measurement of defects. The degree of precision reached allows a classification of detected defects according to their nature, providing an innovation in the field of automatic fabric flaw detection. The design has been carried out to meet real time requirements and face adverse conditions caused by loom vibrations and dirt. The entire process flow is discussed followed by an evaluation using a database with real-life industrial fabric images. This work pertains to the construction of an on-loom defect detection system to be used in manufacturing practice.

  5. Modifying friction between ultra-high molecular weight polyethylene (UHMWPE) yarns with plasma enhanced chemical vapour deposition (PCVD)

    NASA Astrophysics Data System (ADS)

    Chu, Yanyan; Chen, Xiaogang; Tian, Lipeng

    2017-06-01

    Ultra-high molecular weight polyethylene (UHMWPE) yarns are widely used in military applications for protection owing to its high modulus and high strength; however, the friction between UHMWPE yarns is too small, which is a weakness for ballistic applications. The purpose of current research is to increase the friction between UHMWPE yarns by plasma enhanced chemical vapour deposition (PCVD). The changes of morphology and chemical structure were characterised by SEM and FTIR individually. The coefficients of friction between yarns were tested by means of Capstan method. Results from tests showed that the yarn-yarn coefficient of static friction (CSF) has been improved from 0.12 to 0.23 and that of kinetic friction (CSF) increased from 0.11 to 0.19, as the samples exposure from 21 s to 4 min. The more inter-yarn friction can be attributed to more and more particles and more polar groups deposited on the surfaces of yarns, including carboxyl, carbonyl, hydroxyl and amine groups and compounds containing silicon. The tensile strength and modulus of yarns, which are essential to ballistic performance, keep stable and are not affected by the treatments, indicating that PCVD treatment is an effective way to improve the inter-yarn friction without mechanical property degradation.

  6. Prognostic factors of arthroscopic pull-out repair for a posterior root tear of the medial meniscus.

    PubMed

    Moon, Hong-Kyo; Koh, Yong-Gon; Kim, Yong-Chan; Park, Young-Sik; Jo, Seung-Bae; Kwon, Sae-Kwang

    2012-05-01

    Repair of a posterior root tear of the medial meniscus (MRT) decreases peak contact pressure by restoring hoop tension and is expected to prevent progression to osteoarthritis. The purposes of this study were (1) to report the clinical and magnetic resonance imaging (MRI) results of arthroscopic pull-out repair of the MRT and (2) to identify prognostic factors of poor outcome. Case series; Level of evidence, 4. Fifty-one patients (47 women, 4 men) who underwent arthroscopic pull-out repair of the MRT by a single surgeon were enrolled. Mean follow-up after surgery was 33 months (range, 24-44 months). To identify factors affecting final outcome, patient-specific factors, such as gender, age, body mass index, meniscus extrusion, extrusion increase, subchondral edema, degree of varus alignment (<5° or >5°), and cartilage status in the medial compartment (Outerbridge grade 1 or 2 lesion vs grade 3 or 4 lesion), were investigated. Final clinical outcomes were determined using a visual analog scale (VAS) for pain and patient satisfaction scores, American Knee Society (AKS) scores, and Lysholm scores, and MRI outcomes were determined by evaluating meniscus extrusion and articular cartilage status. Multiple regression analysis was performed to identify variables that independently affected clinical and MRI-determined outcomes. All clinical outcome measures significantly improved after surgery. Patients with Outerbridge grade 3 or 4 chondral lesions had poorer results than those with grade 1 or 2 lesions in terms of AKS function and Lysholm scores. Patients with varus alignment of >5° had poorer results than those with varus alignment of <5° in terms of VAS satisfaction, AKS function, and Lysholm scores. Mean meniscus extrusion increased from 3.6 mm preoperatively to 5.0 mm postoperatively. Chondral lesions progressed in 3 (9.7%) of 31 patients. Preoperative meniscus extrusion was found to be positively correlated with final extrusion. At a mean follow-up of 33 months

  7. Hollow Polypropylene Yarns as a Biomimetic Brain Phantom for the Validation of High-Definition Fiber Tractography Imaging.

    PubMed

    Guise, Catarina; Fernandes, Margarida M; Nóbrega, João M; Pathak, Sudhir; Schneider, Walter; Fangueiro, Raul

    2016-11-09

    Current brain imaging methods largely fail to provide detailed information about the location and severity of axonal injuries and do not anticipate recovery of the patients with traumatic brain injury. High-definition fiber tractography appears as a novel imaging modality based on water motion in the brain that allows for direct visualization and quantification of the degree of axons damage, thus predicting the functional deficits due to traumatic axonal injury and loss of cortical projections. This neuroimaging modality still faces major challenges because it lacks a "gold standard" for the technique validation and respective quality control. The present work aims to study the potential of hollow polypropylene yarns to mimic human white matter axons and construct a brain phantom for the calibration and validation of brain diffusion techniques based on magnetic resonance imaging, including high-definition fiber tractography imaging. Hollow multifilament polypropylene yarns were produced by melt-spinning process and characterized in terms of their physicochemical properties. Scanning electronic microscopy images of the filaments cross section has shown an inner diameter of approximately 12 μm, confirming their appropriateness to mimic the brain axons. The chemical purity of polypropylene yarns as well as the interaction between the water and the filament surface, important properties for predicting water behavior and diffusion inside the yarns, were also evaluated. Restricted and hindered water diffusion was confirmed by fluorescence microscopy. Finally, the yarns were magnetic resonance imaging scanned and analyzed using high-definition fiber tractography, revealing an excellent choice of these hollow polypropylene structures for simulation of the white matter brain axons and their suitability for constructing an accurate brain phantom.

  8. Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics

    NASA Astrophysics Data System (ADS)

    Kou, Liang; Huang, Tieqi; Zheng, Bingna; Han, Yi; Zhao, Xiaoli; Gopalsamy, Karthikeyan; Sun, Haiyan; Gao, Chao

    2014-05-01

    Yarn supercapacitors have great potential in future portable and wearable electronics because of their tiny volume, flexibility and weavability. However, low-energy density limits their development in the area of wearable high-energy density devices. How to enhance their energy densities while retaining their high-power densities is a critical challenge for yarn supercapacitor development. Here we propose a coaxial wet-spinning assembly approach to continuously spin polyelectrolyte-wrapped graphene/carbon nanotube core-sheath fibres, which are used directly as safe electrodes to assembly two-ply yarn supercapacitors. The yarn supercapacitors using liquid and solid electrolytes show ultra-high capacitances of 269 and 177 mF cm-2 and energy densities of 5.91 and 3.84 μWh cm-2, respectively. A cloth supercapacitor superior to commercial capacitor is further interwoven from two individual 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and excellent performance of yarn supercapacitors paves the way to wearable and safe electronics.

  9. Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics

    PubMed Central

    Kou, Liang; Huang, Tieqi; Zheng, Bingna; Han, Yi; Zhao, Xiaoli; Gopalsamy, Karthikeyan; Sun, Haiyan; Gao, Chao

    2014-01-01

    Yarn supercapacitors have great potential in future portable and wearable electronics because of their tiny volume, flexibility and weavability. However, low-energy density limits their development in the area of wearable high-energy density devices. How to enhance their energy densities while retaining their high-power densities is a critical challenge for yarn supercapacitor development. Here we propose a coaxial wet-spinning assembly approach to continuously spin polyelectrolyte-wrapped graphene/carbon nanotube core-sheath fibres, which are used directly as safe electrodes to assembly two-ply yarn supercapacitors. The yarn supercapacitors using liquid and solid electrolytes show ultra-high capacitances of 269 and 177 mF cm−2 and energy densities of 5.91 and 3.84 μWh cm−2, respectively. A cloth supercapacitor superior to commercial capacitor is further interwoven from two individual 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and excellent performance of yarn supercapacitors paves the way to wearable and safe electronics. PMID:24786366

  10. Investigation of the electrical characteristics of electrically conducting yarns and fabrics

    NASA Astrophysics Data System (ADS)

    Akbarov, R. D.; Baymuratov, B. H.; Akbarov, D. N.; Ilhamova, M.

    2017-11-01

    Electro-conductive textile materials and products are used presently giving solutions to the problems, related to static electricity, electromagnetic shielding and electromagnetic radiation. Thus a study of their electro-physical characteristics, character of conductivity, possibility of forecasting of electric parameters etc has a substantial value. This work shows the possibility of production electro-conducting textile materials with stable anti-static properties by introduction of electro-conducting yarn into the structure of fabrics. The results of the research, directed to the study of the electro-physical characteristics of electroconducting yarn and fabrics, are influenced by the frequent washing of polyester fabrics containing the different amounts of electro-conducting filaments in the composition. This article reviews the results of the related research, of the electrical characteristics of the yarn and fabric, of the effect of multiple water treatments on the electrical properties of polyester fabrics, containing in their composition different amounts of electrically conductive yarns.

  11. Fabrication and processing of high-strength densely packed carbon nanotube yarns without solution processes.

    PubMed

    Liu, Kai; Zhu, Feng; Liu, Liang; Sun, Yinghui; Fan, Shoushan; Jiang, Kaili

    2012-06-07

    Defects of carbon nanotubes, weak tube-tube interactions, and weak carbon nanotube joints are bottlenecks for obtaining high-strength carbon nanotube yarns. Some solution processes are usually required to overcome these drawbacks. Here we fabricate ultra-long and densely packed pure carbon nanotube yarns by a two-rotator twisting setup with the aid of some tensioning rods. The densely packed structure enhances the tube-tube interactions, thus making high tensile strengths of carbon nanotube yarns up to 1.6 GPa. We further use a sweeping laser to thermally treat as-produced yarns for recovering defects of carbon nanotubes and possibly welding carbon nanotube joints, which improves their Young's modulus by up to ∼70%. The spinning and laser sweeping processes are solution-free and capable of being assembled together to produce high-strength yarns continuously as desired.

  12. Developing an Acoustic Sensing Yarn for Health Surveillance in a Military Setting.

    PubMed

    Hughes-Riley, Theodore; Dias, Tilak

    2018-05-17

    Overexposure to high levels of noise can cause permanent hearing disorders, which have a significant adverse effect on the quality of life of those affected. Injury due to noise can affect people in a variety of careers including construction workers, factory workers, and members of the armed forces. By monitoring the noise exposure of workers, overexposure can be avoided and suitable protective equipment can be provided. This work focused on the creation of a noise dosimeter suitable for use by members of the armed forces, where a discrete dosimeter was integrated into a textile helmet cover. In this way the sensing elements could be incorporated very close to the ears, providing a highly representative indication of the sound level entering the body, and also creating a device that would not interfere with military activities. This was achieved by utilising commercial microelectromechanical system microphones integrated within the fibres of yarn to create an acoustic sensing yarn. The acoustic sensing yarns were fully characterised over a range of relevant sound levels and frequencies at each stage in the yarn production process. The yarns were ultimately integrated into a knitted helmet cover to create a functional acoustic sensing helmet cover prototype.

  13. Peer Attitudes toward Students with Disabilities: A Comparison of the In-Class and Pull-Out Models of Service Delivery.

    ERIC Educational Resources Information Center

    Noland, Emily N.; And Others

    1993-01-01

    This study compared the differential effects of in-class and pull-out service delivery models on attitudes of students (n=194) in grades four through six toward students with disabilities. Results revealed that students from classrooms where services were being delivered through in-class service delivery models had more positive attitudes.…

  14. Drawbar Pull

    DTIC Science & Technology

    2017-01-26

    Includes procedures for hard surface, soil , and water tests. Discusses vehicle preparation, instrumentation method of computing results, data reduction...and amphibious vehicles. 15. SUBJECT TERMS Bollard pull Soft- soil mobility Drawbar pull Vehicle, amphibious Drawbar horsepower Vehicle...4.3 Drawbar Pull in Soft Soil ................................................. 8 4.4 Amphibious Vehicle Tests (Drawbar Pull in Water and Bollard Pull

  15. Effect of solvent/polymer infiltration and irradiation on microstructure and tensile properties of carbon nanotube yarns

    DOE PAGES

    Hiremath, Nitilaksha; Lu, Xinyi; Evora, Maria Cecilia; ...

    2016-07-29

    Recently carbon nanotube (CNT) yarns have been gaining importance as an approach to harvest the excellent properties of the CNTs. However, the properties of CNT yarns at this stage are well below the expected value. Investigation of the structure of CNT yarns and possible approaches to enhance the strength and modulus are reported. Scanning electron microscopy and focused ion beam imaging reveal the inherently porous structure and poor orientation, emphasizing the need to enhance packing of CNT bundles in the yarns for increased strength and modulus. Densification of CNT yarn by toluene or polystyrene increases the strength by 140 ormore » 172 % and modulus by 79 or 218 %, respectively, as compared to that of the pristine yarn. E-beam irradiation was investigated as a means to introduce crosslinking and enhanced internanotubes bonding to increase strength and modulus. However, the irradiation resulted in generation of defects and damages to the yarn contributing to reduction in strength and modulus. Raman spectroscopy studies on the irradiated samples reveal the change in bonding characteristics resulting in poor mechanical properties. As a result, denser packing of nanotubes and increased interaction without any damage is the key to improve the properties of CNT yarns.« less

  16. Effect of solvent/polymer infiltration and irradiation on microstructure and tensile properties of carbon nanotube yarns

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

    Hiremath, Nitilaksha; Lu, Xinyi; Evora, Maria Cecilia

    Recently carbon nanotube (CNT) yarns have been gaining importance as an approach to harvest the excellent properties of the CNTs. However, the properties of CNT yarns at this stage are well below the expected value. Investigation of the structure of CNT yarns and possible approaches to enhance the strength and modulus are reported. Scanning electron microscopy and focused ion beam imaging reveal the inherently porous structure and poor orientation, emphasizing the need to enhance packing of CNT bundles in the yarns for increased strength and modulus. Densification of CNT yarn by toluene or polystyrene increases the strength by 140 ormore » 172 % and modulus by 79 or 218 %, respectively, as compared to that of the pristine yarn. E-beam irradiation was investigated as a means to introduce crosslinking and enhanced internanotubes bonding to increase strength and modulus. However, the irradiation resulted in generation of defects and damages to the yarn contributing to reduction in strength and modulus. Raman spectroscopy studies on the irradiated samples reveal the change in bonding characteristics resulting in poor mechanical properties. As a result, denser packing of nanotubes and increased interaction without any damage is the key to improve the properties of CNT yarns.« less

  17. Electro-spun PLA-PEG-yarns for tissue engineering applications.

    PubMed

    Kruse, Magnus; Greuel, Marc; Kreimendahl, Franziska; Schneiders, Thomas; Bauer, Benedict; Gries, Thomas; Jockenhoevel, Stefan

    2018-06-27

    Electro-spinning is widely used in tissue-engineered applications mostly in form of non-woven structures. The development of e-spun yarn opens the door for textile fabrics which combine the micro to nanoscale dimension of electro-spun filaments with three-dimensional (3D) drapable textile fabrics. Therefore, the aim of the study was the implementation of a process for electro-spun yarns. Polylactic acid (PLA) and polyethylene glycol (PEG) were spun from chloroform solutions with varying PLA/PEG ratios (100:0, 90:10, 75:25 and 50:50). The yarn samples produced were analyzed regarding their morphology, tensile strength, water uptake and cytocompatibility. It was found that the yarn diameter decreased when the funnel collector rotation was increasd, however, the fiber diameter was not influenced. The tensile strength was also found to be dependent on the PEG content. While samples composed of 100% PLA showed a tensile strength of 2.5±0.7 cN/tex, the tensile strength increased with a decreasing PLA content (PLA 75%/PEG 25%) to 6.2±0.5 cN/tex. The variation of the PEG content also influenced the viscosity of the spinning solutions. The investigation of the cytocompatibility with endothelial cells was conducted for PLA/PEG 90:10 and 75:25 and indicated that the samples are cytocompatible.

  18. The Effect of Plain-Weaving on the Mechanical Properties of Warp and Weft P-Phenylene Terephthalamide (PPTA) Fibers/Yarns

    DTIC Science & Technology

    2014-08-15

    made of hybrid polypropylene /glass yarns, at different testing strain rates. The results obtained relatively little damage (and, hence, strength...l 1.1 1.2 1.3 1.4 1.5 1.6 1.7 -20 0 20 40 60 80 (a) Two-Bond-Angle, rad B o n d -A n g le E n er g y, k J/ m o l 2.8 3 3.2 3.4 0 100 200 300 400 500...Experimental characterization of the tensile behavior of a polypropylene /glass 3D-fabric: from the yarn to the fabric. In: 4th world conference on 3D fabrics

  19. [Research progresses on ergonomics assessment and measurement methods for push-pull behavior].

    PubMed

    Zhao, Yan; Li, Dongxu; Guo, Shengpeng

    2011-10-01

    Pushing and pulling (P&P) is a common operating mode of operator's physical works, and plays an important role in evaluation of human behavior health and operation performance. At present, there are many research methods of P&P, and this article is a state-of-art review of the classification of P&P research methods, the various impact factors in P&P program, technical details of internal/external P&P force measurement and evaluation, the limitation of current research methods and the future developments in the ergonomics field.

  20. Nanofibrous Smart Fabrics from Twisted Yarns of Electrospun Piezopolymer.

    PubMed

    Yang, Enlong; Xu, Zhe; Chur, Lucas K; Behroozfar, Ali; Baniasadi, Mahmoud; Moreno, Salvador; Huang, Jiacheng; Gilligan, Jules; Minary-Jolandan, Majid

    2017-07-19

    Smart textiles are envisioned to make a paradigm shift in wearable technologies to directly impart functionality into the fibers rather than integrating sensors and electronics onto conformal substrates or skin in wearable devices. Among smart materials, piezoelectric fabrics have not been widely reported, yet. Piezoelectric smart fabrics can be used for mechanical energy harvesting, for thermal energy harvesting through the pyroelectric effect, for ferroelectric applications, as pressure and force sensors, for motion detection, and for ultrasonic sensing. We report on mechanical and material properties of the plied nanofibrous piezoelectric yarns as a function of postprocessing conditions including thermal annealing and drawing (stretching). In addition, we used a continuous electrospinning setup to directly produce P(VDF-TrFE) nanofibers and convert them into twisted plied yarns, and demonstrated application of these plied yarns in woven piezoelectric fabrics. The results of this work can be an early step toward realization of piezoelectric smart fabrics.

  1. An Evaluation of Two English Language Learner (ELL) Instructional Models at School District ABC: Pull-In and Push-Out

    ERIC Educational Resources Information Center

    Lloyd, Sonya LaShawn

    2014-01-01

    Providing academic assistance to English Language Learners (ELLs) is varied and often ineffective. The purpose of this causal-comparative study was to determine if there was a relationship between 9th grade students' performance on the High School Graduation Exam (HSGE) in reading and language and the Push-in and Pull-out models of instruction.…

  2. Developing an Acoustic Sensing Yarn for Health Surveillance in a Military Setting

    PubMed Central

    Dias, Tilak

    2018-01-01

    Overexposure to high levels of noise can cause permanent hearing disorders, which have a significant adverse effect on the quality of life of those affected. Injury due to noise can affect people in a variety of careers including construction workers, factory workers, and members of the armed forces. By monitoring the noise exposure of workers, overexposure can be avoided and suitable protective equipment can be provided. This work focused on the creation of a noise dosimeter suitable for use by members of the armed forces, where a discrete dosimeter was integrated into a textile helmet cover. In this way the sensing elements could be incorporated very close to the ears, providing a highly representative indication of the sound level entering the body, and also creating a device that would not interfere with military activities. This was achieved by utilising commercial microelectromechanical system microphones integrated within the fibres of yarn to create an acoustic sensing yarn. The acoustic sensing yarns were fully characterised over a range of relevant sound levels and frequencies at each stage in the yarn production process. The yarns were ultimately integrated into a knitted helmet cover to create a functional acoustic sensing helmet cover prototype. PMID:29772756

  3. Recent researches concerning the obtaining of functional textiles based on conductive yarns

    NASA Astrophysics Data System (ADS)

    Leon, A. L.; Manea, L. R.; Hristian, L.

    2016-08-01

    Modem textile industry is influenced both by consumers' lifestyle and by novel materials. Functional textiles can be included into the group of technical textiles. The functional activity can be shortly interpreted as "sense - react - adapt" to the environment while traditional materials meet only passive protective role, a barrier between body and environment. Functional materials cross the conventional limits because they are designed for specific performances, being part of domains as: telemedicine, medicine, aeronautics, biotechnology, nanotechnology, protective clothes, sportswear, etc. This paper highlights the most recent developments in the field of using conductive yarns for obtaining functional textiles. Conductive fabrics can be done by incorporating into the textile structure the conductive fibers / yarns. The technologies differ from embroidering, sewing, weaving, knitting to braiding and obtaining nonwovens. The conductive fabrics production has a quickly growth because it is a high demand for these textiles used for data transfer in clothing, monitoring vital signs, germ-free garments, brain-computer interface, etc. Nowadays it is of high interest surface treatments of fibers/yarns which can be considered as a novel kind of textile finishing. There are presented some researches related to obtaining conductive yarns by coating PET and PP yarns with PANi conductive polymer.

  4. Moisture Management Behaviour of Knitted Fabric from Structurally Modified Ring and Vortex Spun Yarn

    NASA Astrophysics Data System (ADS)

    Sharma, Navendu; Kumar, Pawan; Bhatia, Dinesh; Sinha, Sujit Kumar

    2016-10-01

    The acceptability of a new product is decided by its performance, level of improvement in quality and economy of production. The basic aim of generating micro pores in a textile structure is to provide better thermo-physiological comfort by enhancing the breathability and hence improving moisture management behaviour. In the present study, an attempt has been made to create a relatively more open structure through removal of a component. A comparative assessment with a homogeneous and parent yarn was also made. Yarns of two linear densities, each from ring and vortex spinning systems were produced using 100 % polyester and 80:20 polyester/cotton blend. The modified yarn was produced by removing a component, viz; cotton, by treatment with sulphuric acid from the blended yarn. The knitted fabric from modified yarn was found to show significant improvement in air permeability, water vapour permeability and total absorbency while the wicking characteristic was found to decline.

  5. Properties of CF/PA6 friction spun hybrid yarns for textile reinforced thermoplastic composites

    NASA Astrophysics Data System (ADS)

    Hasan, MMB; Nitsche, S.; Abdkader, A.; Cherif, Ch

    2017-10-01

    Due to their excellent strength, rigidity and damping properties as well as low weight, carbon fibre reinforced composites (CFRC) are widely being used for load bearing structures. On the other hand, with an increased demand und usage of CFRCs, effective methods to re-use waste carbon fibre (CF) materials, which are recoverable either from the process scraps or from the end-of-life components are attracting increased attention. In this paper, hybrid yarns consisting of staple CF and polyamide 6 (PA 6) are manufactured on a DREF-3000 friction spinning machine with various machine parameters such as spinning drum speed and suction air pressure. The relationship between different textile physical properties of the hybrid yarns, such as tensile strength and elongation with different spinning parameters and CF content of hybrid yarn is investigated. Furthermore, the tensile properties of uni-directional (UD) composites manufactured from the developed hybrid yarn shows 80% of the UD composite strength made from CF filament yarn.

  6. A Fast Response Ammonia Sensor Based on Coaxial PPy-PAN Nanofiber Yarn.

    PubMed

    Liu, Penghong; Wu, Shaohua; Zhang, Yue; Zhang, Hongnan; Qin, Xiaohong

    2016-06-23

    Highly orientated polypyrrole (PPy)-coated polyacrylonitrile (PAN) (PPy-PAN) nanofiber yarn was prepared with an electrospinning technique and in-situ chemical polymerization. The morphology and chemical structure of PPy-PAN nanofiber yarn was characterized by scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and fourier transform infrared spectroscopy (FTIR), which indicated that the PPy as the shell layer was homogeneously and uniformly polymerized on the surface of PAN nanofiber. The effects of different concentration of doping acid on the responses of PPy-PAN nanofiber yarn sensor were investigated. The electrical responses of the gas sensor based on the PPy-PAN nanofiber yarn to ammonia were investigated at room temperature. The nanoyarn sensor composed of uniaxially aligned PPy-PAN nanofibers with a one-dimensional structure exhibited a transient response, and the response time was less than 1 s. The excellent sensing properties mentioned above give rise to good potential application prospects in the field of ammonia sensor.

  7. Multiscale mechanics of the lateral pressure effect on enhancing the load transfer between polymer coated CNTs.

    PubMed

    Yazdandoost, Fatemeh; Mirzaeifar, Reza; Qin, Zhao; Buehler, Markus J

    2017-05-04

    While individual carbon nanotubes (CNTs) are known as one of the strongest fibers ever known, even the strongest fabricated macroscale CNT yarns and fibers are still significantly weaker than individual nanotubes. The loss in mechanical properties is mainly because the deformation mechanism of CNT fibers is highly governed by the weak shear strength corresponding to sliding of nanotubes on each other. Adding polymer coating to the bundles, and twisting the CNT yarns to enhance the intertube interactions are both efficient methods to improve the mechanical properties of macroscale yarns. Here, we perform molecular dynamics (MD) simulations to unravel the unknown deformation mechanism in the intertube polymer chains and also local deformations of the CNTs at the atomistic scale. Our results show that the lateral pressure can have both beneficial and adverse effects on shear strength of polymer coated CNTs, depending on the local deformations at the atomistic scale. In this paper we also introduce a bottom-up bridging strategy between a full atomistic model and a coarse-grained (CG) model. Our trained CG model is capable of incorporating the atomistic scale local deformations of each CNT to the larger scale collect behavior of bundles, which enables the model to accurately predict the effect of lateral pressure on larger CNT bundles and yarns. The developed multiscale CG model is implemented to study the effect of lateral pressure on the shear strength of straight polymer coated CNT yarns, and also the effect of twisting on the pull-out force of bundles in spun CNT yarns.

  8. A Complex Shaped Reinforced Thermoplastic Composite Part Made of Commingled Yarns With Integrated Sensor

    NASA Astrophysics Data System (ADS)

    Risicato, Jean-Vincent; Kelly, Fern; Soulat, Damien; Legrand, Xavier; Trümper, Wolfgang; Cochrane, Cedric; Koncar, Vladan

    2015-02-01

    This paper focuses on the design and one shot manufacturing process of complex shaped composite parts based on the overbraiding of commingled yarns. The commingled yarns contain thermoplastic fibres used as the matrix and glass fibres as the reinforcement material. This technology reduces the flow path length for the melted thermoplastic and aims to improve the impregnation of materials with high viscosity. The tensile strength behaviour of the material was firstly investigated in order to evaluate the influence of the manufacturing parameters on flat structured braids that have been consolidated on a heating press. A good compatibility between the required geometry and the braiding process was observed. Additionally, piezo-resistive sensor yarns, based on glass yarns coated with PEDOT: PSS, have been successfully integrated within the composite structure. The sensor yarns have been inserted into the braided fabric, before consolidation. The inserted sensors provide the ability to monitor the structural health of the composite part in a real time. The design and manufacture of the complete complex shaped part has then been successfully achieved.

  9. A display module implemented by the fast high-temperatue response of carbon nanotube thin yarns.

    PubMed

    Wei, Yang; Liu, Peng; Jiang, Kaili; Fan, Shoushan

    2012-05-09

    Suspending superaligned multiwalled carbon nanotube (MWCNT) films were processed into CNT thin yarns, about 1 μm in diameter, by laser cutting and an ethanol atomization bath treatment. The fast high-temperature response under a vacuum was revealed by monitoring the incandescent light with a photo diode. The thin yarns can be electrically heated up to 2170 K in 0.79 mS, and the succeeding cool-down time is 0.36 mS. The fast response is attributed to the ultrasmall mass of the independent single yarn, large radiation coefficient, and improved thermal conductance through the two cool ends. The millisecond response time makes it possible to use the visible hot thin yarns as light-emitting elements of an incandescent display. A fully sealed display with 16 × 16 matrix was successfully fabricated using screen-printed thick electrodes and CNT thin yarns. It can display rolling characters with a low power consumption. More applications can be further developed based on the addressable CNT thermal arrays.

  10. Piezoresistive effect of the carbon nanotube yarn embedded axially into the 3D braided composite

    NASA Astrophysics Data System (ADS)

    Ma, Xin; Cao, Xiaona

    2018-06-01

    A new method for monitoring 3D braided composite structure health in real time by embedding the carbon nanotube yarn, based on its piezoresistivity, in the composite axially has been designed. The experimental system for piezoresistive effect detection of the carbon nanotube yarn in the 3D braided composite was built, and the sensing characteristics has been analyzed for further research. Compared with other structural health monitoring methods, the monitoring technique with carbon nanotubes yarns is more suitable for internal damage detection immediately, in addition the strength of the composite can be increased by embedding carbon nanotubes yarns. This method can also be used for strain sensing, the development of intelligent materials and structure systems.

  11. From industrially weavable and knittable highly conductive yarns to large wearable energy storage textiles.

    PubMed

    Huang, Yan; Hu, Hong; Huang, Yang; Zhu, Minshen; Meng, Wenjun; Liu, Chang; Pei, Zengxia; Hao, Chonglei; Wang, Zuankai; Zhi, Chunyi

    2015-05-26

    Wearable electronic textiles that store capacitive energy are a next frontier in personalized electronics. However, the lack of industrially weavable and knittable conductive yarns in conjunction with high capacitance, limits the wide-scale application of such textiles. Here pristine soft conductive yarns are continuously produced by a scalable method with the use of twist-bundle-drawing technique, and are mechanically robust enough to be knitted to a cloth by a commercial cloth knitting machine. Subsequently, the reduced-graphene-oxide-modified conductive yarns covered with a hierarchical structure of MnO2 nanosheets and a polypyrrole thin film were used to fabricate weavable, knittable and wearable yarn supercapacitors. The resultant modified yarns exhibit specific capacitances as high as 36.6 mF cm(-1) and 486 mF cm(-2) in aqueous electrolyte (three-electrode cell) or 31 mF cm(-1) and 411 mF cm(-2) in all solid-state two-electrode cell. The symmetric solid-state supercapacitor has high energy densities of 0.0092 mWh cm(-2) and 1.1 mWh cm(-3) (both normalized to the whole device) with a long cycle life. Large energy storage textiles are fabricated by weaving our flexible all-solid-state supercapacitor yarns to a 15 cm × 10 cm cloth on a loom and knitting in a woollen wrist band to form a pattern, enabling dual functionalities of energy storage capability and wearability.

  12. Bioresorbable composite screws manufactured via forging process: pull-out, shear, flexural and degradation characteristics.

    PubMed

    Felfel, R M; Ahmed, I; Parsons, A J; Rudd, C D

    2013-02-01

    Bioresorbable screws have the potential to overcome some of the complications associated with metallic screws currently in use. Removal of metallic screws after bone has healed is a serious issue which can lead to refracture due to the presence of screw holes. Poly lactic acid (PLA), fully 40 mol% P(2)O(5) containing phosphate unidirectional (P40UD) and a mixture of UD and short chopped strand random fibre mats (P40 70%UD/30%RM) composite screws were prepared via forging composite bars. Water uptake and mass loss for the composite screws manufactured increased significantly to ∼1.25% (P=0.0002) and ∼1.1% (P<0.0001), respectively, after 42 days of immersion in PBS at 37 °C. The initial maximum flexural load for P40 UD/RM and P40 UD composite screws was ∼60% (P=0.0047) and ∼100% (P=0.0037) higher than for the PLA screws (∼190 N), whilst the shear load was slightly higher in comparison to PLA (∼2.2 kN). The initial pull-out strengths for the P40 UD/RM and PLA screws were similar whereas that for P40 UD screws was ∼75% higher (P=0.022). Mechanical properties for the composite screws decreased initially after 3 days of immersion and this reduction was ascribed to the degradation of the fibre/matrix interface. After 3 days interval the mechanical properties (flexural, shear and pull-out) maintained their integrity for the duration of the study (at 42 days). This property retention was attributed to the chemical durability of the fibres used and stability of the matrix properties during the degradation process. It was also deemed necessary to enhance the fibre/matrix interface via use of a coupling agent in order to maintain the initial mechanical properties acquired for the required period of time. Lastly, it is also suggested that the degrading reinforcement fibres may have the potential to buffer any acidic products released from the PLA matrix. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Deformation and Failure of a Multi-Wall Carbon Nanotube Yarn Composite

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.; Jefferson, Gail D.; Frankland, Sarah-Jane V.

    2008-01-01

    Forests of multi-walled carbon nanotubes can be twisted and manipulated into continuous fibers or yarns that exhibit many of the characteristics of traditional textiles. Macro-scale analysis and test may provide strength and stiffness predictions for a composite composed of a polymer matrix and low-volume fraction yarns. However, due to the nano-scale of the carbon nanotubes, it is desirable to use atomistic calculations to consider tube-tube interactions and the influence of simulated twist on the effective friction coefficient. This paper reports laboratory test data on the mechanical response of a multi-walled, carbon nanotube yarn/polymer composite from both dynamic and quasi-static tensile tests. Macroscale and nano-scale analysis methods are explored and used to define some of the key structure-property relationships. The measured influence of hot-wet aging on the tensile properties is also reported.

  14. Magnetoreresistance of carbon nanotube-polypyrrole composite yarns

    NASA Astrophysics Data System (ADS)

    Ghanbari, R.; Ghorbani, S. R.; Arabi, H.; Foroughi, J.

    2018-05-01

    Three types of samples, carbon nanotube yarn and carbon nanotube-polypyrrole composite yarns had been investigated by measurement of the electrical conductivity as a function of temperature and magnetic field. The conductivity was well explained by 3D Mott variable range hopping (VRH) law at T < 100 K. Both positive and negative magnetoresistance (MR) were observed by increasing magnetic field. The MR data were analyzed based a theoretical model. A quadratic positive and negative MR was observed for three samples. It was found that the localization length decreases with applied magnetic field while the density of states increases. The increasing of the density of states induces increasing the number of available energy states for hopping. Thus the electron hopping probability increases in between sites with the shorter distance that results to small the average hopping length.

  15. Micro-Scale Mechanical Testing of Non-Woven Carbon Nanotube Sheets and Yarns

    NASA Technical Reports Server (NTRS)

    Magargee, J.; Morestin, F.; Cao, J.; Jones, J. S.

    2013-01-01

    Non-woven carbon nanotube (CNT) sheets and yarns were tested using a novel micro-scale mechanical testing system. CNT sheets were observed to delaminate during uniaxial testing using an adbesive gripping method, resulting from a higher proportion of load bearing in the outer sheets versus internal sheets and an apparently low interlaminar shear strength. In response to this, a new spool-grip method was used to alleviate non-uniform through-thickness stresses, circumvent premature delamination, and allow the sheet material to sustain a 72% increase in measured tensile strength. Furthermore, tension tests of CNT yarns showed that the yarn-structure was approximaiely 7 times stronger than the sheet structure, owing to a higher degree of CNT alignment in the test direction.

  16. Cost-Benefit and Performance of Handmade Carpets Produced with Wool, Untreated and Chemical Treated Jute Pile Yarns

    NASA Astrophysics Data System (ADS)

    Gupta, Shravan Kumar; Goswami, Kamal Kanti

    2018-03-01

    Jute is a natural fibre which is used to make different type of products due to low cost, easy availability and eco-friendliness. However, the stiffness and harshness of jute fibre affect the use of jute in many products like pile yarns in hand knotted carpets. In this research, a study has been done on the application of jute pile yarns in Persian hand knotted carpet. Three types of commercial yarns (wool, untreated jute and woollenized jute) as well as three types of chemical treated jute yarns (hydrogen peroxide bleached, softened bleached and woollenized yarns) have been applied as pile yarns in Persian hand knotted carpets. Cost-benefit analysis of hand knotted carpets shows that manufacturing cost of wool carpet is lower than others. The contribution of manpower charges is higher than material cost during carpet manufacturing. Hand knotted carpet shows the lowest pile abrasion loss and highest compression recovery when wool is used as pile. Wool hand knotted carpet shows higher compression than untreated and treated jute carpets.

  17. Cost-Benefit and Performance of Handmade Carpets Produced with Wool, Untreated and Chemical Treated Jute Pile Yarns

    NASA Astrophysics Data System (ADS)

    Gupta, Shravan Kumar; Goswami, Kamal Kanti

    2018-06-01

    Jute is a natural fibre which is used to make different type of products due to low cost, easy availability and eco-friendliness. However, the stiffness and harshness of jute fibre affect the use of jute in many products like pile yarns in hand knotted carpets. In this research, a study has been done on the application of jute pile yarns in Persian hand knotted carpet. Three types of commercial yarns (wool, untreated jute and woollenized jute) as well as three types of chemical treated jute yarns (hydrogen peroxide bleached, softened bleached and woollenized yarns) have been applied as pile yarns in Persian hand knotted carpets. Cost-benefit analysis of hand knotted carpets shows that manufacturing cost of wool carpet is lower than others. The contribution of manpower charges is higher than material cost during carpet manufacturing. Hand knotted carpet shows the lowest pile abrasion loss and highest compression recovery when wool is used as pile. Wool hand knotted carpet shows higher compression than untreated and treated jute carpets.

  18. Wearable energy-dense and power-dense supercapacitor yarns enabled by scalable graphene–metallic textile composite electrodes

    PubMed Central

    Liu, Libin; Yu, You; Yan, Casey; Li, Kan; Zheng, Zijian

    2015-01-01

    One-dimensional flexible supercapacitor yarns are of considerable interest for future wearable electronics. The bottleneck in this field is how to develop devices of high energy and power density, by using economically viable materials and scalable fabrication technologies. Here we report a hierarchical graphene–metallic textile composite electrode concept to address this challenge. The hierarchical composite electrodes consist of low-cost graphene sheets immobilized on the surface of Ni-coated cotton yarns, which are fabricated by highly scalable electroless deposition of Ni and electrochemical deposition of graphene on commercial cotton yarns. Remarkably, the volumetric energy density and power density of the all solid-state supercapacitor yarn made of one pair of these composite electrodes are 6.1 mWh cm−3 and 1,400 mW cm−3, respectively. In addition, this SC yarn is lightweight, highly flexible, strong, durable in life cycle and bending fatigue tests, and integratable into various wearable electronic devices. PMID:26068809

  19. Wearable energy-dense and power-dense supercapacitor yarns enabled by scalable graphene-metallic textile composite electrodes.

    PubMed

    Liu, Libin; Yu, You; Yan, Casey; Li, Kan; Zheng, Zijian

    2015-06-11

    One-dimensional flexible supercapacitor yarns are of considerable interest for future wearable electronics. The bottleneck in this field is how to develop devices of high energy and power density, by using economically viable materials and scalable fabrication technologies. Here we report a hierarchical graphene-metallic textile composite electrode concept to address this challenge. The hierarchical composite electrodes consist of low-cost graphene sheets immobilized on the surface of Ni-coated cotton yarns, which are fabricated by highly scalable electroless deposition of Ni and electrochemical deposition of graphene on commercial cotton yarns. Remarkably, the volumetric energy density and power density of the all solid-state supercapacitor yarn made of one pair of these composite electrodes are 6.1 mWh cm(-3) and 1,400 mW cm(-3), respectively. In addition, this SC yarn is lightweight, highly flexible, strong, durable in life cycle and bending fatigue tests, and integratable into various wearable electronic devices.

  20. High-Cycle, Push-Pull Fatigue Fracture Behavior of High-C, Si-Al-Rich Nanostructured Bainite Steel.

    PubMed

    Zhao, Jing; Ji, Honghong; Wang, Tiansheng

    2017-12-29

    The high-cycle, push-pull fatigue fracture behavior of high-C, Si-Al-rich nanostructured bainitic steel was studied through the measurement of fatigue limits, a morphology examination and phase composition analysis of the fatigue fracture surface, as well as fractography of the fatigue crack propagation. The results demonstrated that the push-pull fatigue limits at 10⁷ cycles were estimated as 710-889 MPa, for the samples isothermally transformed at the temperature range of 220-260 °C through data extrapolation, measured under the maximum cycle number of 10⁵. Both the interior inclusion and the sample surface constituted the fatigue crack origins. During the fatigue crack propagation, a high amount of secondary cracks were formed in almost parallel arrangements. The apparent plastic deformation occurred in the fracture surface layer, which induced approximately all retained austenite to transform into martensite.

  1. High-Cycle, Push–Pull Fatigue Fracture Behavior of High-C, Si–Al-Rich Nanostructured Bainite Steel

    PubMed Central

    Zhao, Jing; Ji, Honghong

    2017-01-01

    The high-cycle, push–pull fatigue fracture behavior of high-C, Si–Al-rich nanostructured bainitic steel was studied through the measurement of fatigue limits, a morphology examination and phase composition analysis of the fatigue fracture surface, as well as fractography of the fatigue crack propagation. The results demonstrated that the push–pull fatigue limits at 107 cycles were estimated as 710–889 MPa, for the samples isothermally transformed at the temperature range of 220–260 °C through data extrapolation, measured under the maximum cycle number of 105. Both the interior inclusion and the sample surface constituted the fatigue crack origins. During the fatigue crack propagation, a high amount of secondary cracks were formed in almost parallel arrangements. The apparent plastic deformation occurred in the fracture surface layer, which induced approximately all retained austenite to transform into martensite. PMID:29286325

  2. Nonlinear dynamic behaviors of permanent magnet synchronous motors in electric vehicles caused by unbalanced magnetic pull

    NASA Astrophysics Data System (ADS)

    Xiang, Changle; Liu, Feng; Liu, Hui; Han, Lijin; Zhang, Xun

    2016-06-01

    Unbalanced magnetic pull (UMP) plays a key role in nonlinear dynamic behaviors of permanent magnet synchronous motors (PMSM) in electric vehicles. Based on Jeffcott rotor model, the stiffness characteristics of the rotor system of the PMSM are analyzed and the nonlinear dynamic behaviors influenced by UMP are investigated. In free vibration study, eigenvalue-based stability analysis for multiple equilibrium points is performed which offers an insight in system stiffness. Amplitude modulation effects are discovered of which the mechanism is explained and the period of modulating signal is carried out by phase analysis and averaging method. The analysis indicates that the effects are caused by the interaction of the initial phases of forward and backward whirling motions. In forced vibration study, considering dynamic eccentricity, frequency characteristics revealing softening type are obtained by harmonic balance method, and the stability of periodic solution is investigated by Routh-Hurwitz criterion. The frequency characteristics analysis indicates that the response amplitude is limited in the range between the amplitudes of the two kinds of equilibrium points. In the vicinity of the continuum of equilibrium points, the system hardly provides resistance to bending, and hence external disturbances easily cause loss of stability. It is useful for the design of the PMSM with high stability and low vibration and acoustic noise.

  3. Direct Lentiviral-Cyclooxygenase 2 Application to the Tendon-Bone Interface Promotes Osteointegration and Enhances Return of the Pull-Out Tensile Strength of the Tendon Graft in a Rat Model of Biceps Tenodesis

    PubMed Central

    Wergedal, Jon E.; Stiffel, Virginia; Lau, Kin-Hing William

    2014-01-01

    This study sought to determine if direct application of the lentiviral (LV)-cyclooxygenase 2 (COX2) vector to the tendon-bone interface would promote osteointegration of the tendon graft in a rat model of biceps tenodesis. The LV-COX2 gene transfer strategy was chosen for investigation because a similar COX2 gene transfer strategy promoted bony bridging of the fracture gap during bone repair, which involves similar histologic transitions that occur in osteointegration. Briefly, a 1.14-mm diameter tunnel was drilled in the mid-groove of the humerus of adult Fischer 344 rats. The LV-COX2 or βgal control vector was applied directly into the bone tunnel and onto the end of the tendon graft, which was then pulled into the bone tunnel. A poly-L-lactide pin was press-fitted into the tunnel as interference fixation. Animals were sacrificed at 3, 5, or 8 weeks for histology analysis of osteointegration. The LV-COX2 gene transfer strategy enhanced neo-chondrogenesis at the tendon-bone interface but with only marginal effect on de novo bone formation. The tendon-bone interface of the LV-COX2-treated tenodesis showed the well-defined tendon-to-fibrocartilage-to-bone histologic transitions that are indicative of osteointegration of the tendon graft. The LV-COX2 in vivo gene transfer strategy also significantly enhanced angiogenesis at the tendon-bone interface. To determine if the increased osteointegration was translated into an improved pull-out mechanical strength property, the pull-out tensile strength of the LV-COX2-treated tendon grafts was determined with a pull-out mechanical testing assay. The LV-COX2 strategy yielded a significant improvement in the return of the pull-out strength of the tendon graft after 8 weeks. In conclusion, the COX2-based in vivo gene transfer strategy enhanced angiogenesis, osteointegration and improved return of the pull-out strength of the tendon graft. Thus, this strategy has great potential to be developed into an effective therapy to

  4. Multifunctional smart composites with integrated carbon nanotube yarn and sheet

    NASA Astrophysics Data System (ADS)

    Chauhan, Devika; Hou, Guangfeng; Ng, Vianessa; Chaudhary, Sumeet; Paine, Michael; Moinuddin, Khwaja; Rabiee, Massoud; Cahay, Marc; Lalley, Nicholas; Shanov, Vesselin; Mast, David; Liu, Yijun; Yin, Zhangzhang; Song, Yi; Schulz, Mark

    2017-04-01

    Multifunctional smart composites (MSCs) are materials that combine the good electrical and thermal conductivity, high tensile and shear strength, good impact toughness, and high stiffness properties of metals; the light weight and corrosion resistance properties of composites; and the sensing or actuation properties of smart materials. The basic concept for MSCs was first conceived by Daniel Inman and others about 25 years ago. Current laminated carbon and glass fiber polymeric composite materials have high tensile strength and are light in weight, but they still lack good electrical and thermal conductivity, and they are sensitive to delamination. Carbon nanotube yarn and sheets are lightweight, electrically and thermally conductive materials that can be integrated into laminated composite materials to form MSCs. This paper describes the manufacturing of high quality carbon nanotube yarn and sheet used to form MSCs, and integrating the nanotube yarn and sheet into composites at low volume fractions. Various up and coming technical applications of MSCs are discussed including composite toughening for impact and delamination resistance; structural health monitoring; and structural power conduction. The global carbon nanotube overall market size is estimated to grow from 2 Billion in 2015 to 5 Billion by 2020 at a CAGR of 20%. Nanotube yarn and sheet products are predicted to be used in aircraft, wind machines, automobiles, electric machines, textiles, acoustic attenuators, light absorption, electrical wire, sporting equipment, tires, athletic apparel, thermoelectric devices, biomedical devices, lightweight transformers, and electromagnets. In the future, due to the high maximum current density of nanotube conductors, nanotube electromagnetic devices may also become competitive with traditional smart materials in terms of power density.

  5. Yarn-dyed fabric defect classification based on convolutional neural network

    NASA Astrophysics Data System (ADS)

    Jing, Junfeng; Dong, Amei; Li, Pengfei; Zhang, Kaibing

    2017-09-01

    Considering that manual inspection of the yarn-dyed fabric can be time consuming and inefficient, we propose a yarn-dyed fabric defect classification method by using a convolutional neural network (CNN) based on a modified AlexNet. CNN shows powerful ability in performing feature extraction and fusion by simulating the learning mechanism of human brain. The local response normalization layers in AlexNet are replaced by the batch normalization layers, which can enhance both the computational efficiency and classification accuracy. In the training process of the network, the characteristics of the defect are extracted step by step and the essential features of the image can be obtained from the fusion of the edge details with several convolution operations. Then the max-pooling layers, the dropout layers, and the fully connected layers are employed in the classification model to reduce the computation cost and extract more precise features of the defective fabric. Finally, the results of the defect classification are predicted by the softmax function. The experimental results show promising performance with an acceptable average classification rate and strong robustness on yarn-dyed fabric defect classification.

  6. Pulled Motzkin paths

    NASA Astrophysics Data System (ADS)

    Janse van Rensburg, E. J.

    2010-08-01

    In this paper the models of pulled Dyck paths in Janse van Rensburg (2010 J. Phys. A: Math. Theor. 43 215001) are generalized to pulled Motzkin path models. The generating functions of pulled Motzkin paths are determined in terms of series over trinomial coefficients and the elastic response of a Motzkin path pulled at its endpoint (see Orlandini and Whittington (2004 J. Phys. A: Math. Gen. 37 5305-14)) is shown to be R(f) = 0 for forces pushing the endpoint toward the adsorbing line and R(f) = f(1 + 2cosh f))/(2sinh f) → f as f → ∞, for forces pulling the path away from the X-axis. In addition, the elastic response of a Motzkin path pulled at its midpoint is shown to be R(f) = 0 for forces pushing the midpoint toward the adsorbing line and R(f) = f(1 + 2cosh (f/2))/sinh (f/2) → 2f as f → ∞, for forces pulling the path away from the X-axis. Formal combinatorial identities arising from pulled Motzkin path models are also presented. These identities are the generalization of combinatorial identities obtained in directed paths models to their natural trinomial counterparts.

  7. Multi-layered sensor yarns for in situ monitoring of textile reinforced composites

    NASA Astrophysics Data System (ADS)

    Haentzsche, E.; Onggar, T.; Nocke, A.; Hund, R. D.; Cherif, Ch

    2017-10-01

    In this contribution, the characteristic of yarns that have intrinsically conductivity as well as such with coaxial conductive coatings acting as in situ strain sensors are described. The objective of the based research projects is the real-time in situ sensing of both global stresses acting on fibre reinforced plastic (FRP) components and the detection of resulted local microscopic damages due to creep, delamination and micro-cracks in the fibre-matrix interphase of glass fibre (GFRP) and carbon fibre (CFRP) composites. Sensor materials similar to the particular FRP and its mechanical behaviour have been chosen. In the first approach, GF- and aramid-based sensor yarns have been developed with multiple tailored silver layer coating system capable to distinguish multiple scaled damage mechanism due to these effects globally and locally. The second approach bases on the piezoresistive effect of CF rovings for their usage as in situ strain sensors. In the next step, suitable fibre and polymer film-based cleading have been tested and evaluated, granting sufficient electrical isolation to avoid shortcircuits between the conductive sensor layers itself or between the sensor and intrinsically conductive CFRP respectively. Initially, the sensor performance of global strain measurement, means the accumulated strain along the integration length of the sensor yarn, has been evaluated during tensile stressing of FRP with integrated suchlike functionalised sensor yarns.

  8. Electron Beam Irradiated Intercalated CNT Yarns For Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Waters, Deborah L.; Gaier, James R.; Williams, Tiffany S.; Lopez Calero, Johnny E.; Ramirez, Christopher; Meador, Michael A.

    2015-01-01

    Multi-walled CNT yarns have been experimentally and commercially created to yield lightweight, high conductivity fibers with good tensile properties for application as electrical wiring and multifunctional tendons. Multifunctional tendons are needed as the cable structures in tensegrity robots for use in planetary exploration. These lightweight robust tendons can provide mechanical strength for movement of the robot in addition to power distribution and data transmission. In aerospace vehicles, such as Orion, electrical wiring and harnessing mass can approach half of the avionics mass. Use of CNT yarns as electrical power and data cables could reduce mass of the wiring by thirty to seventy percent. These fibers have been intercalated with mixed halogens to increase their specific electrical conductivity to that near copper. This conductivity, combined with the superior strength and fatigue resistance makes it an attractive alternative to copper for wiring and multifunctional tendon applications. Electron beam irradiation has been shown to increase mechanical strength in pristine CNT fibers through increased cross-linking. Both pristine and intercalated CNT yarns have been irradiated using a 5-megavolt electron beam for various durations and the conductivities and tensile properties will be discussed. Structural information obtained using a field emission scanning electron microscope, energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy will correlate microstructural details with bulk properties.

  9. Multiscale modeling of interwoven Kevlar fibers based on random walk to predict yarn structural response

    NASA Astrophysics Data System (ADS)

    Recchia, Stephen

    Kevlar is the most common high-end plastic filament yarn used in body armor, tire reinforcement, and wear resistant applications. Kevlar is a trade name for an aramid fiber. These are fibers in which the chain molecules are highly oriented along the fiber axis, so the strength of the chemical bond can be exploited. The bulk material is extruded into filaments that are bound together into yarn, which may be chorded with other materials as in car tires, woven into a fabric, or layered in an epoxy to make composite panels. The high tensile strength to low weight ratio makes this material ideal for designs that decrease weight and inertia, such as automobile tires, body panels, and body armor. For designs that use Kevlar, increasing the strength, or tenacity, to weight ratio would improve performance or reduce cost of all products that are based on this material. This thesis computationally and experimentally investigates the tenacity and stiffness of Kevlar yarns with varying twist ratios. The test boundary conditions were replicated with a geometrically accurate finite element model, resulting in a customized code that can reproduce tortuous filaments in a yarn was developed. The solid model geometry capturing filament tortuosity was implemented through a random walk method of axial geometry creation. A finite element analysis successfully recreated the yarn strength and stiffness dependency observed during the tests. The physics applied in the finite element model was reproduced in an analytical equation that was able to predict the failure strength and strain dependency of twist ratio. The analytical solution can be employed to optimize yarn design for high strength applications.

  10. Thermoacoustic chips with carbon nanotube thin yarn arrays.

    PubMed

    Wei, Yang; Lin, Xiaoyang; Jiang, Kaili; Liu, Peng; Li, Qunqing; Fan, Shoushan

    2013-10-09

    Aligned carbon nanotube (CNT) films drawn from CNT arrays have shown the potential as thermoacoustic loudspeakers. CNT thermoacoustic chips with robust structures are proposed to promote the applications. The silicon-based chips can play sound and fascinating rhythms by feeding alternating currents and audio signal to the suspending CNT thin yarn arrays across grooves in them. In additional to the thin yarns, experiments further revealed more essential elements of the chips, the groove depth and the interdigital electrodes. The sound pressure depends on the depth of the grooves, and the thermal wavelength can be introduced to define the influence-free depth. The interdigital fingers can effectively reduce the driving voltage, making the chips safe and easy to use. The chips were successfully assembled into earphones and have been working stably for about one year. The thermoacoustic chips can find many applications in consumer electronics and possibly improve the audiovisual experience.

  11. Tensile strength of ramie yarn (spinning by machine)/HDPE thermoplastic matrix composites

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

    Banowati, Lies, E-mail: liesbano@gmail.com; Hadi, Bambang K., E-mail: bkhadi@ae.itb.ac.id; Suratman, Rochim, E-mail: rochim@material.itb.ac.id

    2016-03-29

    Technological developments should be trooped to prevent a gap between technology and environmental sustainability, then it needs to be developed “Green technology”. In this research is making of green composites which use natural fiber ramie as reinforcement. Whereas the matrix used was HDPE (High Density Polyethylene) thermoplastic polymer which could be recycled and had a good formability and flexibility. The ramie yarns and fibers for unidirectional (0°) direction respectively were mixed with HDPE powder and processed using hot compression molding. The surface morphology was observed by SEM (Scanning Electrone Microscopy). Results showed that both tensile strength of the ramie fiber/HDPEmore » composites increased in comparison with the ramie yarn (spinning by machine)/HDPE composites. However, the ramie yarn (spinning by machine)/HDPE composites have a good producibility for wider application. Analysis of the test results using the Weibull distribution as approaches to modeling the reliability of the specimens.« less

  12. Increased Tensile Strength of Carbon Nanotube Yarns and Sheets through Chemical Modification and Electron Beam Irradiation

    NASA Technical Reports Server (NTRS)

    Miller, Sandi G.; Williams, Tiffany S.; Baker, James S.; Sola, Francisco; Lebron-Colon, Marisabel; McCorkle, Linda S.; Wilmoth, Nathan G.; Gaier, James; Chen, Michelle; Meador, Michael A.

    2014-01-01

    The inherent strength of individual carbon nanotubes offers considerable opportunity for the development of advanced, lightweight composite structures. Recent work in the fabrication and application of carbon nanotube (CNT) forms such as yarns and sheets has addressed early nanocomposite limitations with respect to nanotube dispersion and loading; and has pushed the technology toward structural composite applications. However, the high tensile strength of an individual CNT has not directly translated to macro-scale CNT forms where bulk material strength is limited by inter-tube electrostatic attraction and slippage. The focus of this work was to assess post processing of CNT sheet and yarn to improve the macro-scale strength of these material forms. Both small molecule functionalization and e-beam irradiation was evaluated as a means to enhance tensile strength and Youngs modulus of the bulk CNT material. Mechanical testing results revealed a tensile strength increase in CNT sheets by 57 when functionalized, while an additional 48 increase in tensile strength was observed when functionalized sheets were irradiated; compared to unfunctionalized sheets. Similarly, small molecule functionalization increased yarn tensile strength up to 25, whereas irradiation of the functionalized yarns pushed the tensile strength to 88 beyond that of the baseline yarn.

  13. Effect of laser heat treatment on Pull-out bond strength of fiber posts treated with different silanes.

    PubMed

    Shafiei, Fereshteh; Saadat, Maryam; Jowkar, Zahra

    2018-05-01

    This study evaluated the effect of three different silanes and post-silanization treatments on the retentive strength of fiber posts luted with an etch-and-rinse resin cement. One hundred intact maxillary central incisors were randomly divided into 10 groups after endodontic treatment and post space preparation (n=10). The fiber posts were etched using 24% hydrogen peroxide. Posts of the control group did not receive silane. In nine experimental groups, each of the three silanes used, Scotchbond Universal adhesive, Bis-Silane and Porcelain Primer, was subjected to three treatments: air-drying at 25°C, warm air-drying and CO2 laser heat treatment. After cementation of the treated posts using One-Step Plus/Duo-Link cement, the specimens were stored for one weak and then subjected to pull-out bond strength (PBS) testing. The data in Newton (N) were analyzed using two-way ANOVA and Tukey tests (α=0.05). PBS was significantly affected by silane type and post-silanization treatment ( p <0.001). The interaction of the two factors was not statistically significant ( p =0.15). The effect of Porcelain Primer on PBS was significantly higher than those of universal adhesive ( p <0.001) and Bis-Silane ( p =0.01), with similar results for the two latter. Warm air-drying and laser treatment significantly increased PBS ( p <0.001). The lowest and highest PBS was obtained in the control (no silane) group (190.9±31) and laser-treated/ Porcelain Primer group (377.1±50), respectively. Warm air-drying and CO2 laser heat treatment had a significantly beneficial effect on retentive strength of fiber posts. Porcelain Primer was significantly more effective than universal adhesive and Bis-Silane. Key words: Laser heat treatment, Pull-out bond strength, fiber post.

  14. Pyrolytic boron nitride coatings on ceramic yarns and fabrication of insulations

    NASA Technical Reports Server (NTRS)

    Moore, Arthur W.

    1992-01-01

    Pyrolytic boron nitride (PBN) was deposited on Nicalon NL 202 silicon carbide yarns at 1000 to 1200 C with the goal of improving the resistance of the Nicalon to deterioration in an aerodynamic environment at temperatures up to 1000 C. For continuous coating, the yarns were fed through the deposition chamber of a pilot plant sized CVD furnace at a rate of about 2 feet per minute. PBN coatings were obtained by reacting boron trichloride and ammonia gases inside the deposition chamber. Most of the PBN coatings were made at around 1080 C to minimize thermal degradation of the Nicalon. Pressures were typically below 0.1 Torr. The coated yarns were characterized by weight per unit length, tensile strength and modulus, scanning electron microscopy, and scanning Auger microscopy. The PBN coated Nicalon was woven into cloth, but was not entirely satisfactory as a high temperature sizing. Several 13 in. square pieces of Nicalon cloth were coated with PBN in a batch process in a factory sized deposition furnace. Samples of cloth made from the PBN coated Nicalon were sewn into thermal insulation panels, whose performance is being compared with that of panels made using uncoated Nicalon.

  15. The Phenomenology of Hair Pulling Urges in Trichotillomania: A Comparative Approach

    PubMed Central

    Madjar, Shai; Sripada, Chandra S.

    2016-01-01

    Trichotillomania is a disorder characterized by recurrent urges to pull out one's hair, but the experiential characteristics of hair pulling urges are poorly understood. This study used a comparative approach to understand the subjective phenomenology of hair pulling: participants with trichotillomania symptoms were asked about their hair pulling urges as well as their urges to eat unhealthy foods. Participants who reported experiencing problematic unhealthy food urges were identified and asked to compare the phenomenological characteristics of their hair pulling and unhealthy food urges across a variety of dimensions. Results revealed significant differences for only some urge properties measured, and differences that existed were small to moderate in magnitude. Qualitative comparisons of the two urges revealed situational characteristics of hair pulling that could explain these small to moderate differences between the two urges. We conclude that hair pulling urges may be more comparable to ordinary urges such as unhealthy food urges than one might expect, but that hair pulling urges may nevertheless be rated as slightly more severe due to situational characteristics of these urges. This conception may improve clinician and lay understanding of the condition, assist with destigmatization efforts, and facilitate the development of treatment strategies. PMID:26925017

  16. New-type planar field emission display with superaligned carbon nanotube yarn emitter.

    PubMed

    Liu, Peng; Wei, Yang; Liu, Kai; Liu, Liang; Jiang, Kaili; Fan, Shoushan

    2012-05-09

    With the superaligned carbon nanotube yarn as emitter, we have fabricated a 16 × 16 pixel field emission display prototype by adopting screen printing and laser cutting technologies. A planar diode field emission structure has been adopted. A very sharp carbon nanotube yarn tip emitter can be formed by laser cutting. Low voltage phosphor was coated on the anode electrodes also by screen printing. With a specially designed circuit, we have demonstrated the dynamic character display with the field emission display prototype. The emitter material and fabrication technologies in this paper are both easy to scale up to large areas.

  17. INITIAL ASSESSMENT OF EMISSIONS FROM HEAT SETTING CARPET YARN

    EPA Science Inventory

    The report gives initial results of a project to determine the nature of emissions resulting from the heat setting of carpet yarn and to identify possible control options. o collect the necessary technical information, two manufacturing facilities were visited: World Carpets in D...

  18. INITIAL ASSESSMENT OF EMISSIONS FROM HEAT SETTING CARPET YARN

    EPA Science Inventory

    The report gives initial results of a project to determine the nature of emissions resulting from the heat setting of carpet yarn and to identify possible control options. To collect the necessary technical information, two manufacturing facilities were visited: World Carpets in ...

  19. Gliding flight: speed and acceleration of ideal falcons during diving and pull out.

    PubMed

    Tucker

    1998-01-14

    Some falcons, such as peregrines (Falco peregrinus), attack their prey in the air at the end of high-speed dives and are thought to be the fastest of animals. Estimates of their top speed in a dive range up to 157 m s-1, although speeds this high have never been accurately measured. This study investigates the aerodynamic and gravitational forces on 'ideal falcons' and uses a mathematical model to calculate speed and acceleration during diving. Ideal falcons have body masses of 0.5-2.0 kg and morphological and aerodynamic properties based on those measured for real falcons. The top speeds reached during a dive depend on the mass of the bird and the angle and duration of the dive. Given enough time, ideal falcons can reach top speeds of 89-112 m s-1 in a vertical dive, the higher speed for the heaviest bird, when the parasite drag coefficient has a value of 0.18. This value was measured for low-speed flight, and it could plausibly decline to 0.07 at high speeds. Top speeds then would be 138-174 m s-1. An ideal falcon diving at angles between 15 and 90 degrees with a mass of 1 kg reaches 95 % of top speed after travelling approximately 1200 m. The time and altitude loss to reach 95 % of top speed range from 38 s and 322 m at 15 degrees to 16 s and 1140 m at 90 degrees, respectively. During pull out at top speed from a vertical dive, the 1 kg ideal falcon can generate a lift force 18 times its own weight by reducing its wing span, compared with a lift force of 1.7 times its weight at full wing span. The falcon loses 60 m of altitude while pulling out of the dive, and lift and loss of altitude both decrease as the angle of the dive decreases. The 1 kg falcon can slow down in a dive by increasing its parasite drag and the angle of attack of its wings. Both lift and drag increase with angle of attack, but the falcon can cancel the increased lift by holding its wings in a cupped position so that part of the lift is directed laterally. The increased drag of wings producing

  20. High-performance multifunctional graphene yarns: toward wearable all-carbon energy storage textiles.

    PubMed

    Aboutalebi, Seyed Hamed; Jalili, Rouhollah; Esrafilzadeh, Dorna; Salari, Maryam; Gholamvand, Zahra; Aminorroaya Yamini, Sima; Konstantinov, Konstantin; Shepherd, Roderick L; Chen, Jun; Moulton, Simon E; Innis, Peter Charles; Minett, Andrew I; Razal, Joselito M; Wallace, Gordon G

    2014-03-25

    The successful commercialization of smart wearable garments is hindered by the lack of fully integrated carbon-based energy storage devices into smart wearables. Since electrodes are the active components that determine the performance of energy storage systems, it is important to rationally design and engineer hierarchical architectures atboth the nano- and macroscale that can enjoy all of the necessary requirements for a perfect electrode. Here we demonstrate a large-scale flexible fabrication of highly porous high-performance multifunctional graphene oxide (GO) and rGO fibers and yarns by taking advantage of the intrinsic soft self-assembly behavior of ultralarge graphene oxide liquid crystalline dispersions. The produced yarns, which are the only practical form of these architectures for real-life device applications, were found to be mechanically robust (Young's modulus in excess of 29 GPa) and exhibited high native electrical conductivity (2508 ± 632 S m(-1)) and exceptionally high specific surface area (2605 m(2) g(-1) before reduction and 2210 m(2) g(-1) after reduction). Furthermore, the highly porous nature of these architectures enabled us to translate the superior electrochemical properties of individual graphene sheets into practical everyday use devices with complex geometrical architectures. The as-prepared final architectures exhibited an open network structure with a continuous ion transport network, resulting in unrivaled charge storage capacity (409 F g(-1) at 1 A g(-1)) and rate capability (56 F g(-1) at 100 A g(-1)) while maintaining their strong flexible nature.

  1. Pull rod assembly

    DOEpatents

    Cioletti, O.C.

    1988-04-21

    A pull rod assembly comprising a pull rod having three peripheral grooves, a piston device including an adaptor ring and a seal ring, said piston device being mounted on the pull rod by a split ring retainer situated in one groove and extending into an interior groove in the adaptor and a resilient split ring retained in another groove and positioned to engage the piston device and to retain the seal on its adaptor.

  2. Electrically, chemically, and photonically powered torsional and tensile actuation of hybrid carbon nanotube yarn muscles.

    PubMed

    Lima, Márcio D; Li, Na; Jung de Andrade, Mônica; Fang, Shaoli; Oh, Jiyoung; Spinks, Geoffrey M; Kozlov, Mikhail E; Haines, Carter S; Suh, Dongseok; Foroughi, Javad; Kim, Seon Jeong; Chen, Yongsheng; Ware, Taylor; Shin, Min Kyoon; Machado, Leonardo D; Fonseca, Alexandre F; Madden, John D W; Voit, Walter E; Galvão, Douglas S; Baughman, Ray H

    2012-11-16

    Artificial muscles are of practical interest, but few types have been commercially exploited. Typical problems include slow response, low strain and force generation, short cycle life, use of electrolytes, and low energy efficiency. We have designed guest-filled, twist-spun carbon nanotube yarns as electrolyte-free muscles that provide fast, high-force, large-stroke torsional and tensile actuation. More than a million torsional and tensile actuation cycles are demonstrated, wherein a muscle spins a rotor at an average 11,500 revolutions/minute or delivers 3% tensile contraction at 1200 cycles/minute. Electrical, chemical, or photonic excitation of hybrid yarns changes guest dimensions and generates torsional rotation and contraction of the yarn host. Demonstrations include torsional motors, contractile muscles, and sensors that capture the energy of the sensing process to mechanically actuate.

  3. Electrically, Chemically, and Photonically Powered Torsional and Tensile Actuation of Hybrid Carbon Nanotube Yarn Muscles

    NASA Astrophysics Data System (ADS)

    Lima, Márcio D.; Li, Na; Jung de Andrade, Mônica; Fang, Shaoli; Oh, Jiyoung; Spinks, Geoffrey M.; Kozlov, Mikhail E.; Haines, Carter S.; Suh, Dongseok; Foroughi, Javad; Kim, Seon Jeong; Chen, Yongsheng; Ware, Taylor; Shin, Min Kyoon; Machado, Leonardo D.; Fonseca, Alexandre F.; Madden, John D. W.; Voit, Walter E.; Galvão, Douglas S.; Baughman, Ray H.

    2012-11-01

    Artificial muscles are of practical interest, but few types have been commercially exploited. Typical problems include slow response, low strain and force generation, short cycle life, use of electrolytes, and low energy efficiency. We have designed guest-filled, twist-spun carbon nanotube yarns as electrolyte-free muscles that provide fast, high-force, large-stroke torsional and tensile actuation. More than a million torsional and tensile actuation cycles are demonstrated, wherein a muscle spins a rotor at an average 11,500 revolutions/minute or delivers 3% tensile contraction at 1200 cycles/minute. Electrical, chemical, or photonic excitation of hybrid yarns changes guest dimensions and generates torsional rotation and contraction of the yarn host. Demonstrations include torsional motors, contractile muscles, and sensors that capture the energy of the sensing process to mechanically actuate.

  4. Influence of imbalance on distortion in optical push-pull frontends

    NASA Astrophysics Data System (ADS)

    Hagensen, Morten

    1995-04-01

    The influence of imbalance on second-order inter-modulation distortion (IMD2) in optical push-pull frontends for Subcarrier Multiplex CATV applications is investigated theoretically and experimentally. The investigation focuses on imbalance introduced in either the photodiode, the push-pull amplifier, or the output balun, and expressions describing the overall IMD2 cancellation efficiency are derived. The developed theory is used to predict the IMD2 cancellation behavior of an optical push-pull fronted. Commercially available PIN photodiodes for CATV purposes and ferrite core transformers are characterised for phase and amplitude balance up to 1 GHz. The overall IMD2 cancellation efficiency of an optical push-pull frontend based on the best of these devices is calculated. The theory is finally verified experimentally with an optical push-pull frontend designed with the characterised photodiode and transformer. The improvement in IMD2 suppression obtained with the push-pull structure relative to a single-ended structure is in average 29 dB across the band from 47-862 MHz. The total IMD2 suppression obtained for the frontend is between 60 dBc and 79 dBc at an average optical input power of 1 mW and with an optical modulation index (OMI) of 35% per carrier in a two-tone setup.

  5. Comparison of Aedes aegypti (Diptera: Culicidae) resting behavior on two fabric types under consideration for insecticide treatment in a push-pull strategy.

    PubMed

    Tainchum, Krajana; Polsomboon, Suppaluck; Grieco, John P; Suwonkerd, Wannapa; Prabaripai, Atchariya; Sungvornyothin, Sungsit; Chareonviriyaphap, Theeraphap; Achee, Nicole L

    2013-01-01

    Aedes aegypti (L.), the primary vector of dengue and dengue hemorrhagic fever, breeds and rests predominately inside human dwellings. With no current vaccine available, vector control remains the mainstay for dengue management and novel approaches continue to be needed to reduce virus transmission. This requires a full understanding of Ae. aegypti ecology to design effective strategies. One novel approach is the use of contact irritants at target resting sites inside homes to make the surface unacceptable and cause vectors to escape before biting. The objective of the current study was to observe indoor resting behavior patterns of female Ae. aegypti within experimental huts in response to two fabrics under consideration for insecticide treatment: cotton and polyester. Results indicate that fabric type, coverage ratio of dark to light fabric and placement configuration (vertical vs. horizontal) all influenced the resting pattern of mosquito cohorts. Findings from this study will guide evaluations of a push-pull strategy designed to exploit contact irritant behaviors and drive Ae. aegypti out of homes prefeeding.

  6. Risks to human health and estuarine ecology posed by pulling out creosote-treated timber on oyster farms.

    PubMed

    Smith, Paul T

    2008-01-31

    Five oyster farms in Port Stephens, Australia were studied to identify consequences of using creosote-treated posts and the risks posed by removing the posts. Gas chromatography coupled with mass spectrometry (GC/MS) was used to measure polycyclic aromatic hydrocarbons (PAHs) and phenols in sediments, timber, water and oyster tissue. Before posts were removed, the total PAHs in surface sediment on farms was 24.1 mgkg(-1) dry weight. This increased to 45.5 mgkg(-1) dry weight after the posts were pulled out and remained significantly higher 6 months later at 59.7 mgkg(-1) dry weight. A similar increase was found in deeper sediments. The sediment attached to creosote-treated posts had a total concentration of PAHs of 484-2642 mgkg(-1) dry weight, while the corresponding value for the sediment on tar-treated posts was only 30.7 mgkg(-1) dry weight. The surface timber of creosote-treated posts had high levels of PAHs and an average post contained 43 g of PAHs. The total PAHs dispersed to the environment when a creosote-treated post was pulled out was at least 0.67 g. The main species were PAHs with low-molecular weights: fluoranthene, phenanthrene, pyrene, acenaphthylene and chrysene. Benzo(a)pyrene represented 1-10% of PAHs in most samples. Bioassays with creosote-contaminated sediment revealed that Sydney rock oysters (Saccostrea glomerate) and Pacific oysters (Crassostrea gigas) accumulated PAHs at (mgkg(-1) wet tissue weight): 11.3-15.3 and 35.5-47.9, respectively, when exposed for 5 days to water with < 1 microgl(-1) PAHs. Wild oysters growing on creosote-treated posts had high levels of phenols (0.09-6.92 mgkg(-1) wet weight) and PAHs (0.59-1.01 mgkg(-1) wet weight). The dilemma posed by removing creosote-treated posts and dispersing carcinogenic, bioavailable contaminants needs to be managed in light of risks to human health and estuarine ecology.

  7. 75 FR 11559 - Certain Combed Cotton Yarns: Effect of Modification of U.S.-Bahrain FTA Rules of Origin

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-11

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. Bahrain-FTA-103-025] Certain Combed Cotton Yarns.... 3805 note), the Commission instituted investigation No. Bahrain FTA-103-025, Certain Combed Cotton... rules of origin to the FTA for certain combed cotton yarns used in the production of certain home...

  8. Hair Pulling (Trichotillomania)

    MedlinePlus

    ... for Families - Vietnamese Spanish Facts for Families Guide Hair Pulling (Trichotillomania) No. 96; Reviewed July 2013 It ... for children and adolescents to play with their hair. However, frequent or obsessive hair pulling can lead ...

  9. Thermal annealing effects on multi-walled carbon nanotube yarns probed by Raman spectroscopy.

    PubMed

    Pierlot, Anthony P; Woodhead, Andrea L; Church, Jeffrey S

    2014-01-03

    The realized mechanical properties of CNT macrostructures such as webs and yarns remain significantly lower than those of the individual CNTs. Structural changes induced by thermal annealing under inert atmosphere were assessed using Raman spectroscopy. Annealing above 1000 °C resulted in a marked decrease in the D/G ratio which can be attributed to an increase in the crystallite size or the distance between defects. The band component parameters obtained by spectral deconvolution reveal that the D band peak maximum shifts to slightly higher energy with increased annealing temperature. In contrast, the energy of the G band did not change. The full widths at half height (FWHH) of the D and G bands are seen to decrease with increasing annealing temperature. The tensile properties of the yarns have been investigated and it was found that the yarn tenacity did not improve with these structural changes. The effect of impurities in the annealing system such as oxygen, adsorbed water or organic surface contamination was also investigated. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  10. Effects of (Oxy-)Fluorination on Various High-Performance Yarns.

    PubMed

    Kruppke, Iris; Bartusch, Matthias; Hickmann, Rico; Hund, Rolf-Dieter; Cherif, Chokri

    2016-08-26

    In this work, typical high-performance yarns are oxy-fluorinated, such as carbon fibers, ultra-high-molecular-weight polyethylene, poly(p-phenylene sulfide) and poly(p-phenylene terephthalamide). The focus is on the property changes of the fiber surface, especially the wetting behavior, structure and chemical composition. Therefore, contact angle, XPS and tensile strength measurements are performed on treated and untreated fibers, while SEM is utilized to evaluate the surface structure. Different results for the fiber materials are observed. While polyethylene exhibits a relevant impact on both surface and bulk properties, polyphenylene terephthalamide and polyphenylene sulfide are only affected slightly by (oxy-)fluorination. The wetting of carbon fiber needs higher treatment intensities, but in contrast to the organic fibers, even its textile-physical properties are enhanced by the treatment. Based on these findings, the capability of (oxy-)fluorination to improve the adhesion of textiles in fiber-reinforced composite materials can be derived.

  11. Fiber and fabric solar cells by directly weaving carbon nanotube yarns with CdSe nanowire-based electrodes

    NASA Astrophysics Data System (ADS)

    Zhang, Luhui; Shi, Enzheng; Ji, Chunyan; Li, Zhen; Li, Peixu; Shang, Yuanyuan; Li, Yibin; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai; Cao, Anyuan

    2012-07-01

    Electrode materials are key components for fiber solar cells, and when combined with active layers (for light absorption and charge generation) in appropriate ways, they enable design and fabrication of efficient and innovative device structures. Here, we apply carbon nanotube yarns as counter electrodes in combination with CdSe nanowire-grafted primary electrodes (Ti wire) for making fiber and fabric-shaped photoelectrochemical cells with power conversion efficiencies in the range 1% to 2.9%. The spun-twist long nanotube yarns possess both good electrical conductivity and mechanical flexibility compared to conventional metal wires or carbon fibers, which facilitate fabrication of solar cells with versatile configurations. A unique feature of our process is that instead of making individual fiber cells, we directly weave single or multiple nanotube yarns with primary electrodes into a functional fabric. Our results demonstrate promising applications of semiconducting nanowires and carbon nanotubes in woven photovoltaics.Electrode materials are key components for fiber solar cells, and when combined with active layers (for light absorption and charge generation) in appropriate ways, they enable design and fabrication of efficient and innovative device structures. Here, we apply carbon nanotube yarns as counter electrodes in combination with CdSe nanowire-grafted primary electrodes (Ti wire) for making fiber and fabric-shaped photoelectrochemical cells with power conversion efficiencies in the range 1% to 2.9%. The spun-twist long nanotube yarns possess both good electrical conductivity and mechanical flexibility compared to conventional metal wires or carbon fibers, which facilitate fabrication of solar cells with versatile configurations. A unique feature of our process is that instead of making individual fiber cells, we directly weave single or multiple nanotube yarns with primary electrodes into a functional fabric. Our results demonstrate promising applications

  12. Characteristics and phenomenology of hair-pulling: an exploration of subtypes.

    PubMed

    du Toit, P L; van Kradenburg, J; Niehaus, D J; Stein, D J

    2001-01-01

    This study was designed to detail the demographic and phenomenological features of adult chronic hair-pullers. Key possible subtypes were identified a priori. On the basis of the phenomenological data, differences between the following possible subtypes were investigated: hair-pullers with and without DSM-IV trichotillomania (TTM), oral habits, automatic versus focused hair-pulling, positive versus negative affective cues prior to hair-pulling, comorbid self-injurious habits, obsessive-compulsive disorder (OCD), and tics. Forty-seven participants were drawn from an outpatient population of chronic adult hair-pullers. A structured interview that focused on hair-pulling and associated behaviors was administered to participants. Six of the participants (12.8%) were male, and 41 (87.7%) were female. A large number of hair-pullers (63.8%) had comorbid self-injurious habits. A greater proportion of male hair-pullers had comorbid tics when compared with females. Certain subgroups of chronic hair-pullers (e.g., hairpullers with or without automatic/focused hair-pulling, comorbid self-injurious habits, and oral habits) were found to differ on a number of phenomenological and hair-pulling characteristics. However, differences between other possible subgroups (e.g., hair-pullers with or without DSM-IV TTM, comorbid OCD, and negative versus positive affective cues) may reflect greater severity in hair-pulling symptomatology rather than distinct subtypes of chronic hair-pulling. The findings of the present study also indicated that chronic hair-pulling (even in cases where DSM-IV criteria for TTM were not met) has a significant impact on quality of life. The present study provided limited support for the existence of possible subtypes of chronic hair-pulling. Recommendations are made for further investigations into such subtypes. Copyright 2001 by W.B. Saunders Company

  13. Proximal half angle of the screw thread is a critical design variable affecting the pull-out strength of cancellous bone screws.

    PubMed

    Wang, Yingxu; Mori, Ryuji; Ozoe, Nobuaki; Nakai, Takahisa; Uchio, Yuji

    2009-11-01

    Screws with strong pull-out strength have been sought for the treatment of cancellous bone. We hypothesized that an obliquely angled screw thread has advantages over conventional vertical thread with a minimal proximal half angle. Metal and bone screws were made of stainless steel and porcine cortical bone. Their proximal half angle was set at 0 degrees , 30 degrees , or 60 degrees . The screws were inserted into porcine cancellous bone. At 0 degrees , the thread faced the recipient bone vertically. Pullout tests at a rate of 30 mm/min (n=40, each screw type) and microcomputed tomography (n=6) were conducted. The pull-out strength of the screws was maximal at 30 degrees ; 348.8 (SD, 44.1)N with metal and 326.6 (39.4)N with bone. It was intermediate at 0 degrees ; 301.9 (35.9)N with metal and 278.2 (30.6)N with bone. It was minimal at 60 degrees; 126.5 (39.0)N with metal and 174.8 (29.7)N with bone. Cancellous bone was damaged between the threads at 30 degrees , while intact cancellous bone was preserved between the threads at 0 degrees. A proximal half angle of around 30 degrees is appropriate because the pullout force is applied to the recipient bone evenly. Commercial cancellous screws can be improved by changing the thread shape to minimize the damage to recipient bone.

  14. Friction pull plug welding: chamfered heat sink pull plug design

    NASA Technical Reports Server (NTRS)

    Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

    2005-01-01

    The average strength of a pull plug weld is increased and weak bonding eliminated by providing a dual included angle at the top one third of the pull plug. Plugs using the included angle of the present invention had consistent high strength, no weak bonds and were substantially defect free. The dual angle of the pull plug body increases the heat and pressure of the weld in the region of the top one third of the plug. This allows the plug to form a tight high quality solid state bond. The dual angle was found to be successful in elimination of defects on both small and large plugs.

  15. Development of Flame Resistant Combat Uniform Fabrics Made from Long Staple Wool and Aramid Blend Yarn

    DTIC Science & Technology

    2013-04-15

    Kentwool recombed the wool top ( wool is first combed during the production of wool top); a second combing process is an optional step sometimes used in...RESISTANT COMBAT UNIFORM FABRICS MADE FROM LONG STAPLE WOOL AND ARAMID BLEND YARN by Parvez Mehta* Mitchell Driggers* and Carole...SUBTITLE DEVELOPMENT OF FLAME RESISTANT COMBAT UNIFORM FABRICS MADE FROM LONG STAPLE WOOL AND ARAMID BLEND YARN 5a. CONTRACT NUMBER W911QY-11

  16. Push-pull tracer tests: Their information content and use for characterizing non-Fickian, mobile-immobile behavior: INFORMATION CONTENT OF PUSH-PULL TESTS

    DOE PAGES

    Hansen, Scott K.; Berkowitz, Brian; Vesselinov, Velimir V.; ...

    2016-12-01

    Path reversibility and radial symmetry are often assumed in push-pull tracer test analysis. In reality, heterogeneous flow fields mean that both assumptions are idealizations. In this paper, to understand their impact, we perform a parametric study which quantifies the scattering effects of ambient flow, local-scale dispersion, and velocity field heterogeneity on push-pull breakthrough curves and compares them to the effects of mobile-immobile mass transfer (MIMT) processes including sorption and diffusion into secondary porosity. We identify specific circumstances in which MIMT overwhelmingly determines the breakthrough curve, which may then be considered uninformative about drift and local-scale dispersion. Assuming path reversibility, wemore » develop a continuous-time-random-walk-based interpretation framework which is flow-field-agnostic and well suited to quantifying MIMT. Adopting this perspective, we show that the radial flow assumption is often harmless: to the extent that solute paths are reversible, the breakthrough curve is uninformative about velocity field heterogeneity. Our interpretation method determines a mapping function (i.e., subordinator) from travel time in the absence of MIMT to travel time in its presence. A mathematical theory allowing this function to be directly “plugged into” an existing Laplace-domain transport model to incorporate MIMT is presented and demonstrated. Algorithms implementing the calibration are presented and applied to interpretation of data from a push-pull test performed in a heterogeneous environment. A successful four-parameter fit is obtained, of comparable fidelity to one obtained using a million-node 3-D numerical model. In conclusion, we demonstrate analytically and numerically how push-pull tests quantifying MIMT are sensitive to remobilization, but not immobilization, kinetics.« less

  17. Push-pull tracer tests: Their information content and use for characterizing non-Fickian, mobile-immobile behavior: INFORMATION CONTENT OF PUSH-PULL TESTS

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

    Hansen, Scott K.; Berkowitz, Brian; Vesselinov, Velimir V.

    Path reversibility and radial symmetry are often assumed in push-pull tracer test analysis. In reality, heterogeneous flow fields mean that both assumptions are idealizations. In this paper, to understand their impact, we perform a parametric study which quantifies the scattering effects of ambient flow, local-scale dispersion, and velocity field heterogeneity on push-pull breakthrough curves and compares them to the effects of mobile-immobile mass transfer (MIMT) processes including sorption and diffusion into secondary porosity. We identify specific circumstances in which MIMT overwhelmingly determines the breakthrough curve, which may then be considered uninformative about drift and local-scale dispersion. Assuming path reversibility, wemore » develop a continuous-time-random-walk-based interpretation framework which is flow-field-agnostic and well suited to quantifying MIMT. Adopting this perspective, we show that the radial flow assumption is often harmless: to the extent that solute paths are reversible, the breakthrough curve is uninformative about velocity field heterogeneity. Our interpretation method determines a mapping function (i.e., subordinator) from travel time in the absence of MIMT to travel time in its presence. A mathematical theory allowing this function to be directly “plugged into” an existing Laplace-domain transport model to incorporate MIMT is presented and demonstrated. Algorithms implementing the calibration are presented and applied to interpretation of data from a push-pull test performed in a heterogeneous environment. A successful four-parameter fit is obtained, of comparable fidelity to one obtained using a million-node 3-D numerical model. In conclusion, we demonstrate analytically and numerically how push-pull tests quantifying MIMT are sensitive to remobilization, but not immobilization, kinetics.« less

  18. Friction pull plug welding: chamfered heat sink pull plug design

    NASA Technical Reports Server (NTRS)

    Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

    2002-01-01

    Friction Pull Plug Welding (FPPW) is a solid state repair process for defects up to one inch in length, only requiring single sided tooling (OSL) for usage on flight hardware. Experimental data has shown that the mass of plug heat sink remaining above the top of the plate surface after a weld is completed (the plug heat sink) affects the bonding at the plug top. A minimized heat sink ensures complete bonding of the plug to the plate at the plug top. However, with a minimal heat sink three major problems can arise, the entire plug could be pulled through the plate hole, the central portion of the plug could be separated along grain boundaries, or the plug top hat can be separated from the body. The Chamfered Heat Sink Pull Plug Design allows for complete bonding along the ISL interface through an outside diameter minimal mass heat sink, while maintaining enough central mass in the plug to prevent plug pull through, central separation, and plug top hat separation.

  19. The Development of an IMU Integrated Clothes for Postural Monitoring Using Conductive Yarn and Interconnecting Technology.

    PubMed

    Kang, Sung-Won; Choi, Hyeob; Park, Hyung-Il; Choi, Byoung-Gun; Im, Hyobin; Shin, Dongjun; Jung, Young-Giu; Lee, Jun-Young; Park, Hong-Won; Park, Sukyung; Roh, Jung-Sim

    2017-11-07

    Spinal disease is a common yet important condition that occurs because of inappropriate posture. Prevention could be achieved by continuous posture monitoring, but most measurement systems cannot be used in daily life due to factors such as burdensome wires and large sensing modules. To improve upon these weaknesses, we developed comfortable "smart wear" for posture measurement using conductive yarn for circuit patterning and a flexible printed circuit board (FPCB) for interconnections. The conductive yarn was made by twisting polyester yarn and metal filaments, and the resistance per unit length was about 0.05 Ω/cm. An embroidered circuit was made using the conductive yarn, which showed increased yield strength and uniform electrical resistance per unit length. Circuit networks of sensors and FPCBs for interconnection were integrated into clothes using a computer numerical control (CNC) embroidery process. The system was calibrated and verified by comparing the values measured by the smart wear with those measured by a motion capture camera system. Six subjects performed fixed movements and free computer work, and, with this system, we were able to measure the anterior/posterior direction tilt angle with an error of less than 4°. The smart wear does not have excessive wires, and its structure will be optimized for better posture estimation in a later study.

  20. Yarning/Aboriginal storytelling: towards an understanding of an Indigenous perspective and its implications for research practice.

    PubMed

    Geia, Lynore K; Hayes, Barbara; Usher, Kim

    2013-12-01

    There is increasing recognition of Indigenous perspectives from various parts of the world in relation to storytelling, research and its effects on practice. The recent emergence of storytelling or yarning as a research method in Australian Aboriginal and Torres Strait Island studies and other Indigenous peoples of the world is gaining momentum. Narratives, stories, storytelling and yarning are emerging methods in research and has wide ranging potential to shape conventional research discourse making research more meaningful and accessible for researchers. In this paper we argue for the importance of Indigenous research methods and Indigenous method(ology), within collaborative respectful partnerships with non-Indigenous researchers. It is imperative to take these challenging steps together towards better outcomes for Indigenous people and their communities. In the Australian context we as researchers cannot afford to allow the gap between Aboriginal and Torres Strait Islanders and mainstream Australia health outcomes to grow even wider. One such pathway is the inclusion of Aboriginal storytelling or yarning from an Aboriginal and Torres Strait perspective within Indigenous and non-Indigenous research paradigms. Utilising Aboriginal storytelling or yarning will provide deeper understanding; complementing a two-way research paradigm for collaborative research. Furthermore, it has significant social implications for research and clinical practice amongst Indigenous populations; thus complementing the biomedical medical paradigm.

  1. Weavable, Conductive Yarn-Based NiCo//Zn Textile Battery with High Energy Density and Rate Capability.

    PubMed

    Huang, Yan; Ip, Wing Shan; Lau, Yuen Ying; Sun, Jinfeng; Zeng, Jie; Yeung, Nga Sze Sea; Ng, Wing Sum; Li, Hongfei; Pei, Zengxia; Xue, Qi; Wang, Yukun; Yu, Jie; Hu, Hong; Zhi, Chunyi

    2017-09-26

    With intrinsic safety and much higher energy densities than supercapacitors, rechargeable nickel/cobalt-zinc-based textile batteries are promising power sources for next generation personalized wearable electronics. However, high-performance wearable nickel/cobalt-zinc-based batteries are rarely reported because there is a lack of industrially weavable and knittable highly conductive yarns. Here, we use scalably produced highly conductive yarns uniformly covered with zinc (as anode) and nickel cobalt hydroxide nanosheets (as cathode) to fabricate rechargeable yarn batteries. They possess a battery level capacity and energy density, as well as a supercapacitor level power density. They deliver high specific capacity of 5 mAh cm -3 and energy densities of 0.12 mWh cm -2 and 8 mWh cm -3 (based on the whole solid battery). They exhibit ultrahigh rate capabilities of 232 C (liquid electrolyte) and 116 C (solid electrolyte), which endows the batteries excellent power densities of 32.8 mW cm -2 and 2.2 W cm -3 (based on the whole solid battery). These are among the highest values reported so far. A wrist band battery is further constructed by using a large conductive cloth woven from the conductive yarns by a commercial weaving machine. It powers various electronic devices successfully, enabling dual functions of wearability and energy storage.

  2. Structural CNT Composites Part II: Assessment of CNT Yarns as Reinforcement for Composite Overwrapped Pressure Vessels

    NASA Technical Reports Server (NTRS)

    Kim, Jae-Woo; Sauti, Godfrey; Cano, Roberto J.; Wincheski, Russell A.; Ratcliffe, James G.; Czabaj, Michael; Siochi, Emilie J.

    2015-01-01

    Carbon nanotubes (CNTs) are one-dimensional nanomaterials with outstanding electrical and thermal conductivities and mechanical properties. This combination of properties offers routes to enable lightweight structural aerospace components. Recent advances in the manufacturing of CNTs have made bulk forms such as yarns, tapes and sheets available in commercial quantities to permit the evaluation of these materials for aerospace use, where the superior tensile properties of CNT composites can be exploited in tension dominated applications such as composite overwrapped pressure vessels (COPVs). To investigate their utility in this application, aluminum rings were overwrapped with thermoset/CNT yarn composite and their mechanical properties measured. CNT composite overwrap characteristics such as processing method, CNT/resin ratio, and applied tension during CNT yarn winding were varied to determine their effects on the mechanical performance of the CNT composite overwrapped Al rings (CCOARs). Mechanical properties of the CCOARs were measured under static and cyclic loads at room, elevated, and cryogenic temperatures to evaluate their mechanical performance relative to bare Al rings. At room temperature, the breaking load of CCOARs with a 10.8% additional weight due to the CNT yarn/thermoset overwrap increased by over 200% compared to the bare Al ring. The quality of the wound CNT composites was also investigated using x-ray computed tomography.

  3. Verbal Feedback in Therapeutic Communities: Pull-ups and Reciprocated Pull-ups as Predictors of Graduation

    PubMed Central

    Warren, Keith; Hiance, Danielle; Doogan, Nathan; De Leon, George; Phillips, Gary

    2012-01-01

    The most important proximal outcomes for residents of therapeutic communities (TCs) are retention and successful completion of the program. At this point there has been no quantitative analysis of the relationship between the exchange of corrective reminders, or pull-ups, between peers in TCs and graduation. This study draws on a database of pull-ups exchanged between 5,464 residents of three Midwestern TCs. Residents who send more pull-ups to peers and who reciprocate pull-ups with a larger percentage of peers are more likely to graduate. Residents who receive more pull-ups from peers and staff and a larger percentage of whose peers reciprocate pull-ups that they send are less likely to graduate. Implications of these findings for program theory and program improvement are discussed. PMID:23068980

  4. Bio-inspired, Moisture-Powered Hybrid Carbon Nanotube Yarn Muscles

    PubMed Central

    Kim, Shi Hyeong; Kwon, Cheong Hoon; Park, Karam; Mun, Tae Jin; Lepró, Xavier; Baughman, Ray H.; Spinks, Geoffrey M.; Kim, Seon Jeong

    2016-01-01

    Hygromorph artificial muscles are attractive as self-powered actuators driven by moisture from the ambient environment. Previously reported hygromorph muscles have been largely limited to bending or torsional motions or as tensile actuators with low work and energy densities. Herein, we developed a hybrid yarn artificial muscle with a unique coiled and wrinkled structure, which can be actuated by either changing relative humidity or contact with water. The muscle provides a large tensile stroke (up to 78%) and a high maximum gravimetric work capacity during contraction (2.17 kJ kg−1), which is over 50 times that of the same weight human muscle and 5.5 times higher than for the same weight spider silk, which is the previous record holder for a moisture driven muscle. We demonstrate an automatic ventilation system that is operated by the tensile actuation of the hybrid muscles caused by dew condensing on the hybrid yarn. This self-powered humidity-controlled ventilation system could be adapted to automatically control the desired relative humidity of an enclosed space. PMID:26973137

  5. Electrospinning of single wall carbon nanotube reinforced aligned fibrils and yarns

    NASA Astrophysics Data System (ADS)

    Lam, Hoa Le

    Commercial carbon fibers produced from a polyacrylonitrile (PAN) precursor have reached their performance limit. The approach in this study involves the use of single carbon nanotubes (SWNT) with an ultra-high elastic modulus of approximately ˜1 TPa and tensile strength of ˜37 GPa at a breaking strain of ˜6% to reinforce PAN. In order to translate these extraordinary properties to a higher order structure, the need for a media to carry and assemble the SWNT into continuous fibers or yarns is necessary. Effective translation of properties can only be achieved through uniform distribution of SWNT and their alignment in the fiber axis. This has been one of the major challenges since SWNTs tend to agglomerate due to high van der Waals attraction between tubes. It is the goal of this study to develop dispersion technique(s) for the SWNT and process them into aligned fibers utilizing the electrospinning process. The electrospun nanofibers were then characterized by various techniques such as ESEM, Raman microspectroscopy, HRTEM, and tensile testing. Composite nanofibers containing various contents of SWNT up to 10 wt. % with diameter ranging from 40--300 nm were successfully electrospun through varying the polymer concentration and spinning parameters. The inclusion of SWNTs and their alignment in the fiber axis were confirmed by Raman microspectroscopy, polarized Raman and HRETEM. The failure mechanism of the nanofibers was investigated by HRTEM through fiber surface fracture. A two stage rupture mechanism was observed where crazing initiates at a surface defect followed by SWNTs pulling out of the PAN matrix. Such mechanisms consume energy therefore strengthening and toughening the fibers. Mechanical drawing of the fiber prior to heat treatment induced molecular orientation resulting in oriented graphite layers in the carbonized fibers. This study has established a processing base and characterization techniques to support the design and development of SWNT

  6. An investigation of density measurement method for yarn-dyed woven fabrics based on dual-side fusion technique

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Xin, Binjie

    2016-08-01

    Yarn density is always considered as the fundamental structural parameter used for the quality evaluation of woven fabrics. The conventional yarn density measurement method is based on one-side analysis. In this paper, a novel density measurement method is developed for yarn-dyed woven fabrics based on a dual-side fusion technique. Firstly, a lab-used dual-side imaging system is established to acquire both face-side and back-side images of woven fabric and the affine transform is used for the alignment and fusion of the dual-side images. Then, the color images of the woven fabrics are transferred from the RGB to the CIE-Lab color space, and the intensity information of the image extracted from the L component is used for texture fusion and analysis. Subsequently, three image fusion methods are developed and utilized to merge the dual-side images: the weighted average method, wavelet transform method and Laplacian pyramid blending method. The fusion efficacy of each method is evaluated by three evaluation indicators and the best of them is selected to do the reconstruction of the complete fabric texture. Finally, the yarn density of the fused image is measured based on the fast Fourier transform, and the yarn alignment image could be reconstructed using the inverse fast Fourier transform. Our experimental results show that the accuracy of density measurement by using the proposed method is close to 99.44% compared with the traditional method and the robustness of this new proposed method is better than that of conventional analysis methods.

  7. Biomechanical evaluation of different suture techniques for arthroscopic transtibial pull-out repair of posterior medial meniscus root tears.

    PubMed

    Feucht, Matthias J; Grande, Eduardo; Brunhuber, Johannes; Burgkart, Rainer; Imhoff, Andreas B; Braun, Sepp

    2013-12-01

    A tear of the posterior medial meniscus root (PMMR) is increasingly recognized as a serious knee joint injury. Several suture techniques for arthroscopic transtibial pull-out repair have been described; however, only limited data about the biomechanical properties of these techniques are currently available. There are significant differences between the tested suture techniques, with more complex suture configurations providing superior biomechanical properties. Controlled laboratory study. A total of 40 porcine medial menisci were randomly assigned to 1 of 4 groups (10 specimens each) according to suture technique: two simple stitches (TSS), horizontal mattress suture (HMS), modified Mason-Allen suture (MMA), and two modified loop stitches (TLS). Meniscus-suture constructs were subjected to cyclic loading followed by load-to-failure testing in a servohydraulic material testing machine. During cyclic loading, the HMS and TLS groups showed a significantly higher displacement after 100, 500, and 1000 cycles compared with the TSS and MMA groups. After 1000 cycles, the highest displacement was found for the TLS group, with significant differences compared with all other groups. During load-to-failure testing, the highest maximum load and yield load were observed for the MMA group, with statistically significant differences compared with the TSS and TLS groups. With regard to stiffness, the TSS and MMA groups showed significantly higher values compared with the HMS and TLS groups. The MMA technique provided the best biomechanical properties with regard to cyclic loading and load-to-failure testing. The TSS technique seems to be a valuable alternative. Both the HMS and TLS techniques have the disadvantage of lower stiffness and higher displacement during cyclic loading. Using a MMA technique may improve healing rates and avoid progressive extrusion of the medial meniscus after transtibial pull-out repair of PMMR tears. The TSS technique may be used as an alternative that

  8. Pull out strength calculator for pedicle screws using a surrogate ensemble approach.

    PubMed

    Varghese, Vicky; Ramu, Palaniappan; Krishnan, Venkatesh; Saravana Kumar, Gurunathan

    2016-12-01

    Pedicle screw instrumentation is widely used in the treatment of spinal disorders and deformities. Currently, the surgeon decides the holding power of instrumentation based on the perioperative feeling which is subjective in nature. The objective of the paper is to develop a surrogate model which will predict the pullout strength of pedicle screw based on density, insertion angle, insertion depth and reinsertion. A Taguchi's orthogonal array was used to design an experiment to find the factors effecting pullout strength of pedicle screw. The pullout studies were carried using polyaxial pedicle screw on rigid polyurethane foam block according to American society for testing of materials (ASTM F543). Analysis of variance (ANOVA) and Tukey's honestly significant difference multiple comparison tests were done to find factor effect. Based on the experimental results, surrogate models based on Krigging, polynomial response surface and radial basis function were developed for predicting the pullout strength for different combination of factors. An ensemble of these surrogates based on weighted average surrogate model was also evaluated for prediction. Density, insertion depth, insertion angle and reinsertion have a significant effect (p <0.05) on pullout strength of pedicle screw. Weighted average surrogate performed the best in predicting the pull out strength amongst the surrogate models considered in this study and acted as insurance against bad prediction. A predictive model for pullout strength of pedicle screw was developed using experimental values and surrogate models. This can be used in pre-surgical planning and decision support system for spine surgeon. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Foil Strain Gauges Using Piezoresistive Carbon Nanotube Yarn: Fabrication and Calibration

    PubMed Central

    Góngora-Rubio, Mário R.; Kiyono, César Y.; Mello, Luis A. M.; Cardoso, Valtemar F.; Rosa, Reinaldo L. S.; Kuebler, Derek A.; Brodeur, Grace E.; Alotaibi, Amani H.; Coene, Marisa P.; Coene, Lauren M.; Jean, Elizabeth; Santiago, Rafael C.; Oliveira, Francisco H. A.; Rangel, Ricardo; Thomas, Gilles P.; Belay, Kalayu; da Silva, Luciana W.; Moura, Rafael T.; Seabra, Antonio C.; Silva, Emílio C. N.

    2018-01-01

    Carbon nanotube yarns are micron-scale fibers comprised by tens of thousands of carbon nanotubes in their cross section and exhibiting piezoresistive characteristics that can be tapped to sense strain. This paper presents the details of novel foil strain gauge sensor configurations comprising carbon nanotube yarn as the piezoresistive sensing element. The foil strain gauge sensors are designed using the results of parametric studies that maximize the sensitivity of the sensors to mechanical loading. The fabrication details of the strain gauge sensors that exhibit the highest sensitivity, based on the modeling results, are described including the materials and procedures used in the first prototypes. Details of the calibration of the foil strain gauge sensors are also provided and discussed in the context of their electromechanical characterization when bonded to metallic specimens. This characterization included studying their response under monotonic and cyclic mechanical loading. It was shown that these foil strain gauge sensors comprising carbon nanotube yarn are sensitive enough to capture strain and can replicate the loading and unloading cycles. It was also observed that the loading rate affects their piezoresistive response and that the gauge factors were all above one order of magnitude higher than those of typical metallic foil strain gauges. Based on these calibration results on the initial sensor configurations, new foil strain gauge configurations will be designed and fabricated, to increase the strain gauge factors even more. PMID:29401745

  10. Sucrose Treated Carbon Nanotube and Graphene Yarns and Sheets

    NASA Technical Reports Server (NTRS)

    Sauti, Godfrey (Inventor); Kim, Jae-Woo (Inventor); Siochi, Emilie J. (Inventor); Wise, Kristopher E. (Inventor)

    2017-01-01

    Consolidated carbon nanotube or graphene yarns and woven sheets are consolidated through the formation of a carbon binder formed from the dehydration of sucrose. The resulting materials, on a macro-scale are lightweight and of a high specific modulus and/or strength. Sucrose is relatively inexpensive and readily available, and the process is therefore cost-effective.

  11. Analysis of CFRP Joints by Means of T-Pull Mechanical Test and Ultrasonic Defects Detection.

    PubMed

    Casavola, Caterina; Palano, Fania; De Cillis, Francesco; Tati, Angelo; Terzi, Roberto; Luprano, Vincenza

    2018-04-18

    Defects detection within a composite component, with the aim of understanding and predicting its mechanical behavior, is of great importance in the aeronautical field because the irregularities of the composite material could compromise functionality. The aim of this paper is to detect defects by means of non-destructive testing (NDT) on T-pull samples made by carbon fiber reinforced polymers (CFRP) and to evaluate their effect on the mechanical response of the material. Samples, obtained from an industrial stringer having an inclined web and realized with a polymeric filler between cap and web, were subjected to ultrasonic monitoring and then to T-pull mechanical tests. All samples were tested with the same load mode and the same test configuration. An experimental set-up consisting of a semiautomatic C-scan ultrasonic mapping system with a phased array probe was designed and developed, optimizing control parameters and implementing image processing software. The present work is carried out on real composites parts that are characterized by having their intrinsic defectiveness, as opposed to the previous similar results in the literature mainly obtained on composite parts with artificially produced defects. In fact, although samples under study were realized free from defects, ultrasonic mapping found defectiveness inside the material. Moreover, the ultrasonic inspection could be useful in detecting both the location and size of defects. Experimental data were critically analyzed and qualitatively correlated with results of T-pull mechanical tests in order to better understand and explain mechanical behavior in terms of fracture mode.

  12. Analysis of CFRP Joints by Means of T-Pull Mechanical Test and Ultrasonic Defects Detection

    PubMed Central

    Casavola, Caterina; Palano, Fania; De Cillis, Francesco; Tati, Angelo; Terzi, Roberto; Luprano, Vincenza

    2018-01-01

    Defects detection within a composite component, with the aim of understanding and predicting its mechanical behavior, is of great importance in the aeronautical field because the irregularities of the composite material could compromise functionality. The aim of this paper is to detect defects by means of non-destructive testing (NDT) on T-pull samples made by carbon fiber reinforced polymers (CFRP) and to evaluate their effect on the mechanical response of the material. Samples, obtained from an industrial stringer having an inclined web and realized with a polymeric filler between cap and web, were subjected to ultrasonic monitoring and then to T-pull mechanical tests. All samples were tested with the same load mode and the same test configuration. An experimental set-up consisting of a semiautomatic C-scan ultrasonic mapping system with a phased array probe was designed and developed, optimizing control parameters and implementing image processing software. The present work is carried out on real composites parts that are characterized by having their intrinsic defectiveness, as opposed to the previous similar results in the literature mainly obtained on composite parts with artificially produced defects. In fact, although samples under study were realized free from defects, ultrasonic mapping found defectiveness inside the material. Moreover, the ultrasonic inspection could be useful in detecting both the location and size of defects. Experimental data were critically analyzed and qualitatively correlated with results of T-pull mechanical tests in order to better understand and explain mechanical behavior in terms of fracture mode. PMID:29669992

  13. Altered tibiofemoral contact mechanics due to lateral meniscus posterior horn root avulsions and radial tears can be restored with in situ pull-out suture repairs.

    PubMed

    LaPrade, Christopher M; Jansson, Kyle S; Dornan, Grant; Smith, Sean D; Wijdicks, Coen A; LaPrade, Robert F

    2014-03-19

    An avulsion of the posterior root attachment of the lateral meniscus or a radial tear close to the root attachment can lead to degenerative knee arthritis. Although the biomechanical effects of comparable injuries involving the medial meniscus have been studied, we are aware of no such study involving the lateral meniscus. We hypothesized that in situ pull-out suture repair of lateral meniscus root avulsions and of complete radial tears 3 and 6 mm from the root attachment would increase the contact area and decrease mean and peak tibiofemoral contact pressures, at all knee flexion angles, relative to the corresponding avulsion or tear condition. Eight human cadaveric knees underwent biomechanical testing. Eight lateral meniscus conditions (intact, footprint tear, root avulsion, root avulsion repair, radial tears at 3 and 6 mm from the posterior root, and repairs of the 3 and 6-mm tears) were tested at five different flexion angles (0°, 30°, 45°, 60°, and 90°) under a compressive 1000-N load. Avulsion of the posterior root of the lateral meniscus or an adjacent radial tear resulted in significantly decreased contact area and increased mean and peak contact pressures in the lateral compartment, relative to the intact condition, in all cases except the root avulsion condition at 0° of flexion. In situ pull-out suture repair of the root avulsion or radial tear significantly reduced mean contact pressures, relative to the corresponding avulsion or tear condition, when the results for each condition were pooled across all flexion angles. Posterior horn root avulsions and radial tears adjacent to the root attachment of the lateral meniscus significantly increased contact pressures in the lateral compartment. In situ pull-out suture repairs of these tears significantly improved lateral compartment joint contact pressures. In situ repair may be an effective treatment to improve tibiofemoral contact profiles after an avulsion of the posterior root of the lateral

  14. The Development of an IMU Integrated Clothes for Postural Monitoring Using Conductive Yarn and Interconnecting Technology

    PubMed Central

    Kang, Sung-Won; Park, Hyung-Il; Choi, Byoung-Gun; Shin, Dongjun; Jung, Young-Giu; Lee, Jun-Young; Park, Hong-Won; Park, Sukyung

    2017-01-01

    Spinal disease is a common yet important condition that occurs because of inappropriate posture. Prevention could be achieved by continuous posture monitoring, but most measurement systems cannot be used in daily life due to factors such as burdensome wires and large sensing modules. To improve upon these weaknesses, we developed comfortable “smart wear” for posture measurement using conductive yarn for circuit patterning and a flexible printed circuit board (FPCB) for interconnections. The conductive yarn was made by twisting polyester yarn and metal filaments, and the resistance per unit length was about 0.05 Ω/cm. An embroidered circuit was made using the conductive yarn, which showed increased yield strength and uniform electrical resistance per unit length. Circuit networks of sensors and FPCBs for interconnection were integrated into clothes using a computer numerical control (CNC) embroidery process. The system was calibrated and verified by comparing the values measured by the smart wear with those measured by a motion capture camera system. Six subjects performed fixed movements and free computer work, and, with this system, we were able to measure the anterior/posterior direction tilt angle with an error of less than 4°. The smart wear does not have excessive wires, and its structure will be optimized for better posture estimation in a later study. PMID:29112125

  15. Friction Pull Plug and Material Configuration for Anti-Chatter Friction Pull Plug Weld

    NASA Technical Reports Server (NTRS)

    Littell, Justin Anderson (Inventor)

    2016-01-01

    A friction pull plug is provided for use in forming a plug weld in a hole in a material. The friction pull plug includes a shank and a series of three frustoconical sections. The relative sizes of the sections assure that a central one of the sections defines the initial contact point between the hole's sides. The angle defined by the central one of the sections reduces or eliminates chatter as the plug is pulled into the hole.

  16. Comparison of polyester, film-yarn composite, balloon materials subjected to shear and biaxial loading

    NASA Technical Reports Server (NTRS)

    Niccum, R. J.

    1972-01-01

    A series of candidate materials for use in large balloons was tested and their tensile and shear strength capabilities were compared. The tests were done in a cold box at -68 C (-90 F). Some of these materials were fabricated on a special machine called the flying thread loom. This machine laminates various patterns of polyester yarn to a thin polyester film. The results show that the shear strength of materials changes with the angle selected for the transverse yarns, and substantial increases in biaxial load carrying capabilities, compared to materials formerly used, are possible. The loom capabilities and the test methods are discussed.

  17. An eco-friendly dyeing of woolen yarn by Terminalia chebula extract with evaluations of kinetic and adsorption characteristics

    PubMed Central

    Shabbir, Mohd; Rather, Luqman Jameel; Shahid-ul-Islam; Bukhari, Mohd Nadeem; Shahid, Mohd; Ali Khan, Mohd; Mohammad, Faqeer

    2016-01-01

    In the present study Terminalia chebula was used as an eco-friendly natural colorant for sustainable textile coloration of woolen yarn with primary emphasis on thermodynamic and kinetic adsorption aspects of dyeing processes. Polyphenols and ellagitannins are the main coloring components of the dye extract. Assessment of the effect of pH on dye adsorption showed an increase in adsorption capacity with decreasing pH. Effect of temperature on dye adsorption showed 80 °C as optimum temperature for wool dyeing with T. chebula dye extract. Two kinetic equations, namely pseudo first-order and pseudo second-order equations, were employed to investigate the adsorption rates. Pseudo second-order model provided the best fit (R2 = 0.9908) to the experimental data. The equilibrium adsorption data were fitted by Freundlich and Langmuir isotherm models. The adsorption behavior accorded well (R2 = 0.9937) with Langmuir isotherm model. Variety of eco-friendly and sustainable shades were developed in combination with small amount of metallic mordants and assessed in terms of colorimetric (CIEL∗a∗b∗ and K/S) properties measured using spectrophotometer under D65 illuminant (10° standard observer). The fastness properties of dyed woolen yarn against light, washing, dry and wet rubbing were also evaluated. PMID:27222752

  18. An eco-friendly dyeing of woolen yarn by Terminalia chebula extract with evaluations of kinetic and adsorption characteristics.

    PubMed

    Shabbir, Mohd; Rather, Luqman Jameel; Shahid-Ul-Islam; Bukhari, Mohd Nadeem; Shahid, Mohd; Ali Khan, Mohd; Mohammad, Faqeer

    2016-05-01

    In the present study Terminalia chebula was used as an eco-friendly natural colorant for sustainable textile coloration of woolen yarn with primary emphasis on thermodynamic and kinetic adsorption aspects of dyeing processes. Polyphenols and ellagitannins are the main coloring components of the dye extract. Assessment of the effect of pH on dye adsorption showed an increase in adsorption capacity with decreasing pH. Effect of temperature on dye adsorption showed 80 °C as optimum temperature for wool dyeing with T. chebula dye extract. Two kinetic equations, namely pseudo first-order and pseudo second-order equations, were employed to investigate the adsorption rates. Pseudo second-order model provided the best fit (R (2) = 0.9908) to the experimental data. The equilibrium adsorption data were fitted by Freundlich and Langmuir isotherm models. The adsorption behavior accorded well (R (2) = 0.9937) with Langmuir isotherm model. Variety of eco-friendly and sustainable shades were developed in combination with small amount of metallic mordants and assessed in terms of colorimetric (CIEL(∗) a (∗) b (∗) and K/S) properties measured using spectrophotometer under D65 illuminant (10° standard observer). The fastness properties of dyed woolen yarn against light, washing, dry and wet rubbing were also evaluated.

  19. Wearable Self-Charging Power Textile Based on Flexible Yarn Supercapacitors and Fabric Nanogenerators.

    PubMed

    Pu, Xiong; Li, Linxuan; Liu, Mengmeng; Jiang, Chunyan; Du, Chunhua; Zhao, Zhenfu; Hu, Weiguo; Wang, Zhong Lin

    2016-01-06

    A novel and scalable self-charging power textile is realized by combining yarn supercapacitors and fabric triboelectric nanogenerators as energy-harvesting devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Pull-pull position control of dual motor wire rope transmission.

    PubMed

    Guo, Quan; Jiao, Zongxia; Yan, Liang; Yu, Qian; Shang, Yaoxing

    2016-08-01

    Wire rope transmission is very efficient because of the small total moving object mass. The wire rope could only transmit pulling force. Therefore it has to be kept in a tightened state during transmission; in high speed applications the dynamic performance depends on the rope's stiffness, which can be adjusted by the wire rope tension. To improve the system dynamic performance output, this paper proposes a novel pull-pull method based on dual motors connected by wire ropes, for precise, high speed position control applications. The method can regulate target position and wire rope tension simultaneously. Wire ropes remain in a pre-tightening state at all times, which prevents the influence of elasticity and reduces the position tracking error in the changing direction process. Simulations and experiments were conducted; the results indicate that both position precision and superior dynamic performance can be synchronously achieved. The research is relevant to space craft precision pointing instruments.

  1. Pulled elbow in children.

    PubMed

    Yamanaka, Syunsuke; Goldman, Ran D

    2018-06-01

    Question Our practice is seeing children with relatively minor injuries to their elbows, with a history of "swinging" them when their hands are being held to cross the road. Nothing is usually found on a physical examination. I know that this is likely a "pulled elbow." Can we manage this in the clinic setting rather than sending the family to the emergency department? What would be the best course of action in the clinic setting? Answer Pulled elbow, also called nursemaid's elbow , is a radial head subluxation caused by axial traction or a sudden pull of the extended pronated arm, and it is a very common phenomenon. The practice of swinging children while holding their hands should be abandoned. In the case of pulled elbow, the child usually avoids moving the affected arm, holding it close to his or her body, without considerable pain, and no obvious swelling or deformity can be seen. While a fracture should be excluded, pulled elbow can usually be identified based on this presentation. The reduction procedure can easily be done in the office setting, with an 80% success rate and no complications. The hyperpronation maneuver (holding the elbow at 90° and then firmly pronating the wrist) to reduce pulled elbow has been found to be better than a supination-flexion maneuver (holding the elbow at 90° with one hand, supinating and flexing the elbow rapidly with the other) and should be exercised first. When 2 trials of reduction are unsuccessful, the child's arm should be splinted and the family should be sent for further evaluation. Copyright© the College of Family Physicians of Canada.

  2. The study about the improvement of the quality for the fabrics made of chenille yarn

    NASA Astrophysics Data System (ADS)

    Hristian, L.; Ostafe, M. M.; Manea, L. R.; Leon, A. L.

    2016-08-01

    The work is a study about the decrease of the serious defects from the fabrics such as: the deviations from quality or the high costs, discovered and seized by customers. The analyzed fabrics have in their structures three types of different chenille yarns, such as: the Article A1 (viscose fiber with cotton, Nm 3500 dyed coil), the Article A2 (textured polyester, Nm 8000 dyed coil), the Article A3 (Trevira CS polyester, Nm 3000 the pre-dyed raw materials). The technology of chenille yarn, regardless of composition and properties is the same and is performed on the twisting machines. This study has found that the most of the flaws in the fabric, noticed by customers, are caused by the production technology of the chenille yarns. In any organization which makes goods, there are concerns about the improvement of the quality through the elimination of the nonquality. It is extremely difficult to get to “zero defects” but the first step is a systematic action plan to reduce drastically the nonconformities and the defects. The continuous improvement of the effectiveness of the integrated quality and environmental management is achieved by applying the PDCA methodology: planning, development, control, action.

  3. Ultrasonic Evaluation of the Pull-Off Adhesion between Added Repair Layer and a Concrete Substrate

    NASA Astrophysics Data System (ADS)

    Czarnecki, Slawomir

    2017-10-01

    This paper concerns the evaluation of the pull-off adhesion between a concrete added repair layer with variable thickness and a concrete substrate, based on parameters assessed using ultrasonic pulse velocity (UPV) method. In construction practice, the experimental determination of pull-off adhesion f b, between added repair layer and a concrete substrate is necessary to assess the quality of repair. This is usually carried out with the use of pull-off method which results in local damage of the added concrete layer in all the testing areas. Bearing this in mind, it is important to describe the method without these disadvantages. The prediction of the pull-off adhesion of the two-layer concrete elements with variable thickness of each layer might be provided by means of UPV method with two-sided access to the investigated element. For this purpose, two-layered cylindrical specimens were obtained by drilling the borehole from a large size specially prepared concrete element. Those two-layer elements were made out of concrete substrate layer and Polymer Cement Concrete (PCC) mortar as an added repair layer. The values of pull-off adhesion f b of the elements were determined before obtaining the samples by using the semi-destructive pull-off method. The ultrasonic wave velocity was determined in samples with variable thickness of each layer and was then compared to theoretical ultrasonic wave velocity predicted for those specimens. The regression curve for the dependence of velocity and pull-off adhesion, determined by the pulloff method, was made. It has been proved that together with an increase of ratio of investigated ultrasonic wave velocity divided by theoretical ultrasonic wave velocity, the pull-off adhesion value f b between added repair layer with variable thickness and a substrate layer also increases.

  4. 30 CFR 75.828 - Trailing cable pulling.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Trailing cable pulling. 75.828 Section 75.828... Longwalls § 75.828 Trailing cable pulling. The trailing cable must be de-energized prior to being pulled by... procedures must be followed when pulling the trailing cable with equipment other than the continuous mining...

  5. Mitigating Oscillator Pulling Due To Magnetic Coupling in Monolithic Mixed-Signal Radio-Frequency Integrated Circuits

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

    Sobering, Ian David

    2014-01-01

    An analysis of frequency pulling in a varactor-tuned LC VCO under coupling from an on-chip PA is presented. The large-signal behavior of the VCO's inversion-mode MOS varactors is outlined, and the susceptibility of the VCO to frequency pulling from PA aggressor signals with various modulation schemes is discussed. We show that if the aggressor signal is aperiodic, band-limited, or amplitude-modulated, the varactor-tuned LC VCO will experience frequency pulling due to time-modulation of the varactor capacitance. However, if the aggressor signal has constant-envelope phase modulation, VCO pulling can be eliminated, even in the presence of coupling, through careful choice of VCOmore » frequency and divider ratio. Additional mitigation strategies, including new inductor topologies and system-level architectural choices, are also examined.« less

  6. Behavior Modification Project: Reducing and Controlling Calling Out Behaviors.

    ERIC Educational Resources Information Center

    James, Deborah Anne

    The purpose of this study was to determine which behavior modification procedures were the most effective in reducing and controlling the inappropriate calling out behavior of a fifth-grade socially and emotionally disturbed student. Three phases of interventions were involved. As the study began, the resource room instructor was using a behavior…

  7. Comparative relationship of fiber strength and yarn tenacity in four cotton cultivars

    USDA-ARS?s Scientific Manuscript database

    High volume instrumentation (HVITM) measurement is a primary and routine tool of providing fiber properties to cotton researchers. There have been considerable studies designed to derive yarn quality from acquired fiber quality data by various means, including HVI. There is also of desired informati...

  8. Self-Induced Backaction Optical Pulling Force

    NASA Astrophysics Data System (ADS)

    Zhu, Tongtong; Cao, Yongyin; Wang, Lin; Nie, Zhongquan; Cao, Tun; Sun, Fangkui; Jiang, Zehui; Nieto-Vesperinas, Manuel; Liu, Yongmin; Qiu, Cheng-Wei; Ding, Weiqiang

    2018-03-01

    We achieve long-range and continuous optical pulling in a periodic photonic crystal background, which supports a unique Bloch mode with the self-collimation effect. Most interestingly, the pulling force reported here is mainly contributed by the intensity gradient force originating from the self-induced backaction of the object to the self-collimation mode. This force is sharply distinguished from the widely held conception of optical tractor beams based on the scattering force. Also, this pulling force is insensitive to the angle of incidence and can pull multiple objects simultaneously.

  9. Blunt Trauma Performance of Fabric Systems Utilizing Natural Rubber Coated High Strength Fabrics

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

    Ahmad, M. R.; Ahmad, W. Y. W.; Samsuri, A.

    2010-03-11

    The blunt trauma performance of fabric systems against 9 mm bullets is reported. Three shots were fired at each fabric system with impact velocity of 367+-9 m/s and the depth of indentation on the modeling clay backing was measured. The results showed that 18-layer and 21-layer all-neat fabric systems failed the blunt trauma test. However, fabric systems with natural rubber (NR) latex coated fabric layers gave lower blunt trauma of between 25-32 mm indentation depths. Deformations on the neat fabrics upon impact were identified as broken yarns, yarn stretching and yarn pull-out. Deflections of the neat fabrics were more localised.more » For the NR latex coated fabric layers, no significant deformation can be observed except for peeled-off regions of the NR latex film at the back surface of the last layer. From the study, it can be said that the NR latex coated fabric layers were effective in reducing the blunt trauma of fabric systems.« less

  10. Yarn-dyed fabric defect classification based on convolutional neural network

    NASA Astrophysics Data System (ADS)

    Jing, Junfeng; Dong, Amei; Li, Pengfei

    2017-07-01

    Considering that the manual inspection of the yarn-dyed fabric can be time consuming and less efficient, a convolutional neural network (CNN) solution based on the modified AlexNet structure for the classification of the yarn-dyed fabric defect is proposed. CNN has powerful ability of feature extraction and feature fusion which can simulate the learning mechanism of the human brain. In order to enhance computational efficiency and detection accuracy, the local response normalization (LRN) layers in AlexNet are replaced by the batch normalization (BN) layers. In the process of the network training, through several convolution operations, the characteristics of the image are extracted step by step, and the essential features of the image can be obtained from the edge features. And the max pooling layers, the dropout layers, the fully connected layers are also employed in the classification model to reduce the computation cost and acquire more precise features of fabric defect. Finally, the results of the defect classification are predicted by the softmax function. The experimental results show the capability of defect classification via the modified Alexnet model and indicate its robustness.

  11. Delayed pull-in transitions in overdamped MEMS devices

    NASA Astrophysics Data System (ADS)

    Gomez, Michael; Moulton, Derek E.; Vella, Dominic

    2018-01-01

    We consider the dynamics of overdamped MEMS devices undergoing the pull-in instability. Numerous previous experiments and numerical simulations have shown a significant increase in the pull-in time under DC voltages close to the pull-in voltage. Here the transient dynamics slow down as the device passes through a meta-stable or bottleneck phase, but this slowing down is not well understood quantitatively. Using a lumped parallel-plate model, we perform a detailed analysis of the pull-in dynamics in this regime. We show that the bottleneck phenomenon is a type of critical slowing down arising from the pull-in transition. This allows us to show that the pull-in time obeys an inverse square-root scaling law as the transition is approached; moreover we determine an analytical expression for this pull-in time. We then compare our prediction to a wide range of pull-in time data reported in the literature, showing that the observed slowing down is well captured by our scaling law, which appears to be generic for overdamped pull-in under DC loads. This realization provides a useful design rule with which to tune dynamic response in applications, including state-of-the-art accelerometers and pressure sensors that use pull-in time as a sensing mechanism. We also propose a method to estimate the pull-in voltage based only on data of the pull-in times.

  12. Positive and negative communicative behaviors in coming-out conversations.

    PubMed

    Manning, Jimmie

    2015-01-01

    This essay features typographic analysis of 258 coming-out narratives from 130 diverse lesbian, gay, or bisexual participants. Two typologies of coming-out conversations, one exploring positive communicative behaviors and another exploring negative, are offered. Positive behaviors for all members of the conversation include open communication channels, affirming direct relational statements, laughter and joking, and nonverbal immediacy. Negative behaviors for those coming out included nervous nonverbal behavior, indirectly approaching the topic, and lack of preparation. Negative behaviors for receivers include expressing denial, religious talk, inappropriate questions or comments, shaming statements, and aggressive statements. Future studies and research implications are considered.

  13. Foot placement strategy in pushing and pulling.

    PubMed

    Lee, Tzu-Hsien

    2018-01-01

    Pushing and pulling tasks are very common in daily and industrial workplaces. They are one major source of musculoskeletal complaints. This study aimed to examine the foot placement strategy while pushing and pulling. Thirteen young males and ten young females were recruited as participants. A two (pushing and pulling) by four (48 cm, 84 cm, 120 cm, and 156 cm) factorial design was used. Exertion direction and exertion height significantly affected foot placement strategy. Pushing task needed more anteroposterior space than pulling task. The percentages of female/male for trailing foot position ranged from 77% to 90% (pushing) and from 80% to 93% (pulling) across the exertion heights. Practitioners should provide an anteroposterior space approximately to 70% body stature for workers to exert their maximum pulling and pushing strengths.

  14. Thermo-mechanical behavior of stainless steel knitted structures

    NASA Astrophysics Data System (ADS)

    Hamdani, Syed Talha Ali; Fernando, Anura; Maqsood, Muhammad

    2016-09-01

    Heating fabric is an advanced textile material that is extensively researched by the industrialists and the scientists alike. Ability to create highly flexible and drapeable heating fabrics has many applications in everyday life. This paper presents a study conducted on the comparison of heatability of knitted fabric made of stainless steel yarn. The purpose of the study is to find a suitable material for protective clothing against cold environments. In the current research the ampacity of stainless steel yarn is observed in order to prevent the overheating of the heating fabrics. The behavior of the knitted structure is studied for different levels of supply voltage. Infrared temperature sensing is used to measure the heat generated from the fabrics in order to measure the temperature of the fabrics without physical contact. It is concluded that interlock structure is one of the most suited structures for knitted heating fabrics. As learnt through this research, fabrics made of stainless steel yarn are capable of producing a higher level of heating compared to that of knitted fabric made using silver coated polymeric yarn at the same supply voltage.

  15. Relationship of Fiber Properties to Vortex Yarn Quality via Partial Least Squares

    USDA-ARS?s Scientific Manuscript database

    The Cotton Quality Research Station (CQRS) of the USDA-ARS, recently completed a comprehensive study of the relationship of cotton fiber properties to the quality of spun yarn. The five year study, began in 2001, utilized commercial variety cotton grown, harvested and ginned in each of three major ...

  16. Friction Pull Plug Welding in Aluminum Alloys

    NASA Technical Reports Server (NTRS)

    Brooke, Shane A.; Bradford, Vann; Burkholder, Jonathon

    2011-01-01

    NASA fs Marshall Space Flight Center (MSFC) has recently invested much time and effort into the process development of Friction Pull Plug Welding (FPPW). FPPW, is a welding process similar to Friction Push Plug Welding in that, there is a small rotating part (plug) being spun and simultaneously pulled (forged) into a larger part. These two processes differ, in that push plug welding requires an internal reaction support, while pull plug welding reacts to the load externally. FPPW was originally conceived as a post proof repair technique for External Tank. FPPW was easily selected as the primary process used to close out the termination hole on the Constellation Program fs ARES I Upper Stage circumferential Self ] Reacting Friction Stir Welds (SR ]FSW). The versatility of FPPW allows it to also be used as a repair technique for both SR ]FSW and Conventional Friction Stir Welds. To date, all MSFC led development has been concentrated on aluminum alloys (2195, 2219, and 2014). Much work has been done to fully understand and characterize the process fs limitations. A heavy emphasis has been spent on plug design, to match the various weldland thicknesses and alloy combinations. This presentation will summarize these development efforts including weld parameter development, process control, parameter sensitivity studies, plug repair techniques, material properties including tensile, fracture and failure analysis.

  17. Friction Pull Plug Welding in Aluminum Alloys

    NASA Technical Reports Server (NTRS)

    Brooke, Shane A.; Bradford, Vann

    2012-01-01

    NASA's Marshall Space Flight Center (MSFC) has recently invested much time and effort into the process development of Friction Pull Plug Welding (FPPW). FPPW, is a welding process similar to Friction Push Plug Welding in that, there is a small rotating part (plug) being spun and simultaneously pulled (forged) into a larger part. These two processes differ, in that push plug welding requires an internal reaction support, while pull plug welding reacts to the load externally. FPPW was originally conceived as a post proof repair technique for the Space Shuttle fs External Tank. FPPW was easily selected as the primary weld process used to close out the termination hole on the Constellation Program's ARES I Upper Stage circumferential Self-Reacting Friction Stir Welds (SR-FSW). The versatility of FPPW allows it to also be used as a repair technique for both SR-FSW and Conventional Friction Stir Welds. To date, all MSFC led development has been concentrated on aluminum alloys (2195, 2219, and 2014). Much work has been done to fully understand and characterize the process's limitations. A heavy emphasis has been spent on plug design, to match the various weldland thicknesses and alloy combinations. This presentation will summarize these development efforts including weld parameter development, process control, parameter sensitivity studies, plug repair techniques, material properties including tensile, fracture and failure analysis.

  18. Finding the Cell Center by a Balance of Dynein and Myosin Pulling and Microtubule Pushing: A Computational Study

    PubMed Central

    Zhu, Jie; Burakov, Anton; Rodionov, Vladimir

    2010-01-01

    The centrosome position in many types of interphase cells is actively maintained in the cell center. Our previous work indicated that the centrosome is kept at the center by pulling force generated by dynein and actin flow produced by myosin contraction and that an unidentified factor that depends on microtubule dynamics destabilizes position of the centrosome. Here, we use modeling to simulate the centrosome positioning based on the idea that the balance of three forces—dyneins pulling along microtubule length, myosin-powered centripetal drag, and microtubules pushing on organelles—is responsible for the centrosome displacement. By comparing numerical predictions with centrosome behavior in wild-type and perturbed interphase cells, we rule out several plausible hypotheses about the nature of the microtubule-based force. We conclude that strong dynein- and weaker myosin-generated forces pull the microtubules inward competing with microtubule plus-ends pushing the microtubule aster outward and that the balance of these forces positions the centrosome at the cell center. The model also predicts that kinesin action could be another outward-pushing force. Simulations demonstrate that the force-balance centering mechanism is robust yet versatile. We use the experimental observations to reverse engineer the characteristic forces and centrosome mobility. PMID:20980619

  19. Finding the cell center by a balance of dynein and myosin pulling and microtubule pushing: a computational study.

    PubMed

    Zhu, Jie; Burakov, Anton; Rodionov, Vladimir; Mogilner, Alex

    2010-12-01

    The centrosome position in many types of interphase cells is actively maintained in the cell center. Our previous work indicated that the centrosome is kept at the center by pulling force generated by dynein and actin flow produced by myosin contraction and that an unidentified factor that depends on microtubule dynamics destabilizes position of the centrosome. Here, we use modeling to simulate the centrosome positioning based on the idea that the balance of three forces-dyneins pulling along microtubule length, myosin-powered centripetal drag, and microtubules pushing on organelles-is responsible for the centrosome displacement. By comparing numerical predictions with centrosome behavior in wild-type and perturbed interphase cells, we rule out several plausible hypotheses about the nature of the microtubule-based force. We conclude that strong dynein- and weaker myosin-generated forces pull the microtubules inward competing with microtubule plus-ends pushing the microtubule aster outward and that the balance of these forces positions the centrosome at the cell center. The model also predicts that kinesin action could be another outward-pushing force. Simulations demonstrate that the force-balance centering mechanism is robust yet versatile. We use the experimental observations to reverse engineer the characteristic forces and centrosome mobility.

  20. Mechanism of oil-pulling therapy - in vitro study.

    PubMed

    Asokan, Sharath; Rathinasamy, T K; Inbamani, N; Menon, Thangam; Kumar, S Senthil; Emmadi, Pamela; Raghuraman, R

    2011-01-01

    Oil pulling has been used extensively as a traditional Indian folk remedy without scientific proof for many years for strengthening teeth, gums and jaws and to prevent decay, oral malodor, bleeding gums and dryness of throat and cracked lips. The aim of this study was to evaluate the antibacterial activity of sesame oil and lignans isolated from sesame oil on oral microorganisms and to check whether saponification or emulsification occurs during oil-pulling therapy. The in vitro study was carried out in three different phases: (1) Antibacterial activity of the lignans and sesame oil were tested by minimum inhibitory concentration assay by agar dilution method and agar well diffusion method, respectively. (2) Increase in free fatty acid level of oil and the quantity of sodium hydroxide (NaOH) used up in the titration are good indicators of saponification process. This was assessed using analytical tests for vegetable oils. (3) Swished oil was observed under light microscope to assess the status of the oil, presence of microorganisms, oral debris and foreign bodies. Sesamin and sesamolin isolated from sesame oil did not have any antibacterial effect against oral microorganisms like Streptococcus mutans, Streptococcus mitis and Streptococcus viridans. Emulsification of sesame oil occurs during oil-pulling therapy. Increased consumption of NaOH in titration is a definite indication of a possible saponification process. The myth that the effect of oil-pulling therapy on oral health was just a placebo effect has been broken and there are clear indications of possible saponification and emulsification process, which enhances its mechanical cleaning action.

  1. Apparent Covariation between Child Habit Disorders: Effects of Successful Treatment for Thumb Sucking on Untargeted Chronic Hair Pulling.

    ERIC Educational Resources Information Center

    Friman, Patrick C.; Hove, Gayleen

    1987-01-01

    The study examined effects of aversive taste treatment of thumb sucking on untreated habitual hair pulling by two young males (ages 2 and 5). Concomitant with successful treatment of thumb sucking, hair pulling was also eliminated. Results suggest an efficient method for changing behaviors that are difficult to treat directly. (Author/JW)

  2. Fluoroscopy-Guided Pull-Through Gastrostomy

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

    Pitton, M. B., E-mail: pitton@radiologie.klinik.uni-mainz.de; Herber, S.; Dueber, C.

    2008-01-15

    The purpose of this study was to simplify a fluoroscopy guided gastrostomy technique using pull-type tubes which are traditionally introduced with gastroscopic assistance. The stomach was transorally probed with a 5-Fr catheter and a guidewire. A second access was performed percutaneously through the anterior abdominal and gastric wall using an 8-Fr sheath and an 8-Fr guiding catheter. A duplicated guidewire was introduced through the guiding catheter in order to result in a great custom-made loop within the stomach. The transoral guidewire was captured and tightened with this loop and the guiding catheter, and both were subsequently pulled by the transoralmore » guidewire until the tip of the guiding catheter exited the mouth. A thread was fed through the guiding catheter for fixation of the pull-type gastrostomy tube. Finally, the fixed tube was pulled through the esophagus into the stomach and through the abdominal wall until the anterior gastric wall fixed the retention plate of the tube. Thirty-seven patients (28 male, 9 female; age, 65.1 {+-} 14.4 years) with miscellaneous indications for percutaneous gastrostomies were supplied with pull-type gastrostomy catheters in a fluoroscopy technique without endoscopic assistance. Twenty-five of the 37 patients (67.6%) had undergone unsuccessful preceding gastroscopically guided PEG attempts because of tumor stenosis (n = 12) or impossible transillumination of the abdominal wall (n = 13). All procedures were technically successful, without major complications. Particularly, all patients with frustrating gastroscopic attempts were successfully provided with pull-type gastrostomy tubes. Five minor complications occurred: one tube loss during the passage of the hypopoharynx because of a torn thread, one transient small leakage alongside the tube (both successfully treated), and three cases of transient moderate local pain without leakage (symptomatic treatment). We conclude that this fluoroscopy-guided pull

  3. Effect of Electron Beam Irradiation on the Tensile Properties of Carbon Nanotubes Sheets and Yarns

    NASA Technical Reports Server (NTRS)

    Williams, Tiffany S.; Miller, Sandi G.; Baker, James S.; McCorkle, Linda S.; Meador, Michael A.

    2013-01-01

    Carbon nanotube sheets and yarns were irradiated using electron beam (e-beam) energy to determine the effect of irradiation dose on the tensile properties. Results showed that a slight change in tensile strength occurred after irradiating as-received CNT sheets for 20 minutes, and a slight decrease in tensile strength as the irradiation time approached 90 minutes. On the other hand, the addition of small molecules to the CNT sheet surface had a greater effect on the tensile properties of e-beam irradiated CNT sheets. Some functionalized CNT sheets displayed up to a 57% increase in tensile strength following 90 minutes of e-beam exposure. In addition, as-received CNT yarns showed a significant increase in tensile strength as the irradiation time increased.

  4. Production of Banana Fiber Yarns for Technical Textile Reinforced Composites

    PubMed Central

    Ortega, Zaida; Morón, Moisés; Monzón, Mario D.; Badalló, Pere; Paz, Rubén

    2016-01-01

    Natural fibers have been used as an alternative to synthetic ones for their greener character; banana fibers have the advantage of coming from an agricultural residue. Fibers have been extracted by mechanical means from banana tree pseudostems, as a strategy to valorize banana crops residues. To increase the mechanical properties of the composite, technical textiles can be used as reinforcement, instead of short fibers. To do so, fibers must be spun and woven. The aim of this paper is to show the viability of using banana fibers to obtain a yarn suitable to be woven, after an enzymatic treatment, which is more environmentally friendly. Extracted long fibers are cut to 50 mm length and then immersed into an enzymatic bath for their refining. Conditions of enzymatic treatment have been optimized to produce a textile grade of banana fibers, which have then been characterized. The optimum treating conditions were found with the use of Biopectinase K (100% related to fiber weight) at 45 °C, pH 4.5 for 6 h, with bath renewal after three hours. The first spinning trials show that these fibers are suitable to be used for the production of yarns. The next step is the weaving process to obtain a technical fabric for composites production. PMID:28773490

  5. Push-Pull Locomotion for Vehicle Extrication

    NASA Technical Reports Server (NTRS)

    Creager, Colin M.; Johnson, Kyle A.; Plant, Mark; Moreland, Scott J.; Skonieczny, Krzysztof

    2014-01-01

    For applications in which unmanned vehicles must traverse unfamiliar terrain, there often exists the risk of vehicle entrapment. Typically, this risk can be reduced by using feedback from on-board sensors that assess the terrain. This work addressed the situations where a vehicle has already become immobilized or the desired route cannot be traversed using conventional rolling. Specifically, the focus was on using push-pull locomotion in high sinkage granular material. Push-pull locomotion is an alternative mode of travel that generates thrust through articulated motion, using vehicle components as anchors to push or pull against. It has been revealed through previous research that push-pull locomotion has the capacity for generating higher net traction forces than rolling, and a unique optical flow technique indicated that this is the result of a more efficient soil shearing method. It has now been found that pushpull locomotion results in less sinkage, lower travel reduction, and better power efficiency in high sinkage material as compared to rolling. Even when starting from an "entrapped" condition, push-pull locomotion was able to extricate the test vehicle. It is the authors' recommendation that push-pull locomotion be considered as a reliable back-up mode of travel for applications where terrain entrapment is a possibility.

  6. Effect of ecological surface treatment method on friction strength properties of nettle (urtica dioica) fibre yarns

    NASA Astrophysics Data System (ADS)

    Şansal, S.; Mıstık, S. I.; Fettahov, R.; Ovalı, S.; Duman, M.

    2017-10-01

    Over the last few decades, more attention is given to lignocellulose based fibres as reinforcement material in the polymer composites owing to the environmental pollution caused by the extensive usage of synthetic and inorganic fibres. Developing new natural fibre reinforced composites is the focus of many researches nowadays. They are made from renewable resources and they have less environmental effect in comparison to inorganic fibre reinforced composites. The interest of consumers in eco-friendly natural fibres and textiles has increased in recent years. Unlike inorganic fibres, natural fibres present light weight, high strength/density ratio and are readily available, environmentally friendly and biodegradable. Many different types of natural fibres are exploited for the production of biodegradable polymer composites. The nettle (Urtica dioica L.) is a well-known plant growing on rural sites of Europe, Asia, and North America. Nettle plant contains fibre similar to hemp and flax. However, similar to other natural fibres, nettle fibres are poorly compatible with the thermoplastic matrix of composites, due to their hydrophilic character which reduces mechanical properties of nettle fibre reinforced thermoplastics. In order to improve the fibrematrix adhesion of the natural fibre reinforced composites, surface treatment processes are applied to the lignocellulose fibres. In this study nettle (urtica dioica) fibre yarns were treated with NaOH by using conventional, ultrasonic and microwave energy methods. After treatment processes tensile strength, elongation, friction strength and SEM observations of the nettle fibre yarns were investigated. All treatment processes were improved the tensile strength, elongation and friction strength properties of the nettle fibre yarns. Also higher tensile strength, elongation and friction strength properties were obtained from treated nettle fibre yarns which treated by using microwave energy method.

  7. Hybrid nanomembranes for high power and high energy density supercapacitors and their yarn application.

    PubMed

    Lee, Jae Ah; Shin, Min Kyoon; Kim, Shi Hyeong; Kim, Seon Jeong; Spinks, Geoffrey M; Wallace, Gordon G; Ovalle-Robles, Raquel; Lima, Márcio D; Kozlov, Mikhail E; Baughman, Ray H

    2012-01-24

    We report mechanically robust, electrically conductive, free-standing, and transparent hybrid nanomembranes made of densified carbon nanotube sheets that were coated with poly(3,4-ethylenedioxythiophene) using vapor phase polymerization and their performance as supercapacitors. The hybrid nanomembranes with thickness of ~66 nm and low areal density of ~15 μg/cm(2)exhibited high mechanical strength and modulus of 135 MPa and 12.6 GPa, respectively. They also had remarkable shape recovery ability in liquid and at the liquid/air interface unlike previous carbon nanotube sheets. The hybrid nanomembrane attached on a current collector had volumetric capacitance of ~40 F/cm(3) at 100 V s(-1) (~40 and ~80 times larger than that of onion-like carbon measured at 100 V s(-1) and activated carbon measured at 20 V s(-1), respectively), and it showed rectangular shapes of cyclic voltammograms up to ~5 V s(-1). High mechanical strength and flexibility of the hybrid nanomembrane enabled twisting it into microsupercapacitor yarns with diameters of ~30 μm. The yarn supercapacitor showed stable cycling performance without a metal current collector, and its capacitance decrease was only ~6% after 5000 cycles. Volumetric energy and power density of the hybrid nanomembrane was ~70 mWh cm(-3) and ~7910 W cm(-3), and the yarn possessed the energy and power density of ~47 mWh cm(-3) and ~538 W cm(-3). © 2011 American Chemical Society

  8. Angle-Dependent Atomic Force Microscopy Single-Chain Pulling of Adsorbed Macromolecules from Planar Surfaces Unveils the Signature of an Adsorption-Desorption Transition.

    PubMed

    Grebíková, Lucie; Whittington, Stuart G; Vancso, Julius G

    2018-05-23

    The adsorption-desorption behavior of polymer chains is at the heart of macromolecular surface science and technology. With the current developments in atomic force microscopy (AFM), it has now become possible to address the desorption problem from the perspective of a single macromolecule. Here, we report on desorption of single polymer chains on planar surfaces by AFM-based single molecule force spectroscopy (SMFS) as a function of the pulling angle with respect to the surface-normal direction. SMFS experiments were performed in water with various substrates using different polymers covalently attached to the AFM probe tip. End-grafting at the AFM tip was achieved by surface-initiated polymerization using initiator functionalized tips. We found that the desorption force increases with a decreasing pulling angle, i.e., an enhanced adhesion of the polymer chain was observed. The magnitude of the desorption force shows a weak angular dependence at pulling angles close to the surface normal. A significant increase of the force is observed at shallower pulling from a certain pulling angle. This behavior carries the signature of an adsorption-desorption transition. The angular dependence of the normalized desorption force exhibits a universal behavior. We compared and interpreted our results using theoretical predictions for single-chain adsorption-desorption transitions.

  9. Angle-Dependent Atomic Force Microscopy Single-Chain Pulling of Adsorbed Macromolecules from Planar Surfaces Unveils the Signature of an Adsorption–Desorption Transition

    PubMed Central

    2018-01-01

    The adsorption–desorption behavior of polymer chains is at the heart of macromolecular surface science and technology. With the current developments in atomic force microscopy (AFM), it has now become possible to address the desorption problem from the perspective of a single macromolecule. Here, we report on desorption of single polymer chains on planar surfaces by AFM-based single molecule force spectroscopy (SMFS) as a function of the pulling angle with respect to the surface-normal direction. SMFS experiments were performed in water with various substrates using different polymers covalently attached to the AFM probe tip. End-grafting at the AFM tip was achieved by surface-initiated polymerization using initiator functionalized tips. We found that the desorption force increases with a decreasing pulling angle, i.e., an enhanced adhesion of the polymer chain was observed. The magnitude of the desorption force shows a weak angular dependence at pulling angles close to the surface normal. A significant increase of the force is observed at shallower pulling from a certain pulling angle. This behavior carries the signature of an adsorption–desorption transition. The angular dependence of the normalized desorption force exhibits a universal behavior. We compared and interpreted our results using theoretical predictions for single-chain adsorption–desorption transitions. PMID:29712430

  10. Analysis of Pull-In Instability of Geometrically Nonlinear Microbeam Using Radial Basis Artificial Neural Network Based on Couple Stress Theory

    PubMed Central

    Heidari, Mohammad; Heidari, Ali; Homaei, Hadi

    2014-01-01

    The static pull-in instability of beam-type microelectromechanical systems (MEMS) is theoretically investigated. Two engineering cases including cantilever and double cantilever microbeam are considered. Considering the midplane stretching as the source of the nonlinearity in the beam behavior, a nonlinear size-dependent Euler-Bernoulli beam model is used based on a modified couple stress theory, capable of capturing the size effect. By selecting a range of geometric parameters such as beam lengths, width, thickness, gaps, and size effect, we identify the static pull-in instability voltage. A MAPLE package is employed to solve the nonlinear differential governing equations to obtain the static pull-in instability voltage of microbeams. Radial basis function artificial neural network with two functions has been used for modeling the static pull-in instability of microcantilever beam. The network has four inputs of length, width, gap, and the ratio of height to scale parameter of beam as the independent process variables, and the output is static pull-in voltage of microbeam. Numerical data, employed for training the network, and capabilities of the model have been verified in predicting the pull-in instability behavior. The output obtained from neural network model is compared with numerical results, and the amount of relative error has been calculated. Based on this verification error, it is shown that the radial basis function of neural network has the average error of 4.55% in predicting pull-in voltage of cantilever microbeam. Further analysis of pull-in instability of beam under different input conditions has been investigated and comparison results of modeling with numerical considerations shows a good agreement, which also proves the feasibility and effectiveness of the adopted approach. The results reveal significant influences of size effect and geometric parameters on the static pull-in instability voltage of MEMS. PMID:24860602

  11. Push-pull farming systems.

    PubMed

    Pickett, John A; Woodcock, Christine M; Midega, Charles A O; Khan, Zeyaur R

    2014-04-01

    Farming systems for pest control, based on the stimulo-deterrent diversionary strategy or push-pull system, have become an important target for sustainable intensification of food production. A prominent example is push-pull developed in sub-Saharan Africa using a combination of companion plants delivering semiochemicals, as plant secondary metabolites, for smallholder farming cereal production, initially against lepidopterous stem borers. Opportunities are being developed for other regions and farming ecosystems. New semiochemical tools and delivery systems, including GM, are being incorporated to exploit further opportunities for mainstream arable farming systems. By delivering the push and pull effects as secondary metabolites, for example, (E)-4,8-dimethyl-1,3,7-nonatriene repelling pests and attracting beneficial insects, problems of high volatility and instability are overcome and compounds are produced when and where required. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. Force feedback effects on single molecule hopping and pulling experiments

    NASA Astrophysics Data System (ADS)

    Rico-Pasto, M.; Pastor, I.; Ritort, F.

    2018-03-01

    Single-molecule experiments with optical tweezers have become an important tool to study the properties and mechanisms of biological systems, such as cells and nucleic acids. In particular, force unzipping experiments have been used to extract the thermodynamics and kinetics of folding and unfolding reactions. In hopping experiments, a molecule executes transitions between the unfolded and folded states at a preset value of the force [constant force mode (CFM) under force feedback] or trap position [passive mode (PM) without feedback] and the force-dependent kinetic rates extracted from the lifetime of each state (CFM) and the rupture force distributions (PM) using the Bell-Evans model. However, hopping experiments in the CFM are known to overestimate molecular distances and folding free energies for fast transitions compared to the response time of the feedback. In contrast, kinetic rate measurements from pulling experiments have been mostly done in the PM while the CFM is seldom implemented in pulling protocols. Here, we carry out hopping and pulling experiments in a short DNA hairpin in the PM and CFM at three different temperatures (6 °C, 25 °C, and 45 °C) exhibiting largely varying kinetic rates. As expected, we find that equilibrium hopping experiments in the CFM and PM perform well at 6 °C (where kinetics are slow), whereas the CFM overestimates molecular parameters at 45 °C (where kinetics are fast). In contrast, nonequilibrium pulling experiments perform well in both modes at all temperatures. This demonstrates that the same kind of feedback algorithm in the CFM leads to more reliable determination of the folding reaction parameters in irreversible pulling experiments.

  13. Force feedback effects on single molecule hopping and pulling experiments.

    PubMed

    Rico-Pasto, M; Pastor, I; Ritort, F

    2018-03-28

    Single-molecule experiments with optical tweezers have become an important tool to study the properties and mechanisms of biological systems, such as cells and nucleic acids. In particular, force unzipping experiments have been used to extract the thermodynamics and kinetics of folding and unfolding reactions. In hopping experiments, a molecule executes transitions between the unfolded and folded states at a preset value of the force [constant force mode (CFM) under force feedback] or trap position [passive mode (PM) without feedback] and the force-dependent kinetic rates extracted from the lifetime of each state (CFM) and the rupture force distributions (PM) using the Bell-Evans model. However, hopping experiments in the CFM are known to overestimate molecular distances and folding free energies for fast transitions compared to the response time of the feedback. In contrast, kinetic rate measurements from pulling experiments have been mostly done in the PM while the CFM is seldom implemented in pulling protocols. Here, we carry out hopping and pulling experiments in a short DNA hairpin in the PM and CFM at three different temperatures (6 °C, 25 °C, and 45 °C) exhibiting largely varying kinetic rates. As expected, we find that equilibrium hopping experiments in the CFM and PM perform well at 6 °C (where kinetics are slow), whereas the CFM overestimates molecular parameters at 45 °C (where kinetics are fast). In contrast, nonequilibrium pulling experiments perform well in both modes at all temperatures. This demonstrates that the same kind of feedback algorithm in the CFM leads to more reliable determination of the folding reaction parameters in irreversible pulling experiments.

  14. Efficiently detecting outlying behavior in video-game players.

    PubMed

    Kim, Young Bin; Kang, Shin Jin; Lee, Sang Hyeok; Jung, Jang Young; Kam, Hyeong Ryeol; Lee, Jung; Kim, Young Sun; Lee, Joonsoo; Kim, Chang Hun

    2015-01-01

    In this paper, we propose a method for automatically detecting the times during which game players exhibit specific behavior, such as when players commonly show excitement, concentration, immersion, and surprise. The proposed method detects such outlying behavior based on the game players' characteristics. These characteristics are captured non-invasively in a general game environment. In this paper, cameras were used to analyze observed data such as facial expressions and player movements. Moreover, multimodal data from the game players (i.e., data regarding adjustments to the volume and the use of the keyboard and mouse) was used to analyze high-dimensional game-player data. A support vector machine was used to efficiently detect outlying behaviors. We verified the effectiveness of the proposed method using games from several genres. The recall rate of the outlying behavior pre-identified by industry experts was approximately 70%. The proposed method can also be used for feedback analysis of various interactive content provided in PC environments.

  15. Efficiently detecting outlying behavior in video-game players

    PubMed Central

    Kim, Young Bin; Kang, Shin Jin; Lee, Sang Hyeok; Jung, Jang Young; Kam, Hyeong Ryeol; Lee, Jung; Kim, Young Sun; Lee, Joonsoo

    2015-01-01

    In this paper, we propose a method for automatically detecting the times during which game players exhibit specific behavior, such as when players commonly show excitement, concentration, immersion, and surprise. The proposed method detects such outlying behavior based on the game players’ characteristics. These characteristics are captured non-invasively in a general game environment. In this paper, cameras were used to analyze observed data such as facial expressions and player movements. Moreover, multimodal data from the game players (i.e., data regarding adjustments to the volume and the use of the keyboard and mouse) was used to analyze high-dimensional game-player data. A support vector machine was used to efficiently detect outlying behaviors. We verified the effectiveness of the proposed method using games from several genres. The recall rate of the outlying behavior pre-identified by industry experts was approximately 70%. The proposed method can also be used for feedback analysis of various interactive content provided in PC environments. PMID:26713250

  16. Design of RF MEMS switches without pull-in instability

    NASA Astrophysics Data System (ADS)

    Proctor, W. Cyrus; Richards, Gregory P.; Shen, Chongyi; Skorczewski, Tyler; Wang, Min; Zhang, Jingyan; Zhong, Peng; Massad, Jordan E.; Smith, Ralph

    2010-04-01

    Micro-electro-mechanical systems (MEMS) switches for radio-frequency (RF) signals have certain advantages over solid-state switches, such as lower insertion loss, higher isolation, and lower static power dissipation. Mechanical dynamics can be a determining factor for the reliability of RF MEMS. The RF MEMS ohmic switch discussed in this paper consists of a plate suspended over an actuation pad by four double-cantilever springs. Closing the switch with a simple step actuation voltage typically causes the plate to rebound from its electrical contacts. The rebound interrupts the signal continuity and degrades the performance, reliability and durability of the switch. The switching dynamics are complicated by a nonlinear, electrostatic pull-in instability that causes high accelerations. Slow actuation and tailored voltage control signals can mitigate switch bouncing and effects of the pull-in instability; however, slow switching speed and overly-complex input signals can significantly penalize overall system-level performance. Examination of a balanced and optimized alternative switching solution is sought. A step toward one solution is to consider a pull-in-free switch design. In this paper, determine how simple RC-circuit drive signals and particular structural properties influence the mechanical dynamics of an RF MEMS switch designed without a pull-in instability. The approach is to develop a validated modeling capability and subsequently study switch behavior for variable drive signals and switch design parameters. In support of project development, specifiable design parameters and constraints will be provided. Moreover, transient data of RF MEMS switches from laser Doppler velocimetry will be provided for model validation tasks. Analysis showed that a RF MEMS switch could feasibly be designed with a single pulse waveform and no pull-in instability and achieve comparable results to previous waveform designs. The switch design could reliably close in a timely

  17. Influence of molecular designs on polaronic and vibrational transitions in a conjugated push-pull copolymer

    NASA Astrophysics Data System (ADS)

    Cobet, Christoph; Gasiorowski, Jacek; Menon, Reghu; Hingerl, Kurt; Schlager, Stefanie; White, Matthew S.; Neugebauer, Helmut; Sariciftci, N. Serdar; Stadler, Philipp

    2016-10-01

    Electron-phonon interactions of free charge-carriers in doped pi-conjugated polymers are conceptually described by 1-dimensional (1D) delocalization. Thereby, polaronic transitions fit the 1D-Froehlich model in quasi-confined chains. However, recent developments in conjugated polymers have diversified the backbones to become elaborate heterocylcic macromolecules. Their complexity makes it difficult to investigate the electron-phonon coupling. In this work we resolve the electron-phonon interactions in the ground and doped state in a complex push-pull polymer. We focus on the polaronic transitions using in-situ spectroscopy to work out the differences between single-unit and push-pull systems to obtain the desired structural- electronic correlations in the doped state. We apply the classic 1D-Froehlich model to generate optical model fits. Interestingly, we find the 1D-approach in push-pull polarons in agreement to the model, pointing at the strong 1D-character and plain electronic structure of the push-pull structure. In contrast, polarons in the single-unit polymer emerge to a multi- dimensional problem difficult to resolve due to their anisotropy. Thus, we report an enhancement of the 1D-character by the push-pull concept in the doped state - an important view in light of the main purpose of push-pull polymers for photovoltaic devices.

  18. MXene: a potential candidate for yarn supercapacitors.

    PubMed

    Zhang, Jizhen; Seyedin, Shayan; Gu, Zhoujie; Yang, Wenrong; Wang, Xungai; Razal, Joselito M

    2017-12-07

    The increasing developments in wearable electronics demand compatible power sources such as yarn supercapacitors (YSCs) that can effectively perform in a limited footprint. MXene nanosheets, which have been recently shown in the literature to possess ultra-high volumetric capacitance, were used in this study for the fabrication of YSCs in order to identify their potential merit and performance in YSCs. With the aid of a conductive binder (PEDOT-PSS), YSCs with high mass loading of MXene are demonstrated. These MXene-based YSCs exhibit excellent device performance and stability even under bending and twisting. This study demonstrates that MXene is a promising candidate for YSCs and its further development can lead to flexible power sources with sufficient performance for powering miniaturized and/or wearable electronics.

  19. Station Program Note Pull Automation

    NASA Technical Reports Server (NTRS)

    Delgado, Ivan

    2016-01-01

    Upon commencement of my internship, I was in charge of maintaining the CoFR (Certificate of Flight Readiness) Tool. The tool acquires data from existing Excel workbooks on NASA's and Boeing's databases to create a new spreadsheet listing out all the potential safety concerns for upcoming flights and software transitions. Since the application was written in Visual Basic, I had to learn a new programming language and prepare to handle any malfunctions within the program. Shortly afterwards, I was given the assignment to automate the Station Program Note (SPN) Pull process. I developed an application, in Python, that generated a GUI (Graphical User Interface) that will be used by the International Space Station Safety & Mission Assurance team here at Johnson Space Center. The application will allow its users to download online files with the click of a button, import SPN's based on three different pulls, instantly manipulate and filter spreadsheets, and compare the three sources to determine which active SPN's (Station Program Notes) must be reviewed for any upcoming flights, missions, and/or software transitions. Initially, to perform the NASA SPN pull (one of three), I had created the program to allow the user to login to a secure webpage that stores data, input specific parameters, and retrieve the desired SPN's based on their inputs. However, to avoid any conflicts with sustainment, I altered it so that the user may login and download the NASA file independently. After the user has downloaded the file with the click of a button, I defined the program to check for any outdated or pre-existing files, for successful downloads, to acquire the spreadsheet, convert it from a text file to a comma separated file and finally into an Excel spreadsheet to be filtered and later scrutinized for specific SPN numbers. Once this file has been automatically manipulated to provide only the SPN numbers that are desired, they are stored in a global variable, shown on the GUI, and

  20. Energy requirements of tire pulling.

    PubMed

    Fredriksen, Per M; Mamen, Asgeir

    2017-10-01

    We have investigated the effect using walking poles and pulling tires at 4 and 6 km·h-1 (1.11 and 1.67 m·s-1) speeds on oxygen uptake (V̇O2) and heart rate. Eleven subjects, 6 males, with a mean (SD) age of 25.2 (6.9) years participated in field tests involving walking without poles, walking with poles and tire pulling with poles. Increasing the load caused the largest increases in energy demand, more than 4 MET. Speed increase also caused substantial energy increase, approximately 4 MET. Increasing the inclination only modestly increased the oxygen uptake, approximately 2 MET. In both level walking and uphill walking, using poles marginally increased oxygen uptake compared to working without poles. Pulling one tire (12.5 kg) required an oxygen uptake of 27 (4) mL·kg-1·min-1 at 4 km·h-1 and 0% inclination. Adding one more tire (6 kg) drove the oxygen uptake further up to 39 (4) mL·kg-1·min-1. This is close to the requirement of level running at 10.5 km·h-1. Pulling both tires at 6 km·h-1 and 5% inclination required a V̇O2 of 54 (6) mL·kg-1·min-1, equal to running uphill at 5% inclination and 12.5 km·h-1 speed. Heart rate rose comparably with oxygen uptake. At 4 km·h-1 and 0% inclination the increase was 29 bpm, from 134 (21) to 163 (22) bpm when going from pulling one tire to two tires. In the hardest exercise, 6 km·h-1 and 5% inclination, heart rate reached 174 (14) bpm. The study showed that tire pulling even at slow speeds has an energy requirement that is so large that the activity may be feasible as endurance training.

  1. Experiential Avoidance as a Mediator of Relationships between Cognitions and Hair-Pulling Severity

    ERIC Educational Resources Information Center

    Norberg, Melissa M.; Wetterneck, Chad T.; Woods, Douglas W.; Conelea, Christine A.

    2007-01-01

    Cognitive-behavioral models suggest that certain cognitions and beliefs are functionally related to hair pulling in persons with trichotillomania (TTM), but little empirical data have been collected to test such claims. This study assessed dysfunctional beliefs about appearance, shameful cognitions, and fear of negative evaluation and their…

  2. Associative Mechanisms Allow for Social Learning and Cultural Transmission of String Pulling in an Insect

    PubMed Central

    Zhu, Xingfu; Ingraham, Thomas; Søvik, Eirik

    2016-01-01

    Social insects make elaborate use of simple mechanisms to achieve seemingly complex behavior and may thus provide a unique resource to discover the basic cognitive elements required for culture, i.e., group-specific behaviors that spread from “innovators” to others in the group via social learning. We first explored whether bumblebees can learn a nonnatural object manipulation task by using string pulling to access a reward that was presented out of reach. Only a small minority “innovated” and solved the task spontaneously, but most bees were able to learn to pull a string when trained in a stepwise manner. In addition, naïve bees learnt the task by observing a trained demonstrator from a distance. Learning the behavior relied on a combination of simple associative mechanisms and trial-and-error learning and did not require “insight”: naïve bees failed a “coiled-string experiment,” in which they did not receive instant visual feedback of the target moving closer when tugging on the string. In cultural diffusion experiments, the skill spread rapidly from a single knowledgeable individual to the majority of a colony’s foragers. We observed that there were several sequential sets (“generations”) of learners, so that previously naïve observers could first acquire the technique by interacting with skilled individuals and, subsequently, themselves become demonstrators for the next “generation” of learners, so that the longevity of the skill in the population could outlast the lives of informed foragers. This suggests that, so long as animals have a basic toolkit of associative and motor learning processes, the key ingredients for the cultural spread of unusual skills are already in place and do not require sophisticated cognition. PMID:27701411

  3. Relationships of cotton fiber properties to ring-spun yarn quality on selected High Plains cottons

    USDA-ARS?s Scientific Manuscript database

    The objective of this research was to evaluate the adequacy of High Volume Instruement (HVI) and Advanced Fiber Information System (AFIS) fiber quality parameters for predicting quality parameters of ring-spun yarns considering differences in harvest method. Fiber properties measured using the HVI (...

  4. Push-you-pull-you: the boundaried self in close relationships.

    PubMed

    Rempel, John K; Burris, Christopher T

    2006-02-01

    Based on Amoebic Self Theory, the authors propose that the salience of different threats to the self affects the extent to which an intimate relationship partner is pushed away (excluded) or pulled closer (included). When social threat is salient among persons in relationships, it is hypothesized that partners will attempt to defuse the resulting sense of interpersonal vulnerability: offending partners may be pushed away, whereas offenders themselves may draw closer. When spatial-symbolic threat is salient and the relationship's capacity to function as an identity marker is jeopardized, it is hypothesized that the partner--regardless of his or her role--will be pulled closer to maintain the perception that the relationship is secure. Self-report responses to hypothetical scenarios and perceptions of behaviors during a role-play were generally consistent with these hypotheses, suggesting that both an intimate partner and the relationship with that partner can be incorporated into the self.

  5. Damage Tolerance Assessment of Friction Pull Plug Welds

    NASA Technical Reports Server (NTRS)

    McGill, Preston; Burkholder, Jonathan

    2012-01-01

    Friction stir welding is a solid state welding process developed and patented by The Welding Institute in Cambridge, England. Friction stir welding has been implemented in the aerospace industry in the fabrication of longitudinal welds in pressurized cryogenic propellant tanks. As the industry looks to implement friction stir welding in circumferential welds in pressurized cryogenic propellant tanks, techniques to close out the termination hole associated with retracting the pin tool are being evaluated. Friction pull plug welding is under development as a one means of closing out the termination hole. A friction pull plug weld placed in a friction stir weld results in a non-homogenous weld joint where the initial weld, plug weld, their respective heat affected zones and the base metal all interact. The welded joint is a composite, plastically deformed material system with a complex residual stress field. In order to address damage tolerance concerns associated with friction plug welds in safety critical structures, such as propellant tanks, nondestructive inspection and proof testing may be required to screen hardware for mission critical defects. The efficacy of the nondestructive evaluation or the proof test is based on an assessment of the critical flaw size in the test or service environments. Test data relating residual strength capability to flaw size in two aluminum alloy friction plug weld configurations is presented.

  6. CO2 Push-Pull Dual (Conjugate) Faults Injection Simulations

    DOE Data Explorer

    Oldenburg, Curtis (ORCID:0000000201326016); Lee, Kyung Jae; Doughty, Christine; Jung, Yoojin; Borgia, Andrea; Pan, Lehua; Zhang, Rui; Daley, Thomas M.; Altundas, Bilgin; Chugunov, Nikita

    2017-07-20

    This submission contains datasets and a final manuscript associated with a project simulating carbon dioxide push-pull into a conjugate fault system modeled after Dixie Valley- sensitivity analysis of significant parameters and uncertainty prediction by data-worth analysis. Datasets include: (1) Forward simulation runs of standard cases (push & pull phases), (2) Local sensitivity analyses (push & pull phases), and (3) Data-worth analysis (push & pull phases).

  7. Symptom accommodation, trichotillomania-by-proxy, and interpersonal functioning in trichotillomania (hair-pulling disorder).

    PubMed

    Falkenstein, Martha J; Haaga, David A F

    2016-02-01

    This study investigated relationship functioning in trichotillomania (TTM) as well as specific interpersonal behaviors that have received little attention in TTM research, including by-proxy pulling, symptom accommodation, and self-disclosure. The objective was to contribute data for future development of components of treatment that focus on interpersonal functioning. Data were collected through survey about relationships and related difficulties among adults who endorsed criteria consistent with DSM-5 criteria for TTM (n=670). Consistent with our hypotheses, TTM symptom severity was correlated negatively with relationship satisfaction and perceived social support, positively with perceived criticism, perceived risk in intimacy, and social interaction anxiety, though these correlations were small (absolute values r=.08 to .17). Approximately one-quarter of survey respondents had not told their closest friend about their trichotillomania, and one-fifth had not told their spouse or long-term romantic partner. TTM-by-proxy urges were reported by 54% of participants, and 37% of participants reported having actually pulled hair from other people, with the most common proxies specified as significant others (51%), parents (13%), friends (8%), siblings (8%), children (7%) and pets (5%). Higher levels of TTM-by-proxy urges were associated with "focused" pulling (d=.37) and perfectionistic thinking (d=.16 to .20), yet current by-proxy urges were not associated with, functional impairment. A small minority of individuals (7%) reported having asked other people to pull hair for them (78% of these requests were granted); there was increased endorsement of "focused" pulling among these individuals. The people who participants asked to pull hairs for them included significant others (66%), mothers (20%), siblings (11%), friends (9%) and one's children (9%). More than one-third of respondents had pulled hair from others, 7% had asked others to pull their hair, and sizable

  8. Large-Scale CTRW Analysis of Push-Pull Tracer Tests and Other Transport in Heterogeneous Porous Media

    NASA Astrophysics Data System (ADS)

    Hansen, S. K.; Berkowitz, B.

    2014-12-01

    Recently, we developed an alternative CTRW formulation which uses a "latching" upscaling scheme to rigorously map continuous or fine-scale stochastic solute motion onto discrete transitions on an arbitrarily coarse lattice (with spacing potentially on the meter scale or more). This approach enables model simplification, among many other things. Under advection, for example, we see that many relevant anomalous transport problems may be mapped into 1D, with latching to a sequence of successive, uniformly spaced planes. On this formulation (which we term RP-CTRW), the spatial transition vector may generally be made deterministic, with CTRW waiting time distributions encapsulating all the stochastic behavior. We demonstrate the excellent performance of this technique alongside Pareto-distributed waiting times in explaining experiments across a variety of scales using only two degrees of freedom. An interesting new application of the RP-CTRW technique is the analysis of radial (push-pull) tracer tests. Given modern computational power, random walk simulations are a natural fit for the inverse problem of inferring subsurface parameters from push-pull test data, and we propose them as an alternative to the classical type curve approach. In particular, we explore the visibility of heterogeneity through non-Fickian behavior in push-pull tests, and illustrate the ability of a radial RP-CTRW technique to encapsulate this behavior using a sparse parameterization which has predictive value.

  9. Effect on the partial least-squares prediction of yarn properties combining raman and infrared measurements and applying wavelength selection.

    PubMed

    de Groot, P J; Swierenga, H; Postma, G J; Melssen, W J; Buydens, L M C

    2003-06-01

    The combination of Raman and infrared spectroscopy on the one hand and wavelength selection on the other hand is used to improve the partial least-squares (PLS) prediction of seven selected yarn properties. These properties are important for on-line quality control during production. From 71 yarn samples, the Raman and infrared spectra are measured and reference methods are used to determine the selected properties. Making separate PLS models for all yarn properties using the Raman and infrared spectra, prior to wavelength selection, reveals that Raman spectroscopy outperforms infrared spectroscopy. If wavelength selection is applied, the PLS prediction error decreases and the correlation coefficient increases for all properties. However, a substantial wavelength selection effect is present for the infrared spectra compared to the Raman spectra. For the infrared spectra, wavelength selection results in PLS prediction errors comparable with the prediction performance of the Raman spectra prior to wavelength selection. Concatenating the Raman and infrared spectra does not enhance the PLS prediction performance, not even after wavelength selection. It is concluded that an infrared spectrometer, combined with a wavelength selection procedure, can be used if no (suitable) Raman instrument is available.

  10. A new model for impregnation mechanisms in different GF/PP commingled yarns

    NASA Astrophysics Data System (ADS)

    Klinkmüller, V.; Um, M.-K.; Steffens, M.; Friedrich, K.; Kim, B.-S.

    1994-09-01

    Impregnation mechanisms of different kinds of GF/PP commingled yarns have been studied. As the reinforcing fibres were always the same, a global description has been worked out. Two different mathematical approaches for fibre bed permeability (Kozeny-Carman and Gutowski) were compared. The constants of the applied mathematical models have to stay the same if the fibre reeinforcement and the fibre arrangement is the same. Neither the kind of matrix, nor the fibre volume content may change these constants. Differences in the degree of impregnation after the same process conditions can be only due to different sizes of fibre agglomerations, thus the initial distribution of reinforcing fibres and matrix. For an exact determination of impregnation times and conditions the exact distribution of fibres in the intermediate material and after processing has to be known. This distribution is determined by SEM microscopy and data given from the material supplier. The importance of different process parameters, such as temperature, pressure, processing time is weighted by determining the density and mechanical properties of the specimens.

  11. Raman measurements of Kevlar-29 fiber pull-out test at different strain levels

    NASA Astrophysics Data System (ADS)

    Wang, Quan; Lei, Zhenkun; Kang, Yilan; Qiu, Wei

    2008-11-01

    This paper adopted Kevlar-29 fiber monofilament embedding technology to prepare fiber/ epoxy resin tensile specimen. The specimen was pulled on a homemade and portable mini-loading device. At the same time micro-Raman spectroscopy is introduced to detect the distributions of stress on the embedded fiber at different strain levels. The characteristic peak shift of the 1610 cm-1 in Raman band has a linear relationship with the strain or stress. The experimental results show that the fiber axial stress decreases gradually from the embedded fiber-start to the embedded fiber-end at the same strain level. At different strain levels, the fiber axial stress increases along with the applied load. It reveals that there is a larger fiber axial stress distribution under a larger strain level. And the stress transfer is realized gradually from the embedded fiber-start to the fiber-end. Stress concentration exists in the embedded fiber-end, which is a dangerous region for interfacial debonding easily.

  12. Yarning about fall prevention: community consultation to discuss falls and appropriate approaches to fall prevention with older Aboriginal and Torres Strait Islander people.

    PubMed

    Lukaszyk, Caroline; Coombes, Julieann; Turner, Norma Jean; Hillmann, Elizabeth; Keay, Lisa; Tiedemann, Anne; Sherrington, Cathie; Ivers, Rebecca

    2017-08-01

    Fall related injury is an emerging issue for older Indigenous people worldwide, yet few targeted fall prevention programs are currently available for Indigenous populations. In order to inform the development of a new Aboriginal-specific fall prevention program in Australia, we conducted community consultation with older Aboriginal people to identify perceptions and beliefs about falls, and to identify desired program elements. Yarning Circles were held with Aboriginal and Torres Strait Islander people aged 45 years and over. Each Yarning Circle was facilitated by an Aboriginal researcher who incorporated six indicative questions into each discussion. Questions explored the impact of falls on Yarning Circle participants, their current use of fall prevention services and investigated Yarning Circle participant's preferences regarding the design and mode of delivery of a fall prevention program. A total of 76 older Aboriginal people participated in ten Yarning Circles across six sites in the state of New South Wales. Participants associated falls with physical disability, a loss of emotional well-being and loss of connection to family and community. Many participants did not use existing fall prevention services due to a lack of availability in their area, having no referral provided by their GP and/or being unaware of fall prevention programs in general. Program elements identified as important by participants were that it be Aboriginal-specific, group-based, and on-going, with the flexibility to be tailored to specific communities, with free transport provided to and from the program. Older Aboriginal people reported falls to be a priority health issue, with a significant impact on their health and well-being. Few older Aboriginal people accessed prevention programs, suggesting there is an important need for targeted Aboriginal-specific programs. A number of important program elements were identified which if incorporated into prevention programs, may help to

  13. Directional preference in dogs: Laterality and "pull of the north"

    PubMed Central

    Adámková, Jana; Svoboda, Jan; Benediktová, Kateřina; Martini, Sabine; Nováková, Petra; Tůma, David; Kučerová, Michaela; Divišová, Michaela; Begall, Sabine; Hart, Vlastimil

    2017-01-01

    Laterality is a well described phenomenon in domestic dogs. It was shown that dogs, under calm Earth's magnetic field conditions, when marking their home ranges, tend to head about north- or southwards and display thus magnetic alignment. The question arises whether magnetic alignment might be affected or even compromised by laterality and vice versa. We tested the preference of dogs to choose between two dishes with snacks that were placed left and right, in different compass directions (north and east, east and south, south and west or west and north) in front of them. Some dogs were right-lateral, some left-lateral but most of them were ambilateral. There was a preference for the dish placed north compared to the one placed east of the dog ("pull of the north"). This effect was highly significant in small and medium-sized breeds but not in larger breeds, highly significant in females, in older dogs, in lateralized dogs but less significant or not significant in males, younger dogs, or ambilateral dogs. Laterality and “pull of the north” are phenomena which should be considered in diverse tasks and behavioral tests with which dogs or other animals might be confronted. The interaction and possible conflict between lateralization and "pull of the north" might be also considered as a reason for shifted magnetic alignment observed in different animal species in different contexts. PMID:28945773

  14. Directional preference in dogs: Laterality and "pull of the north".

    PubMed

    Adámková, Jana; Svoboda, Jan; Benediktová, Kateřina; Martini, Sabine; Nováková, Petra; Tůma, David; Kučerová, Michaela; Divišová, Michaela; Begall, Sabine; Hart, Vlastimil; Burda, Hynek

    2017-01-01

    Laterality is a well described phenomenon in domestic dogs. It was shown that dogs, under calm Earth's magnetic field conditions, when marking their home ranges, tend to head about north- or southwards and display thus magnetic alignment. The question arises whether magnetic alignment might be affected or even compromised by laterality and vice versa. We tested the preference of dogs to choose between two dishes with snacks that were placed left and right, in different compass directions (north and east, east and south, south and west or west and north) in front of them. Some dogs were right-lateral, some left-lateral but most of them were ambilateral. There was a preference for the dish placed north compared to the one placed east of the dog ("pull of the north"). This effect was highly significant in small and medium-sized breeds but not in larger breeds, highly significant in females, in older dogs, in lateralized dogs but less significant or not significant in males, younger dogs, or ambilateral dogs. Laterality and "pull of the north" are phenomena which should be considered in diverse tasks and behavioral tests with which dogs or other animals might be confronted. The interaction and possible conflict between lateralization and "pull of the north" might be also considered as a reason for shifted magnetic alignment observed in different animal species in different contexts.

  15. Development of sugar palm yarn/glass fibre reinforced unsaturated polyester hybrid composites

    NASA Astrophysics Data System (ADS)

    Nurazzi, N. Mohd; Khalina, A.; Sapuan, S. Mohd; Rahmah, M.

    2018-04-01

    This study investigates the effect of fibre hybridization for sugar palm yarn fibre with glass fibre reinforced with unsaturated polyester composites. In this work, unsaturated polyester resin are reinforced with fibre at a ratio of 70:30 wt% and 60:40 wt%. The hybrid composites were characterized in terms of physical (density and water absorption), mechanical (tensile, flexural and compression) and thermal properties through thermal gravimetry analysis (TGA). Density determination showed that density increased with higher wt% of glass fibre. The inherently higher density of glass fibre increased the density of hybrid composite. Resistance to water absorption is improved upon the incorporation of glass fibre and the hybrid composites were found to reach equilibrium absorption at days 4 and 5. As for mechanical performance, the highest tensile strength, tensile modulus, flexural strength, flexural modulus and compression strength were obtained from 40 wt% of fibres reinforcement with ratio of 50:50 wt% of sugar palm yarn fibre and glass fibre reinforced unsaturated polyester composites. The increase of glass fibre loading had a synergistic effect on the mechanical properties to the composites structure due to its superior strength and modulus. The thermal stability of hybrid composites was improved by the increase of onset temperature and the reduction of residues upon increase in temperature.

  16. Modeling haul-out behavior of walruses in Bering Sea ice

    USGS Publications Warehouse

    Udevitz, M.S.; Jay, C.V.; Fischbach, Anthony S.; Garlich-Miller, J. L.

    2009-01-01

    Understanding haul-out behavior of ice-associated pinnipeds is essential for designing and interpreting popula-tion surveys and for assessing effects of potential changes in their ice environments. We used satellite-linked transmitters to obtain sequential information about location and haul-out state for Pacific walruses, Odobenus rosmarus divergens (Il-liger, 1815), in the Bering Sea during April of 2004, 2005, and 2006. We used these data in a generalized mixed model of haul-out bout durations and a hierarchical Bayesian model of haul-out probabilities to assess factors related to walrus haul-out behavior, and provide the first predictive model of walrus haul-out behavior in sea ice habitat. Average haul-out bout duration was 9 h, but durations of haul-out bouts tended to increase with durations of preceding in-water bouts. On aver-age, tagged walruses spent only about 17% of their time hauled out on sea ice. Probability of being hauled out decreased with wind speed, increased with temperature, and followed a diurnal cycle with the highest values in the evening. Our haul-out probability model can be used to estimate the proportion of the population that is unavailable for detection in spring surveys of Pacific walruses on sea ice.

  17. Construct Related Validity for the Baumgartner Modified Pull-Up Test

    ERIC Educational Resources Information Center

    Baumgartner, Ted A.; Gaunt, Sharon j.

    2005-01-01

    Traditionally the pull-up was used as a measure of arm and shoulder girdle strength and endurance. This measure did not discriminate among ability levels because many zero scores occur. Baumgartner (1978) developed a modified pull-up test that was easier than the traditional pull-up test. The Baumgartner Modified Pull-Up (BMPU) has been used as an…

  18. 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.

  19. Fabrication and preliminary study of a biomimetic tri-layer tubular graft based on fibers and fiber yarns for vascular tissue engineering.

    PubMed

    Wu, Tong; Zhang, Jialing; Wang, Yuanfei; Li, Dandan; Sun, Binbin; El-Hamshary, Hany; Yin, Meng; Mo, Xiumei

    2018-01-01

    Designing a biomimetic and functional tissue-engineered vascular graft has been urgently needed for repairing and regenerating defected vascular tissues. Utilizing a multi-layered vascular scaffold is commonly considered an effective way, because multi-layered scaffolds can easily simulate the structure and function of natural blood vessels. Herein, we developed a novel tri-layer tubular graft consisted of Poly(L-lactide-co-caprolactone)/collagen (PLCL/COL) fibers and Poly(lactide-co-glycolide)/silk fibroin (PLGA/SF) yarns via a three-step electrospinning method. The tri-layer vascular graft consisted of PLCL/COL aligned fibers in inner layer, PLGA/SF yarns in middle layer, and PLCL/COL random fibers in outer layer. Each layer possessed tensile mechanical strength and elongation, and the entire tubular structure provided tensile and compressive supports. Furthermore, the human umbilical vein endothelial cells (HUVECs) and smooth muscle cells (SMCs) proliferated well on the materials. Fluorescence staining images demonstrated that the axially aligned PLCL/COL fibers prearranged endothelium morphology in lumen and the circumferential oriented PLGA/SF yarns regulated SMCs organization along the single yarns. The outside PLCL/COL random fibers performed as the fixed layer to hold the entire tubular structure. The in vivo results showed that the tri-layer vascular graft supported cell infiltration, scaffold biodegradation and abundant collagen production after subcutaneous implantation for 10weeks, revealing the optimal biocompatibility and tissue regenerative capability of the tri-layer graft. Therefore, the specially designed tri-layer vascular graft will be beneficial to vascular reconstruction. Copyright © 2017. Published by Elsevier B.V.

  20. An analysis of the pull strength behaviors of fine-pitch, flip chip solder interconnections using a Au-Pt-Pd thick film conductor on Low-Temperature, Co-fired Ceramic (LTCC) substrates.

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

    Uribe, Fernando R.; Kilgo, Alice C.; Grazier, John Mark

    2008-09-01

    The assembly of the BDYE detector requires the attachment of sixteen silicon (Si) processor dice (eight on the top side; eight on the bottom side) onto a low-temperature, co-fired ceramic (LTCC) substrate using 63Sn-37Pb (wt.%, Sn-Pb) in a double-reflow soldering process (nitrogen). There are 132 solder joints per die. The bond pads were gold-platinum-palladium (71Au-26Pt-3Pd, wt.%) thick film layers fired onto the LTCC in a post-process sequence. The pull strength and failure modes provided the quality metrics for the Sn-Pb solder joints. Pull strengths were measured in both the as-fabricated condition and after exposure to thermal cycling (-55/125 C; 15more » min hold times; 20 cycles). Extremely low pull strengths--referred to as the low pull strength phenomenon--were observed intermittently throughout the product build, resulting in added program costs, schedule delays, and a long-term reliability concern for the detector. There was no statistically significant correlation between the low pull strength phenomenon and (1) the LTCC 'sub-floor' lot; (2) grit blasting the LTCC surfaces prior to the post-process steps; (3) the post-process parameters; (4) the conductor pad height (thickness); (5) the dice soldering assembly sequence; or (5) the dice pull test sequence. Formation of an intermetallic compound (IMC)/LTCC interface caused by thick film consumption during either the soldering process or by solid-state IMC formation was not directly responsible for the low-strength phenomenon. Metallographic cross sections of solder joints from dice that exhibited the low pull strength behavior, revealed the presence of a reaction layer resulting from an interaction between Sn from the molten Sn-Pb and the glassy phase at the TKN/LTCC interface. The thick film porosity did not contribute, explicitly, to the occurrence of reaction layer. Rather, the process of printing the very thin conductor pads was too sensitive to minor thixotropic changes to ink, which resulted in

  1. Molding Helmet Liners from Nylon Cloth Made from 1050 Denier Type 700 Nylon Yarns

    DTIC Science & Technology

    Helmet liners were satisfactorily molded from 14 ounce, 2 x 2 basket- weave nylon fabric made of 1050 denier, 168 filaments, 3 to 4 Z turns per inch...type 700 nylon yarn. These helmets liners satisfied the autoclave and the ballistics resistant requirements of Military Specification MIL-L-41800, Liner , Soldier’s Steel Helmet, 1 May 1961.

  2. T-Cap Pull-Off and Bending Behavior for Stitched Structure

    NASA Technical Reports Server (NTRS)

    Lovejoy, Andrew E.; Leone, Frank A., Jr.

    2016-01-01

    The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is a structural concept that was developed by The Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body aircraft configuration. An important design feature required for assembly is the integrally stitched T-cap, which provides connectivity of the corner (orthogonal) joint between adjacent panels. A series of tests were conducted on T-cap test articles, with and without a rod stiffener penetrating the T-cap web, under tension (pull-off) and bending loads. Three designs were tested, including the baseline design used in largescale test articles. The baseline had only the manufacturing stitch row adjacent to the fillet at the base of the T-cap web. Two new designs added stitching rows to the T-cap web at either 0.5- or 1.0-inch spacing along the height of the web. Testing was conducted at NASA Langley Research Center to determine the behavior of the T-cap region resulting from the applied loading. Results show that stitching arrests the initial delamination failures so that the maximum strength capability exceeds the load at which the initial delaminations develop. However, it was seen that the added web stitching had very little effect on the initial delamination failure load, but actually decreased the initial delamination failure load for tension loading of test articles without a stiffener passing through the web. Additionally, the added web stitching only increased the maximum load capability by between 1% and 12.5%. The presence of the stiffener, however, did increase the initial and maximum loads for both tension and bending loading as compared to the stringerless baseline design. Based on the results of the few samples tested, the additional stitching in the T-cap web showed little advantage over the baseline design in terms of structural failure at the T-cap web/skin junction for the current test articles.

  3. Simplified Habit Reversal Plus Adjunct Contingencies in the Treatment of Thumb Sucking and Hair Pulling in a Young Child.

    ERIC Educational Resources Information Center

    Long, Ethan S.; Miltenberger, Raymond G.; Rapp, John T.

    1999-01-01

    Using simplified reversal treatment consisting of awareness training, competing response training, and social support procedures, minimal results were initially obtained in thumb sucking and hair pulling behaviors. Additional treatment phases involving differential reinforcement and response cost resulted in near zero levels of the behavior when…

  4. Nano-yarn carbon nanotube fiber based enzymatic glucose biosensor

    NASA Astrophysics Data System (ADS)

    Zhu, Zhigang; Song, Wenhui; Burugapalli, Krishna; Moussy, Francis; Li, Ya-Li; Zhong, Xiao-Hua

    2010-04-01

    A novel brush-like electrode based on carbon nanotube (CNT) nano-yarn fiber has been designed for electrochemical biosensor applications and its efficacy as an enzymatic glucose biosensor demonstrated. The CNT nano-yarn fiber was spun directly from a chemical-vapor-deposition (CVD) gas flow reaction using a mixture of ethanol and acetone as the carbon source and an iron nano-catalyst. The fiber, 28 µm in diameter, was made of bundles of double walled CNTs (DWNTs) concentrically compacted into multiple layers forming a nano-porous network structure. Cyclic voltammetry study revealed a superior electrocatalytic activity for CNT fiber compared to the traditional Pt-Ir coil electrode. The electrode end tip of the CNT fiber was freeze-fractured to obtain a unique brush-like nano-structure resembling a scale-down electrical 'flex', where glucose oxidase (GOx) enzyme was immobilized using glutaraldehyde crosslinking in the presence of bovine serum albumin (BSA). An outer epoxy-polyurethane (EPU) layer was used as semi-permeable membrane. The sensor function was tested against a standard reference electrode. The sensitivities, linear detection range and linearity for detecting glucose for the miniature CNT fiber electrode were better than that reported for a Pt-Ir coil electrode. Thermal annealing of the CNT fiber at 250 °C for 30 min prior to fabrication of the sensor resulted in a 7.5 fold increase in glucose sensitivity. The as-spun CNT fiber based glucose biosensor was shown to be stable for up to 70 days. In addition, gold coating of the electrode connecting end of the CNT fiber resulted in extending the glucose detection limit to 25 µM. To conclude, superior efficiency of CNT fiber for glucose biosensing was demonstrated compared to a traditional Pt-Ir sensor.

  5. 29 CFR 1915.114 - Chain falls and pull-lifts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Chain falls and pull-lifts. 1915.114 Section 1915.114 Labor... and Materials Handling § 1915.114 Chain falls and pull-lifts. The provisions of this section shall apply to ship repairing, shipbuilding and shipbreaking. (a) Chain falls and pull-lifts shall be clearly...

  6. 29 CFR 1915.114 - Chain falls and pull-lifts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Chain falls and pull-lifts. 1915.114 Section 1915.114 Labor... and Materials Handling § 1915.114 Chain falls and pull-lifts. The provisions of this section shall apply to ship repairing, shipbuilding and shipbreaking. (a) Chain falls and pull-lifts shall be clearly...

  7. 29 CFR 1915.114 - Chain falls and pull-lifts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Chain falls and pull-lifts. 1915.114 Section 1915.114 Labor... and Materials Handling § 1915.114 Chain falls and pull-lifts. The provisions of this section shall apply to ship repairing, shipbuilding and shipbreaking. (a) Chain falls and pull-lifts shall be clearly...

  8. 29 CFR 1915.114 - Chain falls and pull-lifts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Chain falls and pull-lifts. 1915.114 Section 1915.114 Labor... and Materials Handling § 1915.114 Chain falls and pull-lifts. The provisions of this section shall apply to ship repairing, shipbuilding and shipbreaking. (a) Chain falls and pull-lifts shall be clearly...

  9. 29 CFR 1915.114 - Chain falls and pull-lifts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Chain falls and pull-lifts. 1915.114 Section 1915.114 Labor... and Materials Handling § 1915.114 Chain falls and pull-lifts. The provisions of this section shall apply to ship repairing, shipbuilding and shipbreaking. (a) Chain falls and pull-lifts shall be clearly...

  10. DC dynamic pull-in instability of a dielectric elastomer balloon: an energy-based approach

    NASA Astrophysics Data System (ADS)

    Sharma, Atul Kumar; Arora, Nitesh; Joglekar, M. M.

    2018-03-01

    This paper reports an energy-based method for the dynamic pull-in instability analysis of a spherical dielectric elastomer (DE) balloon subjected to a quasi-statically applied inflation pressure and a Heaviside step voltage across the balloon wall. The proposed technique relies on establishing the energy balance at the point of maximum stretch in an oscillation cycle, followed by the imposition of an instability condition for extracting the threshold parameters. The material models of the Ogden family are employed for describing the hyperelasticity of the balloon. The accuracy of the critical dynamic pull-in parameters is established by examining the saddle-node bifurcation in the transient response of the balloon obtained by integrating numerically the equation of motion, derived using the Euler-Lagrange equation. The parametric study brings out the effect of inflation pressure on the onset of the pull-in instability in the DE balloon. A quantitative comparison between the static and dynamic pull-in parameters at four different levels of the inflation pressure is presented. The results indicate that the dynamic pull-in instability gets triggered at electric fields that are lower than those corresponding to the static instability. The results of the present investigation can find potential use in the design and development of the balloon actuators subjected to transient loading. The method developed is versatile and can be used in the dynamic instability analysis of other conservative systems of interest.

  11. DC dynamic pull-in instability of a dielectric elastomer balloon: an energy-based approach.

    PubMed

    Sharma, Atul Kumar; Arora, Nitesh; Joglekar, M M

    2018-03-01

    This paper reports an energy-based method for the dynamic pull-in instability analysis of a spherical dielectric elastomer (DE) balloon subjected to a quasi-statically applied inflation pressure and a Heaviside step voltage across the balloon wall. The proposed technique relies on establishing the energy balance at the point of maximum stretch in an oscillation cycle, followed by the imposition of an instability condition for extracting the threshold parameters. The material models of the Ogden family are employed for describing the hyperelasticity of the balloon. The accuracy of the critical dynamic pull-in parameters is established by examining the saddle-node bifurcation in the transient response of the balloon obtained by integrating numerically the equation of motion, derived using the Euler-Lagrange equation. The parametric study brings out the effect of inflation pressure on the onset of the pull-in instability in the DE balloon. A quantitative comparison between the static and dynamic pull-in parameters at four different levels of the inflation pressure is presented. The results indicate that the dynamic pull-in instability gets triggered at electric fields that are lower than those corresponding to the static instability. The results of the present investigation can find potential use in the design and development of the balloon actuators subjected to transient loading. The method developed is versatile and can be used in the dynamic instability analysis of other conservative systems of interest.

  12. Common-pull, multiple-push, vacuum-activated telescope mirror cell.

    PubMed

    Ruiz, Elfego; Sohn, Erika; Salas, Luis; Luna, Esteban; Araiza-Durán, José A

    2014-11-20

    A new concept for push-pull active optics is presented, where the push-force is provided by means of individual airbag type actuators and a common force in the form of a vacuum is applied to the entire back of the mirror. The vacuum provides the pull-component of the system, in addition to gravity. Vacuum is controlled as a function of the zenithal angle, providing correction for the axial component of the mirror's weight. In this way, the push actuators are only responsible for correcting mirror deformations, as well as for supporting the axial mirror weight at the zenith, allowing for a uniform, full dynamic-range behavior of the system along the telescope's pointing range. This can result in the ability to perform corrections of up to a few microns for low-order aberrations. This mirror support concept was simulated using a finite element model and was tested experimentally at the 2.12 m San Pedro Mártir telescope. Advantages such as stress-free attachments, lighter weight, large actuator area, lower system complexity, and lower required mirror-cell stiffness could make this a method to consider for future large telescopes.

  13. Hair pull test: Evidence-based update and revision of guidelines.

    PubMed

    McDonald, Katherine A; Shelley, Amanda J; Colantonio, Sophia; Beecker, Jennifer

    2017-03-01

    The hair pull test lacks validation and has unclear pretest guidelines. We sought to quantify normal hair pull test values and elucidate the effect of pretest hair washing and brushing. The impact of hair texture and lifestyle was also examined. Participants (n = 181) completed a questionnaire recording demographics, medications, and hair health/history. A single hair pull test (scalp vertex) was performed. The mean number of hairs removed per pull was 0.44 (SD 0.75). There was no significant difference in the mean number of hairs removed regardless of when participants washed (P = .20) or brushed (P = .25) their hair. Hair pull test values were similar between Caucasian-, Asian-, and Afro-textured hair. There was no significant difference in hair pull values between participants taking medications affecting hair loss and participants not taking these medications (P = .33). Tight hairstyles did not influence hair pull test values. Participant hair washing and brushing could not be controlled during the study, but this information was documented and analyzed. Normal values for the hair pull test should be reduced to 2 hairs or fewer (97.2% of participants). The current 5-day restriction on pretest hair washing can be reduced and brushing be made permissible. Copyright © 2016 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  14. Psychophysical basis for maximum pushing and pulling forces: A review and recommendations.

    PubMed

    Garg, Arun; Waters, Thomas; Kapellusch, Jay; Karwowski, Waldemar

    2014-03-01

    The objective of this paper was to perform a comprehensive review of psychophysically determined maximum acceptable pushing and pulling forces. Factors affecting pushing and pulling forces are identified and discussed. Recent studies show a significant decrease (compared to previous studies) in maximum acceptable forces for males but not for females when pushing and pulling on a treadmill. A comparison of pushing and pulling forces measured using a high inertia cart with those measured on a treadmill shows that the pushing and pulling forces using high inertia cart are higher for males but are about the same for females. It is concluded that the recommendations of Snook and Ciriello (1991) for pushing and pulling forces are still valid and provide reasonable recommendations for ergonomics practitioners. Regression equations as a function of handle height, frequency of exertion and pushing/pulling distance are provided to estimate maximum initial and sustained forces for pushing and pulling acceptable to 75% male and female workers. At present it is not clear whether pushing or pulling should be favored. Similarly, it is not clear what handle heights would be optimal for pushing and pulling. Epidemiological studies are needed to determine relationships between psychophysically determined maximum acceptable pushing and pulling forces and risk of musculoskeletal injuries, in particular to low back and shoulders.

  15. Push-pull quinoidal porphyrins.

    PubMed

    Smith, Martin J; Blake, Iain M; Clegg, William; Anderson, Harry L

    2018-05-01

    A family of push-pull quinoidal porphyrin monomers has been prepared from a meso-formyl porphyrin by bromination, thioacetal formation, palladium-catalyzed coupling with malononitrile and oxidation with DDQ. Attempts at extending this synthesis to a push-pull quinoidal/cumulenic porphyrin dimer were not successful. The crystal structures of the quinoidal porphyrins indicate that there is no significant contribution from singlet biradical or zwitterionic resonance forms. The crystal structure of an ethyne-linked porphyrin dimer shows that the torsion angle between the porphyrin units is only about 3°, in keeping with crystallographic results on related compounds, but contrasting with the torsion angle of about 35° predicted by computational studies. The free-base quinoidal porphyrin monomers form tightly π-stacked layer structures, despite their curved geometries and bulky aryl substituents.

  16. Sexual behavior that is "out of control": a theoretical conceptual approach.

    PubMed

    Bancroft, John

    2008-12-01

    At this stage of our knowledge, it seems reasonable to assume that out-of-control sexual behavior results from a variety of etiological mechanisms associated with different behavioral patterns that share Goodman's two key features of addictive behavior: (1) a recurrent failure to control the sexual behavior; and (2) continuation of the behavior despite harmful consequences. Any overriding definition relevant to clinical management seems premature until we better understand the various patterns and their likely determinants. The concepts of "compulsivity" and "addiction" may have explanatory value in some cases, but are not helpful when used as general terms for this class of behavior problem. Stein and colleagues suggested that, in these circumstances, we use the term "hypersexuality." In my opinion, out-of-control sexual behavior or "impulse control disorders" as proposed by Barth and Kinder are more appropriate nonspecific terms because they focus on the issue of control rather than on high levels of sexuality. A number of clinically relevant and researchable hypotheses need to be addressed in further research, which hopefully will lead to more etiologically or therapeutically relevant subcategories of out-of-control sexual behavior.

  17. Centrifuge training program with "push-pull" elements.

    PubMed

    Mikuliszyn, Romuald; Zebrowski, Mariusz; Kowalczuk, Krzysztof

    2005-05-01

    Pilots of fighter aircraft are often exposed to maneuvers that produce negative acceleration (-Gz) immediately followed by positive acceleration (+Gz). This sequence has been found to reduce tolerance to +Gz, a phenomenon known as the "push-pull" effect. We devised a centrifuge training program to demonstrate this phenomenon to pilots. The centrifuge of the Military Institute of Aviation Medicine in Warsaw, Poland, was modified in 1996 to allow active positioning of the gondola during rotation. Head-down position of -6 degrees to -40 degrees were used to produce relative -Gz (r-Gz) in a range down to 0.2. As a side effect, this produces Gy acceleration between -1.3 Gy and -1.6 Gy. Pilots completed normal centrifuge training, including a relaxed, gradual-onset run and three rapid-onset runs. They were then exposed to a profile that included a series of push-pull exposures where r-Gz was followed by +Gz with stepwise increases in the latter from +2.5 to +5 Gz. The final profile was a simulated aerial combat maneuver with push-pull elements. The trainees expressed surprise at the push-pull effect, which forced them to begin an anti-G straining maneuver at lower levels than normal. They complained about the presence of the Gy, which rarely occurs in aircraft. This type of profile appears useful for training pilots about the push-pull phenomenon. After collection of additional data, the profiles may be refined.

  18. Carbon nanotube yarns for deep brain stimulation electrode.

    PubMed

    Jiang, Changqing; Li, Luming; Hao, Hongwei

    2011-12-01

    A new form of deep brain stimulation (DBS) electrode was proposed that was made of carbon nanotube yarns (CNTYs). Electrode interface properties were examined using cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS). The CNTY electrode interface exhibited large charge storage capacity (CSC) of 12.3 mC/cm(2) which increased to 98.6 mC/cm(2) after acid treatment, compared with 5.0 mC/cm(2) of Pt-Ir. Impedance spectrum of both untreated and treated CNTY electrodes showed that finite diffusion process occurred at the interface due to their porous structure and charge was delivered through capacitive mechanism. To evaluate stability electrical stimulus was exerted for up to 72 h and CV and EIS results of CNTY electrodes revealed little alteration. Therefore CNTY could make a good electrode material for DBS.

  19. Psychophysical basis for maximum pushing and pulling forces: A review and recommendations

    PubMed Central

    Garg, Arun; Waters, Thomas; Kapellusch, Jay; Karwowski, Waldemar

    2015-01-01

    The objective of this paper was to perform a comprehensive review of psychophysically determined maximum acceptable pushing and pulling forces. Factors affecting pushing and pulling forces are identified and discussed. Recent studies show a significant decrease (compared to previous studies) in maximum acceptable forces for males but not for females when pushing and pulling on a treadmill. A comparison of pushing and pulling forces measured using a high inertia cart with those measured on a treadmill shows that the pushing and pulling forces using high inertia cart are higher for males but are about the same for females. It is concluded that the recommendations of Snook and Ciriello (1991) for pushing and pulling forces are still valid and provide reasonable recommendations for ergonomics practitioners. Regression equations as a function of handle height, frequency of exertion and pushing/pulling distance are provided to estimate maximum initial and sustained forces for pushing and pulling acceptable to 75% male and female workers. At present it is not clear whether pushing or pulling should be favored. Similarly, it is not clear what handle heights would be optimal for pushing and pulling. Epidemiological studies are needed to determine relationships between psychophysically determined maximum acceptable pushing and pulling forces and risk of musculoskeletal injuries, in particular to low back and shoulders. PMID:26664045

  20. Poly(D,L-Lactide-Co-Glycolide) Tubes With Multifilament Chitosan Yarn or Chitosan Sponge Core in Nerve Regeneration.

    PubMed

    Wlaszczuk, Adam; Marcol, Wiesław; Kucharska, Magdalena; Wawro, Dariusz; Palen, Piotr; Lewin-Kowalik, Joanna

    2016-11-01

    The influence of different kinds of nerve guidance conduits on regeneration of totally transected rat sciatic nerves through a 7-mm gap was examined. Five different types of conduits made of chitosan and poly(D,L-lactide-co-glycolide) (PLGA) were constructed and tested in vivo. We divided 50 animals into equal groups of 10, with a different type of conduit implanted in each group: chitosan sponge core with an average molecular mass of polymer (Mv) of 287 kDa with 7 channels in a PLGA sleeve, chitosan sponge core with an Mv of 423 kDa with 7 channels in a PLGA sleeve, chitosan sponge core (Mv, 423 kDa) with 13 channels in a PLGA sleeve, chitosan multifilament yarn in a PLGA sleeve, and a PLGA sleeve only. Seven weeks after the operation, we examined the distance covered by regenerating nerve fibers, growing of nerves into the conduit's core, and intensity and type of inflammatory reaction in the conduit, as well as autotomy behavior (reflecting neuropathic pain intensity) in the animals. Two types of conduits were allowing nerve outgrowth through the gap with minor autotomy and minor inflammatory reactions. These were the conduits with chitosan multifilament yarn in a PLGA sleeve and the conduits with 13-channel microcrystalline chitosan sponge in a PLGA sleeve. The type of chitosan used to build the nerve guidance conduit influences the intensity and character of inflammatory reaction present during nerve regeneration, which in turn affects the distance crossed by regenerating nerve fibers, growing of the nerve fibers into the conduit's core, and the intensity of autotomy in the animals. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  1. Knowledge, Attitude, and Behaviors Related to Eating Out among University Students in China.

    PubMed

    Hu, Ping; Huang, Wenjie; Bai, Ruixue; Zhang, Fan; Sharma, Manoj; Shi, Zumin; Xiao, Xiaoqiu; Abdullah, Abu S; Zhao, Yong

    2016-07-12

    In many countries the frequency of eating out has steadily increased over the last few decades, and this behavioris often associated with unhealthy dietary patterns. This study aimed to describe the levels of knowledge, attitude, and behaviors (KAB) related to eating out among university students. A cross-sectional study was conducted in the college town in Chongqing, China with a total of 1634 participants. The mean eating out related KAB scores were: knowledge 11.5 ± 2.9, attitude 17.0 ± 2.8, and behaviors 24.2 ± 4.8 (possible total scores: 20, 24, 40 respectively). As the level of knowledge increased, the percentage of highly satisfactory attitude and behaviors increased. Only 10% of the participants did not eat out for lunch and dinner during weekends in the last month. Gender, ethnicity, mother's education, monthly boarding expenses, living place during the study, and the frequency of eating out for breakfast were statistically associated with the scores of KAB. In conclusion, Chinese junior students had poor knowledge of and behaviors towards eating out and ate out frequently. Educational interventionsto improve knowledge related eating out are needed in order to promote healthy eating out behaviors among Chinese university students.

  2. Trichotillomania (hair pulling disorder), skin picking disorder, and stereotypic movement disorder: toward DSM-V.

    PubMed

    Stein, Dan J; Grant, Jon E; Franklin, Martin E; Keuthen, Nancy; Lochner, Christine; Singer, Harvey S; Woods, Douglas W

    2010-06-01

    In DSM-IV-TR, trichotillomania (TTM) is classified as an impulse control disorder (not classified elsewhere), skin picking lacks its own diagnostic category (but might be diagnosed as an impulse control disorder not otherwise specified), and stereotypic movement disorder is classified as a disorder usually first diagnosed in infancy, childhood, or adolescence. ICD-10 classifies TTM as a habit and impulse disorder, and includes stereotyped movement disorders in a section on other behavioral and emotional disorders with onset usually occurring in childhood and adolescence. This article provides a focused review of nosological issues relevant to DSM-V, given recent empirical findings. This review presents a number of options and preliminary recommendations to be considered for DSM-V: (1) Although TTM fits optimally into a category of body-focused repetitive behavioral disorders, in a nosology comprised of relatively few major categories it fits best within a category of motoric obsessive-compulsive spectrum disorders, (2) available evidence does not support continuing to include (current) diagnostic criteria B and C for TTM in DSM-V, (3) the text for TTM should be updated to describe subtypes and forms of hair pulling, (4) there are persuasive reasons for referring to TTM as "hair pulling disorder (trichotillomania)," (5) diagnostic criteria for skin picking disorder should be included in DSM-V or in DSM-Vs Appendix of Criteria Sets Provided for Further Study, and (6) the diagnostic criteria for stereotypic movement disorder should be clarified and simplified, bringing them in line with those for hair pulling and skin picking disorder. (c) 2010 Wiley-Liss, Inc.

  3. Photoinduced intramolecular charge transfer in a cross-conjugated push-pull enediyne: implications toward photoreaction.

    PubMed

    Singh, Anuja; Pati, Avik Kumar; Mishra, Ashok Kumar

    2018-05-30

    Push-pull organic fluorophores are important owing to their interesting optoelectronical properties. Here we report the photophysics of a new cross-conjugated push-pull enediynyl dye which belongs to an unexplored class of π-conjugated donor-acceptor systems. Two N,N-dimethylaniline moieties serve as donors and one pyrene ring functions as an acceptor via a common Y-shaped 'enediyne' bridge which facilitates the cross-electronic communication. The dye exhibits dual emission from locally excited (LE) and intramolecular charge transfer (ICT) states. While the LE emission is dominant in non-polar solvents, the ICT emission predominates in polar solvents. Time-resolved fluorescence decay experiments reveal a relatively shorter lifetime component (∼0.5-0.9 ns) belonging to an ICT state and a relatively longer lifetime species (∼1.6-2.8 ns) corresponding to the LE state. The strong ICT behavior of the dye is manifested through the huge red-shift (4166 cm-1) of the emission spectra from non-polar cyclohexane to polar N,N-dimethylformamide. In contrast to many small push-pull organic dyes, the LE and ICT states of the push-pull enediynyl dye follow the same excitation pathway. The dominant red-shifted ICT emission (∼550 nm) intensity of the dye in polar solvent decreases with a concomitant appearance of the blue-shifted LE emission (∼385 nm) upon prolonged exposure to photons. This opens up a new photophysical strategy of achieving high contrast two fluorescence color conversion from yellow to blue.

  4. 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.

  5. Enhanced Basicity of Push-Pull Nitrogen Bases in the Gas Phase.

    PubMed

    Raczyńska, Ewa D; Gal, Jean-François; Maria, Pierre-Charles

    2016-11-23

    Nitrogen bases containing one or more pushing amino-group(s) directly linked to a pulling cyano, imino, or phosphoimino group, as well as those in which the pushing and pulling moieties are separated by a conjugated spacer (C═X) n , where X is CH or N, display an exceptionally strong basicity. The n-π conjugation between the pushing and pulling groups in such systems lowers the basicity of the pushing amino-group(s) and increases the basicity of the pulling cyano, imino, or phosphoimino group. In the gas phase, most of the so-called push-pull nitrogen bases exhibit a very high basicity. This paper presents an analysis of the exceptional gas-phase basicity, mostly in terms of experimental data, in relation with structure and conjugation of various subfamilies of push-pull nitrogen bases: nitriles, azoles, azines, amidines, guanidines, vinamidines, biguanides, and phosphazenes. The strong basicity of biomolecules containing a push-pull nitrogen substructure, such as bioamines, amino acids, and peptides containing push-pull side chains, nucleobases, and their nucleosides and nucleotides, is also analyzed. Progress and perspectives of experimental determinations of GBs and PAs of highly basic compounds, termed as "superbases", are presented and benchmarked on the basis of theoretical calculations on existing or hypothetical molecules.

  6. Biomechanical comparison between suture anchor and transtibial pull-out repair for posterior medial meniscus root tears.

    PubMed

    Feucht, Matthias J; Grande, Eduardo; Brunhuber, Johannes; Rosenstiel, Nikolaus; Burgkart, Rainer; Imhoff, Andreas B; Braun, Sepp

    2014-01-01

    Posterior medial meniscus root (PMMR) tears have a serious effect on knee joint biomechanics. Currently used techniques for refixation of the PMMR include the transtibial pull-out repair (TP) and suture anchor repair (SA). These techniques have not been compared biomechanically. The SA technique provides superior biomechanical properties compared with the TP technique. Controlled laboratory study. A total of 24 fresh-frozen porcine tibiae with attached intact medial menisci were used. The specimens were randomly assigned to 3 groups (8 specimens each). A standardized PMMR tear was created in 16 specimens. Refixation of the PMMR was performed by either the TP or SA technique. The native PMMR was left intact in 8 specimens. All specimens were subjected to cyclic loading followed by load-to-failure testing. Displacement after 100, 500, and 1000 cycles; maximum load to failure; stiffness; and displacement at failure were recorded. Both repair techniques showed a significantly higher displacement during cyclic loading and a significantly lower maximum load and stiffness during load-to-failure testing compared with the native PMMR (P < .05). The SA technique showed a significantly lower displacement after 100, 500, and 1000 cycles (P < .001) and a significantly higher stiffness (P = .016) compared with the TP technique. Maximum load did not differ significantly between the SA and TP techniques (P = .027, Bonferroni adjustment). No significant difference between the 3 groups was observed for displacement at failure (P > .05). The SA technique provided superior biomechanical properties compared with the TP technique. Both repair techniques did not reach the strength of the native PMMR. The favorable biomechanical properties of the SA technique might be beneficial for healing of the repaired PMMR and restoration of meniscus function. Because of inferior time zero stability compared with the native PMMR, slow rehabilitation is recommended after meniscus root repair.

  7. Knowledge, Attitude, and Behaviors Related to Eating Out among University Students in China

    PubMed Central

    Hu, Ping; Huang, Wenjie; Bai, Ruixue; Zhang, Fan; Sharma, Manoj; Shi, Zumin; Xiao, Xiaoqiu; Abdullah, Abu S.; Zhao, Yong

    2016-01-01

    In many countries the frequency of eating out has steadily increased over the last few decades, and this behavioris often associated with unhealthy dietary patterns. This study aimed to describe the levels of knowledge, attitude, and behaviors (KAB) related to eating out among university students. A cross-sectional study was conducted in the college town in Chongqing, China with a total of 1634 participants. The mean eating out related KAB scores were: knowledge 11.5 ± 2.9, attitude 17.0 ± 2.8, and behaviors 24.2 ± 4.8 (possible total scores: 20, 24, 40 respectively). As the level of knowledge increased, the percentage of highly satisfactory attitude and behaviors increased. Only 10% of the participants did not eat out for lunch and dinner during weekends in the last month. Gender, ethnicity, mother’s education, monthly boarding expenses, living place during the study, and the frequency of eating out for breakfast were statistically associated with the scores of KAB. In conclusion, Chinese junior students had poor knowledge of and behaviors towards eating out and ate out frequently. Educational interventionsto improve knowledge related eating out are needed in order to promote healthy eating out behaviors among Chinese university students. PMID:27420075

  8. Accurate electrostatic and van der Waals pull-in prediction for fully clamped nano/micro-beams using linear universal graphs of pull-in instability

    NASA Astrophysics Data System (ADS)

    Tahani, Masoud; Askari, Amir R.

    2014-09-01

    In spite of the fact that pull-in instability of electrically actuated nano/micro-beams has been investigated by many researchers to date, no explicit formula has been presented yet which can predict pull-in voltage based on a geometrically non-linear and distributed parameter model. The objective of present paper is to introduce a simple and accurate formula to predict this value for a fully clamped electrostatically actuated nano/micro-beam. To this end, a non-linear Euler-Bernoulli beam model is employed, which accounts for the axial residual stress, geometric non-linearity of mid-plane stretching, distributed electrostatic force and the van der Waals (vdW) attraction. The non-linear boundary value governing equation of equilibrium is non-dimensionalized and solved iteratively through single-term Galerkin based reduced order model (ROM). The solutions are validated thorough direct comparison with experimental and other existing results reported in previous studies. Pull-in instability under electrical and vdW loads are also investigated using universal graphs. Based on the results of these graphs, non-dimensional pull-in and vdW parameters, which are defined in the text, vary linearly versus the other dimensionless parameters of the problem. Using this fact, some linear equations are presented to predict pull-in voltage, the maximum allowable length, the so-called detachment length, and the minimum allowable gap for a nano/micro-system. These linear equations are also reduced to a couple of universal pull-in formulas for systems with small initial gap. The accuracy of the universal pull-in formulas are also validated by comparing its results with available experimental and some previous geometric linear and closed-form findings published in the literature.

  9. Pushing, pulling and manoeuvring an industrial cart: a psychophysiological study.

    PubMed

    Giagloglou, Evanthia; Radenkovic, Milan; Brankovic, Sasa; Antoniou, Panagiotis; Zivanovic-Macuzic, Ivana

    2017-09-18

    One of the most frequent manual occupational tasks involves the pushing and pulling of a cart. Although several studies have associated health risks with pushing and pulling, the effects are not clear since occupational tasks have social, cognitive and physical components. The present work investigates a real case of a pushing and pulling occupational task from a manufacturing company. The study initially characterizes the case in accordance with Standard No. ISO 11228-2:2007 as low risk. An experiment with 14 individuals during three modalities of pushing and pulling was performed in order to further investigate the task with the application of electrophysiology. At the end, a simple questionnaire was given. The results show electrophysiological differences among the three modalities of pushing and pulling, with a major difference between action with no load and fully loaded with a full range of motions on the cart to handle.

  10. 19 CFR 10.543 - Certain apparel goods made from fabric or yarn not available in commercial quantities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... RATE, ETC. United States-Singapore Free Trade Agreement Rules of Origin § 10.543 Certain apparel goods... both of the Parties from fabric or yarn, regardless of origin, designated by the Committee for the... FR 17412), May 28, 2002 (67 FR 36858), and September 5, 2002 (67 FR 56806). Origin Verifications and...

  11. Design of Novel Wearable, Stretchable, and Waterproof Cable-Type Supercapacitors Based on High-Performance Nickel Cobalt Sulfide-Coated Etching-Annealed Yarn Electrodes.

    PubMed

    Chen, Yuejiao; Xu, Bingang; Wen, Jianfeng; Gong, Jianliang; Hua, Tao; Kan, Chi-Wai; Deng, Jiwei

    2018-04-19

    Rapid advances in functional electronics bring tremendous demands on innovation toward effective designs of device structures. Yarn supercapacitors (SCs) show advantages of flexibility, knittability, and small size, and can be integrated into various electronic devices with low cost and high efficiency for energy storage. In this work, functionalized stainless steel yarns are developed to support active materials of positive and negative electrodes, which not only enhance capacitance of both electrodes but can also be designed into stretchable configurations. The as-made asymmetric yarn SCs show a high energy density of 0.0487 mWh cm -2 (10.19 mWh cm -3 ) at a power density of 0.553 mW cm -2 (129.1 mW cm -3 ) and a specific capacitance of 127.2 mF cm -2 under an operating voltage window of 1.7 V. The fabricated SC is then made into a stretchable configuration by a prestraining-then-releasing approach using polydimethylsiloxane (PDMS) tube, and its electrochemical performance can be well maintained when stretching up to a high strain of 100%. Moreover, the stretchable cable-type SCs are stably workable under water-immersed condition. The method opens up new ways for fabricating flexible, stretchable, and waterproof devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Friction pull plug welding: top hat plug design

    NASA Technical Reports Server (NTRS)

    Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

    2001-01-01

    Friction Pull Plug Welding is a solid state repair process for defects up to one inch in length, only requiring single sided tooling, or outside skin line (OSL), for preferred usage on flight hardware. The most prevalent defect associated with Friction Pull Plug Welding (FPPW) was a top side or inside skin line (ISL) lack of bonding. Bonding was not achieved at this location due to the reduction in both frictional heat and welding pressure between the plug and plate at the end of the weld. Thus, in order to eliminate the weld defects and increase the plug strength at the plug `top` a small `hat` section is added to the pull plug for added frictional heating and pressure.

  13. Friction pull plug welding: top hat plug design

    NASA Technical Reports Server (NTRS)

    Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

    2002-01-01

    Friction Pull Plug Welding is a solid state repair process for defects up to one inch in length, only requiring single sided tooling, or outside skin line (OSL), for preferred usage on flight hardware. The most prevalent defect associated with Friction Pull Plug Welding (FPPW) was a top side or inside skin line (ISL) lack of bonding. Bonding was not achieved at this location due to the reduction in both frictional heat and welding pressure between the plug and plate at the end of the weld. Thus, in order to eliminate the weld defects and increase the plug strength at the plug `top` a small `hat` section is added to the pull plug for added frictional heating and pressure.

  14. Why Clothes Don't Fall Apart: Tension Transmission in Staple Yarns

    NASA Astrophysics Data System (ADS)

    Warren, Patrick B.; Ball, Robin C.; Goldstein, Raymond E.

    2018-04-01

    The problem of how staple yarns transmit tension is addressed within abstract models in which the Amontons-Coulomb friction laws yield a linear programing (LP) problem for the tensions in the fiber elements. We find there is a percolation transition such that above the percolation threshold the transmitted tension is in principle unbounded. We determine that the mean slack in the LP constraints is a suitable order parameter to characterize this supercritical state. We argue the mechanism is generic, and in practical terms, it corresponds to a switch from a ductile to a brittle failure mode accompanied by a significant increase in mechanical strength.

  15. Initial atomic coherences and Ramsey frequency pulling in fountain clocks

    NASA Astrophysics Data System (ADS)

    Gerginov, Vladislav; Nemitz, Nils; Weyers, Stefan

    2014-09-01

    In the uncertainty budget of primary atomic cesium fountain clocks, evaluations of frequency-pulling shifts of the hyperfine clock transition caused by unintentional excitation of its nearby transitions (Rabi and Ramsey pulling) have been based so far on an approach developed for cesium beam clocks. We re-evaluate this type of frequency pulling in fountain clocks and pay particular attention to the effect of initial coherent atomic states. We find significantly enhanced frequency shifts caused by Ramsey pulling due to sublevel population imbalance and corresponding coherences within the state-selected hyperfine component of the initial atom ground state. Such shifts are experimentally investigated in an atomic fountain clock and quantitative agreement with the predictions of the model is demonstrated.

  16. INTERSESSION RELIABILITY OF UPPER EXTREMITY ISOKINETIC PUSH-PULL TESTING.

    PubMed

    Riemann, Bryan L; Davis, Sarah E; Huet, Kevin; Davies, George J

    2016-02-01

    Based on the frequency pushing and pulling patterns are used in functional activities, there is a need to establish an objective method of quantifying the muscle performance characteristics associated with these motions, particularly during the later stages of rehabilitation as criteria for discharge. While isokinetic assessment offers an approach to quantifying muscle performance, little is known about closed kinetic chain (CKC) isokinetic testing of the upper extremity (UE). To determine the intersession reliability of isokinetic upper extremity measurement of pushing and pulling peak force and average power at slow (0.24 m/s), medium (0.43 m/s) and fast (0.61 m/s) velocities in healthy young adults. The secondary purpose was to compare pushing and pulling peak force (PF) and average power (AP) between the upper extremity limbs (dominant, non-dominant) across the three velocities. Twenty-four physically active men and women completed a test-retest (>96 hours) protocol in order to establish isokinetic UE CKC reliability of PF and AP during five maximal push and pull repetitions at three velocities. Both limb and speed orders were randomized between subjects. High test-retest relative reliability using intraclass correlation coefficients (ICC2, 1) were revealed for PF (.91-.97) and AP (.85-.95) across velocities, limbs and directions. PF typical error (% coefficient of variation) ranged from 6.1% to 11.3% while AP ranged from 9.9% to 26.7%. PF decreased significantly (p < .05) as velocity increased whereas AP increased as velocity increased. PF and AP during pushing were significantly greater than pulling at all velocities, however the push-pull differences in PF became less as velocity increased. There were no significant differences identified between the dominant and nondominant limbs. Isokinetically derived UE CKC push-pull PF and AP are reliable measures. The lack of limb differences in healthy normal participants suggests that clinicians can

  17. Preparation (pulling) of needles for gene delivery by microinjection.

    PubMed

    Dean, David A

    2006-12-01

    INTRODUCTIONThis protocol contains methods for pulling microinjection needles using two different models of pipette pullers. The advantage of pulling needles in the laboratory is that a variety of different needle types can be pulled, depending on the samples and cells being injected. An added advantage is cost; once a pipette puller has been purchased, boxes of glass capillaries are inexpensive compared to premade microinjection needles. The advantages to buying preformed and sterilized needles include increased uniformity of needles from one to another, ease of use, high quality, and not having to invest in a pipette puller. The pipette puller models described in this article are the Flaming/Brown Pipette Puller Model P-97 (Sutter) and the PUL-1 Micropipette Puller (World Precision Instruments). The PUL-1 instrument is the less expensive of the two, but it requires more user input, and it cannot be used to pull Femtotip-like microinjection pipettes.

  18. Are pushing and pulling work-related risk factors for upper extremity symptoms? A systematic review of observational studies.

    PubMed

    Hoozemans, M J M; Knelange, E B; Frings-Dresen, M H W; Veeger, H E J; Kuijer, P P F M

    2014-11-01

    Systematically review observational studies concerning the question whether workers that perform pushing/pulling activities have an increased risk for upper extremity symptoms as compared to workers that perform no pushing/pulling activities. A search in MEDLINE via PubMed and EMBASE was performed with work-related search terms combined with push/pushing/pull/pulling. Studies had to examine exposure to pushing/pulling in relation to upper extremity symptoms. Two authors performed the literature selection and assessment of the risk of bias in the studies independently. A best evidence synthesis was used to draw conclusions in terms of strong, moderate or conflicting/insufficient evidence. The search resulted in 4764 studies. Seven studies were included, with three of them of low risk of bias, in total including 8279 participants. A positive significant relationship with upper extremity symptoms was observed in all four prospective cohort studies with effect sizes varying between 1.5 and 4.9. Two out of the three remaining studies also reported a positive association with upper extremity symptoms. In addition, significant positive associations with neck/shoulder symptoms were found in two prospective cohort studies with effect sizes of 1.5 and 1.6, and with shoulder symptoms in one of two cross-sectional studies with an effect size of 2.1. There is strong evidence that pushing/pulling is related to upper extremity symptoms, specifically for shoulder symptoms. There is insufficient or conflicting evidence that pushing/pulling is related to (combinations of) upper arm, elbow, forearm, wrist or hand symptoms. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  19. Haul-Out Behavior of Harbor Seals (Phoca vitulina) in Hood Canal, Washington

    PubMed Central

    London, Josh M.; Ver Hoef, Jay M.; Jeffries, Steven J.; Lance, Monique M.; Boveng, Peter L.

    2012-01-01

    The goal of this study was to model haul-out behavior of harbor seals (Phoca vitulina) in the Hood Canal region of Washington State with respect to changes in physiological, environmental, and temporal covariates. Previous research has provided a solid understanding of seal haul-out behavior. Here, we expand on that work using a generalized linear mixed model (GLMM) with temporal autocorrelation and a large dataset. Our dataset included behavioral haul-out records from archival and VHF radio tag deployments on 25 individual seals representing 61,430 seal hours. A novel application for increased computational efficiency allowed us to examine this large dataset with a GLMM that appropriately accounts for temporal autocorellation. We found significant relationships with the covariates hour of day, day of year, minutes from high tide and year. Additionally, there was a significant effect of the interaction term hour of day : day of year. This interaction term demonstrated that seals are more likely to haul out during nighttime hours in August and September, but then switch to predominantly daylight haul-out patterns in October and November. We attribute this change in behavior to an effect of human disturbance levels. This study also examined a unique ecological event to determine the role of increased killer whale (Orcinus orca) predation on haul-out behavior. In 2003 and 2005 these harbor seals were exposed to unprecedented levels of killer whale predation and results show an overall increase in haul-out probability after exposure to killer whales. The outcome of this study will be integral to understanding any changes in population abundance as a result of increased killer whale predation. PMID:22723851

  20. Modeling of the fracture behavior of spot welds using advanced micro-mechanical damage models

    NASA Astrophysics Data System (ADS)

    Sommer, Silke

    2010-06-01

    This paper presents the modeling of deformation and fracture behavior of resistance spot welded joints in DP600 steel sheets. Spot welding is still the most commonly used joining technique in automotive engineering. In overloading situations like crash joints are often the weakest link in a structure. For those reasons, crash simulations need reliable and applicable tools to predict the load bearing capacity of spot welded components. Two series of component tests with different spot weld diameters have shown that the diameter of the weld nugget is the main influencing factor affecting fracture mode (interfacial or pull-out fracture), load bearing capacity and energy absorption. In order to find a correlation between nugget diameter, load bearing capacity and fracture mode, the spot welds are simulated with detailed finite element models containing base metal, heat affected zone and weld metal in lap-shear loading conditions. The change in fracture mode from interfacial to pull-out or peel-out fracture with growing nugget diameter under lap-shear loading was successfully modeled using the Gologanu-Leblond model in combination with the fracture criteria of Thomason and Embury. A small nugget diameter is identified to be the main cause for interfacial fracture. In good agreement with experimental observations, the calculated pull-out fracture initiates in the base metal at the boundary to the heat affected zone.

  1. Living nanofiber yarn-based woven biotextiles for tendon tissue engineering using cell tri-culture and mechanical stimulation.

    PubMed

    Wu, Shaohua; Wang, Ying; Streubel, Philipp N; Duan, Bin

    2017-10-15

    Non-woven nanofibrous scaffolds have been developed for tendon graft application by using electrospinning strategies. However, electrospun nanofibrous scaffolds face some obstacles and limitations, including suboptimal scaffold structure, weak tensile and suture-retention strengths, and compact structure for cell infiltration. In this work, a novel nanofibrous, woven biotextile, fabricated based on electrospun nanofiber yarns, was implemented as a tissue engineered tendon scaffold. Based on our modified electrospinning setup, polycaprolactone (PCL) nanofiber yarns were fabricated with reproducible quality, and were further processed into plain-weaving fabrics interlaced with polylactic acid (PLA) multifilaments. Nonwoven nanofibrous PCL meshes with random or aligned fiber structures were generated using typical electrospinning as comparative counterparts. The woven fabrics contained 3D aligned microstructures with significantly larger pore size and obviously enhanced tensile mechanical properties than their nonwoven counterparts. The biological results revealed that cell proliferation and infiltration, along with the expression of tendon-specific genes by human adipose derived mesenchymal stem cells (HADMSC) and human tenocytes (HT), were significantly enhanced on the woven fabrics compared with those on randomly-oriented or aligned nanofiber meshes. Co-cultures of HADMSC with HT or human umbilical vein endothelial cells (HUVEC) on woven fabrics significantly upregulated the functional expression of most tenogenic markers. HADMSC/HT/HUVEC tri-culture on woven fabrics showed the highest upregulation of most tendon-associated markers than all the other mono- and co-culture groups. Furthermore, we conditioned the tri-cultured constructs with dynamic conditioning and demonstrated that dynamic stretch promoted total collagen secretion and tenogenic differentiation. Our nanofiber yarn-based biotextiles have significant potential to be used as engineered scaffolds to

  2. The "Push-Pull" Approach to Fast-Track Management Development: A Case Study in Scientific Publishing

    ERIC Educational Resources Information Center

    Fojt, Martin; Parkinson, Stephen; Peters, John; Sandelands, Eric

    2008-01-01

    Purpose: The purpose of this paper is to explore how a medium sized business has addressed what it has termed a "push-pull" method of management and organization development, based around an action learning approach. Design/methodology/approach: The paper sets out a methodology that other SMEs might look to replicate in their management and…

  3. Test and Analysis of Composite Hat Stringer Pull-off Test Specimens

    NASA Technical Reports Server (NTRS)

    Li, Jian; OBrien, T. Kevin; Rousseau, Carl Q.

    1996-01-01

    Hat stringer pull-off tests were performed to evaluate the delamination failure mechanisms in the flange region for a rod-reinforced hat stringer section. A special test fixture was used to pull the hat off the stringer while reacting the pull-off load through roller supports at both stringer flanges. Microscopic examinations of the failed specimens revealed that failure occurred at the ply termination in the flange area where the flange of the stiffener is built up by adding 45/-45 tape plies on the top surface. Test results indicated that the as-manufactured microstructure in the flange region has a strong influence on the delamination initiation and the associated pull-off loads. Finite element models were created for each specimen with a detailed mesh based on micrographs of the critical location. A fracture mechanics approach and a mixed mode delamination criterion were used to predict the onset of delamination and the pull-off load. By modeling the critical local details of each specimen from micrographs, the model was able to accurately predict the hat stringer pull-off loads and replicate the variability in the test results.

  4. Children with Behavioral, Non-Behavioral, and Multiple Disabilities, and the Risk of Out-of-Home Placement Disruption

    ERIC Educational Resources Information Center

    Helton, Jesse J.

    2011-01-01

    Objective: This study examined the relative risk of placement disruption for 3-10 year-old children placed in out-of-home care based on the biological relatedness of the placement caregiver and child disability status: no disability, a non-behavioral disability only, a behavioral disability only, or both a non-behavioral and behavioral disability.…

  5. Low temperature-pressure batch experiments and field push-pull tests: Assessing potential effects of an unintended CO2 release from CCUS projects on groundwater chemistry

    NASA Astrophysics Data System (ADS)

    Mickler, P. J.; Yang, C.; Lu, J.; Reedy, R. C.; Scanlon, B. R.

    2012-12-01

    Carbon Capture Utilization and Storage projects (CCUS), where CO2 is captured at point sources such as power stations and compressed into a supercritical liquid for underground storage, has been proposed to reduce atmospheric CO2 and mitigate global climate change. Problems may arise from CO2 releases along discreet pathways such as abandoned wells and faults, upwards and into near surface groundwater. Migrating CO2 may inversely impact fresh water resources by increasing mineral solubility and dissolution rates and mobilizing harmful trace elements including As and Pb. This study addresses the impacts on fresh water resources through a combination of laboratory batch experiments, where aquifer sediment are reacted in their corresponding groundwater in 100% CO2 environments, and field push-pull tests where groundwater is equilibrated with 100% CO2, reacted in-situ in the groundwater system, and pulled out for analyses. Batch experiments were performed on aquifer material from carbonate dominated, mixed carbonate/silicalstic, and siliclastic dominated systems. A mixed silicalstic/carbonate system was chosen for the field based push-pull test. Batch experiment results suggest carbonate dissolution increased the concentration of Ca, Mg, Sr, Ba, Mn, U and HCO3- in groundwater. In systems with significant carbonate content, dissolution continued until carbonate saturation was achieved at approximately 1000 hr. Silicate dissolution increased the conc. of Si, K Ni and Co, but at much lower rates than carbonate dissolution. The elements As, Mo, V, Zn, Se and Cd generally show similar behavior where concentrations initially increase but soon drop to levels at or below the background concentrations (~48 hours). A Push-Pull test on one aquifer system produced similar geochemical behavior but observed reaction rates are higher in batch experiments relative to push-pull tests. Release of CO2 from CCUS sites into overlying aquifer systems may adversely impact groundwater quality

  6. Dynamic push-pull characteristics at three hand-reach envelopes: applications for the workplace.

    PubMed

    Calé-Benzoor, Maya; Dickstein, Ruth; Arnon, Michal; Ayalon, Moshe

    2016-01-01

    Pushing and pulling are common tasks in the workplace. Overexertion injuries related to manual pushing and pulling are often observed, and therefore the understanding of work capacity is important for efficient and safe workstation design. The purpose of the present study was to describe workloads obtained during different reach envelopes during a seated push-pull task. Forty-five women performed an isokinetic push-pull sequence at two velocities. Strength, work and agonist/antagonist muscle ratio were calculated for the full range of motion (ROM). We then divided the ROM into three reach envelopes - neutral, medium, and maximum reach. The work capacity for each direction was determined and the reach envelope work data were compared. Push capability was best at medium reach envelope and pulling was best at maximum reach envelope. Push/pull strength ratio was approximately 1. A recommendation was made to avoid strenuous push-pull tasks at neutral reach envelopes. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  7. Individual and institutional push and pull factors as predictors of retirement timing in Europe: A multilevel analysis.

    PubMed

    De Preter, Hanne; Van Looy, Dorien; Mortelmans, Dimitri

    2013-12-01

    The number of retired people in Europe has increased significantly in recent decades. It remains unclear, however, whether individuals are more likely to be pulled toward retirement by their expectations about life after retirement than they are to be pushed out of the labour market due to poor health or dislike of one's job. The fact that retirement timing differs rather considerably between European countries suggests that not only micro, but also macro push (i.e. labour market constraints) and pull (i.e. economic incentives) factors influence retirement decisions. This duality heightens the need to determine the influence of micro-level and macro-level push and pull indicators on the retirement timing of older workers (50+) in Europe. Results are obtained performing multilevel event history analysis using longitudinal micro data from the first (2004/05) and second (2006/07) waves of the Survey of Health, Ageing and Retirement in Europe and macro data derived from the Organisation for Economic Cooperation and Development (OECD) and Eurostat. The results indicate that at the individual level, older workers are pushed out due to health problems as well as being attracted towards retirement to spend time with their grandchildren. At the institutional level, financial incentives such as a high implicit tax on continued work and high expenditures on early exit schemes make retirement attractive, whereas the institutional push context is of lesser importance. © 2013.

  8. The push and pull of grief: Approach and avoidance in bereavement.

    PubMed

    Maccallum, Fiona; Sawday, Simon; Rinck, Mike; Bryant, Richard A

    2015-09-01

    Prolonged Grief (PG) is recognized as a post-bereavement syndrome that is associated with significant impairment. Although approach and avoidance tendencies have both been hypothesized to play key roles in maintaining PG symptoms, understanding of these relationships has been limited by a reliance on self-report methodology. This study applies an experimental paradigm to simultaneously investigate the relationship between PG severity and approach-avoidance behavioral tendencies. Fifty-five bereaved individuals with and without PG completed a behavioral measure of approach and avoidance responding in which they pulled or pushed a joystick in response to grief-related, positive, negative and neutral images that appeared on a computer screen. Concurrent visual feedback created the illusion that the images were either approaching or receding from the participant. Half of the participants also received a prime designed to activate their grief prior to the task. Irrespective of prime condition, PG participants pulled grief-related images more quickly than they pushed them. This difference was not observed in response to non-grief related images. Non PG participants showed no difference in their reaction times to grief-stimuli. This study was undertaken in a nonclinical setting and the majority of participants had lost a loved one due to chronic illness. Future research with treatment-seeking populations and sudden loss will be needed to explore the generalizability of the findings. The findings from this study provide preliminary evidence supporting models of PG that integrate approach and avoidance tendencies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Coupling detrended fluctuation analysis for multiple warehouse-out behavioral sequences

    NASA Astrophysics Data System (ADS)

    Yao, Can-Zhong; Lin, Ji-Nan; Zheng, Xu-Zhou

    2017-01-01

    Interaction patterns among different warehouses could make the warehouse-out behavioral sequences less predictable. We firstly take a coupling detrended fluctuation analysis on the warehouse-out quantity, and find that the multivariate sequences exhibit significant coupling multifractal characteristics regardless of the types of steel products. Secondly, we track the sources of multifractal warehouse-out sequences by shuffling and surrogating original ones, and we find that fat-tail distribution contributes more to multifractal features than the long-term memory, regardless of types of steel products. From perspective of warehouse contribution, some warehouses steadily contribute more to multifractal than other warehouses. Finally, based on multiscale multifractal analysis, we propose Hurst surface structure to investigate coupling multifractal, and show that multiple behavioral sequences exhibit significant coupling multifractal features that emerge and usually be restricted within relatively greater time scale interval.

  10. A push-pull system to reduce house entry of malaria mosquitoes

    PubMed Central

    2014-01-01

    Background Mosquitoes are the dominant vectors of pathogens that cause infectious diseases such as malaria, dengue, yellow fever and filariasis. Current vector control strategies often rely on the use of pyrethroids against which mosquitoes are increasingly developing resistance. Here, a push-pull system is presented, that operates by the simultaneous use of repellent and attractive volatile odorants. Method/Results Experiments were carried out in a semi-field set-up: a traditional house which was constructed inside a screenhouse. The release of different repellent compounds, para-menthane-3,8-diol (PMD), catnip oil e.o. and delta-undecalactone, from the four corners of the house resulted in significant reductions of 45% to 81.5% in house entry of host-seeking malaria mosquitoes. The highest reductions in house entry (up to 95.5%), were achieved by simultaneously repelling mosquitoes from the house (push) and removing them from the experimental set-up using attractant-baited traps (pull). Conclusions The outcome of this study suggests that a push-pull system based on attractive and repellent volatiles may successfully be employed to target mosquito vectors of human disease. Reductions in house entry of malaria vectors, of the magnitude that was achieved in these experiments, would likely affect malaria transmission. The repellents used are non-toxic and can be used safely in a human environment. Delta-undecalactone is a novel repellent that showed higher effectiveness than the established repellent PMD. These results encourage further development of the system for practical implementation in the field. PMID:24674451

  11. Push-me-pull-you: how microtubules organize the cell interior

    PubMed Central

    2008-01-01

    Dynamic organization of the cell interior, which is crucial for cell function, largely depends on the microtubule cytoskeleton. Microtubules move and position organelles by pushing, pulling, or sliding. Pushing forces can be generated by microtubule polymerization, whereas pulling typically involves microtubule depolymerization or molecular motors, or both. Sliding between a microtubule and another microtubule, an organelle, or the cell cortex is also powered by molecular motors. Although numerous examples of microtubule-based pushing and pulling in living cells have been observed, it is not clear why different cell types and processes employ different mechanisms. This review introduces a classification of microtubule-based positioning strategies and discusses the efficacy of pushing and pulling. The positioning mechanisms based on microtubule pushing are efficient for movements over small distances, and for centering of organelles in symmetric geometries. Mechanisms based on pulling, on the other hand, are typically more elaborate, but are necessary when the distances to be covered by the organelles are large, and when the geometry is asymmetric and complex. Thus, taking into account cell geometry and the length scale of the movements helps to identify general principles of the intracellular layout based on microtubule forces. PMID:18404264

  12. Growth of platinum fibers using the micro-pulling-down method

    NASA Astrophysics Data System (ADS)

    Nihei, Takayuki; Yokota, Yuui; Arakawa, Mototaka; Ohashi, Yuji; Kurosawa, Shunsuke; Kamada, Kei; Chani, Valery; Yoshikawa, Akira

    2017-06-01

    Platinum (Pt) crystalline fibers were grown from the melt by the micro-pulling-down (μ-PD) method using the ZrO2 ceramics crucible. The diameter of the grown Pt fiber was controlled by the ϕ1 mm outlet made at the bottom of the crucible and the Pt fiber of 0.95±0.03 mm in diameter and over 5 m in length was obtained at 10 mm/min pulling-down rate. In addition, the Pt fiber was grown at 1-110 mm/min pulling rates while the liquid-solid interface reached the bottom of the crucible and the crystal growth became unstable at 120 mm/min pulling rate. Few grain boundaries were observed in the scanning electron microscopy image of the Pt fibers and there were some spots with high intensity in the pole figures.

  13. Colorado Youth Risk Behavior Survey for Youth in Out-of-Home Placement.

    ERIC Educational Resources Information Center

    Colorado State Dept. of Education, Denver. Prevention Initiatives Unit.

    This report describes the results of a survey on out-of-school youth's health risk behaviors. The behaviors studied include unintentional and intentional injuries; tobacco use; alcohol, and other drug use; sexual behaviors; dietary behaviors that cause health problems; mental well being; and physical inactivity. Seventy-eight percent of all the…

  14. Use of steel fibres recovered from waste tyres as reinforcement in concrete: pull-out behaviour, compressive and flexural strength.

    PubMed

    Aiello, M A; Leuzzi, F; Centonze, G; Maffezzoli, A

    2009-06-01

    The increasing amount of waste tyres worldwide makes the disposition of tyres a relevant problem to be solved. In the last years over three million tons of waste tyres were generated in the EU states [ETRA, 2006. Tyre Technology International - Trends in Tyre Recycling. http://www.etra-eu.org]; most of them were disposed into landfills. Since the European Union Landfill Directive (EU Landfill, 1999) aims to significantly reduce the landfill disposal of waste tyres, the development of new markets for the tyres becomes fundamental. Recently some research has been devoted to the use of granulated rubber and steel fibres recovered from waste tyres in concrete. In particular, the concrete obtained by adding recycled steel fibres evidenced a satisfactory improvement of the fragile matrix, mostly in terms of toughness and post-cracking behaviour. As a consequence RSFRC (recycled steel fibres reinforced concrete) appears a promising candidate for both structural and non-structural applications. Within this context a research project was undertaken at the University of Salento (Italy) aiming to investigate the mechanical behaviour of concrete reinforced with RSF (recycled steel fibres) recovered from waste tyres by a mechanical process. In the present paper results obtained by the experimental work performed up to now are reported. In order to evaluate the concrete-fibres bond characteristics and to determine the critical fibre length, pull-out tests were initially carried out. Furthermore compressive strength of concrete was evaluated for different volume ratios of added RSF and flexural tests were performed to analyze the post-cracking behaviour of RSFRC. For comparison purposes, samples reinforced with industrial steel fibres (ISF) were also considered. Satisfactory results were obtained regarding the bond between recycled steel fibres and concrete; on the other hand compressive strength of concrete seems unaffected by the presence of fibres despite their irregular

  15. Actin cable distribution and dynamics arising from cross-linking, motor pulling, and filament turnover

    PubMed Central

    Tang, Haosu; Laporte, Damien; Vavylonis, Dimitrios

    2014-01-01

    The growth of fission yeast relies on the polymerization of actin filaments nucleated by formin For3p, which localizes at tip cortical sites. These actin filaments bundle to form actin cables that span the cell and guide the movement of vesicles toward the cell tips. A big challenge is to develop a quantitative understanding of these cellular actin structures. We used computer simulations to study the spatial and dynamical properties of actin cables. We simulated individual actin filaments as semiflexible polymers in three dimensions composed of beads connected with springs. Polymerization out of For3p cortical sites, bundling by cross-linkers, pulling by type V myosin, and severing by cofilin are simulated as growth, cross-linking, pulling, and turnover of the semiflexible polymers. With the foregoing mechanisms, the model generates actin cable structures and dynamics similar to those observed in live-cell experiments. Our simulations reproduce the particular actin cable structures in myoVΔ cells and predict the effect of increased myosin V pulling. Increasing cross-linking parameters generates thicker actin cables. It also leads to antiparallel and parallel phases with straight or curved cables, consistent with observations of cells overexpressing α-actinin. Finally, the model predicts that clustering of formins at cell tips promotes actin cable formation. PMID:25103242

  16. On the Push-Pull Mobile Learning of Electric Welding

    ERIC Educational Resources Information Center

    Chung, Chih-Chao; Dzan, Wei-Yuan; Cheng, Yuh-Ming; Lou, Shi-Jer

    2017-01-01

    This study aims to explore the learning effects and attitudes of students in the course electric welding practice in a university of science and technology to which the push-pull technology-based mobile learning system is applied. In this study, the push-pull technology is adopted to establish a mobile learning system and develop the Push-pull…

  17. Push-pull switching power amplifier

    NASA Technical Reports Server (NTRS)

    Cuk, Slobodan M. (Inventor)

    1980-01-01

    A true push-pull switching power amplifier is disclosed utilizing two dc-to-dc converters. Each converter is comprised of two inductances, one inductance in series with a DC source and the other inductor in series with the output load, and an electrical energy transferring device with storage capability, namely storage capacitance, with suitable switching means between the inductances to obtain DC level conversion, where the switching means allows bidirectional current (and power) flow, and the switching means of one dc-to-dc converter is driven by the complement of a square-wave switching signal for the other dc-to-dc converter for true push-pull operation. For reduction of current ripple, the inductances in each of the two converters may be coupled, and with proper design of the coupling, the ripple can be reduced to zero at either the input or the output, but preferably the output.

  18. Scapula kinematics of pull-up techniques: Avoiding impingement risk with training changes.

    PubMed

    Prinold, Joe A I; Bull, Anthony M J

    2016-08-01

    Overhead athletic activities and scapula dyskinesia are linked with shoulder pathology; pull-ups are a common training method for some overhead sports. Different pull-up techniques exist: anecdotally some are easier to perform, and others linked to greater incidences of pathology. This study aims to quantify scapular kinematics and external forces for three pull-up techniques, thus discussing potential injury implications. An observational study was performed with eleven participants (age=26.8±2.4 years) who regularly perform pull-ups. The upward motions of three pull-up techniques were analysed: palms facing anterior, palms facing posterior and wide-grip. A skin-fixed scapula tracking technique with attached retro-reflective markers was used. High intra-participant repeatability was observed: mean coefficients of multiple correlations of 0.87-1.00 in humerothoracic rotations and 0.77-0.90 for scapulothoracic rotations. Standard deviations of hand force was low: <5% body weight. Significantly different patterns of humerothoracic, scapulothoracic and glenohumeral kinematics were observed between the pull-up techniques. The reverse technique has extreme glenohumeral internal-external rotation and large deviation from the scapula plane. The wide technique has a reduced range of pro/retraction in the same HT plane of elevation and 90° of arm abduction with 45° external rotation was observed. All these factors suggest increased sub-acromial impingement risk. The scapula tracking technique showed high repeatability. High arm elevation during pull-ups reduces sub-acromial space and increases pressure, increasing the risk of impingement injury. Wide and reverse pull-ups demonstrate kinematics patterns linked with increased impingement risk. Weight-assisted front pull-ups require further investigation and could be recommended for weaker participants. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  19. Optical pulling force and conveyor belt effect in resonator-waveguide system.

    PubMed

    Intaraprasonk, Varat; Fan, Shanhui

    2013-09-01

    We present the theoretical condition and actual numerical design that achieves an optical pulling force in resonator-waveguide systems, where the direction of the force on the resonator is in the opposite direction to the input light in the waveguide. We also show that this pulling force can occur in conjunction with the lateral optical equilibrium effect, such that the resonator is maintained at the fixed distance from the waveguide while experiencing the pulling force.

  20. Are single-well "push-pull" tests suitable tracer methods for aquifer characterization?

    NASA Astrophysics Data System (ADS)

    Hebig, Klaus; Zeilfelder, Sarah; Ito, Narimitsu; Machida, Isao; Scheytt, Traugott; Marui, Atsunao

    2013-04-01

    Recently, investigations were conducted for geological and hydrogeological characterisation of the sedimentary coastal basin of Horonobe (Hokkaido, Japan). Coastal areas are typical geological settings in Japan, which are less tectonically active than the mountain ranges. In Asia, and especially in Japan, these areas are often densely populated. Therefore, it is important to investigate the behaviour of solutes in such unconsolidated aquifers. In such settings sometimes only single boreholes or groundwater monitoring wells are available for aquifer testing for various reasons, e.g. depths of more than 100 m below ground level and slow groundwater velocities due to density driven flow. A standard tracer test with several involved groundwater monitoring wells is generally very difficult or even not possible at these depths. One of the most important questions in our project was how we can obtain information about chemical and hydraulic properties in such aquifers. Is it possible to characterize solute transport behaviour parameters with only one available groundwater monitoring well or borehole? A so-called "push-pull" test may be one suitable method for aquifer testing with only one available access point. In a push-pull test a known amount of several solutes including a conservative tracer is injected into the aquifer ("push") and afterwards extracted ("pull"). The measured breakthrough curve during the pumping back phase can then be analysed. This method has already been used previously with various aims, also in the recent project (e.g. Hebig et al. 2011, Zeilfelder et al. 2012). However, different test setups produced different tracer breakthrough curves. As no systematic evaluation of this aquifer tracer test method was done so far, nothing is known about its repeatability. Does the injection and extraction rate influence the shape of the breakthrough curve? Which role plays the often applied "chaser", which is used to push the test solution out from the

  1. The Tablecloth Pull Revisited

    ERIC Educational Resources Information Center

    Vollmer, Michael; Mollmann, Klaus-Peter

    2015-01-01

    A very old and well-known magical trick is the so-called tablecloth pull. A table is covered with a tablecloth, on top of which are certain objects. The task is to remove the tablecloth while the objects--which must not be touched--stay on top of the table. This article describes the physics behind the experiment, and presents examples recorded…

  2. Movement suppression time-out for undesirable behavior in psychotic and severely developmentally delayed children.

    PubMed

    Rolider, A; Van Houten, R

    1985-01-01

    The effects of a movement suppression time-out, which involved punishing any movement or verbalization while a client is in the time-out area, were evaluated in four experiments. The first experiment examined the effects of a DRO procedure and movement suppression plus DRO in suppressing self-injurious behavior in a psychotic child in three different situations. In Experiment 2, the results of the previous experiment were replicated with two dangerous behaviors in a second psychotic child. In a third experiment, movement suppression plus DRO was compared with contingent restraint in reducing inappropriate poking behavior in two settings. The movement suppression procedure eliminated poking whereas contingent restraint had little effect. In the final experiment, movement suppression time-out alone was compared with exclusionary time-out alone and simple corner time-out alone. Self-stimulation occurred at high levels during the exclusionary and simple corner time-out procedures. Self-stimulation was either suppressed or reduced during movement suppression time-out. The movement suppression time-out procedure produced a larger reduction in the target behavior in all three children. The effectiveness of the movement suppression procedure was explained in terms of the suppression of self-stimulation while the time-out procedure was being applied.

  3. Thermal, size and surface effects on the nonlinear pull-in of small-scale piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    SoltanRezaee, Masoud; Ghazavi, Mohammad-Reza

    2017-09-01

    Electrostatically actuated miniature wires/tubes have many operational applications in the high-tech industries. In this research, the nonlinear pull-in instability of piezoelectric thermal small-scale switches subjected to Coulomb and dissipative forces is analyzed using strain gradient and modified couple stress theories. The discretized governing equation is solved numerically by means of the step-by-step linearization method. The correctness of the formulated model and solution procedure is validated through comparison with experimental and several theoretical results. Herein, the length-scale, surface energy, van der Waals attraction and nonlinear curvature are considered in the present comprehensive model and the thermo-electro-mechanical behavior of cantilever piezo-beams are discussed in detail. It is found that the piezoelectric actuation can be used as a design parameter to control the pull-in phenomenon. The obtained results are applicable in stability analysis, practical design and control of actuated miniature intelligent devices.

  4. Multifilament cellulose/chitin blend yarn spun from ionic liquids.

    PubMed

    Mundsinger, Kai; Müller, Alexander; Beyer, Ronald; Hermanutz, Frank; Buchmeiser, Michael R

    2015-10-20

    Cellulose and chitin, both biopolymers, decompose before reaching their melting points. Therefore, processing these unmodified biopolymers into multifilament yarns is limited to solution chemistry. Especially the processing of chitin into fibers is rather limited to distinctive, often toxic or badly removable solvents often accompanied by chemical de-functionalization to chitosan (degree of acetylation, DA, <50%). This work proposes a novel method for the preparation of cellulose/chitin blend fibers using ionic liquids (ILs) as gentle, removable, recyclable and non-deacetylating solvents. Chitin and cellulose are dissolved in ethylmethylimidazolium propionate ([C2mim](+)[OPr](-)) and the obtained one-pot spinning dope is used to produce multifilament fibers by a continuous wet-spinning process. Both the rheology of the corresponding spinning dopes and the structural and physical properties of the obtained fibers have been determined for different biopolymer ratios. With respect to medical or hygienic application, the cellulose/chitin blend fiber show enhanced water retention capacity compared to pure cellulose fibers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Affective and Sensory Correlates of Hair Pulling in Pediatric Trichotillomania

    ERIC Educational Resources Information Center

    Meunier, Suzanne A.; Tolin, David F.; Franklin, Martin

    2009-01-01

    Hair pulling in pediatric populations has not received adequate empirical study. Investigations of the affective and sensory states contributing to the etiology and maintenance of hair pulling may help to elucidate the classification of trichotillomania (TTM) as an impulse control disorder or obsessive-compulsive spectrum disorder. The current…

  6. 13. PULL CURVE RECONSTRUCTION: Photocopy of a September 1907 photograph ...

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

    13. PULL CURVE RECONSTRUCTION: Photocopy of a September 1907 photograph showing the reconstruction of a pull curve at Sacramento and Larkin Streets following the earthquake and fire. The tracks belong to United Railroads of San Francisco. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  7. Initial Study of Friction Pull Plug Welding

    NASA Technical Reports Server (NTRS)

    Rich, Brian S.

    1999-01-01

    Pull plug friction welding is a new process being developed to conveniently eliminate defects from welded plate tank structures. The general idea is to drill a hole of precise, optimized dimensions and weld a plug into it, filling the hole perfectly. A conically-shaped plug is rotated at high angular velocity as it is brought into contact with the plate material in the hole. As the plug is pulled into the hole, friction rapidly raises the temperature to the point at which the plate material flows plastically. After a brief heating phase, the plug rotation is terminated. The plug is then pulled upon with a forging force, solidly welding the plug into the hole in the plate. Three aspects of this process were addressed in this study. The transient temperature distribution was analyzed based on slightly idealized boundary conditions for different plug geometries. Variations in hole geometry and ram speed were considered, and a program was created to calculate volumes of displaced material and empty space, as well as many other relevant dimensions. The relation between the axially applied forging force and the actual forging pressure between the plate and plug surfaces was determined for various configurations.

  8. Evaluations of Out-of-Role Implicit Behavior for Male and Female Managers.

    ERIC Educational Resources Information Center

    Remland, Martin; And Others

    A study was conducted to examine whether androgynous individuals would view out-of-role implicit behavior by both male and female managers more positively than would either masculine or feminine individuals and whether low status behavior by the managers would be rated as being more considerate than high status behavior. Two weeks after completing…

  9. Fractional Models Simulating Non-Fickian Behavior in Four-Stage Single-Well Push-Pull Tests

    NASA Astrophysics Data System (ADS)

    Chen, Kewei; Zhan, Hongbin; Yang, Qiang

    2017-11-01

    Four-stage single-well push-pull (SWPP) tracer tests, including injection, chasing, resting, and pumping, were conducted in a fractured aquifer at Newark basin. An anomalous transport phenomenon observed in the SWPP tests is the linear decline of breakthrough curves (BTCs) at late time with slope of -1.8 in log-log plots. A time-dependent fractional model is developed to interpret the anomalous transport behavior. This model considers a time-dependent power law memory function and a time-dependent fractional advection-dispersion operator. The fractional advection-dispersion equations (fADE) are solved in a radial coordinate system using the implicit Euler method. A semi-analytical solution of the first-order rate-limited mobile-immobile model (FORMIM) is derived for comparison. It is found that both the nonlocal transport in time and space can produce the long-tailed BTC. A smaller time-fractional or space-fractional index leads to a lower peak concentration and a larger late-time slope. The mass distribution of the fractional-in-space (FS) model exhibits power law decline at the leading plume edge. Early breakthrough during pumping is not observed because the mobile mass at the start of pumping is nonzero and more concentrated near the wellbore. The capacity ratio is an important factor that affects the peak concentration. A larger capacity ratio leads to greater peak concentration. A smaller time-fractional index in the injection, chasing, or resting stage will move the BTC downward and the slope of the late time BTC is determined by the space-fractional index over all stages and the time-fractional index in the pumping stage. The capability of the existing models to recover the BTC of the SWPP test is discussed and some guidelines for how to choose the appropriate model to interpret the SWPP test data are proposed.

  10. The Hauling-Out Behavior of the Pacific Walrus.

    DTIC Science & Technology

    1980-09-08

    natural history of Pacific walruses, Odobenus rosmarus diver- gens. We concentrated on walrus hauling-out behavior and the associated enviro- mental...Unclassified Unclassified This refs rnoy be reproduced. W - -t-. A - ABSTRACT Important questions on the natural history of marine mammals need to be answered...before management can be placed on a more certain basis. We investigated one aspect of the natural history of Pacific walruses, Odobenus rosmarus

  11. A new model for the initiation, crustal architecture, and extinction of pull-apart basins

    NASA Astrophysics Data System (ADS)

    van Wijk, J.; Axen, G. J.; Abera, R.

    2015-12-01

    We present a new model for the origin, crustal architecture, and evolution of pull-apart basins. The model is based on results of three-dimensional upper crustal numerical models of deformation, field observations, and fault theory, and answers many of the outstanding questions related to these rifts. In our model, geometric differences between pull-apart basins are inherited from the initial geometry of the strike-slip fault step which results from early geometry of the strike-slip fault system. As strike-slip motion accumulates, pull-apart basins are stationary with respect to underlying basement and the fault tips may propagate beyond the rift basin. Our model predicts that the sediment source areas may thus migrate over time. This implies that, although pull-apart basins lengthen over time, lengthening is accommodated by extension within the pull-apart basin, rather than formation of new faults outside of the rift zone. In this aspect pull-apart basins behave as narrow rifts: with increasing strike-slip the basins deepen but there is no significant younging outward. We explain why pull-apart basins do not go through previously proposed geometric evolutionary stages, which has not been documented in nature. Field studies predict that pull-apart basins become extinct when an active basin-crossing fault forms; this is the most likely fate of pull-apart basins, because strike-slip systems tend to straighten. The model predicts what the favorable step-dimensions are for the formation of such a fault system, and those for which a pull-apart basin may further develop into a short seafloor-spreading ridge. The model also shows that rift shoulder uplift is enhanced if the strike-slip rate is larger than the fault-propagation rate. Crustal compression then contributes to uplift of the rift flanks.

  12. Fiber pulling apparatus modification

    NASA Technical Reports Server (NTRS)

    Smith, Guy A.; Workman, Gary L.

    1992-01-01

    A reduced gravity fiber pulling apparatus (FPA) was constructed in order to study the effects of gravity on glass fiber formation. The apparatus was specifically designed and built for use on NASA's KC-135 aircraft. Four flights have been completed to date during which E-glass fiber was successfully produced in simulated zero, high, and lunar gravity environments. In addition simulated lunar soil samples were tested for their fiber producing properties using the FPA.

  13. Pulling a patient up in bed

    MedlinePlus

    ... from rubbing can scrape or tear the person's skin. Common areas at risk for friction are the shoulders, back, buttocks, elbows, and heels. Never move patients up by grabbing them under their arms and pulling. This can injure their shoulders.

  14. A Study of Investigating Adolescents' Eating out Behavior by Using Analytic Hierarchy Process

    ERIC Educational Resources Information Center

    Lan, Tian-Syung; Lan, Yu-Hua; Chen, Pin-Chang; Lo, Wen-Chi

    2017-01-01

    The main purpose of this study is to understand the factors affecting adolescents' eating out behavior, as well as to develop scientific principles for selection of factors affecting adolescents' eating out behavior. According to literature review and expert questionnaire survey, this study obtained the factors affecting adolescents' choice to eat…

  15. Push and pull strategies: applications for health care marketing.

    PubMed

    Kingsley, B R

    1987-08-01

    As health care markets mature and expand, strategies available in other industries become useful. This article examines how traditional push-pull strategies apply to health care. Marketers using a push strategy recognize that the sale of their services or goods is dependent upon the endorsement of a middleman and promote their product through the middleman. Those using a pull strategy market directly to the consumer. In this article, the author outlines the advantages and disadvantages of using each strategy.

  16. Second-look arthroscopic assessment and clinical results of modified pull-out suture for posterior root tear of the medial meniscus.

    PubMed

    Cho, Jin-Ho; Song, Jae-Gwang

    2014-06-01

    To identify the structural integrity of the healing site after arthroscopic repair of a posterior root tear of the medial meniscus by second-look arthroscopy and to determine the clinical relevance of the findings. From January 2005 to December 2010, 20 consecutive patients underwent arthroscopic modified pull-out suture repair for a posterior root tear of the medial meniscus. Thirteen patients were available for second-look arthroscopic evaluation. The healing status of the medial meniscus was classified as complete healing, lax healing, scar tissue healing, and failed healing. We evaluated the correlation between the clinical symptoms and second-look arthroscopic findings. Clinical evaluation was based on the Lysholm knee scores and Hospital for Special Surgery (HSS) scores. There were 4 cases of complete healing, 4 lax healing, 4 scar tissue healing, and 1 failed healing. The healing status of the repaired meniscus appeared to be related to the clinical symptoms. Patients who achieved complete tissue healing had no complaint. The healing status exhibited no relationship with age, mechanical axis, degree of subluxation, and symptom duration. The mean Lysholm score improved from 34.7 preoperatively to 75.6 at follow-up and the mean HSS score also significantly increased from 33.5 to 82.2. We achieved 4 complete and 8 partial healing (lax or scar) of the medial meniscus in this retrospective case series of posterior horn meniscus root repairs performed by 1 surgeon. Further research is needed to clarify why all patients showed clinical improvement despite findings of partial healing on second-look arthroscopy.

  17. Second-Look Arthroscopic Assessment and Clinical Results of Modified Pull-Out Suture for Posterior Root Tear of the Medial Meniscus

    PubMed Central

    Song, Jae-Gwang

    2014-01-01

    Purpose To identify the structural integrity of the healing site after arthroscopic repair of a posterior root tear of the medial meniscus by second-look arthroscopy and to determine the clinical relevance of the findings. Materials and Methods From January 2005 to December 2010, 20 consecutive patients underwent arthroscopic modified pull-out suture repair for a posterior root tear of the medial meniscus. Thirteen patients were available for second-look arthroscopic evaluation. The healing status of the medial meniscus was classified as complete healing, lax healing, scar tissue healing, and failed healing. We evaluated the correlation between the clinical symptoms and second-look arthroscopic findings. Clinical evaluation was based on the Lysholm knee scores and Hospital for Special Surgery (HSS) scores. Results There were 4 cases of complete healing, 4 lax healing, 4 scar tissue healing, and 1 failed healing. The healing status of the repaired meniscus appeared to be related to the clinical symptoms. Patients who achieved complete tissue healing had no complaint. The healing status exhibited no relationship with age, mechanical axis, degree of subluxation, and symptom duration. The mean Lysholm score improved from 34.7 preoperatively to 75.6 at follow-up and the mean HSS score also significantly increased from 33.5 to 82.2. Conclusions We achieved 4 complete and 8 partial healing (lax or scar) of the medial meniscus in this retrospective case series of posterior horn meniscus root repairs performed by 1 surgeon. Further research is needed to clarify why all patients showed clinical improvement despite findings of partial healing on second-look arthroscopy. PMID:24944976

  18. Self-Destructive Behavior in Women.

    ERIC Educational Resources Information Center

    Kessel, Greer; Chrisler, Joan C.

    Trichotillomania (hair-pulling) and delicate self-cutting are self-destructive behaviors which utilize the body as a vehicle for self-expression. Like anorexia and bulimia, these behaviors occur primarily in young women. This study compared groups of women college students who engage in these self-destructive behaviors with those who do not. It…

  19. Push-pull aminobithiophenes--highly fluorescent stable fluorophores.

    PubMed

    Dong, Yanmei; Bolduc, Andréanne; McGregor, Nicholas; Skene, W G

    2011-04-01

    Stable 2-aminobithiophenes were prepared using the Gewald reaction. The resulting push-pull bithiophenes exhibited both unprecedented high fluorescence yields and stability in addition to demonstrating fluorescence on-off properties.

  20. Characterization and modeling of tensile behavior of ceramic woven fabric composites

    NASA Technical Reports Server (NTRS)

    Kuo, Wen-Shyong; Chen, Wennei Y.; Parvizi-Majidi, Azar; Chou, Tsu-Wei

    1991-01-01

    This paper examines the tensile behavior of SiC/SiC fabric composites. In the characterization effort, the stress-strain relation and damage evolution are studied with a series of loading and unloading tensile test experiments. The stress-strain relation is linear in response to the initial loading and becomes nonlinear when loading exceeds the proportional limit. Transverse cracking has been observed to be a dominant damage mode governing the nonlinear deformation. The damage is initiated at the inter-tow pores where fiber yarns cross over each other. In the modeling work, the analysis is based upon a fiber bundle model, in which fiber undulation in the warp and fill directions and gaps among fiber yarns have been taken into account. Two limiting cases of fabric stacking arrangements are studied. Closed form solutions are obtained for the composite stiffness and Poisson's ratio. Transverse cracking in the composite is discussed by applying a constant failure strain criterion.

  1. AORN ergonomic tool 7: pushing, pulling, and moving equipment on wheels.

    PubMed

    Waters, Thomas; Lloyd, John D; Hernandez, Edward; Nelson, Audrey

    2011-09-01

    Pushing and pulling equipment in and around the OR can place high shear force demands on perioperative team members' shoulder and back muscles and joints. These high forces may lead to work-related musculoskeletal disorders. AORN Ergonomic Tool 7: Pushing, Pulling, and Moving Equipment on Wheels can help perioperative team members assess the risk of pushing and pulling tasks in the perioperative setting. The tool provides evidence-based suggestions about when assistive devices should be used for these tasks and is based on current ergonomic safety concepts, scientific evidence, and knowledge of effective technology and procedures, including equipment and devices for safe patient handling. Published by Elsevier Inc.

  2. Factors affecting minimum push and pull forces of manual carts.

    PubMed

    Al-Eisawi, K W; Kerk, C J; Congleton, J J; Amendola, A A; Jenkins, O C; Gaines, W

    1999-06-01

    The minimum forces needed to manually push or pull a 4-wheel cart of differing weights with similar wheel sizes from a stationary state were measured on four floor materials under different conditions of wheel width, diameter, and orientation. Cart load was increased from 0 to 181.4 kg in increments of 36.3 kg. The floor materials were smooth concrete, tile, asphalt, and industrial carpet. Two wheel widths were tested: 25 and 38 mm. Wheel diameters were 51, 102, and 153 mm. Wheel orientation was tested at four levels: F0R0 (all four wheels aligned in the forward direction), F0R90 (the two front wheels, the wheels furthest from the cart handle, aligned in the forward direction and the two rear wheels, the wheels closest to the cart handle, aligned at 90 degrees to the forward direction), F90R0 (the two front wheels aligned at 90 degrees to the forward direction and the two rear wheels aligned in the forward direction), and F90R90 (all four wheels aligned at 90 degrees to the forward direction). Wheel width did not have a significant effect on the minimum push/pull forces. The minimum push/pull forces were linearly proportional to cart weight, and inversely proportional to wheel diameter. The coefficients of rolling friction were estimated as 2.2, 2.4, 3.3, and 4.5 mm for hard rubber wheels rolling on smooth concrete, tile, asphalt, and industrial carpet floors, respectively. The effect of wheel orientation was not consistent over the tested conditions, but, in general, the smallest minimum push/pull forces were measured with all four wheels aligned in the forward direction, whereas the largest minimum push/pull forces were measured when all four wheels were aligned at 90 degrees to the forward direction. There was no significant difference between the push and pull forces when all four wheels were aligned in the forward direction.

  3. The Effects of Teacher-Student Small Talk on Out-of-Seat Behavior

    ERIC Educational Resources Information Center

    Patterson, Steven T.

    2009-01-01

    This paper presents the results of a function-based study initiated by a general education teacher to reduce a general education student's out-of-seat behavior. Procedures included direct observation, data collection, functional behavior assessment using a Functional Assessment Protocol (FAP; Schroeder, n.d.), hypothesis development, and creating…

  4. An Investigation into the Cognition Behind Spontaneous String Pulling in New Caledonian Crows

    PubMed Central

    Taylor, Alex H.; Medina, Felipe S.; Holzhaider, Jennifer C.; Hearne, Lindsay J.; Hunt, Gavin R.; Gray, Russell D.

    2010-01-01

    The ability of some bird species to pull up meat hung on a string is a famous example of spontaneous animal problem solving. The “insight” hypothesis claims that this complex behaviour is based on cognitive abilities such as mental scenario building and imagination. An operant conditioning account, in contrast, would claim that this spontaneity is due to each action in string pulling being reinforced by the meat moving closer and remaining closer to the bird on the perch. We presented experienced and naïve New Caledonian crows with a novel, visually restricted string-pulling problem that reduced the quality of visual feedback during string pulling. Experienced crows solved this problem with reduced efficiency and increased errors compared to their performance in standard string pulling. Naïve crows either failed or solved the problem by trial and error learning. However, when visual feedback was available via a mirror mounted next to the apparatus, two naïve crows were able to perform at the same level as the experienced group. Our results raise the possibility that spontaneous string pulling in New Caledonian crows may not be based on insight but on operant conditioning mediated by a perceptual-motor feedback cycle. PMID:20179759

  5. The geometry of pull-apart basins in the southern part of Sumatran strike-slip fault zone

    NASA Astrophysics Data System (ADS)

    Aribowo, Sonny

    2018-02-01

    Models of pull-apart basin geometry have been described by many previous studies in a variety tectonic setting. 2D geometry of Ranau Lake represents a pull-apart basin in the Sumatran Fault Zone. However, there are unclear geomorphic traces of two sub-parallel overlapping strike-slip faults in the boundary of the lake. Nonetheless, clear geomorphic traces that parallel to Kumering Segment of the Sumatran Fault are considered as inactive faults in the southern side of the lake. I demonstrate the angular characteristics of the Ranau Lake and Suoh complex pull-apart basins and compare with pull-apart basin examples from published studies. I use digital elevation model (DEM) image to sketch the shape of the depression of Ranau Lake and Suoh Valley and measure 2D geometry of pull-apart basins. This study shows that Ranau Lake is not a pull-apart basin, and the pull-apart basin is actually located in the eastern side of the lake. Since there is a clear connection between pull-apart basin and volcanic activity in Sumatra, I also predict that the unclear trace of the pull-apart basin near Ranau Lake may be covered by Ranau Caldera and Seminung volcanic products.

  6. A demonstration of NIOSH push-pull ventilation criteria.

    PubMed

    Klein, M K

    1987-03-01

    This paper summarizes the results of a study performed on an actual chrome plating tank in order to validate criteria for push-pull ventilation systems developed by Huebener and Hughes at NIOSH. Validation of the criteria was made by taking area industrial hygiene samples for hexavalent and total chrome at ten locations around the plating tank. The sampling was performed during actual production runs or while the tank was operating with a dummy load. The sampling data are summarized. The data show that the push-pull system, operating at Huebener's criteria, could control emissions to below the current standards and guidelines. Conclusions and recommendations are included.

  7. An analysis of the wear behavior of SiC whisker reinforced alumina from 25 to 1200 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher

    1991-01-01

    A model is described for predicting the wear behavior of whisker reinforced ceramics. The model was successfully applied to a silicon carbide whisker reinforced alumina ceramic composite subjected to sliding contact. The model compares the friction forces on the whiskers due to sliding, which act to pull or push them out of the matrix, to the clamping or compressive forces on the whiskers due to the matrix, which act to hold the whiskers in the composite. At low temperatures, the whiskers are held strongly in the matrix and are fractured into pieces during the wear process along with the matrix. At elevated temperatures differential thermal expansion between the whiskers and matrix can cause loosening of the whiskers and lead to pullout during the wear process and to higher wear. The model, which represents the combination of elastic stress analysis and a friction heating analysis, predicts a transition temperature at which the strength of the whiskers equals the clamping force holding them in the matrix. Above the transition the whiskers are pulled out of the matrix during sliding, and below the transition the whiskers are simply fractured. The existence of the transition gives rise to a dual wear mode or mechanism behavior for this material which was observed in laboratory experiments. The results from this model correlate well with experimentally observed behavior indicating that the model may be useful in obtaining a better understanding of material behavior and in making material improvements.

  8. An analysis of the wear behavior of SiC whisker-reinforced alumina from 25 to 1200 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher

    1993-01-01

    A model is described for predicting the wear behavior of whisker reinforced ceramics. The model was successfully applied to a silicon carbide whisker reinforced alumina ceramic composite subjected to sliding contact. The model compares the friction forces on the whiskers due to sliding, which act to pull or push them out of the matrix, to the clamping or compressive forces on the whiskers due to the matrix, which act to hold the whiskers in the composite. At low temperatures, the whiskers are held strongly in the matrix and are fractured into pieces during the wear process along with the matrix. At elevated temperatures differential thermal expansion between the whiskers and matrix can cause loosening of the whiskers and lead to pullout during the wear process and to higher wear. The model, which represents the combination of elastic stress analysis and a friction heating analysis, predicts a transition temperature at which the strength of the whiskers equals the clamping force holding them in the matrix. Above the transition the whiskers are pulled out of the matrix during sliding, and below the transition the whiskers are simply fractured. The existence of the transition gives rise to a dual wear mode or mechanism behavior for this material which was observed in laboratory experiments. The results from this model correlate well with experimentally observed behavior indicating that the model may be useful in obtaining a better understanding of material behavior and in making material improvements.

  9. Collaborative Behavioral Management for Drug-Involved Parolees: Rationale and Design of the Step'n Out Study

    PubMed Central

    FRIEDMANN, PETER D.; KATZ, ELIZABETH C.; RHODES, ANNE G.; TAXMAN, FAYE S.; O'CONNELL, DANIEL J.; FRISMAN, LINDA K.; BURDON, WILLIAM M.; FLETCHER, BENNETT W.; LITT, MARK D.; CLARKE, JENNIFER; MARTIN, STEVEN S.

    2009-01-01

    This article describes the rationale, study design, and implementation for the Step'n Out study of the Criminal Justice Drug Abuse Treatment Studies. Step'n Out tests the relative effectiveness of collaborative behavioral management of drug-involved parolees. Collaborative behavioral management integrates the roles of parole officers and treatment counselors to provide role induction counseling, contract for pro-social behavior, and deliver contingent reinforcement of behaviors consistent with treatment objectives. The Step'n Out study will randomize 450 drug-involved parolees to collaborative behavioral management or usual parole. Follow-up at 3-and 9-months will assess primary outcomes of rearrest, crime and drug use. If collaborative behavioral management is effective, its wider adoption could improve the outcomes of community reentry of drug-involved ex-offenders. PMID:19809591

  10. Art Teaching Guides: Using Cloth and Trimmings, Yarns and Fibers, Grades 2-6. Curriculum Bulletin No. 8d, 1968-69 Series.

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY. Bureau of Curriculum Development.

    Creating with fabrics, yarns, and fibers--from early basic explorations in handling an assortment of cloths and trimmings, through experiments with stitching and weaving, to the designing and making of bags, hats, and costumes that children can use--is the focus of this curriculum guide. For each grade (2-6), guidelines are provided on (1)…

  11. Women "Opting out" of Academia: At What Cost?

    ERIC Educational Resources Information Center

    Schneider, Beth Z.; Carden, William; Francisco, Alyson; Jones, Thomas O., Jr.

    2011-01-01

    Previous research has examined the phenomenon of women "opting out" of the corporate environment. Much of this research has examined both "pull" factors--those of home and family life, and "push" factors--those within the organization which create a competitive environment where women feel they cannot achieve the same measure of success as their…

  12. IL-4 Knock out Mice Display Anxiety-like Behavior

    PubMed Central

    Moon, Morgan L.; Joesting, Jennifer J.; Blevins, Neil A.; Lawson, Marcus A.; Gainey, Stephen J.; Towers, Albert E.; McNeil, Leslie K.; Freund, Gregory G.

    2015-01-01

    Inflammation is a recognized antecedent and coincident factor when examining the biology of anxiety. Little is known, however, about how reductions in endogenous anti-inflammatory mediators impact anxiety. Therefore, mood- cognition- and anxiety-associated/like behaviors were examined in IL-4 knock out (KO) mice and wild-type (WT) mice. In comparison to WT mice, IL-4 KO mice demonstrated decreased burrowing and increased social exploration. No differences were seen in forced swim or saccharine preference testing. IL-4 KO mice had similar performance to WT mice in the Morris water maze and during object location and novel object recognition. In the elevated zero-maze, IL-4 KO mice, in comparison to WT mice, demonstrated anxiety-like behavior. Anxiety-like behavior in IL-4 KO mice was not observed, however, during open-field testing. Taken together, these data indicate that IL-4 KO mice display state, but not trait, anxiety suggesting that reductions in endogenous anti-inflammatory bioactives can engender subtypes of anxiety. PMID:25772794

  13. IL-4 Knock Out Mice Display Anxiety-Like Behavior.

    PubMed

    Moon, Morgan L; Joesting, Jennifer J; Blevins, Neil A; Lawson, Marcus A; Gainey, Stephen J; Towers, Albert E; McNeil, Leslie K; Freund, Gregory G

    2015-07-01

    Inflammation is a recognized antecedent and coincident factor when examining the biology of anxiety. Little is known, however, about how reductions in endogenous anti-inflammatory mediators impact anxiety. Therefore, mood- cognition- and anxiety-associated/like behaviors were examined in IL-4 knock out (KO) mice and wild-type (WT) mice. In comparison to WT mice, IL-4 KO mice demonstrated decreased burrowing and increased social exploration. No differences were seen in forced swim or saccharine preference testing. IL-4 KO mice had similar performance to WT mice in the Morris water maze and during object location and novel object recognition. In the elevated zero-maze, IL-4 KO mice, in comparison to WT mice, demonstrated anxiety-like behavior. Anxiety-like behavior in IL-4 KO mice was not observed, however, during open-field testing. Taken together, these data indicate that IL-4 KO mice display state, but not trait, anxiety suggesting that reductions in endogenous anti-inflammatory bioactives can engender subtypes of anxiety.

  14. A Highly Stretchable and Washable All-Yarn-Based Self-Charging Knitting Power Textile Composed of Fiber Triboelectric Nanogenerators and Supercapacitors.

    PubMed

    Dong, Kai; Wang, Yi-Cheng; Deng, Jianan; Dai, Yejing; Zhang, Steven L; Zou, Haiyang; Gu, Bohong; Sun, Baozhong; Wang, Zhong Lin

    2017-09-26

    Rapid advancements in stretchable and multifunctional wearable electronics impose a challenge on corresponding power devices that they should have comparable portability and stretchability. Here, we report a highly stretchable and washable all-yarn-based self-charging knitting power textile that enables both biomechanical energy harvesting and simultaneously energy storing by hybridizing triboelectrical nanogenerator (TENG) and supercapacitor (SC) into one fabric. With the weft-knitting technique, the power textile is qualified with high elasticity, flexibility, and stretchability, which can adapt to complex mechanical deformations. The knitting TENG fabric is able to generate electric energy with a maximum instantaneous peak power density of ∼85 mW·m -2 and light up at least 124 light-emitting diodes. The all-solid-state symmetrical yarn SC exhibits lightweight, good capacitance, high flexibility, and excellent mechanical and long-term stability, which is suitable for wearable energy storage devices. The assembled knitting power textile is capable of sustainably driving wearable electronics (for example, a calculator or temperature-humidity meter) with energy converted from human motions. Our work provides more opportunities for stretchable multifunctional power sources and potential applications in wearable electronics.

  15. Wicking Performance of Profiled Fibre Part B: Assessment of Fabric

    NASA Astrophysics Data System (ADS)

    Datta Roy, M.; Chattopadhyay, R.; Sinha, S. K.

    2018-06-01

    For moisture regulation, careful selection of fibre, fibre packing in yarns and fabric structure are necessary. Introducing selective porosity in yarn can significantly influence moisture transport properties in fabrics made out of profiled fibre yarn. The arrangement of fibres in the yarn and that of yarn in fabric provide wide variability in the size and shape of the passage of liquid to flow. A change in the cross sectional diameter of the capillary leads to a change in interfacial speed for liquid. The mechanism of liquid transmission in fabric is expected to be different from that in yarn in isolated state. Generally, openness in fabric offers least resistance to flow. However, at each cross over points of threads the pressure exerted by one set of yarn on another can influence the capillary geometry affecting flow of liquid. The present work reports on the investigation made to study the wicking performance of five sets of fabrics made out of five homogeneous profiled fibre yarns as weft and respective double yarns as warp. It was observed that the wicking time and height in the weft direction were different than that in the corresponding yarns. Interestingly, wicking height attained in warp direction and individual yarn in isolation does not show any significant difference. It was observed that the points of interlacements between warps and wefts were constantly splitting the fluid flow both in horizontal and vertical directions.

  16. Pushing and pulling: an assessment tool for occupational health and safety practitioners.

    PubMed

    Lind, Carl Mikael

    2018-03-01

    A tool has been developed for supporting practitioners when assessing manual pushing and pulling operations based on an initiative by two global companies in the manufacturing industry. The aim of the tool is to support occupational health and safety practitioners in risk assessment and risk management of pushing and pulling operations in the manufacturing and logistics industries. The tool is based on a nine-multiplier equation that includes a wide range of factors affecting an operator's health risk and capacity in pushing and pulling. These multipliers are based on psychophysical, physiological and biomechanical studies in combination with judgments from an expert group consisting of senior researchers and ergonomists. In order to consider usability, more than 50 occupational health and safety practitioners (e.g., ergonomists, managers, safety representatives and production personnel) participated in the development of the tool. An evaluation by 22 ergonomists supports that the push/pull tool is user friendly in general.

  17. Pulling out All the Stops

    ERIC Educational Resources Information Center

    Sezer, Renan

    2010-01-01

    This article discusses how an active learning environment was created in a community college class and a high school mathematics class using the same approach. In both settings the NCTM and AMATYC Standards, such as problem solving, communication, use of technology and alternate assessment, were fully embraced. The goal was to have students take…

  18. Mechanical behavior of a triaxially braided textile composite at high temperature

    NASA Astrophysics Data System (ADS)

    El Mourid, Amine

    The work presented in this thesis aimed at understanding the influence of viscoelasticity, temperature and aging on the mechanical behaviour of a textile composite using experimental, analytical and numerical tools. The studied material was a triaxially braided composite with fibres in the 0°/+/-60° directions. The yarns were made of carbon fibres, embedded in an MVK10 temperature resistant polyimide matrix. The first step consisted in developing analytical and numerical frameworks to predict viscoelastic behaviour in textile composites. Simulations were performed for both braided and woven textile architectures, at different stiffness contrasts and yarns volume fractions. The analytical framework accuracy was verified with the help of the numerical simulations. An important finding of this study was that the analytical framework, combined with the Mori-Tanaka model, leads to relatively accurate predictions for both the permanent and transient parts. Therefore, the authors believe that the Mori-Tanaka model with an adjusted aspect ratio to take into account yarn curvature is reliable for predicting viscoelastic behaviour in textile composites. The textile composite that was studied in this project did not display viscoelastic behaviour, due to the high yarn volume fraction. However, the framework remains relevant for higher temperature applications or lower yarn volume fractions. The second step was to investigate the temperature effect on the tensile behavior of the carbon/MVK10 triaxially braided composite material studied in this project. To achieve this goal, a series of room and high temperature tensile tests on both matrix and composite samples were performed. The tests on composite samples were performed along two different material directions at the maximum service temperature allowed by the Federal Aviation Administration for aircraft components, and a dedicated replication technique was developed in order to track crack densities as a function of

  19. Having a yarn about smoking: using action research to develop a 'no smoking' policy within an Aboriginal Health Organisation.

    PubMed

    Fletcher, Gillian; Fredericks, Bronwyn; Adams, Karen; Finlay, Summer; Andy, Simone; Briggs, Lyn; Hall, Robert

    2011-11-01

    This article reports on a culturally appropriate process of development of a smoke-free workplace policy within the peak Aboriginal Controlled Community Health Organisation in Victoria, Australia. Smoking is acknowledged as being responsible for at least 20% of all deaths in Aboriginal communities in Australia, and many Aboriginal health workers smoke. The smoke-free workplace policy was developed using the iterative, discursive and experience-based methodology of Participatory Action Research, combined with the culturally embedded concept of 'having a yarn'. Staff members initially identified smoking as a topic to be avoided within workplace discussions. This was due, in part, to grief (everyone had suffered a smoking-related bereavement). Further, there was anxiety that discussing smoking would result in culturally difficult conflict. The use of yarning opened up a safe space for discussion and debate, enabling development of a policy that was accepted across the organisation. Within Aboriginal organisations, it is not sufficient to focus on the outcomes of policy development. Rather, due attention must be paid to the process employed in development of policy, particularly when that policy is directly related to an emotionally and communally weighted topic such as smoking. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  20. Comparative Evaluation of Antiplaque Efficacy of Coconut Oil Pulling and a Placebo, Among Dental College Students: A Randomized Controlled Trial

    PubMed Central

    Kulkarni, Suhas; Madupu, Padma Reddy; Doshi, Dolar; Bandari, Srikanth Reddy; Srilatha, Adepu

    2017-01-01

    Introduction Oil pulling, has been extensively used as traditional Indian folk remedy since many years to prevent dental diseases and for strengthening teeth and gums. Aim To compare and evaluate antiplaque efficacy of coconut oil pulling with a placebo among dental students, in Hyderabad city of India. Materials and Methods A randomized controlled study was carried out among 40 dental students. Out of 40, 20 subjects were randomly assigned to study group and other 20 to control group. Subjects in the study group were given the coconut oil and control group a placebo, and advised to rinse for 10 minutes, once daily in the morning for a period of seven days. Plaque levels were assessed on day zero, third and seventh day using Turesky-Gilmore-Glickman Modification of the Quigley-Hein Plaque Index (1970) for both the groups. Results The mean plaque scores showed a significant difference at baseline, third day and seventh day among both study (p<0.001) and control groups (p<0.001). Group wise comparison revealed, though the mean plaque scores were low among study group on third day and seventh day on comparison with the control group, significant difference was noticed only on the seventh day. Furthermore, the mean percentage reduction of plaque scores were also significant only on the seventh day with a high mean plaque reduction among study groups (p<0.001). Conclusion Oil pulling is effective in controlling plaque levels. PMID:29207824

  1. The effect of a slack-pulling device in reducing operator physiological workload during log winching operations.

    PubMed

    Spinelli, Raffaele; Aalmo, Giovanna Ottaviani; Magagnotti, Natascia

    2015-01-01

    The authors conducted a comparative test to determine whether the introduction of a hydraulic slack puller allowed reducing the physiological workload of operators assigned to log winching tasks. The tests were conducted in northern Italy, on the mountains near Como. The study involved five volunteer subjects, considered representatives of the regional logging workforce. Physiological workload was determined by measuring the operators' heart rate upon completion of specific tasks. The slack puller improved the efficiency of downhill winching, since it allowed a single operator to pull out the cable on his own, without requiring the assistance of a colleague. However, introduction of the slack puller did not result in any reductions of operator physiological workload. The main stressor when working on a steep slope is moving up and down the slope: pulling a cable is only a secondary stressor. Any measures targeting secondary stressors are unlikely to produce dramatic reductions of operator workload.

  2. Design of push-pull system to control diesel particular matter inside a dead-end entry.

    PubMed

    Zheng, Yi; Thiruvengadam, Magesh; Lan, Hai; Tien, Jerry C

    Diesel particulate matter (DPM) is considered to be carcinogenic after prolonged exposure. With more diesel-powered equipment used in underground mines, miners' exposure to DPM has become an increasing concern. This paper used computational fluid dynamics method to study the DPM dispersion in a dead-end entry with loading operation. The effects of different push-pull ventilation systems on DPM distribution were evaluated to improve the working conditions for underground miners. The four push-pull systems considered include: long push and short pull tubing; short push and long pull tubing, long push and curved pull tubing, and short push and curved pull tubing. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup local ventilation, select DPM control strategies and for DPM annual training for underground miners.

  3. RACE pulls for shared control

    NASA Astrophysics Data System (ADS)

    Leahy, M. B., Jr.; Cassiday, B. K.

    1993-02-01

    Maintaining and supporting an aircraft fleet, in a climate of reduced manpower and financial resources, dictates effective utilization of robotics and automation technologies. To help develop a winning robotics and automation program the Air Force Logistics Command created the Robotics and Automation Center of Excellence (RACE). RACE is a command wide focal point. Race is an organic source of expertise to assist the Air Logistic Center (ALC) product directorates in improving process productivity through the judicious insertion of robotics and automation technologies. RACE is a champion for pulling emerging technologies into the aircraft logistic centers. One of those technology pulls is shared control. Small batch sizes, feature uncertainty, and varying work load conspire to make classic industrial robotic solutions impractical. One can view ALC process problems in the context of space robotics without the time delay. The ALC's will benefit greatly from the implementation of a common architecture that supports a range of control actions from fully autonomous to teleoperated. Working with national laboratories and private industry, we hope to transition shared control technology to the depot floor. This paper provides an overview of the RACE internal initiatives and customer support, with particular emphasis on production processes that will benefit from shared control technology.

  4. RACE pulls for shared control

    NASA Astrophysics Data System (ADS)

    Leahy, Michael B., Jr.; Cassiday, Brian K.

    1992-11-01

    Maintaining and supporting an aircraft fleet, in a climate of reduced manpower and financial resources, dictates effective utilization of robotics and automation technologies. To help develop a winning robotics and automation program the Air Force Logistics Command created the Robotics and Automation Center of Excellence (RACE). RACE is a command wide focal point. An organic source of expertise to assist the Air Logistic Center (ALC) product directorates in improving process productivity through the judicious insertion of robotics and automation technologies. RACE is a champion for pulling emerging technologies into the aircraft logistic centers. One of those technology pulls is shared control. The small batch sizes, feature uncertainty, and varying work load conspire to make classic industrial robotic solutions impractical. One can view ALC process problems in the context of space robotics without the time delay. The ALCs will benefit greatly from the implementation of a common architecture that supports a range of control actions from fully autonomous to teleoperated. Working with national laboratories and private industry we hope to transition shared control technology to the depot floor. This paper provides an overview of the RACE internal initiatives and customer support, with particular emphasis on production processes that will benefit from shared control technology.

  5. RACE pulls for shared control

    NASA Technical Reports Server (NTRS)

    Leahy, M. B., Jr.; Cassiday, B. K.

    1993-01-01

    Maintaining and supporting an aircraft fleet, in a climate of reduced manpower and financial resources, dictates effective utilization of robotics and automation technologies. To help develop a winning robotics and automation program the Air Force Logistics Command created the Robotics and Automation Center of Excellence (RACE). RACE is a command wide focal point. Race is an organic source of expertise to assist the Air Logistic Center (ALC) product directorates in improving process productivity through the judicious insertion of robotics and automation technologies. RACE is a champion for pulling emerging technologies into the aircraft logistic centers. One of those technology pulls is shared control. Small batch sizes, feature uncertainty, and varying work load conspire to make classic industrial robotic solutions impractical. One can view ALC process problems in the context of space robotics without the time delay. The ALC's will benefit greatly from the implementation of a common architecture that supports a range of control actions from fully autonomous to teleoperated. Working with national laboratories and private industry, we hope to transition shared control technology to the depot floor. This paper provides an overview of the RACE internal initiatives and customer support, with particular emphasis on production processes that will benefit from shared control technology.

  6. Upper body push and pull strength ratio in recreationally active adults.

    PubMed

    Negrete, Rodney J; Hanney, William J; Pabian, Patrick; Kolber, Morey J

    2013-04-01

    Agonist to antagonist strength data is commonly analyzed due to its association with injury and performance. The purpose of this study was to examine the agonist to antagonist ratio of upper body strength using two simple field tests (timed push up/timed modified pull up) in recreationally active adults and to establish the basis for reference standards. One hundred eighty (180) healthy recreationally active adults (111 females and 69 males, aged 18-45 years) performed two tests of upper body strength in random order: 1. Push-ups completed during 3 sets of 15 seconds with a 45 second rest period between each set and 2. Modified pull-ups completed during 3 sets of 15 seconds with a 45 second rest period between each set. The push-up to modified pull-up ratio for the males was 1.57:1, whereas females demonstrated a ratio of 2.72:1. The results suggest that for our group of healthy recreationally active subjects, the upper body "pushing" musculature is approximately 1.5-2.7 times stronger than the musculature involved for pulling. In this study, these recreationally active adults displayed greater strength during the timed push-ups than the modified pull-ups. The relationship of these imbalances to one's performance and or injury risk requires further investigation. The reference values, however, may serve the basis for future comparison and prospective investigations. The field tests in this study can be easily implemented by clinicians and an agonist/antagonist ratio can be determined and compared to our findings. 2b.

  7. Theoretical modeling and experimental study of dielectric loss of the multi-push-pull mode magnetoelectric laminate composites

    NASA Astrophysics Data System (ADS)

    Xu, Bingbing; Ma, Jiashuai; Fang, Cong; Yao, Meng; Di, Wenning; Li, Xiaobing; Luo, Haosu

    2018-02-01

    In this work, we establish a dielectric loss model for multi-push-pull mode ME laminate composites. It deduces that the total dielectric loss of the ME composites equals the linear average of the dielectric loss of piezoelectric plate and epoxy resin. But further analysis of this model has indicated that we can ignore the dielectric loss of epoxy resin. To verify this model, we use three kinds of epoxy resin with different dielectric loss to fabricate multi-push-pull mode PMNT/Metglas ME laminate composites respectively. It turns out that the different kinds of epoxy resin have little influence on the total dielectric loss, capacitance and piezoelectricity of the composites, which demonstrates that our model conforms to the practical case. Therefore, we can pay more attention to the mechanical properties of epoxy resin rather than its dielectric loss on fabricating the ME laminate composites.

  8. Raman spectrum method for characterization of pull-in voltages of graphene capacitive shunt switches

    NASA Astrophysics Data System (ADS)

    Li, Peng; You, Zheng; Cui, Tianhong

    2012-12-01

    An approach using Raman spectrum method is reported to measure pull-in voltages of graphene capacitive shunt switches. When the bias excesses the pull-in voltage, the Raman spectrum's intensity largely decreases. Two factors that contribute to the intensity reduction are investigated. Moreover, by monitoring the frequency shift of G peak and 2D band, we are able to detect the pull-in voltage and measure the strain change in graphene beams during switching.

  9. Core-Shell-Yarn-Based Triboelectric Nanogenerator Textiles as Power Cloths.

    PubMed

    Yu, Aifang; Pu, Xiong; Wen, Rongmei; Liu, Mengmeng; Zhou, Tao; Zhang, Ke; Zhang, Yang; Zhai, Junyi; Hu, Weiguo; Wang, Zhong Lin

    2017-12-26

    Although textile-based triboelectric nanogenerators (TENGs) are highly promising because they scavenge energy from their working environment to sustainably power wearable/mobile electronics, the challenge of simultaneously possessing the qualities of cloth remains. In this work, we propose a strategy for TENG textiles as power cloths in which core-shell yarns with core conductive fibers as the electrode and artificial polymer fibers or natural fibrous materials tightly twined around core conductive fibers are applied as the building blocks. The resulting TENG textiles are comfortable, flexible, and fashionable, and their production processes are compatible with industrial, large-scale textile manufacturing. More importantly, the comfortable TENG textiles demonstrate excellent washability and tailorability and can be fully applied in further garment processing. TENG textiles worn under the arm or foot have also been demonstrated to scavenge various types of energy from human motion, such as patting, walking, and running. All of these merits of proposed TENG textiles for clothing uses suggest their great potentials for viable applications in wearable electronics or smart textiles in the near future.

  10. Pushing and pulling in relation to musculoskeletal disorders: a review of risk factors.

    PubMed

    Hoozemans, M J; van der Beek, A J; Frings-Dresen, M H; van Dijk, F J; van der Woude, L H

    1998-06-01

    The objective was to review the literature on risk factors for musculoskeletal disorders related to pushing and pulling. The risk factors have been described and evaluated from four perspectives: epidemiology, psychophysics, physiology, and biomechanics. Epidemiological studies have shown, based on cross-sectional data, that pushing and pulling is associated with low back pain. Evidence with respect to complaints of other parts of the musculoskeletal system is lacking. Risk factors have been found to influence the maximum (acceptable) push or pull forces as well as the physiological and mechanical strain on the human body. The risk factors have been divided into: (a) work situation, such as distance, frequency, handle height, and cart weight, (b) actual working method and posture/movement/exerted forces, such as foot distance and velocity, and (c) worker's characteristics, such as body weight. Longitudinal epidemiological studies are needed to relate pushing and pulling to musculoskeletal disorders.

  11. Quantification of the tug-back by measuring the pulling force and micro computed tomographic evaluation.

    PubMed

    Jeon, Su-Jin; Moon, Young-Mi; Seo, Min-Seock

    2017-11-01

    The aims of this study were to quantify tug-back by measuring the pulling force and investigate the correlation of clinical tug-back pulling force with in vitro gutta-percha (GP) cone adaptation score using micro-computed tomography (µCT). Twenty-eight roots from human single-rooted teeth were divided into 2 groups. In the ProTaper Next (PTN) group, root canals were prepared with PTN, and in the ProFile (PF) group, root canals were prepared using PF ( n = 14). The degree of tug-back was scored after selecting taper-matched GP cones. A novel method using a spring balance was designed to quantify the tug-back by measuring the pulling force. The correlation between tug-back scores, pulling force, and percentage of the gutta-percha occupied area (pGPOA) within apical 3 mm was investigated using µCT. The data were analyzed using Pearson's correlation analysis, one-way analysis of variance (ANOVA) and Tukey's test. Specimens with a strong tug-back had a mean pulling force of 1.24 N (range, 0.15-1.70 N). This study showed a positive correlation between tug-back score, pulling force, and pGPOA. However, there was no significant difference in these factors between the PTN and PF groups. Regardless of the groups, pGPOA and pulling force were significantly higher in the specimens with a higher tug-back score ( p < 0.05). The degree of subjective tug-back was a definitive determinant for master cone adaptation in the root canal. The use of the tug-back scoring system and pulling force allows the interpretation of subjective tug-back in a more objective and quantitative manner.

  12. Collaborative Behavioral Management for Drug-Involved Parolees: Rationale and Design of the Step'n Out Study

    ERIC Educational Resources Information Center

    Friedmann, Peter D.; Katz, Elizabeth C.; Rhodes, Anne G.; Taxman, Faye S.; O'Connell, Daniel J.; Frisman, Linda K.; Burdon, William M.; Fletcher, Bennett W.; Litt, Mark D.; Clarke, Jennifer; Martin, Steven S.

    2008-01-01

    This article describes the rationale, study design, and implementation for the Step'n Out study of the Criminal Justice Drug Abuse Treatment Studies. Step'n Out tests the relative effectiveness of collaborative behavioral management of drug-involved parolees. Collaborative behavioral management integrates the roles of parole officers and treatment…

  13. Postoperative Course and Complications after Pull-through Vaginoplasty for Distal Vaginal Atresia.

    PubMed

    Mansouri, Roshanak; Dietrich, Jennifer E

    2015-12-01

    To report the usual postoperative course and complications after pull-through vaginoplasty for isolated distal vaginal atresia. Retrospective chart review at Texas Children's Hospital of all patients who were diagnosed with isolated distal vaginal atresia and underwent pull-through vaginoplasty during the study time frame. None. Postoperative complications such as vaginal stenosis or infection and postoperative vaginal diameter. Sixteen patients were identified and charts were reviewed. Patients were initially evaluated by pelvic magnetic resonance imaging and found to have distended hematometrocolpos with distal vaginal atresia. All patients underwent pull-through vaginoplasty with similar operative techniques. The average distance from the perineum to the level of the obstruction was 1.84 ± 1.2 cm. Two patients, both with obstructions at greater than 3 cm, experienced stricture formation postoperatively. Four patients (25%) experienced postoperative vaginitis. One patient (6.25%) experienced a postoperative urinary tract infection. Two groups (3 cm or less versus greater than 3 cm) were compared, and the presence of stricture was statistically different based on mean centimeters from perineum prior to pull-through vaginoplasty (P = .038). Distal vaginal atresia is managed with pull-through vaginoplasty. Atresias that extend greater than 3 cm from the perineum are at increased risk for vaginal stricture formation and should be followed to monitor for their formation. Other complications are infrequent and minor. Copyright © 2015 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

  14. Function-Based Modification of Check-In/Check-Out to Influence Escape-Maintained Behavior

    ERIC Educational Resources Information Center

    Kilgus, Stephen P.; Fallon, Lindsay M.; Feinberg, Adam B.

    2016-01-01

    Prior research has suggested Check-In/Check-Out (CICO) effectiveness is linked to the function of problem behavior. Though effective for students whose misbehavior occurs to gain attention, findings are equivocal for behavior that occurs to escape academic tasks. The purpose of this study was to therefore evaluate a modification to CICO, wherein…

  15. Formative Assessment Probes: Pushes and Pulls

    ERIC Educational Resources Information Center

    Keeley, Page

    2011-01-01

    When the concept of force is first taught in the elementary curriculum, it is usually introduced as a push or a pull. The recently released "A Framework for K-12 Science Education" describes grade band endpoints for the Core Idea: Motion and Stability: Forces and Interactions (NRC 2011). It states that by the end of grade 2 students should know…

  16. Fiber-optic push-pull sensor systems

    NASA Technical Reports Server (NTRS)

    Gardner, David L.; Brown, David A.; Garrett, Steven L.

    1991-01-01

    Fiber-optic push-pull sensors are those which exploit the intrinsically differential nature of an interferometer with concommitant benefits in common-mode rejection of undesired effects. Several fiber-optic accelerometer and hydrophone designs are described. Additionally, the recent development at the Naval Postgraduate School of a passive low-cost interferometric signal demodulator permits the development of economical fiber-optic sensor systems.

  17. Optical trapping, pulling, and Raman spectroscopy of airborne absorbing particles based on negative photophoretic force

    NASA Astrophysics Data System (ADS)

    Chen, Gui-hua; He, Lin; Wu, Mu-ying; Yang, Guang; Li, Y. Q.

    2017-08-01

    Optical pulling is the attraction of objects back to the light source by the use of optically induced "negative forces". The light-induced photophoretic force is generated by the momentum transfer between the heating particles and surrounding gas molecules and can be several orders of magnitude larger than the radiation force and gravitation force. Here, we demonstrate that micron-sized absorbing particles can be optically pulled and manipulated towards the light source over a long distance in air with a collimated Gaussian laser beam based on a negative photophoretic force. A variety of airborne absorbing particles can be pulled by this optical pipeline to the region where they are optically trapped with another focused laser beam and their chemical compositions are characterized with Raman spectroscopy. We found that micron-sized particles are pulled over a meter-scale distance in air with a pulling speed of 1-10 cm/s in the optical pulling pipeline and its speed can be controlled by changing the laser intensity. When an aerosol particle is optically trapped with a focused Gaussian beam, we measured its rotation motion around the laser propagation direction and measured its Raman spectroscopy for chemical identification by molecular fingerprints. The centripetal acceleration of the trapped particle as high as 20 times the gravitational acceleration was observed. Optical pulling over large distances with lasers in combination with Raman spectroscopy opens up potential applications for the collection and identification of atmospheric particles.

  18. Sunlight-switchable light shutter fabricated using liquid crystals doped with push-pull azobenzene.

    PubMed

    Oh, Seung-Won; Baek, Jong-Min; Yoon, Tae-Hoon

    2016-11-14

    We propose a sunlight-switchable light shutter using liquid crystal/polymer composite doped with push-pull azobenzene. The proposed light shutter is switchable between the translucent and transparent states by application of an electric field or by UV irradiation. Switching by UV irradiation is based on the change of the liquid crystal (LC) clearing point by the photo-isomerization effect of push-pull azobenzene. Under sunlight, the light shutter can be switched from the translucent to the transparent state by the nematic-isotropic phase transition of the LC domains triggered by trans-cis photo-isomerization of the push-pull azobenzene molecules. When the amount of sunlight is low because of cloud cover or when there is no sunlight at sunset, the light shutter rapidly relaxes from its transparent state back to its initial translucent state by the isotropic-nematic phase transition induced by cis-trans back-isomerization of the push-pull azobenzene molecules.

  19. Pull or Push? Octopuses Solve a Puzzle Problem

    PubMed Central

    Richter, Jonas N.; Hochner, Binyamin; Kuba, Michael J.

    2016-01-01

    Octopuses have large brains and exhibit complex behaviors, but relatively little is known about their cognitive abilities. Here we present data from a five-level learning and problem-solving experiment. Seven octopuses (Octopus vulgaris) were first trained to open an L shaped container to retrieve food (level 0). After learning the initial task all animals followed the same experimental protocol, first they had to retrieve this L shaped container, presented at the same orientation, through a tight fitting hole in a clear Perspex partition (level 1). This required the octopuses to perform both pull and release or push actions. After reaching criterion the animals advanced to the next stage of the test, which would be a different consistent orientation of the object (level 2) at the start of the trial, an opaque barrier (level 3) or a random orientation of the object (level 4). All octopuses were successful in reaching criterion in all levels of the task. At the onset of each new level the performance of the animals dropped, shown as an increase in working times. However, they adapted quickly so that overall working times were not significantly different between levels. Our findings indicate that octopuses show behavioral flexibility by quickly adapting to a change in a task. This can be compared to tests in other species where subjects had to conduct actions comprised of a set of motor actions that cannot be understood by a simple learning rule alone. PMID:27003439

  20. Kinetics of molecular transitions with dynamic disorder in single-molecule pulling experiments

    NASA Astrophysics Data System (ADS)

    Zheng, Yue; Li, Ping; Zhao, Nanrong; Hou, Zhonghuai

    2013-05-01

    Macromolecular transitions are subject to large fluctuations of rate constant, termed as dynamic disorder. The individual or intrinsic transition rates and activation free energies can be extracted from single-molecule pulling experiments. Here we present a theoretical framework based on a generalized Langevin equation with fractional Gaussian noise and power-law memory kernel to study the kinetics of macromolecular transitions to address the effects of dynamic disorder on barrier-crossing kinetics under external pulling force. By using the Kramers' rate theory, we have calculated the fluctuating rate constant of molecular transition, as well as the experimentally accessible quantities such as the force-dependent mean lifetime, the rupture force distribution, and the speed-dependent mean rupture force. Particular attention is paid to the discrepancies between the kinetics with and without dynamic disorder. We demonstrate that these discrepancies show strong and nontrivial dependence on the external force or the pulling speed, as well as the barrier height of the potential of mean force. Our results suggest that dynamic disorder is an important factor that should be taken into account properly in accurate interpretations of single-molecule pulling experiments.

  1. Analytical solutions for efficient interpretation of single-well push-pull tracer tests

    NASA Astrophysics Data System (ADS)

    Huang, Junqi; Christ, John A.; Goltz, Mark N.

    2010-08-01

    Single-well push-pull tracer tests have been used to characterize the extent, fate, and transport of subsurface contamination. Analytical solutions provide one alternative for interpreting test results. In this work, an exact analytical solution to two-dimensional equations describing the governing processes acting on a dissolved compound during a modified push-pull test (advection, longitudinal and transverse dispersion, first-order decay, and rate-limited sorption/partitioning in steady, divergent, and convergent flow fields) is developed. The coupling of this solution with inverse modeling to estimate aquifer parameters provides an efficient methodology for subsurface characterization. Synthetic data for single-well push-pull tests are employed to demonstrate the utility of the solution for determining (1) estimates of aquifer longitudinal and transverse dispersivities, (2) sorption distribution coefficients and rate constants, and (3) non-aqueous phase liquid (NAPL) saturations. Employment of the solution to estimate NAPL saturations based on partitioning and non-partitioning tracers is designed to overcome limitations of previous efforts by including rate-limited mass transfer. This solution provides a new tool for use by practitioners when interpreting single-well push-pull test results.

  2. Frequency pulling in a low-voltage medium-power gyrotron

    NASA Astrophysics Data System (ADS)

    Luo, Li; Du, Chao-Hai; Huang, Ming-Guang; Liu, Pu-Kun

    2018-04-01

    Many recent biomedical applications use medium-power frequency-tunable terahertz (THz) sources, such as sensitivity-enhanced nuclear magnetic resonance, THz imaging, and biomedical treatment. As a promising candidate, a low-voltage gyrotron can generate watt-level, continuous THz-wave radiation. In particular, the frequency-pulling effect in a gyrotron, namely, the effect of the electron beam parameters on the oscillation frequency, can be used to tune the operating frequency. Most previous investigations used complicated and time-consuming gyrotron nonlinear theory to study the influence of many beam parameters on the interaction performance. While gyrotron linear theory investigation demonstrates the advantages of rapidly and clearly revealing the physical influence of individual key beam parameters on the overall system performance, this paper demonstrates systematically the use of gyrotron linear theory to study the frequency-pulling effect in a low-voltage gyrotron with either a Gaussian or a sinusoidal axial-field profile. Furthermore, simulations of a gyrotron operating in the first axial mode are carried out in the framework of nonlinear theory as a contrast. Close agreement is achieved between the two theories. Besides, some interesting results are obtained. In a low-current sinusoidal-profile cavity, the ranges of frequency variation for different axial modes are isolated from each other, and the frequency tuning bandwidth for each axial mode increases by increasing either the beam voltage or pitch factor. Lowering the voltage, the total tuning ranges are squeezed and become concentrated. However, the isolated frequency regions of each axial mode cannot be linked up unless the beam current is increased, meaning that higher current operation is the key to achieving a wider and continuous tuning frequency range. The results presented in this paper can provide a reference for designing a broadband low-voltage gyrotron.

  3. Minimizing pulling geometry errors in atomic force microscope single molecule force spectroscopy.

    PubMed

    Rivera, Monica; Lee, Whasil; Ke, Changhong; Marszalek, Piotr E; Cole, Daniel G; Clark, Robert L

    2008-10-01

    In atomic force microscopy-based single molecule force spectroscopy (AFM-SMFS), it is assumed that the pulling angle is negligible and that the force applied to the molecule is equivalent to the force measured by the instrument. Recent studies, however, have indicated that the pulling geometry errors can drastically alter the measured force-extension relationship of molecules. Here we describe a software-based alignment method that repositions the cantilever such that it is located directly above the molecule's substrate attachment site. By aligning the applied force with the measurement axis, the molecule is no longer undergoing combined loading, and the full force can be measured by the cantilever. Simulations and experimental results verify the ability of the alignment program to minimize pulling geometry errors in AFM-SMFS studies.

  4. An educational intervention to change planned behavior concerning midwife-assisted out-of-hospital childbirth.

    PubMed

    Hans, Jason D; Kimberly, Claire

    2011-01-01

    'The Business of Being Born' is a documentary film that reviews the history, economics, and culture of birth in the United States, with an emphasis on viewing low-risk birth as a natural and reasonably safe experience that does not require medical intervention. A nonequivalent control group design with 468 American university students was used to examine the potential of 'The Business of Being Born' for changing attitudes toward, and planned behavior concerning, midwife-assisted out-of-hospital childbirth. Viewing the film had a large positive effect on planned behavior concerning midwife-assisted out-of-hospital childbirth. Rationales for planned behaviors indicated that trust and safety concerns accounted for the appeal of physician-assisted hospital childbirth over midwife-assisted out-of-hospital childbirth, but that viewing the film substantially tempered these concerns vis-à-vis midwife-assisted out-of-hospital childbirth among a large portion of participants. The results indicate that 'The Business of Being Born' can increase awareness of and support for the midwifery profession, and that these changes may result in increased demand for midwifery services. However, proactive efforts must be taken to ensure that the film reaches its target audience. © 2011 by the American College of Nurse-Midwives.

  5. Micro/nano-mechanical test system employing tensile test holder with push-to-pull transformer

    DOEpatents

    Oh, Yunje; Cyrankowski, Edward; Shan, Zhiwei; Asif, Syed Amanula Syed

    2013-05-07

    A micromachined or microelectromechanical system (MEMS) based push-to-pull mechanical transformer for tensile testing of micro-to-nanometer scale material samples including a first structure and a second structure. The second structure is coupled to the first structure by at least one flexible element that enables the second structure to be moveable relative to the first structure, wherein the second structure is disposed relative to the first structure so as to form a pulling gap between the first and second structures such that when an external pushing force is applied to and pushes the second structure in a tensile extension direction a width of the pulling gap increases so as to apply a tensile force to a test sample mounted across the pulling gap between a first sample mounting area on the first structure and a second sample mounting area on the second structure.

  6. Micro/nano-mechanical test system employing tensile test holder with push-to-pull transformer

    DOEpatents

    Oh, Yunje; Cyrankowski, Edward; Shan, Zhiwei; Syed Asif, Syed Amanula

    2014-07-29

    A micromachined or microelectromechanical system (MEMS) based push-to-pull mechanical transformer for tensile testing of micro-to-nanometer scale material samples including a first structure and a second structure. The second structure is coupled to the first structure by at least one flexible element that enables the second structure to be moveable relative to the first structure, wherein the second structure is disposed relative to the first structure so as to form a pulling gap between the first and second structures such that when an external pushing force is applied to and pushes the second structure in a tensile extension direction a width of the pulling gap increases so as to apply a tensile force to a test sample mounted across the pulling gap between a first sample mounting area on the first structure and a second sample mounting area on the second structure.

  7. Pull-down Assay to Characterize Ca2+/Calmodulin Binding to Plant Receptor Kinases.

    PubMed

    Kaufmann, Christine; Sauter, Margret

    2017-01-01

    Plant receptor-like kinases (RLKs) are regulated by posttranscriptional modification and by interaction with regulatory proteins. A common modification of RLKs is (auto)phosphorylation, and a common regulatory protein is the calcium sensor calmodulin (CaM). We have developed protocols to detect the interaction of an RLK with CaM. The interaction with CaM was shown by bimolecular fluorescence complementation (BiFC) (see Chapter 14) and pull-down assay (this chapter). Both methods offer unique advantages. BiFC is useful in showing interaction of soluble as well as of membrane-bound proteins in planta. Pull-down assays are restricted to soluble proteins and provide in vitro data. The pull-down assay provides the advantage that proteins can be modified prior to binding and that experimental conditions such as the concentration of Ca 2+ or other divalent cations can be controlled. This chapter provides a pull-down protocol to study RLK-CaM interaction with optional steps to investigate the impact of RLK phosphorylation or of Ca 2+ .

  8. Highly water-absorbing silk yarn with interpenetrating network via in situ polymerization.

    PubMed

    Lee, Ka I; Wang, Xiaowen; Guo, Xia; Yung, Ka-Fu; Fei, Bin

    2017-02-01

    Silk was modified via in situ polymerization of two monomers acrylamide and sodium acrylate by swelling in an effective LiBr dissolution system. Swelling of natural silks in LiBr solutions of low concentration was clearly observed under optical microscope, and their conformational changes were revealed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Dissolution tests and FTIR spectra of these modified silks suggested the presence of interpenetrating network of polyacrylamide and poly(sodium acrylate) in the silk yarns. These modified silks exhibited superior water absorption to that of raw silk and greatly improved mechanical properties in both dry and wet states. These novel modified silks also showed low cytotoxicity towards skin keratinocytes, having potential applications in biomedical textiles. This modification method by in situ polymerization after swelling in LiBr provides a new route to highly enhance the properties and performance of silk for various applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Do isometric pull-down exercises increase the acromio-humeral distance?

    PubMed

    Sealey, P; Critchley, D

    2017-06-01

    To evaluate the effect of isometric shoulder extension in 90° shoulder flexion on the acromio-humeral distance, to establish the force required to achieve a clinically important increase in the acromio-humeral distance, and to investigate the practicality and reliability of real-time ultrasound measurement of the acromio-humeral distance in 90° shoulder forward flexion. Prospective single-group intervention. King's College London, Guy's Campus. Twenty healthy volunteers [five males and 15 females (40 shoulders)] with a mean age of 32 (standard deviation 10, range 19 to 55) years were recruited from the faculty and staff at King's College London. The acromio-humeral distance in asymptomatic participants was measured using real-time ultrasound in the neutral position at rest, at 90° shoulder flexion at rest, and while performing an isometric pull-down exercise at 100%, 50%, 30% and 10% maximal voluntary isometric contraction. Real-time ultrasound measures of the acromio-humeral distance. Of the 20 participants, 38 shoulders were imaged. In 90° shoulder flexion, pull-down exercises at all levels of force increased the acromio-humeral distance compared with no pull-down (P<0.05), but this was only clinically significant in males. Measures had excellent short-term intra-operator reliability. Isometric pull-down exercises lead to an increase in the acromio-humeral distance in asymptomatic males that may be clinically important, and therefore may be an appropriate exercise for patients with shoulder pathology. Ultrasound measurement of the acromio-humeral distance in 90° shoulder flexion is practical and reliable. Copyright © 2016 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

  10. Evolution of Pull-Apart Basins and Their Scale Independence

    NASA Astrophysics Data System (ADS)

    Aydin, Atilla; Nur, Amos

    1982-02-01

    Pull-apart basins or rhomb grabens and horsts along major strike-slip fault systems in the world are generally associated with horizontal slip along faults. A simple model suggests that the width of the rhombs is controlled by the initial fault geometry, whereas the length increases with increasing fault displacement. We have tested this model by analyzing the shapes of 70 well-defined rhomb-like pull-apart basins and pressure ridges, ranging from tens of meters to tens of kilometers in length, associated with several major strike-slip faults in the western United States, Israel, Turkey, Iran, Guatemala, Venezuela, and New Zealand. In conflict with the model, we find that the length to width ratio of these basins is a constant value of approximately 3; these basins become wider as they grow longer with increasing fault offset. Two possible mechanisms responsible for the increase in width are suggested: (1) coalescence of neighboring rhomb grabens as each graben increases its length and (2) formation of fault strands parallel to the existing ones when large displacements need to be accommodated. The processes of formation and growth of new fault strands promote interaction among the new faults and between the new and preexisting faults on a larger scale. Increased displacement causes the width of the fault zone to increase resulting in wider pull-apart basins.

  11. Optical Pulling and Pushing Forces in Bilayer P T -Symmetric Structures

    NASA Astrophysics Data System (ADS)

    Alaee, Rasoul; Christensen, Johan; Kadic, Muamer

    2018-01-01

    We investigate the optical force exerted on a parity-time-symmetric bilayer made of balanced gain and loss. We show that an asymmetric optical pulling or pushing force can be exerted on this system depending on the direction of impinging light. The optical pulling or pushing force has a direct physical link to the optical characteristics embedded in the non-Hermitian bilayer. Furthermore, we suggest taking advantage of the optically generated asymmetric force to launch vibrations of an arbitrary shape, which is useful for the contactless probing of mechanical deformations.

  12. Finger-attachment device for the feedback of gripping and pulling force in a manipulating system for brain tumor resection.

    PubMed

    Chinbe, Hiroyuki; Yoneyama, Takeshi; Watanabe, Tetsuyou; Miyashita, Katsuyoshi; Nakada, Mitsutoshi

    2018-01-01

    Development and evaluation of an effective attachment device for a bilateral brain tumor resection robotic surgery system based on the sensory performance of the human index finger in order to precisely detect gripping- and pulling-force feedback. First, a basic test was conducted to investigate the performance of the human index finger in the gripping- and pulling-force feedback system. Based on the test result, a new finger-attachment device was designed and constructed. Then, discrimination tests were conducted to assess the pulling force and the feedback on the hardness of the gripped material. The results of the basic test show the application of pulling force on the side surface of the finger has an advantage to distinguish the pulling force when the gripping force is applied on the finger-touching surface. Based on this result, a finger-attachment device that applies a gripping force on the finger surface and pulling force on the side surface of the finger was developed. By conducting a discrimination test to assess the hardness of the gripped material, an operator can distinguish whether the gripped material is harder or softer than a normal brain tissue. This will help in confirming whether the gripped material is a tumor. By conducting a discrimination test to assess the pulling force, an operator can distinguish the pulling-force resistance when attempting to pull off the soft material. Pulling-force feedback may help avoid the breaking of blood pipes when they are trapped in the gripper or attached to the gripped tissue. The finger-attachment device that was developed for detecting gripping- and pulling-force feedback may play an important role in the development of future neurosurgery robotic systems for precise and safe resection of brain tumors.

  13. O2 Plasma Etching and Antistatic Gun Surface Modifications for CNT Yarn Microelectrode Improve Sensitivity and Antifouling Properties.

    PubMed

    Yang, Cheng; Wang, Ying; Jacobs, Christopher B; Ivanov, Ilia N; Venton, B Jill

    2017-05-16

    Carbon nanotube (CNT) based microelectrodes exhibit rapid and selective detection of neurotransmitters. While different fabrication strategies and geometries of CNT microelectrodes have been characterized, relatively little research has investigated ways to selectively enhance their electrochemical properties. In this work, we introduce two simple, reproducible, low-cost, and efficient surface modification methods for carbon nanotube yarn microelectrodes (CNTYMEs): O 2 plasma etching and antistatic gun treatment. O 2 plasma etching was performed by a microwave plasma system with oxygen gas flow and the optimized time for treatment was 1 min. The antistatic gun treatment flows ions by the electrode surface; two triggers of the antistatic gun was the optimized number on the CNTYME surface. Current for dopamine at CNTYMEs increased 3-fold after O 2 plasma etching and 4-fold after antistatic gun treatment. When the two treatments were combined, the current increased 12-fold, showing the two effects are due to independent mechanisms that tune the surface properties. O 2 plasma etching increased the sensitivity due to increased surface oxygen content but did not affect surface roughness while the antistatic gun treatment increased surface roughness but not oxygen content. The effect of tissue fouling on CNT yarns was studied for the first time, and the relatively hydrophilic surface after O 2 plasma etching provided better resistance to fouling than unmodified or antistatic gun treated CNTYMEs. Overall, O 2 plasma etching and antistatic gun treatment improve the sensitivity of CNTYMEs by different mechanisms, providing the possibility to tune the CNTYME surface and enhance sensitivity.

  14. 25 CFR 542.8 - What are the minimum internal control standards for pull tabs?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the accuracy of the ending balance in the pull tab control by reconciling the pull tabs on hand. (6) A.... (g) Standards for statistical reports. (1) Records shall be maintained, which include win, write (sales), and a win-to-write hold percentage as compared to the theoretical hold percentage derived from...

  15. Deformation Behavior during Processing in Carbon Fiber Reinforced Plastics

    NASA Astrophysics Data System (ADS)

    Ogihara, Shinji; Kobayashi, Satoshi

    In this study, we manufacture the device for measuring the friction between the prepreg curing process and subjected to pull-out tests with it The prepreg used in this study is a unidirectional carbon/epoxy, produced by TORAY designation of T700SC/2592.When creating specimens 4-ply prepregs are prepared and laminated. The 2-ply prepregs in the middle are shifted 50mm. In order to measure the friction between the prepreg during the cure process, we simulate the environment in the autoclave in the device, and we experiment in pull-out test. Test environment simulating temperature and pressure. The speed of displacement should be calculated by coefficient of thermal expansions (CTE). By calculation, 0.05mm/min gives the order of magnitude of displacement speed. In this study, 3 pull-out speeds are used: 0.01, 0.05 and 0.1mm/min. The specimen was heated by a couple of heaters, and we controlled the heaters with a temperature controller along the curing conditions of the prepreg. We put pressure using 4 bolts. Two strain gages were put on the bolt. We can understand the load applied to the specimen from the strain of the bolt. Pressure was adjusted the tightness of the bolt according to curing conditions. By using such a device, the pull-out test performed by tensile testing machine while adding temperature and pressure. During the 5 hours, we perform experiments while recording the load and stroke. The shear stress determined from the load and the stroke, and evaluated.

  16. Acquisition and Tracking Behavior of Phase-Locked Loops

    NASA Technical Reports Server (NTRS)

    Viterbi, A. J.

    1958-01-01

    Phase-locked or APC loops have found increasing applications in recent years as tracking filters, synchronizing devices, and narrowband FM discriminators. Considerable work has been performed to determine the noise-squelching properties of the loop when it is operating in or near phase lock and is functioning as a linear coherent detector. However, insufficient consideration has been devoted to the non-linear behavior of the loop when it is out of lock and in the process of pulling in. Experimental evidence has indicated that there is a strong tendency for phase-locked loops to achieve lock under most circumstances. However, the analysis which has appeared in the literature iis limited to the acquisition of a constant frequency reference signal with only one phase-locked loop filter configuration. This work represents an investigation of frequency acquisition properties of phase-locked loops for a variety of reference-signal behavior and loop configurations

  17. Pulse width modulated push-pull driven parallel resonant converter with active free-wheel

    DOEpatents

    Reass, William A.; Schrank, Louis

    2004-06-22

    An apparatus and method for high frequency alternating power generation to control kilowatts of supplied power in microseconds. The present invention includes a means for energy storage, push-pull switching means, control electronics, transformer means, resonant circuitry and means for excess energy recovery, all in electrical communication. A push-pull circuit works synchronously with a force commutated free-wheel transistor to provide current pulses to a transformer. A change in the conduction angle of the push-pull circuit changes the amount of energy coupled into the transformer's secondary oscillating circuit, thereby altering the induced secondary resonating voltage. At the end of each pulse, the force commutated free-wheel transistor causes residual excess energy in the primary circuit to be transmitted back to the storage capacitor for later use.

  18. Phase inverter provides variable reference push-pull output

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Dual-transistor difference amplifier provides a push-pull output referenced to a dc potential which can be varied without affecting the signal levels. The amplifier is coupled with a feedback circuit which can vary the operating points of the transistors by equal amounts to provide the variable reference potentials.

  19. Movement Suppression Time-Out for Undesirable Behavior in Psychotic and Severely Developmentally Delayed Children.

    ERIC Educational Resources Information Center

    Rolider, Ahmos; Van Houten, Ron

    1985-01-01

    Effects of a movement suppression time-out, which involved punishing any movements or verbalization while a client is in the time-out area, were evaluated in four experiments. The procedure produced a larger reduction in the target behavior in all three children and effectiveness was explained in terms of suppression of self-stimulation during…

  20. The Effect of Coconut Oil pulling on Streptococcus mutans Count in Saliva in Comparison with Chlorhexidine Mouthwash.

    PubMed

    Kaushik, Mamta; Reddy, Pallavi; Sharma, Roshni; Udameshi, Pooja; Mehra, Neha; Marwaha, Aditya

    2016-01-01

    Oil pulling is an age-old practice that has gained modern popularity in promoting oral and systemic health. The scientific verification for this practice is insufficient. Thus, this study evaluated the effect of coconut oil pulling on the count of Streptococcus mutans in saliva and to compare its efficacy with that of Chlorhexidine mouthwash: in vivo. The null hypothesis was that coconut oil pulling has no effect on the bacterial count in saliva. A randomized controlled study was planned and 60 subjects were selected. The subjects were divided into three groups, Group A: Oil pulling, Group B: Chlorhexidine, and Group C: Distilled water. Group A subjects rinsed mouth with 10 ml of coconut oil for 10 minutes. Group B subjects rinsed mouth with 5 ml Chlorhexidine mouthwash for 1 minute and Group C with 5 ml distilled water for 1 minute in the morning before brushing. Saliva samples were collected and cultured on 1st day and after 2 weeks from all subjects. Colonies were counted to compare the efficacy of coconut oil and Chlorhexidine with distilled water. Statistically significant reduction in S. mutans count was seen in both the coconut oil pulling and Chlorhexidine group. Oil pulling can be explored as a safe and effective alternative to Chlorhexidine. Edible oil-pulling therapy is natural, safe and has no side effects. Hence, it can be considered as a preventive therapy at home to maintain oral hygiene.

  1. Causal assessment of occupational pushing or pulling and low back pain: results of a systematic review.

    PubMed

    Roffey, Darren M; Wai, Eugene K; Bishop, Paul; Kwon, Brian K; Dagenais, Simon

    2010-06-01

    Low back pain (LBP) is a prevalent and expensive musculoskeletal condition that predominantly occurs in working-age individuals of industrialized nations. Although numerous occupational physical activities have been implicated in its etiology, determining the causation of occupational LBP still remains a challenge. To conduct a systematic review evaluating the causal relationship between occupational pushing or pulling and LBP. Systematic review of the literature. Studies reporting an association between occupational pushing or pulling and LBP. Numerical association between exposure to pushing or pulling and the presence of LBP. A systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford-Hill criteria for causation for occupational pushing or pulling and LBP. A search was conducted using Medline, EMBASE, CINAHL, Cochrane Library, and OSH-ROM, gray literature, hand-searching occupational health journals, reference lists of included studies, and expert knowledge. Methodological quality was assessed using a modified Newcastle-Ottawa Scale. This search yielded 2,766 citations. Thirteen studies met the inclusion criteria. Eight were high-quality studies and five were low-quality studies. There was conflicting evidence with one high-quality study demonstrating a positive association between occupational pushing or pulling and LBP and five studies showing no relationship. One study reported a nonstatistically significant dose-response trend, four studies discussed temporality of which one indicated a positive finding, two studies discussed the biological plausibility of a causal link between occupational pushing or pulling and LBP, and no evidence was uncovered to assess the experiment criterion. A qualitative summary of existing studies was not able to find any high-quality studies that fully satisfied any of the Bradford-Hill causation criteria for occupational pushing or

  2. Investigation of the influence of coolant-lubricant modification on selected effects of pull broaching

    NASA Astrophysics Data System (ADS)

    Adamczuk, Krzysztof; Legutko, Stanisław; Laber, Alicja; Serwa, Wojciech

    2017-10-01

    The paper presents the results of testing the wear of the tool (pull broach) and a gear wheel splineway surface roughness after the friction node of pull broach/gear wheel (CuSn12Ni2) had been lubricated with metal machining oil and the same oil modified with chemically active exploitation additive. To designate the influence of modifying metal machining oil by the exploitation additive on the lubricating properties, anti-wear and antiseizure indicators have been appointed. Exploitation tests have proved purposefulness of modifying metal machining oil. Modification of the lubricant has contributed to reduction of the wear of the tools - pull broaches and to reduction of roughness of the splineway surfaces.

  3. Assessment of the Teaching Behavior of the Instructors of an Out-of-School Program

    ERIC Educational Resources Information Center

    Rodríguez-Naveiras, Elena; Borges, África

    2015-01-01

    Out-of-school programs for students with high abilities are especially relevant when their needs are not covered in formal education. The evaluation of these programs is essential and it can be carried out from different evaluative approaches. The evaluation of the behavior of the people who implement the programs is an important aspect in the…

  4. Effects of van der Waals Force and Thermal Stresses on Pull-in Instability of Clamped Rectangular Microplates.

    PubMed

    Batra, Romesh C; Porfiri, Maurizio; Spinello, Davide

    2008-02-15

    We study the influence of von Karman nonlinearity, van der Waals force, and a athermal stresses on pull-in instability and small vibrations of electrostatically actuated mi-croplates. We use the Galerkin method to develop a tractable reduced-order model for elec-trostatically actuated clamped rectangular microplates in the presence of van der Waals forcesand thermal stresses. More specifically, we reduce the governing two-dimensional nonlineartransient boundary-value problem to a single nonlinear ordinary differential equation. For thestatic problem, the pull-in voltage and the pull-in displacement are determined by solving apair of nonlinear algebraic equations. The fundamental vibration frequency corresponding toa deflected configuration of the microplate is determined by solving a linear algebraic equa-tion. The proposed reduced-order model allows for accurately estimating the combined effectsof van der Waals force and thermal stresses on the pull-in voltage and the pull-in deflectionprofile with an extremely limited computational effort.

  5. Effects of van der Waals Force and Thermal Stresses on Pull-in Instability of Clamped Rectangular Microplates

    PubMed Central

    Batra, Romesh C.; Porfiri, Maurizio; Spinello, Davide

    2008-01-01

    We study the influence of von Kármán nonlinearity, van der Waals force, and thermal stresses on pull-in instability and small vibrations of electrostatically actuated microplates. We use the Galerkin method to develop a tractable reduced-order model for electrostatically actuated clamped rectangular microplates in the presence of van der Waals forces and thermal stresses. More specifically, we reduce the governing two-dimensional nonlinear transient boundary-value problem to a single nonlinear ordinary differential equation. For the static problem, the pull-in voltage and the pull-in displacement are determined by solving a pair of nonlinear algebraic equations. The fundamental vibration frequency corresponding to a deflected configuration of the microplate is determined by solving a linear algebraic equation. The proposed reduced-order model allows for accurately estimating the combined effects of van der Waals force and thermal stresses on the pull-in voltage and the pull-in deflection profile with an extremely limited computational effort. PMID:27879752

  6. 25 CFR 543.9 - What are the minimum internal control standards for pull tabs?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false What are the minimum internal control standards for pull tabs? 543.9 Section 543.9 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR HUMAN SERVICES MINIMUM INTERNAL CONTROL STANDARDS FOR CLASS II GAMING § 543.9 What are the minimum internal control standards for pull tabs? (a)...

  7. 25 CFR 542.8 - What are the minimum internal control standards for pull tabs?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false What are the minimum internal control standards for pull tabs? 542.8 Section 542.8 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR HUMAN SERVICES MINIMUM INTERNAL CONTROL STANDARDS § 542.8 What are the minimum internal control standards for pull tabs? (a) Computer applications. For...

  8. 25 CFR 543.9 - What are the minimum internal control standards for pull tabs?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false What are the minimum internal control standards for pull tabs? 543.9 Section 543.9 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR HUMAN SERVICES MINIMUM INTERNAL CONTROL STANDARDS FOR CLASS II GAMING § 543.9 What are the minimum internal control standards for pull tabs? (a)...

  9. 25 CFR 542.8 - What are the minimum internal control standards for pull tabs?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false What are the minimum internal control standards for pull tabs? 542.8 Section 542.8 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR HUMAN SERVICES MINIMUM INTERNAL CONTROL STANDARDS § 542.8 What are the minimum internal control standards for pull tabs? (a) Computer applications. For...

  10. 25 CFR 542.8 - What are the minimum internal control standards for pull tabs?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false What are the minimum internal control standards for pull tabs? 542.8 Section 542.8 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR HUMAN SERVICES MINIMUM INTERNAL CONTROL STANDARDS § 542.8 What are the minimum internal control standards for pull tabs? (a) Computer applications. For...

  11. Optical pulling of airborne absorbing particles and smut spores over a meter-scale distance with negative photophoretic force

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

    Lin, Jinda; Hart, Adam G.; Li, Yong-qing, E-mail: liy@ecu.edu

    2015-04-27

    We demonstrate optical pulling of single light-absorbing particles and smut spores in air over a meter-scale distance using a single collimated laser beam based on negative photophoretic force. The micron-sized particles are pulled towards the light source at a constant speed of 1–10 cm/s in the optical pulling pipeline while undergoing transverse rotation at 0.2–10 kHz. The pulled particles can be manipulated and precisely positioned on the entrance window with an accuracy of ∼20 μm, and their chemical compositions can be characterized with micro-Raman spectroscopy.

  12. Pull-out testing facility for geosynthetics.

    DOT National Transportation Integrated Search

    1992-11-01

    The considerable increase in using geosynthetics in soil reinforcement made it necessary to develop methods of measuring the interaction properties and modeling load transfer in reinforced-soil structures. The large number of factors that influence t...

  13. Outdoor Education Units. Pull Out Feature.

    ERIC Educational Resources Information Center

    Levi, Jan

    2001-01-01

    Briefly presents 15 outdoor education units covering orienteering, map reading, safety, rescue, rope skills, first aid, camping, kayaking, rock and wall climbing, caving, survival skills, sailing, hiking, and outdoor equipment. Each unit has a brief description, including the knowledge and skills that students should be able to demonstrate. (TD)

  14. Application of a hybrid Electrocoagulation-Fenton process in yarn dye wastewater: Kinetic study

    NASA Astrophysics Data System (ADS)

    Riadi, L.; Sapei, L.; Lidiawati, T.; Agustin, Y. E.

    2016-11-01

    Reactive dyes contain a significant portion of colorants used in yarn dying process and also in textile industry. Since the COD content is usually high in such wastewater,we conducted a hybrid electrocoagulation-fenton method to treat the wastewater. This work describes the application of the hybrid system to the removal of chemical oxygen demand and color from the wastewater in a batch reactor. Having worked with initial pH of 3,0; temperature at 30°C, molar ratio of Fe2+/H2O2 =1/10 and the mol ratio H2O2/COD = 4, we got 88.3% COD conversion and 88.5% color removal. The COD degradation process can be explained in two phases, the first phase is instantaneous reaction and the second phase is first order reaction. The kinetic constant was 0.0053 minute-1 and the rate of COD degradation was 0.0053[COD] mg/L minute.

  15. Visual pop-out in barn owls: Human-like behavior in the avian brain.

    PubMed

    Orlowski, Julius; Beissel, Christian; Rohn, Friederike; Adato, Yair; Wagner, Hermann; Ben-Shahar, Ohad

    2015-01-01

    Visual pop-out is a phenomenon by which the latency to detect a target in a scene is independent of the number of other elements, the distractors. Pop-out is an effective visual-search guidance that occurs typically when the target is distinct in one feature from the distractors, thus facilitating fast detection of predators or prey. However, apart from studies on primates, pop-out has been examined in few species and demonstrated thus far in rats, archer fish, and pigeons only. To fill this gap, here we study pop-out in barn owls. These birds are a unique model system for such exploration because their lack of eye movements dictates visual behavior dominated by head movements. Head saccades and interspersed fixation periods can therefore be tracked and analyzed with a head-mounted wireless microcamera--the OwlCam. Using this methodology we confronted two owls with scenes containing search arrays of one target among varying numbers (15-63) of similar looking distractors. We tested targets distinct either by orientation (Experiment 1) or luminance contrast (Experiment 2). Search time and the number of saccades until the target was fixated remained largely independent of the number of distractors in both experiments. This suggests that barn owls can exhibit pop-out during visual search, thus expanding the group of species and brain structures that can cope with this fundamental visual behavior. The utility of our automatic analysis method is further discussed for other species and scientific questions.

  16. Fast Pulling of n-Type Si Ingots for Enhanced Si Solar Cell Production

    NASA Astrophysics Data System (ADS)

    Kim, Kwanghun; Park, Sanghyun; Park, Jaechang; Pang, Ilsun; Ryu, Sangwoo; Oh, Jihun

    2018-07-01

    Reducing the manufacturing costs of silicon substrates is an important issue in the silicon-based solar cell industry. In this study, we developed a high-throughput ingot growth method by accelerating the pulling speed in the Czochralski process. By controlling the heat flow of the ingot growth chamber and at the solid-liquid interfaces, the pulling speed of an ingot could be increased by 15% compared to the conventional method, while retaining high quality. The wafer obtained at a high pulling speed showed an enhanced minority carrier lifetime compared with conventional wafers, due to the vacancy passivation effect, and also demonstrated comparable bulk resistivity and impurities. The results in this work are expected to open a new way to enhance the productivity of Si wafers used for Si solar cells, and therefore, to reduce the overall manufacturing cost.

  17. Fast Pulling of n-Type Si Ingots for Enhanced Si Solar Cell Production

    NASA Astrophysics Data System (ADS)

    Kim, Kwanghun; Park, Sanghyun; Park, Jaechang; Pang, Ilsun; Ryu, Sangwoo; Oh, Jihun

    2018-03-01

    Reducing the manufacturing costs of silicon substrates is an important issue in the silicon-based solar cell industry. In this study, we developed a high-throughput ingot growth method by accelerating the pulling speed in the Czochralski process. By controlling the heat flow of the ingot growth chamber and at the solid-liquid interfaces, the pulling speed of an ingot could be increased by 15% compared to the conventional method, while retaining high quality. The wafer obtained at a high pulling speed showed an enhanced minority carrier lifetime compared with conventional wafers, due to the vacancy passivation effect, and also demonstrated comparable bulk resistivity and impurities. The results in this work are expected to open a new way to enhance the productivity of Si wafers used for Si solar cells, and therefore, to reduce the overall manufacturing cost.

  18. Pick-N-Pull Auto Dismantlers, Kansas City, LLC Inc.

    EPA Pesticide Factsheets

    The EPA is providing notice of a proposed Administrative Penalty Assessment against Pick-N-Pull Auto Dismantlers, Kansas City, LLC, a subsidiary of Schnitzer Steel Industries, Inc., for alleged violations at its facilities at 8012 East Truman Rd., Kansas C

  19. Micro-pulling-down furnace modification and single crystal fibers growth

    NASA Astrophysics Data System (ADS)

    Yuan, Dongsheng; Jia, Zhitai; Li, Yang; Wu, Baiyi; Tao, Xutang

    2016-03-01

    Single crystal fiber (SCF) combines the excellent instinct properties of conventional bulk laser crystals, and the special geometry advantage of active optical fibers. YAG and LuAG are proper host candidates for single crystal fiber laser with high thermal conductivity. Despite a lower thermal conductivity for pure crystal than YAG, LuAG crystal is easier to obtain homogeneous optical quality, and has a thermal conductivity nearly independent from the doping level. Micropulling- down (μ-PD) has relatively small thermal gradient, and here we use μ-PD to carry out high quality SCFs. Through the μ-PD furnace manufactured by ourselves, crystal fibers with different diameters have been grown successfully. We designed and fabricated a method to adjust the thermal distribution, and with the favor of pulling-down rate, the specific diameter can be controlled perfectly. The crystalline quality and homogeneity along the whole fiber were investigated, and LuAG SCF was confirmed to have a fine crystal quality for laser.

  20. Additive Manufacturing of Multifunctional Components Using High Density Carbon Nanotube Yarn Filaments

    NASA Technical Reports Server (NTRS)

    Gardner, John M.; Sauti, Godfrey; Kim, Jae-Woo; Cano, Roberto J.; Wincheski, Russell A.; Stelter, Christopher J.; Grimsley, Brian W.; Working, Dennis C.; Siochi, Emilie J.

    2016-01-01

    Additive manufacturing allows for design freedom and part complexity not currently attainable using traditional manufacturing technologies. Fused Filament Fabrication (FFF), for example, can yield novel component geometries and functionalities because the method provides a high level of control over material placement and processing conditions. This is achievable by extrusion of a preprocessed filament feedstock material along a predetermined path. However if fabrication of a multifunctional part relies only on conventional filament materials, it will require a different material for each unique functionality printed into the part. Carbon nanotubes (CNTs) are an attractive material for many applications due to their high specific strength as well as good electrical and thermal conductivity. The presence of this set of properties in a single material presents an opportunity to use one material to achieve multifunctionality in an additively manufactured part. This paper describes a recently developed method for processing continuous CNT yarn filaments into three-dimensional articles, and summarizes the mechanical, electrical, and sensing performance of the components fabricated in this way.

  1. Actomyosin Pulls to Advance the Nucleus in a Migrating Tissue Cell

    PubMed Central

    Wu, Jun; Kent, Ian A.; Shekhar, Nandini; Chancellor, T.J.; Mendonca, Agnes; Dickinson, Richard B.; Lele, Tanmay P.

    2014-01-01

    The cytoskeletal forces involved in translocating the nucleus in a migrating tissue cell remain unresolved. Previous studies have variously implicated actomyosin-generated pushing or pulling forces on the nucleus, as well as pulling by nucleus-bound microtubule motors. We found that the nucleus in an isolated migrating cell can move forward without any trailing-edge detachment. When a new lamellipodium was triggered with photoactivation of Rac1, the nucleus moved toward the new lamellipodium. This forward motion required both nuclear-cytoskeletal linkages and myosin activity. Apical or basal actomyosin bundles were found not to translate with the nucleus. Although microtubules dampen fluctuations in nuclear position, they are not required for forward translocation of the nucleus during cell migration. Trailing-edge detachment and pulling with a microneedle produced motion and deformation of the nucleus suggestive of a mechanical coupling between the nucleus and the trailing edge. Significantly, decoupling the nucleus from the cytoskeleton with KASH overexpression greatly decreased the frequency of trailing-edge detachment. Collectively, these results explain how the nucleus is moved in a crawling fibroblast and raise the possibility that forces could be transmitted from the front to the back of the cell through the nucleus. PMID:24411232

  2. Cavity Pull Rod: Device to Promote Single Crystal Growth from the Melt

    NASA Technical Reports Server (NTRS)

    Goldsby, Jon (Inventor)

    2017-01-01

    A pull rod for use in producing a single crystal from a molten alloy is provided that includes an elongated rod having a first end and a second end, a first cavity defined at the first end and a second cavity defined at the first end and in communication with the first cavity. The first cavity receives the molten alloy and the second cavity vents a gas from the molten alloy to thereby template a single crystal when the pull rod is dipped into and extracted from the molten alloy.

  3. Trunk response and stability in standing under sagittal-symmetric pull-push forces at different orientations, elevations and magnitudes.

    PubMed

    El Ouaaid, Z; Shirazi-Adl, A; Plamondon, A

    2018-03-21

    To reduce lifting and associated low back injuries, manual material handling operations often involve pulling-pushing of carts at different weights, orientations, and heights. The loads on spine and risk of injury however need to be investigated. The aim of this study was to evaluate muscle forces, spinal loads and trunk stability in pull-push tasks in sagittal-symmetric, static upright standing posture. Three hand-held load magnitudes (80, 120 and 160 N) at four elevations (0, 20, 40 and 60 cm to the L5-S1) and 24 force directions covering all pull/push orientations were considered. For this purpose, a musculoskeletal finite element model with kinematics measured earlier were used. Results demonstrated that peak spinal forces occur under inclined pull (lift) at upper elevations but inclined push at the lowermost one. Minimal spinal loads, on the other hand, occurred at and around vertical pull directions. Overall, spinal forces closely followed variations in the net external moment of pull-push forces at the L5-S1. Local lumbar muscles were most active in pulls while global extensor muscles in lifts. The trunk stability margin decreased with load elevation except at and around horizontal push; it peaked under pulls and reached minimum at vertical lifts. It also increased with antagonist activity in muscles and intra-abdominal pressure. Results provide insight into the marked effects of variation in the load orientation and elevation on muscle forces, spinal loads and trunk stability and hence offer help in rehabilitation, performance enhancement training and design of safer workplaces. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Push-Pull Effects of Three Plant Secondary Metabolites on Oviposition of the Potato Tuber Moth, Phthorimaea operculella

    PubMed Central

    Ma, Y.F.; Xiao, C.

    2013-01-01

    The push-pull effects of three plant secondary metabolites, azadirachtin, eucalyptol, and heptanal, on the oviposition choices of potato tubers by the potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) were tested in the laboratory. Azadirachtin at concentrations from 1.5 to 12 mg/L had a significant repellent effect on oviposition. Eucalyptol at concentrations from 3 to 12 mg/L promoted oviposition. Heptanal promoted oviposition at low concentrations from 0.1875 to 3.0 mg/L but repelled it at higher concentrations from 12 to 24 mg/L. The combination of azadirachtin (12 mg/L) with eucalyptol (3.0 mg/L) resulted in a significant pushpull effect of 56.3% on oviposition. The average maximum push-pull effects occurred with the combinations of azadirachtin with heptanal (12 and 0.375 mg/L, respectively; 38.7% push-pull effect), heptanal with eucalyptol (12 and 6 mg/L, respectively; 31.4% push-pull effect), and heptanal (high concentration) with heptanal (low concentration) (12.0 and 0.375 mg/L, respectively; 25% push-pull effect). PMID:24786822

  5. Slab-pull and slab-push earthquakes in the Mexican, Chilean and Peruvian subduction zones

    NASA Astrophysics Data System (ADS)

    Lemoine, A.; Madariaga, R.; Campos, J.

    2002-09-01

    We studied intermediate depth earthquakes in the Chile, Peru and Mexican subduction zones, paying special attention to slab-push (down-dip compression) and slab-pull (down-dip extension) mechanisms. Although, slab-push events are relatively rare in comparison with slab-pull earthquakes, quite a few have occurred recently. In Peru, a couple slab-push events occurred in 1991 and one slab-pull together with several slab-push events occurred in 1970 near Chimbote. In Mexico, several slab-push and slab-pull events occurred near Zihuatanejo below the fault zone of the 1985 Michoacan event. In central Chile, a large M=7.1 slab-push event occurred in October 1997 that followed a series of four shallow Mw>6 thrust earthquakes on the plate interface. We used teleseismic body waveform inversion of a number of Mw>5.9 slab-push and slab-pull earthquakes in order to obtain accurate mechanisms, depths and source time functions. We used a master event method in order to get relative locations. We discussed the occurrence of the relatively rare slab-push events in the three subduction zones. Were they due to the geometry of the subduction that produces flexure inside the downgoing slab, or were they produced by stress transfer during the earthquake cycle? Stress transfer can not explain the occurence of several compressional and extensional intraplate intermediate depth earthquakes in central Chile, central Mexico and central Peru. It seemed that the heterogeneity of the stress field produced by complex slab geometry has an important influence on intraplate intermediate depth earthquakes.

  6. Push-pull tests for estimating effective porosity: expanded analytical solution and in situ application

    NASA Astrophysics Data System (ADS)

    Paradis, Charles J.; McKay, Larry D.; Perfect, Edmund; Istok, Jonathan D.; Hazen, Terry C.

    2018-03-01

    The analytical solution describing the one-dimensional displacement of the center of mass of a tracer during an injection, drift, and extraction test (push-pull test) was expanded to account for displacement during the injection phase. The solution was expanded to improve the in situ estimation of effective porosity. The truncated equation assumed displacement during the injection phase was negligible, which may theoretically lead to an underestimation of the true value of effective porosity. To experimentally compare the expanded and truncated equations, single-well push-pull tests were conducted across six test wells located in a shallow, unconfined aquifer comprised of unconsolidated and heterogeneous silty and clayey fill materials. The push-pull tests were conducted by injection of bromide tracer, followed by a non-pumping period, and subsequent extraction of groundwater. The values of effective porosity from the expanded equation (0.6-5.0%) were substantially greater than from the truncated equation (0.1-1.3%). The expanded and truncated equations were compared to data from previous push-pull studies in the literature and demonstrated that displacement during the injection phase may or may not be negligible, depending on the aquifer properties and the push-pull test parameters. The results presented here also demonstrated the spatial variability of effective porosity within a relatively small study site can be substantial, and the error-propagated uncertainty of effective porosity can be mitigated to a reasonable level (< ± 0.5%). The tests presented here are also the first that the authors are aware of that estimate, in situ, the effective porosity of fine-grained fill material.

  7. Anomalous Transport in Single-Well Push-Pull Tracer Tests

    NASA Astrophysics Data System (ADS)

    Chen, K.; Zhan, H.

    2016-12-01

    Single-Well Push-Pull (SWPP) tracer test was conducted to estimate the hydraulic and transport properties in a fractured aquifer at Newark basin. A common phenomenon observed for a set of SWPP tests with different incubation time is the heavy tailing of breakthrough curve (BTC) in pumping phase. A novel model with fractional-in-time and (or) -space was developed to interpret the anomalous transport behavior in SWPP tests. The fractal models, including fractional-in-time, fractional-in-space and fractional-in-time-and-space, were solved in radial coordinate using implicit Euler method. A semi-analytical solution of the mobile-immobile (MIM) model was derived as well for comparison purpose. It is found that the fractional-in-space and fractional-in-time-and-space models match the experimental data well. The BTC of the MIM model drops slower than that of the fractional-in-space model at the beginning of pumping and drops much faster at late time. The best match of fractional-in-space model with the experimental data demonstrates that the non-local transport in space plays an important role in SWPP tests conducted in fractured aquifers.

  8. Push pull microfluidics on a multi-level 3D CD.

    PubMed

    Thio, Tzer Hwai Gilbert; Ibrahim, Fatimah; Al-Faqheri, Wisam; Moebius, Jacob; Khalid, Noor Sakinah; Soin, Norhayati; Kahar, Maria Kahar Bador Abdul; Madou, Marc

    2013-08-21

    A technique known as thermo-pneumatic (TP) pumping is used to pump fluids on a microfluidic compact disc (CD) back towards the CD center against the centrifugal force that pushes liquids from the center to the perimeter of the disc. Trapped air expands in a TP air chamber during heating, and this creates positive pressure on liquids located in chambers connected to that chamber. While the TP air chamber and connecting channels are easy to fabricate in a one-level CD manufacturing technique, this approach provides only one way pumping between two chambers, is real-estate hungry and leads to unnecessary heating of liquids in close proximity to the TP chamber. In this paper, we present a novel TP push and pull pumping method which allows for pumping of liquid in any direction between two connected liquid chambers. To ensure that implementation of TP push and pull pumping also addresses the issue of space and heating challenges, a multi-level 3D CD design is developed, and localized forced convection heating, rather than infra-red (IR) is applied. On a multi-level 3D CD, the TP features are placed on a top level separate from the rest of the microfluidic processes that are implemented on a lower separate level. This approach allows for heat shielding of the microfluidic process level, and efficient usage of space on the CD for centrifugal handling of liquids. The use of localized forced convection heating, rather than infra-red (IR) or laser heating in earlier implementations allows not only for TP pumping of liquids while the CD is spinning but also makes heat insulation for TP pumping and other fluidic functions easier. To aid in future implementations of TP push and pull pumping on a multi-level 3D CD, study on CD surface heating is also presented. In this contribution, we also demonstrate an advanced application of pull pumping through the implementation of valve-less switch pumping.

  9. Push pull microfluidics on a multi-level 3D CD

    PubMed Central

    Thio, Tzer Hwai Gilbert; Ibrahim, Fatimah; Al-Faqheri, Wisam; Moebius, Jacob; Khalid, Noor Sakinah; Soin, Norhayati; Kahar, Maria Kahar Bador Abdul; Madou, Marc

    2013-01-01

    A technique known as thermo-pneumatic (TP) pumping is used to pump fluids on a microfluidic compact disc (CD) back towards the CD center against the centrifugal force that pushes liquids from the center to the perimeter of the disc. Trapped air expands in a TP air chamber during heating, and this creates positive pressure on liquids located in chambers connected to that chamber. While the TP air chamber and connecting channels are easy to fabricate in a one-level CD manufacturing technique, this approach provides only one way pumping between two chambers, is real-estate hungry and leads to unnecessary heating of liquids in close proximity to the TP chamber. In this paper, we present a novel TP push and pull pumping method which allows for pumping of liquid in any direction between two connected liquid chambers. To ensure that implementation of TP push and pull pumping also addresses the issue of space and heating challenges, a multi-level 3D CD design is developed, and localized forced convection heating, rather than infra-red (IR) is applied. On a multi-level 3D CD, the TP features are placed on a top level separate from the rest of the microfluidic processes that are implemented on a lower separate level. This approach allows for heat shielding of the microfluidic process levels, and efficient usage of space on the CD for centrifugal handling of liquids. The use of localized forced convection heating, rather than infra-red (IR) or laser heating in earlier implementations allows not only for TP pumping of liquids while the CD is spinning but also makes heat insulation for TP pumping and other fluidic functions easier. To aid in future implementations of TP push and pull pumping on a multi-level 3D CD, study on CD surface heating is also presented. In this contribution, we also demonstrate an advanced application of pull pumping through the implementation of valve-less switch pumping. PMID:23774994

  10. Push-Pull and Feedback Mechanisms Can Align Signaling System Outputs with Inputs.

    PubMed

    Andrews, Steven S; Peria, William J; Yu, Richard C; Colman-Lerner, Alejandro; Brent, Roger

    2016-11-23

    Many cell signaling systems, including the yeast pheromone response system, exhibit "dose-response alignment" (DoRA), in which output of one or more downstream steps closely matches the fraction of occupied receptors. DoRA can improve the fidelity of transmitted dose information. Here, we searched systematically for biochemical network topologies that produced DoRA. Most networks, including many containing feedback and feedforward loops, could not produce DoRA. However, networks including "push-pull" mechanisms, in which the active form of a signaling species stimulates downstream activity and the nominally inactive form reduces downstream activity, enabled perfect DoRA. Networks containing feedbacks enabled DoRA, but only if they also compared feedback to input and adjusted output to match. Our results establish push-pull as a non-feedback mechanism to align output with variable input and maximize information transfer in signaling systems. They also suggest genetic approaches to determine whether particular signaling systems use feedback or push-pull control. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. 27. INTERIOR OF KITCHEN SHOWING ORIGINAL CABINETS, LATCHES AND PULLS, ...

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

    27. INTERIOR OF KITCHEN SHOWING ORIGINAL CABINETS, LATCHES AND PULLS, AND WOOD-FRAME SLIDING-GLASS WINDOWS ABOVE SINK. VIEW TO EAST. - Rush Creek Hydroelectric System, Clubhouse Cottage, Rush Creek, June Lake, Mono County, CA

  12. A high-sensitivity push-pull magnetometer

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

    Breschi, E.; Grujić, Z. D.; Knowles, P.

    2014-01-13

    We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/√(Hz), using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/√(Hz)

  13. The construction phase’s influence to the moving ability of cross-sections of woven structure

    NASA Astrophysics Data System (ADS)

    Inogamdjanov, D.; Daminov, A.; Kasimov, O.

    2017-10-01

    The purpose of this study is to work out bases to predict properties for single layer flat woven fabrics depending on changes of construction phases. A structural model of cross-section of single layered fabric is described based on the Pierce’s model. Form transformation of the yarn like straight, semi-arch and arch yarn is considered according to the alteration of yarn tension under the theory of Novikov. The value contributions to movement index of warp and weft yarn and their total moving ability in cross-sections at all structure phases of fabric are summarized.

  14. Biomechanically determined hand force limits protecting the low back during occupational pushing and pulling tasks.

    PubMed

    Weston, Eric B; Aurand, Alexander; Dufour, Jonathan S; Knapik, Gregory G; Marras, William S

    2018-06-01

    Though biomechanically determined guidelines exist for lifting, existing recommendations for pushing and pulling were developed using a psychophysical approach. The current study aimed to establish objective hand force limits based on the results of a biomechanical assessment of the forces on the lumbar spine during occupational pushing and pulling activities. Sixty-two subjects performed pushing and pulling tasks in a laboratory setting. An electromyography-assisted biomechanical model estimated spinal loads, while hand force and turning torque were measured via hand transducers. Mixed modelling techniques correlated spinal load with hand force or torque throughout a wide range of exposures in order to develop biomechanically determined hand force and torque limits. Exertion type, exertion direction, handle height and their interactions significantly influenced dependent measures of spinal load, hand force and turning torque. The biomechanically determined guidelines presented herein are up to 30% lower than comparable psychophysically derived limits and particularly more protective for straight pushing. Practitioner Summary: This study utilises a biomechanical model to develop objective biomechanically determined push/pull risk limits assessed via hand forces and turning torque. These limits can be up to 30% lower than existing psychophysically determined pushing and pulling recommendations. Practitioners should consider implementing these guidelines in both risk assessment and workplace design moving forward.

  15. Selectively Encrypted Pull-Up Based Watermarking of Biometric data

    NASA Astrophysics Data System (ADS)

    Shinde, S. A.; Patel, Kushal S.

    2012-10-01

    Biometric authentication systems are becoming increasingly popular due to their potential usage in information security. However, digital biometric data (e.g. thumb impression) are themselves vulnerable to security attacks. There are various methods are available to secure biometric data. In biometric watermarking the data are embedded in an image container and are only retrieved if the secrete key is available. This container image is encrypted to have more security against the attack. As wireless devices are equipped with battery as their power supply, they have limited computational capabilities; therefore to reduce energy consumption we use the method of selective encryption of container image. The bit pull-up-based biometric watermarking scheme is based on amplitude modulation and bit priority which reduces the retrieval error rate to great extent. By using selective Encryption mechanism we expect more efficiency in time at the time of encryption as well as decryption. Significant reduction in error rate is expected to be achieved by the bit pull-up method.

  16. The Effects of Check-In/Check-Out on Problem Behavior and Academic Engagement in Elementary School Students

    ERIC Educational Resources Information Center

    Miller, Leila M.; Dufrene, Brad A.; Sterling, Heather E.; Olmi, D. Joe; Bachmayer, Erica

    2015-01-01

    This study evaluated the effectiveness of Check-in/Check-out (CICO) for improving behavioral performance for three students referred for Tier 2 behavioral supports. An ABAB withdrawal design was used to evaluate CICO and results indicate that intervention was effective for reducing problem behavior as well as increasing academic engagement for all…

  17. Initiation, evolution and extinction of pull-apart basins: Implications for opening of the Gulf of California

    NASA Astrophysics Data System (ADS)

    van Wijk, J.; Axen, G.; Abera, R.

    2017-11-01

    We present a model for the origin, crustal architecture, and evolution of pull-apart basins. The model is based on results of three-dimensional upper crustal elastic models of deformation, field observations, and fault theory, and is generally applicable to basin-scale features, but predicts some intra-basin structural features. Geometric differences between pull-apart basins are inherited from the initial geometry of the strike-slip fault step-over, which results from the forming phase of the strike-slip fault system. As strike-slip motion accumulates, pull-apart basins are stationary with respect to underlying basement, and the fault tips propagate beyond the rift basin, increasing the distance between the fault tips and pull-apart basin center. Because uplift is concentrated near the fault tips, the sediment source areas may rejuvenate and migrate over time. Rift flank uplift results from compression along the flank of the basin. With increasing strike-slip movement the basins deepen and lengthen. Field studies predict that pull-apart basins become extinct when an active basin-crossing fault forms; this is the most likely fate of pull-apart basins, because basin-bounding strike-slip systems tend to straighten and connect as they evolve. The models show that larger length-to-width ratios with overlapping faults are least likely to form basin-crossing faults, and pull-apart basins with this geometry are thus most likely to progress to continental rupture. In the Gulf of California, larger length-to-width ratios are found in the southern Gulf, which is the region where continental breakup occurred rapidly. The initial geometry in the northern Gulf of California and Salton Trough at 6 Ma may have been one of widely-spaced master strike-slip faults (lower length-to-width ratios), which our models suggest inhibits continental breakup and favors straightening of the strike-slip system by formation of basin-crossing faults within the step-over, as began 1.2 Ma when the

  18. Toward automating Hammersmith pulled-to-sit examination of infants using feature point based video object tracking.

    PubMed

    Dogra, Debi P; Majumdar, Arun K; Sural, Shamik; Mukherjee, Jayanta; Mukherjee, Suchandra; Singh, Arun

    2012-01-01

    Hammersmith Infant Neurological Examination (HINE) is a set of tests used for grading neurological development of infants on a scale of 0 to 3. These tests help in assessing neurophysiological development of babies, especially preterm infants who are born before (the fetus reaches) the gestational age of 36 weeks. Such tests are often conducted in the follow-up clinics of hospitals for grading infants with suspected disabilities. Assessment based on HINE depends on the expertise of the physicians involved in conducting the examinations. It has been noted that some of these tests, especially pulled-to-sit and lateral tilting, are difficult to assess solely based on visual observation. For example, during the pulled-to-sit examination, the examiner needs to observe the relative movement of the head with respect to torso while pulling the infant by holding wrists. The examiner may find it difficult to follow the head movement from the coronal view. Video object tracking based automatic or semi-automatic analysis can be helpful in this case. In this paper, we present a video based method to automate the analysis of pulled-to-sit examination. In this context, a dynamic programming and node pruning based efficient video object tracking algorithm has been proposed. Pulled-to-sit event detection is handled by the proposed tracking algorithm that uses a 2-D geometric model of the scene. The algorithm has been tested with normal as well as marker based videos of the examination recorded at the neuro-development clinic of the SSKM Hospital, Kolkata, India. It is found that the proposed algorithm is capable of estimating the pulled-to-sit score with sensitivity (80%-92%) and specificity (89%-96%).

  19. Sexual behavior and the influencing factors among out of school female adolescents in Mushin market, Lagos, Nigeria.

    PubMed

    Odeyemi, Kofoworola; Onajole, Adebayo; Ogunowo, Babatunde

    2009-01-01

    High rates of adolescent pregnancy, sexually transmitted infections, and unsafe abortions in Nigeria indicate the need for a greater understanding of factors that affect adolescent sexuality. The sexual health needs of adolescents remain poorly known and addressed particularly among vulnerable subpopulations like out-of-school adolescents. The objective of this study was to examine the sexual behavior of female out-of-school adolescents and to identify factors that influence their sexual behavior. This cross-sectional study was conducted among a representative sample of unmarried, out-of-school female adolescents (n = 332, mean age 17 y), selected using cluster sampling, who were working in a major market (Mushin) in Lagos, Nigeria. Data were collected using interviewer administered questionnaires. Many girls (43.7%) have had sexual intercourse. The mean age at initiation was 16 years. The main reason for initiation was curiosity. Risky sexual behavior and transactional sex was common. Nonconsensual sex was also reported. Sexual health knowledge was poor, and friends served as their main source of information on sexual health issues. Factors associated with the initiation of sexual activity were friends sexual behavior, the person adolescents reside with, parents marital status, availability of funds to meet basic needs, and watching pornography (p < .05). Out-of-school female adolescents engaging in risky sexual behavior are exposed to sexual abuse, lack skills to resist pressure, and have limited access to credible reproductive health information. Appropriate interventions including provision of sexuality education and a supportive environment must be instituted to address their needs.

  20. No-Drain Single Incision Liposuction Pull-Through Technique for Gynecomastia.

    PubMed

    Khalil, Ashraf A; Ibrahim, Amr; Afifi, Ahmed M

    2017-04-01

    Several different methods have been proposed for treatment of gynecomastia, depending on the amount of breast enlargement and skin redundancy. The liposuction pull-through technique has been proposed as an efficacious treatment for many gynecomastia cases. This work aims to study the outcome of this technique when applied as an outpatient procedure, without the use of drains and through a single incision. Fifty-two patients with bilateral gynecomastia without significant skin excess were included in this study. The liposuction pull-through technique was performed through a single incision just above the inframammary fold and without the use of drains. Patients were followed up for 6 months. The proposed technique was able to treat the gynecomastia in all patients, with a revision rate of 1.9% to remove residual glandular tissues. There were no seromas, hematomas, nipple distortion, permanent affection of nipple sensation or wound healing problems. The liposuction pull-through technique is an effective treatment for gynecomastia without significant skin redundancy. It combines the benefits of the direct excision of glandular tissues, with the minimally invasive nature of liposuction. Performing the procedure through a single incision without the use of drains and without general anesthesia is a safe alternative. 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 http://www.springer.com/00266 .

  1. The anomaly in a breakthrough curve of a single well "push-pull" tracer test: A density driven effect?

    NASA Astrophysics Data System (ADS)

    Zeilfelder, Sarah; Hebig, Klaus; Ito, Narimitsu; Machida, Isao; Scheytt, Traugott; Marui, Atsunao

    2013-04-01

    What method is appropriate to investigate an aquifer when there is only one well available? A single well "push-pull" tracer test (PP Test) may be a suitable method in order to characterize an aquifer and to obtain information about the hydraulic and chemical properties when only one well is available for the investigations. In a PP test, a test solution that contains a known amount of solutes and a conservative tracer is injected into the aquifer ("push") and extracted afterwards ("pull"). Optionally, the test solution is flushed out of the well and the casing with untreated test solution with a so called "chaser" before being extracted. Also between the injection and the extraction phase a drifting time may be included. The breakthrough of the tracer during the extraction phase is measured and used for analyses and interpretation. In the last three years, several PP Test campaigns were conducted at two different test sites in Japan (Hebig et al. 2011, Zeilfelder et al. 2012). The aim was to investigate the applicability of the PP Test method in different geological settings and in different types of aquifers. The latest field campaign thus focussed on the question how variations of the setup are influencing the breakthrough curve of the PP Test in order to develop and enhance this method. Also the standardization of the PP Test was an aim of this study. During the campaign, a total of seven PP Tests were performed, while only single aspects of the setup were varied from test to test. The tests differed in injection and extraction rate, in the salinity of the injected test solution and in the use of a chaser solution. The general shapes of the breakthrough curves were similar and conclusions about the repeatability of the PP Test could be drawn. However, a sharp anomaly was observed in the breakthrough curve of one specific setup type. By repeating this PP test under the same boundary conditions, we were able to recreate the anomaly and could exclude any technical

  2. Rooting Out Aberrant Behavior in Training.

    ERIC Educational Resources Information Center

    Kokalis, Jerry, Jr.; Paquin, Dave

    1989-01-01

    Discusses aberrant, or disruptive, behavior in an industrial/business, classroom-based, instructor-led training setting. Three examples of aberrant behavior are described, typical case studies are provided for each, and preventive (long-term) and corrective (on-the-spot) strategies for dealing with the problems are discussed. (LRW)

  3. Speed of pulled fronts with a cutoff

    NASA Astrophysics Data System (ADS)

    Benguria, R. D.; Depassier, M. C.

    2007-05-01

    We study the effect of a small cutoff γ on the velocity of a pulled front in one dimension by means of a variational principle. We obtain a lower bound on the speed dependent on the cutoff, for which the two leading order terms correspond to the Brunet-Derrida expression. To do so we cast a known variational principle for the speed of propagation of fronts in different variables which makes it more suitable for applications.

  4. Urethral pull-through operation for the management of pelvic fracture urethral distraction defects.

    PubMed

    Yin, Lei; Li, Zhenhua; Kong, Chuize; Yu, Xiuyue; Zhu, Yuyan; Zhang, Yuxi; Jiang, Yuanjun

    2011-10-01

    To present our institutional experience in the management of pelvic fracture urethral distraction defects with urethral pull-through operation. Seventy-six patients (average age 34.5 years) with posterior urethral strictures caused by pelvic fracture urethral distraction defects underwent urethral pull-through operation at our department from July 1995 to September 2009. The estimated urethral stricture length was 2.0-3.5 cm (mean 2.5). Of these patients, 31 (41%) had undergone failed urethroplasty or urethrotomy after the initial management, and 5 (7%) had urethrorectal fistula. Urethral pull-through operation was performed 4-7 months (mean 4.9) after initial treatment or failed urethral reconstruction. The clinical outcome was considered a failure when any postoperative intervention was needed. Follow-up was 14-74 months (mean 42.5). The overall success rate was 89% (68/76). All treatment failures occurred within the first 6 months postoperatively. Failed repairs were successfully managed with internal urethrotomy in 1 patient, by urethral dilation in 6, and by another urethroplasty in 1. All patients were urinary-continent postoperatively. Of the potent patients, 2 (5%) became impotent after urethroplasty. There was no chordee, penile shortening, or urethral fistula recurrence. Urethral pull-through operation might be a less demanding and less time-consuming procedure. It does not increase the rate of impotence or incontinence and, with a high success rate, might serve as an alternative method for the management of pelvic fracture urethral distraction defects. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. Brief Cognitive Behavioral Family Therapy Following a Child's Coming Out: A Case Report

    ERIC Educational Resources Information Center

    Willoughby, Brian L. B.; Doty, Nathan D.

    2010-01-01

    Few interventions have been proposed for the treatment of families following a child's disclosure of nonheterosexuality. To address this gap in the literature, the current paper outlines a brief cognitive behavioral family treatment (CBFT) for families negotiating the coming-out process and illustrates this approach with a case example. Parents'…

  6. Time out

    MedlinePlus

    ... but no more than 5 minutes. Once your child shows bad behavior, explain clearly what the unacceptable behavior is, and ... a grudge -- let the issue go. Since your child has done the time out, there is no need to continue to discuss the bad behavior.

  7. Using Video to Bridge the Gap Between Problem Behavior and a Delayed Time-out Procedure.

    PubMed

    Coppage, Sara; Meindl, James N

    2017-09-01

    Treatment plans focused on problem behavior often include punishment contingencies to decrease problem behavior. Immediate punishers are typically more effective than delayed punishers, but immediate delivery of a punisher is not always possible. Strategies need to be developed to increase the suppressive effects of delayed punishers. This study demonstrated the effectiveness of a treatment package involving replaying a video recording of problem behavior immediately before delivering a 15 min delayed time-out. This treatment package may prove to be an accessible and inexpensive strategy when using delayed punishers.

  8. Pulling a Door Open by Pushing on It

    ERIC Educational Resources Information Center

    van den Berg, Willem H.

    2007-01-01

    Ordinarily, opening a door by pulling on the knob or handle causes a net torque on the door, and hence an angular acceleration, about a "vertical" axis. However, it may be that the top or bottom of the door sticks to the door frame; this horizontal force perpendicular to the plane of the door causes a torque on the door about a "horizontal" axis.…

  9. Kinematics and kinetics of the bench-press and bench-pull exercises in a strength-trained sporting population.

    PubMed

    Pearson, Simon N; Cronin, John B; Hume, Patria A; Slyfield, David

    2009-09-01

    Understanding how loading affects power production in resistance training is a key step in identifying the most optimal way of training muscular power - an essential trait in most sporting movements. Twelve elite male sailors with extensive strength-training experience participated in a comparison of kinematics and kinetics from the upper body musculature, with upper body push (bench press) and pull (bench pull) movements performed across loads of 10-100% of one repetition maximum (1RM). 1RM strength and force were shown to be greater in the bench press, while velocity and power outputs were greater for the bench pull across the range of loads. While power output was at a similar level for the two movements at a low load (10% 1RM), significantly greater power outputs were observed for the bench pull in comparison to the bench press with increased load. Power output (Pmax) was maximized at higher relative loads for both mean and peak power in the bench pull (78.6 +/- 5.7% and 70.4 +/- 5.4% of 1RM) compared to the bench press (53.3 +/- 1.7% and 49.7 +/- 4.4% of 1RM). Findings can most likely be attributed to differences in muscle architecture, which may have training implications for these muscles.

  10. Fiber glass pulling. [in space

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.

    1987-01-01

    Experiments were conducted to determine the viability of performing containerless glass fiber pulling in space. The optical transmission properties and glass-forming capabilities of the heavy metal fluorides are reviewed and the acoustic characteristics required for a molten glass levitation system are examined. The design limitations of, and necessary modifications to the acoustic levitation furnace used in the experiments are discussed in detail. Acoustic levitator force measurements were performed and a thermal map of the furnace was generated from thermocouple data. It was determined that the thermal capability of the furnace was inadequate to melt a glass sample in the center. The substitution of a 10 KW carbon monoxide laser for the original furnace heating elements resulted in improved melt heating.

  11. Pulled microcapillary tube resonators with electrical readout for mass sensing applications

    PubMed Central

    Lee, Donghyuk; Kim, Joonhui; Cho, Nam-Joon; Kang, Taewook; Kauh, Sangken; Lee, Jungchul

    2016-01-01

    This paper reports a microfabrication-free approach to make hollow channel mass sensors by pulling a glass capillary and suspending it on top of a machined jig. A part of the pulled section makes simple contact with an actuation node and a quartz tuning fork (QTF) which acts as a sensing node. The two nodes define a pulled micro capillary tube resonator (PμTR) simply supported at two contacts. While a piezo actuator beneath the actuation node excites the PμTR, the QTF senses the resonance frequency of the PμTR. The proposed concept was validated by electrical and optical measurements of resonant spectra of PμTR. Then, different liquid samples including water, ethanol, glycerol, and their binary mixtures were introduced into the PμTR and the resonance frequency of the PμTR was measured as a function of liquid density. Density responsivity of −3,088 Hz-g−1 cm3 obtained is comparable to those of microfabricated hollow resonators. With a micro droplet generation chip configured in series with the PμTR, size distribution of oil droplets suspended in water was successfully measured with the radius resolution of 31 nm at the average droplet radius, 28.47 μm. Overall, typical off-the-shelf parts simply constitute a resonant mass sensing system along with a convenient electrical readout. PMID:27694852

  12. Associations Between Sedentary Behavior, Physical Activity, and Out-of-Pocket Health Care Expenditure: Evidence From Chinese Older Adults.

    PubMed

    Yu, Hongjun; Schwingel, Andiara

    2018-06-12

    This study examined the associations between sedentary behavior, physical activity, and health care expenditures among Chinese older adults. We conducted a survey on 4,165 older men and women living in major cities in China. Sedentary behavior and physical activity were measured by the Physical Activity Scale for the Elderly (PASE) questionnaire. Healthcare costs were assessed by self-reported out-of-pocket health care expenditures across outpatient care, inpatient care, medication, and formal caregiver expenses. Sedentary behavior was associated with an increase in annual out-of-pocket health care expenditures by approximately USD$37 for each additional sedentary hour (p < 0.001). Physical activity was associated with a decrease in annual health care expenditures by approximately USD$1.2 for each 1 PASE score (p < 0.001). Physical activity was a less salient indicator of health care expenditure for men than women. Reducing sedentary behavior among older men and women and promoting physical activity, especially among men, may be important strategies to reduce out-of-pocket health care expenditures in China.

  13. Benefit of "Push-pull" Locomotion for Planetary Rover Mobility

    NASA Technical Reports Server (NTRS)

    Creager, Colin M.; Moreland, Scott Jared; Skonieczny, K.; Johnson, K.; Asnani, V.; Gilligan, R.

    2011-01-01

    As NASAs exploration missions on planetary terrains become more aggressive, a focus on alternative modes of locomotion for rovers is necessary. In addition to climbing steep slopes, the terrain in these extreme environments is often unknown and can be extremely hard to traverse, increasing the likelihood of a vehicle or robot becoming damaged or immobilized. The conventional driving mode in which all wheels are either driven or free-rolling is very efficient on flat hard ground, but does not always provide enough traction to propel the vehicle through soft or steep terrain. This paper presents an alternative mode of travel and investigates the fundamental differences between these locomotion modes. The methods of push-pull locomotion discussed can be used with articulated wheeled vehicles and are identified as walking or inchinginch-worming. In both cases, the braked non-rolling wheels provide increased thrust. An in-depth study of how soil reacts under a rolling wheel vs. a braked wheel was performed by visually observing the motion of particles beneath the surface. This novel technique consists of driving or dragging a wheel in a soil bin against a transparent wall while high resolution, high-rate photographs are taken. Optical flow software was then used to determine shearing patterns in the soil. Different failure modes were observed for the rolling and braked wheel cases. A quantitative comparison of inching vs. conventional driving was also performed on a full-scale vehicle through a series of drawbar pull tests in the Lunar terrain strength simulant, GRC-1. The effect of tire stiffness was also compared; typically compliant tires provide better traction when driving in soft soil, however its been observed that rigid wheels may provide better thrust when non-rolling. Initial tests indicate up to a possible 40 increase in pull force capability at high slip when inching vs. rolling.

  14. Simplified Habit Reversal Treatment for Chronic Hair Pulling in Three Adolescents: A Clinical Replication with Direct Observation.

    ERIC Educational Resources Information Center

    Rapp, John T.; Miltenberger, Raymond G.; Long, Ethan S.; Elliott, Amy J.; Lumley, Vicki A.

    1998-01-01

    Three developmentally normal adolescents with chronic hair pulling were treated with a simplified habit-reversal procedure consisting of awareness training, competing response training, and parental social support. Treatment resulted in immediate reduction to near-zero levels of hair pulling with one to three booster sessions. Results were…

  15. Electromyographic analysis of three different types of lat pull-down.

    PubMed

    Sperandei, Sandro; Barros, Marcos A P; Silveira-Júnior, Paulo C S; Oliveira, Carlos G

    2009-10-01

    The purpose of this work was to evaluate the activity of the primary motor muscles during the performance of 3 lat pull-down techniques through surface electromyography (EMG). Twenty-four trained adult men performed 5 repetitions of behind-the-neck (BNL), front-of-the-neck (FNL), and V-bar exercises at 80% of 1 repetition maximum. For each technique, the root mean square from the EMG signal was registered from the pectoralis major (PM), latissimus dorsi (LD), posterior deltoid (PD), and biceps brachii (BB) and further normalized in respect to that which presented the highest value of all the techniques. A series of two-way repeated measures analysis of variance was used to compare the results, with Tukey-Kramer as the post hoc test and alpha = 0.05. During the concentric phase, PM value showed the FNL to be significantly higher than V-bar/BNL and V-bar higher than BNL. During the eccentric phase, FNL/V-bar was higher than BNL. For LD, there was no difference between techniques. PD presented BNL higher than FNL/V-bar and FNL higher than V-bar in the concentric phase and BNL higher than V-bar in the eccentric phase. BB exhibited BNL higher than V-bar/FNL and V-bar higher than FNL in both concentric and eccentric phases. Considering the main objectives of lat pull-down, we concluded that FNL is the better choice, whereas BNL is not a good lat pull-down technique and should be avoided. V-bar could be used as an alternative.

  16. Test equipment data package for the KC-135 fiber pulling apparatus

    NASA Technical Reports Server (NTRS)

    Kosten, Sue; Smith, Guy A.; Workman, Gary; Tucker, Dennis

    1991-01-01

    The Fiber Pulling Apparatus (FPA) is a device designed to produce continuous glass fibers from simulated lunar soil, and to determine the effects of reduced gravity, specifically 1/6 g on fiber formation and resultant properties. Briefly, pre-melt simulated lunar soil will be placed in a pint crucible and heated to 1200 C or higher, up to a maximum temperature of 1400 C. At a given temperature, a quartz fiber will be immersed into the melt and then pulled through a chill block and wound onto a cylindrical bobbin using a servo motor control. A high resolution video camera will record the fiber as it is being pulled. This assembly wil be enclosed in Plexiglas. Before fiber pulling commences, the apparatus will be backfilled with dry nitrogen. A separate data acquisition system will support this apparatus. This system will contain a personal computer, video recorder, and monitor. Temperature, acceleration, winding speed, and video images will be controlled and recorded using the data acquisition system. Thus, the FPA will consist of two hardware packages, the fiber production assembly and the data acquisition rack. The primary objective of this test is to determine the effects of 1/6 g on the formation of continuous glass fiber made from simulated lunar soil. Baseline studies using the FPA on the ground will provide a reference for the 1/6 g studies. Of particular interest will be the effect of 1/6 g on the free fluid zone where the fiber exits the crucible. In the fiber spinning parlance this zone is known as the upper jet region, where the boundary slope is greater than one tenth. The properties of the resulting glass fiber will depend on the jet shape as well as distributions of velocity, temperature and tension within the jet. It is unknown at this time how 1/6 g will effect these parameters.

  17. Power-assisted liposuction and the pull-through technique for the treatment of gynecomastia.

    PubMed

    Lista, Frank; Ahmad, Jamil

    2008-03-01

    Gynecomastia is a common condition affecting many adolescent and adult males. Surgical techniques utilizing a variety of incisions, excisions, suction-assisted lipectomy, ultrasound-assisted liposuction, power-assisted liposuction, or some combination of these methods have been used in the treatment of gynecomastia. This article describes the authors' method of using power-assisted liposuction and the pull-through technique to treat gynecomastia. This technique involves the use of power-assisted liposuction to remove fatty breast tissue. The pull-through technique is then performed utilizing several instruments to sever the subdermal attachments of fibroglandular breast tissue; this tissue is removed through the incision used for liposuction. Finally, power-assisted liposuction is performed again to contour the remaining breast tissue. A chart review of 99 consecutive patients (197 breasts) treated between January of 2003 and November of 2006 was performed. Ninety-six patients (192 breasts) were successfully treated using this technique. Power-assisted liposuction was performed in all cases, and the average volume aspirated per breast was 459 ml (range, 25 to 1400 ml). Using the pull-through technique, the authors were able to remove between 5 and 70 g of tissue per breast. Complications were minimal (1.0 percent of breasts), and no revisions were required. Since January of 2003, the authors have used this technique to successfully treat 97 percent of their gynecomastia patients. Combining power-assisted liposuction and the pull-through technique has proven to be a versatile approach for the treatment of gynecomastia and consistently produces a naturally contoured male breast while resulting in a single inconspicuous scar.

  18. Comparison of Olympic and Hexagonal Barbells With Midthigh Pull, Deadlift, and Countermovement Jump.

    PubMed

    Malyszek, Kylie K; Harmon, RoQue A; Dunnick, Dustin D; Costa, Pablo B; Coburn, Jared W; Brown, Lee E

    2017-01-01

    Malyszek, KK, Harmon, RA, Dunnick, DD, Costa, PB, Coburn, JW, and Brown, LE. Comparison of olympic and hexagonal barbells with midthigh pull, deadlift, and countermovement jump. J Strength Cond Res 31(1): 140-145, 2017-Those training for strength and power commonly use different bars and different lifts. The hexagonal barbell (HBar) and Olympic barbell (OBar) are frequently used training implements, and the midthigh pull (MTP) and deadlift (DL) are 2 popular exercises. Therefore, the purpose of this study was to compare force between an HBar and OBar for a MTP, DL, and countermovement jump (CMJ). Twenty resistance-trained men (age = 24.05 ± 2.09 years, ht = 178.07 ± 7.05 cm, mass = 91.42 ± 14.44 kg) volunteered to participate and performed MTP and DL using both bars and a CMJ. Joint angles were recorded for all pulls and the bottom position of the CMJ. Peak ground reaction force (PGRF) was greater in the MTP (3,186.88 ± 543.53 N) than DL (2,501.15 ± 404.04 N) but not different between bars. Midthigh pull joint angles were more extended than DL, and the strongest correlations between isometric and dynamic performance were seen between DL PGRF and CMJ impulse (OBar r = 0.85; HBar r = 0.84). These findings are likely because of the different anatomical characteristics between the MTP and DL and the similarity in joint angles between the DL and CMJ. Therefore, the DL may be an optimal choice for athletes in jump-dependent sports, regardless of bar.

  19. Cooperativity of self-organized Brownian motors pulling on soft cargoes.

    PubMed

    Orlandi, Javier G; Blanch-Mercader, Carles; Brugués, Jan; Casademunt, Jaume

    2010-12-01

    We study the cooperative dynamics of Brownian motors moving along a one-dimensional track when an external load is applied to the leading motor, mimicking molecular motors pulling on membrane-bound cargoes in intracellular traffic. Due to the asymmetric loading, self-organized motor clusters form spontaneously. We model the motors with a two-state noise-driven ratchet formulation and study analytically and numerically the collective velocity-force and efficiency-force curves resulting from mutual interactions, mostly hard-core repulsion and weak (nonbinding) attraction. We analyze different parameter regimes including the limits of weak noise, mean-field behavior, rigid coupling, and large numbers of motors, for the different interactions. We present a general framework to classify and quantify cooperativity. We show that asymmetric loading leads generically to enhanced cooperativity beyond the simple superposition of the effects of individual motors. For weakly attracting interactions, the cooperativity is mostly enhanced, including highly coordinated motion of motors and complex nonmonotonic velocity-force curves, leading to self-regulated clusters. The dynamical scenario is enriched by resonances associated to commensurability of different length scales. Large clusters exhibit synchronized dynamics and bidirectional motion. Biological implications are discussed.

  20. Cooperativity of self-organized Brownian motors pulling on soft cargoes

    NASA Astrophysics Data System (ADS)

    Orlandi, Javier G.; Blanch-Mercader, Carles; Brugués, Jan; Casademunt, Jaume

    2010-12-01

    We study the cooperative dynamics of Brownian motors moving along a one-dimensional track when an external load is applied to the leading motor, mimicking molecular motors pulling on membrane-bound cargoes in intracellular traffic. Due to the asymmetric loading, self-organized motor clusters form spontaneously. We model the motors with a two-state noise-driven ratchet formulation and study analytically and numerically the collective velocity-force and efficiency-force curves resulting from mutual interactions, mostly hard-core repulsion and weak (nonbinding) attraction. We analyze different parameter regimes including the limits of weak noise, mean-field behavior, rigid coupling, and large numbers of motors, for the different interactions. We present a general framework to classify and quantify cooperativity. We show that asymmetric loading leads generically to enhanced cooperativity beyond the simple superposition of the effects of individual motors. For weakly attracting interactions, the cooperativity is mostly enhanced, including highly coordinated motion of motors and complex nonmonotonic velocity-force curves, leading to self-regulated clusters. The dynamical scenario is enriched by resonances associated to commensurability of different length scales. Large clusters exhibit synchronized dynamics and bidirectional motion. Biological implications are discussed.

  1. A Push-pull Protocol to Reduce Colonization of Bird Nest Boxes by Honey Bees.

    PubMed

    Efstathion, Caroline A; Kern, William H

    2016-09-04

    Introduction of the invasive Africanized honey bee (AHB) into the Neotropics is a serious problem for many cavity nesting birds, specifically parrots. These bees select cavities that are suitable nest sites for birds, resulting in competition. The difficulty of removing bees and their defensive behavior makes a prevention protocol necessary. Here, we describe a push-pull integrated pest management protocol to deter bees from inhabiting bird boxes by applying a bird safe insecticide, permethrin, to repel bees from nest boxes, while simultaneously attracting them to pheromone-baited swarm traps. Shown here is an example experiment using Barn Owl nest boxes. This protocol successfully reduced colonization of Barn Owl nest boxes by Africanized honey bees. This protocol is flexible, allowing adjustments to accommodate a wide range of bird species and habitats. This protocol could benefit conservation efforts where AHB are located.

  2. Motivation and Perception of Tourists as Push and Pull Factors to Visit National Park

    NASA Astrophysics Data System (ADS)

    Said, Jumrin; Maryono

    2018-02-01

    Push-pull theoretical framework is a popular theory to explain the reason why the tourists decide to visit the destination rather than other place, the kind of experience they want to get and the type of activity they want to do. In this paper, it is explained the motivation as push factors and the perception as pull factors of the tourist in deciding the destination based on previous literature and research using descriptive method. The framework asumed that tourists are motivated to fulfill their needs, including to reduce the psychological imbalance and to gain recognition of social status. National Park is one of destination based on nature or commonly knowns as ecotourism. In choosing the destination, the tourists tend to classify their alternative choice based on several criteria, such as the domination perception of tourist from one destination (pull factor), self motivation (push factor) and the available time and money (situational constraints).

  3. Plasma Push and Pull

    NASA Image and Video Library

    2015-07-08

    Dark strands of plasma hovering above the sun's surface began to interact with each other in a form of tug of war over two and a half days on June 28-30, 2015. At times, strands of plasma extended a tenuous connection between one area and the other. Twice the small tower of plasma to the lower left shot a burst of energy over to the quivering filament higher up. We are seeing the push and pull of magnetic forces revealed in a 193 wavelength of extreme ultraviolet light, typically colorized in brown. Credit: NASA/SDO NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  4. Determinants and magnitudes of manual force strengths and joint moments during two-handed standing maximal horizontal pushing and pulling.

    PubMed

    Chow, Amy Y; Dickerson, Clark R

    2016-04-01

    Pushing and pulling are common occupational exertions that are increasingly associated with musculoskeletal complaints. This study focuses on the sensitivity of shoulder capacity to gender, handle height, exertion type (push or pull) and handle orientation for these tasks. All factors except for handle orientation influenced unilateral and total manual force strength (p < 0.01), with exertion type being the most influential. Interaction effects also existed between handle height and exertion type. Additionally, joint moments at the shoulders and low back were influenced by all factors studied (p < 0.01), with exertion type again being most influential. Knowledge of the relative influence of multiple factors on shoulder capacity can provide guidance regarding these factors when designing or evaluating occupational pushing and pulling tasks for a diverse population. Practitioner Summary: pushing and pulling comprise nearly half of all manual materials handling tasks. Practitioners often assess, design or modify these tasks while incorporating constraints, including manual force direction and handle interface. This study provides guidance to aid design of pushing and pulling tasks in the context of shoulder physical capacity.

  5. RISKY SEXUAL BEHAVIOR AMONG OUT-OF-SCHOOL THAI AND NON-THAI YOUTH IN URBAN CHIANG MAI, THAILAND.

    PubMed

    Musumari, Patou Masika; Tangmunkongvorakul, Arunrat; Srithanaviboonchai, Kriengkrai; Manoyosa, Veruree; Tarnkehard, Surapee; Techasrivichien, Teeranee; Suguimoto, S Pilar; Ono-Kihara, Masako; Kihara, Masahiro; Chariyalertsak, Suwat

    2017-01-01

    Out-of-school youth in Thailand engage in risky sexual behavior that puts them at risk for contracting HIV infection and can have other negative sexual reproductive health outcomes. No study has examined risky sexual behaviors and compared them between Thai and non-Thai out-of-school youth. The current study compares sexual risk behavior and HIV testing behavior between out-of-school Thai and non-Thai youth. We conducted face-to-face interviews in this study population in urban Chiang Mai during 2014. Participants were recruited through convenience sampling from two main sources: non-formal education centers (NFECs) and social meeting places. We recruited 924 youth, aged 15-24 years, of whom 424 (45.9%) were Thai and 500 (54.1%) were non-Thai. The majority were attending NFECs (82.3%). Of the sexually experienced participants (57.7%), 75.4% did not use condoms consistently, and 50.3% had at least 2 lifetime sexual partners. Among the study participants, the Thai studied youth had significantly higher odds of ever having had sex (AOR=2.33; 95% CI: 1.56-3.49; p<0.001), having an earlier sexual debut (AOR=5.52; 95% CI: 2.71-11.25; p<0.001) and having a larger number of lifetime sexual partners (AOR=2.31; 95% CI: 1.37-3.88; p=0.002) than non-Thai participants. There was no significant difference between the Thai and non-Thai participants in terms of having HIV testing. The Thai studied youth were more likely to engage in risky sexual behavior than the non-Thai youth. However, both groups displayed risky sexual behaviors. Future research should explore indepth the drivers of risky sexual behaviors among both Thai and non-Thai youth.

  6. Pulling boat hands: a unique dermatosis from coastal New England.

    PubMed

    Toback, A C; Korson, R; Krusinski, P A

    1985-04-01

    We report a previously unrecognized hand dermatosis, pulling boat hands (PBH), occurring in thirteen participants at the Outward Bound School on Hurricane Island, Maine. Painful and pruritic macules, plaques, and vesicles developed exclusively while subjects lived aboard a pulling boat, the school's open rowing/sailing craft. Nine of those affected were women and eight had Raynaud's phenomenon or vasospasm. These subjects experienced thirty episodes of PBH during May through October, 1978 to 1982. Histopathology revealed a superficial and deep lymphohistiocytic perivascular infiltrate, subepidermal blister formation, red blood cell extravasation, and dermal capillary thrombosis compatible with cold injury to the skin. All patients experienced prolonged percussion to their hands while rowing as well as a continuous environmental exposure to cold air, wind, humidity, ocean spume, and precipitation. These clinical, histopathologic, and environmental findings suggest a unique syndrome that combines the vascular effects of mechanical trauma from rowing with those of nonfreezing cold injury.

  7. Impact of slab pull and incipient mantle delamination on active tectonics and crustal thickening in the Betic-Alboran-Rif system

    NASA Astrophysics Data System (ADS)

    Mazzotti, Stephane; Baratin, Laura-May; Chéry, Jean; Vernant, Philippe; Gueydan, Frédéric; Tahayt, Abdelilah; Mourabit, Taoufik

    2017-04-01

    In Western Mediterranean, the Betic-Alboran-Rif orocline accommodates the WNW-ESE convergence between the Nubia and Eurasia plates. Recent geodetic data show that present-day tectonics in northern Morocco and southernmost Spain are not compatible with this simple two-plate-convergence model: GPS observations indicate significant (2-4 mm/a) deviations from the expected plate motion, and gravity data define two major negative Bouguer anomalies beneath the Betic and south of the Rif, interpreted as a thickened crust in a state of non-isostatic equilibrium. These anomalous geodetic patterns are likely related to the recent impact of the sub-vertical Alboran slab on crustal tectonics. Using 2-D finite-element models, we study the first-order behavior of a lithosphere affected by a downward normal traction, representing the pull of a high-density body in the upper mantle (slab pull or mantle delamination). We show that a specific range of lower crust and upper mantle viscosities allow a strong coupling between the mantle and the base of the brittle crust, thus enabling (1) the efficient conversion of vertical movement (resulting from the downward traction) to horizontal movement and (2) shortening and thickening on the brittle upper crust. Our results show that incipient delamination of the Nubian continental lithosphere, linked to the Alboran slab pull, can explain the present-day abnormal tectonics and non-isostatic equilibrium in northern Morocco. Similar processes may be at play in the whole Betic-Alboran-Rif region, although the fast temporal evolution of the slab - upper plate interactions needs to be taken into account to better understand this complex system.

  8. Submucosal nerve diameter of greater than 40 μm is not a valid diagnostic index of transition zone pull-through.

    PubMed

    Kapur, Raj P

    2016-10-01

    Submucosal nerve hypertrophy is a feature of the transition zone in Hirschsprung disease and has been used as a primary diagnostic feature of transition zone pull-through for patients with persistent obstructive symptoms after their initial surgery. Most published criteria for identification of hypertrophy rely on a nerve diameter of greater than 40μm, based primarily on data from a relatively small number of infants with Hirschsprung disease and controls. The validity of these objective measures has not been validated in appropriate controls for post-pull-through patients. The primary pull-through specimens and post pull-through biopsies +/- redo pull-through resections from a series of 9 patients with Hirschsprung disease were reviewed to assess the prevalence of submucosal nerves >40μm in diameter and 400× microscopic fields containing two or more such nerves. Similar data from multiple colonic locations were collected from a series of 40 non-Hirschsprung autopsy and surgical controls. The overwhelming majority of Hirschsprung patients harbored submucosal nerves >40μm in their post-pull-through specimens independent of other features of transition zone pathology, and despite normal innervation at the proximal margins of their initial resections. Measurement of submucosal nerve diameters in autopsy and surgical non-Hirschsprung control samples indicated that nerves >40μm are normal in the distal rectum after 1year of age and are found in more proximal colon at older ages. These results suggest that diagnostic criteria currently used to recognize submucosal nerve hypertrophy in the neorectum after a pull-through for Hirschsprung disease are not justified and should not be regarded as definitive evidence for transition zone pull-through. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Time outs

    MedlinePlus

    ... When you yell and nag, you give your children's bad behavior too much attention. Some children may go into ... to their activities. Do not lecture about the bad behavior. Children eventually get the message with the time out.

  10. Optical pulling and pushing forces exerted on silicon nanospheres with strong coherent interaction between electric and magnetic resonances.

    PubMed

    Liu, Hongfeng; Panmai, Mingcheng; Peng, Yuanyuan; Lan, Sheng

    2017-05-29

    We investigated theoretically and numerically the optical pulling and pushing forces acting on silicon (Si) nanospheres (NSs) with strong coherent interaction between electric and magnetic resonances. We examined the optical pulling and pushing forces exerted on Si NSs by two interfering waves and revealed the underlying physical mechanism from the viewpoint of electric- and magnetic-dipole manipulation. As compared with a polystyrene (PS) NS, it was found that the optical pulling force for a Si NS with the same size is enlarged by nearly two orders of magnitude. In addition to the optical pulling force appearing at the long-wavelength side of the magnetic dipole resonance, very large optical pushing force is observed at the magnetic quadrupole resonance. The correlation between the optical pulling/pushing force and the directional scattering characterized by the ratio of the forward to backward scattering was revealed. More interestingly, it was found that the high-order electric and magnetic resonances in large Si NSs play an important role in producing optical pulling force which can be generated by not only s-polarized wave but also p-polarized one. Our finding indicates that the strong coherent interaction between the electric and magnetic resonances existing in nanoparticles with large refractive indices can be exploited to manipulate the optical force acting on them and the correlation between the optical force and the directional scattering can be used as guidance. The engineering and manipulation of optical forces will find potential applications in the trapping, transport and sorting of nanoparticles.

  11. Field Evaluation of a Push-Pull System to Reduce Malaria Transmission

    PubMed Central

    Menger, David J.; Omusula, Philemon; Holdinga, Maarten; Homan, Tobias; Carreira, Ana S.; Vandendaele, Patrice; Derycke, Jean-Luc; Mweresa, Collins K.; Mukabana, Wolfgang Richard; van Loon, Joop J. A.; Takken, Willem

    2015-01-01

    Malaria continues to place a disease burden on millions of people throughout the tropics, especially in sub-Saharan Africa. Although efforts to control mosquito populations and reduce human-vector contact, such as long-lasting insecticidal nets and indoor residual spraying, have led to significant decreases in malaria incidence, further progress is now threatened by the widespread development of physiological and behavioural insecticide-resistance as well as changes in the composition of vector populations. A mosquito-directed push-pull system based on the simultaneous use of attractive and repellent volatiles offers a complementary tool to existing vector-control methods. In this study, the combination of a trap baited with a five-compound attractant and a strip of net-fabric impregnated with micro-encapsulated repellent and placed in the eaves of houses, was tested in a malaria-endemic village in western Kenya. Using the repellent delta-undecalactone, mosquito house entry was reduced by more than 50%, while the traps caught high numbers of outdoor flying mosquitoes. Model simulations predict that, assuming area-wide coverage, the addition of such a push-pull system to existing prevention efforts will result in up to 20-fold reductions in the entomological inoculation rate. Reductions of such magnitude are also predicted when mosquitoes exhibit a high resistance against insecticides. We conclude that a push-pull system based on non-toxic volatiles provides an important addition to existing strategies for malaria prevention. PMID:25923114

  12. DINING ROOM. NOTE THE RECESSED PULLS ON THE SLIDING DOORS. ...

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

    DINING ROOM. NOTE THE RECESSED PULLS ON THE SLIDING DOORS. VIEW FACING EAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, U-Shaped Two-Bedroom Single-Family Type 6, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI

  13. Chewing and spitting out food as a compensatory behavior in patients with eating disorders.

    PubMed

    Song, Youn Joo; Lee, Jung-Hyun; Jung, Young-Chul

    2015-10-01

    Recent studies suggest that chewing and spitting out food may be associated with severe eating-related pathology. The purpose of this study was to investigate the relationship between chewing and spitting, and other symptoms of eating disorders. We hypothesized that patients who chew and spit as a compensatory behavior have more severe eating-related pathology than patients who have never engaged in chewing and spitting behavior. We divided 359 patients with eating disorders into two groups according to whether they engaged in chewing and spitting as a compensatory behavior to lose weight or not. After comparing eating-related pathology between the two groups, we examined factors associated with pathologic eating behaviors using logistic regression analysis. Among our 359 participants, 24.5% reported having engaged in chewing and spitting as a compensatory behavior. The chewing and spitting (CHSP+) group showed more severe eating disorder symptoms and suicidal behaviors. This group also had significantly higher scores on subscales that measured drive for thinness, bulimia, and impulse regulation on the EDI-2, Food Craving Questionnaire, Body Shape Questionnaire, Beck Depression Inventory, Beck Anxiety Inventory, and Maudsley Obsessive Compulsive Inventory. Chewing and spitting is a common compensatory behavior among patients with eating disorders and is associated with more-pathologic eating behaviors and higher scores on psychometric tests. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Effects of myofascial release leg pull and sagittal plane isometric contract-relax techniques on passive straight-leg raise angle.

    PubMed

    Hanten, W P; Chandler, S D

    1994-09-01

    Experimental evidence does not currently exist to support the claims of clinical effectiveness for myofascial release techniques. This presents an obvious need to document the effects of myofascial release. The purpose of this study was to compare the effects of two techniques, sagittal plane isometric contract-relax and myofascial release leg pull for increasing hip flexion range of motion (ROM) as measured by the angle of passive straight-leg raise. Seventy-five nondisabled, female subjects 18-29 years of age were randomly assigned to contract-relax, leg pull, or control groups. Pretest hip flexion ROM was measured for each subject's right hip with a passive straight-leg raise test using a fluid-filled goniometer. Subjects in the treatment groups received either contract-relax or leg pull treatment applied to the right lower extremity; subjects in the control group remained supine quietly for 5 minutes. Following treatment, posttest straight-leg raise measurements were performed. A one-way analysis of variance followed by a Newman-Keuls post hoc comparison of mean gain scores showed that subjects receiving contract-relax treatment increased their ROM significantly more than those who received leg pull treatment, and the increase in ROM of subjects in both treatment groups was significantly higher than those of the control group. The results suggest that while both contract-relax and leg pull techniques can significantly increase hip flexion ROM in normal subjects, contract-relax treatment may be more effective and efficient than leg pull treatment.

  15. Push versus pull gastrostomy in cancer patients: A single center retrospective analysis of complications and technical success rates.

    PubMed

    Currie, B M; Getrajdman, G I; Covey, A M; Alago, W; Erinjeri, J P; Maybody, M; Boas, F E

    2018-04-28

    To compare the technical success and complication rates of push versus pull gastrostomy tubes in cancer patients, and to examine their dependence on operator experience. A retrospective review was performed of 304 cancer patients (170 men, 134 women; mean age 60.3±12.6 [SD], range: 19-102 years) referred for primary gastrostomy tube placement, 88 (29%) of whom had a previously unsuccessful attempt at percutaneous endoscopic gastrostomy (PEG) placement. Analyzed variables included method of insertion (push versus pull), indication for gastrostomy, technical success, operator experience, and procedure-related complications within 30 days of placement. Gastrostomy tubes were placed for feeding in 189 patients and palliative decompression in 115 patients. Technical success was 91%: 78% after endoscopy had previously been unsuccessful and 97% when excluding failures associated with prior endoscopy. In the first 30 days, there were 29 minor complications (17.2%) associated with push gastrostomies, and only 8 minor complications (7.5%) with pull gastrostomies (P<0.05). There was no significant difference in major complications (push gastrostomy 5.3%, pull gastrostomy 5.6%). For decompressive gastrostomy tubes, the pull technique resulted in lower rates of both minor and major complications. There was no difference in complications or technical success rates for more versus less experienced operators. Pull gastrostomy tube placement had a lower rate of complications than push gastrostomy tube placement, especially when the indication was decompression. The technical success rate was high, even after a failed attempt at endoscopic placement. Both the rates of success and complications were independent of operator experience. Copyright © 2018 Société française de radiologie. Published by Elsevier Masson SAS. All rights reserved.

  16. Multiple Perspectives on Hiroshima. Pull-out 2.

    ERIC Educational Resources Information Center

    Schill, Karen

    1998-01-01

    Summarizes a unit of study in which students learn about the bombing of Hiroshima and Nagasaki through reading about the survivors of the atomic bomb explosions and reflecting on the debate surrounding the 50th anniversary commemorations in Hiroshima (Japan) and the United States. Suggests that students keep journals throughout the unit. (CMK)

  17. Telescoping low vibration pulling mechanism for Czochralski crystal growth

    NASA Astrophysics Data System (ADS)

    Iseler, G. W.

    1985-02-01

    A telescoping low vibration pulling mechanism is described for use in Czochralski crystal growth apparatus, comprising a broached brushing which defines an internal circumference of teeth on the circumference of a splined shaft. The brushing is coupled to the means for rotation via a hollow tube and the splined shaft, couplable to a seed shaft, and an elevation means telescopes through said brushing within said hollow tube.

  18. Cenozoic pull-apart basins in southwest Montana

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

    Ruppel, E.T.

    1991-06-01

    Faults and fault zones bounding the mountain ranges of southwest Montana commonly have been described as normal faults, and the region has been considered to be a northern extension of the Basin and Range. New geologic mapping suggests, however, that Cenozoic movements along most of the zones of steep faults in southwest Montana and in east-central Idaho have been strike-slip, and the intermontane basins appear to be pull-aparts. The principal fault zones trend about north, northwest, east, and north-northeast; the north-trending zones are Cenozoic in age, but the others are of Archean ancestry and are rooted in basement rocks. Thesemore » faults break the region into rhomboidal mountain blocks separated by broad basins with parallel sides. The basins are as much as 5,000 m deep, and their floors are deeply indented by centers of subsidence wherre they are crossed by major fault zones. The basins are floored by Archean or Proterozoic rocks and are filled with tuffaceous sedimentary rocks of late Oligocene to late Miocene age. The Big Hole basin and the smaller basins in upper Grasshopper Creek and Horse Prairie are interpreted to be pull-aparts between zones of east-trending right-lateral faults. The cratonic basins farther east in southwest Montana are interpreted to be basement-floored openings between mountain blocks that have been separated by subcrustal flow to the northwest. The interpretations suggest that significant accumulations of oil or gas are not likely to be found in this region.« less

  19. Three Levels of Push-Pull Dynamics among Chinese International Students' Decision to Study Abroad in the Canadian Context

    ERIC Educational Resources Information Center

    Chen, Jun Mian

    2017-01-01

    The extant literature on student migration flows generally focus on the traditional push-pull factors of migration at the individual level. Such a tendency excludes the broader levels affecting international student mobility. This paper proposes a hybrid of three levels of push-pull dynamics (micro-individual decision-making, meso-academic…

  20. Modeling the influence of the Casimir force on the pull-in instability of nanowire-fabricated nanotweezers

    NASA Astrophysics Data System (ADS)

    Farrokhabadi, Amin; Mokhtari, Javad; Rach, Randolph; Abadyan, Mohamadreza

    2015-09-01

    The Casimir force can strongly interfere with the pull-in performance of ultra-small structures. The strength of the Casimir force is significantly affected by the geometries of interacting bodies. Previous investigators have exclusively studied the effect of the Casimir force on the electromechanical instability of nanostructures with planar geometries. However no work has yet considered this effect on the pull-in instability of systems with cylindrical geometries such as nanotweezers fabricated from nanotube/nanowires. In our present work, the influence of the Casimir attraction on the electrostatic response and pull-in instability of nanotweezers fabricated from cylindrical conductive nanowires/nanotubes is theoretically investigated. An asymptotic solution, based on scattering theory, is applied to consider the effect of vacuum fluctuations in the theoretical model. The Euler-Bernoulli beam model is employed, in conjunction with the size-dependent modified couple stress continuum theory, to derive the governing equation of the nanotweezers. The governing nonlinear equations are solved by two different approaches, i.e., the modified Adomian-Padé method (MAD-Padé) and a numerical solution. Various aspects of the problem, i.e., the variation of pull-in parameters, effect of geometry, coupling between the Casimir force and size dependency effects and comparison with the van der Waals force regime are discussed.