The decrease in yield strength in NiAl due to hydrostatic pressure

Science.gov (United States)

Margevicius, R. W.; Lewandowski, J. J.; Locci, I.

1992-01-01

The decrease in yield strength in NiAl due to hydrostatic pressure is examined via a comparison of the tensile flow behavior in the low strain regime at 0.1 MPa for NiAl which was cast, extruded, and annealed for 2 hr at 827 C in argon and very slowly cooled to room temperature. Pressurization to 1.4 GPa produces a subsequent reduction at 0.1 MP in proportional limit by 40 percent as well as a 25-percent reduction in the 0.2-percent offset yield strength, while pressurization with lower pressures produces a similar reduction, although smaller in magnitude.

Using hardness to model yield and tensile strength

Energy Technology Data Exchange (ETDEWEB)

Hawk, Jeffrey A.; Dogan, Omer N.; Schrems, Karol K.

2005-02-01

The current direction in hardness research is towards smaller and smaller loads as nano-scale materials are developed. There remains, however, a need to investigate the mechanical behavior of complex alloys for severe environment service. In many instances this entails casting large ingots and making numerous tensile samples as the bounds of the operating environment are explored. It is possible to gain an understanding of the tensile strength of these alloys using room and elevated temperature hardness in conjunction with selected tensile tests. The approach outlined here has its roots in the work done by Tabor for metals and low alloy and carbon steels. This research seeks to extend the work to elevated temperatures for multi-phase, complex alloys. A review of the approach will be given after which the experimental data will be examined. In particular, the yield stress and tensile strength will be compared to their corresponding hardness based values.

Yield strength of a heavily drawn Cu-20% Nb filamentary microcomposite

International Nuclear Information System (INIS)

Hong, S.I.

1998-01-01

It has been well documented that heavily-drawn, copper-niobium microcomposites possess high strength and high conductivity. Since niobium has little solubility in copper, the conductivity of the copper is not strongly affected by the addition of niobium. Following extensive mechanical deformation of Cu-Nb, niobium dendrites transform into fine niobium ribbons as a result of the niobium texture upon drawing. This nanostructure contributes to the ultrahigh strength of Cu-Nb microcomposites. The strength of heavily deformed Cu-Nb exceeds that predicted by the rule-of-mixtures (ROM), and a fundamental understanding of the strengthening mechanisms involved has been the subject of much discussion. Spitzig and his coworkers suggests a barrier strengthening model while Funkenbusch and Courtney believe that stored dislocations have a role in substructural hardening. Hangen and Raabe recently proposed an analytical model for the calculation of the yield strength of Cu-Nb microcomposite. The model of Hangen and Raabe and that of Spitzig and his coworkers have a great deal of resemblance since both models attribute the strength to the difficulty of propagating plastic flow through the interface. The purpose of this study was to enhance the understanding of the strengthening mechanisms associated with Cu-Nb microcomposites by examining the previous studies on mechanical and microstructural stability of Cu-based microcomposites

Effects of Texture and Grain Size on the Yield Strength of ZK61 Alloy Rods Processed by Cyclic Extrusion and Compression.

Science.gov (United States)

Zhang, Lixin; Zhang, Wencong; Cao, Biao; Chen, Wenzhen; Duan, Junpeng; Cui, Guorong

2017-10-26

The ZK61 alloy rods with different grain sizes and crystallographic texture were successfully fabricated by cyclic extrusion and compression (CEC). Their room-temperature tension & compression yield strength displayed a significant dependence on grain size and texture, essentially attributed to {10-12} twinning. The texture variations were characterized by the angle θ between the c-axis of the grain and the extrusion direction (ED) during the process. The contour map of room-temperature yield strength as a function of grain size and the angle θ was obtained. It showed that both the tension yield strength and the compression yield strength of ZK61 alloy were fully consistent with the Hall-Patch relationship at a certain texture, but the change trends of the tension yield strength and the compression yield strength were completely opposite at the same grain size while texture altered. The friction stresses of different deformation modes calculated based on the texture confirmed the tension yield strength of the CECed ZK61 alloy rods, which was determined by both the basal slip and the tension twinning slip during the tension deformation at room temperature, while the compression yield strength was mainly determined by the basal slip during the compression deformation.

Development of high yield strength non-magnetic steels for the equipments of nuclear fusion research

International Nuclear Information System (INIS)

Matsuoka, Hidenori; Mukai, Tetsuya; Ohtani, Hiroo; Tsuruki, Takanori; Okada, Yasutaka

1979-01-01

Recently, activity of nuclear fusion research and so forth increase the demand of non-magnetic materials for various equipments and structures. For these usage, very low magnetic permeability as well as high strength are required under high magnetic field. Based on fundamental research, middle C-17% Cr-7% Ni-N non-magnetic steel has been developed. The developed steel shows more stable austenite phase and possesses higher yield strength and endurance limit of more than 10 kg/mm 2 , compared with 18% Cr-8% Ni austenitic steel. Also the developed steel has good ductility and toughness in spite of the high yield strength and shows better machinability than usual high Mn non- magnetic steels. The large forgings of this newly developed steel are manufactured in the works for the equipments of nuclear fusion research and confirmed good mechanical properties, high fatigue strength and low permeability. (author)

Prediction of the Dynamic Yield Strength of Metals Using Two Structural-Temporal Parameters

Science.gov (United States)

Selyutina, N. S.; Petrov, Yu. V.

2018-02-01

The behavior of the yield strength of steel and a number of aluminum alloys is investigated in a wide range of strain rates, based on the incubation time criterion of yield and the empirical models of Johnson-Cook and Cowper-Symonds. In this paper, expressions for the parameters of the empirical models are derived through the characteristics of the incubation time criterion; a satisfactory agreement of these data and experimental results is obtained. The parameters of the empirical models can depend on some strain rate. The independence of the characteristics of the incubation time criterion of yield from the loading history and their connection with the structural and temporal features of the plastic deformation process give advantage of the approach based on the concept of incubation time with respect to empirical models and an effective and convenient equation for determining the yield strength in a wider range of strain rates.

Yield strengths of flows on the earth, Mars, and moon. [application of Bingham plastic model to lava flows

Science.gov (United States)

Moore, H. J.; Arthur, D. W. G.; Schaber, G. G.

1978-01-01

Dimensions of flows on the earth, Mars, and moon and their topographic gradients obtained from remote measurements are used to calculate yield strengths with a view to explore the validity of the Bingham plastic model and determine whether there is a relation between yield strengths and silica contents. Other factors are considered such as the vagaries of natural phenomena that might contribute to erroneous interpretations and measurements. Comparison of yield strengths of Martian and lunar flows with terrestrial flows suggests that the Martian and lunar flows are more akin to terrestrial basalts than they are to terrestrial andesites, trachytes, and rhyolites.

Yield strength prediction in Ni-base alloy 718Plus based on thermo-kinetic precipitation simulation

International Nuclear Information System (INIS)

Ahmadi, M.R.; Povoden-Karadeniz, E.; Whitmore, L.; Stockinger, M.; Falahati, A.; Kozeschnik, E.

2014-01-01

The yield strength of Allvac ® 718Plus ™ during aging is computed using integrated physical models that take into account intrinsic, grain boundary, solid solution and precipitate strengthening contributions. Precipitation strengthening of γ′ has the main effect on the final yield strength in this alloy during aging, with the coherency and anti-phase boundary effects providing the major strengthening contributions. We utilize transmission electron microscopy to obtain the unknown physical parameters entering the strengthening models and compare precipitate size and distribution with the simulation results

Withdrawal Strength and Bending Yield Strength of Stainless Steel Nails

Science.gov (United States)

Douglas R. Rammer; Samuel L. Zelinka

2015-01-01

It has been well established that stainless steel nails have superior corrosion performance compared to carbon steel or galvanized nails in treated wood; however, their mechanical fastening behavior is unknown. In this paper, the performance of stainless steel nails is examined with respect to two important properties used in wood connection design: withdrawal strength...

Correlation of yield strength with irradiation-induced microstructure in AISI 316 stainless steel

International Nuclear Information System (INIS)

Simons, R.L.; Hulbert, L.A.

1985-10-01

Improvements in the correlation of radiation-induced change in yield strength in AISI 316 stainless steel with microstructure were made by re-examining the role of short-range obstacles. Effects due to the size of the obstacles relative to their spacing and shape of the obstacles were applied. The concept of shearing the precipitates instead of bowing around them was used to explain the effects of precipitate hardening. It is concluded that large changes in yield strength may be produced in high swelling materials. Voids will dominate the hardening at high dpa. The increase in hardening will depend on the diameter of the voids even though the swelling in the material is the same. Precipitate hardening at high fluence (>15 dpa) make a significant contribution for irradiation temperatures above 500 0 C

Are only Emotional Strengths Emotional? Character Strengths and Disposition to Positive Emotions.

Science.gov (United States)

Güsewell, Angelika; Ruch, Willibald

2012-07-01

This study aimed to examine the relations between character strengths and dispositional positive emotions (i.e. joy, contentment, pride, love, compassion, amusement, and awe). A sample of 574 German-speaking adults filled in the Dispositional Positive Emotion Scales (DPES; Shiota, Keltner, & John, 2006), and the Values in Action Inventory of Strengths (VIA-IS; Peterson, Park, & Seligman, 2005). The factorial structure of the DPES was examined on item level. Joy and contentment could not be clearly separated; the items of the other five emotions loaded on separate factors. A confirmatory factor analysis assuming two latent factors (self-oriented and object/situation specific) was computed on scale level. Results confirmed the existence of these factors, but also indicated that the seven emotions did not split up into two clearly separable families. Correlations between dispositional positive emotions and character strengths were positive and generally low to moderate; a few theoretically meaningful strengths-emotions pairs yielded coefficients>.40. Finally, the link between five character strengths factors (i.e. emotional strengths, interpersonal strengths, strengths of restraint, intellectual strengths, and theological strengths) and the emotional dispositions was examined. Each of the factors displayed a distinctive "emotional pattern"; emotional strengths evidenced the most numerous and strongest links to emotional dispositions. © 2012 The Authors. Applied Psychology: Health and Well-Being © 2012 The International Association of Applied Psychology.

Determination of the compressive yield strength for nano-grained YAG transparent ceramic by XRD analysis

International Nuclear Information System (INIS)

Wang, H.M.; Jiang, J.S.; Huang, Z.Y.; Chen, Y.; Liu, K.; Lu, Z.W.; Qi, J.Q.; Li, F.; He, D.W.; Lu, T.C.; Wang, Q.Y.

2016-01-01

Nano-grained ceramics have their unique mechanical characteristics that are not commonly found in their coarse-grained counterparts. In this study, nano-grained YAG transparent ceramics (NG-YAG) were prepared by low-temperature high-pressure technique (LTHP). The peak profile analysis of the X-ray diffraction was employed to investigate the compressive yield strength of NG-YAG. During the temperature at 450 °C, the residual micro-strain (RMS) increased with increasing loading pressure. However when the loading pressure was exceeded to 4.0 GPa the RMS exhibited a severe negative slop. The temperature effects on the compressive yield strength were also studied. It shows that the compressive yield strength of NG-YAG is 4.0 GPa and 5.0 GPa respectively at 450 °C and 350 °C. More importantly according to this investigation, a feasible technique to study the nano-grained ceramics is provided. - Graphical abstract: Fig. 2 shows the significant slope changes of calculated residual micro-strain (RMS) associated with five selected pressure-temperature conditions. Another the grain size estimated from Scherrer's formula, especially when it changes with the pressure-temperature condition is also plotted in Fig. 2. - Highlights: • Prepared the nano-grained YAG transparent ceramic by high pressure technique. • Obtained the compressive yield with different temperature. • Obtained the compressive yield of nano-grained YAG transparent ceramic.

Yield strength of molybdenum, tantalum and tungsten at high strain rates and very high temperatures

International Nuclear Information System (INIS)

Škoro, G.P.; Bennett, J.R.J.; Edgecock, T.R.; Booth, C.N.

2012-01-01

Highlights: ► New experimental data on the yield strength of molybdenum, tantalum and tungsten. ► High strain rate effects at record high temperatures (up to 2700 K). ► Test of the consistency of the Zerilli–Armstrong model at very high temperatures. - Abstract: Recently reported results of the high strain rate, high temperature measurements of the yield strength of tantalum and tungsten have been analyzed along with new experimental results on the yield strength of molybdenum. Thin wires are subjected to high stress by passing a short, fast, high current pulse through a thin wire; the amplitude of the current governs the stress and the repetition rate of the pulses determines the temperature of the wire. The highest temperatures reached in the experiments were 2100 °C (for molybdenum), 2250 °C (for tantalum) and 2450 °C (for tungsten). The strain-rates in the tests were in the range from 500 to 1500 s −1 . The parameters for the constitutive equation developed by Zerilli and Armstrong have been determined from the experimental data and the results have been compared with the data obtained at lower temperatures. An exceptionally good fit is obtained for the deformation of tungsten.

Garnet Yield Strength at High Pressures and Implications for Upper Mantle and Transition Zone Rheology

International Nuclear Information System (INIS)

Kavner, A.

2008-01-01

Garnet helps control the mechanical behavior of the Earth's crust, mantle, and transition zone. Here, measurements are presented suggesting that garnet, long considered to be a high-viscosity phase, is actually weaker than the other dominant components in the transition zone. The mechanical behavior of garnet at high pressures was examined using radial diffraction techniques in the diamond anvil cell. The yield strength of grossular garnet was inferred from synchrotron X-ray measurements of differential lattice strains. The differential stress was found to increase from 1.3 (±0.6) GPa at a hydrostatic pressure 5.8 (±1.1) GPa to 4.1 (±0.4) GPa at 15.7 (±1.0) GPa, where it was level to 19 GPa. The strength results are consistent with inferred strength values for majorite garnet from measurements in the diamond cell normal geometry, bolstering the idea that garnet-structured materials may all have similar strengths. In this low-temperature, high differential stress regime, garnet is shown to be significantly weaker than anhydrous ringwoodite and to have a strength similar to hydrous ringwoodite. This result suggests that the presence of water in the transition zone may not be required to explain a weak rheology, and therefore models of transition zone behavior built assuming that garnet is the high-strength phase may need to be revised.

Study of MA Effect on Yield Strength and Ductility of X80 Linepipe Steels Weld

Science.gov (United States)

Huda, Nazmul; Lazor, Robert; Gerlich, Adrian P.

2017-09-01

Multipass GMAW (Gas Metal Arc Welding) welding was used to join X80 linepipe materials using two weld metals of slightly different compositions. Welding wires with diameters of 0.984 and 0.909 mm were used while applying the same heat input in each pass. The slight difference in the wire diameters resulted in different HAZ microstructures. The microstructures in the doubly reheated HAZ of both welds were found to contain bainite-ferrite. However, etching also revealed a difference in martensite-austenite (MA) fraction in these reheated zones. The MA exhibited twice the hardness of ferrite when measured by nanoindentation. Tensile testing from the reheated zone of both welds revealed a difference in yield strength, tensile strength and elongation of the transverse weld specimens. In the reheated zone of weld A, (produced with a 0.984 mm wire) a higher fraction of MA was observed, which resulted in higher strength but lower elongation compared to weld B. The ductility of weld A was found severely impaired (to nearly half of weld B) due to formation of closely spaced voids around the MA, along with debonding of MA from the matrix, which occurs just above the yield stress.

Strength-ductility relationships in intermediate purity hot-pressed beryllium

International Nuclear Information System (INIS)

Stonehouse, A.J.; Bielawski, C.A.; Paine, R.M.

1977-01-01

The strength of vacuum hot-pressed, intermediate purity beryllium may be substantially increased without sacrifice of the strain capacity of the present grade (S-65) through decrease in the average grain size. Tensile strength of 517 MPa, 0.2% offset yield strength of 414 MPa with minimum 3% tensile elongation in all test directions could be commercially achieved. The tangent modulus of such material is quite attractive and suffers only about 10% degradation from room temperature to 260 0 C. The tangent modulus is dramatically enhanced by the presence of a yield point. The ductility of the materials studied did not appear to be affected by the BeO content across the range of 0.5 to 2.0% using nominal -44 to -15 μm powder particle sizes. All fine-grained pressings exhibited yield points in the as-pressed condition. Either full-density or sub-density hot-pressed billets given a hot isostatic pressing treatment without the use of cans showed only slight yield points after the HIP treatment with essentially the same strength and ductility factors as in the pressed condition. A plot of grain size vs yield strength in the as-pressed condition projects to an intercept with the fracture strength line at about 3 μm grain size. A similar plot after the HIP treatment shows a yield strength line parallel to the fracture strength line with no projected intercept predicting a completely brittle material. (author)

Burst strength of tubing and casing based on twin shear unified strength theory.

Science.gov (United States)

Lin, Yuanhua; Deng, Kuanhai; Sun, Yongxing; Zeng, Dezhi; Liu, Wanying; Kong, Xiangwei; Singh, Ambrish

2014-01-01

The internal pressure strength of tubing and casing often cannot satisfy the design requirements in high pressure, high temperature and high H2S gas wells. Also, the practical safety coefficient of some wells is lower than the design standard according to the current API 5C3 standard, which brings some perplexity to the design. The ISO 10400: 2007 provides the model which can calculate the burst strength of tubing and casing better than API 5C3 standard, but the calculation accuracy is not desirable because about 50 percent predictive values are remarkably higher than real burst values. So, for the sake of improving strength design of tubing and casing, this paper deduces the plastic limit pressure of tubing and casing under internal pressure by applying the twin shear unified strength theory. According to the research of the influence rule of yield-to-tensile strength ratio and mechanical properties on the burst strength of tubing and casing, the more precise calculation model of tubing-casing's burst strength has been established with material hardening and intermediate principal stress. Numerical and experimental comparisons show that the new burst strength model is much closer to the real burst values than that of other models. The research results provide an important reference to optimize the tubing and casing design of deep and ultra-deep wells.

Implications of a visco-elastic model of the lithosphere for calculating yield strength envelopes

NARCIS (Netherlands)

Ershov, A.V.; Stephenson, R.A.

2006-01-01

The dominant deformation mechanism in the ductile part of the lithosphere is creep. From a mechanical point of view, creep can be modelled as a viscous phenomenon. On the other hand, yield-strength envelopes (YSEs), commonly used to describe lithosphere rheology, are constructed supposing creep to

Measurement of the yield and tensile strengths of neutron-irradiated and post-irradiation recovered vessel steels with notched specimens

International Nuclear Information System (INIS)

Valiente, A.

1996-01-01

Tensile circumferentially notched bars are examined as test specimens for measuring the yield and tensile strengths of nuclear pressure vessel steels under several conditions of irradiation and temperature that a vessel can experience during its service life, including recovery post-irradiation treatment. For all the vessel steels, notch geometries and conditions explored, it has been found that notched specimens fail by plastic collapse, and simple formulae have been derived that allow the yield and tensile strengths to be determined from the yielding and plastic collapse load of a notched specimen. Values measured in this way show good agreement with those measured by the standard tensile test method. (orig.)

Yield and strength properties of the Ti-6-22-22S alloy over a wide strain rate and temperature range

International Nuclear Information System (INIS)

Krueger, L.; Kanel, G.I.; Razorenov, S.V.; Bezrouchko, G.S.; Meyer, L.

2002-01-01

A mechanical behavior of the Ti-6-22-22S alloy was studied under uniaxial strain conditions at shock-wave loading and under uniaxial compressive stress conditions over a strain rate range of 10-4 s-1 to 103 s-1. The test temperature was varied from -175 deg. C to 620 deg. C. The strain-rate and the temperature dependencies of the yield stress obtained from the uniaxial stress tests and from the shock-wave experiments are in a good agreement and demonstrate a significant decrease in the yield strength as the temperature increases. This indicates the thermal activation mechanism of plastic deformation of the alloy is maintained at strain rates up to 106 s-1. Variation of sample thickness from 2.24 to 10 mm results in relatively small variations in the dynamic yield strength and the spall strength over the whole temperature range

Strong morphological and crystallographic texture and resulting yield strength anisotropy in selective laser melted tantalum

International Nuclear Information System (INIS)

Thijs, Lore; Montero Sistiaga, Maria Luz; Wauthle, Ruben; Xie, Qingge; Kruth, Jean-Pierre; Van Humbeeck, Jan

2013-01-01

Selective laser melting (SLM) makes use of a high energy density laser beam to melt successive layers of metallic powders in order to create functional parts. The energy density of the laser is high enough to melt refractory metals like Ta and produce mechanically sound parts. Furthermore, the localized heat input causes a strong directional cooling and solidification. Epitaxial growth due to partial remelting of the previous layer, competitive growth mechanism and a specific global direction of heat flow during SLM of Ta result in the formation of long columnar grains with a 〈1 1 1〉 preferential crystal orientation along the building direction. The microstructure was visualized using both optical and scanning electron microscopy equipped with electron backscattered diffraction and the global crystallographic texture was measured using X-ray diffraction. The thermal profile around the melt pool was modeled using a pragmatic model for SLM. Furthermore, rotation of the scanning direction between different layers was seen to promote the competitive growth. As a result, the texture strength increased to as large as 4.7 for rotating the scanning direction 90° every layer. By comparison of the yield strength measured by compression tests in different orientations and the averaged Taylor factor calculated using the viscoplastic self-consistent model, it was found that both the morphological and crystallographic texture observed in SLM Ta contribute to yield strength anisotropy

Creep strength and rupture ductility of creep strength enhanced ferritic steels

Energy Technology Data Exchange (ETDEWEB)

Kushima, Hideaki; Sawada, Kota; Kimura, Kazuhiro [National Inst. for Materials Science, Tsukuba, Ibaraki (Japan)

2010-07-01

Creep strength and rupture ductility of Creep Strength Enhanced Ferritic (CSEF) steels were investigated from a viewpoint of stress dependence in comparison with conventional low alloy ferritic creep resistant steels. Inflection of stress vs. time to rupture curve was observed at 50% of 0.2% offset yield stress for both CSEF and conventional ferritic steels. Creep rupture ductility tends to decrease with increase in creep exposure time, however, those of conventional low alloy steels indicate increase in the long-term. Creep rupture ductility of the ASME Grades 92 and 122 steels indicates drastic decrease with decrease in stress at 50% of 0.2% offset yield stress. Stress dependence of creep rupture ductility of the ASME Grades 92 and 122 steels is well described by stress ratio to 0.2% offset yield stress, regardless of temperature. Drop of creep rupture ductility is caused by inhomogeneous recovery at the vicinity of prior austenite grain boundary, and remarkable drop of creep rupture ductility of CSEF steels should be derived from those stabilized microstructure. (orig.)

Effect of dislocation pile-up on size-dependent yield strength in finite single-crystal micro-samples

Energy Technology Data Exchange (ETDEWEB)

Pan, Bo; Shibutani, Yoji, E-mail: sibutani@mech.eng.osaka-u.ac.jp [Department of Mechanical Engineering, Osaka University, Suita 565-0871 (Japan); Zhang, Xu [State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi' an Jiaotong University, Xi' an 710049 (China); School of Mechanics and Engineering Science, Zhengzhou University, Zhengzhou 450001 (China); Shang, Fulin [State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi' an Jiaotong University, Xi' an 710049 (China)

2015-07-07

Recent research has explained that the steeply increasing yield strength in metals depends on decreasing sample size. In this work, we derive a statistical physical model of the yield strength of finite single-crystal micro-pillars that depends on single-ended dislocation pile-up inside the micro-pillars. We show that this size effect can be explained almost completely by considering the stochastic lengths of the dislocation source and the dislocation pile-up length in the single-crystal micro-pillars. The Hall–Petch-type relation holds even in a microscale single-crystal, which is characterized by its dislocation source lengths. Our quantitative conclusions suggest that the number of dislocation sources and pile-ups are significant factors for the size effect. They also indicate that starvation of dislocation sources is another reason for the size effect. Moreover, we investigated the explicit relationship between the stacking fault energy and the dislocation “pile-up” effect inside the sample: materials with low stacking fault energy exhibit an obvious dislocation pile-up effect. Our proposed physical model predicts a sample strength that agrees well with experimental data, and our model can give a more precise prediction than the current single arm source model, especially for materials with low stacking fault energy.

Soil strength and maize yield after topsoil removal and application of nutrient amendments on a gravelly Alfisol toposequence

International Nuclear Information System (INIS)

Salako, F.K.; Dada, P.O.; Adejuyigbe, C.O.; Adedire, M.O.; Martins, O.; Akwuebu, C.A.; Williams, O.E.

2006-04-01

Vast areas of degraded soils exist in southwestern Nigeria due to topsoil removal by soil erosion and gravel/stone mining operators. The restoration of such soils has become imperative to sustain food production in most rural communities. Therefore, a factorial field experiment was designed in 2003 and 2004 with the factors being slope positions (upper and lower slopes), topsoil removal (0, 15 and 25 cm depths) and nutrient amendments (0, 10 t ha -1 poultry manure and 60:30:30 N: P 2 O 5 : K 2 O as NPK + urea). This was complemented with a laboratory study to determine the effects of soil water, gravel concentration and gravel size on soil strength. Maize was planted. Soil strength was measured with a self-recoding penetrometer at soil depth interval of 2.5 cm up to 50 cm depth. Soil bulk density, water content, maize root and shoot biomass and grain yield were measured. In the laboratory, soil strength decreased from 483-314 kPa as water content increased from 0.05-0.62 cm 3 cm - 3 while it increased from 294-469 kPa as gravel concentration increased from 100-500 g kg -1 . Soil strength was affected more by water content and gravel concentration than gravel size. Under various moist conditions in the field, soil strength increased with soil depth from 1177-5000 kPa at the upper slope and from 526-5000 kPa at the lower slope. Thus, the lower slope had significantly lower soil strength than the upper slope. Soil strength increased with increasing soil depth removal and was significantly reduced by poultry manure. For the 2 years of study, high grain yields were sustained with poultry manure/no topsoil removal (1784-3571 kg ha -1 ) and NPK + urea/no topsoil removal (2371-2600 kPa) at the lower slope. However, soil at the upper slope was more resistant to degradation as 16-67% loss in yield was observed compared to 65-75% for lower slope when no nutrients were applied. Nonetheless, both the upper and lower slope positions were productive with the application of

Self-consistent technique for estimating the dynamic yield strength of a shock-loaded material

International Nuclear Information System (INIS)

Asay, J.R.; Lipkin, J.

1978-01-01

A technique is described for estimating the dynamic yield stress in a shocked material. This method employs reloading and unloading data from a shocked state along with a general assumption of yield and hardening behavior to estimate the yield stress in the precompressed state. No other data are necessary for this evaluation, and, therefore, the method has general applicability at high shock pressures and in materials undergoing phase transitions. In some special cases, it is also possible to estimate the complete state of stress in a shocked state. Using this method, the dynamic yield strength of aluminum at 2.06 GPa has been estimated to be 0.26 GPa. This value agrees reasonably well with previous estimates

Mapping strengths into virtues: The relation of the 24 VIA-strengths to six ubiquitous virtues

Directory of Open Access Journals (Sweden)

Willibald eRuch

2015-04-01

Full Text Available The Values-in-Action (VIA-classification distinguishes six core virtues and 24 strengths. As the assignment of the strengths to the virtues was done on theoretical grounds it still needs empirical verification. As an alternative to factor analytic investigations the present study utilizes expert judgments. In a pilot study the conceptual overlap among five sources of knowledge (strength’s name including synonyms, short definitions, brief descriptions, longer theoretical elaborations, and item content about a particular strength was examined. The results show that the five sources converged quite well, with the short definitions and the items being slightly different from the other. All strengths exceeded a cut-off value but the convergence was much better for some strengths (e.g., zest than for others (e.g., perspective. In the main study 70 experts (from psychology, philosophy, theology, etc. and 41 laypersons rated how prototypical the strengths are for each of the six virtues. The results showed that 10 were very good markers for their virtues, 9 were good markers, four were acceptable markers, and only one strength failed to reach the cut-off score for its assigned virtue. However, strengths were often markers for two or even three virtues, and occasionally they marked the other virtue more strongly than the one they were assigned to. The virtue prototypicality ratings were slightly positively correlated with higher coefficients being found for justice and humanity. A factor analysis of the 24 strengths across the ratings yielded the six factors with an only slightly different composition of strengths and double loadings. It is proposed to adjust either the classification (by reassigning strengths and by allowing strengths to be subsumed under more than one virtue or to change the definition of certain strengths so that they only exemplify one virtue. The results are discussed in the context of factor analytic attempts to verify the

Fracture strength of aluminium alloys under rapid loading conditions

International Nuclear Information System (INIS)

Joshi, K.D.; Rav, Amit S.; Sur, Amit; Kaushik, T.C.; Gupta, Satish C.

2016-04-01

Spall fracture strength and dynamic yield strength of aluminium alloys have been measured at high strain rates generated in plate impact experiments carried out at different impact velocities ranging from 174 m/s to 560 m/s using single stage gas gun facility. In each experiment, the free surface velocity history of the sample plate of aluminium alloy has been derived from time resolved Doppler shift measured employing indigenously developed velocity interferometer system for any reflector (VISAR). The free surface velocity history so determined has been used to evaluate the spall fracture strength and dynamic yield strength of the target material. The two kinds of alloys of aluminium namely Al2014-T4 and Al2024-T4 have been investigated in these experiments. In Al2014-T4 target plates, the spall strength determined from free surface velocity history recorded for impact velocities of 179 m/s, 307 m/s, 398 m/s and 495m/s is 0.90 GPa, 0.96 GPa, 1.0 GPa and 1.1 GPa, respectively. The average strain rates just ahead of spall pulse have been found to vary from ∼ 1.1×10 4 /s to 2.4×10 4 /s. The dynamic yield strength derived from the measured Hugoniot elastic limit ranges from 0.36 GPa to 0.40 GPa. The spall strength for Al2024-T4 samples has been determined to be 1.11 GPa, 1.18 GPa and 1.42 GPa, at impact velocities of 174 m/s, 377 m/s and 560 m/s, respectively. The corresponding average strain rates range from 1.9×104/s to 2.5×104/s. The dynamic yield strength of Al2024-T4 at these impact velocities has been found to vary from 0.37 GPa to 0.43 GPa. The measured spall strengths in all these experiments are higher than the quasi-static value of 0.511 GPa for Al2014-T4 and 0.470 GPa for Al2024. Similarly, the dynamic yield strengths are also larger than the quasi-static value of 0.355 GPa for Al2014-T4 and 0.360 GPa for Al2024-T4. These experimental studies suggest that at high strain rates, both the alloys of aluminium offer higher resistance against the tensile

Semi-quantitative evaluation of texture components and anisotropy of the yield strength in 2524 T3 alloy sheets

International Nuclear Information System (INIS)

Shen, Fanghua; Yi, Danqing; Wang, Bin; Liu, Huiqun; Jiang, Yong; Tang, Cong; Jiang, Bo

2016-01-01

Decreasing the anisotropy of 2524 alloys is a key factor for their use in applications such as high-performance inertial components or space robots. Studying the interaction between sheet textures and anisotropy is a key factor to overcome this problem. In this study, the semi-quantitative approach to estimate the relation between texture and in-plane anisotropy (IPA) of yield strength has been developed. The intensity ratio between Cube and Brass texture components (F CGB ) was used as an effective variable for this purpose. This approach has been tested in 2524 T3 aluminum alloy sheets, which were investigated using X-Ray diffraction, scanning electron microscopy, optical microscopy and tensile tests. The results show that F CGB decreased with an increase in cold reduction. The 2524 T3 sheet, dominated by Cube texture grains, possesses the lowest in-plane anisotropy for the yield strength of all texture components investigated. The alloy sheet dominated by Brass texture exhibits the highest anisotropy, while the Goss texture-led sheets fall in between them. These results agree with the trends seen in the factor F CGB , suggesting that is suited to evaluate the anisotropy of yield strength in 2524 T3 alloy sheets semi-quantitatively.

Semi-quantitative evaluation of texture components and anisotropy of the yield strength in 2524 T3 alloy sheets

Energy Technology Data Exchange (ETDEWEB)

Shen, Fanghua [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Yi, Danqing, E-mail: yioffice@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Light Alloy Research Institute, Central South University, Changsha, Hunan 410083 (China); National Collaborative Innovation Center of Advanced Nonferrous Structural Materials and Manufacturing, Central South University, Changsha 410083 (China); Wang, Bin; Liu, Huiqun; Jiang, Yong; Tang, Cong; Jiang, Bo [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

2016-10-15

Decreasing the anisotropy of 2524 alloys is a key factor for their use in applications such as high-performance inertial components or space robots. Studying the interaction between sheet textures and anisotropy is a key factor to overcome this problem. In this study, the semi-quantitative approach to estimate the relation between texture and in-plane anisotropy (IPA) of yield strength has been developed. The intensity ratio between Cube and Brass texture components (F{sub CGB}) was used as an effective variable for this purpose. This approach has been tested in 2524 T3 aluminum alloy sheets, which were investigated using X-Ray diffraction, scanning electron microscopy, optical microscopy and tensile tests. The results show that F{sub CGB} decreased with an increase in cold reduction. The 2524 T3 sheet, dominated by Cube texture grains, possesses the lowest in-plane anisotropy for the yield strength of all texture components investigated. The alloy sheet dominated by Brass texture exhibits the highest anisotropy, while the Goss texture-led sheets fall in between them. These results agree with the trends seen in the factor F{sub CGB}, suggesting that is suited to evaluate the anisotropy of yield strength in 2524 T3 alloy sheets semi-quantitatively.

STRENGTH OF NANOMODIFIED HIGH-STRENGTH LIGHTWEIGHT CONCRETES

Directory of Open Access Journals (Sweden)

NOZEMTСEV Alexandr Sergeevich

2013-02-01

Full Text Available The paper presents the results of research aimed at development of nanomodified high-strength lightweight concrete for construction. The developed concretes are of low average density and high ultimate compressive strength. It is shown that to produce this type of concrete one need to use hollow glass and aluminosilicate microspheres. To increase the durability of adhesion between cement stone and fine filler the authors offer to use complex nanodimensinal modifier based on iron hydroxide sol and silica sol as a surface nanomodifier for hollow microspheres. It is hypothesized that the proposed modifier has complex effect on the activity of the cement hydration and, at the same time increases bond strength between filler and cement-mineral matrix. The compositions for energy-efficient nanomodified high-strength lightweight concrete which density is 1300…1500 kg/m³ and compressive strength is 40…65 MPa have been developed. The approaches to the design of high-strength lightweight concrete with density of less than 2000 kg/m³ are formulated. It is noted that the proposed concretes possess dense homogeneous structure and moderate mobility. Thus, they allow processing by vibration during production. The economic and practical implications for realization of high-strength lightweight concrete in industrial production have been justified.

REPETITIVE STRENGTH AMONG STUDENTS OF AGE 14

Directory of Open Access Journals (Sweden)

Besim Halilaj

2014-06-01

Full Text Available The study involved 82 male students of the primary school “Qamil Ilazi” in Kaçanik-Kosovo.Four movement tests, which test the repetitive strength, were conducted: 1. Pull-up, 2. Sit-Up, 3. Back extension, 4. Push-up.The main goal of this study was to verify the actual motor status, respectively the component of the repetitive strength among students of age 14 of masculine gender. In addition to verifying the actual motor status, another objective was to verify the relationship between the variables employed.Basic statistical parameters show a distribution which is not significantly different from the normal distribution, yielded highly correlative values among the repetitive strength tests. Space factorization resulted in extracting two latent squares defined as repetitive strength of arms factor, and repetitive strength of body factor.

A combined neural network and mechanistic approach for the prediction of corrosion rate and yield strength of magnesium-rare earth alloys

Energy Technology Data Exchange (ETDEWEB)

Birbilis, N., E-mail: nick.birbilis@monash.ed [ARC Centre of Excellence for Design in Light Metals, Monash University (Australia); CAST Co-operative Research Centre, Monash University (Australia); Cavanaugh, M.K. [Department of Materials Science and Engineering, The Ohio State University (United States); Sudholz, A.D. [ARC Centre of Excellence for Design in Light Metals, Monash University (Australia); Zhu, S.M.; Easton, M.A. [CAST Co-operative Research Centre, Monash University (Australia); Gibson, M.A. [CSIRO Division of Process Science and Engineering (Australia)

2011-01-15

Research highlights: This study presents a body of corrosion data for a set of custom alloys and displays this in multivariable space. These alloys represent the next generation of Mg alloys for auto applications. The data is processed using an ANN model, which makes it possible to yield a single expression for prediction of corrosion rate (and strength) as a function of any input composition (of Ce, La or Nd between 0 and 6 wt.%). The relative influence of the various RE elements on corrosion is assessed, with the outcome that Nd additions can offer comparable strength with minimal rise in corrosion rate. The morphology and solute present in the eutectic region itself (as opposed to just the intermetallic presence) was shown - for the first time - to also be a key contributor to corrosion. The above approach sets the foundation for rational alloy design of alloys with corrosion performance in mind. - Abstract: Additions of Ce, La and Nd to Mg were made in binary, ternary and quaternary combinations up to {approx}6 wt.%. This provided a dataset that was used in developing a neural network model for predicting corrosion rate and yield strength. Whilst yield strength increased with RE additions, corrosion rates also systematically increased, however, this depended on the type of RE element added and the combination of elements added (along with differences in intermetallic morphology). This work is permits an understanding of Mg-RE alloy performance, and can be exploited in Mg alloy design for predictable combinations of strength and corrosion resistance.

A combined neural network and mechanistic approach for the prediction of corrosion rate and yield strength of magnesium-rare earth alloys

International Nuclear Information System (INIS)

Birbilis, N.; Cavanaugh, M.K.; Sudholz, A.D.; Zhu, S.M.; Easton, M.A.; Gibson, M.A.

2011-01-01

Research highlights: → This study presents a body of corrosion data for a set of custom alloys and displays this in multivariable space. These alloys represent the next generation of Mg alloys for auto applications. → The data is processed using an ANN model, which makes it possible to yield a single expression for prediction of corrosion rate (and strength) as a function of any input composition (of Ce, La or Nd between 0 and 6 wt.%). → The relative influence of the various RE elements on corrosion is assessed, with the outcome that Nd additions can offer comparable strength with minimal rise in corrosion rate. → The morphology and solute present in the eutectic region itself (as opposed to just the intermetallic presence) was shown - for the first time - to also be a key contributor to corrosion. → The above approach sets the foundation for rational alloy design of alloys with corrosion performance in mind. - Abstract: Additions of Ce, La and Nd to Mg were made in binary, ternary and quaternary combinations up to ∼6 wt.%. This provided a dataset that was used in developing a neural network model for predicting corrosion rate and yield strength. Whilst yield strength increased with RE additions, corrosion rates also systematically increased, however, this depended on the type of RE element added and the combination of elements added (along with differences in intermetallic morphology). This work is permits an understanding of Mg-RE alloy performance, and can be exploited in Mg alloy design for predictable combinations of strength and corrosion resistance.

Plane strain fracture toughness tests on 2.4 and 3.9-inch-thick maraging steel specimens at various yield strength levels.

Science.gov (United States)

Fisher, D. M.; Repko, A. J.

1972-01-01

Tests of bend and compact specimens were conducted according to ASTM Tentative Method E 399-70T on a 200 grade maraging steel over a range of yield strengths from 123 to 234 ksi. The toughness of any given yield strength level was greater for the overaged condition than for the underaged. Some results which met the specimen size requirements of the method were distinctly lower than corresponding results from larger specimens. Inconsistencies in both validation and invalidation of results by the requirement for linearity of the test record were also noted.

Impact strength on fiber-reinforced hybrid composite

International Nuclear Information System (INIS)

Firdaus, S M; Nurdina; Ariff, M Azmil

2013-01-01

Acrylonitrile-Butadiene-Styrene (ABS) has been well known composite in automotive players to have light weight with high impact strength material compared to sheet metal material which has high impact strength but heavy in weight. In this project, the impact strength properties of fabricated pure ABS were compared to the eight samples of hybrid ABS composite with different weight percentages of short fibers and particle sizes of ground rubber. The objective was to improve the impact strength in addition of short fibers and ground rubber particles. These samples were then characterized using an un-notched Izod impact test. Results show that the increasing of filler percentage yielded an adverse effect on the impact strength of the hybrid composite. The effect of the ground rubber particulate sizes however are deemed to be marginal than the effect of varying filler percentage based on the collected impact strength data from all physically tested hybrid composites

Strength gradient enhances fatigue resistance of steels

Science.gov (United States)

Ma, Zhiwei; Liu, Jiabin; Wang, Gang; Wang, Hongtao; Wei, Yujie; Gao, Huajian

2016-02-01

Steels are heavily used in infrastructure and the transportation industry, and enhancing their fatigue resistance is a major challenge in materials engineering. In this study, by introducing a gradient microstructure into 304 austenitic steel, which is one of the most widely used types of stainless steel, we show that a strength gradient substantially enhances the fatigue life of the material. Pre-notched samples with negative strength gradients in front of the notch’s tip endure many more fatigue cycles than do samples with positive strength gradients during the crack initiation stage, and samples with either type of gradient perform better than do gradient-free samples with the same average yield strength. However, as a crack grows, samples with positive strength gradients exhibit better resistance to fatigue crack propagation than do samples with negative gradients or no gradient. This study demonstrates a simple and promising strategy for using gradient structures to enhance the fatigue resistance of materials and complements related studies of strength and ductility.

Unified strength theory and its applications

CERN Document Server

Yu, Mao-Hong

2004-01-01

This is a completely new theory dealing with the yield and failure of materials under multi-axial stresses. It provides a system of yield and failure criteria adopted for most materials, from metallic materials to rocks, concretes, soils, polymers etc. The Unified Strength Theory has been applied successfully to analyse the elastic limit, plastic limit capacities, the dynamic response behavior for some structures under static and moderate impulsive load, and may be implemented in some elasto-plastic finite element computer codes. The Unified Strength Theory is described in detail and by using this theory a series of results can be obtained. The Unified Strength Theory can improve the conservative Mohr-Coulomb Theory, and since intermediate principal stress is not taken into account in the Mohr-Coulomb theory and most experimental data is not pertainable to the Mohr-Coulomb Theory, a considerable economic benefit may be obtained. The book can also increase the effect of most commercial finite element computer ...

Elementary and advanced modelling of the splitting strength of timber connections

NARCIS (Netherlands)

Schoenmakers, J.C.M.D.

2008-01-01

The load-bearing capacity of a timber member loaded perpendicular-to-grain by a connection is governed by either the embedment strength, the bending yield strength of the steel fasteners, or the splitting strength of the timber. Only coarse models for predicting the splitting strength are

Experimental Investigation on Embedding Strength Perpendicular to Grain of Parallel Strand Bamboo

Directory of Open Access Journals (Sweden)

Junwen Zhou

2018-01-01

Full Text Available Parallel strand bamboo (PSB is a latest construction material; to know more about mechanical properties of PSB, 5 groups of specimens with difference only in bolt diameter were designed to study the impact of the fastener diameter on embedding strength perpendicular to grain of PSB. Based on the tested result, the feasibility for PSB of the theoretical equation in the American code and European code on embedding strength predication was assessed. A controlled displacement was used to load till specimen failure, the stress-displacement curve of all specimens was obtained in terms of the tested results, and the yielding tested strength based on 5% bolt diameter offset proposed by the American code was found. The tested results showed that the yielding strength perpendicular to grain of PSB was stable, the variable coefficient was between 5.88% and 13.34%, and the average yielding strength values were 80.84 MPa, 77.40 MPa, 76.52 MPa, 74.20 MPa, and 67.01 MPa, respectively, which decreased with the increase of bolt diameter, and the average yielding strength values are larger than the calculated results using theoretical formula. Therefore, the theoretical equation on embedding yielding strength of wood in the American code and European code applies to PSB.

Energy-Based Yield Criteria for Orthotropic Materials, Exhibiting Strength-Differential Effect. Specification for Sheets under Plane Stress State

Directory of Open Access Journals (Sweden)

Szeptyński P.

2017-06-01

Full Text Available A general proposition of an energy-based limit condition for anisotropic materials exhibiting strength-differential effect (SDE based on spectral decomposition of elasticity tensors and the use of scaling pressure-dependent functions is specified for the case of orthotropic materials. A detailed algorithm (based on classical solutions of cubic equations for the determination of elastic eigenstates and eigenvalues of the orthotropic stiffness tensor is presented. A yield condition is formulated for both two-dimensional and three-dimensional cases. Explicit formulas based on simple strength tests are derived for parameters of criterion in the plane case. The application of both criteria for the description of yielding and plastic deformation of metal sheets is discussed in detail. The plane case criterion is verified with experimental results from the literature.

Dual characteristics of yield and ultimate strength as applied to two grades of beryllium

International Nuclear Information System (INIS)

Priddy, T.G.; Benzley, S.E.; Johnson, R.L.

1977-02-01

Published yield and ultimate biaxial strength data for two grades of beryllium are correlated with the use of a macroscopic failure model. Cross sections of the resulting surfaces in three-dimensional stress space are drawn to illustrate the expected transition from ductile to brittle fracture for triaxial tension states of stress. The usefulness of these models to the prediction of fracture in ductile materials is discussed. 5 tables, 8 figures, 11 references

The Strength Compass

DEFF Research Database (Denmark)

Ledertoug, Mette Marie

In the Ph.D-project ͚Strengths-based Learning - Children͛s character strengths as a means to their learning potential͛ 750 Danish children have assessed ͚The Strength Compass͛ in order to identify their strengths and to create awareness of strengths. This was followed by a strengths......-based intervention program in order to explore the strengths. Finally different methods to apply the strength in everyday life at school were applied. The paper presentation will show the results for strengths display for children aged 6-16 in different categories: Different age groups: Are the same strengths...... present in both small children and youths? Gender: Do the results show differences between the two genders? Danish as a mother- tongue language: Do the results show any differences in the strengths display when considering different language and cultural backgrounds? Children with Special Needs: Do...

The Character Strengths of Class Clowns

Directory of Open Access Journals (Sweden)

Willibald F. Ruch

2014-09-01

Full Text Available Class clowns traditionally were studied as a type concept and identified via sociometric procedures. In the present study a variable-centered approach was favored and class clown behaviors were studied in the context of character strengths, orientations to happiness and satisfaction with life. A sample of 672 Swiss children and adolescents filled in an 18 item self-report instrument depicting class clown behaviors. A hierarchical model of class clown behaviors was developed distinguishing a general factor and the four positively correlated dimensions of identified as a class clown, comic talent, disruptive rule-breaker, and subversive joker. Analysis of the general factor showed that class clowns were primarily male, and tended to be seen as class clowns by the teacher. Analyses of the 24 character strengths of the VIA-Youth (Park & Peterson, 2006 showed that class clowns were high in humor and leadership, and low in strengths like prudence, self-regulation, modesty, honesty, fairness, perseverance, and love of learning. An inspection of signature strengths revealed that 75% of class clowns had humor as a signature strength. Furthermore, generally class clown behaviors were shown by students indulging in a life of pleasure, but low life of engagement. The four dimensions yielded different character strengths profiles. While all dimensions of class clowns behaviors were low in temperance strengths, the factors identified as the class clown and comic talent were correlated with leadership strengths and the two negative factors (disruptive rule-breaker, subversive joker were low in other directed strengths. The disruptive rule breaking class clown was additionally low in intellectual strengths. While humor predicted life satisfaction, class clowning tended to go along with diminished satisfaction with life. It is concluded that different types of class clowns need to be kept apart and need different attention by teachers.

The character strengths of class clowns.

Science.gov (United States)

Ruch, Willibald; Platt, Tracey; Hofmann, Jennifer

2014-01-01

Class clowns traditionally were studied as a type concept and identified via sociometric procedures. In the present study a variable-centered approach was favored and class clown behaviors were studied in the context of character strengths, orientations to happiness and satisfaction with life. A sample of 672 Swiss children and adolescents filled in an 18 item self-report instrument depicting class clown behaviors. A hierarchical model of class clown behaviors was developed distinguishing a general factor and the four positively correlated dimensions of "identified as a class clown," "comic talent," "disruptive rule-breaker," and "subversive joker." Analysis of the general factor showed that class clowns were primarily male, and tended to be seen as class clowns by the teacher. Analyses of the 24 character strengths of the VIA-Youth (Park and Peterson, 2006) showed that class clowns were high in humor and leadership, and low in strengths like prudence, self-regulation, modesty, honesty, fairness, perseverance, and love of learning. An inspection of signature strengths revealed that 75% of class clowns had humor as a signature strength. Furthermore, class clown behaviors were generally shown by students indulging in a life of pleasure, but low life of engagement. The four dimensions yielded different character strengths profiles. While all dimensions of class clowns behaviors were low in temperance strengths, the factors "identified as the class clown" and "comic talent" were correlated with leadership strengths and the two negative factors ("disruptive rule-breaker," "subversive joker") were low in other directed strengths. The disruptive rule breaking class clown was additionally low in intellectual strengths. While humor predicted life satisfaction, class clowning tended to go along with diminished satisfaction with life. It is concluded that different types of class clowns need to be kept apart and need different attention by teachers.

Strengths only or strengths and relative weaknesses? A preliminary study.

Science.gov (United States)

Rust, Teri; Diessner, Rhett; Reade, Lindsay

2009-10-01

Does working on developing character strengths and relative character weaknesses cause lower life satisfaction than working on developing character strengths only? The present study provides a preliminary answer. After 76 college students completed the Values in Action Inventory of Strengths (C. Peterson & M. E. P. Seligman, 2004), the authors randomly assigned them to work on 2 character strengths or on 1 character strength and 1 relative weakness. Combined, these groups showed significant gains on the Satisfaction With Life Scale (E. Diener, R. A. Emmons, R. J. Larsen, & S. Griffin, 1985), compared with a 32-student no-treatment group. However, there was no significant difference in gain scores between the 2-strengths group and the 1-character-strength-and-1-relative-character-weakness group. The authors discuss how focusing on relative character weaknesses (along with strengths) does not diminish-and may assist in increasing-life satisfaction.

Characteristics of structural loess strength and preliminary framework for joint strength formula

OpenAIRE

Rong-jian Li; Jun-ding Liu; Rui Yan; Wen Zheng; Sheng-jun Shao

2014-01-01

The strength of structural loess consists of the shear strength and tensile strength. In this study, the stress path, the failure envelope of principal stress (Kf line), and the strength failure envelope of structurally intact loess and remolded loess were analyzed through three kinds of tests: the tensile strength test, the uniaxial compressive strength test, and the conventional triaxial shear strength test. Then, in order to describe the tensile strength and shear strength of structural lo...

The strength compass

DEFF Research Database (Denmark)

Ledertoug, Mette Marie

of agreement/disagreement. Also the child/teacher is asked whether the actual strength is important and if he or she has the possibilities to apply the strength in the school. In a PhDproject ‘Strengths-based Learning - Children’s Character Strengths as Means to their Learning Potential’ 750 Danish children......Individual paper presentation: The ‘Strength Compass’. The results of a PhDresearch project among schoolchildren (age 6-16) identifying VIAstrengths concerning age, gender, mother-tongue-langue and possible child psychiatric diagnosis. Strengths-based interventions in schools have a theoretical...... Psychological Publishing Company. ‘The Strength Compass’ is a computer/Ipad based qualitative tool to identify the strengths of a child by a self-survey or a teacher’s survey. It is designed as a visual analogue scale with a statement of the strength in which the child/teacher may declare the degree...

Short-term Periodization Models: Effects on Strength and Speed-strength Performance.

Science.gov (United States)

Hartmann, Hagen; Wirth, Klaus; Keiner, Michael; Mickel, Christoph; Sander, Andre; Szilvas, Elena

2015-10-01

Dividing training objectives into consecutive phases to gain morphological adaptations (hypertrophy phase) and neural adaptations (strength and power phases) is called strength-power periodization (SPP). These phases differ in program variables (volume, intensity, and exercise choice or type) and use stepwise intensity progression and concomitant decreasing volume, converging to peak intensity (peaking phase). Undulating periodization strategies rotate these program variables in a bi-weekly, weekly, or daily fashion. The following review addresses the effects of different short-term periodization models on strength and speed-strength both with subjects of different performance levels and with competitive athletes from different sports who use a particular periodization model during off-season, pre-season, and in-season conditioning. In most periodization studies, it is obvious that the strength endurance sessions are characterized by repetition zones (12-15 repetitions) that induce muscle hypertrophy in persons with a low performance level. Strictly speaking, when examining subjects with a low training level, many periodization studies include mainly hypertrophy sessions interspersed with heavy strength/power sessions. Studies have demonstrated equal or statistically significant higher gains in maximal strength for daily undulating periodization compared with SPP in subjects with a low to moderate performance level. The relatively short intervention period and the lack of concomitant sports conditioning call into question the practical value of these findings for competitive athletes. Possibly owing to differences in mesocycle length, conditioning programs, and program variables, competitive athletes either maintained or improved strength and/or speed-strength performance by integrating daily undulating periodization and SPP during off-season, pre-season and in-season conditioning. In high-performance sports, high-repetition strength training (>15) should be

Strength and ductility of Ni3Al alloyed with boron and substitutional elements

International Nuclear Information System (INIS)

Ishikawa, K.; Aoki, K.; Masumoto, T.

1995-01-01

The effect of simultaneous alloying of boron (B) and the substitutional elements M on mechanical properties of Ni 3 Al was investigated by the tensile test at room temperature. The yield strength of Ni 3 Al+B increases by alloying with M except for Fe and Ga. In particular, it increases by alloying with Hf, Nb, W, Ta, Pd and Si. The fracture strength of Ni 3 Al+B increases by alloying with Pd, Ga, Si and Hf, but decreases with the other elements. Elongation of Ni 3 Al+B increases by alloying with Ga, Fe and Pd, but decreases with other elements. Hf and Pd is the effective element for the increase of the yield strength and the fracture strength of Ni 3 Al+B, respectively. Alloying with Hf leads to the increases of the yield strength and the fracture strength of Ni 3 Al+B, but to the lowering of elongation. On the other hand, alloying with Pd improves all mechanical properties, i.e. the yield strength, the fracture strength and elongation. On the contrary, alloying with Ti, V and Co leads to the lowering of mechanical properties of Ni 3 Al+B. The reason why ductility of Ni 3 Al+B is reduced by alloying with some elements M is discussed

Heliospheric Modulation Strength During The Neutron Monitor Era

Science.gov (United States)

Usoskin, I. G.; Alanko, K.; Mursula, K.; Kovaltsov, G. A.

Using a stochastic simulation of a one-dimensional heliosphere we calculate galactic cosmic ray spectra at the Earth's orbit for different values of the heliospheric mod- ulation strength. Convoluting these spectra with the specific yield function of a neu- tron monitor, we obtain the expected neutron monitor count rates for different values of the modulation strength. Finally, inverting this relation, we calculate the modula- tion strength using the actually recorded neutron monitor count rates. We present the reconstructed annual heliospheric modulation strengths for the neutron monitor era (1953­2000) using several neutron monitors from different latitudes, covering a large range of geomagnetic rigidity cutoffs from polar to equatorial regions. The estimated modulation strengths are shown to be in good agreement with the corresponding esti- mates reported earlier for some years.

Beam Test for Evaluating Applicabillity of High - Strength Reinforcement in Structure of Nuclear Facility

International Nuclear Information System (INIS)

Yim, Sangjun; Lee, Byungsoo; Bang, Changjoon

2014-01-01

The high-strength rebar which has high yield strength can reduce the amount of rebar in concrete and widen its spacing so that it has better workability and higher economic benefits for the structure. However, the maximum yield strength of rebar is limited to 420MPa in the design criteria for structure of nuclear facility in Korea and USA. Korea Hydro and Nuclear Power is progressing research to revise the limitation in the yield strength of rebar, which is suggested in the criteria of KEPIC and ACI, in order to apply 550 MPa high-strength rebar for the construction of a nuclear facility. This study is to review the applicability of high strength rebar in structure of a nuclear facility through a model beam test. After reviewing the shear capacity and reinforcement yield to assess the applicability of high-strength reinforcement in the structure of a nuclear facility, we make the following conclusions. When using high shear reinforcement with wider spacing, it has a similar shear capacity to normal reinforcement with narrower spacing. This means better workability and economic benefits can be achieved by widening the rebar spacing without brittle fracture in the elements. For future plans, the results of this test and supplementary test will be submitted to ACI349 committee as backup data to revise the standard for yield strength of high-strength rebar

Beam Test for Evaluating Applicabillity of High - Strength Reinforcement in Structure of Nuclear Facility

Energy Technology Data Exchange (ETDEWEB)

Yim, Sangjun; Lee, Byungsoo; Bang, Changjoon [Korea Hydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of)

2014-05-15

The high-strength rebar which has high yield strength can reduce the amount of rebar in concrete and widen its spacing so that it has better workability and higher economic benefits for the structure. However, the maximum yield strength of rebar is limited to 420MPa in the design criteria for structure of nuclear facility in Korea and USA. Korea Hydro and Nuclear Power is progressing research to revise the limitation in the yield strength of rebar, which is suggested in the criteria of KEPIC and ACI, in order to apply 550 MPa high-strength rebar for the construction of a nuclear facility. This study is to review the applicability of high strength rebar in structure of a nuclear facility through a model beam test. After reviewing the shear capacity and reinforcement yield to assess the applicability of high-strength reinforcement in the structure of a nuclear facility, we make the following conclusions. When using high shear reinforcement with wider spacing, it has a similar shear capacity to normal reinforcement with narrower spacing. This means better workability and economic benefits can be achieved by widening the rebar spacing without brittle fracture in the elements. For future plans, the results of this test and supplementary test will be submitted to ACI349 committee as backup data to revise the standard for yield strength of high-strength rebar.

High-strength chromium--molybdenum rails

International Nuclear Information System (INIS)

Smith, Y.E.; Sawhill, J.M. Jr.; Cias, W.W.; Eldis, G.T.

1976-01-01

A laboratory study was conducted with the aim of developing an as-rolled rail of over 100 ksi (689 N/mm 2 ) yield strength. A series of compositions providing both pearlitic and bainitic microstructures was evaluated. A fine pearlitic structure was developed in a 0.73 percent C -- 0.83 percent Mn -- 0.16 percent Si -- 0.75 percent Cr -- 0.21 percent Mo steel by simulating the mill cooling rate of 132-lb/yd (65.5-kg/m) rail. Two 100-ton commercial heats were made of this approximate composition and processed into 132-lb/yd (65.5-kg/m) rail. Samples tested in the laboratory ranged from 109 to 125 ksi (750 to 860 N/mm 2 ) in yield strength. The chromium-molybdenum rails also exhibited excellent fracture toughness and fatigue properties. Sections of the rail were joined by both flash-butt welding and thermite welding. The hardness peaks produced in the flash-butt welds could be reduced by applying either a postweld current or an induction heating cycle. The high-strength chromium-molybdenum rails have been in service for over eight months in curved sections of an ore railway that carries over 55 million gross long tons per year. 7 tables, 18 figs

The relationship between compressive strength and flexural strength of pavement geopolymer grouting material

Science.gov (United States)

Zhang, L.; Han, X. X.; Ge, J.; Wang, C. H.

2018-01-01

To determine the relationship between compressive strength and flexural strength of pavement geopolymer grouting material, 20 groups of geopolymer grouting materials were prepared, the compressive strength and flexural strength were determined by mechanical properties test. On the basis of excluding the abnormal values through boxplot, the results show that, the compressive strength test results were normal, but there were two mild outliers in 7days flexural strength test. The compressive strength and flexural strength were linearly fitted by SPSS, six regression models were obtained by linear fitting of compressive strength and flexural strength. The linear relationship between compressive strength and flexural strength can be better expressed by the cubic curve model, and the correlation coefficient was 0.842.

Near-ideal strength in metal nanotubes revealed by atomistic simulations

Energy Technology Data Exchange (ETDEWEB)

Sun, Mingfei; Xiao, Fei [Department of Materials Science, Fudan University, 220 Handan Road, Shanghai 200433 (China); Deng, Chuang, E-mail: dengc@ad.umanitoba.ca [Department of Mechanical and Manufacturing Engineering, The University of Manitoba, 15Gillson Street, Winnipeg, Manitoba R3T 5V6 (Canada)

2013-12-02

Here we report extraordinary mechanical properties revealed by atomistic simulations in metal nanotubes with hollow interior that have been long overlooked. Particularly, the yield strength in [1 1 1] Au nanotubes is found to be up to 60% higher than the corresponding solid Au nanowire, which approaches the theoretical ideal strength in Au. Furthermore, a remarkable transition from sharp to smooth yielding is observed in Au nanotubes with decreasing wall thickness. The ultrahigh tensile strength in [1 1 1] Au nanotube might originate from the repulsive image force exerted by the interior surface against dislocation nucleation from the outer surface.

An alternative approach for modeling strength differential effect in sheet metals with symmetric yield functions

Science.gov (United States)

Kurukuri, Srihari; Worswick, Michael J.

2013-12-01

An alternative approach is proposed to utilize symmetric yield functions for modeling the tension-compression asymmetry commonly observed in hcp materials. In this work, the strength differential (SD) effect is modeled by choosing separate symmetric plane stress yield functions (for example, Barlat Yld 2000-2d) for the tension i.e., in the first quadrant of principal stress space, and compression i.e., third quadrant of principal stress space. In the second and fourth quadrants, the yield locus is constructed by adopting interpolating functions between uniaxial tensile and compressive stress states. In this work, different interpolating functions are chosen and the predictive capability of each approach is discussed. The main advantage of this proposed approach is that the yield locus parameters are deterministic and relatively easy to identify when compared to the Cazacu family of yield functions commonly used for modeling SD effect observed in hcp materials.

Bond strength of masonry

NARCIS (Netherlands)

Pluijm, van der R.; Vermeltfoort, A.Th.

1992-01-01

Bond strength is not a well defined property of masonry. Normally three types of bond strength can be distinguished: - tensile bond strength, - shear (and torsional) bond strength, - flexural bond strength. In this contribution the behaviour and strength of masonry in deformation controlled uniaxial

Strength and life under creeping

International Nuclear Information System (INIS)

Pospishil, B.

1982-01-01

Certain examples of the application of the Lepin modified creep model, which are of interest from technical viewpoint, are presented. Mathematical solution of the dependence of strength limit at elevated temperatures on creep characteristics is obtained. Tensile test at elevated temperatures is a particular case of creep or relaxation and both strength limit and conventional yield strength at elevated temperatures are completely determined by parameters of state equations during creep. The equation of fracture summing during creep is confirmed not only by the experiment data when stresses change sporadically, but also by good reflection of durability curve using the system of equations. The system presented on the basis of parameters of the equations obtained on any part of durability curve, permits to forecast the following parameters of creep: strain, strain rate, life time, strain in the process of fracture. Tensile test at elevated temperature is advisable as an addition when determining creep curves (time-strain curves) [ru

Reference Values of Grip Strength, Prevalence of Low Grip Strength, and Factors Affecting Grip Strength Values in Chinese Adults.

Science.gov (United States)

Yu, Ruby; Ong, Sherlin; Cheung, Osbert; Leung, Jason; Woo, Jean

2017-06-01

The objectives of this study were to update the reference values of grip strength, to estimate the prevalence of low grip strength, and to examine the impact of different aspects of measurement protocol on grip strength values in Chinese adults. A cross-sectional survey of Chinese men (n = 714) and women (n = 4014) aged 18-102 years was undertaken in different community settings in Hong Kong. Grip strength was measured with a digital dynamometer (TKK 5401 Grip-D; Takei, Niigata, Japan). Low grip strength was defined as grip strength 2 standard deviations or more below the mean for young adults. The effects of measurement protocol on grip strength values were examined in a subsample of 45 men and women with repeated measures of grip strength taken with a hydraulic dynamometer (Baseline; Fabrication Enterprises Inc, Irvington, NY), using pair t-tests, intraclass correlation coefficient, and Bland and Altman plots. Grip strength was greater among men than among women (P values than the Baseline hydraulic dynamometer (P values were also observed when the measurement was performed with the elbow extended in a standing position, compared with that with the elbow flexed at 90° in a sitting position, using the same dynamometer (P values of grip strength and estimated the prevalence of low grip strength among Chinese adults spanning a wide age range. These findings might be useful for risk estimation and evaluation of interventions. However, grip strength measurements should be interpreted with caution, as grip strength values can be affected by type of dynamometer used, assessment posture, and elbow position. Copyright © 2017 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

Prediction of failure strain and burst pressure in high yield-to-tensile strength ratio linepipe

International Nuclear Information System (INIS)

Law, M.; Bowie, G.

2007-01-01

Failure pressures and strains were predicted for a number of burst tests as part of a project to explore failure strain in high yield-to-tensile strength ratio linepipe. Twenty-three methods for predicting the burst pressure and six methods of predicting the failure strain are compared with test results. Several methods were identified which gave accurate and reliable estimates of burst pressure. No method of accurately predicting the failure strain was found, though the best was noted

Prediction of failure strain and burst pressure in high yield-to-tensile strength ratio linepipe

Energy Technology Data Exchange (ETDEWEB)

Law, M. [Institute of Materials and Engineering Science, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW (Australia)]. E-mail: mlx@ansto.gov.au; Bowie, G. [BlueScope Steel Ltd., Level 11, 120 Collins St, Melbourne, Victoria 3000 (Australia)

2007-08-15

Failure pressures and strains were predicted for a number of burst tests as part of a project to explore failure strain in high yield-to-tensile strength ratio linepipe. Twenty-three methods for predicting the burst pressure and six methods of predicting the failure strain are compared with test results. Several methods were identified which gave accurate and reliable estimates of burst pressure. No method of accurately predicting the failure strain was found, though the best was noted.

Development of K-Basin High-Strength Homogeneous Sludge Simulants and Correlations Between Unconfined Compressive Strength and Shear Strength

Energy Technology Data Exchange (ETDEWEB)

Onishi, Yasuo; Baer, Ellen BK; Chun, Jaehun; Yokuda, Satoru T.; Schmidt, Andrew J.; Sande, Susan; Buchmiller, William C.

2011-02-20

K-Basin sludge will be stored in the Sludge Transport and Storage Containers (STSCs) at an interim storage location on Central Plateau before being treated and packaged for disposal. During the storage period, sludge in the STSCs may consolidate/agglomerate, potentially resulting in high-shear-strength material. The Sludge Treatment Project (STP) plans to use water jets to retrieve K-Basin sludge after the interim storage. STP has identified shear strength to be a key parameter that should be bounded to verify the operability and performance of sludge retrieval systems. Determining the range of sludge shear strength is important to gain high confidence that a water-jet retrieval system can mobilize stored K-Basin sludge from the STSCs. The shear strength measurements will provide a basis for bounding sludge properties for mobilization and erosion. Thus, it is also important to develop potential simulants to investigate these phenomena. Long-term sludge storage tests conducted by Pacific Northwest National Laboratory (PNNL) show that high-uranium-content K-Basin sludge can self-cement and form a strong sludge with a bulk shear strength of up to 65 kPa. Some of this sludge has 'paste' and 'chunks' with shear strengths of approximately 3-5 kPa and 380-770 kPa, respectively. High-uranium-content sludge samples subjected to hydrothermal testing (e.g., 185 C, 10 hours) have been observed to form agglomerates with a shear strength up to 170 kPa. These high values were estimated by measured unconfined compressive strength (UCS) obtained with a pocket penetrometer. Due to its ease of use, it is anticipated that a pocket penetrometer will be used to acquire additional shear strength data from archived K-Basin sludge samples stored at the PNNL Radiochemical Processing Laboratory (RPL) hot cells. It is uncertain whether the pocket penetrometer provides accurate shear strength measurements of the material. To assess the bounding material strength and

Estimation and comparison of tensile bond strengths at resin-dentin ...

African Journals Online (AJOL)

Nigerian Dental Journal ... Result: Etch-and-rinse adhesive Adper Single Bond 2 Total Etch® yielded high bond strength ... The self etch systems though convenient to use, do not match the bond strengths of conventional total etch systems.

Effect of precipitate on yield strength of ferritic/martensitic steel exposed to 650 .deg. C liquid sodium

Energy Technology Data Exchange (ETDEWEB)

Kim, Tae Yong; Lee, Jeonghyeon; Kim, Ji Hyun [UNIST, Ulsan (Korea, Republic of); Shin, Sang Hun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

Ferritic/martensitic steels(FMS) which are used as one of cladding and structure materials in UCFR, have high creep strength at 600~650°C, low expansion coefficient, and dimensional stability with irradiation-induced void swelling in circumstance of fast neutrons compared to austenitic stainless steel. However, as exposed to high temperature liquid sodium during the design life time (30 to 60 years), the surface of FMS experienced Cr-depletion and decarburization by dissolution of components into sodium and formed oxidations by reacting with sodium. This changes chemical compositions of inter-surface and effects on behavior of precipitations. This change can cause a degradation of mechanical strength of structure material of UCFR. The research about FMS on effects of long term exposure in liquid sodium at 650 °C involve analysis of yield strength by change of microstructure, solid solution hardening and precipitation hardening. It shows how this three parts occupy total yield strength respectively and change over time. In a specific procedure, the microstructure and the surface phenomenon of FMS (Gr. 92) that are exposed to liquid sodium at 650°C, 20 ppm oxygen and are aged in high pure Argon gas environment to express bulk have been investigated by using scanning electron microscope (SEM) and transmission electron microscope (TEM). When specimens were exposed to 650 °C liquid sodium for 1583, 3095 hours and Ar-gas 1601, 2973 hours, mechanical properties of materials were analyzed quantitatively. After experiment, NaCrO{sub 2} oxidation was formed on the surface of Gr.92 at sodium environment. Also, change of microstructure, dissolution of elements, and nucleation and growth of precipitation was raised. During exposed to high temperature at sodium or Ar-gas, annealed lath structure as well as coarsening of tempered martensite structure affects reduction of mechanical properties. And dissolution of elements results in reduction of solid solution hardening. This

Strength of 10CR-N martensitic steels

International Nuclear Information System (INIS)

Bahrami, F.; Hendry, A.

1993-01-01

10Cr stainless steel has been employed to examine the effect of nitrogen on microstructure and strength. Applying Solid state gaseous nitrogenising treatments a whole range of nitrogen martensite structures containing up to 0.45 wt% were obtained. It was found that a linear relationship exists between strength and nitrogen content in precipitate free martensitic structures. Yield strength increased from 705 to 1295 MPa for nitrogen free base material and alloys with 0.35 wt%N respectively. Pronounce secondary hardening was observed at a tempering temperature of 500 C. A linear relationship was also observed between the lattice parameter and nitrogen concentration in these alloys. A model for mechanical behaviour is presented. (orig.)

On the shear strength of tungsten nano-structures with embedded helium

International Nuclear Information System (INIS)

Smirnov, R.D.; Krasheninnikov, S.I.

2013-01-01

Modification of plastic properties of tungsten nano-structures under shear stress load due to embedded helium atoms is studied using molecular dynamics modelling. The modelling demonstrates that the yield strength of tungsten nano-structures reduces significantly with increasing embedded helium concentration. At high helium concentrations (>10 at%), the yield strength decreases to values characteristic to the pressure in helium nano-bubbles, which are formed in tungsten under such conditions and thought to be responsible for the formation of nano-fuzz on tungsten surfaces irradiated with helium plasma. It is also shown that tungsten plastic flow strongly facilitates coagulation of helium clusters to larger bubbles. The temperature dependencies of the yield strength are obtained. (letter)

Strengths-based Learning

DEFF Research Database (Denmark)

Ledertoug, Mette Marie

-being. The Ph.D.-project in Strength-based learning took place in a Danish school with 750 pupils age 6-16 and a similar school was functioning as a control group. The presentation will focus on both the aware-explore-apply processes and the practical implications for the schools involved, and on measurable......Strength-based learning - Children͛s Character Strengths as Means to their Learning Potential͛ is a Ph.D.-project aiming to create a strength-based mindset in school settings and at the same time introducing strength-based interventions as specific tools to improve both learning and well...

Apparent target strength in long-rod penetration

Energy Technology Data Exchange (ETDEWEB)

Godwin, R.P.; Chapyak, E.J. [Los Alamos National Lab., NM (United States). Applied Theoretical and Computational Physics Div.

1996-03-01

The authors investigate the apparent enhancement of target strength in the steady-state Tate model of long-rod penetration. They show that computing the effective area over which the target behaves as a fluid provides an explanation of the effective 1-D target strength measured empirically. Expressing the effective target strength as R{sub t} = a {times} Y{sub t}, they postulate that a = A{sub e}/A{sub p}, where Y{sub t} is the nominal strength; A{sub e} is the effective target fluid cross-sectional area and A{sub p} the projectile cross-sectional area. For the case of a rod and projectile of the same material, they use the Tate model together with the jet model of Birkhoff et al. to show a {approx} 4 is likely. Simultaneously satisfying Newton`s Second Law and the Tate model yields a very general derivation of a = 4. By explicitly including strength terms in both the Tate equation and Newton`s Second Law, an even more general a = f(v,{rho}{sub p},{rho}{sub t},Y{sub p},Y{sub t}) can be derived.

Influence of silica fume on the strength of high strength concrete

International Nuclear Information System (INIS)

Akram, T.; Memon, S.A.; Khan, S.A.

2007-01-01

HSC (High Strength Concrete) does not become evident by a sudden change in the behavior of 'ordinary strength' concrete. There is a gradual effect that becomes more noticeable when the strength level exceeds about 40-45 MPa. There cannot be a precise level of strength which defines this change in effect. The effects are on strength and workability, requiring us to take into account in our mix proportioning, the ramifications of fineness of cement on workability and of type of aggregate and aggregate/cement ratio on strength. In fact, the selection of materials becomes more critical as the concrete strength increases and that if very high strength is required (100 MPa and higher), relatively few materials may be suitable. An experimental investigation is carried out to evaluate the feasibility of producing HSC using locally available materials and to study the influence of silica fume on the strength of HSC. The main variables in this research is amount of silica fume. The parameters that are kept constant are the amount of cement equal to 580 kg/m3, dosage of HRWRA (High Range Water Reducing Admictures) equal to 4 % by weight of cementitious materials and the ratio of fine aggregate to coarse aggregate (1:2.3). Test results revealed that it is feasible to produce HSC using locally available materials. The optimum percentage of silica fume was found to be 15 % by weight of cement. (author)

Grain size effect on yield strength of titanium alloy implanted with aluminum ions

Energy Technology Data Exchange (ETDEWEB)

Popova, Natalya, E-mail: natalya-popova-44@mail.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk (Russian Federation); Nikonenko, Elena, E-mail: vilatomsk@mail.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30, Lenin Str., 634050, Tomsk (Russian Federation); Yurev, Ivan, E-mail: yiywork@mail.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Kalashnikov, Mark, E-mail: kmp1980@mail.ru [Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk (Russian Federation); Kurzina, Irina, E-mail: kurzina99@mail.ru [National Research Tomsk State University, 36, Lenin Str., 634050, Tomsk (Russian Federation)

2016-01-15

The paper presents a transmission electron microscopy (TEM) study of the microstructure and phase state of commercially pure titanium VT1-0 implanted by aluminum ions. This study has been carried out before and after the ion implantation for different grain size, i.e. 0.3 µm (ultra-fine grain condition), 1.5 µm (fine grain condition), and 17 µm (polycrystalline condition). This paper presents details of calculations and analysis of strength components of the yield stress. It is shown that the ion implantation results in a considerable hardening of the entire thickness of the implanted layer in the both grain types. The grain size has, however, a different effect on the yield stress. So, both before and after the ion implantation, the increase of the grain size leads to the decrease of the alloy hardening. Thus, hardening in ultra-fine and fine grain alloys increased by four times, while in polycrystalline alloy it increased by over six times.

Association Between Maximal Bench Press Strength and Isometric Handgrip Strength Among Breast Cancer Survivors.

Science.gov (United States)

Rogers, Benjamin H; Brown, Justin C; Gater, David R; Schmitz, Kathryn H

2017-02-01

To characterize the relationship between 1-repetition maximum (1-RM) bench press strength and isometric handgrip strength among breast cancer survivors. Cross-sectional study. Laboratory. Community-dwelling breast cancer survivors (N=295). Not applicable. 1-RM bench press strength was measured with a barbell and exercise bench. Isometric handgrip strength was measured using an isometric dynamometer, with 3 maximal contractions of the left and right hands. All measures were conducted by staff with training in clinical exercise testing. Among 295 breast cancer survivors, 1-RM bench press strength was 18.2±6.1kg (range, 2.2-43.0kg), and isometric handgrip strength was 23.5±5.8kg (range, 9.0-43.0kg). The strongest correlate of 1-RM bench press strength was the average isometric handgrip strength of both hands (r=.399; Pisometric handgrip strength of both hands overestimated 1-RM bench press strength by 4.7kg (95% limits of agreement, -8.2 to 17.6kg). In a multivariable linear regression model, the average isometric handgrip strength of both hands (β=.31; Pstrength (R 2 =.23). Isometric handgrip strength is a poor surrogate for 1-RM bench press strength among breast cancer survivors. 1-RM bench press strength and isometric handgrip strength quantify distinct components of muscular strength. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Flow Strength of Shocked Aluminum in the Solid-Liquid Mixed Phase Region

Science.gov (United States)

Reinhart, William

2011-06-01

Shock waves have been used to determine material properties under high shock stresses and very-high loading rates. The determination of mechanical properties such as compressive strength under shock compression has proven to be difficult and estimates of strength have been limited to approximately 100 GPa or less in aluminum. The term ``strength'' has been used in different ways. For a Von-Mises solid, the yield strength is equal to twice the shear strength of the material and represents the maximum shear stress that can be supported before yield. Many of these concepts have been applied to materials that undergo high strain-rate dynamic deformation, as in uni-axial strain shock experiments. In shock experiments, it has been observed that the shear stress in the shocked state is not equal to the shear strength, as evidenced by elastic recompressions in reshock experiments. This has led to an assumption that there is a yield surface with maximum (loading)and minimum (unloading), shear strength yet the actual shear stress lies somewhere between these values. This work provides the first simultaneous measurements of unloading velocity and flow strength for transition of solid aluminum to the liquid phase. The investigation describes the flow strength observed in 1100 (pure), 6061-T6, and 2024 aluminum in the solid-liquid mixed phase region. Reloading and unloading techniques were utilized to provide independent data on the two unknowns (τc and τo) , so that the actual critical shear strength and the shear stress at the shock state could be estimated. Three different observations indicate a change in material response for stresses of 100 to 160 GPa; 1) release wave speed (reloading where applicable) measurements, 2) yield strength measurements, and 3) estimates of Poisson's ratio, all of which provide information on the melt process including internal consistency and/or non-equilibrium and rate-dependent melt behavior. The study investigates the strength properties

Effect of wear on the burst strength of l-80 steel casing

International Nuclear Information System (INIS)

Irawan, S; Bharadwaj, A M; Temesgen, B; Karuppanan, S; Abdullah, M Z B

2015-01-01

Casing wear has recently become one of the areas of research interest in the oil and gas industry especially in extended reach well drilling. The burst strength of a worn out casing is one of the significantly affected mechanical properties and is yet an area where less research is done The most commonly used equations to calculate the resulting burst strength after wear are Barlow, the initial yield burst, the full yield burst and the rupture burst equations. The objective of this study was to estimate casing burst strength after wear through Finite Element Analysis (FEA). It included calculation and comparison of the different theoretical bursts pressures with the simulation results along with effect of different wear shapes on L-80 casing material. The von Misses stress was used in the estimation of the burst pressure. The result obtained shows that the casing burst strength decreases as the wear percentage increases. Moreover, the burst strength value of the casing obtained from the FEA has a higher value compared to the theoretical burst strength values. Casing with crescent shaped wear give the highest burst strength value when simulated under nonlinear analysis. (paper)

Chain Ends and the Ultimate Tensile Strength of Polyethylene Fibers

Science.gov (United States)

O'Connor, Thomas C.; Robbins, Mark O.

Determining the tensile yield mechanisms of oriented polymer fibers remains a challenging problem in polymer mechanics. By maximizing the alignment and crystallinity of polyethylene (PE) fibers, tensile strengths σ ~ 6 - 7 GPa have been achieved. While impressive, first-principal calculations predict carbon backbone bonds would allow strengths four times higher (σ ~ 20 GPa) before breaking. The reduction in strength is caused by crystal defects like chain ends, which allow fibers to yield by chain slip in addition to bond breaking. We use large scale molecular dynamics (MD) simulations to determine the tensile yield mechanism of orthorhombic PE crystals with finite chains spanning 102 -104 carbons in length. The yield stress σy saturates for long chains at ~ 6 . 3 GPa, agreeing well with experiments. Chains do not break but always yield by slip, after nucleation of 1D dislocations at chain ends. Dislocations are accurately described by a Frenkel-Kontorova model, parametrized by the mechanical properties of an ideal crystal. We compute a dislocation core size ξ = 25 . 24 Å and determine the high and low strain rate limits of σy. Our results suggest characterizing such 1D dislocations is an efficient method for predicting fiber strength. This research was performed within the Center for Materials in Extreme Dynamic Environments (CMEDE) under the Hopkins Extreme Materials Institute at Johns Hopkins University. Financial support was provided by Grant W911NF-12-2-0022.

Compressive and flexural strength of high strength phase change mortar

Science.gov (United States)

Qiao, Qingyao; Fang, Changle

2018-04-01

High-strength cement produces a lot of hydration heat when hydrated, it will usually lead to thermal cracks. Phase change materials (PCM) are very potential thermal storage materials. Utilize PCM can help reduce the hydration heat. Research shows that apply suitable amount of PCM has a significant effect on improving the compressive strength of cement mortar, and can also improve the flexural strength to some extent.

INFLUENCE OF STRENGTH TRAINING PROGRAM ON ISOMETRIC MUSCLE STRENGTH IN YOUNG ATHLETES

Directory of Open Access Journals (Sweden)

Dragan Radovanovic

2007-10-01

Full Text Available Strength training, or resistance training, is a form of physical conditioning used to increase the ability to resist force. Since muscular strength is required for success in many sports, it is logical to assume that stronger and more powerful young athletes will achieve better results. The aim of the study was to examine the effects of strength training on young athletes. An eight-week strength training program for developing muscle strength was performed in this study. Training protocol was designed specifically for young adolescent’s athletes. The program consisted of exercises for lower and upper body, abdominal and lower back muscles. The programs did not involve the maximal (1-3 repetitions maximum and other very hard intensity exercises that may had negative effect on young athletes. The results showed that strength training program had positive effects on maximal isometric muscle force (Fmax and motor skill. The increase presents the combined influence of strength training and growth.

Give Me Strength.

Institute of Scientific and Technical Information of China (English)

维拉

1996-01-01

Mort had an absolutely terrible day at the office.Everythingthat could go wrong did go wrong.As he walked home he could beheard muttering strange words to himself:“Oh,give me strength,give me strength.”Mort isn’t asking for the kind of strength thatbuilds strong muscles:he’s asking for the courage or ability to

Yield strength, shear stress and toughness of YBCO samples textured by Bridgman technique

International Nuclear Information System (INIS)

Roa, J J; Capdevila, X G; Martinez, M; Segarra, M; Jimenez-Pique, E

2008-01-01

Mechanical properties of the orthorhombic phase of YBa 2 Cu 3 O 7-δ (Y-123) at room temperature have been investigated at different applied loads using nanoindentation technique. The study was carried out for several monodomains on the (001) planes for textured Bridgman samples with dispersed Y 2 BaCuO 5 (Y-211) particles as pinning centers. The yield strength (σ ys ), shear stress (τ m ) and toughness (K IC ) of Y123/Y211composite was determined at different applied loads. First and second mechanical properties have been calculated though the Hertz equations and the last one with Lawn et al. equations. Finally, the ultra-low imprints obtained by nanoindentation have been correlated with parameters obtained by Field Emission Scanning Electron Microscope (FE-SEM)

The Association between Maximal Bench Press Strength and Isometric Handgrip Strength among Breast Cancer Survivors

Science.gov (United States)

Rogers, Benjamin H.; Brown, Justin C.; Gater, David R.; Schmitz, Kathryn H.

2016-01-01

Objective One-repetition maximum (1-RM) bench press strength is considered the gold standard to quantify upper-body muscular strength. Isometric handgrip strength is frequently used as a surrogate for 1-RM bench press strength among breast cancer (BrCa) survivors. The relationship between 1-RM bench press strength and isometric handgrip strength, however, has not been characterized among BrCa survivors. Design Cross-sectional study. Setting Laboratory. Participants Community-dwelling BrCa survivors. Interventions Not applicable. Main Outcome Measure 1-RM bench press strength was measured with a barbell and exercise bench. Isometric handgrip strength was measured using an isometric dynamometer with three maximal contractions of left and right hands. All measures were conducted by staff with training in clinical exercise testing. Results Among 295 BrCa survivors, 1-RM bench press strength was 18.2±6.1 kg (range: 2.2-43.0) and isometric handgrip strength was 23.5±5.8 kg (range: 9.0-43.0). The strongest correlate of 1-RM bench press strength was the average isometric handgrip strength of both hands (r=0.399; Pisometric handgrip strength of both hands overestimated 1-RM bench press strength by 4.7 kg (95% limits of agreement: −8.2 to 17.6). In a multivariable linear regression model, the average isometric handgrip strength of both hands (β=0.31; Pstrength (R2=0.23). Conclusions Isometric handgrip strength is a poor surrogate for 1-RM bench press strength among BrCa survivors. 1-RM bench press and isometric handgrip strength quantify distinct components of muscular strength. PMID:27543047

Reactive Strength Index: A Poor Indicator of Reactive Strength?

Science.gov (United States)

Healy, Robin; Kenny, Ian; Harrison, Drew

2017-11-28

The primary aim was to assess the relationships between reactive strength measures and associated kinematic and kinetic performance variables achieved during drop jumps. A secondary aim was to highlight issues with the use of reactive strength measures as performance indicators. Twenty eight national and international level sprinters, consisting of fourteen men and women, participated in this cross-sectional analysis. Athletes performed drop jumps from a 0.3 m box onto a force platform with dependent variables contact time (CT), landing time (TLand), push-off time (TPush), flight time (FT), jump height (JH), reactive strength index (RSI, calculated as JH / CT), reactive strength ratio (RSR, calculated as FT / CT) and vertical leg spring stiffness (Kvert) recorded. Pearson's correlation test found very high to near perfect relationships between RSI and RSR (r = 0.91 to 0.97), with mixed relationships found between RSI, RSR and the key performance variables, (Men: r = -0.86 to -0.71 between RSI/RSR and CT, r = 0.80 to 0.92 between RSI/RSR and JH; Women: r = -0.85 to -0.56 between RSR and CT, r = 0.71 between RSI and JH). This study demonstrates that the method of assessing reactive strength (RSI versus RSR) may be influenced by the performance strategies adopted i.e. whether an athlete achieves their best reactive strength scores via low CTs, high JHs or a combination. Coaches are advised to limit the variability in performance strategies by implementing upper and / or lower CT thresholds to accurately compare performances between individuals.

Influences of Gd on the microstructure and strength of Mg-4.5Zn alloy

International Nuclear Information System (INIS)

Yang Jie; Xiao Wenlong; Wang Lidong; Wu Yaoming; Wang Limin; Zhang Hongjie

2008-01-01

Microstructure and mechanical properties of peak-aged Mg-4.5Zn-xGd (x 0, 0.5, 1.0 and 1.5 wt.%) alloys have been investigated. The results showed that the grain size of the alloys was refined gradually with increasing Gd. Mg 5 Gd and Mg 3 Gd 2 Zn 3 phases were found in the Gd-containing alloys. The strengths were greatly improved with Gd additions, and the highest strength level was obtained in the Mg-4.5Zn-1.5Gd alloy, in which the ultimate tensile strength and yield strength were 231 MPa and 113 MPa, respectively. Through comparing with the Mg-4.5Zn alloy, the increments of ultimate tensile strength and yield strength were 22 MPa and 56 MPa, respectively. The improved strength was mainly correlated to the grain refining effect, the strengthening effect of the Mg 5 Gd and Mg 3 Gd 2 Zn 3 phases and also the hardening effect of the solutioned Gd atoms

Increasing Lean Mass and Strength: A Comparison of High Frequency Strength Training to Lower Frequency Strength Training.

Science.gov (United States)

Thomas, Michael H; Burns, Steve P

The purpose of this study was to determine the effect strength training frequency has on improvements in lean mass and strength. Participants were 7 women and 12 men, age ( χ̄ = 34.64 years ± 6.91 years), with strength training experience, training age ( χ̄ = 51.16 months ± 39.02 months). Participants were assigned to one of two groups to equal baseline group demographics. High frequency training group (HFT) trained each muscle group as the agonist, 3 times per week, exercising with 3 sets per muscle group per session (3 total body workouts). Low frequency training group (LFT) trained each muscle group as the agonist one time per week, completing all 9 sets during that one workout. LFT consisted of a routine split over three days: 1) pectoralis, deltoids, and triceps; 2) upper back and biceps; 3) quadriceps, hamstrings, calves, and abdominals. Following eight weeks of training, HFT increased lean mass by 1.06 kg ± 1.78 kg, (1.9%), and LFT increased lean mass by .99 kg ± 1.31 kg, (2.0%). HFT strength improvements on the chest press was 9.07 kg ± 6.33 kg, (11%), and hack squat 20.16 kg ± 11.59 kg, (21%). LFT strength improvements on chest press was 5.80kg ± 4.26 kg, (7.0%), and hack squat 21.83 kg ± 11.17 kg, (24 %). No mean differences between groups were significant. These results suggest that HFT and LFT of equal set totals result in similar improvements in lean mass and strength, following 8 weeks of strength training.

Axial Compressive Strength of Foamcrete with Different Profiles and Dimensions

Directory of Open Access Journals (Sweden)

Othuman Mydin M.A.

2014-01-01

Full Text Available Lightweight foamcrete is a versatile material; primarily consist of a cement based mortar mixed with at least 20% volume of air. High flow ability, lower self-weight, minimal requirement of aggregate, controlled low strength and good thermal insulation properties are a few characteristics of foamcrete. Its dry densities, typically, is below 1600kg/m3 with compressive strengths maximum of 15MPa. The ASTM standard provision specifies a correction factor for concrete strengths of between 14 and 42MPa to compensate for the reduced strength when the aspect height-to-diameter ratio of specimen is less than 2.0, while the CEB-FIP provision specifically mentions the ratio of 150 x 300mm cylinder strength to 150 mm cube strength. However, both provisions requirements do not specifically clarify the applicability and/or modification of the correction factors for the compressive strength of foamcrete. This proposed laboratory work is intended to study the effect of different dimensions and profiles on the axial compressive strength of concrete. Specimens of various dimensions and profiles are cast with square and circular cross-sections i.e., cubes, prisms and cylinders, and to investigate their behavior in compression strength at 7 and 28 days. Hypothetically, compressive strength will decrease with the increase of concrete specimen dimension and concrete specimen with cube profile would yield comparable compressive strength to cylinder (100 x 100 x 100mm cube to 100dia x 200mm cylinder.

Enhancement of strength properties of hot rolled 10KHSND steel

International Nuclear Information System (INIS)

Nasibov, A.G.; Popova, L.V.; Pikulin, S.A.; Globa, N.I.

1989-01-01

To find out the reasons of low hot rolling yield for 10KhSND steel sheets in mechanical properties, titanium effect in the range of 0.008-0.03% concentrations is studied. It is established that the titanium content in a solid solution is conserved within 0.003-0.005%, the rest of titanium is bound to carbonitrides Ti(C, N). It is shown that alloys with 0.025-0.03% titanium content possess the increased values of ultimate and yield strength the necessary level of impact strength and good wealdability. The good steel yield, when the titanium content is sustained at the given level, increases from 40 to 85%

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

Science.gov (United States)

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

2016-02-01

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

Long-term outcome of muscle strength in ulnar and median nerve injury: Comparing manual muscle strength testing, grip and pinch strength dynamometers and a new intrinsic muscle strength dynamometer

NARCIS (Netherlands)

A.R. Schreuders (Ton); M.E. Roebroeck (Marij); J.B. Jaquet (Jean); S.E.R. Hovius (Steven); H.J. Stam (Henk)

2004-01-01

textabstractObjective: To compare the outcome of muscle strength with manual muscle strength testing grip and pinch strength measurements and a dynamometer which allows for measurements of the intrinsic muscles of the hand in isolation (the Rotterdam Intrinsic Hand Myometer, RIHM). Methods:

Strength-toughness requirements for thick walled high pressure vessels

International Nuclear Information System (INIS)

Kapp, J.A.

1990-01-01

The strength and toughness requirements of materials for use in high pressure vessels has been the subject of some discussion in the meetings of the Materials Task Group of the Special Working Group High Pressure Vessels. A fracture mechanics analysis has been performed to theoretically establish the required toughness for a high pressure vessel. This paper reports that the analysis performed is based on the validity requirement for plane strain fracture of fracture toughness test specimens. This is that at the fracture event, the crack length, uncracked ligament, and vessel length must each be greater than fifty times the crack tip plastic zone size for brittle fracture to occur. For high pressure piping applications, the limiting physical dimension is the uncracked ligament, as it can be assumed that the other dimensions are always greater than fifty times the crack tip plastic zone. To perform the fracture mechanics analysis several parameters must be known: these include vessel dimensions, material strength, degree of autofrettage, and design pressure. Results of the analysis show, remarkably, that the effects of radius ratio, pressure and degree of autofrettage can be ignored when establishing strength and toughness requirements for code purposes. The only parameters that enter into the calculation are yield strength, toughness and vessel thickness. The final results can easily be represented as a graph of yield strength against toughness on which several curves, one for each vessel thickness, are plotted

Acute Effects of Partial-Body Cryotherapy on Isometric Strength: Maximum Handgrip Strength Evaluation.

Science.gov (United States)

De Nardi, Massimo; Pizzigalli, Luisa; Benis, Roberto; Caffaro, Federica; Micheletti Cremasco, Margherita

2017-12-01

De Nardi, M, Pizzigalli, L, Benis, R, Caffaro, F, and Cremasco, MM. Acute effects of partial-body cryotherapy on isometric strength: maximum handgrip strength evaluation. J Strength Cond Res 31(12): 3497-3502, 2017-The aim of the study was to evaluate the influence of a single partial-body cryotherapy (PBC) session on the maximum handgrip strength (JAMAR Hydraulic Hand dynamometer). Two hundred healthy adults were randomized into a PBC group and a control group (50 men and 50 women in each group). After the initial handgrip strength test (T0), the experimental group performed a 150-second session of PBC (temperature range between -130 and -160° C), whereas the control group stayed in a thermo neutral room (22.0 ± 0.5° C). Immediately after, both groups performed another handgrip strength test (T1). Data underlined that both groups showed an increase in handgrip strength values, especially the experimental group (Control: T0 = 39.48 kg, T1 = 40.01 kg; PBC: T0 = 39.61 kg, T1 = 41.34 kg). The analysis also reported a statistical effect related to gender (F = 491.99, P ≤ 0.05), with women showing lower handgrip strength values compared with men (women = 30.43 kg, men = 52.27 kg). Findings provide the first evidence that a single session of PBC leads to the improvement of muscle strength in healthy people. The results of the study imply that PBC could be performed also before a training session or a sport competition, to increase hand isometric strength.

Traditional versus functional strength training: Effects on muscle strength and power in the elderly

OpenAIRE

Seiler, Hilde Lohne; Torstveit, Monica Klungland; Anderssen, Sigmund A.

2013-01-01

Published versiom of an article in the journal:Journal of Aging and Physical Activity. Also available from Human Kinetics: http://http://journals.humankinetics.com/japa-back-issues/japa-volume-21-issue-1-january/traditional-versus-functional-strength-training-effects-on-muscle-strength-and-power-in-the-elderly The aim was to determine whether strength training with machines vs. functional strength training at 80% of one-repetition maximum improves muscle strength and power among the elderl...

Isometric and swallowing tongue strength in healthy adults.

Science.gov (United States)

Todd, J Tee; Lintzenich, Catherine Rees; Butler, Susan G

2013-10-01

The tongue contributes to a safe swallow. It facilitates bolus control during mastication, maintains a bolus in the oral cavity to prevent premature entry of the bolus into the hypopharynx, and helps generate pressure in the hypopharynx during swallowing. This study examined isometric tongue strength and tongue pressure measured during swallowing in healthy young and older adults. Prospective group design. One hundred twenty-six healthy individuals who were recruited as part of a larger study on swallowing participated in this study. Participants were divided into three age groups: 20 to 40 years, 41 to 60 years, and ≥61 years. A KayPentax Digital Swallowing Workstation with an air-filled bulb array was placed on the tongue of each participant (anterior to posterior). Participants completed three isometric tongue presses and three swallows. Repeated measures analyses of variance revealed a significant main effect of age (P = .01) and gender by tongue bulb location interaction (P = .02) for isometric tongue strength. That is, older adults had lower isometric tongue strength than young adults, and females had a greater difference between anterior and posterior tongue strength than males. Tongue strength during swallowing yielded significantly greater anterior versus posterior tongue pressure. This study comprises one of the largest in terms of number of healthy participants reported to date and confirms previous findings that isometric tongue strength decreases with age. Furthermore, given young and older adults generate similar swallowing pressures, swallowing is a submaximal strength activity, yet older adults have less functional reserve. 4. Copyright © 2013 The American Laryngological, Rhinological, and Otological Society, Inc.

Strength of precast concrete shear joints reinforced with high-strength wire ropes

DEFF Research Database (Denmark)

Joergensen, Henrik B.; Hoang, Linh Cao; Hagsten, Lars German

2017-01-01

This paper concerns the in-plane shear strength of connections between precast concrete wall elements reinforced with looped high-strength wire ropes. The looped wire ropes are pre-installed in so-called ‘wire boxes’ which function as shear keys. Although only a small amount of research...... on the shear strength of such connections can be found in the literature, this type of connection is increasingly being used because wire ropes are much more construction-friendly than traditional U-bars. A rigid plastic upper bound model for the shear strength of wall connections reinforced with looped wire...... ropes that are pre-installed in wire boxes is presented along with test results on the shear strength of connections with double-wire boxes. It is shown that the plastic solution agrees well with both the obtained test results and results from previously conducted tests....

Assessment of long-term creep strength of grade 91 steel

Energy Technology Data Exchange (ETDEWEB)

Kimura, Kazuhiro; Sawada, Kota; Kushima, Hideaki [National Inst. for Materials Science, Tsukuba, Ibaraki (Japan)

2010-07-01

In 2004 and 2005 long-term creep rupture strength of ASME Grade 91 type steels of plate, pipe, forging and tube materials was evaluated in Japan by means of region splitting analysis method in consideration of 50% of 0.2% offset yield stress. According to the evaluated 100,000h creep rupture strength of 94MPa for plate, pipe and forging steels and 92MPa for tube steel at 600 C, allowable tensile stress of the steels regulated in the Interpretation for the Technical Standard for Thermal Power Plant was slightly reduced. New creep rupture data of the steels obtained in the long-term indicate further reduction of long-term creep rupture strength. Not only creep rupture strength, but also creep deformation property of the ASME Grade 91 steel was investigated and need of reevaluation of long-term creep strength of Grade 91 steel was indicated. A refinement of region splitting analysis method for creep rupture like prediction was discussed. (orig.)

Multistep triaxial strength tests: investigating strength parameters and pore pressure effects on Opalinus Clay

International Nuclear Information System (INIS)

Graesle, W.

2010-01-01

Document available in extended abstract form only. The impact of natural variability between rock samples from a single formation is a common problem for the characterisation of THM properties of rocks. Data variation arising from heterogeneity between samples often obscures details of material behaviour. Besides efforts to reduce this statistical noise by careful selection of samples, there are essentially two approaches to overcome this problem: - To generate very large data sets for better statistics. - To avoid the impact of natural variability by yielding an extensive data set from a single sample. The multistep strength test follows the latter approach to characterise the mechanical behaviour of Opalinus Clay from Mont Terri and the possible impact of pore pressure effects. The concept of the multistep strength test comprises three test sections, each focused on the investigation of one mechanical characteristic of Opalinus Clay. Any section is composed of a series of strain controlled load cycles at various levels of confining pressure. 1) The linear elastic limit, i.e. the onset of nonlinearity in the stress-strain-relationship σ dev (ε 1 ) during strain-controlled triaxial loading, is determined in section 1. It defines a lower limit for the onset of damage. Avoiding sample damage is essential during this test section to ensure that all measurements reflect the behaviour of undisturbed material. Therefore, a rather strict and well detectable criterion for the onset of nonlinearity is required to enable a timely termination of any load phase. 2) Section 2 is focused on shear strength. Any load cycle is stopped as soon as peak stress is detected. As progressive damage of the sample is unavoidable during this process, it must be expected that only very few measured peak stresses approximately represent properties of the undamaged material. 3) Test section 3 is a conventional test of residual strength. Tests are carried out on cylindrical samples (100 mm

The effect of Nordic hamstring strength training on muscle architecture, stiffness, and strength.

Science.gov (United States)

Seymore, Kayla D; Domire, Zachary J; DeVita, Paul; Rider, Patrick M; Kulas, Anthony S

2017-05-01

Hamstring strain injury is a frequent and serious injury in competitive and recreational sports. While Nordic hamstring (NH) eccentric strength training is an effective hamstring injury-prevention method, the protective mechanism of this exercise is not understood. Strength training increases muscle strength, but also alters muscle architecture and stiffness; all three factors may be associated with reducing muscle injuries. The purpose of this study was to examine the effects of NH eccentric strength training on hamstring muscle architecture, stiffness, and strength. Twenty healthy participants were randomly assigned to an eccentric training group or control group. Control participants performed static stretching, while experimental participants performed static stretching and NH training for 6 weeks. Pre- and post-intervention measurements included: hamstring muscle architecture and stiffness using ultrasound imaging and elastography, and maximal hamstring strength measured on a dynamometer. The experimental group, but not the control group, increased volume (131.5 vs. 145.2 cm 3 , p hamstring strength. The NH intervention was an effective training method for muscle hypertrophy, but, contrary to common literature findings for other modes of eccentric training, did not increase fascicle length. The data suggest that the mechanism behind NH eccentric strength training mitigating hamstring injury risk could be increasing volume rather than increasing muscle length. Future research is, therefore, warranted to determine if muscle hypertrophy induced by NH training lowers future hamstring strain injury risk.

Lifting strength in two-person teamwork.

Science.gov (United States)

Lee, Tzu-Hsien

2016-01-01

This study examined the effects of lifting range, hand-to-toe distance, and lifting direction on single-person lifting strengths and two-person teamwork lifting strengths. Six healthy males and seven healthy females participated in this study. Two-person teamwork lifting strengths were examined in both strength-matched and strength-unmatched groups. Our results showed that lifting strength significantly decreased with increasing lifting range or hand-to-toe distance. However, lifting strengths were not affected by lifting direction. Teamwork lifting strength did not conform to the law of additivity for both strength-matched and strength-unmatched groups. In general, teamwork lifting strength was dictated by the weaker of the two members, implying that weaker members might be exposed to a higher potential danger in teamwork exertions. To avoid such overexertion in teamwork, members with significantly different strength ability should not be assigned to the same team.

The theoretical tensile strength of fcc crystals predicted from shear strength calculations

International Nuclear Information System (INIS)

Cerny, M; Pokluda, J

2009-01-01

This work presents a simple way of estimating uniaxial tensile strength on the basis of theoretical shear strength calculations, taking into account its dependence on a superimposed normal stress. The presented procedure enables us to avoid complicated and time-consuming analyses of elastic stability of crystals under tensile loading. The atomistic simulations of coupled shear and tensile deformations in cubic crystals are performed using first principles computational code based on pseudo-potentials and the plane wave basis set. Six fcc crystals are subjected to shear deformations in convenient slip systems and a special relaxation procedure controls the stress tensor. The obtained dependence of the ideal shear strength on the normal tensile stress seems to be almost linearly decreasing for all investigated crystals. Taking these results into account, the uniaxial tensile strength values in three crystallographic directions were evaluated by assuming a collapse of the weakest shear system. Calculated strengths for and loading were found to be mostly lower than previously calculated stresses related to tensile instability but rather close to those obtained by means of the shear instability analysis. On the other hand, the strengths for loading almost match the stresses related to tensile instability.

Extended Hall-Petch Relationships for Yield, Cleavage and Intergranular Fracture Strengths of bcc Steel and Its Deformation and Fracture Behaviors

Science.gov (United States)

Heo, N. H.; Heo, Y.-U.; Kwon, S. K.; Kim, N. J.; Kim, S.-J.; Lee, H.-C.

2018-03-01

Extended Hall-Petch relationships for yield ( σy ), cleavage ( σ_{cl} ) and intergranular fracture ( σ_{ig} ) strengths of pure iron have been established through the direct calculation of the proportional constant (k) and the estimation of the friction stress (σ0 ) . The magnitude orders of k and σ0 are generally ky causes the high work hardening rate.

Study on creep of fiber reinforced ultra-high strength concrete based on strength

Science.gov (United States)

Peng, Wenjun; Wang, Tao

2018-04-01

To complement the creep performance of ultra-high strength concrete, the long creep process of fiber reinforced concrete was studied in this paper. The long-term creep process and regularity of ultra-high strength concrete with 0.5% PVA fiber under the same axial compression were analyzed by using concrete strength (C80/C100/C120) as a variable. The results show that the creep coefficient of ultra-high strength concrete decreases with the increase of concrete strength. Compared with ACI209R (92), GL2000 models, it is found that the predicted value of ACI209R (92) are close to the experimental value, and the creep prediction model suitable for this experiment is proposed based on ACI209R (92).

Size effects in olivine control strength in low-temperature plasticity regime

Science.gov (United States)

Kumamoto, K. M.; Thom, C.; Wallis, D.; Hansen, L. N.; Armstrong, D. E. J.; Goldsby, D. L.; Warren, J. M.; Wilkinson, A. J.

2017-12-01

The strength of the lithospheric mantle during deformation by low-temperature plasticity controls a range of geological phenomena, including lithospheric-scale strain localization, the evolution of friction on deep seismogenic faults, and the flexure of tectonic plates. However, constraints on the strength of olivine in this deformation regime are difficult to obtain from conventional rock-deformation experiments, and previous results vary considerably. We demonstrate via nanoindentation that the strength of olivine in the low-temperature plasticity regime is dependent on the length-scale of the test, with experiments on smaller volumes of material exhibiting larger yield stresses. This "size effect" has previously been explained in engineering materials as a result of the role of strain gradients and associated geometrically necessary dislocations in modifying plastic behavior. The Hall-Petch effect, in which a material with a small grain size exhibits a higher strength than one with a large grain size, is thought to arise from the same mechanism. The presence of a size effect resolves discrepancies among previous experimental measurements of olivine, which were either conducted using indentation methods or were conducted on polycrystalline samples with small grain sizes. An analysis of different low-temperature plasticity flow laws extrapolated to room temperature reveals a power-law relationship between length-scale (grain size for polycrystalline deformation and contact radius for indentation tests) and yield strength. This suggests that data from samples with large inherent length scales best represent the plastic strength of the coarse-grained lithospheric mantle. Additionally, the plastic deformation of nanometer- to micrometer-sized asperities on fault surfaces may control the evolution of fault roughness due to their size-dependent strength.

Experimental knee joint pain during strength training and muscle strength gain in healthy subjects

DEFF Research Database (Denmark)

Sørensen, T J; Langberg, Henning; Hodges, P W

2012-01-01

Knee joint pain and reduced quadriceps strength are cardinal symptoms in many knee pathologies. In people with painful knee pathologies, quadriceps exercise reduces pain, improves physical function, and increases muscle strength. A general assumption is that pain compromises muscle function...... and thus may prevent effective rehabilitation. This study evaluated the effects of experimental knee joint pain during quadriceps strength training on muscle strength gain in healthy individuals....

Tensile strength and fatigue strength of 6061 aluminum alloy friction welded joints

Energy Technology Data Exchange (ETDEWEB)

Ochi, H.; Tsujino, R. [Osaka Inst. of Tech., Asahi-ku Osaka (Japan); Sawai, T. [Osaka Sangyo Univ., Daito (Japan); Yamamoto, Y. [Setsunan Univ., Neyagawa (Japan); Ogawa, K. [Osaka Prefecture Univ., Sakai (Japan); Suga, Y. [Keio Univ., Kohoku-ku, Yokohama (Japan)

2002-07-01

Friction welding of 6061 aluminum alloy was carried out in order to examine the relationship between deformation heat input in the upset stage and joint performance. The joint performance was evaluated by tensile testing and fatigue testing. Stabilized tensile strength was obtained when the deformation heat input in the upset stage exceeded 200 J/s. Weld condition at the weld interface and the width of softened area affected fatigue strength more than tensile strength. That is, when the weld condition at the weld interface is good and the softened area is wide, fatigue strength increases. On the other hand, when the weld condition at the weld interface is good and the softened area is narrow, and when the weld condition at the weld interface is somewhat poor in spite of the wide softened area, fatigue strength decreases. The fatigue limit obtained by the fatigue testing revealed that, when the deformation heat input in the upset stage exceeded a certain value, sound joints could be produced. (orig.)

Study of strength properties of semi-finished products from economically alloyed high-strength aluminium-scandium alloys for application in automobile transport and shipbuilding

Science.gov (United States)

Baranov, Vladimir; Sidelnikov, Sergey; Zenkin, Evgeny; Frolov, Viktor; Voroshilov, Denis; Yakivyuk, Olga; Konstantinov, Igor; Sokolov, Ruslan; Belokonova, Irina

2018-04-01

The results of a study on the strength of rolled products from aluminium alloys doped with scandium under various processing conditions of hot and cold rolling are presented. The regularities of metal flow and the level of strength of deformed semi-finished products from aluminum-scandium alloys are established, depending on the total degree of deformation and the various modes of single reduction during rolling. It is shown that when using one heating of a cast billet to obtain high-quality semi-finished products, the temperature during the rolling process should not be lower than 350-370°, and the total degree of deformation does not exceed 50-60%. It was found that the semi-finished products from alloys with a content of scandium in the range 0.11-0.12% in the deformed state had elevated values of ultimate tensile strength and yield strength of the metal, which allows them to be recommended for industrial production of sheet metal products.

Strength Gain Properties up to five-year age of high-strength mass concrete

International Nuclear Information System (INIS)

Mitarai, Y.; Shigenobu, M.; Hiramine, T.; Inoue, K.; Nakane, S.; Ohike, T.

1991-01-01

Genkai No.3 plant of Kyushu Electric Power Co., Inc. presently under construction is a PWR type nuclear power plant with 1180 MW power output, and a prestressed concrete containment vessel (PCCV) was adopted for the reactor. The concrete used for the construction of the PCCV is the mass concrete with the wall thickness of 1.3 m in the general parts of the cylinder, and about 2 m at buttresses. It is the high strength concrete of the specified strength 420 kgf/cm 2 . As the preliminary study for the construction using such high strength mass concrete, the examination was carried out on the strength gain property of structural concrete using full scale simulated members. The various problems in the quality control were contemplated based on the results of the examination, and were reflected to actual construction, designating 13 weeks as the age for strength control, in order to build the concrete structures with high reliability. In this report, the outline of the study on the strength gain up to 5 year age carried out in the preliminary study is discussed. The experimental method, the method of evaluating structural strength, the mixing proportion of concrete and the results are reported. (K.I.)

Fatigue in Welded High-Strength Steel Plate Elements under Stochastic Loading

DEFF Research Database (Denmark)

Agerskov, Henning; Petersen, R.I.; Martinez, L. Lopez

1999-01-01

The present project is a part of an investigation on fatigue in offshore structures in high-strength steel. The fatigue life of plate elements with welded attachments is studied. The material used has a yield stress of ~ 810-840 MPa, and high weldability and toughness properties. Fatigue test...... series with constant amplitude loading and with various types of stochastic loading have been carried through on test specimens in high-strength steel, and - for a comparison - on test specimens in conventional offshore structural steel with a yield stress of ~ 400-410 MPa.A comparison between constant...... amplitude and variable amplitude fatigue test results shows shorter fatigue lives in variable amplitude loading than should be expected from the linear fatigue damage accumulation formula. Furthermore, in general longer fatigue lives were obtained for the test specimens in high-strength steel than those...

Metallurgical/Alloy Optimization of High Strength and Wear Resistant Structural Quench and Tempered Steels

Science.gov (United States)

Stalheim, Douglas G.; Peimao, Fu; Linhao, Gu; Yongqing, Zhang

Structural steels with yield strength requirements greater or equal to 690 MPa can be produced through controlled recrystallization hot rolling coupled with precipitation strengthening or purposeful heat treatment through quench and tempering (Q&T). High strength structural steel and wear/abrasion resistant requirements greater or equal to 360 Brinell hardness (BHN) are produced by the development of microstructures of tempered lower bainite and/or martensite through the Q&T process. While these Q&T microstructures can produce very high strengths and hardness levels making them ideal for 690 MPa plus yield strength or wear/abrasion resistant applications, they lack toughness/ductility and hence are very brittle and prone to cracking. While tempering the microstructures helps in improving the toughness/ductility and reducing the brittleness, strength and hardness can be sacrificed. In addition, these steels typically consist of alloy designs containing boron with carbon equivalents (CE) greater than 0.50 to achieve the desired microstructures. The higher CE has a negative influence on weldability.

Effect of concrete strength gradation to the compressive strength of graded concrete, a numerical approach

Science.gov (United States)

Pratama, M. Mirza Abdillah; Aylie, Han; Gan, Buntara Sthenly; Umniati, B. Sri; Risdanareni, Puput; Fauziyah, Shifa

2017-09-01

Concrete casting, compacting method, and characteristic of the concrete material determine the performance of concrete as building element due to the material uniformity issue. Previous studies show that gradation in strength exists on building member by nature and negatively influence the load carrying capacity of the member. A pilot research had modeled the concrete gradation in strength with controllable variable and observed that the weakest material determines the strength of graded concrete through uniaxial compressive loading test. This research intends to confirm the recent finding by a numerical approach with extensive variables of strength disparity. The finite element analysis was conducted using the Strand7 nonlinear program. The results displayed that the increase of strength disparity in graded concrete models leads to the slight reduction of models strength. A substantial difference in displacement response is encountered on the models for the small disparity of concrete strength. However, the higher strength of concrete mix in the graded concrete models contributes to the rise of material stiffness that provides a beneficial purpose for serviceability of building members.

On the performance of circular concrete-filled high strength steel columns under axial loading

Directory of Open Access Journals (Sweden)

Mohamed Mahmoud El-Heweity

2012-06-01

Full Text Available This work presents a numerical study to investigate the performance of circular high-strength steel tubes filled with concrete (CFT under monotonic axial loading. A model is developed to implement the material constitutive relationships and non-linearity. Calibration against previous experimental data shows good agreement. A parametric study is then conducted using the model and compared with codes provisions. Strength and ductility of confined concrete are of primary concern. Variables considered are yield stress of steel tube and column diameter. The assessment of column performance is based on axial load carrying capacities and enhancements of both strength and ductility due to confinement. Two parameters namely strength enhancement factor (Kf and ductility index (μ are clearly defined and introduced for assessment. Results indicate that both concrete strength and ductility of CFT columns are enhanced but to different extents. The ductile behaviors are significantly evident. The increase in yield stress of steel tube has a minimal effect on concrete strength but pronounced effect on concrete ductility. However, reduction in ductility is associated with using high-tensile steel of Grade 70. The overall findings indicate that the use of high-strength tube in CFT columns is not promising. This finding may seriously be considered in seismic design.

Jet formation in cerium metal to examine material strength

Energy Technology Data Exchange (ETDEWEB)

Jensen, B. J., E-mail: bjjensen@lanl.gov; Cherne, F. J.; Prime, M. B.; Yeager, J. D.; Ramos, K. J.; Hooks, D. E.; Cooley, J. C.; Dimonte, G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Fezzaa, K. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Iverson, A. J.; Carlson, C. A. [National Security Technologies LLC, Los Alamos, New Mexico 87544 (United States)

2015-11-21

Examining the evolution of material properties at extreme conditions advances our understanding of numerous high-pressure phenomena from natural events like meteorite impacts to general solid mechanics and fluid flow behavior. Recent advances in synchrotron diagnostics coupled with dynamic compression platforms have introduced new possibilities for examining in-situ, spatially resolved material response with nanosecond time resolution. In this work, we examined jet formation from a Richtmyer-Meshkov instability in cerium initially shocked into a transient, high-pressure phase, and then released to a low-pressure, higher-temperature state. Cerium's rich phase diagram allows us to study the yield stress following a shock induced solid-solid phase transition. X-ray imaging was used to obtain images of jet formation and evolution with 2–3 μm spatial resolution. From these images, an analytic method was used to estimate the post-shock yield stress, and these results were compared to continuum calculations that incorporated an experimentally validated equation-of-state (EOS) for cerium coupled with a deviatoric strength model. Reasonable agreement was observed between the calculations and the data illustrating the sensitivity of jet formation on the yield stress values. The data and analysis shown here provide insight into material strength during dynamic loading which is expected to aid in the development of strength aware multi-phase EOS required to predict the response of matter at extreme conditions.

Photon strength functions

International Nuclear Information System (INIS)

Bergqvist, I.

1976-01-01

Methods for extracting photon strength functions are briefly discussed. We follow the Brink-Axel approach to relate the strength functions to the giant resonances observed in photonuclear work and summarize the available data on the E1, E2 and M1 resonances. Some experimental and theoretical problems are outlined. (author)

Predicting hand function in older adults: evaluations of grip strength, arm curl strength, and manual dexterity.

Science.gov (United States)

Liu, Chiung-Ju; Marie, Deana; Fredrick, Aaron; Bertram, Jessica; Utley, Kristen; Fess, Elaine Ewing

2017-08-01

Hand function is critical for independence in activities of daily living for older adults. The purpose of this study was to examine how grip strength, arm curl strength, and manual dexterous coordination contributed to time-based versus self-report assessment of hand function in community-dwelling older adults. Adults aged ≥60 years without low vision or neurological disorders were recruited. Purdue Pegboard Test, Jamar hand dynamometer, 30-second arm curl test, Jebsen-Taylor Hand Function Test, and the Late-Life Function and Disability Instrument were administered to assess manual dexterous coordination, grip strength, arm curl strength, time-based hand function, and self-report of hand function, respectively. Eighty-four adults (mean age = 72 years) completed the study. Hierarchical multiple regressions show that older adults with better arm curl strength (β = -.25, p function test. In comparison, older adults with better grip strength (β = .40, p function. The relationship between grip strength and hand function may be test-specific. Grip strength becomes a significant factor when the test requires grip strength to successfully complete the test tasks. Arm curl strength independently contributed to hand function in both time-based and self-report assessments, indicating that strength of extrinsic muscles of the hand are essential for hand function.

Influence of the welding process on martensitic high strength steel

Directory of Open Access Journals (Sweden)

Petr Hanus

2014-07-01

Full Text Available The subject of the study is martensitic 22MnB5 steels, which are used in the automotive industry. The main purpose of the performed analyses is a study of strength differences in heat affected zones of the spot welding. For the needs of the strength decrease assessment, the critical layer of the heat affected area was experimentally simulated. The aim of the work is to determine the most suitable methodology for evaluating the local changes of the elastic-plastic material response. The aim of this work is to determine the optimal methods for the determination of the yield strength and to find a firming trend in these zones.

Soft radiative strength in warm nuclei

International Nuclear Information System (INIS)

Becker, J A; Bernstein, L A; Garrett, P E; Nelson, R O; Schiller, A; Voinov, A; Agvaanluvsan, U; Algin, E; Belgya, T; Chankova, R; Guttormsen, M; Mitchell, G E; Rekstad, J; Siem, S

2004-01-01

Unresolved transitions in the nuclear γ-ray cascade produced in the decay of excited nuclei are best described by statistical concepts: a continuous radiative strength function (RSF) and level density yield mean values of transition matrix elements. Data on the soft (E γ < 3-4 MeV) RSF for transitions between warm states (i.e. states several MeV above the yrast line) have, however, remained elusive

Connection of crystallographic texture with anisotropy of yield strength of titanium alloy sheets

International Nuclear Information System (INIS)

Serebryannyj, V.N.; Koknaev, R.G.

1983-01-01

Using the programs developed in FORTRAN-4 algorithmic language for the ES-1022 computer the contribution of crystallographic texture to the anisotropy of yield strength in the sheet plane for warm-rolled sheets of α-titanium alloys VT1 and VT5-1, is evaluated. It is established, that experimental and calculation data for the sheet of VT1-0 agree satisfactorily in the angle range phi 40 deg the value anti M (phi) exceeds the experimental values σsub(0.2)(phi./σsub(0.2)(0). The results obtained for the sheet of the VT5-1 alloy show, that calculation and experimental data agree well for narrow angles (phi <= 60 deg) and at wider angles the values anti M(phi) exceed the values σsub(0.2)(phi)/σsub(0.2)(0). Calculation and experimental curves for the VT5-1 alloy on the whole agree better than for the VT1-0 one

Isometric shoulder strength in young swimmers.

Science.gov (United States)

McLaine, Sally J; Ginn, Karen A; Fell, James W; Bird, Marie-Louise

2018-01-01

The prevalence of shoulder pain in young swimmers is high. Shoulder rotation strength and the ratio of internal to external rotation strength have been reported as potential modifiable risk factors associated with shoulder pain. However, relative strength measures in elevated positions, which include flexion and extension, have not been established for the young swimmer. The aim of this study was to establish clinically useful, normative shoulder strength measures and ratios for swimmers (14-20 years) without shoulder pain. Cross-sectional, observational study. Swimmers (N=85) without a recent history of shoulder pain underwent strength testing of shoulder flexion and extension (in 140° abduction); and internal and external rotation (in 90° abduction). Strength tests were performed in supine using a hand-held dynamometer and values normalised to body weight. Descriptive statistics were calculated for strength and strength ratios (flexion:extension and internal:external rotation). Differences between groups (based on gender, history of pain, test and arm dominance) were explored using independent and paired t tests. Normative shoulder strength values and ratios were established for young swimmers. There was a significant difference (pdifferences in strength ratios. Relative strength of the dominant and non-dominant shoulders (except for extension); and for swimmers with and without a history of shoulder pain was not significantly different. A normal shoulder strength profile for the young swimmer has been established which provides a valuable reference for the clinician assessing shoulder strength in this population. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Structural strength of cancellous specimens from bovine femur under cyclic compression

Directory of Open Access Journals (Sweden)

Kaori Endo

2016-01-01

Full Text Available The incidence of osteoporotic fractures was estimated as nine million worldwide in 2000, with particular occurrence at the proximity of joints rich in cancellous bone. Although most of these fractures spontaneously heal, some fractures progressively collapse during the early post-fracture period. Prediction of bone fragility during progressive collapse following initial fracture is clinically important. However, the mechanism of collapse, especially the gradual loss of the height in the cancellous bone region, is not clearly proved. The strength of cancellous bone after yield stress is difficult to predict since structural and mechanical strength cannot be determined a priori. The purpose of this study was to identify whether the baseline structure and volume of cancellous bone contributed to the change in cancellous bone strength under cyclic loading. A total of fifteen cubic cancellous bone specimens were obtained from two 2-year-old bovines and divided into three groups by collection regions: femoral head, neck, and proximal metaphysis. Structural indices of each 5-mm cubic specimen were determined using micro-computed tomography. Specimens were then subjected to five cycles of uniaxial compressive loading at 0.05 mm/min with initial 20 N loading, 0.3 mm displacement, and then unloading to 0.2 mm with 0.1 mm displacement for five successive cycles. Elastic modulus and yield stress of cancellous bone decreased exponentially during five loading cycles. The decrease ratio of yield stress from baseline to fifth cycle was strongly correlated with bone volume fraction (BV/TV, r = 0.96, p < 0.01 and structural model index (SMI, r = − 0.81, p < 0.01. The decrease ratio of elastic modulus from baseline to fifth cycle was also correlated with BV/TV (r = 0.80, p < 0.01 and SMI (r = − 0.78, p < 0.01. These data indicate that structural deterioration of cancellous bone is associated with bone strength after yield stress. This study suggests that

At-home resistance tubing strength training increases shoulder strength in the trained and untrained limb.

Science.gov (United States)

Magnus, C R A; Boychuk, K; Kim, S Y; Farthing, J P

2014-06-01

The purpose was to determine if an at-home resistance tubing strength training program on one shoulder (that is commonly used in rehabilitation settings) would produce increases in strength in the trained and untrained shoulders via cross-education. Twenty-three participants were randomized to TRAIN (strength-trained one shoulder; n = 13) or CONTROL (no intervention; n = 10). Strength training was completed at home using resistance tubing and consisted of maximal shoulder external rotation, internal rotation, scaption, retraction, and flexion 3 days/week for 4 weeks. Strength was measured via handheld dynamometry and muscle size measured via ultrasound. For external rotation strength, the trained (10.9 ± 10.9%) and untrained (12.7 ± 9.6%) arm of TRAIN was significantly different than CONTROL (1.6 ± 13.2%; -2.7 ± 12.3%; pooled across arm; P tubing training program on one limb can produce increases in strength in both limbs, and has implications for rehabilitation after unilateral shoulder injuries. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

SU(N) instantons in the field strength approach to QCD

International Nuclear Information System (INIS)

Reinhardt, H.

1994-01-01

Field strength formulated Yang-Mills theory is confronted to the traditional formulation in terms of gauge fields. It is shown that both formulations yield the same semiclassics, in particular the same instanton physics. The field strength formulation is, however, superior at the tree level where it includes already a good deal of quantum fluctuations of the standard formulation. These quantum fluctuations break the scale invariance of classical QCD and give rise to an instanton interaction. The latter causes the instanton to condense and to form a homogeneous instanton solid. These instanton solids show up in the field strength approach as homogeneous (constant up to gauge transformations) vacuum solutions. A new class of SU(N) instantons is presented which are not embeddings of SU(N-1) instantons but have non-trivial SU(N) color structure and carry winding number n = N/(N 2 -1)/6. These novel instantons generate (after condensation) the lowest action homogeneous solutions of the field strength approach. (orig.)

Ultimate strength analysis of ring-stiffened cylinders subjected to hydrostatic pressure

International Nuclear Information System (INIS)

Park, Chi Mo

1990-01-01

In this study, ultimate strength analysis of ring-stiffened cylinders have been performed, considering the elasto-plastic large deflection. In the elasto-plastic analysis, von Mises yield criteria, the plastic flow theory and the layered approach have been adopted. In order to take into account the follower force effect of the hydrostatic pressure, the incremental load components have been updated at every loading step. As collapse modes, axisymmetric yielding, interframe shell buckling and general buckling are considered, while local buckling of ring-stiffener is not considered. Initial shape imperfection is assumed to be the elastic buckling mode to obtain the lower bound of the ultimate strength. Results of numerical analysis are compared with the experimental results to show the validity of the present approach. It has been drawn that the present numerical results are closely correlated with the experimental results. On the other hand, the effects of initial shape imperfection and condition on the ultimate strength have been investigated. (Author)

The Strengths Assessment Inventory: Reliability of a New Measure of Psychosocial Strengths for Youth

Science.gov (United States)

Brazeau, James N.; Teatero, Missy L.; Rawana, Edward P.; Brownlee, Keith; Blanchette, Loretta R.

2012-01-01

A new measure, the Strengths Assessment Inventory-Youth self-report (SAI-Y), was recently developed to assess the strengths of children and adolescents between the ages of 10 and 18 years. The SAI-Y differs from similar measures in that it provides a comprehensive assessment of strengths that are intrinsic to the individual as well as strengths…

Crack Arrest Toughness of Two High Strength Steels (AISI 4140 and AISI 4340)

Science.gov (United States)

Ripling, E. J.; Mulherin, J. H.; Crosley, P. B.

1982-04-01

The crack initiation toughness ( K c ) and crack arrest toughness ( K a ) of AISI 4140 and AISI 4340 steel were measured over a range of yield strengths from 965 to 1240 MPa, and a range of test temperatures from -53 to +74°C. Emphasis was placed on K a testing since these values are thought to represent the minimum toughness of the steel as a function of loading rate. At the same yield strengths and test temperatures, K a for the AISI 4340 was about twice as high as it was for the AISI 4140. In addition, the K a values showed a more pronounced transition temperature than the K c values, when the data were plotted as a function of test temperature. The transition appeared to be associated with a change in fracture mechanism from cleavage to dimpled rupture as the test temperature was increased. The occurrence of a “pop-in” behavior at supertransition temperatures has not been found in lower strength steels, and its evaluation in these high strength steels was possible only because they are not especially tough at their supertransition temperatures. There is an upper toughness limit at which pop-in will not occur, and this was found for the AISI 4340 steel when it was tempered to its lowest yield strength (965 MPa). All the crack arrest data were identified as plane strain values, while only about one-half of the initiation values could be classified this way.

High-strength shape memory steels alloyed with nitrogen

International Nuclear Information System (INIS)

Ullakko, K.; Jakovenko, P.T.; Gavriljuk, V.G.

1996-01-01

Since shape memory effect in Fe-Mn-Si systems was observed, increasing attention has been paid to iron based shape memory alloys due to their great technological potential. Properties of Fe-Mn-Si shape memory alloys have been improved by alloying with Cr, Ni, Co and C. A significant improvement on shape memory, mechanical and corrosion properties is attained by introducing nitrogen in Fe-Mn-Si based systems. By increasing the nitrogen content, strength of the matrix increases and the stacking fault energy decreases, which promote the formation of stress induced martensite and decrease permanent slip. The present authors have shown that nitrogen alloyed shape memory steels exhibit recoverable strains of 2.5--4.2% and recovery stresses of 330 MPa. In some cases, stresses over 700 MPa were attained at room temperature after cooling a constrained sample. Yield strengths of these steels can be as high as 1,100 MPa and tensile strengths over 1,500 MPa with elongations of 30%. In the present study, effect of nitrogen alloying on shape memory and mechanical properties of Fe-Mn-Si, Fe-Mn-Si-Cr-Ni and Fe-Mn-Cr-Ni-V alloys is studied. Nitrogen alloying is shown to exhibit a beneficial effect on shape memory properties and strength of these steels

Effects of strength training, detraining and retraining in muscle strength, hypertrophy and functional tasks in older female adults.

Science.gov (United States)

Correa, Cleiton S; Cunha, Giovani; Marques, Nise; Oliveira-Reischak, Ãlvaro; Pinto, Ronei

2016-07-01

Previous studies presented different results regarding the maintenance time of muscular adaptations after strength training and the ability to resume the gains on muscular performance after resumption of the training programme. This study aimed to verify the effect of strength training on knee extensors and elbow flexor muscle strength, rectus femoris muscle volume and functional performance in older female adults after 12 weeks of strength training, 1 year of detraining and followed by 12 weeks of retraining. Twelve sedentary older women performed 12 weeks of strength training, 1 year of detraining and 12 weeks of retraining. The strength training was performed twice a week, and the assessment was made four times: at the baseline, after the strength training, after the detraining and after the retraining. The knee extensor and elbow flexor strength, rectus femoris muscle volume and functional task were assessed. Strength of knee extensor and elbow flexor muscles, rectus femoris muscle volume and 30-s sit-to-stand increased from baseline to post-training (respectively, 40%, 70%, 38% and 46%), decreased after detraining (respectively, -36%, -64%, -35% and -43%) and increased again these parameters after retraining (35%, 68%, 36% and 42%). Strength training induces gains on strength and hypertrophy, also increased the performance on functional tasks after the strength training. The stoppage of the strength caused strength loss and reduction of functional performance. The resumption of the strength training promoted the same gains of muscular performance in older female adults. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Percentage Level of Tannin fur Rabbit for Leather Concerning Stitch Tearing Strength, Tearing Strength and Flexibility

Directory of Open Access Journals (Sweden)

Mustakim Mustakim

2012-02-01

Full Text Available The purpose of this study was to find out the appropriate of tannin level for rabbit fur leather concerning stitch tearing strength, tearing strength, and flexibility. The result were expected to contribute good information for the society, leather craftsman, and further researchers about fur leather tanning especially rabbit fur leather with tannin concerning stitch tearing strength, tearing strength and flexibility. The material that used were 12 pieces of four months of rabbit skin. The research method was Completely Randomized Design, consist of three treatments of tannin, they were: M1 (mimosa 15%, M2 (mimosa 20%, and M3 (mimosa 25%. Each of treatment hold on four repetition, the variables which measured were stitch tearing strength, tearing strength, and flexibility of fur leather. Data were  analysed by analysis variance followed by Duncan’s Multiple Range Test. The result of this research indicate that the use level of tannin give significant influence (P<0.05 among stitch tearing strength, tearing strength. It gave a very significant influence (P<0.01 for flexibility of rabbit fur leather. Based on the result, can be concluded that 25 % of tannin (mimosa, produce the best  result on stitch tearing strength and tearing strength. The increase of tannin offer will decrease the flexibility of fur leather but the lowest tannin produced the best flexibility of fur leather (15 percent. The best quality of rabbit fur leather produced by 25 % of tannin.   Keywords : leather, tannin, quality

The assessment of bond strength between heat damaged concrete and high strength fibre reinforced concrete

Science.gov (United States)

Zahid, M. Z. A. Mohd; Muhamad, K.

2017-09-01

The aim of this study is to assess the bond strength between heat damaged concrete and high strength fibre reinforced concrete (HPFRC). Firstly, this paper presents the various steps taken to prepare the HPFRC with self-compacting property. The minimum targeted slump flow is 600 mm and minimum targeted compressive strength is 80 MPa. The key mix variables considered are such as type of superplasticizer, water cement ratio and silica fume content. Then, the bond strength between the heat damaged concrete with HPFRC was examined. The experimental parameters are heating temperature, surface treatment technique and curing method and the results show that, all experimental parameters are significantly affected the bond strength between heat damaged concrete and HPFRC.

An investigation of improved strength and toughness of ausformed H13 steel

International Nuclear Information System (INIS)

Cha, Yong Chul; Yoon, Han Sang

1986-01-01

The effect of ausforming for AISI H13 steel was studied. Plastic deformation of metastable austenite increased the hardness and strength of the subsequently formed martensite. The increases in yield and tensile strength were proportional to the degree of austenite deformation without sacrifice of toughness, and large deformation (60%) resulted in significant increase in impact value. Furthermore, temper resistance up to 500 deg C, that is, consequent improvement in elevated-temperature strength property was demonstrated. These results can be interpreted as being attributed to the formation of cellular substructures which were fixed by alloy carbides. (Author)

Phase transformation and mechanical behavior of thermomechanically controlled processed high strength ordnance steel

International Nuclear Information System (INIS)

Bandyopadhyay, P.S.; Ghosh, S.K.; Kundu, S.; Chatterjee, S.

2013-01-01

A new low carbon titanium and niobium microalloyed steel has been thermomechanically processed in a pilot plant unit. Phase transformation phenomenon of the above steel during continuous cooling has been assessed. Evolution of microstructure and mechanical properties has also been studied at different finish rolling temperatures. A mixture of intragranular ferrite with granular bainite and bainitic ferrite along with inter-lath and intra-lath precipitation of (Ti, Nb)CN particles are the characteristic microstructural feature of air cooled steel. However, mixture of lower bainite and lath martensitic structure along with similar type (Ti, Nb)CN precipitate is observed in water quenched steel. High yield strength (896–948 MPa) with high tensile strength (974–1013 MPa) has been achieved with moderate ductility (16–17%) for the selected range of finish rolling temperature for air cooled steel. However, the water quenched steel yields higher yield strength (1240–1260 MPa) as well as higher tensile strength (1270–1285 MPa) but with lower ductility (13–14%) for the selected range of finish rolling temperature. Fairly good impact toughness values in the range of 50–89 J are obtained for the air cooled steel which are marginally higher than those of water quenched steel (42–81 J). - Highlights: ► New high strength steel has been processed in a pilot plant scale. ► Primarily granular bainite and bainitic ferrite are obtained in air cooled steel. ► Mixture of lower bainite and lath martensite is obtained in water quenched steel. ► (Ti, Nb)CN precipitate is obtained for both air cooled and water quenched steels. ► Highest strength with reasonable ductility has been achieved after water quenching

Phase transformation and mechanical behavior of thermomechanically controlled processed high strength ordnance steel

Energy Technology Data Exchange (ETDEWEB)

Bandyopadhyay, P.S. [Ordnance Development Centre, Metal and Steel Factory, Ishapore 743 144 (India); Ghosh, S.K., E-mail: skghosh@metal.becs.ac.in [Department of Metallurgy and Materials Engineering, Bengal Engineering and Science University, Shibpur, Howrah 711 103 (India); Kundu, S.; Chatterjee, S. [Department of Metallurgy and Materials Engineering, Bengal Engineering and Science University, Shibpur, Howrah 711 103 (India)

2013-02-15

A new low carbon titanium and niobium microalloyed steel has been thermomechanically processed in a pilot plant unit. Phase transformation phenomenon of the above steel during continuous cooling has been assessed. Evolution of microstructure and mechanical properties has also been studied at different finish rolling temperatures. A mixture of intragranular ferrite with granular bainite and bainitic ferrite along with inter-lath and intra-lath precipitation of (Ti, Nb)CN particles are the characteristic microstructural feature of air cooled steel. However, mixture of lower bainite and lath martensitic structure along with similar type (Ti, Nb)CN precipitate is observed in water quenched steel. High yield strength (896–948 MPa) with high tensile strength (974–1013 MPa) has been achieved with moderate ductility (16–17%) for the selected range of finish rolling temperature for air cooled steel. However, the water quenched steel yields higher yield strength (1240–1260 MPa) as well as higher tensile strength (1270–1285 MPa) but with lower ductility (13–14%) for the selected range of finish rolling temperature. Fairly good impact toughness values in the range of 50–89 J are obtained for the air cooled steel which are marginally higher than those of water quenched steel (42–81 J). - Highlights: ► New high strength steel has been processed in a pilot plant scale. ► Primarily granular bainite and bainitic ferrite are obtained in air cooled steel. ► Mixture of lower bainite and lath martensite is obtained in water quenched steel. ► (Ti, Nb)CN precipitate is obtained for both air cooled and water quenched steels. ► Highest strength with reasonable ductility has been achieved after water quenching.

Accelerated Strength Testing of Thermoplastic Composites

Science.gov (United States)

Reeder, J. R.; Allen, D. H.; Bradley, W. L.

1998-01-01

Constant ramp strength tests on unidirectional thermoplastic composite specimens oriented in the 90 deg. direction were conducted at constant temperatures ranging from 149 C to 232 C. Ramp rates spanning 5 orders of magnitude were tested so that failures occurred in the range from 0.5 sec. to 24 hrs. (0.5 to 100,000 MPa/sec). Below 204 C, time-temperature superposition held allowing strength at longer times to be estimated from strength tests at shorter times but higher temperatures. The data indicated that a 50% drop in strength might be expected for this material when the test time is increased by 9 orders of magnitude. The shift factors derived from compliance data applied well to the strength results. To explain the link between compliance and strength, a viscoelastic fracture model was investigated. The model, which used compliance as input, was found to fit the strength data only if the critical fracture energy was allowed to vary with temperature reduced stress rate. This variation in the critical parameter severely limits its use in developing a robust time-dependent strength model. The significance of this research is therefore seen as providing both the indication that a more versatile acceleration method for strength can be developed and the evidence that such a method is needed.

High strength ferritic alloy

International Nuclear Information System (INIS)

1977-01-01

A high strength ferritic steel is specified in which the major alloying elements are chromium and molybdenum, with smaller quantities of niobium, vanadium, silicon, manganese and carbon. The maximum swelling is specified for various irradiation conditions. Rupture strength is also specified. (U.K.)

Percentage Level of Tannin fur Rabbit for Leather Concerning Stitch Tearing Strength, Tearing Strength and Flexibility

OpenAIRE

Mustakim Mustakim; Aris Sri Widati; Lisa Purnaningtyas

2012-01-01

The purpose of this study was to find out the appropriate of tannin level for rabbit fur leather concerning stitch tearing strength, tearing strength, and flexibility. The result were expected to contribute good information for the society, leather craftsman, and further researchers about fur leather tanning especially rabbit fur leather with tannin concerning stitch tearing strength, tearing strength and flexibility. The material that used were 12 pieces of four months of rabbit skin. The re...

High-Strength Low-Alloy Steel Strengthened by Multiply Nanoscale Microstructures

Science.gov (United States)

Shen, Y. F.; Zuo, L.

Recently, we have being focused on improving the strength without sacrificing ductility of High-strength low-alloy (HSLA) steels by designing nanostructures. Several developments have been obtained, summarized as the following three parts: (a) Depressively nanoscale precipitates: A ferritic steel with finely dispersed precipitates reveals a yield strength of 760 MPa, approximately three times higher than that of conventional Ti-bearing high strength hot-rolled sheet steels, and its ultimate tensile strength reaches 850 MPa with an elongation-to-failure value of 18%. The finely dispersed TiC precipitates in the matrix provide matrix strengthening. The estimated magnitude of precipitation strengthening is around 458 MPa. The effects of the particle size, particle distribution and intrinsic particle strength have been investigated through dislocation dynamics (DD) simulations. The DD results show that strengthening is not only a function of the density of the nano-scale precipitates but also of their size. (b) Ultrafinely ferritic plate: An interstitial-free (IF) steel sheet with a cold-rolling reduction of 75% shows a high tensile strength (710MPa) while preserving a considerable plastic strain (13%). The ductility recovery with increasing the rolling reduction up to 75% is related with the decreasing both in lamellar spacings and cell blocks sizes. (c) Parallel nano-laminated austenite: A composite microstructure consisting of ferrite, bainitic ferrite (BF) laths and retained austenite (RA) platelets has been found for the steel with a chemical composition of 0.19C-0.30Si-1.76Mn-1.52Al (in mass fraction), processed with annealing and bainitic holding. The sample annealed at 820oC (for 120s) and partitioned at 400oC (for 300s) has the best combination of ultimate tensile strength (UTS, 682 MPa) and elongation to failure ( 70%) with about 26% of BF plates 16% RA in its microstructure.

Study on strength of thick reinforced concrete slab with opening - Part 2: Evaluation of the test results

International Nuclear Information System (INIS)

Hirai, T.; Itoh, M.; Takei, K.; Kanazu, T.; Abe, Y.; Takahashi, T.; Hayashi, N.; Sasaki, N.

1993-01-01

In comparing the strength of the partial models obtained from the test and the strength calculated by the various formulas for short span cantilevers based on recent research, it was found that the strength of the partial models coincided well with the calculated bending strength. It was confirmed that bending failure also preceded in the overall model from the tests. However various strengths such as the cracking strength and the yielding strength of rebars were larger, and displacements and strains in various parts were smaller than those in the partial models. It was attributed to the effects of circumferential distribution of the load. A convenient method was proposed for evaluation of the strength of the overall model. In this method, the overall model is divided into corbels, and the strength of the model is calculated as the sum of these corbels' strength. This method estimated the strength conveniently and conservatively. (author)

Effects of walking and strength training on walking capacity in individuals with claudication: meta-analysis

Directory of Open Access Journals (Sweden)

Alessandra de Souza Miranda

2013-06-01

Full Text Available CONTEXT: Over the past few years, several clinical trials have been performed to analyze the effects of exercise training on walking ability in patients with intermittent claudication (IC. However, it remains unclear which type of physical exercise provides the maximum benefits in terms of walking ability. OBJECTIVE: To analyze, by means of a meta-analysis, the effects of walking and strength training on the walking capacity in patients with IC. METHODS: Papers analyzing the effects of walking and strength training programs in patients with IC were browsed on the Medline, Lilacs, and Cochrane databases. Randomized clinical trials scoring >4 on the Physiotherapy Evidence Database (PEDro scale and assessing claudication distance (CD and total walking distance (TWD were included in the review. RESULTS: Walking and strength training yielded increases in CD and TWD (P < 0.05. However, walking training yielded greater increases than strength training (P = 0.02. CONCLUSION: Walking and strength training improve walking capacity in patients with IC. However, greater improvements in TWD are obtained with walking training.

Dependence of the giant dipole strength function on excitation energy

International Nuclear Information System (INIS)

Draper, J.E.; Newton, J.O.; Sobotka, L.G.; Lindenberger, H.; Wozniak, G.J.; Moretto, L.G.; Stephens, F.S.; Diamond, R.M.; McDonald, R.J.

1982-01-01

Spectra of γ rays associated with deep-inelastic products from the 1150-MeV 136 Xe+ 181 Ta reaction have been measured. The yield of 10--20-MeV γ rays initially increases rapidly with the excitation energy of the products and then more slowly for excitation energies in excess of 120 MeV. Statistical-model calculations with ground-state values of the giant dipole strength function fail to reproduce the shape of the measured γ-ray spectra. This suggests a dependence of the giant dipole strength function on excitation energy

[Loading and strength of single- and multi-unit fixed dental prostheses 2. Strength

NARCIS (Netherlands)

Baat, C. de; Witter, D.J.; Meijers, C.C.A.J.; Vergoossen, E.L.; Creugers, N.H.J.

2014-01-01

The ultimate strength of a dental prosthesis is defined as the strongest loading force applied to the prosthesis until afracture failure occurs. Important key terms are strength, hardness, toughness and fatigue. Relatively prevalent complications of single- and multi-unit fixed dental prostheses are

Experimental Investigation into Corrosion Effect on Mechanical Properties of High Strength Steel Bars under Dynamic Loadings

Directory of Open Access Journals (Sweden)

Hui Chen

2018-01-01

Full Text Available The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.

Testing compression strength of wood logs by drilling resistance

Science.gov (United States)

Kalny, Gerda; Rados, Kristijan; Rauch, Hans Peter

2017-04-01

Soil bioengineering is a construction technique using biological components for hydraulic and civil engineering solutions, based on the application of living plants and other auxiliary materials including among others log wood. Considering the reliability of the construction it is important to know about the durability and the degradation process of the wooden logs to estimate and retain the integral performance of a soil bioengineering system. An important performance indicator is the compression strength, but this parameter is not easy to examine by non-destructive methods. The Rinntech Resistograph is an instrument to measure the drilling resistance by a 3 mm wide needle in a wooden log. It is a quasi-non-destructive method as the remaining hole has no weakening effects to the wood. This is an easy procedure but result in values, hard to interpret. To assign drilling resistance values to specific compression strengths, wooden specimens were tested in an experiment and analysed with the Resistograph. Afterwards compression tests were done at the same specimens. This should allow an easier interpretation of drilling resistance curves in future. For detailed analyses specimens were investigated by means of branch inclusions, cracks and distances between annual rings. Wood specimens are tested perpendicular to the grain. First results show a correlation between drilling resistance and compression strength by using the mean drilling resistance, average width of the annual rings and the mean range of the minima and maxima values as factors for the drilling resistance. The extended limit of proportionality, the offset yield strength and the maximum strength were taken as parameters for compression strength. Further investigations at a second point in time strengthen these results.

Anisotropic Concrete Compressive Strength

DEFF Research Database (Denmark)

Gustenhoff Hansen, Søren; Jørgensen, Henrik Brøner; Hoang, Linh Cao

2017-01-01

When the load carrying capacity of existing concrete structures is (re-)assessed it is often based on compressive strength of cores drilled out from the structure. Existing studies show that the core compressive strength is anisotropic; i.e. it depends on whether the cores are drilled parallel...

Effects of neck strength training on isometric neck strength in rugby union players.

Science.gov (United States)

Geary, Kevin; Green, Brian S; Delahunt, Eamonn

2014-11-01

To investigate the effectiveness of a neck strengthening program on the isometric neck strength profile of male rugby union players. Controlled laboratory study. Professional rugby union club. Fifteen professional and 10 semiprofessional rugby union players. The 15 professional players undertook a 5-week neck strengthening intervention, which was performed twice per week, whereas the 10 semiprofessional players acted as the control group. Isometric strength of the neck musculature was tested using a hand-held dynamometer, for flexion (F), extension (E), left-side flexion (LSF), and right-side flexion (RSF). Preintervention and postintervention evaluations were undertaken. No significant between-group differences in isometric neck strength were noted preintervention. A significant main effect for time was observed (P isometric neck strength in all planes after the 5-week intervention (F preintervention = 334.45 ± 39.31 N vs F postintervention 396.05 ± 75.55 N; E preintervention = 606.19 ± 97.34 vs E postintervention = 733.88 ± 127.16 N; LSF preintervention = 555.56 ± 88.34 N vs LSF postintervention = 657.14 ± 122.99 N; RSF preintervention = 570.00 ± 106.53 N vs RSF postintervention = 668.00 ± 142.18 N). No significant improvement in neck strength was observed for control group participants. The results of the present study indicate that a 5-week neck strengthening program improves isometric neck strength in rugby union players, which may have implications for injury prevention, screening, and rehabilitation. The strengthening program described in the present study may facilitate rehabilitation specialists in the development of neck injury prevention, screening, and rehabilitation protocols.

Experimental knee pain reduces muscle strength

DEFF Research Database (Denmark)

Henriksen, Marius; Mortensen, Sara Rosager; Aaboe, Jens

2011-01-01

Pain is the principal symptom in knee pathologies and reduced muscle strength is a common observation among knee patients. However, the relationship between knee joint pain and muscle strength remains to be clarified. This study aimed at investigating the changes in knee muscle strength following...... experimental knee pain in healthy volunteers, and if these changes were associated with the pain intensities. In a crossover study, 18 healthy subjects were tested on 2 different days. Using an isokinetic dynamometer, maximal muscle strength in knee extension and flexion was measured at angular velocities 0....... Knee pain reduced the muscle strength by 5 to 15% compared to the control conditions (P knee extension and flexion at all angular velocities. The reduction in muscle strength was positively correlated to the pain intensity. Experimental knee pain significantly reduced knee extension...

Interviewing to Understand Strengths

Science.gov (United States)

Hass, Michael R.

2018-01-01

Interviewing clients about their strengths is an important part of developing a complete understanding of their lives and has several advantages over simply focusing on problems and pathology. Prerequisites for skillfully interviewing for strengths include the communication skills that emerge from a stance of not knowing, developing a vocabulary…

The added value of measuring thumb and finger strength when comparing strength measurements in hypoplastic thumb patients.

Science.gov (United States)

Molenaar, H M Ties; Selles, Ruud W; de Kraker, Marjolein; Stam, Henk J; Hovius, Steven E R

2013-10-01

When interventions to the hand are aimed at improving function of specific fingers or the thumb, the RIHM (Rotterdam Intrinsic Hand Myometer) is a validated tool and offers more detailed information to assess strength of the involved joints besides grip and pinch measurements. In this study, strength was measured in 65 thumbs in 40 patients diagnosed with thumb hypoplasia. These 65 thumbs were classified according to Blauth. Longitudinal radial deficiencies were also classified. The strength measurements comprised of grip, tip, tripod and key pinch. Furthermore palmar abduction and opposition of the thumb as well as abduction of the index and little finger were measured with the RIHM. For all longitudinal radial deficiency patients, grip and pinch strength as well as palmar abduction and thumb opposition were significantly lower than reference values (P<0.001). However, strength in the index finger abduction and the little finger abduction was maintained or decreased to a lesser extent according to the degree of longitudinal radial deficiency. All strength values decreased with increasing Blauth-type. Blauth-type II hands (n=15) with flexor digitorum superficialis 4 opposition transfer including stabilization of the metacarpophalangeal joint showed a trend toward a higher opposition strength without reaching statistical significance (P=0.094),however compared to non-operated Blauth-type II hands (n=6) they showed a lower grip strength (P=0.019). The RIHM is comparable in accuracy to other strength dynamometers. Using the RIHM, we were able to illustrate strength patterns on finger-specific level, showing added value when evaluating outcome in patients with hand related problems. © 2013.

Is grip strength a predictor for total muscle strength in healthy children, adolescents, and young adults?

NARCIS (Netherlands)

Wind, Anne E.; Takken, Tim; Helders, Paul J. M.; Engelbert, Raoul H. H.

2010-01-01

The primary purpose of this study was to examine whether grip strength is related to total muscle strength in children, adolescents, and young adults. The second purpose was to provide reference charts for grip strength, which could be used in the clinical and research setting. This cross-sectional

Crushing strength of HTGR fuel particles

International Nuclear Information System (INIS)

Lackey, W.J.; Stinton, D.P.; Davis, L.E.; Beatty, R.L.

1976-01-01

The whole-particle crushing strengths of High-Temperature Gas-Cooled Reactor fertile and fissile coated particles were measured and correlated with fabrication procedures. The crushing strength of Biso-coated fertile particles was increased by the following factors: (1) increasing the outer coating thickness by 10 μm increased strengths by 0.3 lb (1.3 N) for annealed particles and by 0.5 lb (2.2 N) for unannealed particles. (2) An 1800 0 C postcoating anneal increased strengths by 1 lb (4.4 N) for particles with thick outer coatings and by 2 lb (8.9 N) for particles having thin coatings. (3) Increasing the inner coating density by 0.1 g/cm 3 increased strength by 0.6 lb (2.7 N). The crushing strength of Triso-coated fissile particles was proportional to the thickness of the SiC coatings, and strength decreased on annealing by about 0.2 lb (0.9 N) when a porous plate was used to distribute the coating gas and by about 1.5 lb (6.7 N) when a conical gas distributor was used. The strengths of fertile and fissile coated particles as well as uncoated kernels appear adequate to allow fuel fabrication without excessive particle damage

The Importance of Muscular Strength: Training Considerations.

Science.gov (United States)

Suchomel, Timothy J; Nimphius, Sophia; Bellon, Christopher R; Stone, Michael H

2018-04-01

This review covers underlying physiological characteristics and training considerations that may affect muscular strength including improving maximal force expression and time-limited force expression. Strength is underpinned by a combination of morphological and neural factors including muscle cross-sectional area and architecture, musculotendinous stiffness, motor unit recruitment, rate coding, motor unit synchronization, and neuromuscular inhibition. Although single- and multi-targeted block periodization models may produce the greatest strength-power benefits, concepts within each model must be considered within the limitations of the sport, athletes, and schedules. Bilateral training, eccentric training and accentuated eccentric loading, and variable resistance training may produce the greatest comprehensive strength adaptations. Bodyweight exercise, isolation exercises, plyometric exercise, unilateral exercise, and kettlebell training may be limited in their potential to improve maximal strength but are still relevant to strength development by challenging time-limited force expression and differentially challenging motor demands. Training to failure may not be necessary to improve maximum muscular strength and is likely not necessary for maximum gains in strength. Indeed, programming that combines heavy and light loads may improve strength and underpin other strength-power characteristics. Multiple sets appear to produce superior training benefits compared to single sets; however, an athlete's training status and the dose-response relationship must be considered. While 2- to 5-min interset rest intervals may produce the greatest strength-power benefits, rest interval length may vary based an athlete's training age, fiber type, and genetics. Weaker athletes should focus on developing strength before emphasizing power-type training. Stronger athletes may begin to emphasize power-type training while maintaining/improving their strength. Future research should

Modern high strength QT, TM and duplex-stainless steels

Energy Technology Data Exchange (ETDEWEB)

Bocquet, P. [Industeel (France); Luxenburger, G. [Aktiengesellschaft der Dillinger Huettenwerke, Dillingen/Saar (Germany); Porter, D. [Rautaruukki (Finland); Ericsson, C. [Avesta Polarit (Sweden)

2003-07-01

Pressure vessels are commonly manufactured with normalised steel grades with a yield strength up to 355 MPa or with austenitic stainless steels when corrosion as to be considered. From three decades, modern steels with higher mechanical properties - up to yield strength of 960 Mpa - are available and largely used for other applications where weight saving is of major importance as per off-shore, bridges, cranes, shipbuilding, line pipes.. The paper presents these modern steel's families - TMCP (Thermo Mechanically Controlled Process), QT (Quenched and Tempered) and Duplex (austeno-ferritic) stainless - in comparison with the normalised and austenitic steel grades. The following aspects are presented: the main mechanical properties (tensile and Charpy) as per the requirements of the standards for pressure equipment; some examples of use of these modern steels in the industry are given; the limitations of the forming conditions are considered; the weldability aspects and welds properties are developed; the interest of the PWHT (Post Weld Heat Treatment) is discussed. (orig.)

Modern high strength QT, TM and duplex-stainless steels

International Nuclear Information System (INIS)

Bocquet, P.; Luxenburger, G.; Porter, D.; Ericsson, C.

2003-01-01

Pressure vessels are commonly manufactured with normalised steel grades with a yield strength up to 355 MPa or with austenitic stainless steels when corrosion as to be considered. From three decades, modern steels with higher mechanical properties - up to yield strength of 960 Mpa - are available and largely used for other applications where weight saving is of major importance as per off-shore, bridges, cranes, shipbuilding, line pipes.. The paper presents these modern steel's families - TMCP (Thermo Mechanically Controlled Process), QT (Quenched and Tempered) and Duplex (austeno-ferritic) stainless - in comparison with the normalised and austenitic steel grades. The following aspects are presented: the main mechanical properties (tensile and Charpy) as per the requirements of the standards for pressure equipment; some examples of use of these modern steels in the industry are given; the limitations of the forming conditions are considered; the weldability aspects and welds properties are developed; the interest of the PWHT (Post Weld Heat Treatment) is discussed. (orig.)

Feasibility of monitoring the strength of HTGR core support graphite: Part III

International Nuclear Information System (INIS)

Morgan, W.C.; Davis, T.J.; Thomas, M.T.

1983-02-01

Methods are being developed to monitor, in-situ, the strength changes of graphite core-support components in a High-Temperature Gas-Cooled Reactor (HTGR). The results reported herein pertain to the development of techniques for monitoring the core-support blocks; the PGX graphite used in these studies is the grade used for the core-support blocks of the Fort St. Vrain HTGR, and is coarser-grained than the grades used in our previous investigations. The through-transmission ultrasonic velocity technique, developed for monitoring strength of the core-support posts, is not suitable for use on the core-support blocks. Eddy-current and ultrasonic backscattering techniques have been shown to be capable of measuring the density-depth profile in oxidized PGX and, combined with a correlation of strength versus density, could yield an estimate of the strength-depth profile of in-service HTGR core support blocks. Correlations of strength versus density and other properties, and progress on the development of the eddy-current and ultrasonic backscattering techniques are reported

Interseason variability in isokinetic strength and poor correlation with Nordic hamstring eccentric strength in football players.

Science.gov (United States)

van Dyk, N; Witvrouw, E; Bahr, R

2018-04-25

In elite sport, the use of strength testing to establish muscle function and performance is common. Traditionally, isokinetic strength tests have been used, measuring torque during concentric and eccentric muscle action. A device that measures eccentric hamstring muscle strength while performing the Nordic hamstring exercise is now also frequently used. The study aimed to investigate the variability of isokinetic muscle strength over time, for example, between seasons, and the relationship between isokinetic testing and the new Nordic hamstring exercise device. All teams (n = 18) eligible to compete in the premier football league in Qatar underwent a comprehensive strength assessment during their periodic health evaluation at Aspetar Orthopaedic and Sports Medicine Hospital in Qatar. Isokinetic strength was investigated for measurement error, and correlated to Nordic hamstring exercise strength. Of the 529 players included, 288 players had repeated tests with 1/2 seasons between test occasions. Variability (measurement error) between test occasions was substantial, as demonstrated by the measurement error (approximately 25 Nm, 15%), whether separated by 1 or 2 seasons. Considering hamstring injuries, the same pattern was observed among injured (n = 60) and uninjured (n = 228) players. A poor correlation (r = .35) was observed between peak isokinetic hamstring eccentric torque and Nordic hamstring exercise peak force. The strength imbalance between limbs calculated for both test modes was not correlated (r = .037). There is substantial intraindividual variability in all isokinetic test measures, whether separated by 1 or 2 seasons, irrespective of injury. Also, eccentric hamstring strength and limb-to-limb imbalance were poorly correlated between the isokinetic and Nordic hamstring exercise tests. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Comparison of Thermal Stability of Dry High-strength Concrete and Wet High-strength Concrete

Science.gov (United States)

Musorina, Tatiana; Katcay, Aleksandr; Selezneva, Anna; Kamskov, Victor

2018-03-01

High-strength concrete is a modern material, which occupies it`s own niche on the construction material market. It is applicable in a large-scale high-rise construction, particularly an underground construction is a frequently used solution for a space saving. Usually underground structure is related to a wet usage environment. Though not all properties of the high-strength concrete are investigated to the full extent. Under adverse climatic conditions of the Russian Federation one of the most important properties for constructional materials is a thermal capacity. Therefore, the main purpose of the paper is to compare a thermal capacity of the high-strength concrete in humid conditions and a thermal capacity of the high-strength concrete in dry operational condition. During the study dependency between thermal capacity and design wall thickness and ambient humidity has to be proven with two experiments. As a result the theoretical relation between thermal capacity characteristic - thermal inertia and wall thickness and ambient humidity was confirmed by the experimental data. The thermal capacity of a building is in direct ratio to the construction thickness. It follows from the experiments and calculations that wet high-strength concrete has less thermal stability.

Models for predicting compressive strength and water absorption of ...

African Journals Online (AJOL)

This work presents a mathematical model for predicting the compressive strength and water absorption of laterite-quarry dust cement block using augmented Scheffe's simplex lattice design. The statistical models developed can predict the mix proportion that will yield the desired property. The models were tested for lack of ...

Strength development in concrete with wood ash blended cement and use of soft computing models to predict strength parameters.

Science.gov (United States)

Chowdhury, S; Maniar, A; Suganya, O M

2015-11-01

In this study, Wood Ash (WA) prepared from the uncontrolled burning of the saw dust is evaluated for its suitability as partial cement replacement in conventional concrete. The saw dust has been acquired from a wood polishing unit. The physical, chemical and mineralogical characteristics of WA is presented and analyzed. The strength parameters (compressive strength, split tensile strength and flexural strength) of concrete with blended WA cement are evaluated and studied. Two different water-to-binder ratio (0.4 and 0.45) and five different replacement percentages of WA (5%, 10%, 15%, 18% and 20%) including control specimens for both water-to-cement ratio is considered. Results of compressive strength, split tensile strength and flexural strength showed that the strength properties of concrete mixture decreased marginally with increase in wood ash contents, but strength increased with later age. The XRD test results and chemical analysis of WA showed that it contains amorphous silica and thus can be used as cement replacing material. Through the analysis of results obtained in this study, it was concluded that WA could be blended with cement without adversely affecting the strength properties of concrete. Also using a new statistical theory of the Support Vector Machine (SVM), strength parameters were predicted by developing a suitable model and as a result, the application of soft computing in structural engineering has been successfully presented in this research paper.

Comparison and Analysis of Steel Frame Based on High Strength Column and Normal Strength Column

Science.gov (United States)

Liu, Taiyu; An, Yuwei

2018-01-01

The anti-seismic performance of high strength steel has restricted its industrialization in civil buildings. In order to study the influence of high strength steel column on frame structure, three models are designed through MIDAS/GEN finite element software. By comparing the seismic performance and economic performance of the three models, the three different structures are comprehensively evaluated to provide some references for the development of high strength steel in steel structure.

Electrokinetic transport of aerobic microorganisms under low-strength electric fields.

Science.gov (United States)

Maillacheruvu, Krishnanand Y; Chinchoud, Preethi R

2011-01-01

To investigate the feasibility of utilizing low strength electric fields to transport commonly available mixed cultures such as those from an activated sludge process, bench scale batch reactor studies were conducted in sand and sandy loam soils. A readily biodegradable substrate, dextrose, was used to test the activity of the transported microorganisms. Electric field strengths of 7V, 10.5V, and 14V were used. Results from this investigation showed that an electric field strength of 0.46 Volts per cm was sufficient to transport activated sludge microorganisms across a sandy loam soil across a distance of about 8 cm in 72 h. More importantly, the electrokinetically transported microbial culture remained active and viable after the transport process and was biodegrade 44% of the dextrose in the soil medium. Electrokinetic treatment without microorganisms resulted in removal of 37% and the absence of any treatment yielded a removal of about 15%.

Strength of mortar containing rubber tire particle

Science.gov (United States)

Jusoh, M. A.; Abdullah, S. R.; Adnan, S. H.

2018-04-01

The main focus in this investigation is to determine the strength consist compressive and tensile strength of mortar containing rubber tire particle. In fact, from the previous study, the strength of mortar containing waste rubber tire in mortar has a slightly decreases compare to normal mortar. In this study, rubber tire particle was replacing on volume of fine aggregate with 6%. 9% and 12%. The sample were indicated M0 (0%), M6 (6%), M9 (9%) and M12 (12%). In this study, two different size of sample used with cube 100mm x 100mm x 100mm for compressive strength and 40mm x 40mm x 160mm for flexural strength. Morphology test was conducted by using Scanning electron microscopic (SEM) were done after testing compressive strength test. The concrete sample were cured for day 3, 7 and 28 before testing. Results compressive strength and flexural strength of rubber mortar shown improved compare to normal mortar.

Tensile and shear methods for measuring strength of bilayer tablets.

Science.gov (United States)

Chang, Shao-Yu; Li, Jian-Xin; Sun, Changquan Calvin

2017-05-15

Both shear and tensile measurement methods have been used to quantify interfacial bonding strength of bilayer tablets. The shear method is more convenient to perform, but reproducible strength data requires careful control of the placement of tablet and contact point for shear force application. Moreover, data obtained from the shear method depend on the orientation of the bilayer tablet. Although more time-consuming to perform, the tensile method yields data that are straightforward to interpret. Thus, the tensile method is preferred in fundamental bilayer tableting research to minimize ambiguity in data interpretation. Using both shear and tensile methods, we measured the mechanical strength of bilayer tablets made of several different layer combinations of lactose and microcrystalline cellulose. We observed a good correlation between strength obtained by the tensile method and carefully conducted shear method. This suggests that the shear method may be used for routine quality test of bilayer tablets during manufacturing because of its speed and convenience, provided a protocol for careful control of the placement of the tablet interface, tablet orientation, and blade is implemented. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect Of RPC Compositions On: Compressive Strength and Absorption

Directory of Open Access Journals (Sweden)

Ahmed Sultan Ali

2016-03-01

Full Text Available Concrete is a critical material for the construction of infrastructure facilities throughout the world. A new material known as Reactive Powder Concrete (RPC, or sometimes called Ultra-High Performance Concrete (UHPC, is becoming available that differs significantly from traditional concretes. It is an ultra high strength and high ductility composite material with advanced mechanical properties. It consists of special concrete whose microstructure is optimized by precise gradation of all particles in the mix to yield maximum density. Different RPC mixes in the experimental investigation of the present study the mechanical properties of RPC including compressive strength, density and absorption. The main variables used in the production of the different RPC mixes of the present research are three, namely, type of pozzolanic admixture (metakaolin, micro silica, and silica fume, type of fibers (steel and polypropylene fibers and volume fraction of fibers (1.0,1.5, and 2.0%. The experimental results indicated that RPC mixes with silica fume gave the highest values of compressive strength and density and lowest value of absorption in comparison with RPC using micro silica or metakaolin where metakaolin was the third in such comparisons. However the RPC mixes used in the present investigation gave group compressive strength ranging between 164 -195 MPa. It was also found that the use of steel fibers with high volume fraction (2% in an RPC mix increases the compressive strength by 8% and density of the concrete by 2.5% and reduces its absorption by 13%, unlike an RPC mix using polypropylene fibers of lesser volume fraction.

High strength alloys

Science.gov (United States)

Maziasz, Phillip James [Oak Ridge, TN; Shingledecker, John Paul [Knoxville, TN; Santella, Michael Leonard [Knoxville, TN; Schneibel, Joachim Hugo [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Vinegar, Harold J [Bellaire, TX; John, Randy Carl [Houston, TX; Kim, Dong Sub [Sugar Land, TX

2010-08-31

High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tubular that is at least partially made from a material containing at least one of the metal alloys.

Strength development in concrete with wood ash blended cement and use of soft computing models to predict strength parameters

Directory of Open Access Journals (Sweden)

S. Chowdhury

2015-11-01

Full Text Available In this study, Wood Ash (WA prepared from the uncontrolled burning of the saw dust is evaluated for its suitability as partial cement replacement in conventional concrete. The saw dust has been acquired from a wood polishing unit. The physical, chemical and mineralogical characteristics of WA is presented and analyzed. The strength parameters (compressive strength, split tensile strength and flexural strength of concrete with blended WA cement are evaluated and studied. Two different water-to-binder ratio (0.4 and 0.45 and five different replacement percentages of WA (5%, 10%, 15%, 18% and 20% including control specimens for both water-to-cement ratio is considered. Results of compressive strength, split tensile strength and flexural strength showed that the strength properties of concrete mixture decreased marginally with increase in wood ash contents, but strength increased with later age. The XRD test results and chemical analysis of WA showed that it contains amorphous silica and thus can be used as cement replacing material. Through the analysis of results obtained in this study, it was concluded that WA could be blended with cement without adversely affecting the strength properties of concrete. Also using a new statistical theory of the Support Vector Machine (SVM, strength parameters were predicted by developing a suitable model and as a result, the application of soft computing in structural engineering has been successfully presented in this research paper.

Microstructural effects on the yield strength and its temperature dependence in a bainitic precipitation hardened Cr-Mo-V steel

International Nuclear Information System (INIS)

Toerroenen, K.; Kotilainen, H.; Nenonen, P.

1980-03-01

The plastic deformation behaviour of a precipitation hardened bainitic Cr-Mo-V steel is analyzed at ambient and low temperatures. The temperature dependent component of the yield strength is composed of the Peierls-Nabarro force and also partly of the strengthening contribution of the lath- and cell boundaries or the solid solution hardening. The temperature dependence below 230 K is in accordance with the models presented by Yanoshevich and Ryvkina as well as Dorn and Rajnak. The temperature independent component can be calculated merely from the dislocation density, which is stabilized by the vanadium-rich carbides. The linear additivity cannot be used for the superposition of the strengthening effects of various strengthening parameters, By using the phenomenological approach starting from the dislocation movement mechanisms upon yielding the laws for the superposition are discussed. (author)

Fatigue strength of repaired cracks in welded connections made of very high strength steels

NARCIS (Netherlands)

Akyel, A.

2017-01-01

For cyclically loaded structures, fatigue design becomes one of the important design criteria. The state of art shows that with modification of the conventional structural design methodology, the use of very high strength steels may have a positive effect on fatigue strength of welded connections.

Strength of Fibrous Composites

CERN Document Server

Huang, Zheng-Ming

2012-01-01

"Strength of Fibrous Composites" addresses evaluation of the strength of a fibrous composite by using its constituent material properties and its fiber architecture parameters. Having gone through the book, a reader is able to predict the progressive failure behavior and ultimate strength of a fibrous laminate subjected to an arbitrary load condition in terms of the constituent fiber and matrix properties, as well as fiber geometric parameters. The book is useful to researchers and engineers working on design and analysis for composite materials. Dr. Zheng-Ming Huang is a professor at the School of Aerospace Engineering & Applied Mechanics, Tongji University, China. Mr. Ye-Xin Zhou is a PhD candidate at the Department of Mechanical Engineering, the University of Hong Kong, China.

Effect of Curing Temperature Histories on the Compressive Strength Development of High-Strength Concrete

Directory of Open Access Journals (Sweden)

Keun-Hyeok Yang

2015-01-01

Full Text Available This study examined the relative strength-maturity relationship of high-strength concrete (HSC specifically developed for nuclear facility structures while considering the economic efficiency and durability of the concrete. Two types of mixture proportions with water-to-binder ratios of 0.4 and 0.28 were tested under different temperature histories including (1 isothermal curing conditions of 5°C, 20°C, and 40°C and (2 terraced temperature histories of 20°C for an initial age of individual 1, 3, or 7 days and a constant temperature of 5°C for the subsequent ages. On the basis of the test results, the traditional maturity function of an equivalent age was modified to consider the offset maturity and the insignificance of subsequent curing temperature after an age of 3 days on later strength of concrete. To determine the key parameters in the maturity function, the setting behavior, apparent activation energy, and rate constant of the prepared mixtures were also measured. This study reveals that the compressive strength development of HSC cured at the reference temperature for an early age of 3 days is insignificantly affected by the subsequent curing temperature histories. The proposed maturity approach with the modified equivalent age accurately predicts the strength development of HSC.

Strength training for children and adolescents.

Science.gov (United States)

Faigenbaum, A D

2000-10-01

The potential benefits of youth strength training extend beyond an increase in muscular strength and may include favorable changes in selected health- and fitness-related measures. If appropriate training guidelines are followed, regular participation in a youth strength-training program has the potential to increase bone mineral density, improve motor performance skills, enhance sports performance, and better prepare our young athletes for the demands of practice and competition. Despite earlier concerns regarding the safety and efficacy of youth strength training, current public health objectives now aim to increase the number of boys and girls age 6 and older who regularly participate in physical activities that enhance and maintain muscular fitness. Parents, teachers, coaches, and healthcare providers should realize that youth strength training is a specialized method of conditioning that can offer enormous benefit but at the same time can result in serious injury if established guidelines are not followed. With qualified instruction, competent supervision, and an appropriate progression of the volume and intensity of training, children and adolescents cannot only learn advanced strength training exercises but can feel good about their performances, and have fun. Additional clinical trails involving children and adolescents are needed to further explore the acute and chronic effects of strength training on a variety of anatomical, physiological, and psychological parameters.

Effect of 8 weeks of free-weight and machine-based strength training on strength and power performance

OpenAIRE

Wirth Klaus; Keiner Michael; Hartmann Hagen; Sander Andre; Mickel Christoph

2016-01-01

Abstract The aim of this study was to evaluate the effectiveness of free-weight and machine-based exercises to increase different strength and speed-strength variables. One hundred twenty male participants (age: 23.8 ? 2.5 years; body height: 181.0 ? 6.8 cm; body mass: 80.2 ? 8.9 kg) joined the study. The 2 experimental groups completed an 8 week periodized strength training program that included 2 training sessions per week. The exercises that were used in the strength training programs were...

Effectiveness of acute in-hospital physiotherapy with knee-extension strength training in reducing strength deficits in patients with a hip fracture: A randomised controlled trial.

Directory of Open Access Journals (Sweden)

Lise Kronborg

Full Text Available Is acute in-hospital physiotherapy with additional progressive knee-extension strength training (ST of the fractured limb more effective in reducing knee-extension strength deficit at follow-up compared to physiotherapy without strength training in patients with a hip fracture?Assessor blinded, randomised controlled trial with intention-to-treat analysis.90 patients with a hip fracture admitted to an acute orthopaedic Hip Fracture Unit at a university hospital between October 2013 and May 2015.Daily physiotherapy with or without progressive knee-extension strength training (10RM, 3 x 10 repetitions, of the fractured limb using ankle weight cuffs conducted by ward physical therapists during hospital stay.Primary outcome was the change in maximal isometric knee-extension strength in the fractured limb in percentage of the non-fractured limb from inclusion to postoperative day 10 or discharge (follow-up. Secondary outcome was Timed Up and Go test measured early after surgery and at follow-up.In the intention-to-treat analysis of between-group differences, the primary outcome improved 8.1% (95% CI -2.3; 18.4 by additional strength training from baseline to follow-up. In the per-protocol analysis of non-missing data, significant between-group improvements by 10.5% (95% CI 0.3; 20.7 were found in favour of additional ST. No significant between-group differences were found in any secondary outcome.Physiotherapy with addition of 5 sessions of ST yielded no additional improvements compared to physiotherapy without strength training in reducing the knee-extension strength deficit at follow-up in patients with a hip fracture. It is debatable whether larger improvements than the observed 8-10% can be expected given that only five exercise sessions, on average, were completed. In fragile patients with a hip fracture in the acute phase, where the ability to participate in functional exercise is compromised, we still consider early strength training a

The Effects of Isokinetic Strength Training on Strength at Different Angular Velocities: a Pilot Study

Directory of Open Access Journals (Sweden)

Tuğba Kocahan

2017-09-01

Conclusion: It was shown that angular velocity is important in isokinetic training, and that training at high angular velocities provides strength increases at lower angular velocities, but would not increase strength at angular velocities above the training level. For this reason, it is thought that in the preparation of an isokinetic strength training protocol, angular velocities need to be taken into account. For any athlete, the force at the angular velocity required in her/his sports branch needs to be considered.

Shear strength of non-shear reinforced concrete elements

DEFF Research Database (Denmark)

Hoang, Cao linh

1997-01-01

is based upon the hypothesis that cracks can be transformed into yield lines, which have lower sliding resistance than yield lines formed in uncracked concrete.Proposals have been made on how the derived standard solutions may be applied to more complicated cases, such as continuous beams, beams......The report deals with the shear strength of statically indeterminate reinforced concrete beams without shear reinforcement. Solutions for a number of beams with different load and support conditions have been derived by means of the crack sliding model developed by Jin- Ping Zhang.This model...

Adsorption of Sr on kaolinite, illite and montmorillonite at high ionic strengths

Energy Technology Data Exchange (ETDEWEB)

Mahoney, J.J.; Langmuir, D. (Colorado School of Mines, Golden (USA). Dept. of Chemistry and Geochemistry)

1991-01-01

Experimental measurements of Sr adsorption onto kaolinite, illite and montmorillonite in up to 4.0 mol/kg NaCl solutions, were modelled with the surface ionization and complexation triple-layer (SIC) model (Davis et al.) to determine if model adjustments were required for high ionic strengths. Improved model fits to the adsorption data were obtained at high ionic strengths, reflecting a lowered sensitivity of the model. A general reduction in Sr adsorption with increasing ionic strength was caused by an increase in the outer layer surface charge, rather than by a drop in the number of available adsorption sites. Sensitivity analysis showed that the range of values of model constants yielding acceptable fits was as large as variations reported in the literature for these constants. The study demonstrates that adsorption will not retard Sr migration in brines, and that it is unnecessary to introduce a Pitzer ion interaction subroutine in the SIC model when considering adsorption at high ionic strengths. (orig.).

Strength Testing in Motor Neuron Diseases.

Science.gov (United States)

Shefner, Jeremy M

2017-01-01

Loss of muscle strength is a cardinal feature of all motor neuron diseases. Functional loss over time, including respiratory dysfunction, inability to ambulate, loss of ability to perform activities of daily living, and others are due, in large part, to decline in strength. Thus, the accurate measurement of limb muscle strength is essential in therapeutic trials to best understand the impact of therapy on vital function. While qualitative strength measurements show declines over time, the lack of reproducibility and linearity of measurement make qualitative techniques inadequate. A variety of quantitative measures have been developed; all have both positive attributes and limitations. However, with careful training and reliability testing, quantitative measures have proven to be reliable and sensitive indicators of both disease progression and the impact of experimental therapy. Quantitative strength measurements have demonstrated potentially important therapeutic effects in both amyotrophic lateral sclerosis and spinobulbar muscular atrophy, and have been shown feasible in children with spinal muscular atrophy. The spectrum of both qualitative and quantitative strength measurements are reviewed and their utility examined in this review.

Strength functions for fragmented doorway states

International Nuclear Information System (INIS)

MacDonald, W.M.

1980-01-01

Coupling a strongly excited ''doorway state'' to weak ''hallway states'' distributes its strength into micro-resonances seen in differential cross sections taken with very good energy resolution. The distribution of strength is shown to be revealed by reduced widths of the K-matrix rather than by the imaginary part of poles of the S-matrix. Different strength functions (SF) constructed by averaging the K-matrix widths are then investigated to determine their dependences on energy and on parameters related to averages of microscopic matrix elements. A new sum rule on the integrated strength of these SF is derived and used to show that different averaging procedures actually distribute the strength differently. Finally, it is shown that the discontinuous summed strength defines spreading parameters for the doorway state only in strong coupling, where it approximates the idefinite integral of the continuous SF of MacDonald-Mekjian-Kerman-De Toledo Piza. A new method of ''parametric continuation'' is used to relate a discontinuous sliding box-average, or a finite sum, of discrete terms to a continous function

High-strength beryllium block

International Nuclear Information System (INIS)

Pinto, N.P.; Keith, G.H.

1977-01-01

Beryllium billets hot isopressed using fine powder of high purity have exceptionally attractive properties; average tensile ultimate, 0.2% offset yield strength and elongation are 590 MPa, 430 MPa and 4.0% respectively. Properties are attributed to the fine grain size (about 4.0 μm average diameter) and the relatively low levels of BeO present as fine, well-dispersed particles. Dynamic properties, e.g., fracture toughness, are similar to those of standard grade, high-purity beryllium. The modulus of beryllium is retained to very high stress levels, and the microyield stress or precision elastic limit is higher than for other grades, including instrument grades. Limited data for billets made from normal-purity fine powders show similar room temperature properties. (author)

Strength Training: For Overall Fitness

Science.gov (United States)

Healthy Lifestyle Fitness Strength training is an important part of an overall fitness program. Here's what strength training can do for ... is a key component of overall health and fitness for everyone. Lean muscle mass naturally diminishes with ...

Strength Assessment of Controlled Low Strength Materials (CLSM) Utilizing Recycled Concrete Aggregate and Waste Paper Sludge Ash

OpenAIRE

Ridzuan, Ahmad Ruslan Mohd; Fauzi, Mohd Azrizal; Ghazali, Ezliana; Arshad, Mohd Fadzil; Fauzi, Mohd Afiq; Mohd Fauzi, Mohd Afiq

2013-01-01

This paper studies the strength development of low-strength material (CLSM) is controlled by using waste paper sludge ash (WPSA) in CLSM mixtures without adding Portland cement. Series of four (4) compounds which is the CLSM containing 5%, 10%, 20% and 30% of waste paper sludge ash (WPSA) as a substitute for Portland cement. CLSM cubes the sizes of 100mm x 100mm x 100mm compressive strength were tested at age 7, 14 and 28days. It was found that this activity contributes to strength developmen...

Experimental knee joint pain during strength training and muscle strength gain in healthy subjects: a randomized controlled trial.

Science.gov (United States)

Sørensen, T J; Langberg, H; Hodges, P W; Bliddal, H; Henriksen, M

2012-01-01

Knee joint pain and reduced quadriceps strength are cardinal symptoms in many knee pathologies. In people with painful knee pathologies, quadriceps exercise reduces pain, improves physical function, and increases muscle strength. A general assumption is that pain compromises muscle function and thus may prevent effective rehabilitation. This study evaluated the effects of experimental knee joint pain during quadriceps strength training on muscle strength gain in healthy individuals. Twenty-seven healthy untrained volunteers participated in a randomized controlled trial of quadriceps strengthening (3 times per week for 8 weeks). Participants were randomized to perform resistance training either during pain induced by injections of painful hypertonic saline (pain group, n = 13) or during a nonpainful control condition with injection of isotonic saline (control group, n = 14) into the infrapatellar fat pad. The primary outcome measure was change in maximal isokinetic muscle strength in knee extension/flexion (60, 120, and 180 degrees/second). The group who exercised with pain had a significantly larger improvement in isokinetic muscle strength at all angular velocities of knee extension compared to the control group. In knee flexion there were improvements in isokinetic muscle strength in both groups with no between-group differences. Experimental knee joint pain improved the training-induced gain in muscle strength following 8 weeks of quadriceps training. It remains to be studied whether knee joint pain has a positive effect on strength gain in patients with knee pathology. Copyright © 2012 by the American College of Rheumatology.

Additively manufactured hierarchical stainless steels with high strength and ductility

Science.gov (United States)

Wang, Y. Morris; Voisin, Thomas; McKeown, Joseph T.; Ye, Jianchao; Calta, Nicholas P.; Li, Zan; Zeng, Zhi; Zhang, Yin; Chen, Wen; Roehling, Tien Tran; Ott, Ryan T.; Santala, Melissa K.; Depond, Philip J.; Matthews, Manyalibo J.; Hamza, Alex V.; Zhu, Ting

2018-01-01

Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength-ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearly six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications.

Correlation between compressive strength and ultrasonic pulse velocity of high strength concrete incorporating chopped basalt fibre

Science.gov (United States)

Shafiq, Nasir; Fadhilnuruddin, Muhd; Elshekh, Ali Elheber Ahmed; Fathi, Ahmed

2015-07-01

Ultrasonic pulse velocity (UPV), is considered as the most important test for non-destructive techniques that are used to evaluate the mechanical characteristics of high strength concrete (HSC). The relationship between the compressive strength of HSC containing chopped basalt fibre stands (CBSF) and UPV was investigated. The concrete specimens were prepared using a different ratio of CBSF as internal strengthening materials. The compressive strength measurements were conducted at the sample ages of 3, 7, 28, 56 and 90 days; whilst, the ultrasonic pulse velocity was measured at 28 days. The result of HSC's compressive strength with the chopped basalt fibre did not show any improvement; instead, it was decreased. The UPV of the chopped basalt fibre reinforced concrete has been found to be less than that of the control mix for each addition ratio of the basalt fibre. A relationship plot is gained between the cube compressive strength for HSC and UPV with various amounts of chopped basalt fibres.

The determining impact of coiling temperature on the microstructure and mechanical properties of a titanium-niobium ultrahigh strength microalloyed steel: Competing effects of precipitation and bainite

Energy Technology Data Exchange (ETDEWEB)

Natarajan, V.V.; Challa, V.S.A. [Laboratory for Excellence in Advanced Steel Research, Materials Science and Engineering Program, Department of Metallurgical, Materials and Biomedical Engineering, 500 W. University Avenue, University of Texas at El Paso, El Paso, TX 79968 (United States); Misra, R.D.K., E-mail: dmisra2@utep.edu [Laboratory for Excellence in Advanced Steel Research, Materials Science and Engineering Program, Department of Metallurgical, Materials and Biomedical Engineering, 500 W. University Avenue, University of Texas at El Paso, El Paso, TX 79968 (United States); Sidorenko, D.M.; Mulholland, M.D.; Manohar, M.; Hartmann, J.E. [ArcelorMittal Global R& D Center, 3001 East Columbus Drive, East Chicago, IN 46312 (United States)

2016-05-17

We elucidate here the influence of coiling temperature on the microstructure and mechanical properties, in an ultrahigh strength titanium-niobium microalloyed steel. The objective was to underscore the impact of coiling temperature on the nature and distribution of microstructural constituents (including different phases, precipitates, and dislocation structure) that significantly contributed to differences in the yield and tensile strength of these steels. Depending on the coiling temperature, the microstructure consisted of either a combination of fine lath-type bainite and polygonal ferrite or polygonal ferrite together with the precipitation of microalloyed carbides of size ~2–10 nm in the matrix and at dislocations. The microstructure of steel coiled at lower temperature predominantly consisted of bainitic ferrite with lower yield strength compared to the steel coiled at higher temperature, and the yield to tensile strength ratio was 0.76. The steel coiled at higher temperature consisted of polygonal ferrite and extensive precipitation of carbides and was characterized by higher yield strength and with yield strength/tensile strength ratio of 0.936. The difference in the tensile strength was insignificant for the two coiling temperatures. The observed microstructure was consistent with the continuous cooling transformation diagram.

Dataset of the relationship between unconfined compressive strength and tensile strength of rock mass

International Nuclear Information System (INIS)

Sugita, Yutaka; Yui, Mikazu

2002-02-01

This report summary the dataset of the relationship between unconfined compressive strength and tensile strength of the rock mass described in supporting report 2; repository design and engineering technology of second progress report (H12 report) on research and development for the geological disposal of HLW in Japan. (author)

Improving Strength-Ductility Balance of High Strength Dual-Phase Steels by Addition of Vanadium

Science.gov (United States)

Gong, Yu; Hua, M.; Uusitalo, J.; DeArdo, A. J.

For galvanized or galvannealed steels to be commercially successful, they must exhibit several attributes: (i) easy and inexpensive processing in the hot mill, cold mill and on the coating line, (ii) high strength with good formability and spot weldability, and (iii) good corrosion resistance, especially after cold forming. For good corrosion resistance, the coating must have sufficient coverage, be of uniform thickness, and most importantly, the coating must survive the cold stamping or forming operation. The purpose of this paper is to present research aiming at improving the steel substrate, such that high strength can be obtained while maintaining good global formability (tensile ductility), local formability (sheared-edge ductility), and good spot weldability. It is well-known that the strength of DP steels is controlled by several factors, including the amount of martensite found in the final microstructure. Recent research has revealed that the amount of austenite formed during intercritical annealing can be strongly influenced by the annealing temperature and the pre-annealing conditions of the hot band (coiling temperature) and cold band (% cold reduction). Current experiments have explored the combination of pre-annealing conditions and four annealing practices to help define the best practice to optimize the strength-formability balance in these higher strength DP steels. The steels used in these experiments contained (i) low carbon content for good spot weldability, (ii) the hardenability additions Mo and Cr for strength, and (iii) V for grain refinement, precipitation hardening and temper resistance. When processed correctly, these steels exhibited UTS levels up to 1000MPa, total elongation to 25%, reduction in area to 45%, and Hole Expansion Ratios to 50%. The results of this program will be presented and discussed.

Hand grip strength

DEFF Research Database (Denmark)

Frederiksen, Henrik; Gaist, David; Petersen, Hans Christian

2002-01-01

in life is a major problem in terms of prevalence, morbidity, functional limitations, and quality of life. It is therefore of interest to find a phenotype reflecting physical functioning which has a relatively high heritability and which can be measured in large samples. Hand grip strength is known......-55%). A powerful design to detect genes associated with a phenotype is obtained using the extreme discordant and concordant sib pairs, of whom 28 and 77 dizygotic twin pairs, respectively, were found in this study. Hence grip strength is a suitable phenotype for identifying genetic variants of importance to mid...

The effect of TiO{sub 2} nanoparticles on water permeability and thermal and mechanical properties of high strength self-compacting concrete

Energy Technology Data Exchange (ETDEWEB)

Nazari, Ali, E-mail: alinazari84@aut.ac.ir [Department of Technical and Engineering Sciences, Islamic Azad University (Saveh Branch), Saveh (Iran, Islamic Republic of); Riahi, Shadi [Department of Technical and Engineering Sciences, Islamic Azad University (Saveh Branch), Saveh (Iran, Islamic Republic of)

2010-12-15

Research highlights: {yields} TiO{sub 2} nanoparticles effects on self-compacting concrete. {yields} Strength assessments. {yields} Water permeability. {yields} Thermal properties. {yields} Pore structure. {yields} Microstructure evaluations. - Abstract: In this work, strength assessments and coefficient of water absorption of high performance self-compacting concrete containing different amounts of TiO{sub 2} nanoparticles have been investigated. The results indicate that the strength and the resistance to water permeability of the specimens are improved by adding TiO{sub 2} nanoparticles in the cement paste up to 4.0 wt%. TiO{sub 2} nanoparticles, as a result of increased crystalline Ca(OH){sub 2} amount especially at the early age of hydration, could accelerate C-S-H gel formation and hence increase the strength of the concrete specimens. In addition, TiO{sub 2} nanoparticles are able to act as nanofillers and recover the pore structure of the specimens by decreasing harmful pores. Several empirical relationships have been presented to predict flexural and split tensile strength of the specimens by means of the corresponding compressive strength at a certain age of curing. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of the peaks related to hydrated products in X-ray diffraction results, all indicate that TiO{sub 2} nanoparticles could improve mechanical and physical properties of the concrete specimens.

Nanostructural hierarchy increases the strength of aluminium alloys.

Science.gov (United States)

Liddicoat, Peter V; Liao, Xiao-Zhou; Zhao, Yonghao; Zhu, Yuntian; Murashkin, Maxim Y; Lavernia, Enrique J; Valiev, Ruslan Z; Ringer, Simon P

2010-09-07

Increasing the strength of metallic alloys while maintaining formability is an interesting challenge for enabling new generations of lightweight structures and technologies. In this paper, we engineer aluminium alloys to contain a hierarchy of nanostructures and possess mechanical properties that expand known performance boundaries-an aerospace-grade 7075 alloy exhibits a yield strength and uniform elongation approaching 1 GPa and 5%, respectively. The nanostructural architecture was observed using novel high-resolution microscopy techniques and comprises a solid solution, free of precipitation, featuring (i) a high density of dislocations, (ii) subnanometre intragranular solute clusters, (iii) two geometries of nanometre-scale intergranular solute structures and (iv) grain sizes tens of nanometres in diameter. Our results demonstrate that this novel architecture offers a design pathway towards a new generation of super-strong materials with new regimes of property-performance space.

Which strengths-based practice? Reconciling strengths-based practice and mandated authority in child protection work.

Science.gov (United States)

Oliver, Carolyn; Charles, Grant

2015-04-01

The recent application of strengths-based practice in child protection settings has been accompanied by evidence of inconsistent implementation and concerns that the approach is incompatible with statutory work. Few studies have moved beyond asking whether child protection workers are implementing strengths-based practice to explore why the approach is enacted as it is. This article describes a mixed methods study using an online survey and interviews to elicit from 225 statutory child protection workers in a large Canadian agency how they applied strengths-based ideas and why they did what they did. The authors found that although strengths-based practice was popular, 70 percent of participants believed that it was not always applicable to child protection work. Participants described five distinct versions of the approach, only one of which was fully congruent with their mandated role. The study suggests that the common conflation of strengths-based and solution-focused approaches ignores important differences in the conceptualization of practitioner authority and leaves practitioners attempting to implement versions ofstrengths-based practice that do not fit statutory child protection work. Only when practitioners choose solution-focused models that support their use of mandated authority is consistent implementation a reasonable expectation.

Enhanced reconstruction of weighted networks from strengths and degrees

International Nuclear Information System (INIS)

Mastrandrea, Rossana; Fagiolo, Giorgio; Squartini, Tiziano; Garlaschelli, Diego

2014-01-01

Network topology plays a key role in many phenomena, from the spreading of diseases to that of financial crises. Whenever the whole structure of a network is unknown, one must resort to reconstruction methods that identify the least biased ensemble of networks consistent with the partial information available. A challenging case, frequently encountered due to privacy issues in the analysis of interbank flows and Big Data, is when there is only local (node-specific) aggregate information available. For binary networks, the relevant ensemble is one where the degree (number of links) of each node is constrained to its observed value. However, for weighted networks the problem is much more complicated. While the naïve approach prescribes to constrain the strengths (total link weights) of all nodes, recent counter-intuitive results suggest that in weighted networks the degrees are often more informative than the strengths. This implies that the reconstruction of weighted networks would be significantly enhanced by the specification of both strengths and degrees, a computationally hard and bias-prone procedure. Here we solve this problem by introducing an analytical and unbiased maximum-entropy method that works in the shortest possible time and does not require the explicit generation of reconstructed samples. We consider several real-world examples and show that, while the strengths alone give poor results, the additional knowledge of the degrees yields accurately reconstructed networks. Information-theoretic criteria rigorously confirm that the degree sequence, as soon as it is non-trivial, is irreducible to the strength sequence. Our results have strong implications for the analysis of motifs and communities and whenever the reconstructed ensemble is required as a null model to detect higher-order patterns

Stress-strain relationship of high-strength steel (HSS) reinforcing bars

Science.gov (United States)

Anggraini, Retno; Tavio, Raka, I. Gede Putu; Agustiar

2018-05-01

The introduction of High-Strength Steel (HSS) reinforcing bars in reinforced concrete members has gained much attention in recent years and led to many advantages such as construction timesaving. It is also more economical since it can reduce the amount of reinforcing steel bars used in concrete members which in turn alleviates the congestion of reinforcement. Up to present, the building codes, e.g. American Concrete Institute (ACI) 318M-14 and Standard National Indonesia (SNI) 2847:2013, still restrict the use of higher-strength steel reinforcing bars for concrete design up to Grade 420 MPa due to the possible suspected brittle behavior of concrete members. This paper evaluates the characteristics of stress-strain relationships of HSS bars if they are comparable to the characteristics of those of Grade 420 MPa. To achieve the objective of the study, a series of steel bars from various grades (420, 550, 650, and 700 MPa) was selected. Tensile tests of these steel samples were conducted under displacement-controlled mode to capture the complete stress-strain curves and particularly the post-yield response of the steel bars. The results indicate that all the steel bars tested had the actual yield strengths greater than the corresponding specified values. The stress-strain curves of HSS reinforcing bars (Grade 550, 650, and 700 MPa) performed slightly different characteristics with those of Grade 420 MPa.

Hip strength assessment using handheld dynamometry is subject to intertester bias when testers are of different sex and strength

DEFF Research Database (Denmark)

Thorborg, K; Bandholm, T; Schick, M

2013-01-01

Handheld dynamometry (HHD) is a promising tool for obtaining reliable hip strength measurements in the clinical setting, but intertester reliability has been questioned, especially in situations where testers exhibit differences in upper-extremity muscle strength (male vs female). The purpose...... of this study was to examine the intertester reliability concerning strength assessments of hip abduction, adduction, external and internal rotation, flexion and extension using HHD, and to test whether systematic differences in test values exist between testers of different upper-extremity strength. Fifty...... healthy individuals (29 women), aged 25 ± 5 years were included. Two physiotherapist students (one female, one male) of different upper-extremity strength performed the measurements. The tester order and strength test order were randomized. Intraclass correlation coefficients were used to quantify...

Personal Strengths and Health Related Quality of Life in Dementia Caregivers from Latin America

Directory of Open Access Journals (Sweden)

Stephen K. Trapp

2015-01-01

Full Text Available The research literature has begun to demonstrate associations between personal strengths and enhanced psychosocial functioning of dementia caregivers, but these relationships have not been examined in the context of dementia caregivers in Latin America. The present study examined whether personal strengths, including resilience, optimism, and sense of coherence, were associated with mental and physical health related quality of life (HRQOL in 130 dementia caregivers in Mexico and Argentina. Structural equation modeling found that the personal strengths collectively accounted for 58.4% of the variance in caregiver mental HRQOL, and resilience, sense of coherence, and optimism each had unique effects. In comparison, the personal strengths together accounted for 8.9% of the variance in caregiver physical HRQOL, and only sense of coherence yielded a unique effect. These results underscore the need to construct and disseminate empirically supported interventions based in part on important personal strengths, particularly sense of coherence, for this underrepresented group.

Personal Strengths and Health Related Quality of Life in Dementia Caregivers from Latin America

Science.gov (United States)

Trapp, Stephen K.; Perrin, Paul B.; Aggarwal, Richa; Peralta, Silvina Victoria; Stolfi, Miriam E.; Morelli, Eliana; Peña Obeso, Leticia Aracely; Arango-Lasprilla, Juan Carlos

2015-01-01

The research literature has begun to demonstrate associations between personal strengths and enhanced psychosocial functioning of dementia caregivers, but these relationships have not been examined in the context of dementia caregivers in Latin America. The present study examined whether personal strengths, including resilience, optimism, and sense of coherence, were associated with mental and physical health related quality of life (HRQOL) in 130 dementia caregivers in Mexico and Argentina. Structural equation modeling found that the personal strengths collectively accounted for 58.4% of the variance in caregiver mental HRQOL, and resilience, sense of coherence, and optimism each had unique effects. In comparison, the personal strengths together accounted for 8.9% of the variance in caregiver physical HRQOL, and only sense of coherence yielded a unique effect. These results underscore the need to construct and disseminate empirically supported interventions based in part on important personal strengths, particularly sense of coherence, for this underrepresented group. PMID:26160998

Imaging Shear Strength Along Subduction Faults

Science.gov (United States)

Bletery, Quentin; Thomas, Amanda M.; Rempel, Alan W.; Hardebeck, Jeanne L.

2017-11-01

Subduction faults accumulate stress during long periods of time and release this stress suddenly, during earthquakes, when it reaches a threshold. This threshold, the shear strength, controls the occurrence and magnitude of earthquakes. We consider a 3-D model to derive an analytical expression for how the shear strength depends on the fault geometry, the convergence obliquity, frictional properties, and the stress field orientation. We then use estimates of these different parameters in Japan to infer the distribution of shear strength along a subduction fault. We show that the 2011 Mw9.0 Tohoku earthquake ruptured a fault portion characterized by unusually small variations in static shear strength. This observation is consistent with the hypothesis that large earthquakes preferentially rupture regions with relatively homogeneous shear strength. With increasing constraints on the different parameters at play, our approach could, in the future, help identify favorable locations for large earthquakes.

Imaging shear strength along subduction faults

Science.gov (United States)

Bletery, Quentin; Thomas, Amanda M.; Rempel, Alan W.; Hardebeck, Jeanne L.

2017-01-01

Subduction faults accumulate stress during long periods of time and release this stress suddenly, during earthquakes, when it reaches a threshold. This threshold, the shear strength, controls the occurrence and magnitude of earthquakes. We consider a 3-D model to derive an analytical expression for how the shear strength depends on the fault geometry, the convergence obliquity, frictional properties, and the stress field orientation. We then use estimates of these different parameters in Japan to infer the distribution of shear strength along a subduction fault. We show that the 2011 Mw9.0 Tohoku earthquake ruptured a fault portion characterized by unusually small variations in static shear strength. This observation is consistent with the hypothesis that large earthquakes preferentially rupture regions with relatively homogeneous shear strength. With increasing constraints on the different parameters at play, our approach could, in the future, help identify favorable locations for large earthquakes.

Properties of Galvanized and Galvannealed Advanced High Strength Hot Rolled Steels

Energy Technology Data Exchange (ETDEWEB)

V.Y. Guertsman; E. Essadiqi; S. Dionne; O. Dremmailova; R. Bouchard; B. Voyzelle; J. McDermid; R. Fourmentin

2008-04-01

The objectives of the project were (i) to develop the coating process information to achieve good quality coatings on 3 advanced high strength hot rolled steels while retaining target mechanical properties, (ii) to obtain precise knowledge of the behavior of these steels in the various forming operations and (iii) to establish accurate user property data in the coated conditions. Three steel substrates (HSLA, DP, TRIP) with compositions providing yield strengths in the range of 400-620 MPa were selected. Only HSLA steel was found to be suitable for galnaizing and galvannealing in the hot rolled condition.

Effect of hot extrusion, other constituents, and temperature on the strength and fracture of polycrystalline MgO

Energy Technology Data Exchange (ETDEWEB)

Rice, R.W. (W.R. Grace and Co.-Conn, Columbia, MD (United States))

1993-12-01

Improved agreement was confirmed between the Petch intercept and single-crystal yield stresses at 22 C. Hot-extruded MgO crystal specimens stressed parallel with the resultant axial texture (1) gave the highest and least-scattered strength-grain size results at 22 C, (2) showed direct fractographic evidence of microplastic initiated fracture at 22 C and showed macroscopic yield at 1,315 and especially 1,540 C, and (3) fractured entirely via transgranular cleavage, except for intergranular failure initiation from one or a few grain boundary surfaces exposed on the subsequent fracture surface, mainly at 1,540 C. Hot-extruded, hot-pressed MgO billets gave comparable strength when fracture initiated transgranularly, but lower strength when fracture initiated from one or especially a few grain boundary surfaces exposed on the fracture. The extent and frequency of such boundary fracture increased with test temperature. While oxide additions of [<=] 5% or impurities in hot-pressed or hot-extruded MgO can make limited strength increases at larger grain sizes, those having limited solubility can limit strength at finer grain sizes, as can coarser surface finish. Overall, MgO strength is seen as a balance between flaw and microplastic controlled failure, with several parameters shifting the balance.

Oscillator strengths for neutral technetium

International Nuclear Information System (INIS)

Garstang, R.H.

1981-01-01

Oscillator strengths have been calculated for most of the spectral lines of TcI which are of interest in the study of stars of spectral type S. Oscillator strengths have been computed for the corresponding transitions in MnI as a partial check of the technetium calculations

Rock strength under explosive loading

International Nuclear Information System (INIS)

Rimer, N.; Proffer, W.

1993-01-01

This presentation emphasizes the importance of a detailed description of the nonlinear deviatoric (strength) response of the surrounding rock in the numerical simulation of underground nuclear explosion phenomenology to the late times needed for test ban monitoring applications. We will show how numerical simulations which match ground motion measurements in volcanic tuffs and in granite use the strength values obtained from laboratory measurements on small core samples of these rocks but also require much lower strength values after the ground motion has interacted with the rock. The underlying physical mechanisms for the implied strength reduction are not yet well understood, and in fact may depend on the particular rock type. However, constitutive models for shock damage and/or effective stress have been used successfully at S-Cubed in both the Geophysics Program (primarily for DARPA) and the Containment Support Program (for DNA) to simulate late time ground motions measured at NTS in many different rock types

Polynomial expansions and transition strengths

International Nuclear Information System (INIS)

Draayer, J.P.

1980-01-01

The subject is statistical spectroscopy applied to determining strengths and strength sums of excitation processes in nuclei. The focus will be on a ds-shell isoscalar E2 study with detailed shell-model results providing the standard for comparison; similar results are available for isovector E2 and M1 and E4 transitions as well as for single-particle transfer and ν +- decay. The present study is intended to serve as a tutorial for applications where shell-model calculations are not feasible. The problem is posed and a schematic theory for strengths and sums is presented. The theory is extended to include the effect of correlations between H, the system Hamiltonian, and theta, the excitation operator. Associated with correlation measures is a geometry that can be used to anticipate the goodness of a symmetry. This is illustrated for pseudo SU(3) in the fp-shell. Some conclusions about fluctuations and collectivity that one can deduce from the statistical results for strengths are presented

Experimental and simulated strength of spot welds

DEFF Research Database (Denmark)

Nielsen, Chris Valentin; Bennedbæk, Rune A.K.; Larsen, Morten B.

2014-01-01

Weld strength testing of single spots in DP600 steel is presented for the three typical testing procedures, i.e. tensile-shear, cross-tension and peel testing. Spot welds are performed at two sets of welding parameters and strength testing under these conditions is presented by load......-elongation curves revealing the maximum load and the elongation at break. Welding and strength testing is simulated by SORPAS® 3D, which allows the two processes to be prepared in a combined simulation, such that the simulated welding properties are naturally applied to the simulation of strength testing. Besides...... the size and shape of the weld nugget, these properties include the new strength of the material in the weld and the heat affected zone based on the predicted hardness resulting from microstructural phase changes simulated during cooling of the weld before strength testing. Comparisons between overall...

The reliabilty of isokinetic strength measurement

OpenAIRE

Kadlec, Miroslav

2011-01-01

Title: Reliability of isometric and isokinetic strength testing in the knee flexion and extension Objectives: To compare the reliability of isometric and isokinetic testing of the knee strength in flexion and extension Methods: I used intraclass correlation coefficient and Pearson's correlation coefficient. Results: I have discovered that the reliability measured on isokinetic and isometric dynamometer is high. Furthermore the reliability of the maximum strength measurement was higher with-us...

Compressive strength, flexural strength and water absorption of concrete containing palm oil kernel shell

Science.gov (United States)

Noor, Nurazuwa Md; Xiang-ONG, Jun; Noh, Hamidun Mohd; Hamid, Noor Azlina Abdul; Kuzaiman, Salsabila; Ali, Adiwijaya

2017-11-01

Effect of inclusion of palm oil kernel shell (PKS) and palm oil fibre (POF) in concrete was investigated on the compressive strength and flexural strength. In addition, investigation of palm oil kernel shell on concrete water absorption was also conducted. Total of 48 concrete cubes and 24 concrete prisms with the size of 100mm × 100mm × 100mm and 100mm × 100mm × 500mm were prepared, respectively. Four (4) series of concrete mix consists of coarse aggregate was replaced by 0%, 25%, 50% and 75% palm kernel shell and each series were divided into two (2) main group. The first group is without POF, while the second group was mixed with the 5cm length of 0.25% of the POF volume fraction. All specimen were tested after 7 and 28 days of water curing for a compression test, and flexural test at 28 days of curing period. Water absorption test was conducted on concrete cube age 28 days. The results showed that the replacement of PKS achieves lower compressive and flexural strength in comparison with conventional concrete. However, the 25% replacement of PKS concrete showed acceptable compressive strength which within the range of requirement for structural concrete. Meanwhile, the POF which should act as matrix reinforcement showed no enhancement in flexural strength due to the balling effect in concrete. As expected, water absorption was increasing with the increasing of PKS in the concrete cause by the porous characteristics of PKS

COLLISION STRENGTHS AND EFFECTIVE COLLISION STRENGTHS FOR TRANSITIONS WITHIN THE GROUND-STATE CONFIGURATION OF S III

Energy Technology Data Exchange (ETDEWEB)

Hudson, C. E.; Ramsbottom, C. A.; Scott, M. P., E-mail: c.hudson@qub.ac.uk, E-mail: c.ramsbottom@qub.ac.uk, E-mail: p.scott@qub.ac.uk [Department of Applied Maths and Theoretical Physics, The Queen' s University of Belfast, Belfast BT7 1NN (United Kingdom)

2012-05-01

We have carried out a 29-state R-matrix calculation in order to calculate collision strengths and effective collision strengths for the electron impact excitation of S III. The recently developed parallel RMATRX II suite of codes have been used, which perform the calculation in intermediate coupling. Collision strengths have been generated over an electron energy range of 0-12 Ryd, and effective collision strength data have been calculated from these at electron temperatures in the range 1000-100,000 K. Results are here presented for the fine-structure transitions between the ground-state configurations of 3s {sup 2}3p {sup 23} P{sub 0,1,2}, {sup 1}D{sub 2}, and {sup 1} S{sub 0}, and the values given resolve a discrepancy between two previous R-matrix calculations.

Effect of surface treatments on the bond strengths of facing composite resins to zirconia copings.

Science.gov (United States)

Tsumita, M; Kokubo, Y; Kano, T

2012-09-01

The present study evaluated and compared the bond strength between zirconia and facing composite resin using different surface conditioning methods before and after thermocycling. Four primers, three opaque resins, and two facing composite resins were used, and 10 surface treatment procedures were conducted. The bond strength was measured before and after 4,000 cycles of thermocycling. The mean values of each group were statistically analyzed using one-way analysis of variance (ANOVA). The bond strengths of facing composite resins to zirconia after various treatments varied depending on the primers, opaque resins, body resins, and thermocycling. The application of primers and opaque resins to the zirconia surface after sandblasting is expected to yield strong bond strength of the facing composite resin (Estenia CG&B) even after thermocycling.

Strength of Ship Plates under Combined Loading

DEFF Research Database (Denmark)

Cui, W.; Wang, Y.; Pedersen, Preben Terndrup

2002-01-01

Strength of ship plates plays a significant role in the ultimate strength analysis of ship structures. In recent years several authors have proposed simplified analytical methods to calculate the ultimate strength of unstiffened plates. The majority of these investigations deal with plates subjec...

Effectiveness of Traditional Strength vs. Power Training on Muscle Strength, Power and Speed with Youth: A Systematic Review and Meta-Analysis

Science.gov (United States)

Behm, David G.; Young, James D.; Whitten, Joseph H. D.; Reid, Jonathan C.; Quigley, Patrick J.; Low, Jonathan; Li, Yimeng; Lima, Camila D.; Hodgson, Daniel D.; Chaouachi, Anis; Prieske, Olaf; Granacher, Urs

2017-01-01

Numerous national associations and multiple reviews have documented the safety and efficacy of strength training for children and adolescents. The literature highlights the significant training-induced increases in strength associated with youth strength training. However, the effectiveness of youth strength training programs to improve power measures is not as clear. This discrepancy may be related to training and testing specificity. Most prior youth strength training programs emphasized lower intensity resistance with relatively slow movements. Since power activities typically involve higher intensity, explosive-like contractions with higher angular velocities (e.g., plyometrics), there is a conflict between the training medium and testing measures. This meta-analysis compared strength (e.g., training with resistance or body mass) and power training programs (e.g., plyometric training) on proxies of muscle strength, power, and speed. A systematic literature search using a Boolean Search Strategy was conducted in the electronic databases PubMed, SPORT Discus, Web of Science, and Google Scholar and revealed 652 hits. After perusal of title, abstract, and full text, 107 studies were eligible for inclusion in this systematic review and meta-analysis. The meta-analysis showed small to moderate magnitude changes for training specificity with jump measures. In other words, power training was more effective than strength training for improving youth jump height. For sprint measures, strength training was more effective than power training with youth. Furthermore, strength training exhibited consistently large magnitude changes to lower body strength measures, which contrasted with the generally trivial, small and moderate magnitude training improvements of power training upon lower body strength, sprint and jump measures, respectively. Maturity related inadequacies in eccentric strength and balance might influence the lack of training specificity with the unilateral

Effectiveness of Traditional Strength vs. Power Training on Muscle Strength, Power and Speed with Youth: A Systematic Review and Meta-Analysis

Directory of Open Access Journals (Sweden)

David G. Behm

2017-06-01

Full Text Available Numerous national associations and multiple reviews have documented the safety and efficacy of strength training for children and adolescents. The literature highlights the significant training-induced increases in strength associated with youth strength training. However, the effectiveness of youth strength training programs to improve power measures is not as clear. This discrepancy may be related to training and testing specificity. Most prior youth strength training programs emphasized lower intensity resistance with relatively slow movements. Since power activities typically involve higher intensity, explosive-like contractions with higher angular velocities (e.g., plyometrics, there is a conflict between the training medium and testing measures. This meta-analysis compared strength (e.g., training with resistance or body mass and power training programs (e.g., plyometric training on proxies of muscle strength, power, and speed. A systematic literature search using a Boolean Search Strategy was conducted in the electronic databases PubMed, SPORT Discus, Web of Science, and Google Scholar and revealed 652 hits. After perusal of title, abstract, and full text, 107 studies were eligible for inclusion in this systematic review and meta-analysis. The meta-analysis showed small to moderate magnitude changes for training specificity with jump measures. In other words, power training was more effective than strength training for improving youth jump height. For sprint measures, strength training was more effective than power training with youth. Furthermore, strength training exhibited consistently large magnitude changes to lower body strength measures, which contrasted with the generally trivial, small and moderate magnitude training improvements of power training upon lower body strength, sprint and jump measures, respectively. Maturity related inadequacies in eccentric strength and balance might influence the lack of training specificity with

Prediction of concrete strength in massive structures

International Nuclear Information System (INIS)

Sakamoto, T.; Makino, H.; Nakane, S.; Kawaguchi, T.; Ohike, T.

1989-01-01

Reinforced concrete structures of a nuclear power plant are mostly of mass concrete with cross-sectional dimensions larger than 1.0 m. The temperature of concrete inside after placement rises due to heat of hydration of cement. It is well known that concrete strengths of mass concrete structure subjected to such temperature hysteresis are generally not equal to strengths of cylinders subjected to standard curing. In order to construct a mass concrete structure of high reliability in which the specified concrete strength is satisfied by the specified age, it is necessary to have a thorough understanding of the strength gain property of concrete in the structure and its relationships with the water-cement ratio of the mix, strength of standard-cured cylinders and the internal temperature hysteresis. This report describes the result of studies on methods of controlling concrete strength in actual construction projects

Compressive Strength of Compacted Clay-Sand Mixes

Directory of Open Access Journals (Sweden)

Faseel Suleman Khan

2014-01-01

Full Text Available The use of sand to improve the strength of natural clays provides a viable alternative for civil infrastructure construction involving earthwork. The main objective of this note was to investigate the compressive strength of compacted clay-sand mixes. A natural clay of high plasticity was mixed with 20% and 40% sand (SP and their compaction and strength properties were determined. Results indicated that the investigated materials exhibited a brittle behaviour on the dry side of optimum and a ductile behaviour on the wet side of optimum. For each material, the compressive strength increased with an increase in density following a power law function. Conversely, the compressive strength increased with decreasing water content of the material following a similar function. Finally, the compressive strength decreased with an increase in sand content because of increased material heterogeneity and loss of sand grains from the sides during shearing.

Fatigue Life of High-Strength Steel Offshore Tubular Joints

DEFF Research Database (Denmark)

Petersen, Rasmus Ingomar; Agerskov, Henning; Lopez Martinez, Luis

1996-01-01

In the present investigation, the fatigue life of tubular joints in offshore steel structures is studied. Two test series on full-scale tubular joints have been carried through. One series was on joints in conventional offshore structural steel, and the other series was on joints in high-strength......In the present investigation, the fatigue life of tubular joints in offshore steel structures is studied. Two test series on full-scale tubular joints have been carried through. One series was on joints in conventional offshore structural steel, and the other series was on joints in high......-strength steel with a yield stress of 820-830 MPa and with high weldability and toughness properties. The test specimens of both series had the same geometry. The present report concentrates on the results obtained in the investigation on the high-strength steel tubular joints.The test specimens were fabricated...... from Ø 324-610 mm tubes, and the joints were loaded in in-plane bending. Both fatigue tests under constant amplitude loading and tests with a stochastic loading that is realistic in relation to offshore structures, are included in the investigation.A comparison between constant amplitude and variable...

CADDIS Volume 2. Sources, Stressors and Responses: Ionic Strength

Science.gov (United States)

Introduction to the ionic strength module, when to list ionic strength as a candidate cause, ways to measure ionic strength, simple and detailed conceptual diagrams for ionic strength, ionic strength module references and literature reviews.

Behaviour and strength assessment of masonry prisms

Directory of Open Access Journals (Sweden)

Nassif Nazeer Thaickavil

2018-06-01

Full Text Available This is a case study presenting the cracking behavior and assessment of the compressive strength of masonry prisms. The compressive strength of masonry was determined by performing laboratory tests on 192 masonry prism specimens corresponding to 3 specimens each in 64 groups. The variables considered in the experimental program are type of brick, strength of masonry and height-to-thickness (h/t ratio of the prism specimen. Pressed earth bricks and burnt clay bricks were used for the preparation of masonry prisms. A mathematical model is also proposed for the estimation of compressive strength of masonry prisms by performing a statistical multiple regression analysis on 232 data sets, which includes 64 test data from the present study and 168 test data published in the literature. The model was developed based on the regression analysis of test data of prisms made of a variety of masonry units namely clay bricks, pressed earth bricks, concrete blocks, calcium silicate bricks, stone blocks, perforated bricks and soft mud bricks. The proposed model not only accounts for the wide ranges of compressive strengths of masonry unit and mortar, but also accounts for the influence of volume fractions of masonry unit and mortar in addition to the height-to-thickness ratio. The predicted compressive strength of prisms using the proposed model is compared with 14 models available in published literature. The predicted strength was found to be in good agreement with the corresponding experimental data. Keywords: Prism strength, Stack bonded masonry, Running bonded masonry, Masonry unit strength, Cracking

The German Version of the Strengths Use Scale: The Relation of Using Individual Strengths and Well-being

Directory of Open Access Journals (Sweden)

Alexandra Huber

2017-04-01

Full Text Available Theoretical perspectives in positive psychology have considered the possession and use of strengths equally but in applied research more studies focused on having them, probably due to the absence of psychometrically adequate scales. Therefore, the aim of this study was to assess the psychometric characteristics of the German language version of the Strengths Use Scale (SUS and to explore relationships between strengths use and several indicator measures of well-being: the presence of positive and the absence of negative affect, self-esteem as identity aspect, vitality as self-regulatory resource, and stress for capturing the evaluation of difficulties and obstacles impinging on well-being. The original English version of the SUS was translated following recommended independent forward-backward translation techniques. Exploratory and confirmatory factor analyses were conducted, including a German-speaking convenience sample of university students (N = 374. Additionally, the relations of strengths use and well-being indicators were analyzed. Factorial validity revealed a single-factor structure of the German version of the SUS, explaining 58.4% variance (factor loadings: 0.58 to 0.86, approving the scale’s design and showing high internal consistency (Cronbach’s α 0.95. The hypothesized positive relationships of strengths use with positive affect, self-esteem, and vitality were confirmed as well as the negative relationships with negative affect and stress. The German version of the SUS is psychometrically sound and data indicate that individual strengths use and well-being related measures interact. The instrument can be recommended for future research questions such as if and how the promotion of applying individual strengths during education enhances levels of well-being, or how the implementation of strengths use in job-design guidelines or working conditions can result in higher levels of well-being or healthiness.

Strength of ship plates under combined loading

DEFF Research Database (Denmark)

Cui, Weiching; Wang, Yongjun; Pedersen, Preben Terndrup

2000-01-01

Strength of ship plates plays a significant role for the ultimate strength analysis of ship structures. In recent years several authors have proposed simplified methods to calculate the ultimate strength of unstiffened plates. The majority of these investigations deal with plates subjected to lon...

Relationship between the edgewise compression strength of ...

African Journals Online (AJOL)

The results of this study were used to determine the linear regression constants in the Maltenfort model by correlating the measured board edgewise compression strength (ECT) with the predicted strength, using the paper components' compression strengths, measured with the short-span compression test (SCT) and the ...

Elastic stability and the limit of strength

International Nuclear Information System (INIS)

Morris Jr., J.W.; Krenn, C.R.; Roundy, D.; Cohen, Marvin L.

2002-01-01

The upper limit of strength (the ''theoretical strength'') has been an active subject of research and speculation for the better part of a century. The subject has recently become important, for two reasons. First, given recent advances in ab initio techniques and computing machines, the limits of strength can be calculated with considerable accuracy, making this one of the very few problems in mechanical behavior that can actually be solved. Second, given recent advances in materials engineering, the limits of strength are being approached in some systems, such as hardened or defect-free films, and their relevance is becoming recognized in others. The present paper discusses some interesting results from recent research on the limits of strength, with an intermixture of speculations based on those results. Topics include the inherent nature of {100} cleavage and ''pencil slip'' in bcc metals, the inherent ductility of fcc metals, the anomalous properties of Al, and the possibility of measuring ideal strength with nanoindentation

Redox Buffer Strength

Science.gov (United States)

de Levie, Robert

1999-04-01

The proper functioning of enzymes in bodily fluids requires that the pH be maintained within rather narrow limits. The first line of defense against large pH fluctuations in such fluids is the passive control provided by the presence of pH buffers. The ability of pH buffers to stabilize the pH is indicated by the buffer value b introduced in 1922 by van Slyke. It is equally important for many enzymes that the redox potential is kept within a narrow range. In that case, stability of the potential is most readily achieved with a redox buffer. In this communication we define the redox buffer strength by analogy with acid-base buffer strength.

Self-perceived strengths among people who are homeless

OpenAIRE

Tweed, Roger G.; Biswas-Diener, Robert; Lehman, Darrin R.

2012-01-01

This study examined self-perceived strengths among 116 people who were homeless. Those who had experienced a longer period of current homelessness tended to report fewer personal strengths (r = −0.23). Nonetheless, in spite of their marginalized position in society, the vast majority of participants (114 out of 116) perceived personal strengths. A prior diagnosis with mental illness was not associated with the number of strengths reported, but self-perception of strengths was associated with ...

Relationship between tongue strength, lip strength, and nutrition-related sarcopenia in older rehabilitation inpatients: a cross-sectional study

Directory of Open Access Journals (Sweden)

Sakai K

2017-08-01

Full Text Available Kotomi Sakai,1,2 Enri Nakayama,2 Haruka Tohara,3 Keiji Kodama,4 Takahiro Takehisa,5 Yozo Takehisa,6 Koichiro Ueda2 1Department of Rehabilitation Medicine, Setagaya Memorial Hospital, 2Department of Dysphagia Rehabilitation, Nihon University School of Dentistry, 3Gerodontology and Oral Rehabilitation, Department of Gerontology and Gerodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 4Department of Internal Medicine, 5Department of Orthopaedic Surgery, Setagaya Memorial Hospital, Tokyo, 6Department of Internal Medicine, Hakuai Memorial Hospital, Tokushima, Japan Objective: The objective of this study was to clarify the relationship between tongue strength, lip strength, and nutrition-related sarcopenia (NRS.Patients and methods: A total of 201 older inpatients aged ≥65 years (70 men, median age: 84 years, interquartile range: 79–89 years consecutively admitted for rehabilitation were included in this cross-sectional study. The main factors evaluated were the presence of NRS diagnosed by malnutrition using the Mini-Nutrition Assessment – Short Form, sarcopenia based on the criteria of the Asian Working Group for Sarcopenia, tongue strength, and lip strength. Other factors such as age, sex, comorbidity, physical function, cognitive function, and oral intake level were also assessed.Results: In all, 78 (38.8% patients were allocated to the NRS group, and 123 (61.2% patients were allocated to the non-NRS group. The median tongue strength and lip strength (interquartile range were significantly lower in the NRS group (tongue: 22.9 kPa [17.7–27.7 kPa] and lip: 7.2 N [5.6–9.8 N] compared with the non-NRS group (tongue: 29.7 kPa [24.8–35.1 kPa] and lip: 9.9 N [8.4–12.3 N], P<0.001 for both. Multivariable logistic regression analysis showed that NRS was independently associated with tongue strength (odds ratio [OR] =0.93, 95% confidence interval [CI] 0.87–0.98, P=0.012 and lip

Loading Conditions and Longitudinal Strength

DEFF Research Database (Denmark)

Sørensen, Herman

1995-01-01

Methods for the calculation of the lightweight of the ship.Loading conditions satisfying draught, trim and intact stability requirements and analysis of the corresponding stillwater longitudinal strength.......Methods for the calculation of the lightweight of the ship.Loading conditions satisfying draught, trim and intact stability requirements and analysis of the corresponding stillwater longitudinal strength....

Testosterone Replacement, Muscle Strength, and Physical Function

Directory of Open Access Journals (Sweden)

You-Seon Nam

2018-05-01

Full Text Available Muscle strength and physical function decrease in older men, as do testosterone levels. Nonetheless, the effects of testosterone replacement therapy on muscle strength and physical function remain inconclusive and equivocal. We conducted a rapid systematic review, the results of which showed that testosterone replacement does not affect muscle strength (measured by hand grip strength and leg muscle strength, although it may increase physical function (measured by the 6-minute walk test, Physical Activity Scale for the Elderly score, and other physical performance tests. However, most of the studies were conducted in the United States or Europe and did not include participants from Asian or other ethnic backgrounds; therefore, further studies are needed to evaluate the effects of testosterone replacement in a broader population.

Strength capability while kneeling.

Science.gov (United States)

Haslegrave, C M; Tracy, M F; Corlett, E N

1997-12-01

Work sometimes has to be carried out kneeling, particularly where jobs are performed in confined spaces as is common for miners, aircraft baggage handlers and maintenance workers. In order to assess the risks in performing forceful tasks under such conditions, data is needed on strength capabilities of kneeling subjects. A study was undertaken to measure isometric strength in single-handed exertions for male subjects and to investigate the effects on this of task layout factors (direction of force exertion, reach distance, height of the workpiece and orientation relative to the subject's sagittal plane). The data has been tabulated to show the degree to which strength may be reduced in different situations and analysis of the task factors showed their influence to be complex with direction of exertion and reach distance having the greatest effect. The results also suggest that exertions are weaker when subjects are kneeling on two knees than when kneeling on one knee, although this needs to be confirmed by direct experimental comparison.

Burrowing as a novel voluntary strength training method for mice: A comparison of various voluntary strength or resistance exercise methods.

Science.gov (United States)

Roemers, P; Mazzola, P N; De Deyn, P P; Bossers, W J; van Heuvelen, M J G; van der Zee, E A

2018-04-15

Voluntary strength training methods for rodents are necessary to investigate the effects of strength training on cognition and the brain. However, few voluntary methods are available. The current study tested functional and muscular effects of two novel voluntary strength training methods, burrowing (digging a substrate out of a tube) and unloaded tower climbing, in male C57Bl6 mice. To compare these two novel methods with existing exercise methods, resistance running and (non-resistance) running were included. Motor coordination, grip strength and muscle fatigue were measured at baseline, halfway through and near the end of a fourteen week exercise intervention. Endurance was measured by an incremental treadmill test after twelve weeks. Both burrowing and resistance running improved forelimb grip strength as compared to controls. Running and resistance running increased endurance in the treadmill test and improved motor skills as measured by the balance beam test. Post-mortem tissue analyses revealed that running and resistance running induced Soleus muscle hypertrophy and reduced epididymal fat mass. Tower climbing elicited no functional or muscular changes. As a voluntary strength exercise method, burrowing avoids the confounding effects of stress and positive reinforcers elicited in forced strength exercise methods. Compared to voluntary resistance running, burrowing likely reduces the contribution of aerobic exercise components. Burrowing qualifies as a suitable voluntary strength training method in mice. Furthermore, resistance running shares features of strength training and endurance (aerobic) exercise and should be considered a multi-modal aerobic-strength exercise method in mice. Copyright © 2017 Elsevier B.V. All rights reserved.

Experimental and Numerical Investigations on Strength and Deformation Behavior of Cataclastic Sandstone

Science.gov (United States)

Zhang, Y.; Shao, J. F.; Xu, W. Y.; Zhao, H. B.; Wang, W.

2015-05-01

This work is devoted to characterization of the deformation and strength properties of cataclastic sandstones. Before conducting mechanical tests, the physical properties were first examined. These sandstones are characterized by a loose damaged microstructure and poorly cemented contacts. Then, a series of mechanical tests including hydrostatic, uniaxial, and triaxial compression tests were performed to study the mechanical strength and deformation of the sandstones. The results obtained show nonlinear stress-strain responses. The initial microcracks are closed at hydrostatic stress of 2.6 MPa, and the uniaxial compressive strength is about 0.98 MPa. Under triaxial compression, there is a clear transition from volumetric compressibility to dilatancy and a strong dependency on confining pressure. Based on the experimental evidence, an elastoplastic model is proposed using a linear yield function and a nonassociated plastic potential. There is good agreement between numerical results and experimental data.

Self-perceived strengths among people who are homeless.

Science.gov (United States)

Tweed, Roger G; Biswas-Diener, Robert; Lehman, Darrin R

2012-11-01

This study examined self-perceived strengths among 116 people who were homeless. Those who had experienced a longer period of current homelessness tended to report fewer personal strengths (r = -0.23). Nonetheless, in spite of their marginalized position in society, the vast majority of participants (114 out of 116) perceived personal strengths. A prior diagnosis with mental illness was not associated with the number of strengths reported, but self-perception of strengths was associated with altruistic orientation. The Values in Action (VIA) taxonomy of character strengths captured many of the responses generated by this population. The most frequently mentioned character categories included social intelligence, kindness, persistence, authenticity and humour. The most frequently mentioned other strengths included personal skills (e.g. music, sports), job skills, intelligence and education. The results have relevance for efforts to build self-perceptions that facilitate escape from homelessness.

Effects of a low-intensity strength-training program on knee-extensor strength and functional ability of frail older people

NARCIS (Netherlands)

Westhoff, M.H.; Stemmerik, L.; Boshuizen, H.C.

2000-01-01

This study's purpose was to investigate whether a 10-week low-intensity strength-training program could improve strength of the knee extensors and functional ability. Participants 65 years and older with low knee-extensor muscle strength were randomized into an exercise (n = 11) and a control group

Development of strength-hardness relationships in additively manufactured titanium alloys

Energy Technology Data Exchange (ETDEWEB)

Keist, Jayme S., E-mail: keist@psu.edu; Palmer, Todd A., E-mail: tap103@psu.edu

2017-05-02

A major concern for additively manufactured (AM) Ti-6Al-4V components is how AM processing parameters and post-process heat treatments impact the resulting mechanical behavior. The applicability of using microhardness measurements as a predictive tool for yield and tensile strengths of AM Ti-6Al-4V would provide a rapid and useful screening mechanism for ensuring that properties meet requirements in complex geometries. However, microhardness measurements on Ti-6Al-4V exhibit high levels of data variability due to the orientational impact of the α phase. In order to overcome this variability in hardness measurements, a methodology for aggregating microhardness data in individual builds has been developed and validated. By compiling mean microhardness values from various AM components produced by electron beam based directed energy deposition (DED), laser based DED, and laser based powder bed fusion (PBF) processes in the as-deposited and post-process heat treated conditions, strong linear correlations between strength and hardness can be developed in AM materials having a lamellar α+β microstructure. With the addition of strain hardening and α phase orientation contributions to the mean microhardness measurement, the strength-hardness correlations of AM Ti-6Al-4V followed empirically derived models, opening the possibility of using these models to predict strengths from AM components regardless of the AM process or post-process state.

Criterion-Related Validity of a Simple Muscle Strength Test to Assess Whole Body Muscle Strength in Chinese Children Aged 10 to 12 Years.

Science.gov (United States)

Yin, Liqin; Tang, Changfa; Tao, Xia

2018-01-01

To study the criterion-related validity of simple muscle strength test (SMST) indicators and assess whole body muscle strength in Chinese children aged 10 to 12 years old. Two hundred and forty children were equally divided into four groups in different genders and residences. The SMST indicators (hand-grip, knee bent push-up, back muscle strength, sit-up, leg muscle strength, and standing long jump) were tested. We set up the total level of the whole-body muscle strength ( F total ) through testing isokinetic muscle strength of the six joints' flexion and extension movements. Pearson correlation analyses were used to analyze the correlation between the SMST indicators and the F total . (1) Leg muscle strength and back muscle strength demonstrated the highest validity scores. Sit-ups, hand grip, and standing long jump demonstrated the lowest validity scores. (2) Leg muscle strength had the highest validity for males, but back muscle strength had the highest validity for females. Back muscle strength and leg muscle strength can give the highest validity of assessing whole body muscle strength, and also has higher validity in both the urban and rural children. For urban children, but not rural, the knee bent push-up also has a high validity indicator.

Criterion-Related Validity of a Simple Muscle Strength Test to Assess Whole Body Muscle Strength in Chinese Children Aged 10 to 12 Years

Directory of Open Access Journals (Sweden)

Liqin Yin

2018-01-01

Full Text Available Objective. To study the criterion-related validity of simple muscle strength test (SMST indicators and assess whole body muscle strength in Chinese children aged 10 to 12 years old. Methods. Two hundred and forty children were equally divided into four groups in different genders and residences. The SMST indicators (hand-grip, knee bent push-up, back muscle strength, sit-up, leg muscle strength, and standing long jump were tested. We set up the total level of the whole-body muscle strength (Ftotal through testing isokinetic muscle strength of the six joints’ flexion and extension movements. Pearson correlation analyses were used to analyze the correlation between the SMST indicators and the Ftotal. Results. (1 Leg muscle strength and back muscle strength demonstrated the highest validity scores. Sit-ups, hand grip, and standing long jump demonstrated the lowest validity scores. (2 Leg muscle strength had the highest validity for males, but back muscle strength had the highest validity for females. Conclusions. Back muscle strength and leg muscle strength can give the highest validity of assessing whole body muscle strength, and also has higher validity in both the urban and rural children. For urban children, but not rural, the knee bent push-up also has a high validity indicator.

Tensile properties of machine strength graded timber for glued laminated timber

DEFF Research Database (Denmark)

Boström, Lars; Hoffmeyer, Preben; Solli, Kjell-Helge

1999-01-01

Special setting values based on tensile properties of Norway spruce are established for four different strength grading machines. The machines included are Computermatic, Cook-Bolinder, Ersson and Dynagrade.The study shows that the yield of timber to be used in tension, such as laminations...

Development of LTCC Materials with High Mechanical Strength

International Nuclear Information System (INIS)

Kawai, Shinya; Nishiura, Sousuke; Terashi, Yoshitake; Furuse, Tatsuji

2011-01-01

We have developed LTCC materials suitable for substrates of RF modules used in mobile phone. LTCC can provide excellent solutions to requirements of RF modules, such as down-sizing, embedded elements and high performance. It is also important that LTCC material has high mechanical strength to reduce risk of fracture by mechanical impact. We have established a method of material design for high mechanical strength. There are two successive steps in the concept to achieve high mechanical strength. The first step is to improve mechanical strength by increasing the Young's modulus, and the second step is either further improvement through the Young's modulus or enhancement of the fracture energy. The developed material, so called high-strength LTCC, thus possesses mechanical strength of 400MPa, which is twice as strong as conventional material whose mechanical strength is approximately 200MPa in typical. As a result, high-strength LTCC shows an excellent mechanical reliability, against the drop impact test for example. The paper presents material design and properties of LTCC materials.

Accounting for the Strengths of MNC Subsidiaries

DEFF Research Database (Denmark)

Forsgren, Mats; Pedersen, Torben; Foss, Nicolai Juul

1999-01-01

that organizational strength can to some extent be proxied by strength in the market place. Based on analysis of data on foreign-owned production firms in Denmark, we test three hypotheses: 1) that internal factors (capabilities, patents....) are positively related to the organizational strengths of MNC subsidiaries......This paper links up with recent work on the role of subsidiaries in multinational corporations as well as with recent work in the strategy and business network literature. We discuss the sources of organizational strengths of subsidiaries in the larger multinational corporation, and argue...

Strengths and Satisfaction across the Adult Lifespan

Science.gov (United States)

Isaacowitz, Derek M.; Vaillant, George E.; Seligman, Martin E. P.

2003-01-01

Positive psychology has recently developed a classification of human strengths (Peterson & Seligman, in press). We aimed to evaluate these strengths by investigating the strengths and life satisfaction in three adult samples recruited from the community (young adult, middle-aged, and older adult), as well as in the surviving men of the Grant study…

46 CFR 45.107 - Strength of hull.

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Strength of hull. 45.107 Section 45.107 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Conditions of Assignment § 45.107 Strength of hull. The general structural strength of the hull must be sufficient for the...

Detection of rock strength at Branisko massif

Directory of Open Access Journals (Sweden)

Lazarová Edita

2000-09-01

Full Text Available When monitoring and optimizing the driving proces of the exploratory gallery by a computer system, conditions for verification of the interaction between desintegrating head of driving machine and rock massif were created. One of the output values of this mathematical model is the model strength at a simple pressure ótlH, which is defined as a pressure at the discus and the massif contact during the desintigration (a near limit of massif strength. By geological and geological engineering exploration, the section of length 2340 m was divided into fourty-two geological sections and five quasi-homogeneous massif enviroments. In the article, results of scleroscopic strength óCI , the strength in a simple pressure determined from the point load test and the strength at simple pressure ótlH are confronted . The main advance of the electronic geomechanical monitoring is the density of gained information. The two-seconds sample period of input and output data during the driving process makes it possible to describe driving circumstances in an almost continual way for each millimeter of the built tunnel. Then the information about changes of disintegrated rock properties, have the same density (frequency. By comparing a quantity of data gained by examining the index of point strength, scleroscopic strength and the model strength in a simple pressure from the monitoring process of driving process it is obvious that during the driving of exploratory gallery of motorway tunnel Branisko, a proportion of data number from the three “type examinations” of strength was reached and it was approximately 1:7:5000. Approximately in the same proportion, there were determined values for the 42 geologic sections (I. – XLII., which were defined in detail by the geologic, engineering geologic, hydrogeologic and geotechnic research.. The presented quantity values of presented rock mass strength for each geologic section are presented by their arithmetic average

Dynamic strength behavior of a Zr-based bulk metallic glass under shock loading

International Nuclear Information System (INIS)

Yu Yu-Ying; Xi Feng; Dai Cheng-Da; Cai Ling-Cang; Tan Ye; Li Xue-Mei; Wu Qiang; Tan Hua

2015-01-01

Dynamic strength behavior of Zr 51 Ti 5 Ni 10 Cu 25 Al 9 bulk metallic glass (BMG) up to 66 GPa was investigated in a series of plate impact shock-release and shock-reload experiments. Particle velocity profiles measured at the sample/LiF window interface were used to estimate the shear stress, shear modulus, and yield stress in shocked BMG. Beyond confirming the previously reported strain-softening of shear stress during the shock loading process for BMGs, it is also shown that the softened Zr-BMG still has a high shear modulus and can support large yield stress when released or reloaded from the shocked state, and both the shear modulus and the yield stress appear as strain-hardening behaviors. The work provides a much clearer picture of the strength behavior of BMGs under shock loading, which is useful to comprehensively understand the plastic deformation mechanisms of BMGs. (paper)

Reliability and relationships among handgrip strength, leg extensor strength and power, and balance in older men.

Science.gov (United States)

Jenkins, Nathaniel D M; Buckner, Samuel L; Bergstrom, Haley C; Cochrane, Kristen C; Goldsmith, Jacob A; Housh, Terry J; Johnson, Glen O; Schmidt, Richard J; Cramer, Joel T

2014-10-01

To quantify the reliability of isometric leg extension torque (LEMVC), rate of torque development (LERTD), isometric handgrip force (HGMVC) and RFD (HGRFD), isokinetic leg extension torque and power at 1.05rad·s(-1) and 3.14rad·s(-1); and explore relationships among strength, power, and balance in older men. Sixteen older men completed 3 isometric handgrips, 3 isometric leg extensions, and 3 isokinetic leg extensions at 1.05rad·s(-1) and 3.14rad·s(-1) during two visits. Intraclass correlation coefficients (ICCs), ICC confidence intervals (95% CI), coefficients of variation (CVs), and Pearson correlation coefficients were calculated. LERTD demonstrated no reliability. The CVs for LERTD and HGRFD were ≤23.26%. HGMVC wasn't related to leg extension torque or power, or balance (r=0.14-0.47; p>0.05). However, moderate to strong relationships were found among isokinetic leg extension torque at 1.05rad·s(-1) and 3.14rad·s(-1), leg extension mean power at 1.05rad·s(-1), and functional reach (r=0.51-0.95; p≤0.05). LERTD and HGRFD weren't reliable and shouldn't be used as outcome variables in older men. Handgrip strength may not be an appropriate surrogate for lower body strength, power, or balance. Instead, perhaps handgrip strength should only be used to describe upper body strength or functionality, which may compliment isokinetic assessments of lower body strength, which were reliable and related to balance. Copyright © 2014 Elsevier Inc. All rights reserved.

Freestanding bucky paper with high strength from multi-wall carbon nanotubes

International Nuclear Information System (INIS)

Li, Zhonglai; Xu, Ju; O'Byrne, Justin P.; Chen, Lan; Wang, Kaixue; Morris, Michael A.; Holmes, Justin D.

2012-01-01

Bucky papers have been investigated by some research groups, however, due to different qualities of carbon nanotubes used, various results of strength and electronic properties were reported in the literatures. In this article, the effects of carbon nanotubes synthesized over different catalysts on the qualities of bucky papers were systemically investigated. Multi-wall carbon nanotubes were synthesized over a series of MgO supported catalysts with different weight ratios of Mo and Co. As the ratios of Mo/Co in the catalysts were increased from 0 to 3, the yields of carbon nanotubes were enhanced from 7 wt% to 400 wt%. However, the yield enhancement of carbon nanotubes was achieved at the expense of higher proportion of structural defects within carbon nanotubes, which has been proved by Raman spectroscopy and thermogravimetry analysis. It was demonstrated that the tensile strength of bucky paper composed of numerous MCNTs bundles strongly depends on the structure of carbon nanotubes used. By optimizing reaction conditions, a bucky paper with high strain up to 15.36 MPa and electrical conductivity of 61.17 S cm −1 was obtained by Supercritical Fluid (SCF) drying technique. -- Highlights: ► Multi-wall carbon nanotube bucky paper. ► Structural defects of carbon nanotubes. ► CoMo catalyst. ► Tensile strength of bucky paper.

Strength of low-carbon rotor steel

International Nuclear Information System (INIS)

Voropaev, V.I.; Filimonov, O.V.; Borisov, I.A.

1988-01-01

The results of studying the effect of chemical composition and thermal treatment regimes on the structural strength of steels of the 25KhN3MFA type are presented. It is shown that alloying with niobium from 0.01 to 0.08% steels with the increased nickel content (4.2-4.5%) contributes to the increase of structural strength and reduction of semibrittleness temperature. To obtain high values of strength and plastic properties cooling with the rate of 10 3 -10 5 K/hr is recommended

Adhesion Strength of Biomass Ash Deposits

DEFF Research Database (Denmark)

Laxminarayan, Yashasvi; Jensen, Peter Arendt; Wu, Hao

2015-01-01

This study investigates the shear adhesion strength of biomass ash deposits on superheater tubes. Artificial biomass ash deposits were prepared on superheater tubes and sintered in an oven at temperatures up to 1000°C. Subsequently, the deposits were sheared off with the help of an electrically...... controlled arm. Higher sintering temperatures resulted in greater adhesion strengths, with a sharp increase observed near the melting point of the ash. Repetition of experiments with fixed operation conditions revealed considerable variation in the obtained adhesion strengths, portraying the stochastic...

Evaluation of size dependent design shear strength of reinforced ...

Indian Academy of Sciences (India)

to the development of the size dependent models on the shear strength in ... predict the diagonal cracking strength and the ultimate shear strength of RC ... ing strength of normal beams was by Zsutty (1968) based on the data base available without .... The comparison of the calculated shear strength of the beams is shown.

Performance of an Adjustable Strength Permanent Magnet Quadrupole

CERN Document Server

Gottschalk, Stephen C; Kangas, Kenneth; Spencer, Cherrill M; Volk, James T

2005-01-01

An adjustable strength permanent magnet quadrupole suitable for use in Next Linear Collider has been built and tested. The pole length is 42cm, aperture diameter 13mm, peak pole tip strength 1.03Tesla and peak integrated gradient * length (GL) is 68.7 Tesla. This paper describes measurements of strength, magnetic centerline and field quality made using an air bearing rotating coil system. The magnetic centerline stability during -20% strength adjustment proposed for beam based alignment was < 0.2 microns. Strength hysteresis was negligible. Thermal expansion of quadrupole and measurement parts caused a repeatable and easily compensated change in the vertical magnetic centerline. Calibration procedures as well as centerline measurements made over a wider tuning range of 100% to 20% in strength useful for a wide range of applications will be described. The impact of eddy currents in the steel poles on the magnetic field during strength adjustments will be reported.

Repeatability and Reproducibility of Compression Strength Measurements Conducted According to ASTM E9

Science.gov (United States)

Luecke, William E.; Ma, Li; Graham, Stephen M.; Adler, Matthew A.

2010-01-01

Ten commercial laboratories participated in an interlaboratory study to establish the repeatability and reproducibility of compression strength tests conducted according to ASTM International Standard Test Method E9. The test employed a cylindrical aluminum AA2024-T351 test specimen. Participants measured elastic modulus and 0.2 % offset yield strength, YS(0.2 % offset), using an extensometer attached to the specimen. The repeatability and reproducibility of the yield strength measurement, expressed as coefficient of variations were cv(sub r)= 0.011 and cv(sub R)= 0.020 The reproducibility of the test across the laboratories was among the best that has been reported for uniaxial tests. The reported data indicated that using diametrically opposed extensometers, instead of a single extensometer doubled the precision of the test method. Laboratories that did not lubricate the ends of the specimen measured yield stresses and elastic moduli that were smaller than those measured in laboratories that lubricated the specimen ends. A finite element analysis of the test specimen deformation for frictionless and perfect friction could not explain the discrepancy, however. The modulus measured from stress-strain data were reanalyzed using a technique that finds the optimal fit range, and applies several quality checks to the data. The error in modulus measurements from stress-strain curves generally increased as the fit range decreased to less than 40 % of the stress range.

Strength properties of interlocking compressed earth brick units

Science.gov (United States)

Saari, S.; Bakar, B. H. Abu; Surip, N. A.

2017-10-01

This study presents a laboratory investigation on the properties of interlocking compressed earth brick (ICEB) units. Compressive strength, which is one of the most important properties in masonry structures, is used to determine masonry performance. The compressive strength of the ICEB units was determined by applying a compressive strength test for 340 units from four types of ICEB. To analyze the strength of the ICEB units, each unit was capped by a steel plate at the top and bottom to create a flat surface, and then ICEB was loaded until failure. The average compressive strength of the corresponding ICEB units are as follows: wall brick, 19.15 N/mm2; beam brick, 16.99 N/mm2; column brick, 13.18 N/mm2; and half brick, 11.79 N/mm2. All the ICEB units had compressive strength of over 5 N/mm2, which is the minimum strength for a load-bearing brick. This study proves that ICEB units may be used as load-bearing bricks. The strength of ICEBs is equal to that of other common bricks and blocks that are currently available in the market.

Nutritional Supplements for Strength Power Athletes

Science.gov (United States)

Wilborn, Colin

Over the last decade research involving nutritional supplementation and sport performance has increased substantially. Strength and power athletes have specific needs to optimize their performance. Nutritional supplementation cannot be viewed as a replacement for a balanced diet but as an important addition to it. However, diet and supplementation are not mutually exclusive, nor does one depend on the other. Strength and power athletes have four general areas of supplementation needs. First, strength athletes need supplements that have a direct effect on performance. The second group of supplements includes those that promote recovery. The third group comprises the supplements that enhance immune function. The last group of supplements includes those that provide energy or have a direct effect on the workout. This chapter reviews the key supplements needed to optimize the performance and training of the strength athlete.

Ductile Bulk Aluminum-Based Alloy with Good Glass-Forming Ability and High Strength

International Nuclear Information System (INIS)

Long-Chao, Zhuo; Shu-Jie, Pang; Hui, Wang; Tao, Zhang

2009-01-01

Based on a new approach for designing glassy alloy compositions, bulk Al-based alloys with good glass-forming ability (GFA) are synthesized. The cast Al 86 Si 0.5 Ni 4.06 Co 2.94 Y 6 Sc 0.5 rod with a diameter of 1 mm shows almost fully amorphous structure besides about 5% fcc-Al nucleated in the center of the rod. The bulk alloy with high Al concentration exhibits an ultrahigh yield strength of 1.18 GPa and maximum strength of 1.27 GPa as well as an obvious plastic strain of about 2.4% during compressive deformation. This light Al-based alloy with good GFA and mechanical properties is promising as a new high specific strength material with good deformability. (condensed matter: structure, mechanical and thermal properties)

Influence of MSD crack pattern on the residual strength of flat stiffened sheets

Science.gov (United States)

Nilsson, K.-F.

A parameter study of the residual strength for a multiple site damaged (MSD) stiffened sheet is presented. The analysis is based on an elastic-plastic fracture analysis using the yield-strip model for interaction between a lead crack and the smaller MSD cracks. Two crack growth criteria, one with a pronounced crack growth resistance and one with no crack growth resistance and five different MSD crack patterns, are analysed for different sizes of the lead crack and the smaller MSD cracks. The analysis indicates that the residual strength reduction depends on all these parameters and that MSD may totally erode the crack arrest capability of a tear strap. Another important outcome is that for certain combinations also very small MSD cracks may induce a significant residual strength reduction.

Burrowing as a novel voluntary strength training method for mice : A comparison of various voluntary strength or resistance exercise methods

NARCIS (Netherlands)

Roemers, P; Mazzola, P N; De Deyn, P P; Bossers, W J; van Heuvelen, M J G; van der Zee, E A

2018-01-01

BACKGROUND: Voluntary strength training methods for rodents are necessary to investigate the effects of strength training on cognition and the brain. However, few voluntary methods are available. NEW METHOD: The current study tested functional and muscular effects of two novel voluntary strength

Geometry and gravity influences on strength capability

Science.gov (United States)

Poliner, Jeffrey; Wilmington, Robert P.; Klute, Glenn K.

1994-01-01

Strength, defined as the capability of an individual to produce an external force, is one of the most important determining characteristics of human performance. Knowledge of strength capabilities of a group of individuals can be applied to designing equipment and workplaces, planning procedures and tasks, and training individuals. In the manned space program, with the high risk and cost associated with spaceflight, information pertaining to human performance is important to ensuring mission success and safety. Knowledge of individual's strength capabilities in weightlessness is of interest within many areas of NASA, including workplace design, tool development, and mission planning. The weightless environment of space places the human body in a completely different context. Astronauts perform a variety of manual tasks while in orbit. Their ability to perform these tasks is partly determined by their strength capability as demanded by that particular task. Thus, an important step in task planning, development, and evaluation is to determine the ability of the humans performing it. This can be accomplished by utilizing quantitative techniques to develop a database of human strength capabilities in weightlessness. Furthermore, if strength characteristics are known, equipment and tools can be built to optimize the operators' performance. This study examined strength in performing a simple task, specifically, using a tool to apply a torque to a fixture.

Pinch Strengths in Healthy Iranian Children and Young Adult Population

Directory of Open Access Journals (Sweden)

Iman Dianat

2015-03-01

Full Text Available Background: Data on the physical strength capabilities are essential for design-ing safe and usable products and are useful in a wide range of clinical settings especially during treatment of disease affecting the function of the hand. The purpose of this study was to determine peak lateral pinch strength, key pinch strength, tip-to-tip pinch strength and three-jaw pinch strength exertions in a healthy Iranian children and young adult population.Methods: The study was conducted among 511 participants (242 males and 269 females aged 7-30 years. Measurements were carried out with both dominant and non-dominant hands in standard sitting posture using a B&L pinch gauge. Two repetitions of each strength measurement were recorded for each condition and the average value of the two trials was used in the subsequent analysis.Results: The results showed significant differences in the pinch strength data in terms of the age, gender and hand dominance. The lateral pinch strength, key pinch strength, tip-to-tip pinch strength and three-jaw pinch strength exertions by females were 68.4%, 68.8%, 78.8% and 81.8% of those exerted by males, respectively. Strength exertions with the non-dominant hand were 6.4%, 5.2%, 6.6% and 5.1% lower than strength exertions of the dominant hand for the lat-eral pinch strength, key pinch strength, tip-to-tip pinch strength and three-jaw pinch strength exertions, respectively.Conclusion: These findings can be used to fill the gaps in strength data for Iranian population.

Slippage of steel in high and normal strength concrete

International Nuclear Information System (INIS)

Ahmed, K.; Siddiqi, Z.A.; Yousaf, M.

2007-01-01

Composite action of any reinforced concrete member is only possible if sufficient bond strength exists between steel reinforcing bars and concrete, which can adequately transfer shear stress between them. Bond strength is a function of compressive strength of concrete and hence high strength concrete has higher bond strength (1-2). Therefore required development length can be reduced. In order to investigate the effect of development length on bond stress and slip relationships, experimental investigation was carried out. In this experimentation 24 pull-out samples of high strength concrete and normal strength concrete were casted and tested. The results of this investigation revealed that by increasing the development length from 5db to 10db bond strength increases for both high and normal strength concrete as shown in Figure 11, 12 and 13. However in case of normal strength concrete increase in bond strength is more compared to that in high strength concrete as it is clear from Figure 11 and Figure 13. The increase in bond strength is observed even at 10db development length but the extent is less for 19 mm than 16 mm bars as shown in Figure 12 and Figure 13. This is in agreement with the earlier findings of Chen et al (3) and Harajli et al (1). However in case of HSC the total slippage at 10db is 50% greater than at 5db. This may be due to the fact that more no of concrete keys participate in resisting the slippage. (author)

Effect of laser welding on the titanium ceramic tensile bond strength

Directory of Open Access Journals (Sweden)

Rodrigo Galo

2011-08-01

Full Text Available Titanium reacts strongly with elements, mainly oxygen at high temperature. The high temperature of titanium laser welding modifies the surface, and may interfere on the metal-ceramic tensile bond strength. OBJECTIVE: The influence of laser welding on the titanium-ceramic bonding has not yet been established. The purpose of this in vitro study was to analyze the influence of laser welding applied to commercially pure titanium (CpTi substructure on the bond strength of commercial ceramic. The influence of airborne particle abrasion (Al2O3 conditions was also studied. MATERIAL AND METHODS: Forty CpTi cylindrical rods (3 mm x 60 mm were cast and divided into 2 groups: with laser welding (L and without laser welding (WL. Each group was divided in 4 subgroups, according to the size of the particles used in airborne particle abrasion: A - Al2O3 (250 µm; B - Al2O3 (180 µm; C - Al2O3 (110 µm; D - Al2O3 (50 µm. Ceramic rings were fused around the CpTi rods. Specimens were invested and their tensile strength was measured at fracture with a universal testing machine at a crosshead speed of 2.0 mm/min and 200 kgf load cell. Statistical analysis was carried out with analysis of variance and compared using the independent t test (p<0.05. RESULTS: Significant differences were found among all subgroups (p<0.05. The highest and the lowest bond strength means were recorded in subgroups WLC (52.62 MPa and LD (24.02 MPa, respectively. CONCLUSION: Airborne particle abrasion yielded significantly lower bond strength as the Al2O3 particle size decreased. Mechanical retention decreased in the laser-welded specimens, i.e. the metal-ceramic tensile bond strength was lower.

Strength testing and training of rowers: a review.

Science.gov (United States)

Lawton, Trent W; Cronin, John B; McGuigan, Michael R

2011-05-01

In the quest to maximize average propulsive stroke impulses over 2000-m racing, testing and training of various strength parameters have been incorporated into the physical conditioning plans of rowers. Thus, the purpose of this review was 2-fold: to identify strength tests that were reliable and valid correlates (predictors) of rowing performance; and, to establish the benefits gained when strength training was integrated into the physical preparation plans of rowers. The reliability of maximal strength and power tests involving leg extension (e.g. leg pressing) and arm pulling (e.g. prone bench pull) was high (intra-class correlations 0.82-0.99), revealing that elite rowers were significantly stronger than their less competitive peers. The greater strength of elite rowers was in part attributed to the correlation between strength and greater lean body mass (r = 0.57-0.63). Dynamic lower body strength tests that determined the maximal external load for a one-repetition maximum (1RM) leg press (kg), isokinetic leg extension peak force (N) or leg press peak power (W) proved to be moderately to strongly associated with 2000-m ergometer times (r = -0.54 to -0.68; p training experience and muscle morphology, in that those individuals with greater training experience and/or proportions of slow twitch fibres performed more repetitions. Muscle balance ratios derived from strength data (e.g. hamstring-quadriceps ratio training may be counterproductive to strength development over the shorter term (i.e. training within the sequence of training units should be considered, particularly over the non-competition phase (e.g. 2-6 sets × 4-12 repetitions, three sessions a week). Maximal strength was sustained when infrequent (e.g. one or two sessions a week) but intense (e.g. 73-79% of maximum) strength training units were scheduled; however, it was unclear whether training adaptations should emphasize maximal strength, endurance or power in order to enhance

Interactive effects of music tempi and intensities on grip strength and subjective affect.

Science.gov (United States)

Karageorghis, C I; Cheek, P; Simpson, S D; Bigliassi, M

2018-03-01

Pretask music is widely used by athletes albeit there is scant empirical evidence to support its use. The present study extended a line of work into pretask music by examining the interactive effects of music tempo and intensity (volume) on the performance of a simple motor skill and subjective affect. A 2 × 2 within-subjects factorial design was employed with an additional no-music control, the scores from which were used as a covariate. A sample of 52 male athletes (M age  = 26.1 ± 4.8 years) was exposed to five conditions: fast/loud (126 bpm/80 dBA), fast/quiet (126 bpm/70 dBA), slow/loud (87 bpm/80 dBA), slow/quiet (87 bpm/70 dBA) music, and a no-music control. Dependent variables were grip strength, measured with a handgrip dynamometer, and subjective affect, assessed by use of the Affect Grid. The tempo and intensity components of music had interactive effects for grip strength but only main effects for subjective affect. Fast-tempo music played at a high intensity yielded the highest grip strength, while fast-tempo music played at a low-intensity resulted in much lower grip strength (M diff.  = -1.11 Force kg). For affective valence, there were main effects of tempo and intensity, with fast and loud music yielding the highest scores. For affective arousal, there was no difference between tempi although there was between intensities, with the high-intensity condition yielding higher scores. The present findings indicate the utility of fast/loud pretask music in enhancing affective valence and arousal in preparation for a simple or gross motor task. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of different strength training frequencies on maximum strength, body composition and functional capacity in healthy older individuals.

Science.gov (United States)

Turpela, Mari; Häkkinen, Keijo; Haff, Guy Gregory; Walker, Simon

2017-11-01

There is controversy in the literature regarding the dose-response relationship of strength training in healthy older participants. The present study determined training frequency effects on maximum strength, muscle mass and functional capacity over 6months following an initial 3-month preparatory strength training period. One-hundred and six 64-75year old volunteers were randomly assigned to one of four groups; performing strength training one (EX1), two (EX2), or three (EX3) times per week and a non-training control (CON) group. Whole-body strength training was performed using 2-5 sets and 4-12 repetitions per exercise and 7-9 exercises per session. Before and after the intervention, maximum dynamic leg press (1-RM) and isometric knee extensor and plantarflexor strength, body composition and quadriceps cross-sectional area, as well as functional capacity (maximum 7.5m forward and backward walking speed, timed-up-and-go test, loaded 10-stair climb test) were measured. All experimental groups increased leg press 1-RM more than CON (EX1: 3±8%, EX2: 6±6%, EX3: 10±8%, CON: -3±6%, Ptraining frequency would induce greater benefit to maximum walking speed (i.e. functional capacity) despite a clear dose-response in dynamic 1-RM strength, at least when predominantly using machine weight-training. It appears that beneficial functional capacity improvements can be achieved through low frequency training (i.e. 1-2 times per week) in previously untrained healthy older participants. Copyright © 2017 Elsevier Inc. All rights reserved.

Equipment and Protocols for Quasi-Static and Dynamic Tests of Very-High-Strength Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC)

Science.gov (United States)

2016-08-01

Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC) En gi ne er R es ea rc h an d D ev el op m en t Ce nt er Brett A...Very-High-Strength Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC) Brett A. Williams, Robert D. Moser, William F. Heard, Carol F...equipment and protocols for tests of both very-high-strength concrete (VHSC) and high- strength high-ductility concrete (HSHDC) to predict blast

Upper extremity injuries associated with strength training.

Science.gov (United States)

Haupt, H A

2001-07-01

Most injuries sustained during strength training are mild strains that resolve with appropriate rest. More severe injuries include traumatic shoulder dislocations, tendon ruptures of the pectoralis major, biceps, and triceps; stress fractures of the distal clavicle, humerus, radius, and ulna; traumatic fractures of the distal radius and ulna in adolescent weightlifters; and compressive and stretch neuropathies. These more severe injuries are usually the result of improperly performing a strength training exercise. Educating athletes regarding proper strength-training techniques serves to reverse established injury patterns and to prevent these injuries in the first place. Recognizing the association of anabolic steroid use to several of the injury patterns further reinforces the need for medical specialists to counsel athletes against their use. With the increasing use of supplements such as creatine, the incidence and nature of strength-training injuries may change further. Greater emphasis on the competitive performance of younger athletes undoubtedly will generate enthusiasm for strength training at earlier ages in both sexes. The importance of proper supervision of these young athletes by knowledgeable persons will increase. As the popularity of strength training grows, there will be ample opportunity to continue to catalog the injury patterns associated with this activity.

Nuclear threshold effects and neutron strength function

International Nuclear Information System (INIS)

Hategan, Cornel; Comisel, Horia

2003-01-01

One proves that a Nuclear Threshold Effect is dependent, via Neutron Strength Function, on Spectroscopy of Ancestral Neutron Threshold State. The magnitude of the Nuclear Threshold Effect is proportional to the Neutron Strength Function. Evidence for relation of Nuclear Threshold Effects to Neutron Strength Functions is obtained from Isotopic Threshold Effect and Deuteron Stripping Threshold Anomaly. The empirical and computational analysis of the Isotopic Threshold Effect and of the Deuteron Stripping Threshold Anomaly demonstrate their close relationship to Neutron Strength Functions. It was established that the Nuclear Threshold Effects depend, in addition to genuine Nuclear Reaction Mechanisms, on Spectroscopy of (Ancestral) Neutron Threshold State. The magnitude of the effect is proportional to the Neutron Strength Function, in their dependence on mass number. This result constitutes also a proof that the origins of these threshold effects are Neutron Single Particle States at zero energy. (author)

Normative data for hand grip strength and key pinch strength, stratified by age and gender for a multiethnic Asian population.

Science.gov (United States)

Lam, Ngee Wei; Goh, Hui Ting; Kamaruzzaman, Shahrul Bahyah; Chin, Ai-Vyrn; Poi, Philip Jun Hua; Tan, Maw Pin

2016-10-01

Hand strength is a good indicator of physical fitness and frailty among the elderly. However, there are no published hand strength references for Malaysians aged > 65 years. This study aimed to establish normative data for hand grip strength (HGS) and key pinch strength (KPS) for Malaysians aged ≥ 60 years, and explore the relationship between hand strength and physical ability. Healthy participants aged ≥ 60 years with no neurological conditions were recruited from rural and urban locations in Malaysia. HGS and KPS were measured using hand grip and key pinch dynamometers. Basic demographic data, anthropometric measures, modified Barthel Index scores and results of the Functional Reach Test (FRT), Timed Up and Go (TUG) test and Jebsen-Taylor Hand Function Test (JTHFT) were recorded. 362 subjects aged 60-93 years were recruited. The men were significantly stronger than the women in both HGS and KPS (p Malaysia. Future studies are required to determine the modifiable factors for poor hand strength. Copyright: © Singapore Medical Association

Hip adduction and abduction strength profiles in elite soccer players

DEFF Research Database (Denmark)

Thorborg, Kristian; Serner, Andreas; Petersen, Jesper

2011-01-01

An ipsilateral hip adduction/abduction strength ratio of more than 90%, and hip adduction strength equal to that of the contralateral side have been suggested to clinically represent adequate strength recovery of hip adduction strength in athletes after groin injury. However, to what extent side-......-to-side symmetry in isometric hip adduction and abduction strength can be assumed in soccer players remains uncertain.......An ipsilateral hip adduction/abduction strength ratio of more than 90%, and hip adduction strength equal to that of the contralateral side have been suggested to clinically represent adequate strength recovery of hip adduction strength in athletes after groin injury. However, to what extent side...

Promoting positive outcomes through strengths interventions : A literature review

NARCIS (Netherlands)

Ghielen, S.T.S.; van Woerkom, M.; Meyers, M.C.

2018-01-01

This paper reviews studies of strengths interventions published between 2011 and 2016. Strengths interventions aim to promote well-being or other positive outcomes by facilitating strengths identification, and sometimes also strengths use and/or development. The present review provides an overview

THE EFFECT OF DEGREASING ON ADHESIVE JOINT STRENGTH

Directory of Open Access Journals (Sweden)

Anna Rudawska

2017-03-01

Full Text Available The paper investigates the effect of degreasing, a surface preparation methods in adhesive bonding, on adhesive joint strength. 5 types of degreasing agents were used in the study: acetone, extraction naphtha, Ultramyt, Wiko and Loctite 7061. The degreasing operation was performed by three methods: rubbing, spraying and immersion. Strength tests were performed on single-lap adhesive joints of hot-dip galvanized metal sheets made with Loctite 9466 adhesive according to the above variants of surface preparation. The experimental results demonstrate that adhesive joint strength is significantly affected by the applied degreasing agent. Moreover, the method of application of the degreasing agent is crucial, too. The results of strength testing reveal that the most effective degreasing method for hot-dip galvanized metal sheet adhesive joints is spraying using extraction naphtha. Thereby degreased samples have the highest immediate strength and shear strength. The use of extraction naph-tha is also effective in combination with degreasing by rubbing; however, it is not effective when used in combi-nation with immersion, as reflected in the lowest strength results.

Tensile strength of glulam laminations of Nordic spruce

DEFF Research Database (Denmark)

Hoffmeyer, Preben; Bräuner, Lise; Boström, Lars

1999-01-01

Design of glulam according to the European timber code Eurocode 5 is based on the standard document prEN1194 , according to which glulam beam strength is to be established either by full scale testing or by calculation. The calculation must be based on a knowledge of lamination tensile strength....... This knowledge may be obtained either by adopting a general rule that the characteristic tensile strength is sixty percent of the characteristic bending strength, or by performing tensile tests on an adequate number of laminations representative of the whole population. The present paper presents...... an investigation aimed at establishing such an adequate experimental background for the assignment of strength classes for glulam made of visually strength graded laminations from Nordic sawmills. The investigation includes more than 1800 boards (laminations) of Norway spruce (Picea abies) sampled from eight...

Efficacy of strength training on tension-type headache

DEFF Research Database (Denmark)

Madsen, Bjarne K; Søgaard, Karen; Andersen, Lars L

2018-01-01

Background Strength training has shown effects in reducing neck pain. As neck pain is highly prevalent in tension-type headache (TTH), it is relevant to examine the effect of strength training of the shoulder muscles on TTH patients. Aim To examine the effect of strength training of the shoulder....../neck muscles on TTH frequency and duration. Methods Sixty patients with TTH were randomised into strength training or a control group. The strength training group trained ten weeks with elastic resistance bands. The control group performed ergonomic and posture correction. Efficacy was evaluated at follow......-up after 19-22 weeks. Results Twenty-three patients completed strength training and 21 completed ergonomic and posture correction (per-protocol). No between-group effect was detected, but within groups numerical reductions were noted in both groups from baseline to follow-up. Frequency of TTH...

University Student's Physical Strength and Amount of Exercise

OpenAIRE

高橋, ひとみ; Hitomi, TAKAHASHI; 桃山学院大学文学部

1997-01-01

To determine the importance of developing physical strength in health maintenance by unversity students, I conducted a simple examination of the physical strength and the living conditions of Momoyama Gakuin University students. I examined the relationship between the student's physical condition and the results of their strength test, between the importance of exercise and the student's evaluation of their own physical strength, and between the need for exercise and the test results. The res...

Body Build and the Level of Development of Muscle Strength Among Male Jiu-Jitsu Competitors and Strength-Trained Adults

Directory of Open Access Journals (Sweden)

Pietraszewska Jadwiga

2014-09-01

Full Text Available Purpose. The aim of the present study was to assess the morpho-functional characteristics of male jiu-jitsu practitioners against a sample of strength-trained university students. Methods. The all-male research sample included 49 jiu-jitsu competitors and 30 university students actively involved in strength training. Measures of body mass and height, lower extremity length, sitting height, arm span, trunk width, skeletal breadths, circumferences and skinfold thicknesses of the trunk and extremities were collected. Body tissue composition was assessed using bioelectrical impedance analysis. Somatotype was classified according to the anthropometric method of Heath and Carter. Participants also performed three motor tests composed of the standing long jump, flexed arm hang, and sit-ups and two dynamometer tests measuring handgrip and back muscle strength. Differences between the measured characteristics in both samples were analyzed using Student’s t test. Pearson’s correlation coefficient was used to the determine the relationships between the morphological characteristics and the results of the motor tests. Results. The jiu-jitsu sample was slightly smaller than the strength-training students. In contrast, body mass was almost identical in both groups. The remaining length, height, and skinfold characteristics also did not differ significantly between the groups. Only hip breadth was significantly larger in the jiu-jitsu sample. No between-group differences were noted in the levels of endomorphy, mesomorphy, and ectomorphy. The composite somatotype of the jiu-jitsu athletes (2.1-5.8-2.0 was very similar to that of the strength-trained students (2.1-5.9-2.4. Statistically significant differences were observed in the tests assessing muscle strength. Handgrip and back muscle strength was greater in the strength-training students, whereas the jiu-jitsu athletes performed better in all three motor tests. Conclusions. The minor morphological

Strength evaluation code STEP for brittle materials

International Nuclear Information System (INIS)

Ishihara, Masahiro; Futakawa, Masatoshi.

1997-12-01

In a structural design using brittle materials such as graphite and/or ceramics it is necessary to evaluate the strength of component under complex stress condition. The strength of ceramic materials is said to be influenced by the stress distribution. However, in the structural design criteria simplified stress limits had been adopted without taking account of the strength change with the stress distribution. It is, therefore, important to evaluate the strength of component on the basis of the fracture model for brittle material. Consequently, the strength evaluation program, STEP, on a brittle fracture of ceramic materials based on the competing risk theory had been developed. Two different brittle fracture modes, a surface layer fracture mode dominated by surface flaws and an internal fracture mode by internal flaws, are treated in the STEP code in order to evaluate the strength of brittle fracture. The STEP code uses stress calculation results including complex shape of structures analyzed by the generalized FEM stress analysis code, ABAQUS, so as to be possible to evaluate the strength of brittle fracture for the structures having complicate shapes. This code is, therefore, useful to evaluate the structural integrity of arbitrary shapes of components such as core graphite components in the HTTR, heat exchanger components made of ceramics materials etc. This paper describes the basic equations applying to the STEP code, code system with a combination of the STEP and the ABAQUS codes and the result of the verification analysis. (author)

Measuring Relative Coupling Strength in Circadian Systems.

Science.gov (United States)

Schmal, Christoph; Herzog, Erik D; Herzel, Hanspeter

2018-02-01

Modern imaging techniques allow the monitoring of circadian rhythms of single cells. Coupling between these single cellular circadian oscillators can generate coherent periodic signals on the tissue level that subsequently orchestrate physiological outputs. The strength of coupling in such systems of oscillators is often unclear. In particular, effects on coupling strength by varying cell densities, by knockouts, and by inhibitor applications are debated. In this study, we suggest to quantify the relative coupling strength via analyzing period, phase, and amplitude distributions in ensembles of individual circadian oscillators. Simulations of different oscillator networks show that period and phase distributions become narrower with increasing coupling strength. Moreover, amplitudes can increase due to resonance effects. Variances of periods and phases decay monotonically with coupling strength, and can serve therefore as measures of relative coupling strength. Our theoretical predictions are confirmed by studying recently published experimental data from PERIOD2 expression in slices of the suprachiasmatic nucleus during and after the application of tetrodotoxin (TTX). On analyzing the corresponding period, phase, and amplitude distributions, we can show that treatment with TTX can be associated with a reduced coupling strength in the system of coupled oscillators. Analysis of an oscillator network derived directly from the data confirms our conclusions. We suggest that our approach is also applicable to quantify coupling in fibroblast cultures and hepatocyte networks, and for social synchronization of circadian rhythmicity in rodents, flies, and bees.

Effect of insulating concrete forms in concrete compresive strength

Science.gov (United States)

Martinez Jerez, Silvio R.

The subject presented in this thesis is the effect of Insulating Concrete Forms (ICF's) on concrete compressive strength. This work seeks to identify if concrete cured in ICF's has an effect in compressive strength due to the thermal insulation provided by the forms. Modern construction is moving to energy efficient buildings and ICF's is becoming more popular in new developments. The thesis used a concrete mixture and a mortar mixture to investigate the effects of ICF's on concrete compressive strength. After the experimentations were performed, it was concluded that the ICF's do affect concrete strength. It was found that the forms increase concrete strength without the need for additional curing water. An increase of 50% in strength at 56 days was obtained. It was concluded that the longer concrete cures inside ICF's, the higher strength it reaches, and that ICF's effect on concrete strength is proportional to volume of concrete.

Adhesion Strength of Biomass Ash Deposits

DEFF Research Database (Denmark)

Laxminarayan, Yashasvi; Jensen, Peter Arendt; Wu, Hao

2016-01-01

. Therefore, timely removal of ash deposits is essential for optimal boiler operation. In order to improve the qualitative and quantitative understanding of deposit shedding in boilers, this study investigates the shear adhesion strength of biomass ash deposits on superheater tubes. Artificial biomass ash...... deposits were prepared on superheater tubes and sintered in an oven at temperatures up to 1000 °C. Subsequently, the deposits were sheared off by an electrically controlled arm, and the corresponding adhesion strength was measured. The results reveal the effect of temperature, ash/deposit composition......, sintering duration, and steel type on the adhesion strength....

Short Communications Strength Properties and Groups of Major ...

African Journals Online (AJOL)

Short Communications Strength Properties and Groups of Major Commercial Timbers Grown in Kenya. ... The strength groups developed revealed that most species in Kenya are suitable for heavy engineering works and building construction. ... strength properties, commercial timber, physical and mechanical properties

(p,γ) resonance strengths in the s-d shell

International Nuclear Information System (INIS)

Paine, B.M.; Sargood, D.G.

1979-01-01

The strengths of selected resonances in the energy range 0.5-2.0 MeV in the (p,γ) reactions on 26 Mg, 30 Si, 34 S, 37 C1, 39 K and 40 Ca have been found relative to the 632 and 992 keV resonances in 27 A1(p,γ) 28 Si by relative yield measurements. Absolute measurements were conducted on the selected resonances in 27 A1(p,γ) 28 Si and 30 Si(p,γ) 31 p by semi-thick target and thin target techniques with the target thickness, needed for the latter technique, found by Rutherford backscattering of protons. Absolute strengths for all of the resonances treated, together with one from each of 23 Na, 31 p and 35 C1, reported in a previous paper, were deduced by normalizing to the absolute measurements on the 27 A1(p,γ) 28 Si resonances

Brief Report: Loss of Muscle Strength Prior to Knee Replacement: A Question of Anatomic Cross-Sectional Area or Specific Strength?

Science.gov (United States)

Culvenor, Adam G; Hamler, Felix C; Kemnitz, Jana; Wirth, Wolfgang; Eckstein, Felix

2018-02-01

To determine whether loss in thigh muscle strength prior to knee replacement is caused by reductions of muscle strength in the anatomic cross-sectional area or by reductions of specific strength. All 100 of the participants in the Osteoarthritis Initiative who underwent knee replacement and whose medical records included data on thigh isometric muscle strength and magnetic resonance imaging (MRI) (58 women, and 42 men, mean ± SD age 65 ± 8 years, mean ± SD body mass index [BMI] 29 ± 5 kg/m 2 ) were matched with a control (no knee replacement) for age, sex, height, BMI, and radiographic severity. Thigh muscle anatomic cross-sectional area was determined by MRI at the research visit before knee replacement (time 0) and 2 years before time 0 (time -2). Specific strength (strength/anatomic cross-sectional area) was calculated, and the measures were compared by conditional logistic regression (i.e., odds ratio [OR] per standard deviation). ORs adjusted for pain (OR adj ) and 95% confidence intervals (95% CIs) were also calculated. Knee replacement cases had significantly smaller extensor (but not flexor) anatomic cross-sectional areas than controls at time 0 (women, OR adj 1.89 [95% CI 1.05-3.90]; men, OR adj 2.22 [95% CI 1.04-4.76]), whereas no significant differences were found at time -2. Women who had knee replacement showed lower levels of extensor specific strength than controls at time 0 (OR 1.59 [95% CI 1.02-2.50]), although this difference was not observed in men and did not maintain significance after adjustment for pain (OR adj 1.22 [95% CI 0.71-2.08]). Female cases lost significantly more extensor specific strength between time -2 and time 0 than controls (OR adj 3.76 [95% CI 1.04-13.60]), whereas no significant differences were noted at time -2, or in men. Prior to knee replacement, a significant reduction in knee extensor strength appears to occur in women through 2 mechanisms: one driven by pain (loss of specific strength) and one independent of pain

Calcium Lactate addition in Bioconcrete: Effect on Compressive strength and Water penetration

Directory of Open Access Journals (Sweden)

Irwan J.M

2016-01-01

Full Text Available This paper presents compressive strength and water penetration of bioconcrete with addition of calcium lactate. Bioconcrete has higher engineering concrete properties and durability compared to normal concrete but the natural production of calcium carbonate is limited to the calcium content in cement. Therefore, additional calcium is added as an additional calcium source to study the influence towards compressive strength and water penetration. The bacteria used in this research are Enterococcus faecalis and Bacillus sp. Calcium lactate was added into concrete mix in concentrations of 0.001mol/l, 0.005mol/l and 0.01mol/l of liquid used. The concentration of bacteria added into the mix is by partial replacement of water used in casting, which are 3% for Enterococcus faecalis and 5% for Bacillus sp. Both compressive strength and water penetration test used cubes of 150mm × 150mm × 150mm. The cubes were tested after 28 days. The result of compressive strength for control is 36 MPa while partial replacement of bacteria yields 38.2 MPa for 3% Enterococcus faecalis and 37.0 MPa for 5% Bacillus sp. Calcium lactate with 0.005 mol/L has the best performance with 42.8 MPa for Enterococcus faecalis and 39.6 MPa for Bacillus sp. Whereas for water penetration, the best concentration of calcium lactate which yielded the lowest water penetration is 0.01 mol/l for both Enterococcus faecalis and Bacillus sp which are 8.7 cm and 8 cm respectively. The addition of calcium lactate into bioconcrete is quite promising for improvement of concrete properties and durability.

Humidity effects on wire insulation breakdown strength.

Energy Technology Data Exchange (ETDEWEB)

Appelhans, Leah

2013-08-01

Methods for the testing of the dielectric breakdown strength of insulation on metal wires under variable humidity conditions were developed. Two methods, an ASTM method and the twisted pair method, were compared to determine if the twisted pair method could be used for determination of breakdown strength under variable humidity conditions. It was concluded that, although there were small differences in outcomes between the two testing methods, the non-standard method (twisted pair) would be appropriate to use for further testing of the effects of humidity on breakdown performance. The dielectric breakdown strength of 34G copper wire insulated with double layer Poly-Thermaleze/Polyamide-imide insulation was measured using the twisted pair method under a variety of relative humidity (RH) conditions and exposure times. Humidity at 50% RH and below was not found to affect the dielectric breakdown strength. At 80% RH the dielectric breakdown strength was significantly diminished. No effect for exposure time up to 140 hours was observed at 50 or 80%RH.

Strength and power of knee extensor muscles

Directory of Open Access Journals (Sweden)

Knežević Olivera

2011-01-01

Full Text Available In the studies of human neuromuscular function, the function of leg muscles has been most often measured, particularly the function of the knee extensors. Therefore, this review will be focused on knee extensors, methods for assessment of its function, the interdependence of strength and power, relations that describe these two abilities and the influence of various factors on their production (resistance training, stretching, movement tasks, age, etc.. Given that it consists of four separate muscles, the variability of their anatomical characteristics affects their participation in strength and power production, depending on the type of movement and motion that is performed. Since KE is active in a variety of activities it must be able to generate great strength in a large and diverse range of muscle lengths and high shortening velocities, in respect to different patterns of strength production, and thus different generation capacities within the muscle (Blazevich et al., 2006. It has been speculated that KE exerts its Pmax at workloads close to subject's own body weight or lower (Rahmani et al., 2001, which is very close to the maximum dynamic output hypothesis (MDI of Jaric and Markovic (2009. Changes under the influence of resistance training or biological age are variously manifested in muscle's morphological, physiological and neural characteristics, and thus in strength and power. Understanding the issues related to strength and power as abilities of great importance for daily activities, is also important for sports and rehabilitation. Performances improvement in sports in which leg muscles strength and power are crucial, as well as recovery after the injuries, are largely dependent on the research results regarding KE function. Also, the appropriate strength balance between knee flexors and extensors is important for the knee joint stability, so that the presence of imbalance between these two muscle groups might be a risk factor for

Restorative Justice as Strength-Based Accountability

Science.gov (United States)

Ball, Robert

2003-01-01

This article compares strength-based and restorative justice philosophies for young people and their families. Restorative justice provides ways to respond to crime and harm that establish accountability while seeking to reconcile members of a community. Restorative approaches are an important subset of strength-based interventions.

Thermoelastic/plastic analysis of waste-container sleeve: III. Influence of salt strength on sleeve loading. Technical memorandum report (RSI-0018)

International Nuclear Information System (INIS)

Pariseau, W.G.

1975-01-01

Three combinations of salt tensile, compressive and shear strength in linear and nonlinear yield conditions used in the axially symmetric, large displacement thermoelastic/plastic waste-container/sleeve loading estimates show no influence on the analysis. The salt remains elastic throughout the excavation and subsequent 10 year heating period. Tensile stresses are not observed, tensile strength is thus not important to the analysis even at 10 percent of the compressive strength value. Although strictly applicable only to the conditions of the analyses reported here, the capability for incorporating arbitrary strength combinations in linear or non-linear yield conditions is demonstrated. Computer plots of principal stresses and displacement fields at various stages of the excavation and heating simulation aid in the visualization of repository concept mechanics and show the possible need for additional mesh refinement for more precise stress information

The Effects of Design Strength, Fly Ash Content and Curing Method on Compressive Strength of High Volume Fly Ash Concrete: A Design of Experimental

Directory of Open Access Journals (Sweden)

Solikin Mochamad

2017-01-01

Full Text Available High volume fly ash concrete becomes one of alternatives to produce green concrete as it uses waste material and significantly reduces the utilization of Portland cement in concrete production. Although using less cement, its compressive strength is comparable to ordinary Portland cement (hereafter OPC and the its durability increases significantly. This paper reports investigation on the effect of design strength, fly ash content and curing method on compressive strength of High Volume Fly Ash Concrete. The experiment and data analysis were prepared using minitab, a statistic software for design of experimental. The specimens were concrete cylinder with diameter of 15 cm and height of 30 cm, tested for its compressive strength at 56 days. The result of the research demonstrates that high volume fly ash concrete can produce comparable compressive strength which meets the strength of OPC design strength especially for high strength concrete. In addition, the best mix proportion to achieve the design strength is the combination of high strength concrete and 50% content of fly ash. Moreover, the use of spraying method for curing method of concrete on site is still recommended as it would not significantly reduce the compressive strength result.

Influence of multiaxial preloading on the strength of concrete

International Nuclear Information System (INIS)

Linse, D.

1975-01-01

In a preliminary study about the influence of the loading direction discs of 20/20/5 cm were loaded at different stress-rates in one direction, then unloaded and loaded up to failure again. Two series of each about 15 specimens were tested: the first series was reloaded in the same direction as it was loaded before. If the preloading was not greater than about 90% of the original short-term uniaxial strength βsub(p), one could achieve in the second loading a higher strength than the strength βsub(p). The second series was reloaded normal to the direction of preloading. By an other series of about 50 specimens the influence of triaxial preloading on the uniaxial strength of concrete was tested. Cubes of 10cm were loaded by brush bearing platens up to a stress which was maximally three times higher than the uniaxial short-term strength βsub(p), then unloaded and tested again under uniaxial compression. The achieved ultimate strength of the cubes at the second loading was obviously dependent upon the stress-state and the stress-rate of the preloading. Multiaxial preloading which is far below the ultimate multiaxial strength can considerably defect the remaining strength of concrete. The decrease in strength was defined by the reduction of the uniaxial strength. It can be assumed that the remaining multiaxial strength is reduced at least to the same rate. Further tests are planned

Tools for Building on Youth Strengths

Science.gov (United States)

Cox, Kathy

2008-01-01

While rhetoric about strength-based approaches abounds, this perspective has not penetrated the front lines of practice. Many programs serving troubled youngsters are still mired in a deficit and deviance orientation. This article provides practical strategies for assessing the strengths of children and developing interventions to tap their assets…

Strength optimized designs of thermoelastic structures

DEFF Research Database (Denmark)

Pedersen, Pauli; Pedersen, Niels Leergaard

2010-01-01

For thermoelastic structures the same optimal design does not simultaneously lead to minimum compliance and maximum strength. Compliance may be a questionable objective and focus for the present paper is on the important aspect of strength, quantified as minimization of the maximum von Mises stre...... loads are appended....

Effects of drought stress on seed sink strength and leaf protein ...

African Journals Online (AJOL)

Assimilate availability and the capacity to utilise them in the reproductive structures to a large extent determine reproductive sink establishment and yield of crops under drought stress. This study was carried out to investigate the effect of drought stress imposed at early pod-fill stage on seed sink strength of common bean ...

Strength Training Following Hematopoietic Stem Cell Transplantation

Science.gov (United States)

Hacker, Eileen Danaher; Larson, Janet; Kujath, Amber; Peace, David; Rondelli, Damiano; Gaston, Lisa

2010-01-01

Background Patients receiving high-dose chemotherapy and hematopoietic stem cell transplantation (HSCT) experience considerable reductions in physical activity and deterioration of their health status. Objective The purpose of this pilot study was to test the effects of strength training compared to usual activity on physical activity, muscle strength, fatigue, health status perceptions, and quality of life following HSCT. Interventions/Methods Nineteen subjects were randomized to the exercise or control group. Moderate intensity strength training began following discharge from the hospital. Dependent variables included physical activity, muscle strength, fatigue, health status perceptions and quality of life. Variables were measured prior to admission to the hospital for HSCT, day 8 following HSCT, and six weeks following discharge from the hospital. Results Significant time effects were noted for many variables with anticipated declines in physical activity, muscle strength, fatigue, and health status perceptions immediately after HSCT with subsequent improvements six weeks following hospital discharge. One group effect was noted with subjects in the exercise group reporting less fatigue than subjects in the control group. Although no significant interactions were detected, the trends suggest that the exercise group may be more physically active following the intervention compared to the usual activity group. Conclusions This study demonstrates the potential positive effects of strength training on physical activity, fatigue, and quality of life in people receiving high-dose chemotherapy and HSCT. Implications for Practice Preliminary evidence is provided for using strength training to enhance early recovery following HSCT. Elastic resistance bands are easy to use and relatively inexpensive. PMID:21116175

Effect of Protein Intake on Strength, Body Composition and Endocrine Changes in Strength/Power Athletes

Directory of Open Access Journals (Sweden)

Kang Jie

2006-12-01

Full Text Available Abstract Comparison of protein intakes on strength, body composition and hormonal changes were examined in 23 experienced collegiate strength/power athletes participating in a 12-week resistance training program. Subjects were stratified into three groups depending upon their daily consumption of protein; below recommended levels (BL; 1.0 – 1.4 g·kg-1·day-1; n = 8, recommended levels (RL; 1.6 – 1.8 g·kg-1·day-1; n = 7 and above recommended levels (AL; > 2.0 g·kg-1·day-1; n = 8. Subjects were assessed for strength [one-repetition maximum (1-RM bench press and squat] and body composition. Resting blood samples were analyzed for total testosterone, cortisol, growth hormone, and insulin-like growth factor. No differences were seen in energy intake (3,171 ± 577 kcal between the groups, and the energy intake for all groups were also below the recommended levels for strength/power athletes. No significant changes were seen in body mass, lean body mass or fat mass in any group. Significant improvements in 1-RM bench press and 1-RM squat were seen in all three groups, however no differences between the groups were observed. Subjects in AL experienced a 22% and 42% greater change in Δ 1-RM squat and Δ 1-RM bench press than subjects in RL, however these differences were not significant. No significant changes were seen in any of the resting hormonal concentrations. The results of this study do not provide support for protein intakes greater than recommended levels in collegiate strength/power athletes for body composition improvements, or alterations in resting hormonal concentrations.

Strength of Ship Stiffened Panels under Combined Loading

DEFF Research Database (Denmark)

Weicheng, Cui; Wang, Young-jun; Pedersen, Preben Terndrup

2000-01-01

A ship's hull is a box girder structure composed of stiffened panels and therefore, strength of stiffened panels plays a significant role for the ultimate strength analysis of ship structures. In recent years several authors have proposed simplified methods to calculate the ultimate strength of s...

High-strength concrete and the design of power plant structures

International Nuclear Information System (INIS)

Puttonen, J.

1991-01-01

Based on the literature, the design of high-strength concrete structures and the suitability of high-strength concrete for the power plant structures have been studied. Concerning the behavior of structures, a basic difference between the high-strength concrete and the traditional one is that the ductility of the high-strength concrete is smaller. In the design, the non-linear stress-strain relationship of the high-strength concrete has to be taken into account. The use of the high-strength concrete is economical if the strength of the material can be utilized. In the long term, the good durability and wear resistance of the high-strength concrete increases the economy of the material. Because of the low permeability of the high-strength concrete, it is a potential material in the safety-related structures of nuclear power plants. The study discovered no particular power plant structure which would always be economical to design of high-strength concrete. However, the high-strength concrete was found to be a competitive material in general

Strengths perspective among the homeless adolescents: A systematic review

Directory of Open Access Journals (Sweden)

Janmejaya Samal

2017-01-01

Full Text Available Background: Earlier, the scholars of family studies have primarily focused on the problems and weaknesses of the families. However, during these days, there is a shift from problems to strength-based perspective. Methodology: Search of literature was carried out through internet-based Google Scholar search engine. Of the 112 titles obtained 21 titles fit the criteria of the study objectives, of which 9 full-text articles were finally selected for the purpose of this review. Results: In this review, nine full-text articles were reviewed. Nine of these researches investigated different facets of strengths perspective among the homeless adolescents. Chronologically, nine of these reviewed studies delineated the following thematic facets of strengths perspective among the homeless adolescents. These include personal strength and informal resources, personal strength in high-risk environment, strengths perspective during the transition of adolescence to adulthood, personal and social strengths that refrained the homeless adolescents form intravenous drug use, resilience and self-esteem, religion as an important strength, “hope” as a way of living among the homeless adolescents, coping strategies of street-involved youth, and usage of internet and social media as an important strength among homeless adolescents. Conclusion: Strengths perspective helps the youth to become a master of their own lives and helps to deal with all the adversities in life.

Creep Strength of Discontinuous Fibre Composites

DEFF Research Database (Denmark)

Pedersen, Ole Bøcker

1974-01-01

relation between stress and strain rate. Expressions for the interface stress, the creep velocity profile adjacent to the fibres and the creep strength of the composite are derived. Previous results for the creep strength, sc = aVfs0 ( \\frac[( Î )\\dot] [( Î )\\dot] 0 )1/nr1 + 1/n c=Vf001n1+1n in which[( Î...... )\\dot] is the composite creep rate,V f is the fibre volume fraction,sgr 0,epsi 0 andn are the constants in the matrix creep law. The creep strength coefficient agr is found to be very weakly dependent onV f and practically independent ofn whenn is greater than about 6....

Attitude Strength.

Science.gov (United States)

Howe, Lauren C; Krosnick, Jon A

2017-01-03

Attitude strength has been the focus of a huge volume of research in psychology and related sciences for decades. The insights offered by this literature have tremendous value for understanding attitude functioning and structure and for the effective application of the attitude concept in applied settings. This is the first Annual Review of Psychology article on the topic, and it offers a review of theory and evidence regarding one of the most researched strength-related attitude features: attitude importance. Personal importance is attached to an attitude when the attitude is perceived to be relevant to self-interest, social identification with reference groups or reference individuals, and values. Attaching personal importance to an attitude causes crystallizing of attitudes (via enhanced resistance to change), effortful gathering and processing of relevant information, accumulation of a large store of well-organized relevant information in long-term memory, enhanced attitude extremity and accessibility, enhanced attitude impact on the regulation of interpersonal attraction, energizing of emotional reactions, and enhanced impact of attitudes on behavioral intentions and action. Thus, important attitudes are real and consequential psychological forces, and their study offers opportunities for addressing behavioral change.

Using Mindfulness-Based Strengths Practices with Gifted Populations

Science.gov (United States)

Sharp, Jennifer E.; Niemiec, Ryan M.; Lawrence, Christopher

2017-01-01

Mindfulness and character strengths are synergistic tools that work together to cultivate well-being. Mindfulness-Based Strengths Practice (MBSP) combines the research and practice of these constructs to enhance well-being, meaning, and engagement. In this article, research supporting how mindfulness and character strengths may benefit the gifted…

The fracture strength by a torsion test at the implant-abutment interface.

Science.gov (United States)

Watanabe, Fumihiko; Hiroyasu, Kazuhiko; Ueda, Kazuhiko

2015-12-01

Fractured connections between implants and implant abutments or abutment screws are frequently encountered in a clinical setting. The purpose of this study was to investigate fracture strength using a torsion test at the interface between the implant and the abutment. Thirty screw-type implant with diameters of 3.3, 3.8, 4.3, 5.0, and 6.0 mm were submitted to a torsion test. Implants of each size were connected to abutments with abutment screws tightened to 20 N · cm. Mechanical stress was applied with a rotational speed of 3.6 °/min until fracture occurred, and maximum torque (fracture torque) and torsional yield strength were measured. The mean values were calculated and then compared using Tukey's test. The abutments were then removed, and the implant-abutment interfaces were examined using a scanning electron microscope (SEM). No significant differences in mean fracture torque were found among 3.3, 3.8, and 4.3 mm-diameter implants, but significant differences were found between these sizes and 5.0 and 6.0 mm-diameter implants (p abutment corresponding to the internal notches of the implant body had been destroyed. Smaller diameter implants demonstrated lower fracture torque and torsional yield strength than implants with larger diameters. In internal tube-in-tube connections, three abutment projections corresponding to rotation-prevention notches were destroyed in each implant.

Predicting vertebral bone strength by vertebral static histomorphometry

DEFF Research Database (Denmark)

Thomsen, Jesper Skovhus; Ebbesen, Ebbe Nils; Mosekilde, Lis

2002-01-01

of the entire vertebral bodies (L-2) were used for histomorphometry. The other iliac crest biopsies and the L-3 were destructively tested by compression. High correlation was found between BV/TV or Tb.Sp and vertebral bone strength (absolute value of r = 0.86 in both cases). Addition of Tb.Th significantly....... No gender-related differences were found in any of the relationships. Neither static histomorphometry nor biomechanical testing of iliac crest bone biopsies is a good predictor of vertebral bone strength.......The study investigates the relationship between static histomorphometry and bone strength of human lumbar vertebral bone. The ability of vertebral histomorphometry to predict vertebral bone strength was compared with that of vertebral densitometry, and also with histomorphometry and bone strength...

Structure and properties during aging of an ultra-high strength Al-Cu-Li-Ag-Mg alloy

Science.gov (United States)

Gayle, Frank W.; Heubaum, Frank H.; Pickens, Joseph R.

1990-01-01

The structure and properties of the strengthening phases formed during aging in an Al-Cu-Li-Ag-Mg alloy (Weldalite 049) were elulcidated, by following the development of the microstructure by means of TEM. The results of observations showed that the Weldalite 049 alloy has a series of unusual and technologically useful combinations of mechanical properties in different aging conditions, such as natural aging without prior cold work to produce high strengths, a reversion temper of lower yield strength and unusually high ductility, a room temperature reaging of the reversion temper eventually leading to the original T4 hardness, and ultrahigh-strength T6 properties.

Influence of processing factors over concrete strength.

Science.gov (United States)

Kara, K. A.; Dolzhenko, A. V.; Zharikov, I. S.

2018-03-01

Construction of facilities of cast in-situ reinforced concrete poses additional requirements to quality of material, peculiarities of the construction process may sometimes lead to appearance of lamination planes and inhomogeneity of concrete, which reduce strength of the material and structure as a whole. Technology compliance while working with cast in-situ concrete has a significant impact onto the concrete strength. Such process factors as concrete curing, vibration and compaction of the concrete mixture, temperature treatment, etc., when they are countered or inadequately followed lead to a significant reduction in concrete strength. Here, the authors experimentally quantitatively determine the loss of strength in in-situ cast concrete structures due to inadequate following of process requirements, in comparison with full compliance.

Strength analysis of PGV-1000M steam generator support

International Nuclear Information System (INIS)

Dubik, Ya.R.; Ageev, S.M.; Orynyak, I.V.; Vasilchenko, B.M.

2017-01-01

The paper presents the design of PGV-1000M steam generator support. It is shown that the load in the rolling support is distributed extremely unevenly, which is associated with the compliance of the support construction. It is demonstrated that under working loads only several rollers are used, the stresses in which exceed the yield strength. This can be an additional loading factor to be considered in the analysis of welding No. 111 failure.

Surface modification of polyethylene by radiation-induced grafting for adhesive bonding. IV. Improvement in wet peel strength

International Nuclear Information System (INIS)

Yamakawa, S.; Yamamoto, F.

1980-01-01

Adhesive joints of hydrolyzed methyl acrylate grafts, bonded with epoxy adhesives, yield extremely high peel strength (adherend failure) in dry conditions. However, when the joints are exposed to humid environments, the peel strength rapidly decreases with exposure time and then reaches a constant value (wet peel strength). Since the locus of failure changes from the adherend to the homopolymer layer with decreasing peel strength, the decrease is due to a decrease in mechanical strength of the homopolymer layer itself, which results from its swelling by water absorption. Many attempts to reduce the swelling of the homopolymer layer or to strengthen the swollen homopolymer layer were unsuccessful except (1) priming with epoxy solutions consisting of a base epoxy resin and organic solvents which can dissolve not only epoxy resins but also hydrolyzed poly(methyl acrylate) and (2) partial etching of the homopolymer layer by photo-oxidative degradation. All the results on the improvement in wet peel strength can be explained in terms of the penetration of epoxy resins into the homopolymer layer and subsequent curing of the penetrated epoxy resin. 15 figures, 1 table

Strength asymmetry of the shoulders in elite volleyball players.

Science.gov (United States)

Hadzic, Vedran; Sattler, Tine; Veselko, Matjaž; Markovic, Goran; Dervisevic, Edvin

2014-01-01

Volleyball players are reported to have shoulder strength imbalances. Previous authors have primarily investigated small samples of male players at a single skill level, without considering playing position, and with inconsistent findings. To evaluate shoulder strength asymmetry and a history of shoulder injury in a large sample of professional volleyball players of both sexes across different playing positions and skill levels. Descriptive laboratory study. A sample of 183 volleyball players (99 men, 84 women). We assessed shoulder internal-rotator and external-rotator concentric strength at 60°/s using an isokinetic dynamometer and dominant-nondominant differences in shoulder strength and strength ratios using repeated-measures analyses of variance. Peak torque was normalized for body mass and external-rotation/internal-rotation concentric strength. Internal-rotation strength was asymmetric in favor of the dominant side in both sexes, regardless of previous shoulder injury status. Male volleyball players had a lower shoulder strength ratio on the dominant side, regardless of previous shoulder injury status. However, this finding was valid only when hand dominance was taken into account. Female volleyball players playing at a higher level (ie, first versus second division) were 3.43 times more likely to have an abnormal strength ratio. Playing position was not associated with an abnormal shoulder strength ratio or strength asymmetry. In male volleyball players, the external-rotation/internal-rotation strength ratio of the dominant shoulder was lower, regardless of playing position, skill level, or a previous shoulder injury. In female players, the ratio was less only in those at a higher skill level. Although speculative, these findings generally suggest that female volleyball players could have a lower risk of developing shoulder-related problems than male volleyball players. Isokinetic shoulder testing may reveal important information about the possible risk

Factors influencing the thermally-induced strength degradation of B/Al composites

International Nuclear Information System (INIS)

Dicarlo, J.A.

1983-01-01

Literature data related to the thermally-induced strength degradation of B/Al composites were examined in the light of fracture theories based on reaction-controlled fiber weakening. Under the assumption of a parabolic time-dependent growth for the interfacial reaction product, a Griffith-type fracture model was found to yield simple equations whose predictions were in good agreement with data for boron fiber average strength and for B/Al axial fracture strain. The only variables in these equations were the time and temperature of the thermal exposure and an empirical factor related to fiber surface smoothness prior to composite consolidation. Such variables as fiber diameter and aluminum alloy composition were found to have little influence. The basic and practical implications of the fracture model equations are discussed

Sources of Life Strengths Appraisal Scale: A Multidimensional Approach to Assessing Older Adults’ Perceived Sources of Life Strengths

Directory of Open Access Journals (Sweden)

Prem S. Fry

2014-01-01

Full Text Available Both cognitive and psychosocial theories of adult development stress the fundamental role of older adults’ appraisals of the diverse sources of cognitive and social-emotional strengths. This study reports the development of a new self-appraisal measure that incorporates key theoretical dimensions of internal and external sources of life strengths, as identified in the gerontological literature. Using a pilot study sample and three other independent samples to examine older adults’ appraisals of their sources of life strengths which helped them in their daily functioning and to combat life challenges, adversity, and losses, a psychometric instrument having appropriate reliability and validity properties was developed. A 24-month followup of a randomly selected sample confirmed that the nine-scale appraisal measure (SLSAS is a promising instrument for appraising older adults’ sources of life strengths in dealing with stresses of daily life’s functioning and also a robust measure for predicting outcomes of resilience, autonomy, and well-being for this age group. A unique strength of the appraisal instrument is its critically relevant features of brevity, simplicity of language, and ease of administration to frail older adults.

Skeletal Geometry and Indices of Bone Strength in Artistic Gymnasts

Science.gov (United States)

Dowthwaite, Jodi N.; Scerpella, Tamara A.

2010-01-01

This review addresses bone geometry and indices of skeletal strength associated with exposure to gymnastic loading during growth. A brief background characterizes artistic gymnastics as a mechanical loading model and outlines densitometric techniques, skeletal outcomes and challenges in assessment of skeletal adaptation. The literature on bone geometric adaptation to gymnastic loading is sparse and consists of results for disparate skeletal sites, maturity phases, gender compositions and assessment methods, complicating synthesis of an overriding view. Furthermore, most studies assess only females, with little information on males and adults. Nonetheless, gymnastic loading during growth appears to yield significant enlargement of total and cortical bone geometry (+10 to 30%) and elevation of trabecular density (+20%) in the forearm, yielding elevated indices of skeletal strength (+20 to +50%). Other sites exhibit more moderate geometric and densitometric adaptations (5 to 15%). Mode of adaptation appears to be site-specific; some sites demonstrate marked periosteal and endosteal expansion, whereas other sites exhibit negligible or moderate periosteal expansion coupled with endocortical contraction. Further research is necessary to address sex-, maturity- and bone tissue-specific adaptation, as well as maintenance of benefits beyond loading cessation. PMID:19949278

optimizing compressive strength characteristics of hollow building

African Journals Online (AJOL)

eobe

Keywords: hollow building Blocks, granite dust, sand, partial replacement, compressive strength. 1. INTRODUCTION ... exposed to extreme climate. The physical ... Sridharan et al [13] conducted shear strength studies on soil-quarry dust.

Strength evaluation of top nozzle holddown spring screw for nuclear fuel assembly

International Nuclear Information System (INIS)

Koh, S. K.; Won, S. Y.; Ryu, C. H.; Kim, Y. J.; Lee, K. S.; Jeon, K. L.

2002-01-01

Holddown springs are required to maintain the nuclear fuel assembly in contact with lower core plate and permit thermal and irradiation-induced length changes. Therefore, the holddown spring screw must be designed such that it is capable of sustaining the loads imposed by the initial tensile preload and operational loads. Prior to assessing the structural integrity of the spring screw in the corrosive and irradiating environment throughout the design lifetime of the fuel assembly, the strength evaluation of screw was made in this paper using the mechanics of materials and finite element methods. Calculations based on the mechanics of materials, showed that the preloaded screw with an operating holddown force had a quite large margin of safety in strength. However, the elastic-plastic finite element analysis showed that the local stresses at the critical regions of head-shank fillet and thread root significantly exceeded than the yield strength of the screw material, resulting in local plastic deformation. Preloading on the screw applied for tightening had beneficial effects on the screw strength by reducing the stress level at the critical regions, compared to the screw without preload. Calculated spring deflection using the finite element analysis was in close agreement with the experimentally measured deflection

Strengthening mechanisms in a high-strength bulk nanostructured Cu–Zn–Al alloy processed via cryomilling and spark plasma sintering

International Nuclear Information System (INIS)

Wen, Haiming; Topping, Troy D.; Isheim, Dieter; Seidman, David N.; Lavernia, Enrique J.

2013-01-01

A bulk nanostructured alloy with the nominal composition Cu–30Zn–0.8Al wt.% (commercial designation brass 260) was fabricated by cryomilling of brass powders and subsequent spark plasma sintering (SPS) of the cryomilled powders, yielding a compressive yield strength of 950 MPa, which is significantly higher than the yield strength of commercial brass 260 alloys (∼200–400 MPa). Transmission electron microscopy investigations revealed that cryomilling results in an average grain diameter of 26 nm and a high density of deformation twins. Nearly fully dense bulk samples were obtained after SPS of cryomilled powders, with average grain diameter 110 nm. After SPS, 10 vol.% of twins is retained with average twin thickness 30 nm. Three-dimensional atom-probe tomography studies demonstrate that the distribution of Al is highly inhomogeneous in the sintered bulk samples, and Al-containing precipitates including Al(Cu,Zn)–O–N, Al–O–N and Al–N are distributed in the matrix. The precipitates have an average diameter of 1.7 nm and a volume fraction of 0.39%. Quantitative calculations were performed for different strengthening contributions in the sintered bulk samples, including grain boundary, twin boundary, precipitate, dislocation and solid-solution strengthening. Results from the analyses demonstrate that precipitate and grain boundary strengthening are the dominant strengthening mechanisms, and the calculated overall yield strength is in reasonable agreement with the experimentally determined compressive yield strength

Estimated strength of shear keys in concrete dams

Energy Technology Data Exchange (ETDEWEB)

Curtis, D.D. [Hatch Energy, Niagara Falls, ON (Canada); Lum, K.K.Y. [BC Hydro, Burnaby, BC (Canada)

2008-07-01

BC Hydro requested that Hatch Energy review the seismic stability of Ruskin Dam which was constructed in 1930 at Hayward Lake in British Columbia. The concrete gravity dam is founded nearly entirely on rock in a narrow valley. The vertical joints between blocks are keyed and grouted. The strength of the shear keys was assessed when a non-linear finite element model found that significant forces were being transferred laterally to the abutments during an earthquake. The lateral transfer of loads to the abutment relies on the strength of the shear keys. The dynamic finite element analysis was used to determine the stability of the dam. A review of the shear strength measurements reported in literature showed that the measurements compared well to those obtained by BC Hydro from cores taken from Ruskin Dam. The cohesive strength obtained using the Griffith failure criteria was also in good agreement with both sets of measurements. A simple ultimate shear strength equation was developed using the Mohr-Coulomb failure criteria to determine combined cohesive and frictional strength of shear keys. Safety factors of 2.0 for static loads and 1.5 for seismic loads were proposed to reduce the ultimate strength to allowable values. It was concluded that given the relatively high shear strength established for the shear keys, the abutment rock or dam/abutment contact will control the amount of load which can arch to the abutments. 8 refs., 4 tabs., 5 figs.

Isometric and isokinetic muscle strength in the upper extremity can be reliably measured in persons with chronic stroke.

Science.gov (United States)

Ekstrand, Elisabeth; Lexell, Jan; Brogårdh, Christina

2015-09-01

To evaluate the test-retest reliability of isometric and isokinetic muscle strength measurements in the upper extremity after stroke. A test-retest design. Forty-five persons with mild to moderate paresis in the upper extremity > 6 months post-stroke. Isometric arm strength (shoulder abduction, elbow flexion), isokinetic arm strength (elbow extension/flexion) and isometric grip strength were measured with electronic dynamometers. Reliability was evaluated with intra-class correlation coefficients (ICC), changes in the mean, standard error of measurements (SEM) and smallest real differences (SRD). Reliability was high (ICCs: 0.92-0.97). The absolute and relative (%) SEM ranged from 2.7 Nm (5.6%) to 3.0 Nm (9.4%) for isometric arm strength, 2.6 Nm (7.4%) to 2.9 Nm (12.6%) for isokinetic arm strength, and 22.3 N (7.6%) to 26.4 N (9.2%) for grip strength. The absolute and relative (%) SRD ranged from 7.5 Nm (15.5%) to 8.4 Nm (26.1%) for isometric arm strength, 7.1 Nm (20.6%) to 8.0 Nm (34.8%) for isokinetic arm strength, and 61.8 N (21.0%) to 73.3 N (25.6%) for grip strength. Muscle strength in the upper extremity can be reliably measured in persons with chronic stroke. Isometric measurements yield smaller measurement errors than isokinetic measurements and might be preferred, but the choice depends on the research question.

High Temperature Strength of Oxide Dispersion Strengthened Aluminium

DEFF Research Database (Denmark)

Clauer, A.H.; Hansen, Niels

1984-01-01

constant (except for the material with the lowest oxide content). The high temperature values of the modulus-corrected yield stresses are approximately two-thirds of the low temperature value. During high temperature creep, there is a definite indication of a threshold stress. This threshold stress......The tensile flow stress of coarse-grained dispersion strengthened Al-Al2O3 materials were measured as a function of temperature (77–873 K) and volume fraction (0.19-0.92 vol.%) of aluminium oxide. For the same material, the creep strength was determined as a function of temperature in the range 573......–873 K. The modulus-corrected yield stress (0.01 offset) is found to be temperature independent at low temperature (195–472 K). Between 473 and 573 K, the yield stress starts to decrease with increasing temperature. At high temperatures (573–873 K), the modulus-corrected yield stress is approximately...

Fatigue testing of weldable high strength steels under simulated service conditions

Science.gov (United States)

Tantbirojn, Natee

There have been concerns over the effect of Cathodic Protection (CP) on weldable high strength steels employed in Jack-up production platform. The guidance provided by the Department of Energy HSE on higher strength steels, based on previous work, was to avoid overprotection as this could cause hydrogen embrittlement. However, the tests conducted so far at UCL for the SE702 type high strength steels (yields strength around 690 MPa) have shown that the effect of over protection on high strength steels may not be as severe as previously thought. For this thesis, SE702 high strength steels have been investigated in more detail. Thick (85mm) parent and ground welded plates were tested under constant amplitude in air and seawater with CP. Tests were also conducted on Thick (40mm) T-butt welded plates under variable amplitude loading in air and seawater with two CP levels (-800mV and -1050mV). Different backing materials (ceramic and metallic) for the welding process of the T-butt plates were also investigated. The variable amplitude sequences employed were generated using the Jack-up Offshore Standard load History (JOSH). The fatigue results are presented as crack growth and S/N curves. They were compared to the conventional offshore steel (BS 4360 50D). The results suggested that the fatigue life of the high strength steels was comparable to the BS 4360 50D steels. The effect of increasing the CP was found to be detrimental to the fatigue life but the effect was not large. The effect of CP was less noticeable in T-butt welded plates. However, in general, the effect of overprotection is not as detrimental to the Jack-up steels as previously thought. The load histories generated by JOSH were found to have some unfavourable characteristics. The framework is based on Markov Chain method and pseudo-random number generator for selecting sea-states. A study was carried out on the sequence generated by JOSH. The generated sequences were analysed for their validity for fatigue

On high temperature strength of carbon steels

International Nuclear Information System (INIS)

Ichinose, Hiroyuki; Tamura, Manabu; Kanero, Takahiro; Ihara, Yoshihito

1977-01-01

In the steels for high temperature use, the oxidation resistance is regarded as important, but carbon steels show enough oxidation resistance to be used continuously at the temperature up to 500 deg. C if the strength is left out of consideration, and up to 450 deg. C even when the strength is taken into account. Moreover, the production is easy, the workability and weldability are good, and the price is cheap in carbon steels as compared with alloy steels. In the boilers for large thermal power stations, 0.15-0.30% C steels are used for reheater tubes, main feed water tubes, steam headers, wall water tubes, economizer tubes, bypass pipings and others, and they account for 70% of all steel materials used for the boilers of 350 MW class and 30% in 1000 MW class. The JIS standard for the carbon steels for high temperature use and the related standards in foreign countries are shown. The high temperature strength of carbon steels changes according to the trace elements, melting and heat treatment as well as the main compositions of C, Si and Mn. Al and N affect the high temperature strength largely. The characteristics of carbon steels after the heating for hours, the factors controlling the microstructure and high temperature strength, and the measures to improve the high temperature strength of carbon steels are explained. (Kako, I.)

Effect of 8 weeks of free-weight and machine-based strength training on strength and power performance.

Science.gov (United States)

Wirth, Klaus; Keiner, Michael; Hartmann, Hagen; Sander, Andre; Mickel, Christoph

2016-12-01

The aim of this study was to evaluate the effectiveness of free-weight and machine-based exercises to increase different strength and speed-strength variables. One hundred twenty male participants (age: 23.8 ± 2.5 years; body height: 181.0 ± 6.8 cm; body mass: 80.2 ± 8.9 kg) joined the study. The 2 experimental groups completed an 8 week periodized strength training program that included 2 training sessions per week. The exercises that were used in the strength training programs were the parallel barbell squat and the leg press. Before and after the training period, the 1-repetition-maximum in the barbell squat and the leg press, the squat jump, the countermovement jump and unilateral isometric force (maximal isometric force and the rate of force development) were evaluated. To compare each group pre vs. post-intervention, analysis of variance with repeated measures and Scheffé post-hoc tests were used. The leg press group increased their 1-repetition-maximum significantly (p squat group such variables as 1-repetition-maximum, the squat jump and the countermovement jump increased significantly (p squat group even showed a statistically significant decrease. Differences between the 2 experimental groups were detected for the squat jump and the countermovement jump. In comparison with the leg press, the squat might be a better strength training exercise for the development of jump performance.

Grip Strength Survey Based on Hand Tool Usage

Directory of Open Access Journals (Sweden)

Erman ÇAKIT

2016-12-01

Full Text Available Hand grip strength is broadly used for performing tasks involving equipment in production and processing activities. Most professionals in this field rely on grip strength to perform their tasks. There were three main aims of this study: i determining various hand grip strength measurements for the group of hand tool users, ii investigating the effects of height, weight, age, hand dominance, body mass index, previous Cumulative Trauma Disorder (CTD diagnosis, and hand tool usage experience on hand grip strength, and iii comparing the obtained results with existing data for other populations. The study groups comprised 71 healthy male facility workers. The values of subjects’ ages was observed between 26 and 74 years. The data were statistically analyzed to assess the normality of data and the percentile values of grip strength. The results of this study demonstrate that there were no significance differences noted between dominant and non-dominant hands. However, there were highly significant differences between the CTD group and the other group. Hand grip strength for the dominant hand was positively correlated to height, weight, and body mass index, and negatively correlated to age and tool usage experience. Hand dominance, height, weight, body mass index, age and tool usage experience should be considered when establishing normal values for grip strength.

Tailored Welding Technique for High Strength Al-Cu Alloy for Higher Mechanical Properties

Science.gov (United States)

Biradar, N. S.; Raman, R.

AA2014 aluminum alloy, with 4.5% Cu as major alloying element, offers highest strength and hardness values in T6 temper and finds extensive use in aircraft primary structures. However, this alloy is difficult to weld by fusion welding because the dendritic structure formed can affect weld properties seriously. Among the welding processes, AC-TIG technique is largely used for welding. As welded yield strength was in the range of 190-195 MPa, using conventional TIG technique. Welding metallurgy of AA2014 was critically reviewed and factors responsible for lower properties were identified. Square-wave AC TIG with Transverse mechanical arc oscillation (TMAO) was postulated to improve the weld strength. A systematic experimentation using 4 mm thick plates produced YS in the range of 230-240 MPa, has been achieved. Through characterization including optical and SEM/EDX was conducted to validate the metallurgical phenomena attributable to improvement in weld properties.

Improving body composition and strength in athletes through a 4-month combined martial arts and strength training program

Directory of Open Access Journals (Sweden)

Aleksandra Stachoń

2016-06-01

2Zakład Sportów Indywidualnych, Akademia Wychowania Fizycznego, ul. Paderewskiego 35, Wrocław       Corresponding author: Dr Aleksandra Jadwiga Stachoń, e-mail: aleksandra.stachon@awf.wroc.pl Departament of Physical Anthropology, University School of Physical Education in Wrocław, al. I.J. Paderewskiego 35, bud. P2, 51-612 Wrocław; Poland Phone: 71 347 33 44         Key words: resistance training, body build, body composition, combat sport.   Abstract Background and aim. Body composition is one of key components of health in both general and athletic populations. In martial arts great significance is attached to the development of mesomorphy and strength, which are crucial for performing offensive and defensive actions during fights. The study proposes to introduce progressive strength training programme - arranged primarily for beginners – in order to improve body composition of non-elite male martial arts competitors. The present study aims to evaluate the changes in body massiveness, body composition and strength in 31 martial arts practitioners from academic sports clubs after a combined martial arts and strength training programme. Material and methods. The 16-week intervention was based on a targeted progressive resistance training protocol developed by Stefaniak [1995]. The anthropometric, physical and motoric measurements were performed twice at four months interval. This programme includes training three times weekly with increased number of repetitions (19-24, number of sets (1-3 and increased loads (5%. Results. After the completion of the training program, significant increase for about 1.8 kgin body mass was observed. Body massiveness (BMI increased from 23.2 ± 1.8 kg/m2 to 23.9 ± 1.8 kg/m2. The analysis using Sheldon’s somatotypes revealed an increase of mesomorphy (from 5.5 to 5.7 and decrease of ectomorphy (from 2.5 to 2.4. The level of endomorphy became stable (2.1. The maximal circumferences of flexed arm, forearm, calf and

Factors influencing the creep strength of hot pressed beryllium

International Nuclear Information System (INIS)

Webster, D.; Crooks, D.D.

1975-01-01

The parameters controlling the creep strength of hot pressed beryllium block have been determined. Creep strength was improved by a high initial dislocation density, a coarse grain size, and a low impurity content. The impurities most detrimental to creep strength were found to be aluminum, magnesium, and silicon. A uniform distribution of BeO was found to give creep strength which was inferior to a grain boundary distribution. The creep strength of very high purity, hot isostatically pressed beryllium was found to compare favorably with that of other more commonly used high temperature metals

Strength and failure modes of ceramic multilayers

DEFF Research Database (Denmark)

Sørensen, Bent F.; Toftegaard, Helmuth Langmaack; Linderoth, Søren

2012-01-01

A model was developed for the prediction of the tensile strength of thin, symmetric 3-layer sandwich specimens. The model predictions rationalize the effect of heat-treatment temperature on the strength of sandwich specimens consisting of an YSZ (Yttria-Stabilized Zirconia) substrate coated with ...... and propagating into the substrate. These predictions are consistent with microstructural observations of the fracture surfaces. A good agreement was found between the measured strength values and model predictions. © 2012 Elsevier Ltd. All rights reserved....

Fabrication and heat treatment of high strength Al-Cu-Mg alloy processed using selective laser melting

Science.gov (United States)

Zhang, Hu; Zhu, Haihong; Nie, Xiaojia; Qi, Ting; Hu, Zhiheng; Zeng, Xiaoyan

2016-04-01

The proposed paper illustrates the fabrication and heat treatment of high strength Al-Cu-Mg alloy produced by selective laser melting (SLM) process. Al-Cu-Mg alloy is one of the heat treatable aluminum alloys regarded as difficult to fusion weld. SLM is an additive manufacturing technique through which components are built by selectively melting powder layers with a focused laser beam. The process is characterized by short laser-powder interaction times and localized high heat input, which leads to steep thermal gradients, rapid solidification and fast cooling. In this research, 3D Al-Cu-Mg parts with relative high density of 99.8% are produced by SLM from gas atomized powders. Room temperature tensile tests reveal a remarkable mechanical behavior: the samples show yield and tensile strengths of about 276 MPa and 402 MPa, respectively, along with fracture strain of 6%. The effect of solution treatment on microstructure and related tensile properties is examined and the results demonstrate that the mechanical behavior of the SLMed Al-Cu-Mg samples can be greatly enhanced through proper heat treatment. After T4 solution treatment at 540°C, under the effect of precipitation strengthening, the tensile strength and the yield strength increase to 532 MPa and 338 MPa, respectively, and the elongation increases to 13%.

Response surface optimization of pH and ionic strength for emulsion characteristics of egg yolk.

Science.gov (United States)

Kurt, S; Zorba, O

2009-11-01

Effects of pH (3.5, 4.5, 6.0, 7.5, and 8.5) and ionic strength (0.05, 0.15, 0.30, 0.45, and 0.55 M NaCl) on emulsion capacity, emulsion stability (ES), apparent yield stress of emulsion (AYS), and emulsion density (ED) of egg yolk were studied by using a model system. Ionic strength and pH had significant (P emulsion characteristics of egg yolk. Their interaction effects also have been found significant on ES, AYS, and ED. Predicted solutions of ES, emulsion capacity, and ED were minimum. The critical point of ES was determined to be at pH 6.08 and an ionic strength of 0.49 (M NaCl). Predicted solution for AYS was a maximum, which was determined to be at pH 6.04 and an ionic strength of 0.29 (M NaCl). Optimum values of pH and ionic strenght were 4.61 to 7.43 and 0.10 to 0.47, respectively.

Tensile rock mass strength estimated using InSAR

KAUST Repository

Jonsson, Sigurjon

2012-11-01

The large-scale strength of rock is known to be lower than the strength determined from small-scale samples in the laboratory. However, it is not well known how strength scales with sample size. I estimate kilometer-scale tensional rock mass strength by measuring offsets across new tensional fractures (joints), formed above a shallow magmatic dike intrusion in western Arabia in 2009. I use satellite radar observations to derive 3D ground displacements and by quantifying the extension accommodated by the joints and the maximum extension that did not result in a fracture, I put bounds on the joint initiation threshold of the surface rocks. The results indicate that the kilometer-scale tensile strength of the granitic rock mass is 1–3 MPa, almost an order of magnitude lower than typical laboratory values.

Tensile rock mass strength estimated using InSAR

KAUST Repository

Jonsson, Sigurjon

2012-01-01

The large-scale strength of rock is known to be lower than the strength determined from small-scale samples in the laboratory. However, it is not well known how strength scales with sample size. I estimate kilometer-scale tensional rock mass strength by measuring offsets across new tensional fractures (joints), formed above a shallow magmatic dike intrusion in western Arabia in 2009. I use satellite radar observations to derive 3D ground displacements and by quantifying the extension accommodated by the joints and the maximum extension that did not result in a fracture, I put bounds on the joint initiation threshold of the surface rocks. The results indicate that the kilometer-scale tensile strength of the granitic rock mass is 1–3 MPa, almost an order of magnitude lower than typical laboratory values.

Effect of Seed Orientation and Medium Strength on In vitro Germination of Pterocarpus marsupium Roxb.

Directory of Open Access Journals (Sweden)

Yogeshwar MISHRA

2013-12-01

Full Text Available A method was developed for optimization of In vitro germination of an economically important timber-yielding multipurpose tree, Pterocarpus marsupium Roxb. The seeds inoculated in different orientation on different strengths of MS medium without any hormones showed varied response to the seed positions. The seeds inoculated on half strength medium in horizontal position recorded to produce a maximum germination (78.23%, shoot number (0.86 and root number (7.99. However, a maximum of shoot length of 3.67 cm was recorded in the quarter strength medium in the seeds inoculated in vertical down position, which was significantly higher than other media strength and positions. Our results indicate that the seed orientation including medium strength have tremendous effect on germination and seeds inoculated horizontally on half strength MS medium can be utilized to enhance In vitro seed germination of Pterocarpus marsupium.

High strength nanostructured Al-based alloys through optimized processing of rapidly quenched amorphous precursors.

Science.gov (United States)

Kim, Song-Yi; Lee, Gwang-Yeob; Park, Gyu-Hyeon; Kim, Hyeon-Ah; Lee, A-Young; Scudino, Sergio; Prashanth, Konda Gokuldoss; Kim, Do-Hyang; Eckert, Jürgen; Lee, Min-Ha

2018-01-18

We report the methods increasing both strength and ductility of aluminum alloys transformed from amorphous precursor. The mechanical properties of bulk samples produced by spark-plasma sintering (SPS) of amorphous Al-Ni-Co-Dy powders at temperatures above 673 K are significantly enhanced by in-situ crystallization of nano-scale intermetallic compounds during the SPS process. The spark plasma sintered Al 84 Ni 7 Co 3 Dy 6 bulk specimens exhibit 1433 MPa compressive yield strength and 1773 MPa maximum strength together with 5.6% plastic strain, respectively. The addition of Dy enhances the thermal stability of primary fcc Al in the amorphous Al-TM -RE alloy. The precipitation of intermetallic phases by crystallization of the remaining amorphous matrix plays important role to restrict the growth of the fcc Al phase and contributes to the improvement of the mechanical properties. Such fully crystalline nano- or ultrafine-scale Al-Ni-Co-Dy systems are considered promising for industrial application because their superior mechanical properties in terms of a combination of very high room temperature strength combined with good ductility.

Strength through structure: visualization and local assessment of the trabecular bone structure

International Nuclear Information System (INIS)

Raeth, C; Monetti, R; Bauer, J; Sidorenko, I; Mueller, D; Matsuura, M; Lochmueller, E-M; Zysset, P; Eckstein, F

2008-01-01

The visualization and subsequent assessment of the inner human bone structures play an important role for better understanding the disease- or drug-induced changes of bone in the context of osteoporosis giving prospect for better predictions of bone strength and thus of the fracture risk of osteoporotic patients. In this work, we show how the complex trabecular bone structure can be visualized using μCT imaging techniques at an isotropic resolution of 26 μm. We quantify these structures by calculating global and local topological and morphological measures, namely Minkowski functionals (MFs) and utilizing the (an-)isotropic scaling index method (SIM) and by deriving suitable texture measures based on MF and SIM. Using a sample of 151 specimens taken from human vertebrae in vitro, we correlate the texture measures with the mechanically measured maximum compressive strength (MCS), which quantifies the strength of the bone probe, by using Pearson's correlation coefficient. The structure parameters derived from the local measures yield good correlations with the bone strength as measured in mechanical tests. We investigate whether the performance of the texture measures depends on the MCS value by selecting different subsamples according to MCS. Considering the whole sample the results for the newly defined parameters are better than those obtained for the standard global histomorphometric parameters except for bone volume/total volume (BV/TV). If a subsample consisting only of weak bones is analysed, the local structural analysis leads to similar and even better correlations with MCS as compared to BV/TV. Thus, the MF and SIM yield additional information about the stability of the bone especially in the case of weak bones, which corroborates the hypothesis that the bone structure (and not only its mineral mass) constitutes an important component of bone stability.

Generalization of the existing relations between microstructure and yield stress from ferrite-pearlite to high strength steels

Energy Technology Data Exchange (ETDEWEB)

Iza-Mendia, A., E-mail: aiza@ceit.es [CEIT and Tecnun (University of Navarra), Manuel de Lardizabal 15, 20018 Donostia-San Sebastian, Basque Country (Spain); Gutierrez, I. [CEIT and Tecnun (University of Navarra), Manuel de Lardizabal 15, 20018 Donostia-San Sebastian, Basque Country (Spain)

2013-01-20

A series of available equations allows the yield and the tensile strength of low carbon ferrite-pearlite microstructures to be expressed as a function of the optical grain size, steel composition and interstitials in solution. Over the years, as the complexity of steel microstructures has increased, some additional terms have been added to account for precipitation and forest dislocation contributions. In theory, this opens the door for an extension of these equations to bainitic microstructures. Nevertheless, there is a series of difficulties that needs to be overcome in order to improve prediction accuracy. In the present work, different microstructures (ferrite-pearlite, bainite, quenched, and quenched and tempered) were produced and tension tested in a C-Mn-Nb steel. Optical microscopy and EBSD (Electron Back Scattered Diffraction) were applied and the results were compared as a function of the tolerance angle. Based on this work, an adaptation to Pickering's equation is proposed, including its extension to other microstructures rather than ferrite-pearlite.

Personality Typology in Relation to Muscle Strength

Science.gov (United States)

Terracciano, Antonio; Milaneschi, Yuri; Metter, E. Jeffrey; Ferrucci, Luigi

2011-01-01

Background Physical inactivity plays a central role in the age-related decline in muscle strength, an important component in the process leading to disability. Personality, a significant determinant of health behaviors including physical activity, could therefore impact muscle strength throughout adulthood and affect the rate of muscle strength decline with aging. Personality typologies combining “high neuroticism” (N≥55), “low extraversion” (Epersonality types. Facet analyses suggest an important role for the N components of depression and hostility. Physical activity level appears to partly explain some of these associations. Conclusion Findings provide support for the notion that the typological approach to personality may be useful in identifying specific personality types at risk of low muscle strength and offer the possibility for more targeted prevention and intervention programs. PMID:21614452

Corium crust strength measurements

Energy Technology Data Exchange (ETDEWEB)

Lomperski, S. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439-4840 (United States)], E-mail: lomperski@anl.gov; Farmer, M.T. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439-4840 (United States)], E-mail: farmer@anl.gov

2009-11-15

Corium strength is of interest in the context of a severe reactor accident in which molten core material melts through the reactor vessel and collects on the containment basemat. Some accident management strategies involve pouring water over the melt to solidify it and halt corium/concrete interactions. The effectiveness of this method could be influenced by the strength of the corium crust at the interface between the melt and coolant. A strong, coherent crust anchored to the containment walls could allow the yet-molten corium to fall away from the crust as it erodes the basemat, thereby thermally decoupling the melt from the coolant and sharply reducing the cooling rate. This paper presents a diverse collection of measurements of the mechanical strength of corium. The data is based on load tests of corium samples in three different contexts: (1) small blocks cut from the debris of the large-scale MACE experiments, (2) 30 cm-diameter, 75 kg ingots produced by SSWICS quench tests, and (3) high temperature crusts loaded during large-scale corium/concrete interaction (CCI) tests. In every case the corium consisted of varying proportions of UO{sub 2}, ZrO{sub 2}, and the constituents of concrete to represent a LWR melt at different stages of a molten core/concrete interaction. The collection of data was used to assess the strength and stability of an anchored, plant-scale crust. The results indicate that such a crust is likely to be too weak to support itself above the melt. It is therefore improbable that an anchored crust configuration could persist and the melt become thermally decoupled from the water layer to restrict cooling and prolong an attack of the reactor cavity concrete.

Importance of Tensile Strength on the Shear Behavior of Discontinuities

Science.gov (United States)

Ghazvinian, A. H.; Azinfar, M. J.; Geranmayeh Vaneghi, R.

2012-05-01

In this study, the shear behavior of discontinuities possessing two different rock wall types with distinct separate compressive strengths was investigated. The designed profiles consisted of regular artificial joints molded by five types of plaster mortars, each representing a distinct uniaxial compressive strength. The compressive strengths of plaster specimens ranged from 5.9 to 19.5 MPa. These specimens were molded considering a regular triangular asperity profile and were designed so as to achieve joint walls with different strength material combinations. The results showed that the shear behavior of discontinuities possessing different joint wall compressive strengths (DDJCS) tested under constant normal load (CNL) conditions is the same as those possessing identical joint wall strengths, but the shear strength of DDJCS is governed by minor joint wall compressive strength. In addition, it was measured that the predicted values obtained by Barton's empirical criterion are greater than the experimental results. The finding indicates that there is a correlation between the joint roughness coefficient (JRC), normal stress, and mechanical strength. It was observed that the mode of failure of asperities is either pure tensile, pure shear, or a combination of both. Therefore, Barton's strength criterion, which considers the compressive strength of joint walls, was modified by substituting the compressive strength with the tensile strength. The validity of the modified criterion was examined by the comparison of the predicted shear values with the laboratory shear test results reported by Grasselli (Ph.D. thesis n.2404, Civil Engineering Department, EPFL, Lausanne, Switzerland, 2001). These comparisons infer that the modified criterion can predict the shear strength of joints more precisely.

Maximal Strength Testing in Healthy Children.

Science.gov (United States)

Faigenbaum, Avery D.; Milliken, Laurie A.; Westcott, Wayne L.

2003-01-01

Evaluated the safety and efficacy of 1 repetition maximum (1RM) strength testing in healthy children age 6-12 years. Data were collected on 96 children who performed a 1RM test on one upper body and one lower body exercise using child-sized weight machines. Findings indicated that children could safely perform 1RM strength tests provided…

Comparison of Post Weld Treatment of High Strength Steel Welded Joints in Medium Cycle Fatigue

DEFF Research Database (Denmark)

Pedersen, Mikkel Melters; Mouritsen, Ole Ø.; Hansen, Michael Rygaard

2010-01-01

This paper presents a comparison of three post-weld treatments for fatigue life improvement of welded joints. The objective is to determine the most suitable post-weld treatment for implementation in mass production of certain crane components manufactured from very high-strength steel...... the stress range can exceed the yield-strength of ordinary structural steel, especially when considering positive stress ratios (R > 0). Fatigue experiments and qualitative evaluation of the different post-weld treatments leads to the selection of TIG dressing. The process of implementing TIG dressing...... in mass production and some inherent initial problems are discussed. The treatment of a few critical welds leads to a significant increase in fatigue performance of the entire structure and the possibility for better utilization of very high-strength steel....

A NEW CLINICAL MUSCLE FUNCTION TEST FOR ASSESSMENT OF HIP EXTERNAL ROTATION STRENGTH: AUGUSTSSON STRENGTH TEST.

Science.gov (United States)

Augustsson, Jesper

2016-08-01

Dynamic clinical tests of hip strength applicable on patients, non-athletes and athletes alike, are lacking. The aim of this study was therefore to develop and evaluate the reliability of a dynamic muscle function test of hip external rotation strength, using a novel device. A second aim was to determine if gender differences exist in absolute and relative hip strength using the new test. Fifty-three healthy sport science students (34 women and 19 men) were tested for hip external rotation strength using a device that consisted of a strap connected in series with an elastic resistance band loop, and a measuring tape connected in parallel with the elastic resistance band. The test was carried out with the subject side lying, positioned in 45 ° of hip flexion and the knees flexed to 90 ° with the device firmly fastened proximally across the knees. The subject then exerted maximal concentric hip external rotation force against the device thereby extending the elastic resistance band. The displacement achieved by the subject was documented by the tape measure and the corresponding force production was calculated. Both right and left hip strength was measured. Fifteen of the subjects were tested on repeated occasions to evaluate test-retest reliability. No significant test-retest differences were observed. Intra-class correlation coefficients ranged 0.93-0.94 and coefficients of variation 2.76-4.60%. In absolute values, men were significantly stronger in hip external rotation than women (right side 13.2 vs 11.0 kg, p = 0.001, left side 13.2 vs 11.5 kg, p = 0.002). There were no significant differences in hip external rotation strength normalized for body weight (BW) between men and women (right side 0.17 kg/BW vs 0.17 kg/BW, p = 0.675, left side 0.17 kg/BW vs 0.18 kg/BW, p = 0.156). The new muscle function test showed high reliability and thus could be useful for measuring dynamic hip external rotation strength in patients, non-athletes and athletes

Measures of Strength and Fitness for Older Populations.

Science.gov (United States)

Osness, Wayne H.; Hiebert, Lujean M.

The overall strength of the musculature does not require testing of large numbers of muscle groups and can be accomplished from three or four tests. Small batteries of strength tests have been devised to predict total strength. The best combination of tests for males are thigh flexors, leg extensors, arm flexors, and pectoralis major. The battery…

Johnson-Cook Strength Model Constants for VascoMax 300 and 1080 Steels

International Nuclear Information System (INIS)

Cinnamon, J. D.; Palazotto, A. N.; Kennan, Z.; Brar, N. S.; Bajaj, D.

2006-01-01

High strength steels, VascoMax 300 and 1080, are characterized under tension at strain rates of ∼1/s, ∼500/s, ∼1000/s, and ∼1500/s and at high temperatures using the quasi-static and split Hopkinson bar techniques. The data on 1080 steel exhibited a typical strain hardening response, whereas Vasco-Max 300 steel showed diminishing flow stress beyond yielding because of localized necking in gauge section of the tested specimens. The tension data are analyzed to determine the Johnson-Cook (J-C) strength model constants for the two steels. The flow stress values for VascoMax are adjusted to account for necking, and the corrected J-C model is developed

In vitro evaluation of repair bond strength of composite: Effect of surface treatments with bur and laser and application of universal adhesive.

Science.gov (United States)

Kiomarsi, Nazanin; Espahbodi, Melika; Chiniforush, Nasim; Karazifard, Mohammad Javd; Kamangar, Sedighe Sadat Hashemi

2017-09-30

This study aimed to assess the effect of surface treatment by bur and laser and application of universal adhesive on repair bond strength of composite resin. A total of 120 composite blocks measuring 6×4×4 mm were fabricated of Filtek Z250 composite. All samples were subjected to 5,000 thermal cycles and divided into two groups for surface preparation by bur and by Er,Cr:YSGG laser (n = 60). The surfaces were then etched with orthophosphoric acid, rinsed with water and divided into three groups (silane, silane plus Single Bond and silane plus Single Bond Universal). Repair composite was then bonded to aged composite. Half of the samples in each group were stored in distilled water at 37°C for 24 hours and the other half underwent 5000 thermal cycles. All samples were then subjected to shear bond strength testing using a universal testing machine at a crosshead speed of 1 mm/minute. The data were analyzed using one-way ANOVA and Tukey's HSD test. Mode of failure was determined using a stereomicroscope. Bur preparation plus universal adhesive yielded the highest bond strength (30.16 µ 2.26 MPa). Laser plus silane yielded the lowest bond strength (5.63 µ 2.43 MPa). Bur preparation yielded significantly higher bond strength than laser (P composite by bur and application of universal adhesive can improve the repair bond strength of composite. Application of silane (without adhesive) in the process of repair cannot provide adequately high repair bond strength.

Neutron source strength associated with FTR fuel

International Nuclear Information System (INIS)

Boroughs, G.L.; Bunch, W.L.; Johnson, D.L.

1975-01-01

The study presented shows the important effect of shelf life on the neutron source strength anticipated from fuel irradiated in the FTR. The neutron source strength will be enhanced appreciably by extended shelf lives. High neutron source strengths will also be associated with reprocessed LWR plutonium, which is expected to contain a greater abundance of the higher isotopes. The branching ratio and cross section of 241 Am is an important parameter that needs to be defined more precisely to establish calculated values with greater precision

Hip adduction and abduction strength profiles in elite soccer players

DEFF Research Database (Denmark)

Thorborg, Kristian; Serner, Andreas; Petersen, Jesper

2011-01-01

An ipsilateral hip adduction/abduction strength ratio of more than 90%, and hip adduction strength equal to that of the contralateral side have been suggested to clinically represent adequate strength recovery of hip adduction strength in athletes after groin injury. However, to what extent side-......-to-side symmetry in isometric hip adduction and abduction strength can be assumed in soccer players remains uncertain....

Comparison of Open-Hole Compression Strength and Compression After Impact Strength on Carbon Fiber/Epoxy Laminates for the Ares I Composite Interstage

Science.gov (United States)

Hodge, Andrew J.; Nettles, Alan T.; Jackson, Justin R.

2011-01-01

Notched (open hole) composite laminates were tested in compression. The effect on strength of various sizes of through holes was examined. Results were compared to the average stress criterion model. Additionally, laminated sandwich structures were damaged from low-velocity impact with various impact energy levels and different impactor geometries. The compression strength relative to damage size was compared to the notched compression result strength. Open-hole compression strength was found to provide a reasonable bound on compression after impact.

Elastic buckling strength of corroded steel plates

Indian Academy of Sciences (India)

structural safety assessment of corroded structures, residual strength should be ... Rahbar-Ranji (2001) has proposed a spectrum for random simulation of ... The main aim of the present work is to investigate the buckling strength of simply ...

Evidence for a weakening strength of temperature-corn yield relation in the United States during 1980–2010

Energy Technology Data Exchange (ETDEWEB)

Leng, Guoyong

2017-12-01

Temperature is known to be correlated with crop yields, causing reduction of crop yield with climate warming without adaptations or CO2 fertilization effects. The historical temperature-crop yield relation has often been used for informing future changes. This relationship, however, may change over time following alternations in other environmental factors. Results show that the strength of the relationship between the interannual variability of growing season temperature and corn yield (RGST_CY) has declined in the United States between 1980 and 2010 with a loss in the statistical significance. The regression slope which represents the anomalies in corn yield that occur in association with 1 degree temperature anomaly has decreased significantly from -6.9%/K of the first half period to -2.4%/K~-3.5%/K of the second half period. This implies that projected corn yield reduction will be overestimated by a fact of 2 in a given warming scenario, if the corn-temperature relation is derived from the earlier historical period. Changes in RGST_CY are mainly observed in Midwest Corn Belt and central High Plains, and are well reproduced by 11 process-based crop models. In Midwest rain-fed systems, the decrease of negative temperature effects coincides with an increase in water availability by precipitation. In irrigated areas where water stress is minimized, the decline of beneficial temperature effects is significantly related to the increase in extreme hot days. The results indicate that an extrapolation of historical yield response to temperature may bias the assessment of agriculture vulnerability to climate change. Efforts to reduce climate impacts on agriculture should pay attention not only to climate change, but also to changes in climate-crop yield relations. There are some caveats that should be acknowledged as the analysis is restricted to the changes in the linear relation between growing season mean temperature and corn yield for the specific study period.

Character strengths, social anxiety, and physiological stress reactivity

Directory of Open Access Journals (Sweden)

Tingting Li

2017-05-01

Full Text Available In this paper, the effects of character strengths on the physiological reactivity to social anxiety induced by the Trier Social Stress Task were reported. On the basis of their scores in the Chinese Virtues Questionnaire, 30 college students were assigned to either high- (n = 15 or low-character-strength (n = 15 groups. Their psychological stress and physiological data across three laboratory stages (namely, baseline, stress exposure, and post-stress were collected. Results indicated that individuals with high character strengths exhibited rapid cardiovascular recovery from baseline to post-stress even if high- and low-character-strength groups showed similar patterns of cardiovascular arousal in response to the stress at baseline and stress exposure. These results prove that character strengths are stress-defense factors that allow for psychological and physiological adaptation to stress.

A three-dimensional computerized isometric strength measurement system.

Science.gov (United States)

Black, Nancy L; Das, Biman

2007-05-01

The three-dimensional Computerized Isometric Strength Measurement System (CISMS) reliably and accurately measures isometric pull and push strengths in work spaces of paraplegic populations while anticipating comparative studies with other populations. The main elements of the system were: an extendable arm, a vertical supporting track, a rotating platform, a force transducer, stability sensors and a computerized data collection interface. The CISMS with minor modification was successfully used to measure isometric push-up and pull-down strengths of paraplegics and isometric push, pull, push-up and pull-down strength in work spaces for seated and standing able-bodied populations. The instrument has satisfied criteria of versatility, safety and comfort, ease of operation, and durability. Results are accurate within 2N for aligned forces. Costing approximately $1,500 (US) including computer, the system is affordable and accurate for aligned isometric strength measurements.

The List-Strength Effect in Recall: Relative-Strength Competition and Retrieval Inhibition May both Contribute to Forgetting

Science.gov (United States)

Verde, Michael F.

2009-01-01

According to the principle of relative-strength competition, stronger items in memory block the retrieval of weaker items. This principle, integral to many theories of forgetting over the years, derives much of its support from the list-strength effect (LSE), in which strengthening some items in a study list makes it more difficult to recall other…

Statistical Analysis Of Failure Strength Of Material Using Weibull Distribution

International Nuclear Information System (INIS)

Entin Hartini; Mike Susmikanti; Antonius Sitompul

2008-01-01

In evaluation of ceramic and glass materials strength a statistical approach is necessary Strength of ceramic and glass depend on its measure and size distribution of flaws in these material. The distribution of strength for ductile material is narrow and close to a Gaussian distribution while strength of brittle materials as ceramic and glass following Weibull distribution. The Weibull distribution is an indicator of the failure of material strength resulting from a distribution of flaw size. In this paper, cumulative probability of material strength to failure probability, cumulative probability of failure versus fracture stress and cumulative probability of reliability of material were calculated. Statistical criteria calculation supporting strength analysis of Silicon Nitride material were done utilizing MATLAB. (author)

High strength H2S resistant steels and alloys for oil field tubular products

International Nuclear Information System (INIS)

Straatmann, J.A.; Grobner, P.J.

1976-01-01

New sources of oil and natural gas are more frequently occurring at greater depths in hostile surface and underground environments. The materials utilized in drilling and completing the wells require higher strength along with improved resistance to corrosive/embrittling attack by contaminants present in the deep, high pressure-high temperature formations. Higher strength steels having yield strengths in excess of 690 MPa and possessing improved resistance to sulfide stress corrosion cracking (SSC) have been developed and are currently being evaluated by the oil industry. The research to develop these new steels combined modifications of chemical compositions, heat treatment and processing variables. For most severe SSC environments and deep wells, it was necessary to provide even better alloys for tubular materials. The successful solution to the problem was found with the utilization of nickel-base alloys. These materials are being evaluated in commercial applications

Gluebond strength of laser cut wood

Science.gov (United States)

Charles W. McMillin; Henry A. Huber

1985-01-01

The degree of strength loss when gluing laser cut wood as compared to conventionally sawn wood and the amount of additional surface treatment needed to improve bond quality were assessed under normal furniture plant operating conditions. The strength of laser cut oak glued with polyvinyl acetate adhesive was reduced to 75 percent of sawn joints and gum was reduced 43...

Residual-strength determination in polymetric materials

Energy Technology Data Exchange (ETDEWEB)

Christensen, R.M.

1981-10-01

Kinetic theory of crack growth is used to predict the residual strength of polymetric materials acted upon by a previous history. Specifically, the kinetic theory is used to characterize the state of growing damage that occurs under a constant-stress (load) state. The load is removed before failure under creep-rupture conditions, and the residual instantaneous strength is determined from the theory by taking account of the damage accumulation under the preceding constant-load history. The rate of change of residual strength is found to be strongest when the duration of the preceding load history is near the ultimate lifetime under that condition. Physical explanations for this effect are given, as are numerical examples. Also, the theoretical prediction is compared with experimental data.

Residual-strength determination in polymetric materials

International Nuclear Information System (INIS)

Christensen, R.M.

1981-01-01

Kinetic theory of crack growth is used to predict the residual strength of polymetric materials acted upon by a previous history. Specifically, the kinetic theory is used to characterize the state of growing damage that occurs under a constant-stress (load) state. The load is removed before failure under creep-rupture conditions, and the residual instantaneous strength is determined from the theory by taking account of the damage accumulation under the preceding constant-load history. The rate of change of residual strength is found to be strongest when the duration of the preceding load history is near the ultimate lifetime under that condition. Physical explanations for this effect are given, as are numerical examples. Also, the theoretical prediction is compared with experimental data

Strength properties of concrete at elevated temperatures

International Nuclear Information System (INIS)

Freskakis, G.N.; Burrow, R.C.; Debbas, E.B.

1979-01-01

A study is presented concerning the compressive strength, modulus of elasticity, and stress-strain relationships of concrete at elevated temperatures. A review of published results provides information for the development of upper and lower bound relationships for compressive strength and the modulus of elasticity and establishes exposure conditions for a lower bound thermal response. The relationships developed from the literature review are confirmed by the results of a verification test program. The strength and elasticity relationships provide a basis for the development of design stress-strain curves for concrete exposed to elevated temperatures

Strength training for the warfighter.

Science.gov (United States)

Kraemer, William J; Szivak, Tunde K

2012-07-01

Optimizing strength training for the warfighter is challenged by past training philosophies that no longer serve the modern warfighter facing the "anaerobic battlefield." Training approaches for integration of strength with other needed physical capabilities have been shown to require a periodization model that has the flexibility for changes and is able to adapt to ever-changing circumstances affecting the quality of workouts. Additionally, sequencing of workouts to limit over-reaching and development of overtraining syndromes that end in loss of duty time and injury are paramount to long-term success. Allowing adequate time for rest and recovery and recognizing the negative influences of extreme exercise programs and excessive endurance training will be vital in moving physical training programs into a more modern perspective as used by elite strength-power anaerobic athletes in sports today. Because the warfighter is an elite athlete, it is time that training approaches that are scientifically based are updated within the military to match the functional demands of modern warfare and are given greater credence and value at the command levels. A needs analysis, development of periodized training modules, and individualization of programs are needed to optimize the strength of the modern warfighter. We now have the knowledge, professional coaches and nonprofit organization certifications with continuing education units, and modern training technology to allow this to happen. Ultimately, it only takes command decisions and implementation to make this possible.

Modeling of Sylgard Adhesive Strength

Energy Technology Data Exchange (ETDEWEB)

Stevens, Ralph Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-02-03

Sylgard is the name of a silicone elastomeric potting material manufactured by Dow Corning Corporation.1 Although the manufacturer cites its low adhesive strength as a feature of this product, thin layers of Sylgard do in fact have a non-negligible strength, which has been measured in recent tensile and shear debonding tests. The adhesive strength of thin layers of Sylgard potting material can be important in applications in which components having signi cantly di erent thermal expansion properties are potted together, and the potted assembly is subjected to temperature changes. The tensile and shear tractions developed on the potted surfaces of the components can cause signi cant internal stresses, particularly for components made of low-strength materials with a high area-to-volume ratio. This report is organized as follows: recent Sylgard debonding tests are rst brie y summarized, with particular attention to the adhesion between Sylgard and PBX 9501, and also between Sylgard and aluminum. Next, the type of numerical model that will be used to simulate the debonding behavior exhibited in these tests is described. Then the calibration of the debonding model will be illustrated. Finally, the method by which the model parameters are adjusted (scaled) to be applicable to other, non- tested bond thicknesses is summarized, and all parameters of the model (scaled and unscaled) are presented so that other investigators can reproduce all of the simulations described in this report as well as simulations of the application of interest.

Factors influencing the thermally-induced strength degradation of B/Al composites

Science.gov (United States)

Dicarlo, J. A.

1983-01-01

Literature data related to the thermally-induced strength degradation of B/Al composites were examined in the light of fracture theories based on reaction-controlled fiber weakening. Under the assumption of a parabolic time-dependent growth for the interfacial reaction product, a Griffith-type fracture model was found to yield simple equations whose predictions were in good agreement with data for boron fiber average strength and for B/Al axial fracture strain. The only variables in these equations were the time and temperature of the thermal exposure and an empirical factor related to fiber surface smoothness prior to composite consolidation. Such variables as fiber diameter and aluminum alloy composition were found to have little influence. The basic and practical implications of the fracture model equations are discussed. Previously announced in STAR as N82-24297

Strength behaviour of sintered steel from the view of design-relevant material data

International Nuclear Information System (INIS)

Sonsino, C.M.; Esper, F.J.; Leuze, G.

1982-01-01

A reliable design of sintered components and an aimed material's selection requires the knowledge of designrelevant material data as Cyclic stress-strain-curves, crack propagation and fracture toughness properties as well as statistically evaluated S-N-curves, because conventional material data as tensile strength, monotonic yield strength, elongation, area reduction and impact strength can lead to a false estimation of the material's fatigue behaviour. For this reason the powder metallurgical industry began to determine design-relevant material data on the example of the porous Fe-Cu-C- and Fe-Cu-Ni-alloys. The fatigue tests with notched specimen and different modes of loading show that porous sintered parts having mechanical notches are less sensitive to external notches than wrought steel, because crack-propagation is delayed by pores. The possibility to manufacture cyclic hardening alloys, their relative notch-insensitivity and with wrought steel comparable scatter of fatigue properties show the importance of sintered alloys as alternative materials. (orig.) [de

Success in the Classroom and in Life: Focusing on Strengths of the Head "and" Strengths of the Heart

Science.gov (United States)

Pfeiffer, Steven I.

2017-01-01

"Strengths of the heart" is a new and potentially useful paradigm for understanding how the "whole" gifted child can thrive and flourish. Until recently, those who have written about and have researched the gifted have focused much of their work on "strengths of the head"--understanding, identifying, and promoting…

Strength anomaly in B2 FeAl single crystals

Energy Technology Data Exchange (ETDEWEB)

Yoshimi, K.; Hanada, S.; Yoo, M.H. [Oak Ridge National Lab., TN (United States); Matsumoto, N. [Tohoku Univ. (Japan). Graduate School

1994-12-31

Strength and deformation microstructure of B2 Fe-39 and 48%Al single crystals (composition given in atomic percent), which were fully annealed to remove frozen-in vacancies, have been investigated at temperatures between room temperature and 1073K. The hardness of as-homogenized Fe-48Al is higher than that of as-homogenized Fe-39Al while after additional annealing at 698K the hardness of Fe-48Al becomes lower than that of Fe-39Al. Fe-39Al single crystals slowly cooled after homogenizing at a high temperature were deformed in compression as a function of temperature and crystal orientation. A peak of yield strength appears around 0.5T{sub m} (T{sub m} = melting temperature). The orientation dependence of the critical resolved shear stress does not obey Schmid`s law even at room temperature and is quite different from that of b.c.c. metals and B2 intermetallics at low temperatures. At the peak temperature slip transition from <111>-type to <001>-type is found to occur macroscopically and microscopically, while it is observed in TEM that some of the [111] dislocations decompose into [101] and [010] on the (1096I) plane below the peak temperature. The physical sources for the positive temperature dependence of yield stress of B2 FeAl are discussed based on the obtained results.

Perturbation theory for arbitrary coupling strength?

Science.gov (United States)

Mahapatra, Bimal P.; Pradhan, Noubihary

2018-03-01

We present a new formulation of perturbation theory for quantum systems, designated here as: “mean field perturbation theory” (MFPT), which is free from power-series-expansion in any physical parameter, including the coupling strength. Its application is thereby extended to deal with interactions of arbitrary strength and to compute system-properties having non-analytic dependence on the coupling, thus overcoming the primary limitations of the “standard formulation of perturbation theory” (SFPT). MFPT is defined by developing perturbation about a chosen input Hamiltonian, which is exactly solvable but which acquires the nonlinearity and the analytic structure (in the coupling strength) of the original interaction through a self-consistent, feedback mechanism. We demonstrate Borel-summability of MFPT for the case of the quartic- and sextic-anharmonic oscillators and the quartic double-well oscillator (QDWO) by obtaining uniformly accurate results for the ground state of the above systems for arbitrary physical values of the coupling strength. The results obtained for the QDWO may be of particular significance since “renormalon”-free, unambiguous results are achieved for its spectrum in contrast to the well-known failure of SFPT in this case.

A review of the strength properties of dental ceramics.

Science.gov (United States)

Hondrum, S O

1992-06-01

New ceramic materials for restorative dentistry have been developed and introduced in recent years. This article reviews advantages and disadvantages of dental ceramics, concentrating on strength properties. Included are factors affecting the strength of dental ceramic materials and the most common mechanisms for increasing the strength of dental ceramics. The properties of presently available materials such as dispersion-strengthened ceramics, cast ceramics, and foil-reinforced materials are discussed. Current research efforts to improve the fracture resistance of ceramic restorative materials are reviewed. A description of methods to evaluate the strength of ceramics is included, as a caution concerning the interpretation of strength data reported in the literature.

An overview of strength training injuries: acute and chronic.

Science.gov (United States)

Lavallee, Mark E; Balam, Tucker

2010-01-01

This article introduces the history of strength training, explains the many different styles of strength training, and discusses common injuries specific to each style. Strength training is broken down into five disciplines: basic strength or resistance training, bodybuilding, power lifting, style-dependant strength sports (e.g., strongman competitions, Highland games, field events such as shot put, discus, hammer throw, and javelin), and Olympic-style weightlifting. Each style has its own principal injuries, both acute and chronic, related to the individual technique. Acute injuries should be further categorized as emergent or nonemergent. Specific age-related populations (i.e., the very young and the aging athlete) carry additional considerations.

A synchronous surround increases the motion strength gain of motion.

Science.gov (United States)

Linares, Daniel; Nishida, Shin'ya

2013-11-12

Coherent motion detection is greatly enhanced by the synchronous presentation of a static surround (Linares, Motoyoshi, & Nishida, 2012). To further understand this contextual enhancement, here we measured the sensitivity to discriminate motion strength for several pedestal strengths with and without a surround. We found that the surround improved discrimination of low and medium motion strengths, but did not improve or even impaired discrimination of high motion strengths. We used motion strength discriminability to estimate the perceptual response function assuming additive noise and found that the surround increased the motion strength gain, rather than the response gain. Given that eye and body movements continuously introduce transients in the retinal image, it is possible that this strength gain occurs in natural vision.

Evaluation of in-place concrete strength by core testing.

Science.gov (United States)

2016-11-01

The overall objective of the work contained in this report is to develop an ALDOT procedure to evaluate core strength results obtained under various conditions. Since there are many factors that influence the apparent strength of cores, strength corr...

Handgrip Strength: Indications of Paternal Inheritance in Three European Regions

DEFF Research Database (Denmark)

Cournil, Amandine; Jeune, Bernard; Skytthe, Axel

2010-01-01

BACKGROUND: Handgrip strength is an indicator of overall muscle strength. Poor handgrip strength is a risk factor for disability and mortality. We aimed to investigate the pattern of inheritance of handgrip strength in a sample of parent-offspring pairs from three different European regions...

Effects of Strength vs. Ballistic-Power Training on Throwing Performance.

Science.gov (United States)

Zaras, Nikolaos; Spengos, Konstantinos; Methenitis, Spyridon; Papadopoulos, Constantinos; Karampatsos, Giorgos; Georgiadis, Giorgos; Stasinaki, Aggeliki; Manta, Panagiota; Terzis, Gerasimos

2013-01-01

The purpose of the present study was to investigate the effects of 6 weeks strength vs. ballistic-power (Power) training on shot put throwing performance in novice throwers. Seventeen novice male shot-put throwers were divided into Strength (N = 9) and Power (n = 8) groups. The following measurements were performed before and after the training period: shot put throws, jumping performance (CMJ), Wingate anaerobic performance, 1RM strength, ballistic throws and evaluation of architectural and morphological characteristics of vastus lateralis. Throwing performance increased significantly but similarly after Strength and Power training (7.0-13.5% vs. 6.0-11.5%, respectively). Muscular strength in leg press increased more after Strength than after Power training (43% vs. 21%, respectively), while Power training induced an 8.5% increase in CMJ performance and 9.0 - 25.8% in ballistic throws. Peak power during the Wingate test increased similarly after Strength and Power training. Muscle thickness increased only after Strength training (10%, p ballistic power training in novice throwers, but with dissimilar muscular adaptations. Key pointsBallistic-power training with 30% of 1RM is equally effective in increasing shot put performance as strength training, in novice throwers, during a short training cycle of six weeks.In novice shot putters with relatively low initial muscle strength/mass, short-term strength training might be more important since it can increase both muscle strength and shot put performance.The ballistic type of power training resulted in a significant increase of the mass of type IIx muscle fibres and no change in their proportion. Thus, this type of training might be used effectively during the last weeks before competition, when the strength training load is usually reduced, in order to increase muscle power and shot put performance in novice shot putters.

Impact of Hydrodynamics on Oral Biofilm Strength

NARCIS (Netherlands)

Paramonova, E.; Kalmykowa, O. J.; van der Mei, H. C.; Busscher, H. J.; Sharma, P. K.

2009-01-01

Mechanical removal of oral biofilms is ubiquitously accepted as the best way to prevent caries and periodontal diseases. Removal effectiveness strongly depends on biofilm strength. To investigate the influence of hydrodynamics on oral biofilm strength, we grew single- and multi-species biofilms of

Making High-Tensile-Strength Amalgam Components

Science.gov (United States)

Grugel, Richard

2008-01-01

Structural components made of amalgams can be made to have tensile strengths much greater than previously known to be possible. Amalgams, perhaps best known for their use in dental fillings, have several useful attributes, including room-temperature fabrication, corrosion resistance, dimensional stability, and high compressive strength. However, the range of applications of amalgams has been limited by their very small tensile strengths. Now, it has been discovered that the tensile strength of an amalgam depends critically on the sizes and shapes of the particles from which it is made and, consequently, the tensile strength can be greatly increased through suitable choice of the particles. Heretofore, the powder particles used to make amalgams have been, variously, in the form of micron-sized spheroids or flakes. The tensile reinforcement contributed by the spheroids and flakes is minimal because fracture paths simply go around these particles. However, if spheroids or flakes are replaced by strands having greater lengths, then tensile reinforcement can be increased significantly. The feasibility of this concept was shown in an experiment in which electrical copper wires, serving as demonstration substitutes for copper powder particles, were triturated with gallium by use of a mortar and pestle and the resulting amalgam was compressed into a mold. The tensile strength of the amalgam specimen was then measured and found to be greater than 10(exp 4) psi (greater than about 69 MPa). Much remains to be done to optimize the properties of amalgams for various applications through suitable choice of starting constituents and modification of the trituration and molding processes. The choice of wire size and composition are expected to be especially important. Perusal of phase diagrams of metal mixtures could give insight that would enable choices of solid and liquid metal constituents. Finally, whereas heretofore, only binary alloys have been considered for amalgams

EFFECTS OF STRENGTH VS. BALLISTIC-POWER TRAINING ON THROWING PERFORMANCE

Directory of Open Access Journals (Sweden)

Nikolaos Zaras

2013-03-01

Full Text Available The purpose of the present study was to investigate the effects of 6 weeks strength vs. ballistic-power (Power training on shot put throwing performance in novice throwers. Seventeen novice male shot-put throwers were divided into Strength (N = 9 and Power (n = 8 groups. The following measurements were performed before and after the training period: shot put throws, jumping performance (CMJ, Wingate anaerobic performance, 1RM strength, ballistic throws and evaluation of architectural and morphological characteristics of vastus lateralis. Throwing performance increased significantly but similarly after Strength and Power training (7.0-13.5% vs. 6.0-11.5%, respectively. Muscular strength in leg press increased more after Strength than after Power training (43% vs. 21%, respectively, while Power training induced an 8.5% increase in CMJ performance and 9.0 - 25.8% in ballistic throws. Peak power during the Wingate test increased similarly after Strength and Power training. Muscle thickness increased only after Strength training (10%, p < 0.05. Muscle fibre Cross Sectional Area (fCSA increased in all fibre types after Strength training by 19-26% (p < 0.05, while only type IIx fibres hypertrophied significantly after Power training. Type IIx fibres (% decreased after Strength but not after Power training. These results suggest that shot put throwing performance can be increased similarly after six weeks of either strength or ballistic power training in novice throwers, but with dissimilar muscular adaptations

STRENGTH AND CONDITIONING PRACTICES OF IRAN Wrestling League STRENGTH AND CONDITIONING COACHES

Directory of Open Access Journals (Sweden)

Far Saeed Jamshidi

2014-08-01

Full Text Available Purpose : The purpose of this study describes the results of a survey of the practices of Iranian Wrestling League strength and conditioning (IWL S&C coaches. Material: The response rate was 88.5% (100 of 113. The contents survey examines include: (a background information, (b physical testing, (c flexibility development, (d speed development, (e plyometrics, (f strength/power development, (g unique aspects, and (h comments from coaches providing additional information. Results: Results indicate, in part, that coaches assess an average of 7.3 parameters of fitness, with tests speed being the most common. All coaches used a variety of flexibility development strategies. Results reveal that all of IWL S&C coaches follow a periodization model. Speed as the first priority (100% and muscular endurance, power and strength as second priority (97% of importance in evaluating their athletes. Sixty-six percent coaches (66% indicated that their athletes used Olympic-style lifts. All coaches employed plyometric exercises with their athletes. Ninety-two percent (92% of the coaches reported that used plyometric trainings for increasing the speed of their wrestlers and 82% of the coaches used plyometric jump in place exercises as regular practice in their trainings. Conclusions: The squat and its variations, as well as the Olympic-style lifts and their variations, were the most frequently used exercises. The survey serves as a review and a source of applied information and new ideas.

G×E Interaction Influences Trajectories of Hand Grip Strength

DEFF Research Database (Denmark)

Petersen, Inge; Pedersen, Nancy L; Rantanen, Taina

2016-01-01

Age-related decline in grip strength predicts later life disability, frailty, lower well-being and cognitive change. While grip strength is heritable, genetic influence on change in grip strength has been relatively ignored, with non-shared environmental influence identified as the primary contri...

Effect of Ionic Strength on Settling of Activated Sludge

OpenAIRE

M Ahmadi Moghadam, M Soheili, MM Esfahani

2005-01-01

Structural properties of activated sludge flocs were found to be sensitive to small changes in ionic strength. This study investigates the effect of ionic strength on settling of activated sludge. Samples were taken from activated sludge process of Ghazvin Sasan soft drink wastewater treatment plant, then treated with different ionic strengths of KCl and CaCl2 solution, after that the turbidity of supernatant was measured. The results indicated that low ionic strength resulted in a steeper sl...

The strengths perspective in client’s social case management

OpenAIRE

Valpētere, Laima

2010-01-01

The subject diploma paper is „The strengths perspective in client’s social case management.” The aim of the diploma paper is to research the strengths perspective in client’s social case management. Diploma paper consists of five chapters. In the first chapter the case management was theoretically researched. In the second chapter was done description of the strengths perspective in the social work. In the third chapter by describing principles and strategies of strengths perspective, cli...

Variations in the microstructure and properties of Mn-Ti multiple-phase steel with high strength under different tempering temperatures

Science.gov (United States)

Li, Dazhao; Li, Xiaonan; Cui, Tianxie; Li, Jianmin; Wang, Yutian; Fu, Peimao

2015-03-01

There are few relevant researches on coils by tempering, and the variations of microstructure and properties of steel coil during the tempering process also remain unclear. By using thermo-mechanical control process(TMCP) technology, Mn-Ti typical HSLA steel coils with yield strength of 920 MPa are produced on the 2250 hot rolling production line. Then, the samples are taken from the coils and tempered at the temperatures of 220 °C, 350 °C, and 620 °C respectively. After tempering the strength, ductility and toughness of samples are tested, and meanwhile microstructures are investigated. Precipitates initially emerge inside the ferrite laths and the density of the dislocation drops. Then, the lath-shaped ferrites begin to gather, and the retained austenite films start to decompose. Finally, the retained austenite films are completely decomposed into coarse and short rod-shape precipitates composed of C and Ti compounds. The yield strength increases with increasing tempering temperature due to the pinning effect of the precipitates, and the dislocation density decreases. The yield strength is highest when the steel is tempered at 220 °C because of pinning of the precipitates to dislocations. The total elongation increases in all samples because of the development of ferrites during tempering. The tensile strength and impact absorbed energy decline because the effect of impeding crack propagation weakens as the retained austenite films completely decompose and the precipitates coarsen. This paper clarifies the influence of different tempering temperatures on phase transformation characteristics and process of Mn-Ti typical multiphase steels, as well as its resulting performance variation rules.

The Effect of Heat Treatment on the Pull-off Strength of Optionally Varnished Surfaces of Five Wood Materials

Directory of Open Access Journals (Sweden)

Musa Atar

2015-09-01

Full Text Available This study investigated the effects of heat treatment, following optional treatment with synthetic, water-based, and alkyd varnishes, on the pull-off strength of wooden materials sampled from oriental beech (Fagus orientalis L., oak (Quercus petraea Liebl., black poplar (Populus nigra L., pine (Pinus sylvestris L., and fir (Abies bornmulleriana M.. The test samples were subjected to heat treatment at temperatures of 165 °C and 175 °C for periods of 2 and 4 h with a total of 4 variations. With respect to the wood type, the samples of beech wood yielded the highest results for pull-off strength, while fir wood yielded the lowest. With respect to the varnish types, the highest pull-off strength was found in the samples of synthetic varnished beech (5,452 with a 37.2% improvement at 175 °C heat treatment for 4 h, while the lowest results were obtained in the samples of fir (0.991 with a 48.5% decrease at 175 °C heat treatment for 4 h. In conclusion, heat treatment significantly decreased the pull-off strength of the woods.

Strength Development: Using Functional Isometrics in an Isotonic Strength Training Program.

Science.gov (United States)

Jackson, Allen; And Others

1985-01-01

A study was made to determine if a combination of functional isometrics and standard isotonic training would be superior to a standard isotonic program in an instructional setting. The results provide support for functional isometrics as an enhancement where achievement of maximum strength is the goal. (Author/MT)

The Effect of Tempering on Strength Properties and Seed Coat ...

African Journals Online (AJOL)

The effect of tempering on seed coat adhesion strength and mechanical strength of sorghum and millet grain kernels was investigated at different tempering durations. Tempering reduced the kernel breaking strength and had significant effect on seed coat adhesion strength. Tempering the grain for 60 minutes at ambient ...

Strength conditions for the elastic structures with a stress error

Science.gov (United States)

Matveev, A. D.

2017-10-01

As is known, the constraints (strength conditions) for the safety factor of elastic structures and design details of a particular class, e.g. aviation structures are established, i.e. the safety factor values of such structures should be within the given range. It should be noted that the constraints are set for the safety factors corresponding to analytical (exact) solutions of elasticity problems represented for the structures. Developing the analytical solutions for most structures, especially irregular shape ones, is associated with great difficulties. Approximate approaches to solve the elasticity problems, e.g. the technical theories of deformation of homogeneous and composite plates, beams and shells, are widely used for a great number of structures. Technical theories based on the hypotheses give rise to approximate (technical) solutions with an irreducible error, with the exact value being difficult to be determined. In static calculations of the structural strength with a specified small range for the safety factors application of technical (by the Theory of Strength of Materials) solutions is difficult. However, there are some numerical methods for developing the approximate solutions of elasticity problems with arbitrarily small errors. In present paper, the adjusted reference (specified) strength conditions for the structural safety factor corresponding to approximate solution of the elasticity problem have been proposed. The stress error estimation is taken into account using the proposed strength conditions. It has been shown that, to fulfill the specified strength conditions for the safety factor of the given structure corresponding to an exact solution, the adjusted strength conditions for the structural safety factor corresponding to an approximate solution are required. The stress error estimation which is the basis for developing the adjusted strength conditions has been determined for the specified strength conditions. The adjusted strength

Handgrip strength does not represent an appropriate measure to evaluate changes in muscle strength during an exercise intervention program in frail elderly people

NARCIS (Netherlands)

Tieland, C.A.B.; Verdijk, L.; Groot, de C.P.G.M.; Loon, van L.J.C.

2015-01-01

Although handgrip strength is considered a strong predictor of negative health outcomes, it is unclear whether handgrip strength represents a useful measure to evaluate changes in muscle strength following resistance-type exercise training in elderly people. We assessed whether measuring handgrip

Revealing the Maximum Strength in Nanotwinned Copper

DEFF Research Database (Denmark)

Lu, L.; Chen, X.; Huang, Xiaoxu

2009-01-01

boundary–related processes. We investigated the maximum strength of nanotwinned copper samples with different twin thicknesses. We found that the strength increases with decreasing twin thickness, reaching a maximum at 15 nanometers, followed by a softening at smaller values that is accompanied by enhanced...

The strength of polyaxial locking interfaces of distal radius plates.

Science.gov (United States)

Hoffmeier, Konrad L; Hofmann, Gunther O; Mückley, Thomas

2009-10-01

Currently available polyaxial locking plates represent the consequent enhancement of fixed-angle, first-generation locking plates. In contrast to fixed-angle locking plates which are sufficiently investigated, the strength of the new polyaxial locking options has not yet been evaluated biomechanically. This study investigates the mechanical strength of single polyaxial interfaces of different volar radius plates. Single screw-plate interfaces of the implants Palmar 2.7 (Königsee Implantate und Instrumente zur Osteosynthese GmbH, Allendorf, Germany), VariAx (Stryker Leibinger GmbH & Co. KG, Freiburg, Germany) und Viper (Integra LifeSciences Corporation, Plainsboro, NJ, USA) were tested by cantilever bending. The strength of 0 degrees, 10 degrees and 20 degrees screw locking angle was obtained during static and dynamic loading. The Palmar 2.7 interfaces showed greater ultimate strength and fatigue strength than the interfaces of the other implants. The strength of the VariAx interfaces was about 60% of Palmar 2.7 in both, static and dynamic loading. No dynamic testing was applied to the Viper plate because of its low ultimate strength. By static loading, an increase in screw locking angle caused a reduction of strength for the Palmar 2.7 and Viper locking interfaces. No influence was observed for the VariAx locking interfaces. During dynamic loading; angulation had no influence on the locking strength of Palmar 2.7. However, reduction of locking strength with increasing screw angulation was observed for VariAx. The strength of the polyaxial locking interfaces differs remarkably between the examined implants. Depending on the implant an increase of the screw locking angle causes a reduction of ultimate or fatigue strength, but not in all cases a significant impact was observed.

The Effects of Extravehicular Activity (EVA) Glove Pressure on Hand Strength

Science.gov (United States)

Mesloh, Miranda; England, Scott; Benson, Elizabeth; Thompson, Shelby; Rajulu, Sudhakar

2010-01-01

The purpose of this study was to characterize hand strength, while wearing a Phase VI Extravehicular Activity (EVA) glove in an Extravehicular Mobility Unit (EMU) suit. Three types of data were collected: hand grip, lateral pinch, and pulp-2 pinch, wider three different conditions: bare-handed, gloved with no Thermal Micrometeoroid Garment (TMG), and glove with TMG. In addition, during the gloved conditions, subjects were tested when unpressurized and pressurized (43 psi). As a percentage of bare-hand strength, the TMG condition showed reduction in grip strength to 55% unpressurized and 46% pressurized. Without the TMG, grip strength increased to 66% unpressurized and 58% pressurized of bare-hand strength. For lateral pinch strength, the reduction in strength was the same for both pressure conditions and with and without the TMG, about 8.5% of bare-hand Pulp-2 pinch strength with no TMG showed an increase to 122% unpressurized and 115% pressurized of bare-hand strength. While wearing the TMG, pulp-2 pinch strength was 115% of bare-hand strength for both pressure conditions.

Wireless Concrete Strength Monitoring of Wind Turbine Foundations.

Science.gov (United States)

Perry, Marcus; Fusiek, Grzegorz; Niewczas, Pawel; Rubert, Tim; McAlorum, Jack

2017-12-16

Wind turbine foundations are typically cast in place, leaving the concrete to mature under environmental conditions that vary in time and space. As a result, there is uncertainty around the concrete's initial performance, and this can encourage both costly over-design and inaccurate prognoses of structural health. Here, we demonstrate the field application of a dense, wireless thermocouple network to monitor the strength development of an onshore, reinforced-concrete wind turbine foundation. Up-to-date methods in fly ash concrete strength and maturity modelling are used to estimate the distribution and evolution of foundation strength over 29 days of curing. Strength estimates are verified by core samples, extracted from the foundation base. In addition, an artificial neural network, trained using temperature data, is exploited to demonstrate that distributed concrete strengths can be estimated for foundations using only sparse thermocouple data. Our techniques provide a practical alternative to computational models, and could assist site operators in making more informed decisions about foundation design, construction, operation and maintenance.

Effect of 8 weeks of free-weight and machine-based strength training on strength and power performance

Directory of Open Access Journals (Sweden)

Wirth Klaus

2016-12-01

Full Text Available The aim of this study was to evaluate the effectiveness of free-weight and machine-based exercises to increase different strength and speed-strength variables. One hundred twenty male participants (age: 23.8 ± 2.5 years; body height: 181.0 ± 6.8 cm; body mass: 80.2 ± 8.9 kg joined the study. The 2 experimental groups completed an 8 week periodized strength training program that included 2 training sessions per week. The exercises that were used in the strength training programs were the parallel barbell squat and the leg press. Before and after the training period, the 1-repetition-maximum in the barbell squat and the leg press, the squat jump, the countermovement jump and unilateral isometric force (maximal isometric force and the rate of force development were evaluated. To compare each group pre vs. post-intervention, analysis of variance with repeated measures and Scheffé post-hoc tests were used. The leg press group increased their 1-repetition-maximum significantly (p < 0.001, while in the squat group such variables as 1-repetition-maximum, the squat jump and the countermovement jump increased significantly (p < 0.001. The maximal isometric force showed no statistically significant result for the repeated measures factor, while the rate of force development of the squat group even showed a statistically significant decrease. Differences between the 2 experimental groups were detected for the squat jump and the countermovement jump. In comparison with the leg press, the squat might be a better strength training exercise for the development of jump performance.

On irregularity strength of disjoint union of friendship graphs

Directory of Open Access Journals (Sweden)

Ali Ahmad

2013-11-01

Full Text Available We investigate the vertex total and edge total modication of the well-known irregularity strength of graphs. We have determined the exact values of the total vertex irregularity strength and the total edge irregularity strength of a disjoint union of friendship graphs.

Regulation of assimilate import into sink organs: Update on molecular drivers of sink strength

Directory of Open Access Journals (Sweden)

Saadia eBihmidine

2013-06-01

Full Text Available Recent developments have altered our view of molecular mechanisms that determine sink strength, defined here as the capacity of non-photosynthetic structures to compete for import of photoassimilates. We review new findings from diverse systems, including stems, seeds, flowers, and fruits. An important advance has been the identification of new transporters and facilitators with major roles in the accumulation and equilibration of sugars at a cellular level. Exactly where each exerts its effect varies among systems. Sugarcane and sweet sorghum stems, for example, both accumulate high levels of sucrose, but may do so via different paths. The distinction is central to strategies for targeted manipulation of sink strength using transporter genes, and shows the importance of system-specific analyses. Another major advance has been the identification of deep hypoxia as a feature of normal grain development. This means that molecular drivers of sink strength in endosperm operate in very low oxygen levels, and under metabolic conditions quite different than previously assumed. Successful enhancement of sink strength has nonetheless been achieved in grains by up-regulating genes for starch biosynthesis. Additionally, our understanding of sink strength is enhanced by awareness of the dual roles played by invertases (INV, not only in sucrose metabolism, but also in production of the hexose sugar signals that regulate cell-cycle and cell-division programs. These contributions of INV to cell expansion and division prove to be vital for establishment of young sinks ranging from flowers to fruit. Since INV genes are themselves sugar-responsive feast genes, they can mediate a feed-forward enhancement of sink strength when assimilates are abundant. Greater overall productivity and yield have thus been attained in key instances, indicating that even broader enhancements may be achievable as we discover the detailed molecular mechanisms that drive sink strength

Strength training and body composition in middle-age women.

Science.gov (United States)

Burrup, Rachelle; Tucker, Larry A; LE Cheminant, James D; Bailey, Bruce W

2018-01-01

Strength training is a sound method to improve body composition. However, the effect of age, diet, menopause, and physical activity on the relationship between strength training and body composition in women remains unknown. The purpose of this study was to examine the intricacies of the relationship between strength training and body composition in 257 middle-age women and to quantify the effect of these factors on the association. The study was cross-sectional. Five variables were used to index strength training participation. Body composition was assessed by dual-energy X-ray absorptiometry. Diet was assessed by 7-day weighed food records, and physical activity was measured objectively using accelerometers. There were 109 strength trainers in the sample. For each day per week of strength training, body fat was 1.3 percentage points lower (F=14.8, Pdevote to strength training, the lower their body fat and the higher their fat-free mass tend to be. A significant portion of the differences in body composition seems to result from lifters participating in more physical activity than non-lifters. Menopause status also contributes significantly to the relationship.

Ultrasound transmission measurements for tensile strength evaluation of tablets.

Science.gov (United States)

Simonaho, Simo-Pekka; Takala, T Aleksi; Kuosmanen, Marko; Ketolainen, Jarkko

2011-05-16

Ultrasound transmission measurements were performed to evaluate the tensile strength of tablets. Tablets consisting of one ingredient were compressed from dibasic calcium phosphate dehydrate, two grades of microcrystalline cellulose and two grades of lactose monohydrate powders. From each powder, tablets with five different tensile strengths were directly compressed. Ultrasound transmission measurements were conducted on every tablet at frequencies of 2.25 MHz, 5 MHz and 10 MHz and the speed of sound was calculated from the acquired waveforms. The tensile strength of the tablets was determined using a diametrical mechanical testing machine and compared to the calculated speed of sound values. It was found that the speed of sound increased with the tensile strength for the tested excipients. There was a good correlation between the speed of sound and tensile strength. Moreover, based on the statistical tests, the groups with different tensile strengths can be differentiated from each other by measuring the speed of sound. Thus, the ultrasound transmission measurement technique is a potentially useful method for non-destructive and fast evaluation of the tensile strength of tablets. Copyright © 2011 Elsevier B.V. All rights reserved.

Biot's coefficient as an indicator of strength and porosity reduction: Calcareous sediments from Kerguelen Plateau

DEFF Research Database (Denmark)

Alam, Mohammad Monzurul; Borre, Mai Kirstine; Fabricius, Ida Lykke

2010-01-01

β to fall, even when porosity remains constant. Biot's coefficient correlates with strength-indicating properties: compressional and shear modulus, oedometer modulus, yield strength, strain from direct loading and creep strain. Our data indicate that β may be used for predicting the diagenetic...... Biot's coefficient, β. In calcareous ooze, β is one. Mechanical compaction reduces porosity, but only leads to a minor decrease in β. Recrystallization renders particles smoother, but does not lead to reduction in β unless it gives rise to pore stiffening cementation. Pore stiffening cementation causes...

Modeling the Effect of Nail Corrosion on the Lateral Strength of Joints

Science.gov (United States)

Samuel L. Zelinka; Douglas R. Rammer

2012-01-01

This article describes a theoretical method of linking fastener corrosion in wood connections to potential reduction in lateral shear strength. It builds upon published quantitative data of corrosion rates of metals in contact with treated wood for several different wood preservatives. These corrosion rates are then combined with yield theory equations to calculate a...

Compressive strength improvement for recycled concrete aggregate

Directory of Open Access Journals (Sweden)

Mohammed Dhiyaa

2018-01-01

Full Text Available Increasing amount of construction waste and, concrete remnants, in particular pose a serious problem. Concrete waste exist in large amounts, do not decay and need long time for disintegration. Therefore, in this work old demolished concrete is crashed and recycled to produce recycled concrete aggregate which can be reused in new concrete production. The effect of using recycled aggregate on concrete compressive strength has been experimentally investigated; silica fume admixture also is used to improve recycled concrete aggregate compressive strength. The main parameters in this study are recycled aggregate and silica fume admixture. The percent of recycled aggregate ranged from (0-100 %. While the silica fume ranged from (0-10 %. The experimental results show that the average concrete compressive strength decreases from 30.85 MPa to 17.58 MPa when the recycled aggregate percentage increased from 0% to 100%. While, when silica fume is used the concrete compressive strength increase again to 29.2 MPa for samples with 100% of recycled aggregate.

Roles of pinning strength and density in vortex melting

International Nuclear Information System (INIS)

Obaidat, I M; Khawaja, U Al; Benkraouda, M

2008-01-01

We have investigated the role of pinning strength and density on the equilibrium vortex-lattice to vortex-liquid phase transition under several applied magnetic fields. This study was conducted using a series of molecular dynamic simulations on several samples with different strengths and densities of pinning sites which are arranged in periodic square arrays. We have found a single solid-liquid vortex transition when the vortex filling factor n>1. We have found that, for fixed pinning densities and strengths, the melting temperature, T m , decreases almost linearly with increasing magnetic field. Our results provide direct numerical evidence for the significant role of both the strength and density of pinning centers on the position of the melting line. We have found that the vortex-lattice to vortex-liquid melting line shifts up as the pinning strength or the pinning density was increased. The effect on the melting line was found to be more pronounced at small values of strength and density of pinning sites

Pathogens as Predictors of Honey Bee Colony Strength in England and Wales.

Science.gov (United States)

Budge, Giles E; Pietravalle, Stéphane; Brown, Mike; Laurenson, Lynn; Jones, Ben; Tomkies, Victoria; Delaplane, Keith S

2015-01-01

Inspectors with the UK National Bee Unit were asked for 2007-2008 to target problem apiaries in England and Wales for pathogen screening and colony strength measures. Healthy colonies were included in the sampling to provide a continuum of health conditions. A total of 406 adult bee samples was screened and yielded 7 viral, 1 bacterial, and 2 microsporidial pathogens and 1 ectoparasite (Acarapis woodi). In addition, 108 samples of brood were screened and yielded 4 honey bee viruses. Virus prevalence varied from common (deformed wing virus, black queen cell virus) to complete absence (Israeli acute paralysis virus). When colonies were forced into one of two classes, strong or weak, the weak colonies contained more pathogens in adult bees. Among observed pathogens, only deformed wing virus was able to predict colony strength. The effect was negative such that colonies testing positive for deformed wing virus were likely to have fewer combs of bees or brood. This study constitutes the first record for Nosema ceranae in Great Britain. These results contribute to the growing body of evidence linking pathogens to poor honey bee health.

Strength Properties of Aalborg Clay

DEFF Research Database (Denmark)

Iversen, Kirsten Malte; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust

glacial time are characterised by the absence of this mussel. These deposits are named Aalborg Clay and Aalborg Sand. In the city of Aalborg, a fill layer superposes Aalborg Clay. This layer is at some places found to be 6m thick. This fill layer does not provide sufficient bearing capacity, which has...... resulted in many damaged buildings in Aalborg. To provide sufficient bearing capacity it is therefore necessary either to remove the fill or to construct the building on piles. Both methods imply that the strength of Aalborg Clay is important for the construction. This paper evaluates the strength...

High-strength mineralized collagen artificial bone

Science.gov (United States)

Qiu, Zhi-Ye; Tao, Chun-Sheng; Cui, Helen; Wang, Chang-Ming; Cui, Fu-Zhai

2014-03-01

Mineralized collagen (MC) is a biomimetic material that mimics natural bone matrix in terms of both chemical composition and microstructure. The biomimetic MC possesses good biocompatibility and osteogenic activity, and is capable of guiding bone regeneration as being used for bone defect repair. However, mechanical strength of existing MC artificial bone is too low to provide effective support at human load-bearing sites, so it can only be used for the repair at non-load-bearing sites, such as bone defect filling, bone graft augmentation, and so on. In the present study, a high strength MC artificial bone material was developed by using collagen as the template for the biomimetic mineralization of the calcium phosphate, and then followed by a cold compression molding process with a certain pressure. The appearance and density of the dense MC were similar to those of natural cortical bone, and the phase composition was in conformity with that of animal's cortical bone demonstrated by XRD. Mechanical properties were tested and results showed that the compressive strength was comparable to human cortical bone, while the compressive modulus was as low as human cancellous bone. Such high strength was able to provide effective mechanical support for bone defect repair at human load-bearing sites, and the low compressive modulus can help avoid stress shielding in the application of bone regeneration. Both in vitro cell experiments and in vivo implantation assay demonstrated good biocompatibility of the material, and in vivo stability evaluation indicated that this high-strength MC artificial bone could provide long-term effective mechanical support at human load-bearing sites.

Strengths as the Foundation for Intervention with Black Youth

Science.gov (United States)

Lambert, Michael Canute; Rowan, George T.; Longhurst, Jim; Kim, Soyoun

2006-01-01

The inherent strengths of Black youth are sometimes overlooked by assessment and intervention following perspectives of the dominant culture. This article describes the unique ways in which strengths and difficulties are defined in Black culture. This research is informing more appropriate strategies for building on the strengths of this…

47 CFR 27.55 - Power strength limits.

Science.gov (United States)

2010-10-01

... following bands, the predicted or measured median field strength at any location on the geographical border... predicted or measured median field strength at any location on the geographical border of a licensee's... antenna mounting structure. (c) Power flux density limit for stations operating in the 746-757 MHz, 758...

Asymmetry of Muscle Strength in Elite Athletes

Science.gov (United States)

Drid, Patrik; Drapsin, Miodrag; Trivic, Tatjana; Lukac, Damir; Obadov, Slavko; Milosevic, Zoran

2009-01-01

"Study aim": To determine muscle strength variables in elite judoists and wrestlers since thigh muscle strength and bilaterally balanced flexor-to-extensor ratio minimise injury risk and are desirable for achieving sport successes. "Material and methods": Judoists, wrestlers and untrained subjects, 10 each, were subjected to isokinetic strength…

Static and Dynamic Handgrip Strength Endurance: Test-Retest Reproducibility.

Science.gov (United States)

Gerodimos, Vassilis; Karatrantou, Konstantina; Psychou, Dimitra; Vasilopoulou, Theodora; Zafeiridis, Andreas

2017-03-01

This study investigated the reliability of static and dynamic handgrip strength endurance using different protocols and indicators for the assessment of strength endurance. Forty young, healthy men and women (age, 18-22 years) performed 2 handgrip strength endurance protocols: a static protocol (sustained submaximal contraction at 50% of maximal voluntary contraction) and a dynamic one (8, 10, and 12 maximal repetitions). The participants executed each protocol twice to assess the test-retest reproducibility. Total work and total time were used as indicators of strength endurance in the static protocol; the strength recorded at each maximal repetition, the percentage change, and fatigue index were used as indicators of strength endurance in the dynamic protocol. The static protocol showed high reliability irrespective of sex and hand for total time and work. The 12-repetition dynamic protocol exhibited moderate-high reliability for repeated maximal repetitions and percentage change; the 8- and 10-repetition protocols demonstrated lower reliability irrespective of sex and hand. The fatigue index was not a reliable indicator for the assessment of dynamic handgrip endurance. Static handgrip endurance can be measured reliably using the total time and total work as indicators of strength endurance. For the evaluation of dynamic handgrip endurance, the 12-repetition protocol is recommended, using the repeated maximal repetitions and percentage change as indicators of strength endurance. Practitioners should consider the static (50% maximal voluntary contraction) and dynamic (12 repeated maximal repetitions) protocols as reliable for the assessment of handgrip strength endurance. The evaluation of static endurance in conjunction with dynamic endurance would provide more complete information about hand function. Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Hip strength and range of motion

DEFF Research Database (Denmark)

Mosler, Andrea B.; Crossley, Kay M.; Thorborg, Kristian

2017-01-01

Objectives To determine the normal profiles for hip strength and range of motion (ROM) in a professional football league in Qatar, and examine the effect of leg dominance, age, past history of injury, and ethnicity on these profiles. Design Cross-sectional cohort study. Methods Participants...... values are documented for hip strength and range of motion that can be used as reference profiles in the clinical assessment, screening, and management of professional football players. Leg dominance, recent past injury history and ethnicity do not need to be accounted for when using these profiles...... included 394 asymptomatic, male professional football players, aged 18–40 years. Strength was measured using a hand held dynamometer with an eccentric test in side-lying for hip adduction and abduction, and the squeeze test in supine with 45° hip flexion. Range of motion measures included: hip internal...

Measurements of (p,γ) resonance strengths in the s-d shell

NARCIS (Netherlands)

Engelbertink, G.A.P.; Endt, P.M.

1966-01-01

Resonace strengths of selected resonances in the Ep=0.3−2.1 MeV region in the (p, γ) reactions on 23Na, 24–24Mg, 27Al, 28–30Si, 31P, 32, 34S, 35, 37Cl, 39, 41K and 40Ca are compared through relative yield measurements, using targets of many different chemical compounds, each containing at least two

Strength development of high-strength ductile concrete incorporating Metakaolin and PVA fibers.

Science.gov (United States)

Nuruddin, Muhammad Fadhil; Khan, Sadaqat Ullah; Shafiq, Nasir; Ayub, Tehmina

2014-01-01

The mechanical properties of high-strength ductile concrete (HSDC) have been investigated using Metakaolin (MK) as the cement replacing material and PVA fibers. Total twenty-seven (27) mixes of concrete have been examined with varying content of MK and PVA fibers. It has been found that the coarser type PVA fibers provide strengths competitive to control or higher than control. Concrete with coarser type PVA fibers has also refined microstructure, but the microstructure has been undergone with the increase in aspect ratio of fibers. The microstructure of concrete with MK has also more refined and packing of material is much better with MK. PVA fibers not only give higher stiffness but also showed the deflection hardening response. Toughness Index of HSDC reflects the improvement in flexural toughness over the plain concrete and the maximum toughness indices have been observed with 10% MK and 2% volume fraction of PVA fibers.

Strength and structure of nanocrystalline titanium

International Nuclear Information System (INIS)

Noskova, N.I.; Pereturina, I.A.; Elkina, O.A.; Stolyarov, V.V.

2004-01-01

Investigation results on strength and plasticity of nanocrystalline titanium VT-1 are presented. Specific features of plastic deformation on tension of this material specimens in an electron microscope column are studied in situ. It is shown that nanocrystalline titanium strength and plasticity at room temperature are dependent on the structure and nanograin size. It is revealed that deformation processes in nanocrystalline titanium are characterized by activation of deformation rotational modes and microtwinning [ru

(p,t) strengths in the Ga isotopes

International Nuclear Information System (INIS)

Rotbard, G.; Vergnes, M.; Berrier-Ronsin, G.; Vernotte, J.; Tamisier, R.

1984-01-01

The (p,t) reaction on the two stable Ga isotopes has been performed at 25 MeV, with 11 keV energy resolution. Levels up to 3.5 MeV in 67 Ga, 4.3 MeV in 69 Ga were measured. Differences observed in comparing the distribution of the L=2 (p,t) strength with the distribution of the B(E2) strength may be explained by a mixed character of the 7/2 2 - level wave function. The distribution of the L=0 strength indicates that the striking change in ground-state structure shown between N=40 and 42 already begins, although weakly, between N=38 and 40

Electric and Magnetic Dipole Strength at Low Energy

Science.gov (United States)

Sieja, K.

2017-08-01

A low-energy enhancement of radiative strength functions was deduced from recent experiments in several mass regions of nuclei, which is believed to impact considerably the calculated neutron capture rates. In this Letter we investigate the behavior of the low-energy γ -ray strength of the Sc 44 isotope, for the first time taking into account both electric and magnetic dipole contributions obtained coherently in the same theoretical approach. The calculations are performed using the large-scale shell-model framework in a full 1 ℏω s d -p f -g d s model space. Our results corroborate previous theoretical findings for the low-energy enhancement of the M 1 strength but show quite different behavior for the E 1 strength.

Effect of Boron on the Strength and Toughness of Direct-Quenched Low-Carbon Niobium Bearing Ultra-High-Strength Martensitic Steel

Science.gov (United States)

Hannula, Jaakko; Kömi, Jukka; Porter, David A.; Somani, Mahesh C.; Kaijalainen, Antti; Suikkanen, Pasi; Yang, Jer-Ren; Tsai, Shao-Pu

2017-11-01

The effect of boron on the microstructures and mechanical properties of laboratory-control-rolled and direct-quenched 6-mm-thick steels containing 0.08 wt pct C and 0.02 wt pct Nb were studied. The boron contents were 24 ppm and a residual amount of 4 ppm. Two different finish rolling temperatures (FRTs) of 1093 K and 1193 K (820 °C and 920 °C) were used in the hot rolling trials to obtain different levels of pancaked austenite prior to DQ. Continuous cooling transformation (CCT) diagrams were constructed to reveal the effect of boron on the transformation behavior of these steels. Microstructural characterization was carried out using various microscopy techniques, such as light optical microscopy (LOM) and scanning electron microscopy-electron backscatter diffraction (SEM-EBSD). The resultant microstructures after hot rolling were mixtures of autotempered martensite and lower bainite (LB), having yield strengths in the range 918 to 1067 MPa with total elongations to fracture higher than 10 pct. The lower FRT of 1093 K (820 °C) produced better combinations of strength and toughness as a consequence of a higher degree of pancaking in the austenite. Removal of boron lowered the 34 J/cm2 Charpy-V impact toughness transition temperature from 206 K to 158 K (-67 °C to -115 °C) when the finishing rolling temperature of 1093 K (820 °C) was used without any loss in the strength values compared to the boron-bearing steel. This was due to the finer and more uniform grain structure in the boron-free steel. Contrary to expectations, the difference was not caused by the formation of borocarbide precipitates, as verified by transmission electron microscopy (TEM) investigations, but through the grain coarsening effect of boron.

Shear bond strength between an indirect composite layering material and feldspathic porcelain-coated zirconia ceramics.

Science.gov (United States)

Fushiki, Ryosuke; Komine, Futoshi; Blatz, Markus B; Koizuka, Mai; Taguchi, Kohei; Matsumura, Hideo

2012-10-01

This study aims to evaluate the effect of both feldspathic porcelain coating of zirconia frameworks and priming agents on shear bond strength between an indirect composite material and zirconia frameworks. A total of 462 airborne-particle-abraded zirconia disks were divided into three groups: untreated disks (ZR-AB), airborne-particle-abraded zirconia disks coated with feldspathic porcelain, (ZR-PO-AB), and hydrofluoric acid-etched zirconia disks coated with feldspathic porcelain (ZR-PO-HF). Indirect composite (Estenia C&B) was bonded to zirconia specimens with no (CON) or one of four priming agents--Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB + activator), Estenia Opaque primer, or Porcelain Liner M Liquid B (PLB)--with or without an opaque material (Estenia C&B Opaque). All specimens were tested for shear bond strength before and after 20,000 thermocycles. The Steel-Dwass test and Mann-Whitney U test were used to compare shear bond strength. In ZR-AB specimens, the initial bond strength of the CPB and CPB + Activator groups was significantly higher as compared with the other three groups (P material, bond strength was significantly lower in ZR-AB specimens than in ZR-PO-AB and ZR-PO-HF specimens (P composite to zirconia independent of surface treatment. The use of a silane coupling agent and opaque material yields durable bond strength between the indirect composite and feldspathic-porcelain-coated zirconia. The results of the present study suggest that feldspathic porcelain coating of zirconia frameworks is an effective method to obtain clinically acceptable bond strengths of a layering indirect composite material to a zirconia framework.

Ultimate strength and ductility of steel reinforced concrete beam-columns

International Nuclear Information System (INIS)

Shohara, Ryoichi

1991-01-01

The ultimate strength and ductility of SRC beam-columns are investigated using the data gathered in Architectural Institute of Japan. Though the simple superposed strength formula in AIJ standard underestimates the strength of SRC beam-column failed in flexure, the generalized superposed strength formula estimates it satisfactory. The strength formula in AIJ standard does not good agreement with test data. The SRC beam-column failed in shear has almost equalductility with that failed in flexure owing to the encased steel. Author presents the formulas which estimate the ultimate deformation angle for SRC beam-columns. (author)

Undrained shear strength determination and correlations on Søvind Marl

DEFF Research Database (Denmark)

Grønbech, Gitte Lyng; Nielsen, Benjaminn Nordahl

2016-01-01

on both the preconsolidation and the undrained shear strength. Two apparent values of the preconsolidation stresses can be determined due to the fissured structure (Grønbech et al. 2015) which also considerably decreases the undrained shear strength. Determination of shear strength of fissured clay...... is done through field testing or triaxial testing. Christensen and Hansen (1959) tested fissured Danish Oligocene clay and found the undrained shear strength, Su, be approximately 1/3 of the measured field vane shear strength, cfv. This correlation has since been used in Danish geotechnical practice...

Assessment of high-strength stainless steel weldments for fusion energy applications

International Nuclear Information System (INIS)

Alexander, D.J.; Goodwin, G.M.

1991-01-01

Primary design considerations for the Compact Ignition Tokomak fusion reactor magnet cases are yield strength and toughness in the temperature range from liquid nitrogen to room temperature (77 to 300K). Type 21-6-9 stainless steel, also known as Nitronic 40, is the proposed alloy for this application. This study documented the mechanical properties, including tensile yield strength and Charpy V-notch impact toughness, at 77K and room temperature, of weldments made using seven different filler metals. Six welds were made with filler metal added as cold filler wire using the argon-shielded gas tungsten arc welding process. Filler metals included Nitronic 35W and 40W, 21-6-9, ERNiCr-3 (Inconel 82), ERNiCrMo-3 (Inconel 625), and Inconel 625 PLUS. All welds were prepared with a double-groove butt-weld geometry. At room temperature, all of the filler metals had yield strengths which exceeded the base metal. However, at 77K only the Nitronics and the 21-6-9 filler metals exceeded the base metals, and the Inconel filler metals were significantly weaker. The impact properties of the weld metals were very good at room temperature, with the exception of Inconel 625. At 77K, impact toughness was greatly reduced for all of the filler metals with the exception of Inconel 82. This alloy had excellent toughness at both temperatures. The severe drop in the impact toughness of the Nitronic and 21-6-9 filler metals was attributed to the amount of ferrite present in these welds. At 77K, fracture occurred by a cleavage mechanism in the ferrite regions which allowed the crack to grow readily. The fully austenitic Inconel 82 material fractured by a microvoid coalescence mode at either test temperature. These results indicate that the Inconel 82 filler metal is the preferred material for welding 21-6-o stainless steel for this application

Fatigue strength of socket welded pipe joint

International Nuclear Information System (INIS)

Iida, K.; Matsuda, F.; Sato, M.; Higuchi, M.; Nakagawa, A.

1994-01-01

Fully reversed four point bending fatigue tests were carried out of small diameter socket welded joints made of carbon steels. Experimental parameters are pipe diameter, thickness of pipe and socket wall, throat depth and shape of fillet welds, slip-on and diametral gaps in the socket welding, lack of penetration at the root of fillet welds, and peening of fillet welds. In most cases a fatigue crack started from the root of the fillet, but in the case of higher stress amplitude, it tended to start from the toe of fillet. The standard socket welded joint of 50 mm diameter showed relatively low fatigue strength, 46 MPa in stress amplitude at the 10 7 cycles failure life. This value corresponds to about 1/5 of that of the smoothed base metal specimens in axial fatigue. The fatigue strength showed decrease with increasing pipe diameter, and increase with increasing the thickness of pipe and socket wall. The effects of throat depth and shape of fillet welds on fatigue strength were not significant. Contrary to the expectation, the fatigue strength of the socket welded joint without slip-on gap is higher than that of the joint with the normal gap. A lack of penetration at the root deleteriously reduced fatigue strength, showing 14 MPa in stress amplitude at the 10 7 cycles failure life for the 50 mm diameter socket joint. (orig.)

The adhesive strength and initial viscosity of denture adhesives.

Science.gov (United States)

Han, Jian-Min; Hong, Guang; Dilinuer, Maimaitishawuti; Lin, Hong; Zheng, Gang; Wang, Xin-Zhi; Sasaki, Keiichi

2014-11-01

To examine the initial viscosity and adhesive strength of modern denture adhesives in vitro. Three cream-type denture adhesives (Poligrip S, Corect Cream, Liodent Cream; PGS, CRC, LDC) and three powder-type denture adhesives (Poligrip Powder, New Faston, Zanfton; PGP, FSN, ZFN) were used in this study. The initial viscosity was measured using a controlled-stress rheometer. The adhesive strength was measured according to ISO-10873 recommended procedures. All data were analyzed independently by one-way analysis of variance combined with a Student-Newman-Keuls multiple comparison test at a 5% level of significance. The initial viscosity of all the cream-type denture adhesives was lower than the powder-type adhesives. Before immersion in water, all the powder-type adhesives exhibited higher adhesive strength than the cream-type adhesives. However, the adhesive strength of cream-type denture adhesives increased significantly and exceeded the powder-type denture adhesives after immersion in water. For powder-type adhesives, the adhesive strength significantly decreased after immersion in water for 60 min, while the adhesive strength of the cream-type adhesives significantly decreased after immersion in water for 180 min. Cream-type denture adhesives have lower initial viscosity and higher adhesive strength than powder type adhesives, which may offer better manipulation properties and greater efficacy during application.

Wireless Concrete Strength Monitoring of Wind Turbine Foundations

Directory of Open Access Journals (Sweden)

Marcus Perry

2017-12-01

Full Text Available Wind turbine foundations are typically cast in place, leaving the concrete to mature under environmental conditions that vary in time and space. As a result, there is uncertainty around the concrete’s initial performance, and this can encourage both costly over-design and inaccurate prognoses of structural health. Here, we demonstrate the field application of a dense, wireless thermocouple network to monitor the strength development of an onshore, reinforced-concrete wind turbine foundation. Up-to-date methods in fly ash concrete strength and maturity modelling are used to estimate the distribution and evolution of foundation strength over 29 days of curing. Strength estimates are verified by core samples, extracted from the foundation base. In addition, an artificial neural network, trained using temperature data, is exploited to demonstrate that distributed concrete strengths can be estimated for foundations using only sparse thermocouple data. Our techniques provide a practical alternative to computational models, and could assist site operators in making more informed decisions about foundation design, construction, operation and maintenance.

Compressive strength, flexural strength and thermal conductivity of autoclaved concrete block made using bottom ash as cement replacement materials

International Nuclear Information System (INIS)

Wongkeo, Watcharapong; Thongsanitgarn, Pailyn; Pimraksa, Kedsarin; Chaipanich, Arnon

2012-01-01

Highlights: ► Autoclaved aerated concrete were produced using coal bottom ash as a cement replacement material. ► Coal bottom ash was found to enhance concrete strengths. ► Thermal conductivity of concrete was not significantly affected. ► X-ray diffraction and thermal analysis show tobermorite formation. -- Abstract: The bottom ash (BA) from Mae Moh power plant, Lampang, Thailand was used as Portland cement replacement to produce lightweight concrete (LWC) by autoclave aerated concrete method. Portland cement type 1, river sand, bottom ash, aluminium powder and calcium hydroxide (Ca(OH) 2 ) were used in this study. BA was used to replace Portland cement at 0%, 10%, 20% and 30% by weight and aluminium powder was added at 0.2% by weight in order to produce the aerated concrete. Compressive strength, flexural and thermal conductivity tests were then carried out after the concrete were autoclaved for 6 h and left in air for 7 days. The results show that the compressive strength, flexural strength and thermal conductivity increased with increased BA content due to tobermorite formation. However, approximately, 20% increase in both compressive (up to 11.61 MPa) and flexural strengths (up to 3.16 MPa) was found for mixes with 30% BA content in comparison to just around 6% increase in the thermal conductivity. Thermogravimetry analysis shows C–S–H formation and X-ray diffraction confirm tobermorite formation in bottom ash lightweight concrete. The use of BA as a cement replacement, therefore, can be seen to have the benefit in enhancing strength of the aerated concrete while achieving comparatively low thermal conductivity when compared to the results of the control Portland cement concrete.

Normative values of eccentric hip abduction strength in novice runners

DEFF Research Database (Denmark)

Jørgensen, Daniel Ramskov; Pedersen, Mette Broen; Kastrup, Kristrian

2014-01-01

.354) Nm/kg. CONCLUSION: Normative values for maximal eccentric hip abduction strength in novice runners can be calculated by taking into account the differences in strength across genders and the decline in strength that occurs with increasing age. Age and gender were associated with maximal eccentric hip...... associated with maximal eccentric hip abduction strength from a univariate analysis were included in a multivariate linear regression model. Based on the results from the regression model, a regression equation for normative hip abduction strength is presented. RESULTS: A SIGNIFICANT DIFFERENCE IN MAXIMAL...... was found, p gender. Based on this, the equation to calculate normative values for relative eccentric hip abduction strength became: (1.600 + (age * -0.005) + (gender (1 = male / 0 = female) * 0.215) ± 1 or 2 * 0...

Three-Sheet Spot Welding of Advanced High-Strength Steels

DEFF Research Database (Denmark)

Nielsen, Chris Valentin; Friis, Kasper Storgaard; Zhang, W.

2011-01-01

The automotive industry has introduced the three-layer weld configuration, which represents new challenges compared to normal two-sheet lap welds. The process is further complicated by introducing high-strength steels in the joint. The present article investigates the weldability of thin, low....... The weld mechanisms are analyzed numerically and compared with metallographic analyses showing how the primary bonding mechanism between the thin, low-carbon steel sheet and the thicker sheet of high-strength steel is solid-state bonding, whereas the two high-strength steels are joined by melting, forming...... a weld nugget at their mutual interface. Despite the absence of the typical fusion nugget through the interface between the low-carbon steel and high-strength steel, the weld strengths obtained are acceptable. The failure mechanism in destructive testing is ductile fracture with plug failure....

Hand Strength, Handwriting, and Functional Skills in Children With Autism.

Science.gov (United States)

Alaniz, Michele L; Galit, Eleanor; Necesito, Corina Isabel; Rosario, Emily R

2015-01-01

To establish hand strength development trends in children with autism and to investigate correlations between grip and pinch strength, components of handwriting, and functional activities in children with and without autism. Fifty-one children were divided into two groups: typically developing children and children on the autism spectrum. Each child completed testing for pinch and grip strength, handwriting legibility, pencil control, and independence in functional activities. The children with autism followed the same strength development trends as the typically developing children. Grip strength correlated with pencil control in both groups and with handwriting legibility in the typically developing children but not in the children with autism. Grip and pinch strength correlated with independence with functional activities in both groups. This study provides evidence that grip and pinch strength are important components in developing pencil control, handwriting legibility, and independence with functional fine motor tasks. Copyright © 2015 by the American Occupational Therapy Association, Inc.

Chairside CAD/CAM materials. Part 2: Flexural strength testing.

Science.gov (United States)

Wendler, Michael; Belli, Renan; Petschelt, Anselm; Mevec, Daniel; Harrer, Walter; Lube, Tanja; Danzer, Robert; Lohbauer, Ulrich

2017-01-01

Strength is one of the preferred parameters used in dentistry for determining clinical indication of dental restoratives. However, small dimensions of CAD/CAM blocks limit reliable measurements with standardized uniaxial bending tests. The objective of this study was to introduce the ball-on-three-ball (B3B) biaxial strength test for dental for small CAD/CAM block in the context of the size effect on strength predicted by the Weibull theory. Eight representative chairside CAD/CAM materials ranging from polycrystalline zirconia (e.max ZirCAD, Ivoclar-Vivadent), reinforced glasses (Vitablocs Mark II, VITA; Empress CAD, Ivoclar-Vivadent) and glass-ceramics (e.max CAD, Ivoclar-Vivadent; Suprinity, VITA; Celtra Duo, Dentsply) to hybrid materials (Enamic, VITA; Lava Ultimate, 3M ESPE) have been selected. Specimens were prepared with highly polished surfaces in rectangular plate (12×12×1.2mm 3 ) or round disc (Ø=12mm, thickness=1.2mm) geometries. Specimens were tested using the B3B assembly and the biaxial strength was determined using calculations derived from finite element analyses of the respective stress fields. Size effects on strength were determined based on results from 4-point-bending specimens. A good agreement was found between the biaxial strength results for the different geometries (plates vs. discs) using the B3B test. Strength values ranged from 110.9MPa (Vitablocs Mark II) to 1303.21MPa (e.max ZirCAD). The strength dependency on specimen size was demonstrated through the calculated effective volume/surface. The B3B test has shown to be a reliable and simple method for determining the biaxial strength restorative materials supplied as small CAD/CAM blocks. A flexible solution was made available for the B3B test in the rectangular plate geometry. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Bond strength and microleakage of current dentin adhesives.

Science.gov (United States)

Fortin, D; Swift, E J; Denehy, G E; Reinhardt, J W

1994-07-01

The purpose of this in vitro study was to evaluate shear bond strengths and microleakage of seven current-generation dentin adhesive systems. Standard box-type Class V cavity preparations were made at the cemento-enamel junction on the buccal surfaces of eighty extracted human molars. These preparations were restored using a microfill composite following application of either All-Bond 2 (Bisco), Clearfil Liner Bond (Kuraray), Gluma 2000 (Miles), Imperva Bond (Shofu), OptiBond (Kerr), Prisma Universal Bond 3 (Caulk), Scotchbond Multi-Purpose (3M), or Scotchbond Dual-Cure (3M) (control). Lingual dentin of these same teeth was exposed and polished to 600-grit. Adhesives were applied and composite was bonded to the dentin using a gelatin capsule technique. Specimens were thermocycled 500 times. Shear bond strengths were determined using a universal testing machine, and microleakage was evaluated using a standard silver nitrate staining technique. Clearfill Liner Bond and OptiBond, adhesive systems that include low-viscosity, low-modulus intermediate resins, had the highest shear bond strengths (13.3 +/- 2.3 MPa and 12.9 +/- 1.5 MPa, respectively). Along with Prisma Universal Bond 3, they also had the least microleakage at dentin margins of Class V restorations. No statistically significant correlation between shear bond strength and microleakage was observed in this study. Adhesive systems that include a low-viscosity intermediate resin produced the high bond strengths and low microleakage. Similarly, two materials with bond strengths in the intermediate range had significantly increased microleakage, and one material with a bond strength in the low end of the spectrum exhibited microleakage that was statistically greater. Thus, despite the lack of statistical correlation, there were observable trends.

Hamstrings strength imbalance in professional football (soccer) players in Australia.

Science.gov (United States)

Ardern, Clare L; Pizzari, Tania; Wollin, Martin R; Webster, Kate E

2015-04-01

The aim of this study was to describe the isokinetic thigh muscle strength profile of professional male football players in Australia. Concentric (60° and 240°·s(-1)) and eccentric (30° and 120°·s(-1)) hamstrings and quadriceps isokinetic strength was measured with a HUMAC NORM dynamometer. The primary variables were bilateral concentric and eccentric hamstring and quadriceps peak torque ratios, concentric hamstring-quadriceps peak torque ratios, and mixed ratios (eccentric hamstring 30°·s(-1) ÷ concentric quadriceps 240°·s(-1)). Hamstring strength imbalance was defined as deficits in any 2 of: bilateral concentric hamstring peak torque ratio imbalance. Athletes with strength imbalance had significantly reduced concentric and eccentric bilateral hamstring peak torque ratios at all angular velocities tested; and reduced eccentric quadriceps peak torque (30°·s(-1)) in their stance leg, compared with those without strength imbalance. Approximately, 1 in 4 players had preseason hamstring strength imbalance; and all strength deficits were observed in the stance leg. Concentric and eccentric hamstrings strength imbalance may impact in-season football performance and could have implications for the future risk of injury.

Combined strength and endurance training in competitive swimmers.

Science.gov (United States)

Aspenes, Stian; Kjendlie, Per-Ludvik; Hoff, Jan; Helgerud, Jan

2009-01-01

A combined intervention of strength and endurance training is common practice in elite swimming training, but the scientific evidence is scarce. The influences between strength and endurance training have been investigated in other sports but the findings are scattered. Some state the interventions are negative to each other, some state there is no negative relationship and some find bisected and supplementary benefits from the combination when training is applied appropriately. The aim of this study was to investigate the impact of a combined intervention among competitive swimmers. 20 subjects assigned to a training intervention group (n = 11) or a control group (n = 9) from two different teams completed the study. Anthropometrical data, tethered swimming force, land strength, performance in 50m, 100m and 400m, work economy, peak oxygen uptake, stroke length and stroke rate were investigated in all subjects at pre- and post-test. A combined intervention of maximal strength and high aerobic intensity interval endurance training 2 sessions per week over 11 weeks in addition to regular training were used, while the control group continued regular practice with their respective teams. The intervention group improved land strength, tethered swimming force and 400m freestyle performance more than the control group. The improvement of the 400m was correlated with the improvement of tethered swimming force in the female part of the intervention group. No change occurred in stroke length, stroke rate, performance in 50m or 100m, swimming economy or peak oxygen uptake during swimming. Two weekly dry-land strength training sessions for 11 weeks increase tethered swimming force in competitive swimmers. This increment further improves middle distance swimming performance. 2 weekly sessions of high- intensity interval training does not improve peak oxygen uptake compared with other competitive swimmers. Key pointsTwo weekly sessions of dry land strength training improves the

High strength cast aluminum alloy development

Science.gov (United States)

Druschitz, Edward A.

The goal of this research was to understand how chemistry and processing affect the resulting microstructure and mechanical properties of high strength cast aluminum alloys. Two alloy systems were investigated including the Al-Cu-Ag and the Al-Zn-Mg-Cu systems. Processing variables included solidification under pressure (SUP) and heat treatment. This research determined the range in properties that can be achieved in BAC 100(TM) (Al-Cu micro-alloyed with Ag, Mn, Zr, and V) and generated sufficient property data for design purposes. Tensile, stress corrosion cracking, and fatigue testing were performed. CuAl2 and Al-Cu-Fe-Mn intermetallics were identified as the ductility limiting flaws. A solution treatment of 75 hours or longer was needed to dissolve most of the intermetallic CuAl 2. The Al-Cu-Fe-Mn intermetallic was unaffected by heat treatment. These results indicate that faster cooling rates, a reduction in copper concentration and a reduction in iron concentration might increase the ductility of the alloy by decreasing the size and amount of the intermetallics that form during solidification. Six experimental Al-Zn-Mg-Cu series alloys were produced. Zinc concentrations of 8 and 12wt% and Zn/Mg ratios of 1.5 to 5.5 were tested. Copper was held constant at 0.9%. Heat treating of the alloys was optimized for maximum hardness. Al-Zn-Mg-Cu samples were solution treated at 441°C (826°F) for 4 hours before ramping to 460°C (860°F) for 75 hours and then aged at 120°C (248°F) for 75 hours. X-ray diffraction showed that the age hardening precipitates in most of these alloys was the T phase (Mg32Zn 31.9Al17.1). Tensile testing of the alloys showed that the best mechanical properties were obtained in the lowest alloy condition. Chilled Al-8.2Zn-1.4Mg-0.9Cu solidified under pressure resulted in an alloy with a yield strength of 468MPa (68ksi), tensile strength of 525MPa (76ksi) and an elongation of 9%.

Quadriceps Strength in Patients With Isolated Cartilage Defects of the Knee: Results of Isokinetic Strength Measurements and Their Correlation With Clinical and Functional Results.

Science.gov (United States)

Hirschmüller, Anja; Andres, Tasja; Schoch, Wolfgang; Baur, Heiner; Konstantinidis, Lukas; Südkamp, Norbert P; Niemeyer, Philipp

2017-05-01

Recent studies have found a significant deficit of maximum quadriceps strength after autologous chondrocyte implantation (ACI) of the knee. However, it is unclear whether muscular strength deficits in patients with cartilage damage exist prior to operative treatment. To isokinetically test maximum quadriceps muscle strength and quantify the impact of possible strength deficits on functional and clinical test results. Cross-sectional study; Level of evidence, 3. To identify clinically relevant muscular strength deficits, 24 patients (5 females, 19 males; mean age, 34.5 years; body mass index, 25.9 kg/m 2 ) with isolated cartilage defects (mean onset, 5.05 years; SD, 7.8 years) in the knee joint underwent isokinetic strength measurements. Maximal quadriceps strength was recorded in 3 different testing modes: pure concentric contraction (flexors and extensors alternating work; con1), concentric-eccentric (only the extensors work concentrically and eccentrically; con2), and eccentric contraction in the alternating mode (ecc). Results were compared for functional performance (single-leg hop test), pain scales (visual analog scale [VAS], numeric rating scale [NRS]), self-reported questionnaires (International Knee Documentation Committee [IKDC], Knee Injury and Osteoarthritis Outcome Scale [KOOS]), and defect size (cm 2 ). Compared with the uninjured leg, significantly lower quadriceps strength was detected in the injured leg in all isokinetic working modes (con1 difference, 27.76 N·m [SD 17.47; P = .003]; con2 difference, 21.45 N·m [SD, 18.45; P =.025]; ecc difference, 29.48 N·m [SD, 21.51; P = .001]), with the largest deficits found for eccentric muscle performance. Moderate negative correlations were observed for the subjective pain scales NRS and VAS. The results of the IKDC and KOOS questionnaires showed low, nonsignificant correlations with findings in the isokinetic measurement. Moreover, defect sizes (mean, 3.13 cm 2 ) were of no importance regarding the

Enhancing paper strength by optimizing defect configuration

Science.gov (United States)

J.M. Considine; W. Skye; W. Chen; D. Matthys; David W. Vahey; K. Turner; R. Rowlands

2009-01-01

Poor formation in paper, as denoted by large local variation of mass, tends to reduce maximum tensile strength but has not been well characterized. The effect of grammage variation on tensile strength was studied by introducing carefully placed holes in tensile specimens made of three different paper materials. Previous researchers demonstrated that the point-stress...

Topological strength of magnetic skyrmions

Energy Technology Data Exchange (ETDEWEB)

Bazeia, D.; Ramos, J.G.G.S.; Rodrigues, E.I.B.

2017-02-01

This work deals with magnetic structures that attain integer and half-integer skyrmion numbers. We model and solve the problem analytically, and show how the solutions appear in materials that engender distinct, very specific physical properties, and use them to describe their topological features. In particular, we found a way to model skyrmion with a large transition region correlated with the presence of a two-peak skyrmion number density. Moreover, we run into the issue concerning the topological strength of a vortex-like structure and suggest an experimental realization, important to decide how to modify and measure the topological strength of the magnetic structure.