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Sample records for bonding progressively strengthens

  1. Diffusion bonding of the oxide dispersion strengthened steel PM2000

    Science.gov (United States)

    Sittel, Wiebke; Basuki, Widodo W.; Aktaa, Jarir

    2013-11-01

    Ferritic oxide dispersion strengthened (ODS) steels are well suited as structural materials, e.g. for claddings in fission reactors and for plasma facing components in fusion power plants due to their high mechanical and oxidation stability at high temperatures and their high irradiation resistance. PM2000 is an iron based ODS ferritic steel with homogeneously distributed nanometric yttria particles. Melting joining techniques are not suitable for such ODS materials because of the precipitation and agglomeration of the oxide particles and hence the loss of their strengthening effect. Solid state diffusion bonding is thus chosen to join PM2000 and is investigated in this work with a focus on oxide particles. The diffusion bonding process is aided by the computational modeling, including the influence of the ODS particles. For modeling the microstructure stability and the creep behavior of PM2000 at various, diffusion bonding relevant temperatures (50-80% Tm) are investigated. Particle distribution (TEM), strength (tensile test) and toughness (Charpy impact test) obtained at temperatures relevant for bonding serve as input for the prediction of optimal diffusion bonding parameters. The optimally bonded specimens show comparable strength and toughness relative to the base material.

  2. Diffusion bonding of the oxide dispersion strengthened steel PM2000

    International Nuclear Information System (INIS)

    Ferritic oxide dispersion strengthened (ODS) steels are well suited as structural materials, e.g. for claddings in fission reactors and for plasma facing components in fusion power plants due to their high mechanical and oxidation stability at high temperatures and their high irradiation resistance. PM2000 is an iron based ODS ferritic steel with homogeneously distributed nanometric yttria particles. Melting joining techniques are not suitable for such ODS materials because of the precipitation and agglomeration of the oxide particles and hence the loss of their strengthening effect. Solid state diffusion bonding is thus chosen to join PM2000 and is investigated in this work with a focus on oxide particles. The diffusion bonding process is aided by the computational modeling, including the influence of the ODS particles. For modeling the microstructure stability and the creep behavior of PM2000 at various, diffusion bonding relevant temperatures (50–80% Tm) are investigated. Particle distribution (TEM), strength (tensile test) and toughness (Charpy impact test) obtained at temperatures relevant for bonding serve as input for the prediction of optimal diffusion bonding parameters. The optimally bonded specimens show comparable strength and toughness relative to the base material

  3. Reinforced concrete beams strengthened with carbon fiber reinforced polymer by friction hybrid bond technique: Experimental investigation

    International Nuclear Information System (INIS)

    Highlights: • Friction Hybrid Bonded FRP Technique is conducted to strengthen RC beams. • Six specimens with different reinforced methods were tested. • The strengthened effects of different strengthening methods were discussed. • The results obtained from the FEA and experiments are agreed very well. - Abstract: Carbon fiber reinforced polymer (CFRP) can be used to strengthen the reinforced concrete (RC) beams. But premature debonding is the main failure model in ordinary bond technique, and the strengthening effect is limited. In order to improve bonding and restricting sliding displacement, Friction Hybrid Bonded FRP Technique (FHB-FRP) is developed. Six simple-span RC specimen beams with different strengthened methods were tested in four-point bending. The experiment results indicate that FRP debonding can be effectively prevented by the FHB-FRP strengthened beam. The ultimate load-carrying capacity of the specimen strengthened by FHB-FRP technique is able to increase by a factor of 2.13 times compared with the beam strengthened with ordinary bond technique (U-jacketing technique). In addition, the cracking and yielding loads are improved more significantly by FHB-FRP technique than U-jacketing technique. Specimens strengthened with FHB-FRP technique have cracks with a more limited distribution and width. Finally, the finite element method (FEM) is conducted to simulate the behavior of the test specimens. The results obtained from the finite element method are compared with experiment. Excellent agreements have been achieved in the comparison of results

  4. Meso-scale three-dimensional modeling of bond in FRP-strengthened masonry

    OpenAIRE

    Ghiassi, Bahman; Oliveira, Daniel V.; Lourenço, Paulo B.; Marcari, Giancarlo

    2012-01-01

    Performance of masonry elements externally strengthened with fiber reinforced polymers (FRPs) is intrinsically dependent on the bond behavior between the composite material and masonry substrate. Therefore, a sound understanding of the interface behavior is crucial at the design stage. In this paper, a three-dimensional model based on the smeared crack modeling approach is presented for investigating the bond behavior in FRP-strengthened masonry elements. The threedimensional aspects of bond ...

  5. Structural improvement of strengthened deck panels with externally bonded plates

    International Nuclear Information System (INIS)

    Concrete bridge decks require eventual replacement and rehabilitation due to decreasing load-carrying capacity. This paper compares different strengthening design procedures that improve the usability and structural performance of bridge decks. The failure characteristics of bridge decks strengthened with various materials such as carbon fiber sheet, glass fiber sheet, steel plate, and grid CFRP and GFRP are analyzed, and the theoretical load-carrying capacities are evaluated using traditional beam and yield line theory, and punching shear analysis. The strengthening materials increase the punching shear strength of the deck and change the failure mode of the strengthened panel

  6. Mineral-Based Bonding of Carbon FRP to Strengthen Concrete Structures

    DEFF Research Database (Denmark)

    Täljsten, Björn; Blanksvärd, T.

    2007-01-01

    therefore be strengthened before it can be used. Different methods to retrofit with FRPs also exist, such as bonding of plates or sheets, with their use of epoxy as the bonding agent being the commonality. Epoxy provides very good bond to concrete and is durable and resistant to most environments in the...

  7. Towards Rational Design Method for Strengthening of Concrete Structures by External Bonding

    OpenAIRE

    Furuuchi H.; Zhang D; Ueda T

    2012-01-01

    Many infrastructures need to be repaired or strengthened due to various reasons, such as unexpected deterioration and changes in performance requirement. This paper presents the following recent achievements by the authors’ group on design method for flexural strengthening of concrete structures by external bonding; (i) fracture characteristics of interface between substrate concrete and cementitious overlay, (ii) crack spacing of flexural strengthened beams, which affects debonding strength,...

  8. Diffusion Bonding and Characterization of a Dispersion Strengthened Aluminum Alloy

    Science.gov (United States)

    Cooke, Kavian Omar

    Aluminum metal matrix composites (Al-MMC's) containing silicon carbide or alumina particle reinforcements are used extensively in automotive and aircraft industries. The addition of a reinforcing phase has led to significant improvements in the mechanical properties of these alloys. However, despite substantial improvements in the properties, the lack of a reliable joining method has restricted their full potential. The differences in physical and metallurgical properties between the ceramic phase and the Al-MMC, prevents the successful application of the fusion welding processes, conventionally used for joining monolithic aluminum alloys. Therefore, alternative techniques that prevent microstructural changes in the base metal need to be developed. In this study, the transient liquid phase diffusion bonding and eutectic bonding of a particle reinforced Al 6061-MMC was investigated to identify a method that could control particle segregation within the joint and increase the final joint strength. The results showed that TLP bonding using Ni-foil was possible at 600°C for 10 minutes using a pressure of 0.01 MPa. However, characterization of the bond interface showed a wide particle segregated zone due to the "pushing effect" of the solid/liquid interface during isothermal solidification stage of bonding. The presence of this particle segregated zone was shown to cause low joint strengths. In order to overcome these problems, TLP bonding was performed using electrodeposited coatings of Ni and Ni-Al 2O3 as a way of controlling the volume of eutectic liquid formed at the joint. Theoretical and experimental work showed that the use of thin coatings was successful in reducing the width of the segregated zone formed at the joint and this had the effect of increasing joint shear strength values. Furthermore, lower bonding temperature could also be used as a method of reducing particle segregation and therefore, a Cu-Sn interlayer was used to form a eutectic bond. The

  9. Modeling and experimental evaluation of the diffusion bonding of the oxide dispersion strengthened steel PM2000

    Science.gov (United States)

    Sittel, Wiebke; Basuki, Widodo W.; Aktaa, Jarir

    2015-10-01

    A modeling based optimization process of the solid state diffusion bonding is presented for joining ferritic oxide dispersion strengthened steels PM2000. An optimization study employing varying bonding temperatures and pressures results in almost the same strength and toughness of the bonded compared to the as received material. TEM investigations of diffusion bonded samples show a homogeneous distribution of oxide particles at the bonding seam similar to that in the bulk. Hence, no loss in strength or creep resistance due to oxide particle agglomeration is found, as verified by the mechanical properties observed for the joint.

  10. Towards Rational Design Method for Strengthening of Concrete Structures by External Bonding

    Directory of Open Access Journals (Sweden)

    Furuuchi H.

    2012-01-01

    Full Text Available Many infrastructures need to be repaired or strengthened due to various reasons, such as unexpected deterioration and changes in performance requirement. This paper presents the following recent achievements by the authors’ group on design method for flexural strengthening of concrete structures by external bonding; (i fracture characteristics of interface between substrate concrete and cementitious overlay, (ii crack spacing of flexural strengthened beams, which affects debonding strength, (iii strengths of intermediate crack (IC debonding and end peeling, (iv strength of concrete cover separation, and (v effectiveness of strengthening by external bonding. A unified approach for flexural strengthening by steel plate, fiber reinforced polymer lami¬nate and cementitious overlay, for both intermediate crack (IC debonding, including end peeling, and concrete cover separation is pre¬sented with consideration of crack spacing in the streng¬thened members. Appropriate interfacial rough¬¬¬ness to achieve efficient interface bond property is clari¬fied and the concept of effectiveness of strengthen¬ing is proposed for better strengthening design.

  11. Strengthening of RC Beams Using Externally Bonded Reinforcement Combined with Near-Surface Mounted Technique

    Directory of Open Access Journals (Sweden)

    Kh Mahfuz ud Darain

    2016-07-01

    Full Text Available This study investigates the flexural behaviour of reinforced concrete (RC beams strengthened through the combined externally bonded and near-surface mounted (CEBNSM technique. The externally bonded reinforcement (EBR and near-surface mounted (NSM techniques are popular strengthening solutions, although these methods often demonstrate premature debonding failure. The proposed CEBNSM technique increases the bond area of the concrete–carbon fibre reinforced polymer (CFRP interface, which can delay the debonding failure. This technique is appropriate when any structure has a narrow cross-sectional width or is in need of additional flexural capacity that an individual technique or material cannot attain. An experimental test matrix was designed with one control and five strengthened RC beams to verify the performance of the proposed technique. The strengthening materials were CFRP bar as NSM reinforcement combined with CFRP fabric as EBR material. The test variables were the diameter of the NSM bars (8 and 10 mm, the thickness of the CFRP fabrics (one and two layers and the U-wrap anchorage. The strengthened beams showed enhancement of ultimate load capacity, stiffness, cracking behaviour, and strain compatibility. The ultimate capacity of the CEBNSM-strengthened beams increased from 71% to 105% compared to that of the control beam. A simulation method based on the moment-rotation approach was also presented to predict the behaviour of CEBNSM-strengthened RC beams.

  12. Electric Contact Strengthening to Improve the Bonding Between WC-Co Coating and 45# Steel Substrate

    Science.gov (United States)

    Wang, Yalin; Zhu, Shigen; Gu, Weisheng; Qi, Xiaoben

    2010-09-01

    Adhesion between thermally sprayed coating and the substrate is a type of mechanical bonding. In many cases, the adhesion strength is relatively low. In this study, an electric contact surface strengthening method was used to improve the bonding between thermally sprayed WC/Co coating and 45# steel substrate. Electric contact strengthening equipment was made for this research. Localization of resistive heating was obtained by passing 12-18 kA current through the contact between the electrode and the workpiece, the small size of the contact imposed a severe constriction on the current causing intense resistive heating the contact. In this way, the bonding way between the WC/Co coating and the 45# steel substrate would be changed from mechanical bonding to metallurgical bonding. Orthogonal array design was applied to select the optimum conditions. The effects of different factors and levels have been studied using a statistic method.

  13. Bond and flexural behavior of concrete elements strengthened with NSM CFRP laminate strips under fatigue loading

    OpenAIRE

    Fernandes, Pedro Miguel Gomes; Silva, Patrícia; Sena-Cruz, José

    2015-01-01

    This paper presents the results of an experimental research on bond and flexural behavior of concrete elements strengthened with carbon fiber reinforced polymer (CFRP) laminate strips under fatigue loading conditions, applied according to the near-surface mounted (NSM) strengthening technique. Long-term performance of the NSM system could be compromised by fatigue loading, which may result in deterioration and weakening of individual components (steel, FRP, concrete), or loss of b...

  14. Bond Behavior of Historical Clay Bricks Strengthened with Steel Reinforced Polymers (SRP

    Directory of Open Access Journals (Sweden)

    Elio Sacco

    2011-03-01

    Full Text Available In the strengthening interventions of past and historical masonry constructions, the non-standardized manufacture processes, the ageing and the damage of masonry units, could significantly affect the properties of the surfaces where strengthening materials are applied. This aspect requires particular care in evaluating the performance of externally bonded strengthening layers, especially with reference to the detachment mechanism. The bond response of old masonries could be very different from that occurring in new masonry units which are the ones generally considered in most of the bond tests available in technical literature. The aim of the present paper is the study of the bond behavior of historical clay bricks strengthened with steel reinforced polymers (SRP materials. In particular, the results of an experimental study concerning new manufactured clay bricks and old bricks extracted from different historical masonry buildings are presented. The obtained results, particularly in terms of bond resistance, detachment mechanism and strain distributions, are discussed for the purpose of analyzing the peculiarities of the historical bricks in comparison with new manufactured ones. Some considerations on the efficacy of the theoretical formulations of the recent Italian code are also carried out.

  15. Strengthening gold-gold bonds by complexing gold clusters with noble gases

    OpenAIRE

    Ghiringhelli, Luca M.; Levchenko, Sergey V.

    2015-01-01

    We report an unexpectedly strong and complex chemical bonding of rare-gas atoms to neutral gold clusters. The bonding features are consistently reproduced at different levels of approximation within density-functional theory and beyond: from GGA, through hybrid and double-hybrid functionals, up to renormalized second-order perturbation theory. The main finding is that the adsorption of Ar, Kr, and Xe reduces electron-electron repulsion within gold dimer, causing strengthening of the Au-Au bon...

  16. Progressive Damage Analysis of Bonded Composite Joints

    Science.gov (United States)

    Leone, Frank A., Jr.; Girolamo, Donato; Davila, Carlos G.

    2012-01-01

    The present work is related to the development and application of progressive damage modeling techniques to bonded joint technology. The joint designs studied in this work include a conventional composite splice joint and a NASA-patented durable redundant joint. Both designs involve honeycomb sandwich structures with carbon/epoxy facesheets joined using adhesively bonded doublers.Progressive damage modeling allows for the prediction of the initiation and evolution of damage within a structure. For structures that include multiple material systems, such as the joint designs under consideration, the number of potential failure mechanisms that must be accounted for drastically increases the complexity of the analyses. Potential failure mechanisms include fiber fracture, intraply matrix cracking, delamination, core crushing, adhesive failure, and their interactions. The bonded joints were modeled using highly parametric, explicitly solved finite element models, with damage modeling implemented via custom user-written subroutines. Each ply was discretely meshed using three-dimensional solid elements. Layers of cohesive elements were included between each ply to account for the possibility of delaminations and were used to model the adhesive layers forming the joint. Good correlation with experimental results was achieved both in terms of load-displacement history and the predicted failure mechanism(s).

  17. Behavior of reinforced concrete beams strengthened with externally bonded hybrid fiber reinforced polymer systems

    International Nuclear Information System (INIS)

    Highlights: • RC beams strengthened with hybrid FRP sheets. • Carbon and Glass are the used FRP sheets. • Four point bending tests were conducted. • Both strength and ductility had been enhanced. - Abstract: This paper presents an experimental and an analytical investigation of the behavior of Reinforced Concrete (RC) beams strengthened in flexure by means of different combinations of externally bonded hybrid Glass and Carbon Fiber Reinforced Polymer (GFRP/CFRP) sheets. In order to obtain the mechanical properties of the hybrid sheets, multiple tensile coupon tests were conducted. In addition, an experimental program consisting of a control beam and four beams strengthened in flexure with GFRP, CFRP and hybrid FRP sheets was conducted. The series of the RC beams were tested under four point bending to study the flexural effectiveness of the proposed hybrid FRP sheets. The load–deflection response, strain readings at certain locations and associated failure modes of the tested specimens had been recorded. It is observed that the increase in the load capacity of the strengthened beams ranged from 30% to 98% of the un-strengthened control RC beam depending on the combination of the Carbon/Glass sheets. It was also observed that the ductility at failure loads of the beams strengthened with glass and hybrid sheets is higher than that with a single carbon sheet. Hence, the selection of the optimum combination of hybrid sheets can lead to a strengthening material which provides an improved ductility and strength in beam behavior. The load carrying capacity of the tested specimens was then predicted by the ACI 440.2R-08 guidelines. The predicted and measured results were in good agreement, within 5% for the control beam and for beams with one layer of strengthening sheet and between 13% and 17% for beams with two or more layers of hybrid strengthening sheets. Furthermore, an analytical model was developed to predict the load–deflection response of the tested

  18. Nonlinear finite element modeling of concrete deep beams with openings strengthened with externally-bonded composites

    International Nuclear Information System (INIS)

    Highlights: ► A 3D nonlinear FE model is developed of RC deep beams with web openings. ► We used cohesion elements to simulate bond. ► The developed FE model is suitable for analysis of such complex structures. -- Abstract: This paper aims to develop 3D nonlinear finite element (FE) models for reinforced concrete (RC) deep beams containing web openings and strengthened in shear with carbon fiber reinforced polymer (CFRP) composite sheets. The web openings interrupted the natural load path either fully or partially. The FE models adopted realistic materials constitutive laws that account for the nonlinear behavior of materials. In the FE models, solid elements for concrete, multi-layer shell elements for CFRP and link elements for steel reinforcement were used to simulate the physical models. Special interface elements were implemented in the FE models to simulate the interfacial bond behavior between the concrete and CFRP composites. A comparison between the FE results and experimental data published in the literature demonstrated the validity of the computational models in capturing the structural response for both unstrengthened and CFRP-strengthened deep beams with openings. The developed FE models can serve as a numerical platform for performance prediction of RC deep beams with openings strengthened in shear with CFRP composites.

  19. Time-dependent behavior of RC beams strengthened with externally bonded FRP plates: interfacial stresses analysis

    Science.gov (United States)

    Benyoucef, S.; Tounsi, A.; Benrahou, K. H.; Adda Bedia, E. A.

    2007-12-01

    External bonding of fibre reinforced polymer (FRP) composites has becomes a popular technique for strengthening concrete structures all over the world. An important failure mode of such strengthened members is the debonding of the FRP plate from the concrete due to high interfacial stresses near the plate ends. For correctly installed FRP plate, failure will occur within the concrete. Accurate predictions of the interfacial stresses are prerequisite for designing against debonding failures. In particular, the interfacial stresses between a beam and soffit plate within the linear elastic range have been addressed by numerous analytical investigations. In this study, the time-dependent behavior of RC beams bonded with thin composite plate was investigated theoretically by including the effect of the adherend shear deformations. The time effects considered here are those that arise from shrinkage and creep deformations of the concrete. This paper presents an analytical model for the interfacial stresses between RC beam and a thin FRP plate bonded to its soffit. The influence of creep and shrinkage effect relative to the time of the casting and the time of the loading of the beams is taken into account. Numerical results from the present analysis are presented to illustrate the significance of time-dependent of adhesive stresses.

  20. Normal, high and ultra-high modulus carbon fiber-reinforced polymer laminates for bonded and un-bonded strengthening of steel beams

    International Nuclear Information System (INIS)

    Highlights: • Normal, high and ultra-high modulus CFRP laminates for strengthening of steel beams. • Bonded and un-bonded reinforcement systems for steel beams. • Comparisons between the static behavior of the bonded and un-bonded systems. - Abstract: This paper studies the elastic behavior of steel beams strengthened with normal, high and ultra-high modulus CFRP laminates using bonded and un-bonded systems. The elastic behavior of retrofitted beams provides useful information for design of fatigue strengthening systems. A total of seven steel beams including one control unstrengthened beam and six strengthened beams were tested statically until failure in a simply supported four-point bending set-up. The steel beams were retrofitted by normal modulus (NM), high modulus (HM) and ultra-high modulus (UHM) carbon fiber-reinforced polymer (CFRP) laminates with nominal Young’s moduli, ranging from 165 to 440 GPa. Each type of laminate was attached to the steel beams using bonded reinforcement (BR) and un-bonded reinforcement (UR) systems. There is no direct comparison between the BR and the UR systems in the literature. The main goal of the paper is to provide a better understating about the stress distribution along the beam bottom flange when the BR and the UR systems are used for strengthening. All specimens failed due to lateral-torsional buckling (LTB). The effect of different strengthening methods on buckling capacity of the retrofitted specimens was also studied. Experimental results have shown that strengthening using bonded UHM laminates could increase the stiffness of the composite section so that the steel profile has yielded prior to buckling and a larger reinforcement efficacy was then achieved

  1. Flexural behaviour of partially bonded carbon fibre reinforced polymers strengthened concrete beams: Application to fire protection systems design

    International Nuclear Information System (INIS)

    Highlights: • The mechanical behaviour of partially bonded CFRP strengthened beams was modelled. • Two dimensional non-linear finite element models were developed. • Partially bonded beams can present similar flexural strength to fully bonded ones. • Relations between the bonded length and the strength reduction were proposed. • The proposed relations were used for the design of fire protection systems. - Abstract: Recent fire resistance tests on reinforced concrete (RC) beams strengthened with carbon fibre reinforced polymers (CFRP) laminates showed that it is possible to attain considerable fire endurance provided that thermal insulation is applied at the anchorage zones of the strengthening system. With such protection, although the CFRP laminate prematurely debonds in the central part of the beam, it transforms into a cable fixed at the extremities until one of the anchorage zones loses its bond strength. The main objective of this paper is to propose a simplified methodology for the design of fire protection systems for CFRP strengthened-RC beams, which is based on applying thicker insulation at the anchorage zones (promoting the above mentioned “cable behaviour”) and a thinner one at the current zone (avoiding tensile rupture of the carbon fibres). As a first step towards the validation of this methodology, finite element (FE) models were developed to simulate the flexural behaviour at ambient temperature of full-scale RC beams strengthened with CFRP laminates according to the externally bonded reinforcement (EBR) and near surface mounted (NSM) techniques, in both cases fully or partially bonded (the latter simulating the cable). The FE models were calibrated with results of 4-point bending tests on small-scale beams and then extended for different beam geometries, with spans (L) varying from 2 m to 5 m, in which the influence of the CFRP bonded length (lb) and the loading type (point or uniformly distributed) on the strength reduction was

  2. Numerical study of the role of mortar joints in the bond behavior of FRP-strengthened masonry

    OpenAIRE

    Ghiassi, Bahman; Oliveira, Daniel V.; Lourenço, Paulo B.; Marcari, Giancarlo

    2013-01-01

    The performance of the interface between FRP and masonry is one of the key factors affecting the behavior of strengthened masonry elements. Therefore, a sound understanding of the interface behavior is crucial at the design stage. In this paper, the effect of mortar joints in the bond behavior of FRP-strengthened masonry prisms is investigated through numerical modeling. The numerical simulation is performed by adopting a nonlinear three-dimensional micro-modeling approach. Different smeared ...

  3. A damage model to predict the durability of bonded assemblies. Part I : Debonding behavior of FRP strengthened concrete structures

    OpenAIRE

    Benzarti, Karim; Freddi, Francesco; Fremond, Michel

    2011-01-01

    Presented in this paper is a coupled damage model to predict the durability of concrete elements strengthened by external bonding of fiber reinforced polymer (FRP) plates. Both the concrete, the strengthening FRP and the glue are modeled as damageable materials. The damage model is developed within the framework of the principle of virtual power. The adopted power of the internal forces depends on the damage velocity and on its gradient to take into account local interactions. An interaction ...

  4. Evaluation of feasibility of tungsten/oxide dispersion strengthened steel bonding with vanadium insert

    International Nuclear Information System (INIS)

    A diffusion bonding (DB) technique to reduce thermal expansion coefficient mismatch between tungsten (W) and oxide dispersion strengthened ferritic steel (ODS-FS) was developed by applying a vanadium (V) alloy as an insert material. In order to suppress σ phase precipitation at the interface, DB of ODS-FS and V-4Cr-4Ti was carried out by introducing a Ti insert as a diffusion barrier between V-4Cr-4Ti and ODS-FS, and examined feasibility of W/V/Ti/ODS-FS joint for application to fusion reactor components by comparing the three-point bending strength and microstructure between the joints with and without a Ti diffusion barrier layer. It is shown that the fracture strength of the joint without a Ti insert was decreased by 25% after aging at 700°C for 100 h, but that with a Ti insert shows no change after the aging treatment up to 1000 h. The result indicates that the introduction of a Ti insert leads to the prevention of the formation of σ phase during aging and resultant control of the degradation of the bonding strength. (author)

  5. Interfacial stresses in damaged RC beams strengthened with externally bonded CFRP plate

    Energy Technology Data Exchange (ETDEWEB)

    Benrahou, K.H. [Laboratoire des Materiaux et Hydrologie, Universite de Sidi Bel Abbes, BP 89 Cite Ben M' hidi 22000 Sidi Bel Abbes (Algeria); Adda bedia, E.A. [Laboratoire des Materiaux et Hydrologie, Universite de Sidi Bel Abbes, BP 89 Cite Ben M' hidi 22000 Sidi Bel Abbes (Algeria)]. E-mail: addabed@yahoo.com; Benyoucef, S. [Laboratoire des Materiaux et Hydrologie, Universite de Sidi Bel Abbes, BP 89 Cite Ben M' hidi 22000 Sidi Bel Abbes (Algeria); Tounsi, A. [Laboratoire des Materiaux et Hydrologie, Universite de Sidi Bel Abbes, BP 89 Cite Ben M' hidi 22000 Sidi Bel Abbes (Algeria); Benguediab, M. [Laboratoire des Materiaux et Hydrologie, Universite de Sidi Bel Abbes, BP 89 Cite Ben M' hidi 22000 Sidi Bel Abbes (Algeria)

    2006-09-25

    A theoretical method to predict the interfacial stresses in the adhesive layer of damaged reinforced concrete beams strengthened with externally bonded carbon fiber-reinforced polymer (CFRP) plate is presented. The adopted model is developed including the adherend shear deformations by assuming a linear shear stress through the depth of the RC beam [A. Tounsi, Int. J. Solids Struct., in press], while all existing solutions neglect this effect [e.g. S. Benyoucef, A. Tounsi, S.A. Meftah, E.A. Adda Bedia, Compos. Interfaces, in press; S.T. Smith, J.G. Teng, Eng. Struct. 23 (7) (2001) 857-871; T.M. Roberts, Struct. Eng. 67 (12) (1989) 229-233; A. Tounsi, S. Benyoucef, Int. J. Adhes. Adhes., in press; T. Stratford, J. Cadei, Construct. Building Mater. 20 (2006) 34-35]. In addition, in the present study the anisotropic damage model is adopted to describe the damage of the RC beams. It is shown that the damage has a significant effect on the interfacial stresses in FRP-damaged RC beam.

  6. Interfacial stresses in damaged RC beams strengthened with externally bonded CFRP plate

    International Nuclear Information System (INIS)

    A theoretical method to predict the interfacial stresses in the adhesive layer of damaged reinforced concrete beams strengthened with externally bonded carbon fiber-reinforced polymer (CFRP) plate is presented. The adopted model is developed including the adherend shear deformations by assuming a linear shear stress through the depth of the RC beam [A. Tounsi, Int. J. Solids Struct., in press], while all existing solutions neglect this effect [e.g. S. Benyoucef, A. Tounsi, S.A. Meftah, E.A. Adda Bedia, Compos. Interfaces, in press; S.T. Smith, J.G. Teng, Eng. Struct. 23 (7) (2001) 857-871; T.M. Roberts, Struct. Eng. 67 (12) (1989) 229-233; A. Tounsi, S. Benyoucef, Int. J. Adhes. Adhes., in press; T. Stratford, J. Cadei, Construct. Building Mater. 20 (2006) 34-35]. In addition, in the present study the anisotropic damage model is adopted to describe the damage of the RC beams. It is shown that the damage has a significant effect on the interfacial stresses in FRP-damaged RC beam

  7. Overview Shear Strengthening of RC Beams with Externally Bonded FRP Composites

    Science.gov (United States)

    Alzoubi, Feras; Zhengliang, Li

    Shear strengthening is required when an RC beam is found deficient in shear, or when its shear capacity falls below its flexural capacity after flexural strengthening. This study presents a state-of-the-art review of existing research on this topic. The research programs conducted to investigate the shear performance and to evaluate the shear capacity of the strengthened beams are reviewed in this paper by details. The research is a good reference for all engineers and researchers in fields of shear strengthening and repair RC beams in building and bridges.

  8. Strengthening a prestressed concrete slab by epoxy-bonded FRP composites and SFRC overlayer

    OpenAIRE

    Barros, Joaquim A. O.; Sena-Cruz, José

    2001-01-01

    Laminates of carbon fibre reinforced polymer (CFRP), layer of steel fibre reinforced concrete (SFRC) and the simultaneous use of CFRP laminates and SFRC overlayer were the strengthening strategies analysed for increasing the load bearing capacity of a concrete slab. A numerical model developed for simulating these strengthening techniques is described and the results obtained are analysed.

  9. Treatment of Progressive First Metatarsophalangeal Hallux Valgus Deformity: A Biomechanically Based Muscle-Strengthening Approach.

    Science.gov (United States)

    Glasoe, Ward M

    2016-07-01

    Synopsis Hallux valgus is a progressive deformity of the first metatarsophalangeal joint that changes the anatomy and biomechanics of the foot. To date, surgery is the only treatment to correct this deformity, though the recurrence rate is as high as 15%. This clinical commentary provides instruction in a strengthening approach for treatment of hallux valgus deformity, by addressing the moment actions of 5 muscles identified as having the ability to counter the hallux valgus process. Unlike surgery, muscle strengthening does not correct the deformity, but, instead, reduces the pain and associated gait impairments that affect the mobility of people who live with the disorder. This review is organized in 4 parts. Part 1 defines the terms of foot motion and posture. Part 2 details the anatomy and biomechanics, and describes how the foot is changed with deformity. Part 3 details the muscles targeted for strengthening; the intrinsics being the abductor hallucis, adductor hallucis, and the flexor hallucis brevis; the extrinsics being the tibialis posterior and fibularis longus. Part 4 instructs the exercise and reviews the related literature. Instructions are given for the short-foot, the toe-spread-out, and the heel-raise exercises. The routine may be performed by almost anyone at home and may be adopted into physical therapist practice, with intent to strengthen the foot muscles as an adjunct to almost any protocol of care, but especially for the treatment of hallux valgus deformity. J Orthop Sports Phys Ther 2016;46(7):596-605. Epub 6 Jun 2016. doi:10.2519/jospt.2016.6704. PMID:27266887

  10. Strengthening the University/School Bond and Ensuring the Success of Teacher-Candidates

    Science.gov (United States)

    North, Cheryl; Singer, Jonathan; Neugebauer, William J.

    2014-01-01

    In order to strengthen communication between UMBC and its Professional Development School (PDS) network, we implemented an interview process prior to internship that required all students to interview with a school in the PDS network. This article outlines the interview process including the questions, assessment, and logistical issues. Further it…

  11. Progressive Failure Analysis on the Single Lap Bonded Joints

    Directory of Open Access Journals (Sweden)

    Kadir TURAN

    2010-03-01

    Full Text Available In this study, the failure analysis on the single lap bonded joint, which is used for joined two composite plates each other with adhesive, is investigated experimentally and numerically. In the joint, the epoxy resin is used for adhesive and the four layered carbon fiber reinforced epoxy matrix resin composite plates are used for adherent. Numerical study is performed in the ANSYS software which is used finite element method for solution. For obtained numerical failure loads, the progressive failure analysis is used with material property degradation rules. In the failure analysis the Hashin Failure Criterion is used for composite plates and the Maximum Principal Stress failure criterion is used for adhesive. The effects of the adhesive thickness overlap lengths and plate weight on the joint strength is investigated with numerically. As a result it is seen that the failure loads is affected the bond face area. The results are presented with graphs and tables.

  12. DUCTILITY BEHAVIOR FIBER REINFORCED CONCRETE BEAMS STRENGTHENED WITH EXTERNALLY BONDED GLASS FIBER REINFORCED POLYMER LAMINATES

    OpenAIRE

    Mariappan Mahalingam; Ragunath Pulipakka Narashima Rao; Suguna Kannan

    2013-01-01

    The study presents the results of an experimental investigation conducted on Steel Fiber Reinforced Concrete (SFRC) beams with externally bonded Glass Fiber Reinforced Polymer (GFRP) laminates with a view to study their strength and ductility. A total of ten beams, 150Ã250 mm in cross-section were tested in the laboratory over an effective span of 2800 mm. Three fiber reinforced concrete beams were used as reference beams. Six fiber reinforced concrete beams were provided with externally bond...

  13. Effect of Shear Resistance on Flexural Debonding Load-Carrying Capacity of RC Beams Strengthened with Externally Bonded FRP Composites

    Directory of Open Access Journals (Sweden)

    Guibing Li

    2014-05-01

    Full Text Available Debonding failure is the main failure mode in flexurally strengthened reinforced concrete beams by externally bonded or near surface mounted fibre reinforced polymer (FRP composites. It is believed that FRP debonding will be initiated if the shear stress on the concrete-FRP interface reaches the tensile strength of concrete. However, it was found through experimental and analytical studies that the debonding mechanism of FRP composites has the potential of shear failure in combination with debonding failure. Moreover, the shear failure probably influences the debonding failure. Presently, there are very little experimental and analytical studies to investigate the influence of shear resistance of reinforced concrete (RC beam on FRP debonding failure. The current study investigates and analyzes the effect of shear resistance on FRP debonding failure based on test results. The analytical results show that the shear resistance of RC beam has a great effect on flexural debonding load-carrying capacity of FRP-strengthened RC beam. The influence of shear resistance on flexural debonding load-carrying capacity must be fully considered in flexural strengthening design of RC beams.

  14. Hydrogen Bonding: Between Strengthening the Crystal Packing and Improving Solubility of Three Haloperidol Derivatives

    Directory of Open Access Journals (Sweden)

    Hardeep Saluja

    2016-06-01

    Full Text Available The purpose of this study is to confirm the impact of polar functional groups on inter and intra-molecular hydrogen bonding in haloperidol (HP and droperidol (DP and, hence, their effects on dissolution using a new approach. To confirm our theory, a new molecule: deshydroxy-haloperidol (DHP was designed and its synthesis was requested from a contract laboratory. The molecule was then studied and compared to DP and HP. Unlike DHP, both the HP and DP molecules have hydrogen donor groups, therefore, DHP was used to confirm the relative effects of the hydrogen donor group on solubility and crystal packing. The solid dispersions of the three structurally related molecules: HP, DP, and DHP were prepared using PVPK30, and characterized using XRPD and IR. A comparative dissolution study was carried out in aqueous medium. The absence of a hydrogen bonding donor group in DHP resulted in an unexpected increase in its aqueous solubility and dissolution rate from solid dispersion, which is attributed to weaker crystal pack. The increased dissolution rate of HP and DP from solid dispersions is attributed to drug-polymer hydrogen bonding that interferes with the drug-drug intermolecular hydrogen bonding and provides thermodynamic stability of the dispersed drug molecules. The drug-drug intermolecular hydrogen bond is the driving force for precipitation and crystal packing.

  15. DUCTILITY BEHAVIOR FIBER REINFORCED CONCRETE BEAMS STRENGTHENED WITH EXTERNALLY BONDED GLASS FIBER REINFORCED POLYMER LAMINATES

    Directory of Open Access Journals (Sweden)

    Mariappan Mahalingam

    2013-01-01

    Full Text Available The study presents the results of an experimental investigation conducted on Steel Fiber Reinforced Concrete (SFRC beams with externally bonded Glass Fiber Reinforced Polymer (GFRP laminates with a view to study their strength and ductility. A total of ten beams, 150×250 mm in cross-section were tested in the laboratory over an effective span of 2800 mm. Three fiber reinforced concrete beams were used as reference beams. Six fiber reinforced concrete beams were provided with externally bonded GFRP laminates. One concrete beam was left virgin without any fiber reinforcement and external GFRP laminates. All the beams were tested until failure. The variables considered included volume fraction of fiber reinforcement and stiffness of GFRP laminates. The static responses of all the beams were evaluated in terms of strength, stiffness and ductility. The test results show that the beams provided with externally bonded GFRP laminates exhibit improved performance over the beams with internal fiber reinforcement.

  16. C-Anchor for Strengthening the Connection between Adhesively Bonded Laminates and Concrete Substrates

    Directory of Open Access Journals (Sweden)

    Ghani Razaqpur

    2015-11-01

    Full Text Available A new carbon fiber reinforced polymer (CFRP anchor is developed and tested to delay debonding in reinforced concrete (RC beams externally strengthened with FRP laminate/sheet. The C-shape anchor is made from a commercially available CFRP grid. The anchors legs are 95 mm long while the spacing between the legs is adjustable, depending on FRP laminate and beam widths. Nine full scale RC beams, 3.0 m long, 250 mm wide and 400 mm deep, were strengthened with CFRP laminate/sheet, with and without the C-anchor. The main test parameters were the type and amount of FRP laminate and the presence/absence of the anchor. Test results showed that beams with the anchor had generally 5%–10% higher debonding and failure load, and they reached higher deflection at failure than the companion beams without anchors. Although complete separation of the FRP laminate from the concrete was not observed in any of the beams with anchors, there was noticeable slip at failure at one end of the laminate. A significant outcome of the study is that anchors are effective in limiting the extent of debonding along the laminate, thus contributing to the flexural stiffness of the beam by reducing the extent of cracking and limiting the crack width along the beam. Finally, the anchor allowed the FRP to reach or exceed its theoretically allowable strain computed based on the American Concrete Institute (ACI Committee 440 recommendation while in none of the beams without anchors, the FRP reached its theoretically allowable strain.

  17. Adhesive Characterization and Progressive Damage Analysis of Bonded Composite Joints

    Science.gov (United States)

    Girolamo, Donato; Davila, Carlos G.; Leone, Frank A.; Lin, Shih-Yung

    2014-01-01

    The results of an experimental/numerical campaign aimed to develop progressive damage analysis (PDA) tools for predicting the strength of a composite bonded joint under tensile loads are presented. The PDA is based on continuum damage mechanics (CDM) to account for intralaminar damage, and cohesive laws to account for interlaminar and adhesive damage. The adhesive response is characterized using standard fracture specimens and digital image correlation (DIC). The displacement fields measured by DIC are used to calculate the J-integrals, from which the associated cohesive laws of the structural adhesive can be derived. A finite element model of a sandwich conventional splice joint (CSJ) under tensile loads was developed. The simulations indicate that the model is capable of predicting the interactions of damage modes that lead to the failure of the joint.

  18. A theoretical study on 2‧-deoxyguanosine and its mono-hydration: Intermolecular hydrogen bonding weakening induces the fluorescence strengthening

    Science.gov (United States)

    Liu, Yufang; Yang, Yonggang; Jiang, Kai; Shi, Deheng; Sun, Jinfeng

    2012-03-01

    The time-dependent density functional theory (TDDFT) method has been applied to investigate the excited states of 2'-deoxyguanosine (2'-dG) and its monohydrated complex (2'-dG-W1). The intramolecular hydrogen bonding N3⋯H2-O2 of the keto conformer is weakened in the S1 state, while that of the enol conformers is strengthened. The two intermolecular hydrogen bondings of 2'-dG-W1 are weakened in the S1 state, while N3⋯H2-O2 gets more strengthened. Moreover, the fluorescence of 2'-dG-W1 is shifted to higher frequencies compared with that of monomer 2'-deoxyguanosine. Therefore, it is concluded that the weakening of intermolecular hydrogen bonding in the S1 state induces fluorescence strengthening of 2'-deoxyguanosine.

  19. Epoxy Enhanced by Recycled Milled Carbon Fibres in Adhesively-Bonded CFRP for Structural Strengthening

    Directory of Open Access Journals (Sweden)

    Chao Wu

    2013-12-01

    Full Text Available This paper investigates the mechanical performance and electrical resistivity of a structural adhesive epoxy enhanced using milled carbon fibre (MCF as well as the bond performance of carbon fibre reinforced polymers (CFRP and steel adhesively bonded joints using the enhanced epoxy. The epoxy was enhanced using such MCFs with different weight ratios of 1.5%, 3% and 5%. Tensile experiments were performed on the original and enhanced epoxy specimens according to ASTM D638. More ductile process failure was found for the epoxy after modification and significant improvements of E-modulus and tensile strength were evidenced when the MCF weight ratio was larger than 1.5%. Scanning electron microscopy (SEM revealed that the failure mechanism of short MCFs pulled out from the epoxy matrix contributed to the enhancement of the mechanical performance of the epoxy. The electrical resistivity of the epoxy with MCF weight ratio of 5% was reduced by at least four orders of magnitude compared to the original epoxy, due to the conductive network formed by MCFs. Steel/CFRP double strap joints (with either CFRP sheets or CFRP laminates were prepared using the enhanced epoxy and then tested in tension, however no obvious increase in joint stiffness or strength was observed.

  20. Molecular orbitual studies of the bonding in heavy element organometallics: Progress report

    International Nuclear Information System (INIS)

    Progress to date is described in 2 major areas: (1) Tris(cyclopentadienyl) actinide complexes. We have made considerable progress in our studies of the electronic structure of organoactinide compounds containing three cyclopentadienyl ligands: investigations of the ''base-free'' compounds Cp3An, and investigations of the interaction of Cp3An compounds with a fourth ligand, L. (2) Actinide-containing molecules with metal-metal bonds, actinide-actinide bonds, and actinide-transition metal bonds

  1. Effectively Exerting the Reinforcement of Dopamine Reduced Graphene Oxide on Epoxy-Based Composites via Strengthened Interfacial Bonding.

    Science.gov (United States)

    Li, Wenbin; Shang, Tinghua; Yang, Wengang; Yang, Huichuan; Lin, Song; Jia, Xiaolong; Cai, Qing; Yang, Xiaoping

    2016-05-25

    The effects of dopamine reduced graphene oxide (pDop-rGO) on the curing activity and mechanical properties of epoxy-based composites were evaluated. Taking advantage of self-polymerization of mussel-inspired dopamine, pDop-rGO was prepared through simultaneous functionalization and reduction of graphene oxide (GO) via polydopamine coating. Benefiting from the universal binding ability of polydopamine, good dispersion of pDop-rGO in epoxy matrix was able to be achieved as the content of pDop-rGO being below 0.2 wt %. Curing kinetics of epoxy composites with pDop-rGO were systematically studied by nonisothermal differential scanning calorimetry (DSC). Compared to the systems of neat epoxy or epoxy composites containing GO, epoxy composites loaded with pDop-rGO showed lower activation energy (Eα) over the range of cure (α). It revealed that the amino-bearing pDop-rGO was able to react with epoxy matrix and enhance the curing reactions as an amine-type curing agent. The nature of the interactions at GO-epoxy interface was further evaluated by Raman spectroscopy, confirming the occurrence of chemical bonding. The strengthened interfacial adhesion between pDop-rGO and epoxy matrix thus enhanced the effective stress transfer in the composites. Accordingly, the tensile and flexural properties of EP/pDop-rGO composites were enhanced due to both the well dispersion and strong interfacial bonding of pDop-rGO in epoxy matrix. PMID:27159233

  2. Strengthening Mechanisms and Electrochemical Behavior of Ultrafine-Grained Commercial Pure Copper Fabricated by Accumulative Roll Bonding

    Science.gov (United States)

    Imantalab, O.; Fattah-Alhosseini, A.; Mazaheri, Y.; Keshavarz, M. K.

    2016-07-01

    In this study, the four-cycle accumulative roll bonding (ARB) process at room temperature was successfully used for grain refining in commercial pure copper. Atomic force microscopy (AFM) images revealed that the average grain size reduced from about 26 µm in the unprocessed material to about 180 nm after four cycles of ARB. Also, transmission electron microscopy image indicated that the average grain size reached to 200 nm after four cycles. The yield strength of the ultrafine-grained pure copper after fourth cycle (360 MPa) was about 400 pct higher than that of the annealed unprocessed sample (70 MPa). The contribution of dislocations in strengthening of the pure copper decreased from ~30 to ~3 pct whit increasing the number of ARB cycles from 1 to 4. Scanning electron microscopy micrographs of fractured surfaces of the tensile test specimens revealed that ductile fracture of annealed sample with deep equiaxed dimples replaced by shear ductile rupture with shallow and small elongated dimples in ARB-processed samples. Moreover, electrochemical impedance spectroscopy and Mott-Schottky analysis showed that the electrochemical behavior improved by increasing the number of ARB cycle.

  3. Recent progress in hydrogen-rich materials from the perspective of bonding flexibility of hydrogen

    International Nuclear Information System (INIS)

    The bonding flexibility of hydrogen is a source of various interesting functionalities in hydrides. Here, we illustrate the benefits of this flexibility through several selected examples of recent progress in the development of hydrogen storage materials. From the viewpoint of electronegativity, we discuss the diverse cohesion and materials science underlying the bonding flexibility of hydrogen in hydrides

  4. Quasi-plane-hypothesis of strain coordination for RC beams seismically strengthened with externally-bonded or near-surface mounted fiber reinforced plastic

    Science.gov (United States)

    Ren, Zhenhua; Zeng, Xiantao; Liu, Hanlong; Zhou, Fengjun

    2013-03-01

    The application of fiber reinforced plastic (FRP), including carbon FRP and glass FRP, for structural repair and strengthening has grown due to their numerous advantages over conventional materials such as externally bonded reinforcement (EBR) and near-surface mounted (NSM) strengthening techniques. This paper summarizes the results from 21 reinforced concrete beams strengthened with different methods, including externally-bonded and near-surface mounted FRP, to study the strain coordination of the FRP and steel rebar of the RC beam. Since there is relative slipping between the RC beam and the FRP, the strain of the FRP and steel rebar of the RC beam satisfy the quasi-plane-hypothesis; that is, the strain of the longitudinal fiber that parallels the neutral axis of the plated beam within the scope of the effective height ( h 0) of the cross section is in direct proportion to the distance from the fiber to the neutral axis. The strain of the FRP and steel rebar satisfies the equation: ɛ FRP= βɛ steel, and the value of β is equal to 1.1-1.3 according to the test results.

  5. TDDFT study on the excited-state proton transfer of 8-hydroxyquinoline: Key role of the excited-state hydrogen-bond strengthening

    Science.gov (United States)

    Lan, Sheng-Cheng; Liu, Yu-Hui

    2015-03-01

    Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations have been employed to study the excited-state intramolecular proton transfer (ESIPT) reaction of 8-hydroxyquinoline (8HQ). Infrared spectra of 8HQ in both the ground and the lowest singlet excited states have been calculated, revealing a red-shift of the hydroxyl group (-OH) stretching band in the excited state. Hence, the intramolecular hydrogen bond (O-H···N) in 8HQ would be significantly strengthened upon photo-excitation to the S1 state. As the intramolecular proton-transfer reaction occurs through hydrogen bonding, the ESIPT reaction of 8HQ is effectively facilitated by strengthening of the electronic excited-state hydrogen bond (O-H···N). As a result, the intramolecular proton-transfer reaction would occur on an ultrafast timescale with a negligible barrier in the calculated potential energy curve for the ESIPT reaction. Therefore, although the intramolecular proton-transfer reaction is not favorable in the ground state, the ESIPT process is feasible in the excited state. Finally, we have identified that radiationless deactivation via internal conversion (IC) becomes the main dissipative channel for 8HQ by analyzing the energy gaps between the S1 and S0 states for the enol and keto forms.

  6. Strain coordination of quasi-plane-hypothesis for reinforced concrete beam strengthened by epoxy-bonded glass fiber reinforced plastic plate

    Institute of Scientific and Technical Information of China (English)

    ZENG Xian-tao; DING Ya-hong; WANG Xing-guo

    2006-01-01

    The testing of thirteen reinforced concrete (RC) beams strengthened by epoxy-bonded glass fiber reinforced plastic plate (GFRP) shows that the RC beam and the GFRP plate with epoxy bonding on it can work fairly well in coordination to each other. But there is relative slipping between RC beam and GFRP plate. And the strain of GFRP and steel rebar of RC beam satisfies the quasi-plane-hypothesis, that is, the strain of longitudinal fiber that parallels to the neutral axis of plated beam within the scope of effective height (h0) of the cross section is in direct proportion to the distance from the fiber to the neutral axis. The strain of GFRP and steel rebar satisfies the equation: εCFRP = Kεsteel.

  7. 粘贴竹片加固混凝土梁的试验研究%Strengthening RC Beams with Externally Bonded Bamboo Strips

    Institute of Scientific and Technical Information of China (English)

    朱雷; 许清风; 陈建飞

    2012-01-01

    竹材是一种可再生的低碳环保材料,具有抗拉强度高、稳定性好等优点.混凝土梁老化损伤或使用荷载增加均可能导致受弯承载力不能满足要求,影响结构的正常安全使用.介绍5根RC梁粘贴竹片加固的对比试验研究,其中2根为对比试件,3根为分别粘贴1层、2层和3层的竹片加固试件.研究结果表明,粘贴竹片加固RC梁的极限承载力提高22%~25%,平均提高24%;粘贴竹片加固RC梁的初始弯曲刚度提高33%~49%,平均提高39%;粘贴竹片加固RC梁在相同荷载下弯曲裂缝的裂缝宽度明显小于对比试件.粘贴竹片加固RC梁是一种低碳高效的加固技术,值得进一步深入研究.%Bamboo is a renewable, low-carbon and environmentally-friendly natural material with high tensile strength and good stability. Many RC beams need to be strengthened due to either accumulative damage or an increase of loading. This paper presents an experimental study in which 5 RC beams were tested, including two unstrengthened RC beams used to compare, three RC beams strengthened with one, two and three layers of 5mm bamboo strips, respectively. The test results show that the ultimate flexural strength of RC beams was increased by 22% ~25% with an average of 24% after strengthened by a few externally bonded small bamboo strips. The flexural stiffness of the strengthened beams was also significantly increased by 33% ~49% with an average of 39%. The flexural crack width of the strengthened RC beams was smaller than that of the control beams at the same loading levels. The tests confirm that strengthening RC beams with bamboo strips is a promising effective and low-carbon technique worth further research.

  8. Building relationships with physicians. Internal marketing efforts help strengthen organizational bonds at a rural health care clinic.

    Science.gov (United States)

    Peltier, J W; Boyt, T; Westfall, J E

    1997-01-01

    Physician turnover is costly for health care organizations, especially for rural organizations. One approach management can take to reduce turnover is to promote physician loyalty by treating them as an important customer segment. The authors develop an information--oriented framework for generating physician loyalty and illustrate how this framework has helped to eliminate physician turnover at a rural health care clinic. Rural health care organizations must develop a more internal marketing orientation in their approach to establishing strong relationship bonds with physicians. PMID:10173904

  9. Scaling of the critical free length for progressive unfolding of self-bonded graphene

    Energy Technology Data Exchange (ETDEWEB)

    Kwan, Kenny; Cranford, Steven W., E-mail: s.cranford@neu.edu [Laboratory of Nanotechnology in Civil Engineering (NICE), Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, Massachusetts 02115 (United States)

    2014-05-19

    Like filled pasta, rolled or folded graphene can form a large nanocapsule surrounding a hollow interior. Use as a molecular carrier, however, requires understanding of the opening of such vessels. Here, we investigate a monolayer sheet of graphene as a theoretical trial platform for such a nanocapsule. The graphene is bonded to itself via aligned disulfide (S-S) bonds. Through theoretical analysis and atomistic modeling, we probe the critical nonbonded length (free length, L{sub crit}) that induces fracture-like progressive unfolding as a function of folding radius (R{sub i}). We show a clear linear scaling relationship between the length and radius, which can be used to determine the necessary bond density to predict mechanical opening/closing. However, stochastic dissipated energy limits any exact elastic formulation, and the required energy far exceeds the dissociation energy of the S-S bond. We account for the necessary dissipated kinetic energy through a simple scaling factor (Ω), which agrees well with computational results.

  10. FRP : Strengthened RC Structures

    Science.gov (United States)

    Teng, J. G.; Chen, J. F.; Smith, S. T.; Lam, L.

    2002-01-01

    The strengthening of reinforced concrete (RC) structures using advanced fibre-reinforced polymer (FRP) composites, and in particular the behaviour of FRP-strengthened RC structures is a topic which has become very popular in recent years. This popularity has arisen due to the need to maintain and upgrade essential infrastructure in all parts of the world, combined with the well-known advantages of FRP composites, such as good corrosion resistance and ease for site handling due to their light weight. The continuous reduction in the material cost of FRP composites has also contributed to their popularity. While a great amount of research now exists in the published literature on this topic, it is scattered in various journals and conference proceedings. This book therefore provides the first ever comprehensive, state-of-the-art summary of the existing research on FRP strengthening of RC structures, with the emphasis being on structural behaviour and strength models. The main topics covered include: Bond behaviour Flexural and shear strengthening of beams Column strengthening Flexural strengthening of slabs. For each area, the methods of strengthening are discussed, followed by a description of behaviour and failure modes and then the presentation of rational design recommendations, for direct use in practical design of FRP strengthening measures. Researchers, practicing engineers, code writers and postgraduate students in structural engineering and construction materials, as well as consulting firms, government departments, professional bodies, contracting firms and FRP material suppliers will find this an invaluable resource.

  11. Cohesive Laws and Progressive Damage Analysis of Composite Bonded Joints, a Combined Numerical/Experimental Approach

    Science.gov (United States)

    Girolamo, Donato; Davila, Carlos G.; Leone, Frank A.; Lin, Shih-Yung

    2015-01-01

    The results of an experimental/numerical campaign aimed to develop progressive damage analysis (PDA) tools for predicting the strength of a composite bonded joint under tensile loads are presented. The PDA is based on continuum damage mechanics (CDM) to account for intralaminar damage, and cohesive laws to account for interlaminar and adhesive damage. The adhesive response is characterized using standard fracture specimens and digital image correlation (DIC). The displacement fields measured by DIC are used to calculate the J-integrals, from which the associated cohesive laws of the structural adhesive can be derived. A finite element model of a sandwich conventional splice joint (CSJ) under tensile loads was developed. The simulations, in agreement with experimental tests, indicate that the model is capable of predicting the interactions of damage modes that lead to the failure of the joint.

  12. Modeling Progressive Failure of Bonded Joints Using a Single Joint Finite Element

    Science.gov (United States)

    Stapleton, Scott E.; Waas, Anthony M.; Bednarcyk, Brett A.

    2010-01-01

    Enhanced finite elements are elements with an embedded analytical solution which can capture detailed local fields, enabling more efficient, mesh-independent finite element analysis. In the present study, an enhanced finite element is applied to generate a general framework capable of modeling an array of joint types. The joint field equations are derived using the principle of minimum potential energy, and the resulting solutions for the displacement fields are used to generate shape functions and a stiffness matrix for a single joint finite element. This single finite element thus captures the detailed stress and strain fields within the bonded joint, but it can function within a broader structural finite element model. The costs associated with a fine mesh of the joint can thus be avoided while still obtaining a detailed solution for the joint. Additionally, the capability to model non-linear adhesive constitutive behavior has been included within the method, and progressive failure of the adhesive can be modeled by using a strain-based failure criteria and re-sizing the joint as the adhesive fails. Results of the model compare favorably with experimental and finite element results.

  13. Strengthening non-state climate action: a progress assessment of commitments launched at the 2014 UN Climate Summit

    OpenAIRE

    Chan, Sander; Falkner, Robert; van Asselt, Harro; Goldberg, Matthew

    2015-01-01

    This report provides the first progress assessment of climate actions launched at the 2014 UN Climate Summit in New York. It considers the distribution and performance of climate actions along multiple dimensions that are relevant to both mitigation and adaptation. While it is too early for a conclusive assessment of the effectiveness of climate actions, this study makes a first and indispensable step toward such an assessment. Initial findings are encouraging. One year after their launch, mo...

  14. Study on flexural behavior of pre-cracked RC beams strengthened with externally bonded CFS%CFS加固开裂混凝土受弯构件的抗弯性能研究

    Institute of Scientific and Technical Information of China (English)

    廖娟; 金坚; 徐兴

    2009-01-01

    The flexural behavior of pre-cracked RC beams strengthened with externally bonded CFS,which loads have been removed before strengthening,is studied.The effect of the loads which have been removed and plies of CFS are investigated.A series of 17 RC beams(including 2 contrast beams and 15 retrofitted with CFS)were tested to investigate the effect of preload and number of plies of CFS.The study indicated that the ultimate capacity and the stiffness of strengthened beams are increased compared with contrast beam except that the value of preload is under a certain degree.The upper limit of preload was found out and the number of CFS plies was also suggested.%针对加固时已卸载的混凝土受弯构件开展碳纤维布(CFS)加固性能研究.共进行了17根混凝土梁的试验,包括2根对比梁和15根CFS抗弯加固梁.研究了开裂程度、CFS加固层数对加固构件的破坏形态、承载力等力学性能的影响.总结了CFS加固开裂混凝土受弯构件时曾加荷载的上限范围,给出了CFS加固合理用量的建议.

  15. 基于二次受力的粘钢加固RC梁位移延性分析%Displacement Ductility Analysis of RC Beam Strengthened by Bonded Steel Plates Based on the Secondary Stress

    Institute of Scientific and Technical Information of China (English)

    罗臻; 葛新广

    2009-01-01

    针对粘贴钢板加固RC梁的二次受力特性,在混凝土结构设计规范中抗弯设计计算的基本原理基础上,通过对粘贴钢板加固RC梁的受力分析,提出了其位移延性的计算方法,并讨论了其影响因素.分析结果表明,后粘钢板用量及其卸载百分比是影响RC梁加固后延性的主要因素.%Aiming at secondary stress characteristics of the RC beam strengthened by bonded steel plates,based on the fundamental theory of flexural design calculation of code for design of concrete structures,through the stress analysis of the RC beam strengthened by bonded steel plates, this paper presented a calculation method of its displacement ductility. And the influencing factors on it were discussed. The results show that the quantity of steel plate and its unload percentage are the most important factors influencing the ductility.

  16. Research Progress on the Nano Ceramic Bond (cBN)Grinding Wheel%纳米陶瓷结合剂 cBN 砂轮的研究进展

    Institute of Scientific and Technical Information of China (English)

    刘瑞平; 苏伟明

    2014-01-01

    In this artical,the performance characteristics,strengthening and toughening mechanism of the nano ceramic bond grinding wheel,as well as its research progress have been comprehensively discussed.The existing problems and solutions of the nano ceramic bond grinding wheel in its manufacturing process have also been discussed.It is indicated that the current existing contradiction between low melting point and high strength for the ceramic bond can be solved by the application of nano ceramic bond .What's more,it has a great significance for broadening the scope of application of cBN grinding wheels and meeting the requirement of ultra-high speed grinding technology.%文章综合论述了纳米陶瓷结合剂的性能特点、增强增韧机理以及研究进展,并探讨了纳米陶瓷结合剂 cBN 砂轮制备过程中存在的问题及对策,指出纳米陶瓷结合剂不仅可以解决目前陶瓷结合剂低熔点与高强度之间的矛盾,而且对于拓宽 cBN 砂轮的应用范围、适应超高速磨削技术具有十分重要的意义。

  17. 外粘 AFRP 布加固 RC梁冲击试验分析%Impact Damage Test of RC Beams Strengthened with Externally Bonded AFRP Sheet

    Institute of Scientific and Technical Information of China (English)

    王兴国; 朱坤佳; 栗橋祐介

    2015-01-01

    Experimental tests were carried out respectively on the performance of non‐strengthened RC beams and RC beams strengthened with externally bonded (EB) aramid fiber reinforced polymer (AFRP) sheet under two loading methods ,the monotonically static and falling‐weight impact loading methods ,to analyze the failure process of RC beams and strain curve of EB AFRP sheet during test loading .Failure patterns and crack devel‐opment of the test beams under different impact height were compared to conclude the correlation between im‐pact height and final failure patterns of the beams .Test results showed that ,under the static loading ,the non‐strengthened beams failed as a result of steel bar yielding while the strengthened beams failed as a result of EB AFRP sheet debonding .Under the falling‐weight impact loading ,the non‐strengthened beams were destroyed as a result of steel bar yielding caused by impact damage ,while the strengthened beams were destroyed as a re‐sult of either EB AFRP sheet debonding or abrupt tension fracture .%通过单调静力和重锤冲击两种加载方式,分别对未加固梁和外粘A FRP布加固梁的性能进行试验研究,分析冲击加载时混凝土梁的破坏过程及外粘A FRP布的应变曲线。比较不同冲击高度下梁体的损伤形态和裂缝分布规律,从而得出冲击高度与梁体最终破坏形态的相关性。试验表明:在静力加载条件下,未加固梁是因钢筋屈服而破坏,加固梁是因外粘A FRP布剥离而破坏;在重锤冲击加载条件下,未加固梁是因梁体出现冲击损伤时钢筋屈服而破坏,加固梁是因梁体出现冲击损伤时外粘AFRP布可能发生端部剥离或跨中断裂而破坏。

  18. Simulating progressive social transfers. Gas subsidies and solidarity bonds in Ecuador

    International Nuclear Information System (INIS)

    After two decades of neglect, social expending has become a cornerstone in the current fight against poverty in Ecuador. Ecuador is presently considering the elimination of regressive gas subsidies and the shift of these resources into pro-poor targeted Solidarity Bonds. Great distributive gains are expected from this reform. There are, however, a number of considerations that may prevent this policy shift from obtaining substantial poverty and equality gains. Despite their regressivity, implicit gas subsidies still represent a considerable proportion of total household consumption among poor households. Also, solidarity bonds siphon off a substantial share of their total benefits to middle income groups. This paper estimates the redistributive consequences of policy reforms on gas subsidies and solidarity bonds in Ecuador. A simulation methodology estimates both direct and indirect (labour-driven) distributive effects of four alternative scenarios: (1) total elimination of gas subsidies; (2) selective elimination of gas subsidies among non-poor households; (3) total elimination of gas subsidies and shift of resources to solidarity bonds targeted to the poor; (4) selective elimination of gas subsidies and shift of resources to solidarity bonds targeted to the poor. Estimates confirm that the redistributive gains from these reforms are rather small both for poverty and inequality. Incentives to work following the elimination of subsidies compensate, or even outdo, immediate poverty rises. Also, the elimination of gas subsidies without further expansion of subsidy bonds will unambiguously increase poverty in Ecuador between one and one and a half percent points

  19. FRP侧贴加固钢筋混凝土梁受弯承载力计算与分析%Calculation and Analysis on Flexural Capacity of RC Beam Strengthened with Side-Bonded FRP

    Institute of Scientific and Technical Information of China (English)

    陈绪军; 戴木香; 徐芸

    2011-01-01

    The bending failure modes of and design requirements for Reinforced Concrete(RC) member strengthened with side-bonded Fiber Reinforced Polymer (FRP) are investigated through tests on its flexural behavior. With theoretical method of calculating flexural capacity on the positive section based on the assumption of plane section, a practical calculation method for the flexural strength reinforced with side-bonded FRP is put forward. The calculated values, which are well consistent with the test data, are reliable and can be referential for designers. The study also probed into the values of correction coefficient ηf in Design Code for Strengthening Concrete Structure ( GB 50367-2006) when FRP is bonded on the sides of RC beams rather than on the bottom. When hf/h is a fixed value , the correction coefficient ηf is not a definite value as shown in the design above code, but varies with the parameters of the strengthened RC beams.%根据纤维增强复合材料(Fiber Reinforced Plastics)侧贴加固钢筋混凝土构件受弯性能的试验研究,对受弯破坏形态和设计要求进行了讨论.基于平截面假定的正截面受弯承载力的计算理论,提出了FRP侧贴加固构件的正截面受弯承载力的实用计算方法.计算值与试验值吻合较好,并具有较高的可靠性,可供设计参考.探讨了《混凝土结构加固设计规范》(GB 50367-2006)中由梁底改贴到梁两侧面的FRP截面积修正系数ηf的取值情况:在hf/h为定值时,ηf并不象《混凝土结构加固设计规范》所示为定值,而是随加固梁各参数的变化而变化.

  20. Thickness value of fireproof coating for slabs strengthened with Carbon Fiber Sheet bonded with an inorganic adhesive%无机胶粘贴碳纤维布加固板防火涂层厚度取值

    Institute of Scientific and Technical Information of China (English)

    万夫雄; 郑文忠

    2012-01-01

    For keeping strengthening role of Carbon Fiber Sheet(CFS) bonded with an inorganic adhesive to insure fire safe of structure,thick-typed fireproof coating is needed for protecting CFS.Considering deformation limit of strengthened slabs in fire,temperature on bottom surface of slabs is limited to 415 ℃ by trial calculation of deformation by ABAQUS.By analysis of temperature field of strengthened slabs by ABAQUS,fireproof coating thickness,heat conductivity coefficient and fire duration are the main factors affecting temperature on bottom surface of strengthened slabs,so key factors affecting fireproof coating thickness are heat conductivity coefficient and fire duration.Based on that,in terms of fire endurance and thermal conductivity coefficient of coating,and considering actual construction demand,advised values of fireproof coating thickness are proposed in terms of different type of coating.%为确保火灾下用无机胶粘贴的碳纤维布能正常发挥加固作用,保证结构安全,需要选用一定厚度的厚型防火涂料作为碳纤维布的防火保护层.基于对加固板高温变形限制的考虑,采用ABAQUS对其高温变形进行试算,提出以板底温度415℃作为控制温度计算涂料厚度的原则.采用ABAQUS对加固板温度场进行分析,表明涂料厚度、导热系数以及受火时间是影响板底温度的主要因素,因而决定涂料保护层厚度的关键因素为导热系数和受火时间.在此基础上,按耐火时间和涂料导热系数的不同,分涂料品种并考虑相应构造要求的基础上,给出基于温度控制的防火涂料保护层厚度取值建议.

  1. Polycrystalline strengthening

    DEFF Research Database (Denmark)

    Hansen, Niels

    1985-01-01

    . The strength-grain size relationships can be described in a number of empirical equations relating the yield stress and the flow stress in tension to various structural parameters. A number of such equations are reviewed and their predictive capability is discussed. Structural information of...... importance for the understanding of polycrystalline strengthening is obtained mainly from surface relief patterns and from bulk structures observed by transmission electron microscopy of thin foils. The results obtained by these methods are discussed and correlations are proposed. A number of features...... of the microstructures found, and this structural information is correlated with a number of strength structural equations. Finally, the flow stress of fcc and bcc polycrystalline specimens is related to the occurrence of microstructures formed by macroscopic and microscopic strain accommodation...

  2. The role of water and mineral-collagen interfacial bonding on microdamage progression in bone.

    Science.gov (United States)

    Luo, Qing; Leng, Huijie; Wang, Xiaodu; Zhou, Yanheng; Rong, Qiguo

    2014-02-01

    Microdamage would be accumulated in bone due to high-intensity training or even normal daily activity, which may consequently cause fragility fracture or stress fracture. On the other hand, microdamage formation serves as a toughening mechanism in bone. However, the mechanisms that control microdamage initiation and accumulation in bone are still poorly understood. Our previous finite element model indicated that different interfacial properties between mineral and collagen in bone may lead to distinct patterns of microdamage accumulation. Therefore, the current study was designed to examine such prediction and to investigate the role of water and mineral-collagen interactions on microdamage accumulation in bone. To address these issues, 48 mice femurs were divided randomly into four groups. These groups were dehydrated or treated with perfluorotripropylamine (PFTA) or NaF solution to change water distribution and mineral-collagen interfacial bonding in bone. After three-point bending fatigue tests, the types of microdamage (i.e., linear microcracks or diffuse damage) formed in bone were compared between different groups. The results suggested that (1) bone tissues with strong mineral-collagen interfacial bonding facilitate the formation of linear microcraks, and (2) water has little contribution to the growth of microcracks. PMID:24122969

  3. Strengthened Response

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    At the International AIDS Conference,China showcases its progress in dealing with the diseaseTwenty-five years after the first report of what has become known as AIDS, representatives of the global AIDS community gathered in Toronto, Canada, to reaffirm their commitments to fight this deadly epidemic.

  4. 碳纤维布约束下钢纤维混凝土与腐蚀钢筋黏结性能的试验研究%Bond behavior of corroded reinforcement in steel fibrous concrete strengthened with CFRP

    Institute of Scientific and Technical Information of China (English)

    邓宗才; 万操

    2012-01-01

    A total of 96 test specimens with embedded reinforcing bars were strengthened by two layer of transverse CFRP (carbon fiber sheets) after accelerated corrosion. Pullout tests on the specimens were conducted to study the effect of CFRP confinement on the bond behavior between corroded reinforcement and steel fibrous concrete, considering the contributions of different elements, including reinforcing bar types, cover depths, corrosion rates, CFRP confinements, and steel fiber. The failure mechanisms were studied. The test results show that CFRP confinements can make the failure mode of deformed reinforcing bar specimens change from steel fibrous concrete splitting to bar pull-out. The main influencing factors of the ultimate bond strength are reinforcement bar types and cover depths, the ultimate bond strength of deformed reinforcement bar specimens is twice as large as that of plain reinforcement bar specimens, and the ultimate bond strength increases when the cover depth changes from 40mm to 60mm. CFRP is effective on slowing down the bond stress reduction rate and maintaining the bond strength. When the corrosion rate is less than 5% , the ultimate bond strength of corroded steel fibrous concrete specimens increases gradually along with the rise of corrosion rate, and decreases when the corrosion rate is higher than 5 %. The steel fiber can increase the bond strength of reinforcement and steel fibrous concrete effectively, and make the descending branch of bond-slip curves much smoother.%为研究碳纤维布加固对腐蚀钢筋与钢纤维混凝土黏结性能的效用,采用外加电流法对96个预埋钢筋-钢纤维混凝土试件进行加速腐蚀,腐蚀完成后横向包裹两层单向碳纤维布;通过拉拔试验研究纤维布约束对腐蚀钢筋与钢纤维混凝土黏结性能的影响规律,并与普通混凝土试验结果进行对比分析,探讨钢筋种类、保护层厚度、腐蚀率、纤维布约束及钢纤维等对

  5. 外粘AFRP布加固RC梁耐冲击性能试验研究%Impact-resistant performance of a RC beam strengthened with externally bonded AFRP sheet

    Institute of Scientific and Technical Information of China (English)

    王兴国; 栗桥介; 朱坤佳

    2015-01-01

    设计了8根钢筋混凝土试验梁,其中2根未加固,6根在梁体受拉面采用不同类型的AFRP布进行外粘加固。然后采用重锤冲击加载试验,重点研究每种试验梁在不同冲击高度下的耐冲击性能。试验结果表明,经过外粘AFRP布加固后,混凝土梁体的挠度变形及塑性变形得到有效抑制,同时这种加固措施还可以延缓梁体裂纹开裂,减轻重锤冲击加载对梁体造成的冲击损伤。另外,AFRP布类型、冲击高度在一定程度上决定着梁体的损伤形态。由此表明,外粘AFRP布加固法能有效提高混凝土梁的耐冲击性,且AFRP布类型与梁体的耐冲击性能直接相关。%Eight RC beams were designed to test their impact-resistant behaviors.6 RC beams were strengthened with externally bonded(EB)aramid fiber reinforced polymer(AFRP)sheet.The falling-weight impact tests were focused on the anti-impact performance of each beam with different impacting heights.The test results showed that the deflection and plastic deformation of RC beams strengthened with EB AFRP sheet can be restrained effectively;at the same time,EB AFRP sheet can slow crack development and mitigate the impact damage caused by falling-weight loading;the RC beams'damage states are dependent upon the type of AFRP sheets and impacting heights to a certain level;EB AFRP sheet can obviously improve the impact-resistant performance of RC beams.

  6. RECENT DEVELOPMENTS IN FRP STRENGTHENING TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    Zhishen WU(吴智深); Hedong Niu

    2004-01-01

    This paper mainly gives a State-of-the-Art report of recent development in FRP strengthening techniques for structural rehabilitation by starting with a brief review on some achievements in clarifying bonding/debonding mechanisms and developing evaluation/design methodology for predicting debonding failure caused by intermedioate flexural cracks of con crete.Due to some drawbacks of current FRP bonding technique,two effective FRP strengthening methods,i.e.FRP prestressing and hybrid strengthening techniques,are investigated in detail to make full advantage of FRP composite materials.Combining with the newly develiped PBO fiber sheets,a more effective prestressing method is established as compared with carbon fiber sheets,a more effective prestressing method is established as compared with carbon fiber sheets,where several anchorage treatments are also established to prevent anchorage bond failure due to high shear stress concentration after release of prestressed FRP ends.In addition,the fatigue performance of RC beams externally strenghened with prestressed PBO fiber sheets is experimentally studied.For the developments of hybrid composites and their strengthening methods,both experimental and analytical studies are performed to clarify the hybrid strengthening behavior in structures.

  7. Chemical activation of molecules by metals: Experimental studies of electron distributions and bonding. Technical progress report, March 1, 1992--February 28, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Lichtenberger, D.L.

    1997-06-01

    During this period of the project we have (1) accomplished the high-resolution gas phase photoelectron spectra of C{sub 60} and C{sub 70}, (2) characterized the electronic features of imaging C{sub 60} on gold by STM, (3) evaluated the orbital distributions of C{sub 60} and the bonding interactions with metals, (4) revealed details of the bonding of phosphines to metals, including the subtleties of a geometrical twist in sterically crowded situations, (5) determined the formal electron distribution in the bonding of {eta}{sup 3} -cyclopropenyl with metals, (6) related gas-phase ionization energies to electron transfer kinetics and ion salvation thermochemistry of metallocenes, (7) correlated lone-pair ionization energies with proton affinities for a variety of amino acids and related compounds, (8) examined sigma-pi interactions in non-conjugated polyalkynes, (9) characterized extensive metal-ligand {pi} interactions in metal-acetylide compounds, and (10) continued to develop the experimental and theoretical methods for these studies. All of these studies have contributed significantly to expanding our understanding of the electronic structure and bonding of organic molecules and the ways this electronic structure is altered by interaction with metals. Further developments in the instrumentation and methods of gas phase and surface photoelectron spectroscopy are underway. Most notable is the progress on the new gas phase photoelectron spectrometer that combines improved capabilities for He I/He II UPS, XPS, and Auger investigations of organometallic molecules.

  8. Flexural Strengthening of RC Slabs with Prestressed CFRP Strips Using Different Anchorage Systems

    Directory of Open Access Journals (Sweden)

    José Sena-Cruz

    2015-10-01

    Full Text Available Externally Bonded Reinforcement (EBR technique has been widely used for flexural strengthening of concrete structures by using carbon fiber-reinforced polymers (CFRP. EBR technique offers several structural advantages when the CFRP material is prestressed. This paper presents an experimental and numerical study on reinforced (RC slabs strengthened in flexure with prestressed CFRP strips as a structural strengthening system. The strips are applied as an externally bonded reinforcement (EBR and anchored with either a mechanical or a gradient anchorage. The former foresees metallic anchorage plates fixed to the concrete substrate, while the latter is based on an accelerated epoxy resin curing followed by a segment-wise prestress force decrease at the strip ends. Both anchorage systems, in combination with different CFRP strip geometries, were subjected to static loading tests. It could be demonstrated that the composite strip’s performance is better exploited when prestressing is used, with slightly higher overall load carrying capacities for mechanical anchorages than for the gradient anchorage. The performed investigations by means of a cross-section analysis supported the experimental observation that in case a mechanical anchorage is used, progressive strip debonding changes the fully bonded configuration to an unbonded end-anchored system. The inclusion of defined debonding criteria for both the anchorage zones and free length between the anchorage regions allowed to precisely capture the ultimate loading forces.

  9. Behaviour of RC beams shear strengthening with NSM CFRP laminates

    OpenAIRE

    Dias, Salvador J. E.; Barros, Joaquim A. O.

    2008-01-01

    The effectiveness of the Near Surface Mounted (NSM) technique with Carbon Fiber Reinforced Polymer (CFRP) laminates for the shear strengthening of T cross section reinforced concrete (RC) beams is assessed by experimental research. The influence of the percentage and inclination of CFRP laminates on the shear strengthening contribution was evaluated. The experimental program also includes beams strengthened according to the externally bonded reinforcement (EBR) technique in ord...

  10. Study of the Tensile Properties of CFRP Strengthened Steel Plates

    OpenAIRE

    Yiyan Lu; Weijie Li; Shan Li; Xiaojin Li; Tao Zhu

    2015-01-01

    This paper presents the experimental results of steel plates strengthened with carbon fiber reinforced polymer (CFRP) sheets under tensile load. The number of CFRP layers (ranging from one to four), strengthening schemes (single-sided and double-sided bonding), and temperatures (ranging from 25 to 120 °C) were investigated. Results showed that the number of CFRP layers and strengthening schemes had insignificant effects on failure modes of specimens. The failure modes were dominated by the de...

  11. CFRP strengthened openings in two-way concrete slabs

    DEFF Research Database (Denmark)

    Enochsson, O.; Lundqvist, J.; Täljsten, Björn;

    2006-01-01

    Rehabilitation and strengthening of concrete structures with externally bonded fibre reinforced polymers (FRPs) has been a viable technique for at least a decade. An interesting and useful application is strengthening of slabs or walls where openings are introduced. In these situations, FRP sheet...

  12. EXPERIMENTAL STUDY ON SHEAR PROPERTIES OF REINFORCED CONCRETE (RC) AND PARTIAL PRESTRESSED CONCRETE (PPC)BEAMS STRENGTHENED WITH EXTERNALLY BONDED CFRP STRIPS%CFRP板加固RC&PPC梁抗剪性能试验研究

    Institute of Scientific and Technical Information of China (English)

    宗周红; 程怡; 黄学漾; 林于东

    2013-01-01

    An experimental study and nonlinear finite element analysis including reinforced concrete (RC) beams and partial prestressed concrete (PPC) beams strengthened with CFRP strips were carried out under static loading.The influences of damage degree,ratio of shear span,stirrup ratio,and level of effective prestressing on the shear characteristics of these strengthened beams were investigated.Some important conclusions were extracted from the testing and numerical analysis and listed as follows:1) The inclined cracking development can be effectively restrained using the proposed strengthening method with CFRP strips,and the shear load-carrying capacity and ductility of the strengthened RC&PPC beams can be effectively improved.2) The synclinal cracking load,yielding loads of the stirrup,and the shear load-carrying capacity of RC beams strengthened after the damage would be enhanced while the ratios of shear span becoming smaller and stirrup ratio becoming larger.3)The improvements of shear carrying-capacity of PPC beams strengthened with CFRP strips would become larger if the level of effective prestressing increasing.4) The proposed nonlinear fimite element (FE) model can better predict the shear performance of strengthened RC&PPC beams,and the results from FE model can correlate very well with those from testing.5) The strength of CFRP strips should be effectively reduced during the shear strengthening design of the practical engineering cases.%通过10片普通钢筋混凝土(RC)梁及4片部分预应力混凝土(PPC)梁采用CFRP板抗剪加固的试验研究和非线性有限元分析,研究不同损伤程度、剪跨比、配箍率及预应力水平等因素对CFRP板加固RC&PPC梁抗剪性能的影响.结果表明:采用CFRP板对RC&PPC梁进行抗剪加固能够有效抑制斜裂缝的开展,提高加固梁斜截面抗剪承载能力,并改善梁的延性;RC梁损伤后加固,随着配箍率的增大以及剪跨比的减小,将提高加固RC梁的斜向开裂

  13. Strengthening of defected beam–column joints using CFRP

    Directory of Open Access Journals (Sweden)

    Mohamed H. Mahmoud

    2014-01-01

    Full Text Available This paper presents an experimental study for the structural performance of reinforced concrete (RC exterior beam–column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP. The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam–column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity.

  14. Strengthening of defected beam-column joints using CFRP.

    Science.gov (United States)

    Mahmoud, Mohamed H; Afefy, Hamdy M; Kassem, Nesreen M; Fawzy, Tarek M

    2014-01-01

    This paper presents an experimental study for the structural performance of reinforced concrete (RC) exterior beam-column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP). The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam-column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM) CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity. PMID:25685473

  15. Strengthening of defected beam–column joints using CFRP

    Science.gov (United States)

    Mahmoud, Mohamed H.; Afefy, Hamdy M.; Kassem, Nesreen M.; Fawzy, Tarek M.

    2013-01-01

    This paper presents an experimental study for the structural performance of reinforced concrete (RC) exterior beam–column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP). The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam–column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM) CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity. PMID:25685473

  16. CFRP Mechanical Anchorage for Externally Strengthened RC Beams under Flexure

    Science.gov (United States)

    Ali, Alnadher; Abdalla, Jamal; Hawileh, Rami; Galal, Khaled

    De-bonding of carbon fiber reinforced polymers (CFRP) sheets and plates from the concrete substrate is one of the major reasons behind premature failures of beams that are externally strengthened with such CFRP materials. To delay or prevent de-bonding and therefore enhancing the load carrying capacity of strengthened beams, several anchorage systems were developed and used. This paper investigates the use of CFRP mechanical anchorage of CFRP sheets and plates used to externally strengthen reinforced concrete beams under flexure. The pin-and-fan shape CFRP anchor, which is custom-made from typical rolled fiber sheets and bundles of loose fiber is used. Several reinforced concrete beams were casted and tested in standard four-point bending scheme to study the effectiveness of this anchorage system. The beams were externally strengthened in flexure with bonded CFRP sheets and plates and then fastened to the soffit of the beams' using various patterns of CFRP anchors. It is observed that the CFRP plates begins to separate from the beams as soon as de-bonding occurs in specimens without CFRP anchors, while in beams with CFRP anchors de-bonding was delayed leading to increase in the load carrying capacity over the un-anchored strengthened beams.

  17. Strengthening Resilience in Families

    Science.gov (United States)

    Guild, Diane; Espiner, Deborah

    2014-01-01

    Rolling with Resilience (RwR) provides a springboard for developing strategies that build strengths and supports to foster developmental assets in children and youth (Benson, Scales, & Roehlkepartain, 2011). In Circle of Courage terms, resilience is strengthened by opportunities for Belonging, Mastery, Independence, and Generosity (Brendtro,…

  18. Strengthening America's Families.

    Science.gov (United States)

    Alvarado, Rose; Kumpfer, Karol

    2000-01-01

    Improving parenting practices and the family environment is the most effective, enduring strategy for combating juvenile delinquency. Describes the Office of Juvenile Justice and Delinquency Prevention's Strengthening America's Families Initiative. Highlights several family-focused prevention programs identified as exemplary, explaining how they…

  19. Protection of RC elements strengthened with CFRP against high temperatures

    OpenAIRE

    Aguiar, J. L. Barroso de; Gorski, M.; Camões, Aires; Vaz, Nelson; Majewski, S.

    2007-01-01

    The strengthening of RC elements with CFRP is a technique that has been acquiring more and more potential. The bond between the CFRP laminates and the concrete support is usually made with epoxy adhesives. However, it is in this part that the integrity of the system can be affected, namely by exposure to high temperatures. In order to evaluate the thermal behaviour, reference RC and CFRP strengthened RC specimens were tested. After cyclical thermal expositions, with temperatures rising betwee...

  20. Limit analysis on FRP-strengthened RC members

    OpenAIRE

    D. De Domenico; A.A.Pisano; P. Fuschi

    2014-01-01

    Reinforced concrete (RC) members strengthened with externally bonded fiber-reinforced-polymer (FRP) plates are numerically investigated by a plasticity-based limit analysis approach. The key-concept of the present approach is to adopt proper constitutive models for concrete, steel reinforcement bars (re-bars) and FRP strengthening plates according to a multi-yield-criteria formulation. This allows the prediction of concrete crushing, steel bars yielding and FRP rupture that may oc...

  1. Experimental Research on the Cracking Behavior of Reinforced Concrete Beams Combination Strengthened with Bonded CFRP and Steel Plate%碳纤维与钢板复合加固钢筋混凝土梁裂缝的试验研究

    Institute of Scientific and Technical Information of China (English)

    熊学玉; 徐海峰

    2012-01-01

    Through the flexural test of one reference beam, three combination strengthened beams and three CFRP reinforced beams, the cracking mechanism and the calculation of crack width of reinforced concrete beams combination strengthened with bonded CFRP and steel plate were studied. Study shows that the crack distance and crack width of strengthened beams are less than those of reference beams, but the secondary crack has increased. The crack growth rate of combination strengthened beams is slower than that of CFRP reinforced beams, which illustrates that combination reinforcement is better than CFRP reinforcement in the role of limiting crack. With the increase of service loading, the crack development speed of reinforcement beams accelerates, and the effect of limiting crack will reduce with it. The maximum crack width curve also appears mutations, which explains that service loading has reduced the effect on limiting crack. However, the service loading has less role of limiting crack on combination reinforcement than CFRP reinforcement. On the basis of traditional crack calculation theory, the adhesive correlation coefficients of combination strengthening and the influence coefficient of service loading are introduced to derive the formula for calculating the crack width of combination strengthened beam considering service loading and adhesive correlation coefficients. The calculation result of crack width is in good agreement with test result. The calculation method is simple and convenient and can be applied to engineering design.%通过1根原梁、3根碳纤维与钢板复合加固梁和3根碳纤维加固梁的受弯性能试验,研究碳纤维与钢板复合加固钢筋混凝土梁的裂缝发展机理及裂缝宽度计算方法.研究表明,加固梁的裂缝间距和裂缝宽度均小于原梁,但次生裂缝有所增加;复合加固梁的裂缝发展速度比碳纤维加固梁缓慢,说明复合加固的限裂作用优于碳纤维;随着负载的增加,

  2. Experimental and Theoretical Analysis of Hollow Steel Columns Strengthening by CFRP

    Directory of Open Access Journals (Sweden)

    Keykha A.H.

    2015-09-01

    Full Text Available The need for strengthening and retrofitting is well known and extensive research is progressing in this field. The reasons for strengthening and retrofitting are numerous: increased loads, changes in use, deterioration, and so on. In recent years, the use of carbon fiber reinforced polymer (CFRP for strengthening has shown to be a competitive method, both regarding structural performance, and economical aspects. Extensive research has been carried out in this field. However, most of the research has been undertaken on concrete structures and for confinement, flexural, and shear strengthening. Limited research has been carried out on steel structures strengthened with CFRP. This paper presents axially loaded steel columns strengthened for increased load. The topic is studied theoretically and through laboratory tests. The theory covers analytical methods. Carbon fiber reinforced polymers has been used to strengthen the columns. The tests have been undertaken on full scale specimens, non-strengthened for reference, partially strengthened and fully strengthened

  3. "I Owe Her So Much; Without Her I Would Be Dead": Developing a Model of Mother-Infant Bonding Following a Maternal Antenatal HIV Diagnosis.

    Science.gov (United States)

    Willcocks, Kate; Evangeli, Michael; Anderson, Jane; Zetler, Sarah; Scourse, Rosalind

    2016-01-01

    Women can face a period of psychological vulnerability following antenatal HIV diagnosis, affecting feelings about both the pregnancy and motherhood. Our study explored the impact of being diagnosed with HIV during pregnancy on mother-infant bonding. Grounded Theory was used to assess perceived challenges and facilitating factors for mother-infant bonding for 10 mothers given an HIV diagnosis during pregnancy. Data analysis led to a model of mother-infant bonding composed of four theoretical codes: (a) facing barriers to bonding, (b) feeling disconnected from the baby, (c) developing a special bond, and (d) strengthening and moving on. Challenges with bonding emerged primarily during early stages after diagnosis and birth, with maternal resilience and positivity about the future developing as the infant HIV testing process progressed. Study recommendations include more timely information regarding vertical transmission and more targeted psychological support along with greater promotion of services to support women diagnosed with HIV antenatally. PMID:26382253

  4. Experimental Study of Axially Loaded RC Short Columns Strengthened With Basalt Fiber Reinforced Polymer (BFRP Sheets

    Directory of Open Access Journals (Sweden)

    Akshay P. Mote

    2014-07-01

    Full Text Available This paper presents the results of experimental study related to the strengthening of R C short columns strengthened with BFRP wrap under axial loading. For strengthening of reinforced concrete columns, total fourteen columns were cast and tested up to failure of the columns under axial loading. The columns were bonded with BFRP sheets in single layer and double layers with various configurations. Out of the fourteen columns two columns were control columns and remaining columns were strengthened with BFRP. The experimental results show that the columns strengthened with BFRP show high load carrying capacity and ductility index. Keywords:

  5. Strengthening regional safeguards

    International Nuclear Information System (INIS)

    Nuclear cooperation between Argentina and Brazil has been growing since the early 1980's and as it grew, so did cooperation with the US Department of Energy (DOE). The Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) was formed in December 1991 to operate the Common System of Accounting and Control of Nuclear Materials (SCCC). In April 1994, ABACC and the DOE signed an Agreement of Cooperation in nuclear material safeguards. This cooperation has included training safeguards inspectors, exchanging nuclear material measurement and containment and surveillance technology, characterizing reference materials, and studying enrichment plant safeguards. The goal of the collaboration is to exchange technology, evaluate new technology in Latin American nuclear facilities, and strengthen regional safeguards. This paper describes the history of the cooperation, its recent activities, and future projects. The cooperation is strongly supported by all three governments: the Republics of Argentina and Brazil and the United States

  6. Strengthening regional safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Palhares, L.; Almeida, G.; Mafra, O. [Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials, Rio de Janeiro (Brazil)] [and others

    1996-08-01

    Nuclear cooperation between Argentina and Brazil has been growing since the early 1980`s and as it grew, so did cooperation with the US Department of Energy (DOE). The Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) was formed in December 1991 to operate the Common System of Accounting and Control of Nuclear Materials (SCCC). In April 1994, ABACC and the DOE signed an Agreement of Cooperation in nuclear material safeguards. This cooperation has included training safeguards inspectors, exchanging nuclear material measurement and containment and surveillance technology, characterizing reference materials, and studying enrichment plant safeguards. The goal of the collaboration is to exchange technology, evaluate new technology in Latin American nuclear facilities, and strengthen regional safeguards. This paper describes the history of the cooperation, its recent activities, and future projects. The cooperation is strongly supported by all three governments: the Republics of Argentina and Brazil and the United States.

  7. Strengthening nuclear security

    International Nuclear Information System (INIS)

    The international situation after the end of the Cold-War has been quite unstable, due to the occurrence of frequent regional conflicts and domestic wars based on ethnic, religious or racial reasons. Further, threats to the would peace and security by non-state actors, like international terrorist groups, have been recognized after 9.11 terrorist attacks to the World Trade Center buildings and to the Pentagon. Utilization of nuclear energy, which encompasses both peaceful uses and military ones, required an establishment of regulatory system, by which risks associated with the development of nuclear energy can be controlled. Accordingly, nuclear safety control system, and then non-proliferation control system has been developed, both in the international level and notional level. In recognition of the present unstable international situations, it is required to establish, maintain and strengthen a system which control nuclear security aspect, in addition to the present systems. (author)

  8. Shear Strengthening of Reinforced Concrete Beams Using GFRP Wraps

    Directory of Open Access Journals (Sweden)

    M. A. A. Saafan

    2006-01-01

    Full Text Available The objective of the experimental work described in this paper was to investigate the efficiency of GFRP composites in strengthening simply supported reinforced concrete beams designed with insufficient shear capacity. Using the hand lay-up technique, successive layers of a woven fiberglass fabric were bonded along the shear span to increase the shear capacity and to avoid catastrophic premature failure modes. The strengthened beams were fabricated with no web reinforcement to explore the efficiency of the proposed strengthening technique using the results of control beams with closed stirrups as a  web reinforcement. The test results of 18 beams are reported, addressing the influence of different shear strengthening schemes and variable longitudinal reinforcement ratios on the structural behavior. The results indicated that significant increases in the shear strength and improvements in the overall structural behavior of beams with insufficient shear capacity could be achieved by proper application of GFRP wraps.

  9. FIRE PROTECTION OF TIMBER STRUCTURES STRENGTHENED WITH FRP MATERIALS

    Directory of Open Access Journals (Sweden)

    Radek Zigler

    2015-12-01

    Full Text Available Modern, progressive methods of structures’ strengthening based on the use of composite materials composed of high strength fibers (carbon, glass, aramid or basalt and matrices based on epoxy resins brings, among many indisputable advantages (low weight, high effectiveness, easy application etc. also some disadvantages. One of the major disadvantages is a low fire resistance of these materials due to the low glass transition temperature Tg of the resin used. Based on an extensive research of strengthening of historic structures with FRP materials [1], the article outlines possible approaches to this problem, especially while strengthening timber load- bearing structures of historic buildings.

  10. Slender reinforced concrete columns strengthened with fibre reinforced polymers

    Science.gov (United States)

    Gajdošová, K.; Bilčík, J.

    2011-06-01

    The requirement for a long life with relatively low maintenance costs relates to the use of building structures. Even though the structure is correctly designed, constructed and maintained, the need for extensions of its lifetime can appear. The preservation of the original structure with a higher level of resistance or reliability is enabled by strengthening. Conventional materials are replaced by progressive composites - mainly carbon fibre reinforced polymers (CFRP). They are used for strengthening reinforced concrete columns in two ways: added reinforcement in the form of CFRP strips in grooves or CFRP sheet confinement and eventually their combination. This paper presents the effect of the mentioned strengthening methods on slender reinforced concrete columns.

  11. Cultural Exchange Strengthens Ties

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Year of Chinese Culture in Australia is poised to cement bonds between the Chinese and Australians As the Year of Australian Culture in China drew to a close in June,the Year of Chinese Culture in Australia,titled Experience China,came ons tage to showcase the rich variety of China’s traditional and contemporary culture to the Australians.The opening ceremony of the event was held on June 24 at the Sydney State Theater.It featured famous Chinese dancer Yang Liping’s original dance drama The Legend of Shangri-La.The Year of Chinese Culture in Australiais by far the largest Chinese cultural festival

  12. Experimental Study of Axially Loaded RC Short Columns Strengthened With Basalt Fiber Reinforced Polymer (BFRP) Sheets

    OpenAIRE

    Akshay P. Mote; H. S. JADHAV

    2014-01-01

    This paper presents the results of experimental study related to the strengthening of R C short columns strengthened with BFRP wrap under axial loading. For strengthening of reinforced concrete columns, total fourteen columns were cast and tested up to failure of the columns under axial loading. The columns were bonded with BFRP sheets in single layer and double layers with various configurations. Out of the fourteen columns two columns were control columns and remaining colum...

  13. Textile-reinforced mortar (TRM) versus fiber-reinforced polymers (FRP) in shear strengthening of concrete beams

    OpenAIRE

    Tetta, Z.C.; Koutas, L.N.; Bournas, D.A.

    2015-01-01

    This paper presents an experimental study on shear strengthening of rectangular reinforced concrete (RC) beams with advanced composite materials. Key parameters of this study include: (a) the strengthening system, namely textile-reinforced mortar (TRM) jacketing and fiber-reinforced polymer (FRP) jacketing, (b) the strengthening configuration, namely side-bonding, U-wrapping and full-wrapping, and (c) the number of the strengthening layers. In total, 14 RC beams were constructed and tested un...

  14. Strengthening of two-way reinforced concrete slabs with Textile Reinforced Mortars (TRM)

    OpenAIRE

    Papanicolaou, Catherine; Triantafillou, Thanasis; Papantoniou, Ioannis; Balioukos, Christos

    2009-01-01

    An innovative strengthening technique is applied for the first time in this study to provide flexural strengthening in two-way reinforced concrete (RC) slabs supported on edge beams. The technique comprises external bonding of textiles on the tension face of RC slabs through the use of polymer-modified cement- based mortars. The textiles used in the experimental campaign comprised fabric meshes made of long stitch-bonded fibre rovings in two orthogonal directions. The specimens measured 2 x 2...

  15. Effective Family Strengthening Interventions. Juvenile Justice Bulletin. Family Strengthening Series.

    Science.gov (United States)

    Alvarado, Rose; Kumpfer, Karol L.

    This bulletin summarizes the results of a training and technology transfer program focussing on strengthening families for the prevention of delinquency. A national search was conducted for representative family strengthening programs, and through a process that involved national conferences, regional training sessions, and technical assistance,…

  16. Strengthening safeguards information evaluation

    International Nuclear Information System (INIS)

    The strengthening of safeguards should not be limited to the verification of explicit declarations made by the States. Additional information should guide the IAEA to set priorities for further investigations. Not only all aspects of the State's nuclear programme, including the application of safe, secure and transparent nuclear management, but also the level of compliance with other verifiable treaties, political motivation, economic capabilities, international relations and ties, co-operative attitude to safeguards, and general openness and transparency should be included. The evaluation of the diverse forms of information from different sources requires new reliable processes that will result in a high credibility and detection probability. The IAEA uses the physical model for the evaluation of the technical information, and proposed also Fuzzy Logic, or Calculation with Words, to handle the information. But for the evaluation it is questioned whether fuzziness could lead to a crisp judgement. In this paper an objective method of information evaluation is proposed, which allows to integrate different kinds of information and to include calibration and tests in the establishment of the evaluation process. This method, Delta, uses elicitation of a syndicate of experienced inspectors to integrate obvious indicators together with apparently innocent indicators, into a database that forms the core of the evaluation process. Nominal or ordinal scales could be applied to come to an objective and quantifiable result. Experience with this method can in the course of time result in predictive conclusions. 9 refs

  17. Strengthening of Concrete Structures with cement based bonded composites

    DEFF Research Database (Denmark)

    Täljsten, Björn; Blanksvärd, Thomas

    2008-01-01

    improved working environment and better compatibility to the base concrete structure. This study gives an overview of different cement based systems, all with very promising results for structural upgrading. Studied parameters are structural retrofit for bending, shear and confinement. It is concluded that...

  18. Corporate Communication - Strengthening the bond between management and workforce

    OpenAIRE

    Nærland, Kristoffer; Holmen, Ida; Winther, Maj

    2014-01-01

    The project is an analysis of the cultural, communicative and motivational challenges a international company can meet, when the employees is not located the same place, and has to change new site locations every time a project is finished. The analysis is based on focus group interviews made with employees at the international company BIC Electric, using theories from the modern perspective, culture dimension theory by Hofstede, General systems theory by Bertalanffy and Motivation-hygien...

  19. Shear Strengthening Performance of Hybrid FRP-FRCM

    Directory of Open Access Journals (Sweden)

    Kyusan Jung

    2015-01-01

    Full Text Available The effectiveness of a hybrid fiber reinforced polymer- (FRP- fabric reinforced cementitious matrix (FRCM for shear strengthening was investigated though an experimental study. FRP materials of FRCM are usually fabricated in the form of a fabric to enhance the bond strength between the FRP material and the cementitious matrix. The hybrid FRP fabric used in this study consisted of carbon FRP (CFRP and glass FRP (GFRP in warp and weft directions, respectively. A total of 11 beams were fabricated and 8 beams among them were strengthened in shear with externally bonded hybrid FRP-FRCM. The number of plies, the bond types, and the spacing of the hybrid FRP fabric were considered as experimental variables. Additionally, a shear capacity model for a FRCM shear strengthened beam was proposed. The values predicted by the proposed model were compared with those by the ACI 549 code and test results. It was confirmed from the comparison that the proposed model predicted the shear strengthening performance of the hybrid FRP-FRCM more reliably than the ACI 549 code did.

  20. Experimental Study of RC Beams Strengthened with CFRP Sheets Under Sustaining Loads

    Institute of Scientific and Technical Information of China (English)

    WANG Wenwei; LI Guo

    2006-01-01

    Seven reinforced concrete (RC) beams strengthened in flexure using carbon fiber reinforced polymer (CFRP) sheets subjected to different sustaining loads were tested. The effects of initial load and load history on the ultimate strength of strengthened RC beams were examined by externally bonded CFRP sheets. The main experimental parameters included different levels of sustaining load at the time of strengthening, and load history. Experimental results show that sustaining load levels at the time of strengthening have important influences on the ultimate strength of strengthened RC beams. If the initial load is the same, the ultimate strength of RC beams strengthened with CFRP sheets is almost the same regardless of load history at the time of strengthening.

  1. Strengthening Global Approaches to Nuclear Security

    International Nuclear Information System (INIS)

    Despite substantial progress in improving nuclear security in recent years, there is more to be done. The threats of nuclear theft and terrorism remain very real. This paper recommends learning from the much stronger national and international efforts in nuclear safety, and in particular taking steps to build international understanding of the threat; establish effective performance objectives; assure performance; train and certify needed personnel; build security culture and exchange best practices; reduce the number of sites that need to be protected; and strengthen the international framework and continue the dialogue once leaders are no longer meeting regularly at the summit level. (author)

  2. Crack-arresting and Strengthening Mechanism of Hybrid Fiber Reinforced Polymer Sheets in Strengthening of Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    X. B. He

    2013-07-01

    Full Text Available The failure process of reinforced concrete (RC beams is exactly the emergence and propagation process of cracks. According to the principles of Fracture Mechanics, if the cracks were retarded in RC beams, the structure performance would be improved. In this paper, hybrid fiber reinforced polymer (HFRP sheets are proposed to retard crack propagation in RC beams, and the crack-arresting and strengthening mechanism of the HFRP composite in the strengthening of RC beams is revealed, which is substantiated by the finite-element-modelling (FEM analysis and bending improvement of RC beams with externally-bonded hybrid glass/carbon FRP (Hybrid G/C FRP sheets.

  3. Photoinduced hydrogen-bonding dynamics.

    Science.gov (United States)

    Chu, Tian-Shu; Xu, Jinmei

    2016-09-01

    Hydrogen bonding dynamics has received extensive research attention in recent years due to the significant advances in femtolaser spectroscopy experiments and quantum chemistry calculations. Usually, photoexcitation would cause changes in the hydrogen bonding formed through the interaction between hydrogen donor and acceptor molecules on their ground electronic states, and such transient strengthening or weakening of hydrogen bonding could be crucial for the photophysical transformations and the subsequent photochemical reactions that occurred on a time scale from tens of femtosecond to a few nanoseconds. In this article, we review the combined experimental and theoretical studies focusing on the ultrafast electronic and vibrational hydrogen bonding dynamics. Through these studies, new mechanisms and proposals and common rules have been put forward to advance our understanding of the hydrogen bondings dynamics in a variety of important photoinduced phenomena like photosynthesis, dual fluorescence emission, rotational reorientation, excited-state proton transfer and charge transfer processes, chemosensor fluorescence sensing, rearrangements of the hydrogen-bond network including forming and breaking hydrogen bond in water. Graphical Abstract We review the recent advances on exploring the photoinduced hydrogen bonding dynamics in solutions through a joint approach of laser spectroscopy and theoretical calculation. The reviewed studies have put forward a new mechanism, new proposal, and new rule for a variety of photoinduced phenomena such as photosynthesis, dual fluorescence emission, rotational reorientation, excited-state proton transfer and charge transfer, chemosensor fluorescence sensing, and rearrangements of the hydrogen-bond network in water. PMID:27491849

  4. Crack Propagation on ESE(T) Specimens Strengthened with CFRP Sheets

    DEFF Research Database (Denmark)

    Hansen, Christian Skodborg; Jensen, Peter Holmstrøm; Dyrelund, Jens;

    2009-01-01

    In this paper fatigue tests on side notched steel test specimens strengthened with adhesive bonded fibre reinforced polymer (FRP) sheets are presented. The specimens are subject to crack growth both in the steel and bond line. Influence of the load ratio and initial crack length on the overall...

  5. Durability of CFRP strengthened concrete structures under accelerated or environmental ageing conditions

    OpenAIRE

    Benzarti, Karim; QUIERTANT, Marc; Chataigner, Sylvain; Aubagnac, Christophe; Nishizaki, Itaru; Kato, Y.

    2008-01-01

    The durability of concrete slabs strengthened by bonded composite materials has been investigated in the framework of an international cooperation between two French and Japanese research institutes. Time evolution of the concrete/composite adhesive bond strength was studied under both controlled and environmental ageing conditions, by using different mechanical characterization methods. The first results of this ongoing experimental campaign are presented.

  6. Prediction of Flexural Capacity of RC Beams Strengthened in Flexure with FRP Fabric and Cementitious Matrix

    Directory of Open Access Journals (Sweden)

    Kyusan Jung

    2015-01-01

    Full Text Available This paper presents both experimental and analytical research results for predicting the flexural capacity of reinforced concrete (RC beams strengthened in flexure with fabric reinforced cementitious matrix (FRCM. In order to assess the efficiency of the FRCM-strengthening method, six beams were strengthened in flexure with FRCM composite having different amounts and layers of FRP fabric and were tested under four-point loading. From test results, it was confirmed that the slippage between the FRP fabric and matrix occurs at a high strain level, and all of the FRCM-strengthened beams failed by the debonding of the FRCM. Additionally, a new bond strength model for FRCM considering the slippage between fabric and matrix was proposed, using a test database to predict the strengthening performance of the FRCM composite. The prediction of the proposed bond strength model agreed well with the debonding loads of the test database.

  7. Recent Progress in the Research of Transition-Metal-Catalyzed C-CN Bond Cleavage%过渡金属催化的C—CN键断裂的研究进展

    Institute of Scientific and Technical Information of China (English)

    寇学振; 范佳骏; 童晓峰; 沈增明

    2013-01-01

    有机氰化物是一种重要的合成中间体,在药物、农药、染料和活性物质中都有应用.使用廉价、简单、低毒的氰基化合物在过渡金属的催化下通过C-CN键断裂生成复杂的氰化物是合成有机氰化物的重要手段之一.综述了不同过渡金属(如Ni,Pd,Rh,Cu,Ru,Fe,Mo,Co等)催化不同种类的氰基化合物C-CN键断裂的最新研究进展,如含C(sp1)-CN键化合物、C(sp2)-CN键化合物以及C(sp3)-CN键化合物,并对有关的反应机理及C-CN键断裂机理的进展进行了探讨.%Nitriles are an important class of organic compounds which can be found in pharmaceuticals,agrochemicals,dyes,and bioactive compounds.Transition-metal-catalyzed C-CN bond cleavage using inexpensive,simple and less toxic nitriles is one of the most attractive modem methods for the synthesis of complicated organic cyanides.Research progress of transition-metal-catalyzed (Ni,Pd,Rh,Cu,Ru,Fe,Mo,Co) different types of C-CN bond cleavage is reviewed,which includes some organic cyanides containing C(sp1)—CN bond,C(sp2)—CN bond and C(sp3)—CN bond.The C-CN cleavage mechanisms are also discussed in this review.

  8. Study of a reinforced concrete beam strengthened using a combination of SMA wire and CFRP plate

    Science.gov (United States)

    Liu, Zhi-qiang; Li, Hui

    2006-03-01

    Traditional methods used for strengthening of reinforced concrete (RC) structures, such as bonding of steel plates, suffer from inherent disadvantages. In recent years, strengthening of RC structures using carbon fiber reinforced polymer (CFRP) plates has attracted considerable attentions around the world. Most existing research on CFRP plate bonding for flexural strengthening of RC beams has been carried out for the strength enhancement. However, little research is focused on effect of residual deformations on the strengthening. The residual deformations have an important effect on the strengthening by CFRP plates. There exists a very significant challenge how the residual deformations are reduced. Shape memory alloy (SMA) has showed outstanding functional properties as an actuator. It is a possibility that SMA can be used to reduce the residual deformation and make cracks of concrete close by imposing the recovery forces on the concrete in the tensile zone. It is only an emergency damage repair since the SMA wires need to be heated continuously. So, an innovative method of a RC beam strengthened by CFRP plates in combination with SMA wires was first investigated experimentally in this paper. In addition, the nonlinear finite element software of ABAQUS was employed to further simulate the behavior of RC beams strengthened through the new strengthening method. It can be found that this is an excellent and effective strengthening method.

  9. Durability of concrete structures strengthened with FRP laminates

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the fast freeze-thaw cycling test, the alkaline immersion test, the water immersion test and the wet-thermal exposure test, the influence of aggressive environments on mechanical behavior of FRP was studied. CFRP specimens subjected to aggressive environments showed good durability with no significant degradation in tensile strength and modulus; however, GFRP specimens exhibited a little decrease in mechanical property after aggressive environments exposure. Based on the fast freeze-thaw cycling test and the wet-thermal exposure test, the influence of aggressive environments on the bond behavior between FRP and concrete, mechanical behavior of concrete beams and columns strengthened with FRP laminates was studied. The results showed that the bond strength had a significant decrease compared with those specimens kept at room temperature, and the specimens strengthened with FRP exhibited good durability.

  10. Shear Strengthening of Concrete Structures with the use of mineral based composites

    DEFF Research Database (Denmark)

    Blanksvärd, Thomas; Täljsten, Björn; Carolin, Anders

    2009-01-01

    Rehabilitation and strengthening of concrete structures have become more common during the last 10-15 years, partly due to a large stock of old structures and partly due to concrete deterioration. Also factors such as lack of understanding and the consequences of chloride attack affect the need for...... rehabilitation. In addition, more traffic and heavier loads lead to the need for upgrading. Existing externally bonded strengthening systems using FRP (fiber reinforced polymers) and epoxy as bonding agents have been proven to be a good approach to repair and strengthen concrete structures. However, the use of...... epoxy bonding agents has some disadvantages in the form of incompatibilities with the base concrete. It is therefore of interest to substitute epoxy with systems that have better compatibility properties with the base concrete, e.g. cementitious bonding agents. This paper presents a study on reinforced...

  11. Effectiveness of external unbonded reinforcement retrofitted to rc beams for flexural strengthening--experimental investigation

    International Nuclear Information System (INIS)

    The paper presents the effectiveness of the strengthening technique by way of retrofitting external unbounded non-prestressed conventional reinforcement. The focus of the study remains confined to effectiveness under varying parameters at ultimate only, through an experimental study. The changed structural behaviour and the effect of varying parameters have been discussed before presenting the results of an experimental study comprising of 30 simply supported reinforced concrete beam specimen tested under four point bending. The analysis of results demonstrated the effectiveness of the strengthening technique in terms of delay in yielding of bonded reinforcement, strengthening ratio and ductility of the strengthened beams under varying parameters. The technique thus has been shown to have promise as a strengthening technique for flexural strengthening of reinforced concrete beams. (author)

  12. 基于增氧的潜流人工湿地强化措施研究进展%Research Progress on Environment and Protection Based on Strengthening Strategies of Oxygen Enriched Subsurface Constructed Wetlands

    Institute of Scientific and Technical Information of China (English)

    周佚芳; 甄葆崇; 李怀正; 陈珂莉

    2014-01-01

    指出了人工湿地是一种行之有效的农村污水分散式处理措施,但氧的缺乏在一定程度上制约了人工湿地的处理效率以及应用范围。在研究大量文献的基础上,归纳了人工湿地的氧来源及各来源的贡献水平,并综述了近年来国内外为改善湿地内部氧环境,对湿地结构上及运行模式上进行的改良,并从复氧原理、复氧能力、存在的问题等角度对各强化措施进行了介绍:主要强化措施有跌水复氧、通气管复氧、人工曝气、变浸润线运行与间歇进水方式。目前结构上的改良存在复氧能力有限、增加管理运行费用、增加施工难度等问题;运行模式的改变能在不过分增加额外投入的前提下得到良好的复氧效果并提升湿地处理效率,也可与结构上的改良共同使用。但是间歇进水的脉冲频率对于不同污染物的去除的影响还缺乏深入的定量研究。%Constructed wetland is an effective distributed processing measure for the rural sewage ,but the lack of oxygen limits the pollutant removal efficiency and the application range of constructed wetlands to some extent .Based on extensive review of literature , the article concludes constructed wetland's main sources of oxygen and the contribution level of each source . In addition , the article reviews the improvement of wetland structure and operational mode which aims to perfect the wetland's inside oxygen environment ,and introduces the strengthening strategies through several aspects ,including reoxygenation mechanisms ,reoxygenation capacity and the existing defects of the configuration innovations ,etc/the main strengthening strategies include which includes water -dropping reoxygenation ,breather pipe reoxygenation ,artificial aeration ,modified saturation line operation and batch influent method . The existing configuration innovations have some major disadvantages , such as limited reoxygenation ability

  13. Solute strengthening at high temperatures

    Science.gov (United States)

    Leyson, G. P. M.; Curtin, W. A.

    2016-08-01

    The high temperature behavior of solute strengthening has previously been treated approximately using various scaling arguments, resulting in logarithmic and power-law scalings for the stress-dependent energy barrier Δ E(τ ) versus stress τ. Here, a parameter-free solute strengthening model is extended to high temperatures/low stresses without any a priori assumptions on the functional form of Δ E(τ ) . The new model predicts that the well-established low-temperature, with energy barrier Δ {{E}\\text{b}} and zero temperature flow stress {τy0} , transitions to a near-logarithmic form for stresses in the regime 0.2range of stresses. The model is applied to literature data on solution strengthening in Cu alloys and captures the experimental results quantitatively and qualitatively. Most importantly, the model accurately captures the transition in strength from the low-temperature to intermediate-temperature and the associated transition for the activation volume. Overall, the present analysis unifies the different qualitative models in the literature and, when coupled with the previous parameter-free solute strengthening model, provides a single predictive model for solute strengthening as a function of composition, temperature, and strain rate over the full range of practical utility.

  14. The strengthening effect of percutaneous vertebroplasty

    Energy Technology Data Exchange (ETDEWEB)

    Dean, J.R.; Ison, K.T.; Gishen, P

    2000-06-01

    AIM: To examine whether single-needle vertebroplasty is effective in strengthening vertebrae. MATERIALS AND METHODS: Four adjacent intact lumbar vertebrae were removed from each of nine adult post-mortem subjects. One or two vertebra of each set was injected with low viscosity acrylic bone cement using a single-track posterolateral approach. Vertebral strength was measured during constant rate axial compression. RESULTS: Single-needle injection delivered different quantities of cement (1-8 ml) in an asymmetric distribution. Injected vertebrae were stronger than controls in 10 out of 12 cases (P < 0.01), suggesting that cement injection increases the load needed to cause initial vertebral fracture. Compression was continued past the point of initial failure, to simulate progressive vertebral collapse. Injected specimens were more resistant to deformation than control specimens (P < 0.05), most of which initially deformed with little increase in load. CONCLUSION: Single-track injection of bone cement appeared to strengthen vertebrae against both initial failure and subsequent collapse. The magnitude of strength increase from vertebroplasty was variable, and did not correlate with the volume of cement injected. Further investigation is needed to optimize the technique. Gishen, P. (2000)

  15. Bond Boom

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Ministry of Finance recently kick-started a pilot program allowing local governments of Shanghai and Shenzhen,and Zhejiang and Guangdong provinces to issue bonds for the first time.How will the new policy affect fiscal capacities of local governments and the broader economy? What else should the country do to build a healthy bond market? Economists and experts discussed these issues in an interview with the Shanghai Securities Journal.Edited excerpts follow.

  16. Bond Boom

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Ministry of Finance recently kick-started a pilot program allowing local governments of Shanghai and Shenzhen, and Zhejiang and Guangdong provinces to issue bonds for the first time. How will the new policy affect fiscal capacities of local governments and the broader economy? What else should the country do to build a healthy bond market? Economists and experts discussed these issues in an interview with the ShanghaiSecuritiesJournal. Edited excerpts follow:

  17. On peptide bond formation, translocation, nascent protein progression and the regulatory properties of ribosomes. Derived on 20 October 2002 at the 28th FEBS Meeting in Istanbul.

    Science.gov (United States)

    Agmon, Ilana; Auerbach, Tamar; Baram, David; Bartels, Heike; Bashan, Anat; Berisio, Rita; Fucini, Paola; Hansen, Harly A S; Harms, Joerg; Kessler, Maggie; Peretz, Moshe; Schluenzen, Frank; Yonath, Ada; Zarivach, Raz

    2003-06-01

    High-resolution crystal structures of large ribosomal subunits from Deinococcus radiodurans complexed with tRNA-mimics indicate that precise substrate positioning, mandatory for efficient protein biosynthesis with no further conformational rearrangements, is governed by remote interactions of the tRNA helical features. Based on the peptidyl transferase center (PTC) architecture, on the placement of tRNA mimics, and on the existence of a two-fold related region consisting of about 180 nucleotides of the 23S RNA, we proposed a unified mechanism integrating peptide bond formation, A-to-P site translocation, and the entrance of the nascent protein into its exit tunnel. This mechanism implies sovereign, albeit correlated, motions of the tRNA termini and includes a spiral rotation of the A-site tRNA-3' end around a local two-fold rotation axis, identified within the PTC. PTC features, ensuring the precise orientation required for the A-site nucleophilic attack on the P-site carbonyl-carbon, guide these motions. Solvent mediated hydrogen transfer appears to facilitate peptide bond formation in conjunction with the spiral rotation. The detection of similar two-fold symmetry-related regions in all known structures of the large ribosomal subunit, indicate the universality of this mechanism, and emphasizes the significance of the ribosomal template for the precise alignment of the substrates as well as for accurate and efficient translocation. The symmetry-related region may also be involved in regulatory tasks, such as signal transmission between the ribosomal features facilitating the entrance and the release of the tRNA molecules. The protein exit tunnel is an additional feature that has a role in cellular regulation. We showed by crystallographic methods that this tunnel is capable of undergoing conformational oscillations and correlated the tunnel mobility with sequence discrimination, gating and intracellular regulation. PMID:12787020

  18. Behavior and Analysis of Self-Consolidated Reinforced Concrete Deep Beams Strengthened in Shear

    OpenAIRE

    N. Y. Elwkad; Meleka, N. N.; Heiza, Kh. M.

    2012-01-01

    In this study, a new shear strengthening technique for reinforced self-compacting concrete (RSCC) deep beams was suggested and compared with some traditional techniques. An experimental test program consists of sixteen specimens of RSCC deep beams strengthened by different materials such as steel, glass, and carbon fiber reinforced polymers (GFRP and CFRP) was executed. Externally bonded layers (EBLs) and near-surface mounted reinforcement (NSMR) were used as two different techniques. The eff...

  19. Strategy for Strengthening Farmer Groups by Institutional Strengthening

    OpenAIRE

    Purbayu Budi Santoso; Darwanto Darwanto

    2015-01-01

    Agriculture sector becomes a spotlight because this sector will be full of potential but the welfare of farmers who become the leading actor is not guaranteed and has a poor tendency. The purpose of this study is to formulate strategies to strengthen farmers' groups in order to create the marketing of the agricultural sector that benefit farmers. The method used to achieve this goal is to use a qualitative approach and Analytical Network Process. In addition to the secondary data obtained fro...

  20. Distinguishing Bonds.

    Science.gov (United States)

    Rahm, Martin; Hoffmann, Roald

    2016-03-23

    The energy change per electron in a chemical or physical transformation, ΔE/n, may be expressed as Δχ̅ + Δ(VNN + ω)/n, where Δχ̅ is the average electron binding energy, a generalized electronegativity, ΔVNN is the change in nuclear repulsions, and Δω is the change in multielectron interactions in the process considered. The last term can be obtained by the difference from experimental or theoretical estimates of the first terms. Previously obtained consequences of this energy partitioning are extended here to a different analysis of bonding in a great variety of diatomics, including more or less polar ones. Arguments are presented for associating the average change in electron binding energy with covalence, and the change in multielectron interactions with electron transfer, either to, out, or within a molecule. A new descriptor Q, essentially the scaled difference between the Δχ̅ and Δ(VNN + ω)/n terms, when plotted versus the bond energy, separates nicely a wide variety of bonding types, covalent, covalent but more correlated, polar and increasingly ionic, metallogenic, electrostatic, charge-shift bonds, and dispersion interactions. Also, Q itself shows a set of interesting relations with the correlation energy of a bond. PMID:26910496

  1. Initial Semantics for Strengthened Signatures

    CERN Document Server

    Hirschowitz, André; 10.4204/EPTCS.77.5

    2012-01-01

    We give a new general definition of arity, yielding the companion notions of signature and associated syntax. This setting is modular in the sense requested by Ghani and Uustalu: merging two extensions of syntax corresponds to building an amalgamated sum. These signatures are too general in the sense that we are not able to prove the existence of an associated syntax in this general context. So we have to select arities and signatures for which there exists the desired initial monad. For this, we follow a track opened by Matthes and Uustalu: we introduce a notion of strengthened arity and prove that the corresponding signatures have initial semantics (i.e. associated syntax). Our strengthened arities admit colimits, which allows the treatment of the \\lambda-calculus with explicit substitution.

  2. Initial Semantics for Strengthened Signatures

    Directory of Open Access Journals (Sweden)

    André Hirschowitz

    2012-02-01

    Full Text Available We give a new general definition of arity, yielding the companion notions of signature and associated syntax. This setting is modular in the sense requested by Ghani and Uustalu: merging two extensions of syntax corresponds to building an amalgamated sum. These signatures are too general in the sense that we are not able to prove the existence of an associated syntax in this general context. So we have to select arities and signatures for which there exists the desired initial monad. For this, we follow a track opened by Matthes and Uustalu: we introduce a notion of strengthened arity and prove that the corresponding signatures have initial semantics (i.e. associated syntax. Our strengthened arities admit colimits, which allows the treatment of the λ-calculus with explicit substitution.

  3. CFRP strengthening of concrete beams - testing in sub-zero temperature

    DEFF Research Database (Denmark)

    Täljsten, Björn; Carolin, A.

    2007-01-01

    Strengthening structures with epoxy bonded Carbon Fibre-Reinforced Polymer (CFRP) plates and sheets are today a well-known and over the world common used method to improve a structure performance. The composite materials used for strengthening are very light and easy to handle,. have good...... compared to the summer period? In this paper the last issue will be addressed. CFRP strengthen concrete beams have been tested in sub-zero temperature and loaded up to failure. The cold climate tests are then compared with similar beams tested in room climate. From the tests no significantly difference...

  4. Strengthening of oral health systems

    DEFF Research Database (Denmark)

    Petersen, Poul Erik

    2014-01-01

    diseases must be provided through financially fair primary health care and public health intervention. Integrated approaches are the most cost-effective and realistic way to close the gap in oral health between rich and poor. The World Health Organization (WHO) Oral Health Programme will work with the...... newly established WHO Collaborating Centre, Kuwait University, to strengthen the development of appropriate models for primary oral health care. © 2014 P.E. Petersen, Geneva....

  5. Sleep On It: How Snoozing Strengthens Memories

    Science.gov (United States)

    ... External link, please review our exit disclaimer . Subscribe Sleep On It How Snoozing Strengthens Memories When you ... the best way to remember it is to sleep on it. That’s because sleeping helps strengthen memories ...

  6. A mechanical model for FRP-strengthened beams in bending

    Directory of Open Access Journals (Sweden)

    P. S. Valvo

    2012-10-01

    Full Text Available We analyse the problem of a simply supported beam, strengthened with a fibre-reinforced polymer (FRP strip bonded to its intrados and subjected to bending couples applied to its end sections. A mechanical model is proposed, whereby the beam and FRP strip are modelled according to classical beam theory, while the adhesive and its neighbouring layers are modelled as an interface having a piecewise linear constitutive law defined over three intervals (elastic response – softening response – debonding. The model is described by a set of differential equations with appropriate boundary conditions. An analytical solution to the problem is determined, including explicit expressions for the internal forces, displacements and interfacial stresses. The model predicts an overall non-linear mechanical response for the strengthened beam, ranging over several stages: from linearly elastic behaviour to damage, until the complete detachment of the FRP reinforcement.

  7. Limit analysis on FRP-strengthened RC members

    Directory of Open Access Journals (Sweden)

    D. De Domenico

    2014-07-01

    Full Text Available Reinforced concrete (RC members strengthened with externally bonded fiber-reinforced-polymer (FRP plates are numerically investigated by a plasticity-based limit analysis approach. The key-concept of the present approach is to adopt proper constitutive models for concrete, steel reinforcement bars (re-bars and FRP strengthening plates according to a multi-yield-criteria formulation. This allows the prediction of concrete crushing, steel bars yielding and FRP rupture that may occur at the ultimate limit state. To simulate such limitstate of the analysed elements, two iterative methods performing linear elastic analyses with adaptive elastic parameters and finite elements (FEs description are employed. The peak loads and collapse mechanisms predicted for FRP-plated RC beams are validated by comparison with the corresponding experimental findings.

  8. Repair and Strengthening of Reinforced Concrete Structures Using CFRP Plates

    International Nuclear Information System (INIS)

    The infrastructure's increasing decay is frequently combined with the need for upgrading so that structures can meet more stringent design requirements (e.g., increased traffic volumes in bridges exceeding the initial design loads), and hence the aspect of civil engineering infrastructure renewal has received considerable attention over the past few years throughout the world. At the same time, seismic retrofit has become equally important, especially in the areas of high seismic risk. The worldwide acceptance of external plate bonding using CFRP laminates for the repair of under strengthened or damaged reinforced concrete beams is the real incentive for many investigators to devote a great deal of effort to physically understand the response of such beams under externally applied loads. This paper is aimed towards providing a review of the repair and strengthening of the RC concrete structures using CFRP plates along with introducing the basics of the above mentioned technique

  9. FIRE PROTECTION OF TIMBER STRUCTURES STRENGTHENED WITH FRP MATERIALS

    OpenAIRE

    Radek Zigler; Marek Pokorný

    2015-01-01

    Modern, progressive methods of structures’ strengthening based on the use of composite materials composed of high strength fibers (carbon, glass, aramid or basalt) and matrices based on epoxy resins brings, among many indisputable advantages (low weight, high effectiveness, easy application etc.) also some disadvantages. One of the major disadvantages is a low fire resistance of these materials due to the low glass transition temperature Tg of the resin used. Based on an extensive research of...

  10. Strengthening Families: Community Strategies That Work

    Science.gov (United States)

    Olson, Maril

    2007-01-01

    Supporting and strengthening families has always been part of the early childhood professional's unique role in the community. NAEYC's Supporting Teachers, Strengthening Families initiative (www.naeyc.org/ece/supporting) is a set of activities designed to provide intentional leadership and education in the family-strengthening approach. The…

  11. Shear Strengthening of RC Beams Using Sprayed Glass Fiber Reinforced Polymer

    OpenAIRE

    Sayed Mohamad Soleimani; Nemkumar Banthia

    2012-01-01

    The effectiveness of externally bonded sprayed glass fiber reinforced polymer (Sprayed GFRP) in shear strengthening of RC beams under quasi-static loading is investigated. Different techniques were utilized to enhance the bond between concrete and Sprayed GFRP, involving the use of through bolts and nuts paired with concrete surface preparation through sandblasting and through the use of a pneumatic chisel prior to Sprayed GFRP application. It was found that roughening the concrete surface us...

  12. New Proposal for Flexural Strengthening of Reinforced Concrete Beams Using CFRP T-Shaped Profiles

    Directory of Open Access Journals (Sweden)

    Renata Kotynia

    2015-11-01

    Full Text Available The purpose of this study was to evaluate the performance of a novel strengthening system using T-shaped carbon fiber reinforced polymer (CFRP profiles. The proposed system successfully combines the advantages of two established strengthening techniques, namely the near surface mounted (NSM and externally bonded (EB methods. The paper presents the experimental results of structural tests carried out on seven flexurally-strengthened and two non-strengthened full-scale reinforced concrete (RC members. Two T-shaped profiles having heights of 15 and 30 mm were applied. The main parameters of concrete strength and composite strengthening ratio were investigated to evaluate the efficiency of the proposed flexural strengthening system. All specimens were tested under a quasi-static six-point bending configuration. The test results showed a significant increase in the load bearing capacity and the stiffness of the RC beams with strengthening and also a notable reduction in maximum deflections. The high tensile strength utilization of the CFRP profiles places this strengthening technique as a promising alternative to other, less structurally-efficient systems.

  13. Moisture and Temperature Effects on Interface Mechanical Properties for External Bonding

    OpenAIRE

    Ueda, Tamon; Shrestha, Justin; Rashid, Khuram; Zhang, Dawei

    2016-01-01

    In order to develop rational guidelines for strengthening by external bonding, it is necessary to clarify longterm performance of interfacial bonding property. In this paper, moisture effects on bonding properties at FRP–concrete interface and temperature/moisture effects on bonding properties at PCM–concrete interface are presented. Shear bond strength of FRP–concrete interface is affected by moisture because resin–concrete adhesion strength is affected by moisture. Among tested CFRP externa...

  14. Diffusion bonding

    Science.gov (United States)

    Anderson, Robert C.

    1976-06-22

    1. A method for joining beryllium to beryllium by diffusion bonding, comprising the steps of coating at least one surface portion of at least two beryllium pieces with nickel, positioning a coated surface portion in a contiguous relationship with an other surface portion, subjecting the contiguously disposed surface portions to an environment having an atmosphere at a pressure lower than ambient pressure, applying a force upon the beryllium pieces for causing the contiguous surface portions to abut against each other, heating the contiguous surface portions to a maximum temperature less than the melting temperature of the beryllium, substantially uniformly decreasing the applied force while increasing the temperature after attaining a temperature substantially above room temperature, and maintaining a portion of the applied force at a temperature corresponding to about maximum temperature for a duration sufficient to effect the diffusion bond between the contiguous surface portions.

  15. Progress in Research of Bacteria Fertilizer Strengthening Resistance of Plants

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Bacteria fertilizer is used most widely among all kinds of microbial fertilizers. We summarize the research headway of bacteria fertilizer. It mainly focuses on bacteria fertilizer improving the stress resistance of plant. Then we can offer basis to research and exploit bacteria fertilizer. These bacteria include azotobacter, photosynthetic bacteria, Bacillus mucilaginosus siliceous, phosphorus bacteria, plant growth-promoting rhizobacteria(PGPR), effective microorganism(EM).

  16. Forecasting for strengthening technological development

    Directory of Open Access Journals (Sweden)

    Aida Mayerly Fúquene Montañez

    2010-05-01

    Full Text Available Producing technological innovation is currently one of the key items in being more competitive. However, production sectors are facing great challenges, including analysing a large amount of available technological and market information regarding the en- vironment for strategic decision-making and being able to launch themselves onto the market with technological developments bringing the desired economic returns. Several tools for analysing information have emerged for reducing the uncertainty of tech- nological and market changes. This article provides conceptual and reflective elements so that forecasting strengthens technolo- gical development (TD. Forecasting is initially proposed as being one of the future methods of analysis having a significant im- pact on decision-making, mainly within the field of economics but which could be extrapolated to making a contribution to TD. The techniques which have been the recent instrument for collecting information for producing forecasting are described, as is work about the concept of surveillance/monitoring and the processes used for coordinating such approaches. It can thus be sta- ted that they provide an excellent basis for strengthening TD by providing platforms for new or improved developments in pro- cesses or products. Reflection about these aspects provides perspectives for implementing technological forecasting (TF in pro- duction systems so that they obtain efficient and concrete results via deterministic methods as input in decision-making in techno- logy regarding its middle- and long-term competitiveness.

  17. Strengthening of old metallic structures in fatigue with prestressed and non-prestressed CFRP laminates

    DEFF Research Database (Denmark)

    Täljsten, Björn; Hansen, Christian Skodborg; Schmidt, Jacob Wittrup

    2009-01-01

    Test results and theoretical considerations on four different configurations of strengthened old steel plates with a centre notch loaded in fatigue are presented in this paper. The main interest of the research was to improve fatigue life by adhesive bonding of CFRP laminates on the steel surface...

  18. System design for strengthening simply supported RC beams in flexure by retrofitting external unbonded conventional reinforcement

    International Nuclear Information System (INIS)

    The paper presents the practical design approach and guidelines for the system design of a novel strengthening technique where external unbounded ordinary reinforcement is retrofitted to reinforced concrete beams for enhancement of flexural capacity of simply supported and cantilever beams of buildings and bridges. The design guidelines for the system hardware along with the practical consideration in applications have been elaborately presented. Suitable design examples have been included demonstrating the suitability of the technique in comparison to steel plate bonding. Strengthening with external unbounded reinforcement has been shown to provide an appreciable increase in the ultimate flexural strength of reinforced concrete beams. Additionally the technique offers greater simplicity and ease of installation in comparison to other widely used strengthening techniques, such as shotcrete with additional tension reinforcement, epoxy bonded steel plates and external unbounded prestressing tendors, where less stringent requirements for deflectors, anchorage and end zones are encountered. (author)

  19. FRP Composites Strengthening of Concrete Columns under Various Loading Conditions

    Directory of Open Access Journals (Sweden)

    Azadeh Parvin

    2014-04-01

    Full Text Available This paper provides a review of some of the progress in the area of fiber reinforced polymers (FRP-strengthening of columns for several loading scenarios including impact load. The addition of FRP materials to upgrade deficiencies or to strengthen structural components can save lives by preventing collapse, reduce the damage to infrastructure, and the need for their costly replacement. The retrofit with FRP materials with desirable properties provides an excellent replacement for traditional materials, such as steel jacket, to strengthen the reinforced concrete structural members. Existing studies have shown that the use of FRP materials restore or improve the column original design strength for possible axial, shear, or flexure and in some cases allow the structure to carry more load than it was designed for. The paper further concludes that there is a need for additional research for the columns under impact loading senarios. The compiled information prepares the ground work for further evaluation of FRP-strengthening of columns that are deficient in design or are in serious need for repair due to additional load or deterioration.

  20. Fatigue behaviour analysis for the durability prequalification of strengthening mortars

    International Nuclear Information System (INIS)

    An innovative laboratory procedure used as a preliminary design stage for the pre-qualification of strengthening mortars applied to historical masonry buildings is described. In the analysis of the behaviour of masonry structures and their constituent materials, increasing importance has been assumed by the study of the long-term evolution of deformation and mechanical characteristics, which may be affected by both loading and environmental conditions. Through static and fatigue tests on mixed specimens historical brick-reinforced mortar it has been possible to investigate the durability of strengthening materials, in order to select, from a range of alternatives, the most suitable for the historical masonry. Cyclic fatigue stress has been applied to accelerate the static creep and to forecast the corresponding creep behaviour of the historical brick-strengthening mortar system under static long-time loading. This methodology has proved useful in avoiding the errors associated with materials that are not mechanically compatible and guarantees the durability of strengthening work. The experimental procedure has been used effectively in the biggest restoration building site in Europe, the Royal Palace of Venaria, and it is in progress of carrying out at the Special Natural Reserve of the Sacro Monte di Varallo, in Piedmont (Italy).

  1. Pi Bond Orders and Bond Lengths

    Science.gov (United States)

    Herndon, William C.; Parkanyi, Cyril

    1976-01-01

    Discusses three methods of correlating bond orders and bond lengths in unsaturated hydrocarbons: the Pauling theory, the Huckel molecular orbital technique, and self-consistent-field techniques. (MLH)

  2. Low temperature GRISM direct bonding

    Science.gov (United States)

    Kalkowski, Gerhard; Harnisch, Gerd; Grabowski, Kevin; Benkenstein, Tino; Ehrhardt, Sascha; Zeitner, Uwe; Risse, Stefan

    2015-09-01

    For spectroscopy in space, GRISM elements -obtained by patterning gratings on a prism surface - are gaining increasing interest. Originally developed as dispersive elements for insertion into an imaging light path without deflecting the beam, they are progressively found in sophisticated multi stage dispersion optics. We report on GRISM manufacturing by joining the individual functional elements -prisms and gratings - to suitable components. Fused silica was used as glass material and the gratings were realized by e-beam lithography und dry etching. Alignment of the grating dispersion direction to the prism angle was realized by passive adjustment. Materials adapted bonds of high transmission, stiffness and strength were obtained at temperatures of about 200°C in vacuum by hydrophilic direct bonding. Examples for bonding uncoated as well as coated fused silica surfaces are given. The results illustrate the great potential of hydrophilic glass direct bonding for manufacturing transmission optics to be used under highly demanding environmental conditions, as typical in space.

  3. Achievements to date in strengthened safeguards

    International Nuclear Information System (INIS)

    There is substantial progress in developing and implementing measures to strengthen the effectiveness and improve the efficiency of the Safeguards System. The measures comprise those to be implemented pursuant to the Agency's legal authority conferred by existing safeguards agreements as well as those to be implemented under the complementary legal authority conferred by Additional Protocols concluded on the basis of Document INFCIRC/540(Corrected). Activities on implementing measures under existing legal authority, particularly with respect to the evaluation of States' nuclear programmes, environmental sampling and the use of remote monitoring for safeguards purposes had been carried continuously ion the recent post. In 1998, additional protocols entered into force with four States (the Holy See, Jordan, New Zealand and Uzbekistan). Additional protocols with a further 27 States were approved by the Board and were awaiting ratification by the respective States. The additional protocol with Australia, which entered into force in December 1997, was being implemented following receipt of its Article 2 declaration. Agency consultations on concluding additional protocols take place with a number of States on a regular basis. As of 1 October 1999, Additional Protocols had been concluded and approved by the Board of Governors with a total of 45 States. Of these, Additional Protocols with 44 States had been signed and five had entered into force. (author)

  4. Finite element analysis of FRP-strengthened RC beams

    Directory of Open Access Journals (Sweden)

    Teeraphot Supaviriyakit

    2004-05-01

    Full Text Available This paper presents a non-linear finite element analysis of reinforced concrete beam strengthened with externally bonded FRP plates. The finite element modeling of FRP-strengthened beams is demonstrated. Concrete and reinforcing bars are modeled together as 8-node isoparametric 2D RC element. The FRP plate is modeled as 8-node isoparametric 2D elastic element. The glue is modeled as perfect compatibility by directly connecting the nodes of FRP with those of concrete since there is no failure at the glue layer. The key to the analysis is the correct material models of concrete, steel and FRP. Cracks and steel bars are modeled as smeared over the entire element. Stress-strain properties of cracked concrete consist of tensile stress model normal to crack, compressive stress model parallel to crack and shear stress model tangential to crack. Stressstrain property of reinforcement is assumed to be elastic-hardening to account for the bond between concrete and steel bars. FRP is modeled as elastic-brittle material. From the analysis, it is found that FEM can predict the load-displacement relation, ultimate load and failure mode of the beam correctly. It can also capture the cracking process for both shear-flexural peeling and end peeling modes similar to the experiment.

  5. Efficient strengthening technique for reinforced concrete slabs

    OpenAIRE

    Bonaldo, Everaldo; Barros, Joaquim A. O.; Lourenço, Paulo B.

    2006-01-01

    A promising strengthening strategy, using carbon fiber reinforced polymer (CFRP) materials, consists in applying CFRP laminate strips into pre-cut slits opened in the concrete cover of the elements to strengthen. This strengthening technique is designated by Near Surface Mounted (NSM) and has been successfully used to increase the flexural and the shear resistance of concrete and masonry structures. The present work describes an efficient strategy, using steel fiber reinforced concrete (SFRC)...

  6. Thermomechanical responses of concrete members strengthened with cfrp sheets

    Science.gov (United States)

    Alqurashi, Abdulaziz

    Strengthening structural members means to be able to carry additional loads. Since, 1990s, a lot of materials and techniques have been established to not only increasing the capacity of member but also facing deterioration. Deterioration has become one of the worst highly maintenance cost. According to The ASCE, 27.1% of all bridges in the United States are not effectual. This is because the high traffic reflects negatively to structural members and cause deterioration of these members. This problem has been cost a lot of money. In addition, FRP has approved that it can increase the capacity of member and overcome some disadvantages such as deterioration. Therefore, CFRP sheet has become widely used. However, high temperatures affect the performance of externally bonded CFRP sheet negatively. Investigation should be carried out on relaxation and flexural performance of members under different temperatures. Therefore, this thesis focus on analyzing and investigating the performance of strengthened members exposed to elevated temperatures (25 to 175 °C). The experimental program was divided to two main parts. First, 144 strengthen concrete blocks 100mm X 150mm X 75mm has been exposed to elevated temperatures. These blocks have two main categories, which are different CFRP sheet width, and different CFRP sheet length. Different CFRP width has three types, which are type 0.25B (25mm x 100mm), type 0.5B (50mm x 100mm) and type 0.75B (75mm x 100mm). Also, Different CFRP length has three types, which are type L e (bonded area of 50 mm by 90mm), 1.25 Le (area of 50mm by 125mm) and type 1.5Le (50mm by 137 mm). Second, studying the performance of RC beams exposed to elevated temperatures.

  7. Fukushima Ministerial Conference Urges Continued Work to Strengthen Nuclear Safety

    International Nuclear Information System (INIS)

    Full text: Strengthening nuclear safety is a continuous process that leaves no room for complacency, the Co-Presidents of the Fukushima Ministerial Conference on Nuclear Safety said in a statement today. Koichiro Gemba, Japan's Minister of Foreign Affairs, and Fadillah bin Haji Yusof, Malaysia's Deputy Minister of Science, Technology and Innovation, released the Co-Presidents' Statement at the conclusion of the Conference's Ministerial Plenary, on day one of the three-day event. ''It was stressed that nuclear safety is a prerequisite for the peaceful uses of nuclear energy, that strengthening nuclear safety is a continuous process and that there should be no complacency in safety matters,'' the statement said. The statement recognized progress reported by Japan in the response to the Fukushima Daiichi accident, including the achievement of the present stable status of the nuclear power station and the significant decrease in radioactive releases at the accident site. It stressed the importance of continued transparency in sharing objective information on the progress of decommissioning the plant, remediation and waste management, and encouraged Japan to lead an international effort to obtain data from the damaged reactors. ''The lessons learned from these activities, through their dissemination and related cooperation with the international community, are expected to contribute to enhancing the safety and effectiveness of future decommissioning and remediation activities worldwide,'' it said. The statement emphasized the importance of strengthening the IAEA's central role in international efforts to enhance global nuclear safety, underlining the Agency's Safety Standards and the IAEA Action Plan on Nuclear Safety. It urged IAEA Member States to strengthen efforts to implement the Action Plan fully, including the use of international peer reviews and putting the recommendations of such reviews into practice. It stressed the ''utmost importance of establishing and

  8. FRP-to-concrete bond behaviour under high strain rates

    OpenAIRE

    Li, Xiaoqin

    2012-01-01

    Fibre reinforced polymer (FRP) composites have been used for strengthening concrete structures since early 1990s. More recently, FRP has been used for retrofitting concrete structures for high energy events such as impact and blast. Debonding at the FRP-to-concrete interface is one of the predominant failure modes for both static and dynamic loading. Although extensive research has been conducted on the static bond behaviour, the bond-slip mechanics under high strain rates is n...

  9. Cross Shear Roll Bonding

    DEFF Research Database (Denmark)

    Bay, Niels; Bjerregaard, Henrik; Petersen, Søren. B;

    1994-01-01

    The present paper describes an investigation of roll bonding an AlZn alloy to mild steel. Application of cross shear roll bonding, where the two equal sized rolls run with different peripheral speed, is shown to give better bond strength than conventional roll bonding. Improvements of up to 20......-23% in bond strength are found and full bond strength is obtained at a reduction of 50% whereas 65% is required in case of conventional roll bonding. Pseudo cross shear roll bonding, where the cross shear effect is obtained by running two equal sized rolls with different speed, gives the same results....

  10. Strengthening entrepreneurship through coaching and developing competencies

    NARCIS (Netherlands)

    Beldman, A.C.G.

    2011-01-01

    Strengthening entrepreneurship is an important strategy for stimulating the transition to sustainable agriculture. But how is that done? One example is the Interactive Strategic Management method, which supports entrepreneurs in the creation and execution of future-focused strategies.

  11. Strengthening Concurrent Enrollment through NACEP Accreditation

    Science.gov (United States)

    Scheffel, Kent; McLemore, Yvette; Lowe, Adam

    2015-01-01

    This chapter describes how implementing the National Alliance of Concurrent Enrollment Partnerships' 17 accreditation standards strengthens a concurrent enrollment program, enhances secondary-postsecondary relations, and benefits students, their families, and secondary and postsecondary institutions.

  12. 78 FR 38053 - Regulatory Systems Strengthening

    Science.gov (United States)

    2013-06-25

    ... supply chain; risk assessment, analysis, and management; and emergency response. WHO helps to strengthen... in the world within increasingly complex supply chains. As national and global health programs work...; laboratory capacity; inspection and surveillance of products throughout the supply chain;...

  13. Mechanisms for slow strengthening in granular materials

    Science.gov (United States)

    Losert; Geminard; Nasuno; Gollub

    2000-04-01

    Several mechanisms cause a granular material to strengthen over time at low applied stress. The strength is determined from the maximum frictional force F(max) experienced by a shearing plate in contact with wet or dry granular material after the layer has been at rest for a waiting time tau. The layer strength increases roughly logarithmically with tau only if a shear stress is applied during the waiting time. The mechanisms of strengthening are investigated by sensitive displacement measurements, and by imaging of particle motion in the shear zone. Granular matter can strengthen due to a slow shift in the particle arrangement under shear stress. Humidity also leads to strengthening, but is found not to be its sole cause. In addition to these time dependent effects, the static friction coefficient can also be increased by compaction of the granular material under some circumstances, and by a cycling of the applied shear stress. PMID:11088198

  14. Experimental behavior of FRP strengthened masonry arches

    OpenAIRE

    Oliveira, Daniel V.; Basílio, Ismael; Lourenço, Paulo B.

    2010-01-01

    This paper deals with the experimental behavior of solid clay brick masonry arches strengthened with glass fiber reinforced polymer composites. Twelve half-scaled segmental masonry arches subjected to a load applied at the quarter span were tested under displacement control up to failure. The arches were built using handmade low strength bricks and a commercial lime-based mortar, trying to mimic ancient structures. Besides reference unreinforced arches, five different strengthening arrangemen...

  15. Strengthening health systems by health sector reforms

    OpenAIRE

    Senkubuge, Flavia; Modisenyane, Moeketsi; Bishaw, Tewabech

    2014-01-01

    Background: The rising burden of disease and weak health systems are being compounded by the persistent economic downturn, re-emerging diseases, and violent conflicts. There is a growing recognition that the global health agenda needs to shift from an emphasis on disease-specific approaches to strengthening of health systems, including dealing with social, environmental, and economic determinants through multisectoral responses.Methods: A review and analysis of data on strengthening health se...

  16. Mechanisms for slow strengthening in granular materials

    OpenAIRE

    Losert, W.; Geminard, J. -C.; Nasuno, S.; Gollub, J. P.

    1999-01-01

    Several mechanisms cause a granular material to strengthen over time at low applied stress. The strength is determined from the maximum frictional force F_max experienced by a shearing plate in contact with wet or dry granular material after the layer has been at rest for a waiting time \\tau. The layer strength increases roughly logarithmically with \\tau -only- if a shear stress is applied during the waiting time. The mechanisms of strengthening are investigated by sensitive displacement meas...

  17. Wire bonding in microelectronics

    CERN Document Server

    Harman, George G

    2010-01-01

    Wire Bonding in Microelectronics, Third Edition, has been thoroughly revised to help you meet the challenges of today's small-scale and fine-pitch microelectronics. This authoritative guide covers every aspect of designing, manufacturing, and evaluating wire bonds engineered with cutting-edge techniques. In addition to gaining a full grasp of bonding technology, you'll learn how to create reliable bonds at exceedingly high yields, test wire bonds, solve common bonding problems, implement molecular cleaning methods, and much more. Coverage includes: Ultrasonic bonding systems and technologies, including high-frequency systems Bonding wire metallurgy and characteristics, including copper wire Wire bond testing Gold-aluminum intermetallic compounds and other interface reactions Gold and nickel-based bond pad plating materials and problems Cleaning to improve bondability and reliability Mechanical problems in wire bonding High-yield, fine-pitch, specialized-looping, soft-substrate, and extreme-temperature wire bo...

  18. Ultrasonic power features of wire bonding and thermosonic flip chip bonding in microelectronics packaging

    Institute of Scientific and Technical Information of China (English)

    LI Jun-hui; HAN Lei; ZHONG Jue

    2008-01-01

    The driving voltage and current signals of piezoeeramie transducer (PZT) were measured directly by designing circuits from ultrasonic generator and using a data acquisition software system. The input impedance and power of PZT were investigated by using root mean square (RMS) calculation. The vibration driven by high frequency was tested by laser Doppler vibrometer (PSV-400-M2). And the thermosonic bonding features were observed by scanning electron microscope (JSM-6360LV). The results show that the input power of bonding is lower than that of no load. The input impedance of bonding is greater than that of no load.Nonlinear phase, plastic flow and expansion period, and strengthening bonding process are shown in the impedance and power curves. The ultrasonic power is in direct proportion to the vibration displacement driven by the power, and greater displacements driven by high power (5W) result in welding failure phenomena, such as crack, break, and peeling off in wedge bonding. For thermosonic flip chip bonding, the high power decreases position precision of bonding or results in slippage and rotation phenomena of bumps. To improve reliability and precision of thermosonic bonding, the low ultrasonic power (about 1-5W) should be chosen.

  19. Self-Monitoring Strengthening System Based on Carbon Fiber Laminate

    Directory of Open Access Journals (Sweden)

    Rafal Krzywon

    2016-01-01

    Full Text Available Externally bonded composites reinforced with high-strength fibers are increasingly popular in construction, especially in structures’ strengthening, where the best possible mechanical properties are required. At the same time the ability to autodetect threats is one of the most desirable features of contemporary structures. The authors of the paper have developed an intelligent fabric, wherein the carbon fibers play the role of not only tensile reinforcement but also strain sensor. The idea is based on the construction of the strain gauge, where the thread of carbon fibers arranged in zig-zag pattern works as electrical conductor and is insulated by parallel thread of glass or acrylic fibers. Preliminary laboratory tests were designed to create effective measurement techniques and assess the effectiveness of the strengthening of selected building structures, as reinforced concrete and timber beams. Presented in the paper, selected results of these studies are very promising, although there were some noted problems to be considered in next steps. The main problem here is the control of the cross section of the fibers tow, affecting the total resistance of the fabric. One of the main deficiencies of the proposed solution is also sensitivity to moisture.

  20. Square concrete columns strengthened with carbon fiber reinforced plastics sheets at low temperatures

    Institute of Scientific and Technical Information of China (English)

    MA Qin-yong; LU Xiao-yu

    2009-01-01

    Twenty-one square concrete columns were constructed and tested. The testing results indicate that bonded carbon fiber reinforced plastics (CFRP) sheets can be used to increase the strength and improve the serviceability of damaged concrete columns at low temperatures. The failure of the specimens, in most cases, takes place within the middle half of the columns. And the failure of strengthened columns is sudden and explosive. The CFRP sheets increase both the axial load capacity and the ultimate concrete compressive strain of the columns. The ultimate loads of strengthened columns at -10, 0 and 10℃ increase averagely by 9.09%, 6.63% and 17.83%, respectively, as compared with those of the control specimens. The axial compressive strength of strengthened columns is related to the curing temperatures. The improvement of axial compressive strength decreases with reducing temperature, and when the temperature drops to a certain value, the improvement increases with falling temperature.

  1. Experimental study and analysis on fatigue stiffness of RC beams strengthened with CFRP and steel plate

    Institute of Scientific and Technical Information of China (English)

    LU Yi-yan; HU Ling; LI Shan; WANG Kang-hao

    2016-01-01

    The objective of this work is to investigate the fatigue behavior of reinforced concrete (RC) beams strengthened with externally bonded carbon fiber reinforced polymer (CFRP) and steel plate. An experimental investigation and theoretical analysis were made on the law of deflection development and stiffness degradation, as well as the influence of fatigue load ranges. Test results indicate that the law of three-stage change under fatigue loading is followed by both midspan deflection and permanent deflection, which also have positive correlation with fatigue load amplitude. Fatigue stiffness of composite strengthened beams degrades gradually with the increasing of number of cycles. Based on the experimental results, a theoretical model by effective moment of inertia method is developed for calculating the sectional stiffness of such composite strengthened beams under fatigue loading, and the calculated results are in good agreement with the experimental results.

  2. Durability of reinforced concrete beams strengthened with fiber reinforced polymers under varying environmental conditions

    International Nuclear Information System (INIS)

    Fiber reinforced polymers (FRP) materials were adopted by the aerospace and marine industries, not only for their lightweight and high strength characteristics but also due to their tough and durable nature . As the engineering community has become more familiar with the performance advantages of these materials, new applications have been investigated and implemented. Researches and design guidelines concluded that externally bonded FRP to concrete elements could efficiently increase the capacity of RC elements. Long-term exposure to harsh environments deteriorates concrete and the need for repair and rehabilitation is evident. In order to accept these FRP materials, they must be evaluated for durability in harsh environments. An experimental program was conducted at the materials laboratory- faculty of engineering-Ain Shams university to study the durability of RC beams strengthened with FRP sheets and to compare them with un strengthened beams.The effect of gamma rays on FRP materials and concrete specimens bonded to FRP sheets were also investigated.

  3. On Bond Portfolio Management

    OpenAIRE

    Vladislav Kargin

    2002-01-01

    This paper describes a new method of bond portfolio optimization based on stochastic string models of correlation structure in bond returns. The paper shows how to approximate correlation function of bond returns, compute the optimal portfolio allocation using Wiener-Hopf factorization, and check whether a collection of bonds presents arbitrage opportunities.

  4. Shear strengthening of pre-damaged reinforced concrete beams with carbon fiber reinforced polymer sheet strips

    Institute of Scientific and Technical Information of China (English)

    Feras ALZOUBI; ZHANG Qi; LI Zheng-liang

    2007-01-01

    This paper presents the results of an experimental investigation on the response of pre-damaged reinforced concrete (RC) beam strengthened in shear using applied-epoxy unidirectional carbon fiber reinforced polymer (CFRP) sheet. The reasearch included four test rectangular simply supported RC beams in shear capacity. One is the control beam, two RC beams are damaged to a predetermined degree from ultimate shear capacity of the control beam, and the last beam is left without pre-damaged and then strengthened with using externally bonded carbon fiber reinforced polymer to upgrade their shear capacity. We focused on the damage degree to beams during strengthening, therefore, only the beams with side-bonded CFRPs strips and horizontal anchored strips were used. The results show the feasibility of using CFRPs to restore or increase the load-carrying capacity in the shear of damaged RC beams. The failure mode of all the CFRP-strengthened beams is debonding of CFRP vertical strips. Two prediction available models in ACI-440 and fib European code were compared with the experimental results.

  5. Strengthened safeguards: Present and future challenges

    International Nuclear Information System (INIS)

    Full text: The safeguards system is experiencing what has been seen as a revolution and, in doing so, it is confronting a series of challenges. These can be grouped into three areas. Drawing and maintaining safeguards conclusions - The process by which the safeguards conclusions are derived is based upon the analysis, evaluation and review of all the information available to the Agency. This process is on- going, but the State Evaluation Reports are compiled and reviewed periodically. For States with an additional protocol in force, the absence of indicators of the presence of undeclared nuclear material or activities provides the basis for the safeguards conclusion. Future challenges center on States' expectations of, and reactions to, the results of the evaluation and review process. Designing and implementing integrated safeguards - The conceptual framework of integrated safeguards is being actively pursued. Basic principles have been defined and integrated safeguards approaches have been developed for various types of facilities. Work is also progressing on the design of integrated safeguards approaches for specific States. Complementary access is being successfully implemented, and procedures for the use of unannounced inspections are being developed with the prospect of cost- effectiveness gains. Costs neutrality vs. quality and credibility - The Department faces serious staff and financial challenges. It has succeeded so far in 'doing more' and 'doing better' within a zero-real growth budget, but the scope for further significant efficiency gains is exhausted. There is no capacity to absorb new or unexpected tasks. Difficulties in recruiting and retaining qualified and experienced staff exacerbate the problems and add to costs. The Director General of the IAEA has referred to the need for new initiatives to bridge the budgetary gap; a possible measure is proposed. The tasks of meeting the challenges and demands of strengthened safeguards have been added to

  6. Multicenter bonds, bond valence and bond charge apportion

    International Nuclear Information System (INIS)

    In the same way that the valence of an atom issues from the definition of bond index, we shoe here that the three-center bond index lends itself to the definition of a bond valence. Within the charge of a bond, we show that its self-charge (i.e., the amount of electron kept by the atoms involved in the bond) is parted in a such a way that the more electronegative atom tends to allot more electronic charge than the other atom. We give examples of these quantities and discuss the results for different kinds of chemical systems. We also show some results for four-center indices and report six-center indices for hexagonal rings. (author). 54 refs., 4 figs., 8 tabs

  7. Shear Strengthening of RC Beams Using Sprayed Glass Fiber Reinforced Polymer

    Directory of Open Access Journals (Sweden)

    Sayed Mohamad Soleimani

    2012-01-01

    Full Text Available The effectiveness of externally bonded sprayed glass fiber reinforced polymer (Sprayed GFRP in shear strengthening of RC beams under quasi-static loading is investigated. Different techniques were utilized to enhance the bond between concrete and Sprayed GFRP, involving the use of through bolts and nuts paired with concrete surface preparation through sandblasting and through the use of a pneumatic chisel prior to Sprayed GFRP application. It was found that roughening the concrete surface using a pneumatic chisel and using through bolts and nuts were the most effective techniques. Also, Sprayed GFRP applied on 3 sides (U-shaped was found to be more effective than 2-sided Sprayed GFRP in shear strengthening. Sprayed GFRP increased the shear load-carrying capacity and energy absorption capacities of RC beams. It was found that the load-carrying capacity of strengthened RC beams was related to an effective strain of applied Sprayed GFRP. This strain was related to Sprayed GFRP configuration and the technique used to enhance the concrete-FRP bond. Finally, an equation was proposed to calculate the contribution of Sprayed GFRP in the shear strength of an RC beam.

  8. Study on shear strengthening of RC continuous T-beams using different layers of CFRP strips

    Science.gov (United States)

    Alferjani, M. B. S.; Samad, A. A. Abdul; Elrawaff, Blkasem S.; Elzaroug, Omer; Mohamad, Noridah

    2015-05-01

    Carbon fiber reinforced polymer (CFRP) laminates are externally bonded to reinforced concrete (RC) members to provide additional strength such as flexural, shear, etc. However, this paper presents the results of an experimental investigation for enhancing the shear capacity of reinforced concrete (RC) continuous T- beams using different layers of CFRP wrapping schemes. A total of three concrete beams were tested and various sheet configurations and layouts were studied to determine their effects on ultimate shear strength and shear capacity of the beams. One beam was kept as control beams, while other beams were strengthened with externally bonded CFRP strips with three side bonding and one or two layers of CFRP strips. From the test results, it was found that all schemes were found to be effective in enhancing the shear strength of RC beams. It was observed that the strength increases with the number of sheet layers provided the most effective strengthening for RC continuous T- beam. Beam strengthened using this scheme showed 23.21% increase in shear capacity as compared to the control beam. Two prediction models available in literature were used for computing the contribution of CFRP strips and compared with the experimental results.

  9. Study on shear strengthening of RC continuous T-beams using different layers of CFRP strips

    International Nuclear Information System (INIS)

    Carbon fiber reinforced polymer (CFRP) laminates are externally bonded to reinforced concrete (RC) members to provide additional strength such as flexural, shear, etc. However, this paper presents the results of an experimental investigation for enhancing the shear capacity of reinforced concrete (RC) continuous T- beams using different layers of CFRP wrapping schemes. A total of three concrete beams were tested and various sheet configurations and layouts were studied to determine their effects on ultimate shear strength and shear capacity of the beams. One beam was kept as control beams, while other beams were strengthened with externally bonded CFRP strips with three side bonding and one or two layers of CFRP strips. From the test results, it was found that all schemes were found to be effective in enhancing the shear strength of RC beams. It was observed that the strength increases with the number of sheet layers provided the most effective strengthening for RC continuous T- beam. Beam strengthened using this scheme showed 23.21% increase in shear capacity as compared to the control beam. Two prediction models available in literature were used for computing the contribution of CFRP strips and compared with the experimental results

  10. Study on shear strengthening of RC continuous T-beams using different layers of CFRP strips

    Energy Technology Data Exchange (ETDEWEB)

    Alferjani, M. B. S.; Samad, A. A. Abdul; Mohamad, Noridah [Faculty of Civil and Environmental Engineering, Universiti Tun Hussein Onn Malaysia, Batu Pahat (Malaysia); Elrawaff, Blkasem S.; Elzaroug, Omer [Faculty of Civil Engineering Omar Al Mukhtar University, Bayda, Libya, Africa (Libya)

    2015-05-15

    Carbon fiber reinforced polymer (CFRP) laminates are externally bonded to reinforced concrete (RC) members to provide additional strength such as flexural, shear, etc. However, this paper presents the results of an experimental investigation for enhancing the shear capacity of reinforced concrete (RC) continuous T- beams using different layers of CFRP wrapping schemes. A total of three concrete beams were tested and various sheet configurations and layouts were studied to determine their effects on ultimate shear strength and shear capacity of the beams. One beam was kept as control beams, while other beams were strengthened with externally bonded CFRP strips with three side bonding and one or two layers of CFRP strips. From the test results, it was found that all schemes were found to be effective in enhancing the shear strength of RC beams. It was observed that the strength increases with the number of sheet layers provided the most effective strengthening for RC continuous T- beam. Beam strengthened using this scheme showed 23.21% increase in shear capacity as compared to the control beam. Two prediction models available in literature were used for computing the contribution of CFRP strips and compared with the experimental results.

  11. The Bonds That Remind Us: Maternal Reminiscing for Bonding Purposes in Relation to Children's Perceived Competence and Social Acceptance

    Science.gov (United States)

    Kulkofsky, Sarah; Behrens, Kazuko Y.; Battin, David B.

    2015-01-01

    The present study investigated the relation between characteristics of mother-child reminiscing and children's perceived competence and social acceptance. We focused specifically on conversations for bonding purposes (i.e., conversations that serve the function of maintaining or strengthening the relationship between the child and the mother) as…

  12. The basis for the strengthening of safeguards

    International Nuclear Information System (INIS)

    For the past 30 years, the International Atomic Energy Agency's safeguards system has contributed to the international non-proliferation regime, by providing, inter alia, assurances regarding the peaceful uses of declared nuclear material. However, the discovery of a clandestine nuclear weapons programme in Iraq in 1991 drew world-wide attention to the need to strengthen the system to address the absence of undeclared nuclear material and activities. Efforts to strengthen the IAEA's safeguards system began in 1991 and culminated in 1997 when the IAEA's Board of Governors approved a Model Protocol Additional to IAEA Safeguards Agreements which greatly expands the legal basis and scope of IAEA safeguards. Within this strengthened system it is expected that the IAEA be able to provide assurance not only of the absence of diversion of declared nuclear material but also on the absence of undeclared nuclear material and activities. This is to be done within a safeguards system that uses an optimal combination of all safeguards measures available, thereby achieving maximum effectiveness and efficiency within the available resources. This paper will summarize the evolution of the safeguards system, describe strengthened safeguards, report on the status of implementing the strengthening measures, and outline plans for integrating all available safeguards measures. (author)

  13. The Influence of CFRP Anchorage on Achieving Sectional Flexural Capacity of Strengthened Concrete Beams

    Directory of Open Access Journals (Sweden)

    Hayder A. Rasheed

    2015-12-01

    Full Text Available This research program is intended to verify the influence of using distributed external U-wrap CFRP anchorage to shift the failure mode from overall debonding to sectional flexural failure for concrete beams externally bonded with CFRP sheets. Premature cover delamination and FRP debonding are predominant failure modes in FRP flexural strengthening that may be delayed or prevented by using FRP anchorage. The present experimental study aims to comparatively prove that proper anchorage of flexural strengthening is anticipated to yield a classical flexural failure by FRP rupture or concrete crushing. Once the cohesion of concrete and/or the adhesion with the FRP is exhausted, the U-wraps are engaged to provide anchorage to the flexural FRP through shear friction. Accordingly, three identical T beams and three identical rectangular beams were designed and constructed to examine the capacity improvement by preventing premature debonding failure. The first specimen in each series was tested as a control beam. The second specimen in each series was strengthened using five layers of flexural CFRP in order to admit a debonding failure. The third specimen in each series was strengthened with the same five layers of flexural CFRP plus additional transverse CFRP U-wraps. This study proved that it is possible to quantify the higher flexural capacity of CFRP strengthened beams using external anchorage.

  14. 3D FE Analysis of RC Beams Externally Strengthened with SRG/SRP Systems

    Directory of Open Access Journals (Sweden)

    Francesco Bencardino

    2016-05-01

    Full Text Available The purpose of this study is to evaluate, through a nonlinear Finite Element (FE analysis, the structural behavior of Reinforced Concrete (RC beams externally strengthened by using Steel Reinforced Grout (SRG and Steel Reinforced Polymer (SRP systems. The parameters taken into account were the external strengthening configuration, with or without U-wrap end anchorages, as well as the strengthening materials. The numerical simulations were carried out by using a three-dimensional (3D FE model. The linear and nonlinear behavior of all materials was modeled by appropriate constitutive laws and the connection between concrete substrate and external reinforcing layer was simulated by means of cohesive surfaces with appropriate bond-slip laws. In order to overcome convergence difficulties, to simulate the quasi-static response of the strengthened RC beams, a dynamic approach was adopted. The numerical results in terms of load-displacement curves, failure modes, and load and strain values at critical stages were validated against some experimental data. As a result, the proposed 3D FE model can be used to predict the structural behavior up to ultimate stage of similar strengthened beams without carrying out experimental tests.

  15. Entre o fortalecimento e o declínio do vínculo voluntário-idoso dependente em um centro-dia Entre el fortalecimiento y la decadencia del vínculo voluntario-anciano dependiente en un centro-día Between the strengthening and the decline of the bond volunteer-disabled elderly person in a day-care center

    Directory of Open Access Journals (Sweden)

    Silvia Cristina Mangini Bocchi

    2010-12-01

    Interactionism as a theoretical framework and the Grounded Theory as a methodological background. It aimed at understanding the volunteer-disabled elderly person interaction at a Day-Care Center and at designing a representative theoretical model for such experience. Data were collected by non-directive interviews. Two phenomena emerged from data analysis: becoming responsible for the continuity of volunteer work with disabled elderly persons supported by the healing expectation of former family caregivers in a society with a declining solidary conscience and assuming the volunteer role. Understanding the experience enbaled us to expand the knowledge concerning the movement undertaken in the experience denominated: between strengthening and the decline of the bond volunteerdisabled elderly person in a day-care hospital, mediated by (de motivation.

  16. Capacidade resistente e modos de ruptura de vigas de concreto armado reforçadas à flexão com fibras de carbono Resistant capacity and failure modes of reinforced concrete beams strengthened in flexure with externally bonded carbon fiber reinforced plastic

    Directory of Open Access Journals (Sweden)

    Augusto Ottoni Bueno da Silva

    2012-09-01

    Full Text Available Para se projetar um reforço à flexão com material polimérico reforçado com fibras, em uma viga de concreto armado, é necessário que o engenheiro responsável opte por trabalhar sem a utilização de mecanismos de incremento de ancoragem, obviamente dentro de níveis seguros, ou utilize artifícios que lhe garantam alcançar a deformação última de projeto da fibra fornecida pelo fabricante da manta. Nesse artigo, é apresentada a base para o cálculo das duas metodologias, segundo os critérios mais expressivos existentes, e são feitas comparações com resultados experimentais. Para o reforço sem ancoragem, verificou-se que, para se evitarem as indesejadas rupturas prematuras e bruscas, as metodologias propostas pelos ACI e FIB mostraram-se adequadas. Para se garantir a deformação última da fibra, foi estudado um mecanismo com ancoragem lateral a 45° feito com o próprio material da fibra. Nesse caso, utilizou-se o processo de seções balanceadas, para a previsão do modo de ruptura, e, em seguida, foram feitas as devidas comparações entre os valores esperados com os resultados obtidos nos ensaios em laboratório.To design an externally bonded fiber reinforced plastic reinforcement for a reinforced concrete beam, it is necessary that the engineer responsible chooses to work without the use of mechanisms to increase the anchoring within safe levels, or make use of artifacts to ensure that the deformation in the fiber reaches ultimate state value supplied by the manufacturer. This article shows the basis for the calculation of the two methodologies under the existing criteria more expressively and also makes comparisons with laboratory tests. For enhancement without anchoring, it was found that to prevent unwanted premature and abrupt ruptures, the methods proposed by ACI and FIB showed to be adequate. To ensure the ultimate deformation of the fiber, a mechanism for anchoring in the form of a bow 45º made by the material of the

  17. Strengthening Nordic-Baltic Defense Capabilities

    DEFF Research Database (Denmark)

    Breitenbauch, Henrik Ø.

    2014-01-01

    troubling challenge to the way international security has been structured in Europe since the end of the Cold War. While most of the existing defense cooperation with a view of strengthening defense capabilities has been carried out within the internationally renowned framework of NORDEFCO, there is no...... reason why this framework could not be extended to the Baltic states.36 A NORBALDEFCO would not only cement the prominent role of Sweden and Finland within NATO as premier partners, it would also formally continue the work begun with Baltic independ- ence after the Cold War, and furthermore strengthen...

  18. Hydrogen bonded supramolecular structures

    CERN Document Server

    Li, Zhanting

    2015-01-01

    This book covers the advances in the studies of hydrogen-bonding-driven supramolecular systems  made over the past decade. It is divided into four parts, with the first introducing the basics of hydrogen bonding and important hydrogen bonding patterns in solution as well as in the solid state. The second part covers molecular recognition and supramolecular structures driven by hydrogen bonding. The third part introduces the formation of hollow and giant macrocycles directed by hydrogen bonding, while the last part summarizes hydrogen bonded supramolecular polymers. This book is designed to b

  19. Acrylic Rubber Latex in Ferrocement for Strengthening Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    D. R. Kumar

    2010-01-01

    Full Text Available Problem statement: In India, the early deterioration of reinforced concrete structures has become a big social problem in recent years. An essential research is needed for the development of effective repair materials and their execution systems comes to an important issue from the viewpoint of the longevity of infrastructures at present. Ferrocement laminates are introduced to enhance the overall performance of Reinforced Concrete (RC structures and these days the use of it is a promising technology for increasing the flexural strength of deficient reinforced concrete members. Approach: The repair system aims to provide quantitative repair enhancement as well as extending the life of deteriorated concrete members. This research in particular inspired the initiation of the present work which aimed to develop a material with unique properties and a very wide range of practical applications. The mechanical properties of mortar through difference in polymer content with Acrilic Latex by ferrocement among three different volume fractions of mesh reinforcement were studied. Following the encouraging progress made in the formulation and evaluation of the polymer modified repair mortar, tests were carried out involving the application of the reinforced repair material to the soffit of the reinforced concrete beams of 3 m length. Results: The levels of damage of the original beams prior to repair did not affect the ultimate load of the strengthened beams tested. The performance of the strengthened beams was compared to the control beams with respect to cracking, deflection and ultimate strength which confirm preeminent results. Conclusion: This accomplished the fact that acrylic rubber latex modified ferrocement is a doable alternative strengthening component for the rehabilitation of reinforced concrete structures. Further developments in these systems will create dramatic improvement into the field of rehabilitation of old privileged structures.

  20. Applying principles of health system strengthening to eye care

    Directory of Open Access Journals (Sweden)

    Karl Blanchet

    2012-01-01

    Full Text Available Understanding Health systems have now become the priority focus of researchers and policy makers, who have progressively moved away from a project-centred perspectives. The new tendency is to facilitate a convergence between health system developers and disease-specific programme managers in terms of both thinking and action, and to reconcile both approaches: one focusing on integrated health systems and improving the health status of the population and the other aiming at improving access to health care. Eye care interventions particularly in developing countries have generally been vertically implemented (e.g. trachoma, cataract surgeries often with parallel organizational structures or specialised disease specific services. With the emergence of health system strengthening in health strategies and in the service delivery of interventions there is a need to clarify and examine inputs in terms governance, financing and management. This present paper aims to clarify key concepts in health system strengthening and describe the various components of the framework as applied in eye care interventions.

  1. Applying principles of health system strengthening to eye care

    Science.gov (United States)

    Blanchet, Karl; Patel, Daksha

    2012-01-01

    Understanding Health systems have now become the priority focus of researchers and policy makers, who have progressively moved away from a project-centred perspectives. The new tendency is to facilitate a convergence between health system developers and disease-specific programme managers in terms of both thinking and action, and to reconcile both approaches: one focusing on integrated health systems and improving the health status of the population and the other aiming at improving access to health care. Eye care interventions particularly in developing countries have generally been vertically implemented (e.g. trachoma, cataract surgeries) often with parallel organizational structures or specialised disease specific services. With the emergence of health system strengthening in health strategies and in the service delivery of interventions there is a need to clarify and examine inputs in terms governance, financing and management. This present paper aims to clarify key concepts in health system strengthening and describe the various components of the framework as applied in eye care interventions. PMID:22944762

  2. Structure and bonding in clusters

    International Nuclear Information System (INIS)

    We review here the recent progress made in the understanding of the electronic and atomic structure of small clusters of s-p bonded materials using the density functional molecular dynamics technique within the local density approximation. Starting with a brief description of the method, results are presented for alkali metal clusters, clusters of divalent metals such as Mg and Be which show a transition from van der Waals or weak chemical bonding to metallic behaviour as the cluster size grows and clusters of Al, Sn and Sb. In the case of semiconductors, we discuss results for Si, Ge and GaAs clusters. Clusters of other materials such as P, C, S, and Se are also briefly discussed. From these and other available results we suggest the possibility of unique structures for the magic clusters. (author). 69 refs, 7 figs, 1 tab

  3. EXPERIMENTAL INVESTIGATION ON THE EFFECT OF NATURAL TROPICAL WEATHER ON INTERFACIAL BONDING PERFORMANCE OF CFRP-CONCRETE BONDING SYSTEM

    Directory of Open Access Journals (Sweden)

    MOHD H. MOHD HASHIM

    2016-04-01

    Full Text Available The existing reinforced concrete structures may require rehabilitation and strengthening to overcome deficiencies due to defect and environmental deterioration. Fibre Reinforced Polymer (FRP-concrete bonding systems can provide solution for the deficiencies, but the durability of the bonded joint needs to be investigated for reliable structural performance. In this research the interfacial bonding behaviour of CFRP-concrete system under tropical climate exposure is main interest. A 300 mm concrete prism was bonded with CFRP plate on its two sides and exposed for 3, 6, and 9 months to laboratory environment, continuous natural weather, and wet-dry exposure in 3.5% saltwater solution at room and 40 °C temperature. The prisms were subjected to tension and compression load under bonding test to measure the strain and determine stress distribution and shear stress transfer behaviour. The results of the bonding test showed that load transfer was fairly linear and uniform at lower load level and changed to non-linear and non- uniform at higher load level. The force transfers causes the shear stress distribution being shifted along the bonded length. The combination of climate effects may have provided better curing of the bonded joints, but longer duration of exposure may be required to weaken the bond strength. Nevertheless, CFRP-concrete bonding system was only minimally affected under the tropical climate and salt solution.

  4. Strengthened Chernoff-type variance bounds

    OpenAIRE

    Afendras, G.; Papadatos, N.

    2014-01-01

    Let $X$ be an absolutely continuous random variable from the integrated Pearson family and assume that $X$ has finite moments of any order. Using some properties of the associated orthonormal polynomial system, we provide a class of strengthened Chernoff-type variance bounds.

  5. The "Drug Court Strengthening Families" Program.

    Science.gov (United States)

    Logan, TK; Leukefeld, Carl; Minton, Lisa; Abrahmson, Joanie; Hughes, Rebecca

    2001-01-01

    Children of Drug Court clients are at high-risk for substance abuse and other risk factors. This paper summarizes the results of a program needs assessment, process evaluation, and outcome evaluation from the Kentucky Drug Court Strengthening Families Pilot Program. Results indicated overall positive changes for families in the program.…

  6. Strengthening Family Practices for Latino Families

    Science.gov (United States)

    Chartier, Karen G.; Negroni, Lirio K.; Hesselbrock, Michie N.

    2010-01-01

    This study examined the effectiveness of a culturally adapted Strengthening Families Program (SFP) for Latinos to reduce risks for alcohol and drug use in children. Latino families, predominantly Puerto Rican, with a 9- to 12-year-old child and a parent(s) with a substance abuse problem participated in the study. Pre- and post-tests were conducted…

  7. Bonding silicones with epoxies

    Energy Technology Data Exchange (ETDEWEB)

    Tira, J.S.

    1980-01-01

    It is shown that silicones, both room temperature vulcanizing (RTV) and millable rubber (press cured) can be successfully bonded to other materials using plasma treatment and epoxy adhesives. The plasma treatment using dry air atmosphere increases the surface energy of the silicone and thus provides a lower water contact angle. This phenomenon allows the epoxy adhesive to wet the silicone surface and ultimately bond. Bond strengths are sufficiently high to result in failures in the silicone materials rather than the adhesive bond.

  8. Australia's Bond Home Bias

    OpenAIRE

    Mishra, Anil V; Umaru B. Conteh

    2014-01-01

    This paper constructs the float adjusted measure of home bias and explores the determinants of bond home bias by employing the International Monetary Fund's high quality dataset (2001 to 2009) on cross-border bond investment. The paper finds that Australian investors' prefer investing in countries with higher economic development and more developed bond markets. Exchange rate volatility appears to be an impediment for cross-border bond investment. Investors prefer investing in countries with ...

  9. Malaysia : Bond Market Development

    OpenAIRE

    International Monetary Fund; World Bank

    2013-01-01

    This paper pertains to the bond market development in Malaysia, and provides an overview of the market scenario in the country. Malaysia has been successful in developing the capital markets, particularly bond markets, in the recent past. Now, it faces the challenge of how to improve broader access and efficiency of the bond market. A high degree of investor concentration, dominated by gov...

  10. Chemical bond fundamental aspects of chemical bonding

    CERN Document Server

    Frenking, Gernot

    2014-01-01

    This is the perfect complement to ""Chemical Bonding - Across the Periodic Table"" by the same editors, who are two of the top scientists working on this topic, each with extensive experience and important connections within the community. The resulting book is a unique overview of the different approaches used for describing a chemical bond, including molecular-orbital based, valence-bond based, ELF, AIM and density-functional based methods. It takes into account the many developments that have taken place in the field over the past few decades due to the rapid advances in quantum chemica

  11. Experimental Study of the Flexural Behaviour of Damaged RC Beams Strengthened in Bending Moment Region with Basalt Fiber Reinforced Polymer (BFRP) Sheets

    OpenAIRE

    Akshay P. Gholkar; H. S. JADHAV

    2014-01-01

    This paper presents the flexural behaviour of basalt fiber reinforced polymer (BFRP) strengthened reinforced concrete (RC) beams. For flexural strengthening of reinforced concrete beams, total twenty-two beams were cast and tested over an effective span of 900 mm up to failure of the beam under two-point loading. The beams were designed as under-reinforced beams. The beams were bonded with BFRP sheets in single layer and double layers in the bending moment region at the bottom...

  12. Research progress on fiber-reinforced composite resin-bonded fixed partial denture%纤维增强复合树脂粘接桥的研究进展

    Institute of Scientific and Technical Information of China (English)

    邱海燕; 张倩

    2013-01-01

    Fiber-reinforced composite resin-bonded fixed partial denture is a minimally invasive fixed restorative treatment, with great application prospect in prosthodontics. Recently, investigation of the mechanical behaviors of fiber-reinforced composite resin bonded bridges draws more and more attention from domestic and foreign scholars. This paper summarizes the factors affecting the mechanical strength of fiber-reinforced resin-bonded bridges.%  纤维增强复合树脂粘接桥是一种微创伤修复技术,在口腔修复领域有较大的应用前景,其研究也越来越多。本文就增强树脂粘接桥纤维的位置和走向、纤维的排列、纤维的数量、纤维表面的处理、聚合体基质的吸水性、纤维与树脂基质的浸润性、纤维增强复合体与表层树脂之间的粘接强度等影响纤维增强树脂粘接桥强度的因素作一综述。

  13. Debonding damage analysis in composite-masonry strengthening systems with polymer- and mortar-based matrix by means of the acoustic emission technique

    Science.gov (United States)

    Verstrynge, E.; Wevers, M.; Ghiassi, B.; Lourenço, P. B.

    2016-01-01

    Different types of strengthening systems, based on fiber reinforced materials, are under investigation for external strengthening of historic masonry structures. A full characterization of the bond behavior and of the short- and long-term failure mechanisms is crucial to ensure effective design, compatibility with the historic substrate and durability of the strengthening solution. Therein, non-destructive techniques are essential for bond characterization, durability assessment and on-site condition monitoring. In this paper, the acoustic emission (AE) technique is evaluated for debonding characterization and localization on fiber reinforced polymer (FRP) and steel reinforced grout-strengthened clay bricks. Both types of strengthening systems are subjected to accelerated ageing tests under thermal cycles and to single-lap shear bond tests. During the reported experimental campaign, AE data from the accelerated ageing tests demonstrated the thermal incompatibility between brick and epoxy-bonded FRP composites, and debonding damage was successfully detected, characterized and located. In addition, a qualitative comparison is made with digital image correlation and infrared thermography, in view of efficient on-site debonding detection.

  14. Strengthening of the Cooperative Framework for ANENT

    International Nuclear Information System (INIS)

    The Asian Network for Education in Nuclear Technology (ANENT) was established in February 2004 to promote nuclear education and training in Asia. Initially ANENT member countries cooperated with 5 group activities encompassing broad areas. As of 2006, the cooperative framework was strengthened in a way to focus on web-based nuclear education and training for a period of several years to come. In this context, the Nuclear Training Center (NTC) of KAERI has contributed, in particular, to the development of the ANENT web-portal including a cyber platform, and making available relevant courses and materials on the web-portal. This paper discusses details of the strengthened cooperative framework in terms of NTC's effort for realizing web-based education and training through regional networking

  15. Grain boundary strengthening in austenitic nitrogen steels

    International Nuclear Information System (INIS)

    The effect of nitrogen and carbon on the strengthening of the austenitic steel Cr18Ni16Mn10 by grain boundaries is studied. It is established in accordance with previous results that contrary to carbon nitrogen increases the coefficient k in the Hall-Petch equation markedly. Because of a pronounced planar slip induced by nitrogen and the absence of any noticeable segregation of nitrogen atoms at the grain boundaries, nitrogen austenite presents an excellent object for testing different existing models of grain boundary strengthening (pile-up, grain boundary dislocation sources, work hardening theories). Based on the analysis of available data and measurements of interaction between nitrogen (carbon) atoms and dislocations it is shown that the nitrogen effect can be attributed to a strong blocking of dislocation sources in grains adjacent to those where the slip started. (orig.)

  16. Understanding backward design to strengthen curricular models.

    Science.gov (United States)

    Emory, Jan

    2014-01-01

    Nurse educators have responded to the call for transformation in education. Challenges remain in planning curricular implementation to facilitate understanding of essential content for student success on licensure examinations and in professional practice. The conceptual framework Backward Design (BD) can support and guide curriculum decisions. Using BD principles in conjunction with educational models can strengthen and improve curricula. This article defines and describes the BD process, and identifies reported benefits for nursing education. PMID:24743175

  17. Strengthening of structure using advanced composites

    OpenAIRE

    Recuero, A.; Miravete, A.

    1997-01-01

    [EN] Restoration, strengthening and rehabilitation of buildings becomes one of the more interesting aspects of the use of composites. Construction industry has not yet accepted the wide structural use of these new materials because it does not know the advantages of composites in comparison with traditional materials, such as concrete or steel. Proffesionals involved in design and construction are conservative and resist to changes. They require codes and specifications, ...

  18. Strengthening of HSLA steels by cool deformation

    OpenAIRE

    a Fatehi; Calvo Muñoz, Jessica; Elwazri, A. M.; Yue, S

    2010-01-01

    In microalloyed steels, the refinement of ferrite grains together with a controlled amount of precipitation has key roles in the mechanical properties improvement. Applying small amounts of deformation, at very low hot working temperatures (i.e. coiling temperature), in the ferrite region (i.e. cool deformation) has an appreciable strengthening effect via controlling the final microstructure of the steel. One of the microstructural effects is thought to be the much finer and more uniformly...

  19. Strengthening behavior of carbon/metal nanocomposites

    OpenAIRE

    Shin, S. E.; Choi, H. J.; Hwang, J. Y.; Bae, D. H.

    2015-01-01

    Nanocomposites reinforced with nano-scale reinforcements exhibit excellent mechanical properties with low volume fraction of the reinforcement. For instance, only an addition of 0.7 vol.% few-layer graphene (FLG) into the pure titanium shows strength of ~1.5 GPa, obviously much superior to that of the monolithic titanium. The strengthening efficiency of composites is determined by several factors such as reinforcement geometrical/spatial characteristics and interfacial features between the ma...

  20. Plasticity of oxide dispersion strengthened ferritic alloys

    International Nuclear Information System (INIS)

    The object of this work is to study the plasticity mechanisms of two oxide dispersion strengthened ferritic alloys, DT and DY. Microstructural characterisation has been performed on DT and DY alloys by optical, scanning and transmission electron microscopy. These materials, strengthened by an oxide dispersion, contain an intermetallic χ phase precipitated on grain boundaries. The χ phase, stable up to 900 deg, can be dissolved into the matrix by heat treatment beyond 1 000 deg. Between 20 and 700 deg, according to tensile tests, the DY alloy which is strengthened by a fine dispersion of yttria particles is more resistant and less ductile than DT alloy, strengthened by titanium oxides. Tensile tests performed at room temperature, in the chamber of a SEM, have shown that micro-cracking of the χ phase coincides with the first stage of the macroscopic yielding. The cavities initiated by the χ phase micro-cracking induce a ductile fracture of the matrix. A dynamic strain ageing mechanism has been observed around 400 deg, which is attributed to the Mo contribution. Between 20 and 700 deg, comparison of tensile properties of alloys with or without χ phase has shown that the intermetallic phase has a detrimental effect on the ductility, but has no influence on the mechanical strength. Creep tests have been performed between 500 and 700 deg. Thermally activated plasticity mechanisms are observed in this temperature range. The χ phase, which is always micro-cracked after tensile testing, is not damaged after creep testing below a critical stress. This behaviour is explained by the influence of strain rate through the competition between strain hardening and relaxation of the matrix. (author)

  1. Collection of "strengthening sets" of aerobics lesson.\\\\

    OpenAIRE

    CAKL, Vojtěch

    2011-01-01

    The aim of this bachelor study was to create a strengthening sets for aerobic lessons including showing these possisions in practice on selective aerobic lessons . Based on special literature the author had chosen suitable muscle development exercises to increase the body strenth. These exercises were there practised for six weeks continuously. Before and after the research were selected individuals who were compared by 4 exact same tests to detect static and dynamic body strength. The result...

  2. Strengthening the non proliferation regime: French views

    International Nuclear Information System (INIS)

    3 main issues can be identified in the French policy concerning the backing of non proliferation: 1) responding resolutely to proliferation crises, 2) reinforcing substantive efforts to prevent and impede proliferation, and 3) strengthening the non-proliferation regime. The first issue is very important because combating proliferation is vital to the security of all. Concerning the second issue, France attaches particular importance to strengthening specific measures to prevent and check proliferation. Let me mention a few proposals that we put forward: exports need to be controlled more effectively, proliferation activities have to be criminalized, or the development of proliferation-resistant technologies should be supported. Concerning the third issue it means the strengthening of the non-proliferation regime, France proposes several means: -) aiming at the universalization of the additional protocol; -) ensuring that the Agency continues to have sufficient human, financial and technical resources to fulfill its verification mission effectively; -) encouraging the IAEA to make full use of the authority available to it; -) enhancing the use of information relevant to the delivery of the IAEA mandate; and -) sharing more accurate information concerning the breaches of commitments that happen. The paper is followed by the slides of the presentation. (A.C.)

  3. Information analysis in the strengthened safeguards system

    International Nuclear Information System (INIS)

    Full text: The changing political framework of the early 1990s revealed the limitations of traditional Safeguards and led the Member States to strengthen Safeguards. This was done under a two- pronged approach: while Programme 93+2 developed the model Additional Protocol (INFCIRC/540), which would require an expanded declaration, complementary access, and broader environmental sampling, the Safeguards measures in force under the existing comprehensive Safeguards Agreements were strengthened through voluntary reporting, environmental sampling, and enhanced information analysis. The purpose of both of these initiatives was to broaden the mission of the IAEA to include the detection of undeclared nuclear material and activities. The effect was to increase dramatically the amount of information available to the Agency and the challenge was to develop a method and infrastructure to evaluate all this information. Since 1992 the Agency has developed a state evaluation process for collecting, organizing, and analyzing new types of information (open source information, the results of environmental sampling, commercial satellite imagery) and integrating this information with the familiar state declared and verification information traditionally collected and evaluated by the Agency. This address will describe the components and challenges of information analysis under strengthened Safeguards, the heart of the state evaluation process. (author)

  4. Self-diagnosis of structures strengthened with hybrid carbon-fiber-reinforced polymer sheets

    Science.gov (United States)

    Wu, Z. S.; Yang, C. Q.; Harada, T.; Ye, L. P.

    2005-06-01

    The correlation of mechanical and electrical properties of concrete beams strengthened with hybrid carbon-fiber-reinforced polymer (HCFRP) sheets is studied in this paper. Two types of concrete beams, with and without reinforcing bars, are strengthened with externally bonded HCFRP sheets, which have a self-structural health monitoring function due to the electrical conduction and piezoresistivity of carbon fibers. Parameters investigated include the volume fractions and types of carbon fibers. According to the investigation, it is found that the hybridization of uniaxial HCFRP sheets with several different types of carbon fibers is a viable method for enhancing the mechanical properties and obtaining a built-in damage detection function for concrete structures. The changes in electrical resistance during low strain ranges before the rupture of carbon fibers are generally smaller than 1%. Nevertheless, after the gradual ruptures of carbon fibers, the electrical resistance increases remarkably with the strain in a step-wise manner. For the specimens without reinforcing bars, the electrical behaviors are not stable, especially during the low strain ranges. However, the electrical behaviors of the specimens with reinforcing bars are relatively stable, and the whole range of self-sensing function of the HCFRP-strengthened RC structures has realized the conceptual design of the HCFRP sensing models and is confirmed by the experimental investigations. The relationships between the strain/load and the change in electrical resistance show the potential self-monitoring capacity of HCFRP reinforcements used for strengthening concrete structures.

  5. RC beams shear-strengthened with fabric-reinforced-cementitious-matrix (FRCM) composite

    Science.gov (United States)

    Loreto, Giovanni; Babaeidarabad, Saman; Leardini, Lorenzo; Nanni, Antonio

    2015-12-01

    The interest in retrofit/rehabilitation of existing concrete structures has increased due to degradation and/or introduction of more stringent design requirements. Among the externally-bonded strengthening systems fiber-reinforced polymers is the most widely known technology. Despite its effectiveness as a material system, the presence of an organic binder has some drawbacks that could be addressed by using in its place a cementitious binder as in fabric-reinforced cementitious matrix (FRCM) systems. The purpose of this paper is to evaluate the behavior of reinforced concrete (RC) beams strengthened in shear with U-wraps made of FRCM. An extensive experimental program was undertaken in order to understand and characterize this composite when used as a strengthening system. The laboratory results demonstrate the technical viability of FRCM for shear strengthening of RC beams. Based on the experimental and analytical results, FRCM increases shear strength but not proportionally to the number of fabric plies installed. On the other hand, FRCM failure modes are related with a high consistency to the amount of external reinforcement applied. Design considerations based on the algorithms proposed by ACI guidelines are also provided.

  6. Near Surface Mounted Composites for Flexural Strengthening of Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Md. Akter Hosen

    2016-03-01

    Full Text Available Existing structural components require strengthening after a certain period of time due to increases in service loads, errors in design, mechanical damage, and the need to extend the service period. Externally-bonded reinforcement (EBR and near-surface mounted (NSM reinforcement are two preferred strengthening approach. This paper presents a NSM technique incorporating NSM composites, namely steel and carbon fiber-reinforced polymer (CFRP bars, as reinforcement. Experimental and analytical studies carried out to explore the performance of reinforced concrete (RC members strengthened with the NSM composites. Analytical models were developed in predicting the maximum crack spacing and width, concrete cover separation failure loads, and deflection. A four-point bending test was applied on beams strengthened with different types and ratios of NSM reinforcement. The failure characteristics, yield, and ultimate capacities, deflection, strain, and cracking behavior of the beams were evaluated based on the experimental output. The test results indicate an increase in the cracking load of 69% and an increase in the ultimate load of 92% compared with the control beam. The predicted result from the analytical model shows good agreement with the experimental result, which ensures the competent implementation of the present NSM-steel and CFRP technique.

  7. Weak bond screening system

    Science.gov (United States)

    Chuang, S. Y.; Chang, F. H.; Bell, J. R.

    Consideration is given to the development of a weak bond screening system which is based on the utilization of a high power ultrasonic (HPU) technique. The instrumentation of the prototype bond strength screening system is described, and the adhesively bonded specimens used in the system developmental effort are detailed. Test results obtained from these specimens are presented in terms of bond strength and level of high power ultrasound irradiation. The following observations were made: (1) for Al/Al specimens, 2.6 sec of HPU irradiation will screen weak bond conditions due to improper preparation of bonding surfaces; (2) for composite/composite specimens, 2.0 sec of HPU irradiation will disrupt weak bonds due to under-cured conditions; (3) for Al honeycomb core with composite skin structure, 3.5 sec of HPU irradiation will disrupt weak bonds due to bad adhesive or oils contamination of bonding surfaces; and (4) for Nomex honeycomb with Al skin structure, 1.3 sec of HPU irradiation will disrupt weak bonds due to bad adhesive.

  8. The Feasibility of Modified Magnesia-Phosphate Cement as a Heat Resistant Adhesive for Strengthening Concrete with Carbon Sheets

    Directory of Open Access Journals (Sweden)

    Ailian Zhang

    2016-06-01

    Full Text Available External bonding of carbon fiber sheets has become a popular technique for strengthening concrete structures all over the world. Epoxy adhesive, which is used to bond the carbon fiber sheets and concrete, deteriorates rapidly when being exposed to high temperatures. This paper presents a high-temperature-resistant modified magnesia-phosphate cement (MPC with the compressive strength that does not decrease at the temperature of 600 °C. The bond properties of both the modified MPC and the epoxy adhesive between externally bonded carbon fiber sheets and concrete were evaluated by using a double-shear test method after exposure to elevating temperatures from 105 °C to 500 °C. The results showed that the bond strength of the modified MPC at room temperature (RT is much higher than that of the epoxy resin. Full carbonation with almost 0 MPa was detected for the epoxy sample after the exposure to 300 °C, while only 40% reduction of bond strength was tested for the modified MPC sample. Although the modified MPC specimens failed through interlaminar slip of fiber strips instead of complete debonding, the MPC specimens performed higher bond strength than epoxy resin at ambient temperature, and retained much higher bond strength at elevated temperatures. It could be concluded that it is feasible to strengthen concrete structural members with externally bonded carbon fiber sheets using the modified MPC instead of epoxy adhesive. Furthermore, the use of the modified MPC as the binder between carbon fiber sheets and concrete can be less expensive and an ecologically friendly alternative.

  9. Information analysis in the strengthened safeguards system

    International Nuclear Information System (INIS)

    Information Analysis is the heart of Strengthened Safeguards. The strengthened safeguards system is to detect the diversion of declared nuclear material and the presence of undeclared nuclear material and activities in a State with Comprehensive Safeguards agreements in force. In other words, under Strengthened Safeguards the Department of Safeguards must verify both the correctness and the completeness of State declarations concerning their nuclear inventories, facilities and activities. The changing political framework of the early 1990's, including such watershed events as the dissolution of the former Soviet Union, the information unearthed about the Iraqi weapon program, the declaration by South Africa of its past program, the resistance of the DPRK to verifying the completeness of its declarations, and the indefinite extension of the NPT, caused the IAEA Member States to demand stronger Safeguards and to accept the correspondingly more intrusive inspections and more complete declarations requirements. Two tracks were followed to strengthen safeguards under the 93 +2 Programme: additional measures were proposed under the existing authority of comprehensive safeguards agreements and still other measures were proposed which required the additional authority captured in a model Additional protocol (INFCIRC/540). Both types of additional measures required the Department to collect and process more information. Both types required new methods for integrating and evaluating this information. The new measures adopted under existing Comprehensive Safeguards Agreements included: voluntary reporting by States of the export of specified nuclear-related equipment and non-nuclear materials; collection and processing of environmental samples collected during inspections; remote monitoring of facilities and the use of unannounced inspections; acquisition of information from other Agency Departments; collection of publicly available, nuclear-related textual information from

  10. Hydrogen bonds in methane-water clusters.

    Science.gov (United States)

    Salazar-Cano, Juan-Ramón; Guevara-García, Alfredo; Vargas, Rubicelia; Restrepo, Albeiro; Garza, Jorge

    2016-08-24

    Characterization of hydrogen bonds in CH4-(H2O)12 clusters was carried out by using several quantum chemistry tools. An initial stochastic search provided around 2 500 000 candidate structures, then, using a convex-hull polygon criterion followed by gradient based optimization under the Kohn-Sham scheme, a total of 54 well defined local minima were located in the Potential Energy Surface. These structures were further analyzed through second-order many-body perturbation theory with an extended basis set at the MP2/6-311++G(d,p) level. Our analysis of Gibbs energies at several temperatures clearly suggests a structural preference toward compact water clusters interacting with the external methane molecule, instead of the more commonly known clathrate-like structures. This study shows that CH4-(H2O)12 clusters may be detected at temperatures up to 179 K, this finding provides strong support to a recently postulated hypothesis that suggests that methane-water clusters could be present in Mars at these conditions. Interestingly, we found that water to water hydrogen bonding is strengthened in the mixed clusters when compared to the isolated water dimer, which in turn leads to a weakening of the methane to water hydrogen bonding when compared to the CH4-(H2O) dimer. Finally, our evidence places a stern warning about the abilities of popular geometrical criteria to determine the existence of hydrogen bonds. PMID:27492605

  11. Collagen cross-linking: Strengthening the unstable cornea

    Directory of Open Access Journals (Sweden)

    Oren Tomkins

    2008-05-01

    Full Text Available Oren Tomkins, Hanna J GarzoziDepartment of Ophthalmology, Bnai Zion Medical Center, Haifa, IsraelAbstract: Corneal ectasia, a weakening of corneal integrity, occurs both due to acquired and congenital conditions such as keratoconus. It is a progressing condition that affects both visual acuity, and corneal stability. Various methods exist for correcting this impairment, however none address the inherit pathology, an increase laxity of the corneal stroma. Collagen crosslinking, a new, minimally invasive method, aims to strengthen the stroma by inducing cross links between neighboring collagen fibers. This method results in an increase in corneal tensile strength, with no medium term adverse effects on its normal architecture. Clinically, treated patients display improvement in both visual acuity and keratometric readings. This method may provide clinicians with easily accessible tools to stop the progression, and even correct visual deterioration due to corneal ectasia. Here we review the current information regarding this new method, as well as discuss its potential benefits and downfalls.Keywords: corneal cross-linking, corneal ectasia, keratoconus, stroma, cornea

  12. Expanded tenses in the old English orosius a syntactic strengthening*

    Directory of Open Access Journals (Sweden)

    Frančiška Trobevšek Drobnak

    2015-12-01

    Full Text Available The present chapter reports the investigation into certain aspects of the periphrastic construction to be +present participle (e.g. NE: "he is teaching"; OE. "he is laerende" viewed as an example of a syntactic strengthening. The construc­ tion is usually referred to as "continuous tenses/form" or "progressive tenses/form", whereas Nickel (1966 uses "expanded form". Coming closest to this latter term, the "expanded tenses" employed here seems a convenient label for two reasons: a  the use of expanded tenses is not restricted to the expression of verbal aspect (Aspekt or mode of verbal action (Aktionsart, which is implied by the use of either the term "continuous  tenses/form" or the term "progressive tenses/form"; b  the expanded tenses are integrated into the English tense system, in the sense that they can be substituted  with the respective non-expanded tenses without any change in the syntax of the clause, e.g.

  13. The Tension-Stiffening Contribution of NSM CFRP to the Behavior of Strengthened RC Beams

    Directory of Open Access Journals (Sweden)

    Ahmad Azim Shukri

    2015-07-01

    Full Text Available Tension stiffening is a characteristic behavior of reinforced concrete (RC beams which is directly affected by the bond-slip property of steel bar and concrete interfaces. A beam strengthened with a near-surface mounted (NSM technique would be even more affected by tension stiffening, as the NSM reinforcement also possess a bond-slip property. Yet assessing how much the tension stiffening of NSM contributes to the behavior of RC beams is difficult due to the fact that bond-slip effects cannot be directly incorporated into a strain-based moment-curvature analysis. As such, the tension stiffening is typically incorporated through various empirical formulations, which can require a great deal of testing and calibrations to be done. In this paper a relatively new method, which can be called the mechanics-based segmental approach, is used to directly simulate the tension stiffening effect of NSM reinforcements on RC beams, without the need for empirical formulations to indirectly simulate the tension stiffening. Analysis shows that the tension stiffening of NSM fiber reinforced polymer (FRP contributes a significant portion to the stiffness and strength of the strengthened RC beam not only during serviceability, but at all load levels.

  14. Consumption of carbon fiber plates in the reinforced concrete beams strengthened with CFPs

    Institute of Scientific and Technical Information of China (English)

    BU Liangtao; SONG Li; SHI Chuxian

    2007-01-01

    Four-point bending flexural tests were conducted to one full-size reinforced concrete (RC) beam and three full-size RC beams strengthened with carbon fiber plates (CFPs).The experimental results showed that the consumption of CFP had significant effects on failure modes and the flexural capacity.An analytical procedure,based on the limit failure ode and ductility,was presented to predict the applied area of CFP.An analytical program,based on Smith-Teng model and Cheng-Teng model,was provided to calculate the bonding length of CFP.The test results are used to validate the proposed procedure.The results are also applied to the design and construction of RC beam strengthened with CFP.

  15. Intermediate Crack Induced Debonding in Concrete Beams Strengthened with CFRP Plates - An Experimental Study

    DEFF Research Database (Denmark)

    Rusinowski, Piotr Michal; Täljsten, Björn

    2009-01-01

    , ductility and even durability. Design of structural strengthening applications using externally bonded FRP composites is usually based on conventional design approaches with improvement to account for the presence and characteristics of the FRP material. Non-conventional design issues that are specific to......FRP composites are becoming a material of choice in an increasing number of rehabilitation and retrofitting projects around the world. Depending on the design objectives, these materials can be used to improve one or more of the structural member characteristics, such as the load capacity...... strengthening method. End-peeling has governed a large interest and several debonding models have been presented. However, interfacial peeling at flexural cracks has not attained the same focus – even though this debonding failure is most likely more common. This paper presents laboratory tests of concrete...

  16. Intermediate Crack Induced Debonding in Concrete Beams Strengthened with CFRP Plates - An Experimental Study

    DEFF Research Database (Denmark)

    Rusinowski, Piotr Michal; Täljsten, Björn

    2009-01-01

    FRP composites are becoming a material of choice in an increasing number of rehabilitation and retrofitting projects around the world. Depending on the design objectives, these materials can be used to improve one or more of the structural member characteristics, such as the load capacity...... strengthening method. End-peeling has governed a large interest and several debonding models have been presented. However, interfacial peeling at flexural cracks has not attained the same focus – even though this debonding failure is most likely more common. This paper presents laboratory tests of concrete...... beams strengthened in flexure with CFRP epoxy bonded plates. Wrapping with CFRP sheets was applied in order to try to localize the failure initiation. Concrete cracking as well as debonding initiation and propagation was possible to observe with help of advanced optical measuring system and high speed...

  17. Method of producing an oxide dispersion strengthened coating and micro-channels

    Science.gov (United States)

    Kang, Bruce S; Chyu, Minking K; Alvin, Mary Anne; Gleeson, Brian M

    2013-12-17

    The disclosure provides a method for the production of composite particles utilizing a mechano chemical bonding process following by high energy ball milling on a powder mixture comprised of coating particles, first host particles, and second host particles. The composite particles formed have a grain size of less than one micron with grains generally characterized by a uniformly dispersed coating material and a mix of first material and second material intermetallics. The method disclosed is particularly useful for the fabrication of oxide dispersion strengthened coatings, for example using a powder mixture comprised of Y.sub.2O.sub.3, Cr, Ni, and Al. This particular powder mixture may be subjected to the MCB process for a period generally less than one hour following by high energy ball milling for a period as short as 2 hours. After application by cold spraying, the composite particles may be heat treated to generate an oxide-dispersion strengthened coating.

  18. Strengthening the Feeling of Identity and Self-esteem Through Group Music and Imagery

    DEFF Research Database (Denmark)

    Pedersen, Inge Nygaard

    understanding). I will present selected excerpts of the client´s processes such as the music they listen to, mandalas, narratives and their closing self reported outcome of the treatment. I will relate this to the theory model and show how strengthening of the feeling of identity and self-esteem through Group......This lecture is related to Lars Ole Bonde´s Keynote presentation, as we performed together several groups in the moderated GIM format of "Group Music and Imagery (GrpMI)" for psychiatric outpatients (adults) with a GAF score higher than 31 and with McGlashans´s Relational Level of Process higher...... than 4 in the years 2008-2010. I will present two case studies concerning two of the participants taking part in these group experiences. Focus will be on developments in the self-reported problem area of `strengthening the feeling of identity and self-esteem", which both clients shose among different...

  19. Study of solid solution strengthening of alloying element with phase structure factors

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Using the empirical electron theory of solids and molecules (EET), the phase structure factors, nA and nB, of the carbon-containing structural units with mass fraction of carbon (wC) below 0.8% and the mono-alloy structural units with wC at 0.2% in austenite and martensite are calculated. The solid solution strengthening brought by C-containing interstitial solid solution and alloy-substitutional solid solution in γ-Fe and α-Fe is discussed at electron structural level. The coefficient (s) of solid solution strengthening is advanced according to the bonding force between atoms. The study shows that when the criterion is applied to the carbonaceous or alloying element-containing solid solution the results of calculation will coincide with the experimental result very well.

  20. Bond Markets in Africa

    OpenAIRE

    Yibin Mu; Peter Phelps; Janet Gale Stotsky

    2013-01-01

    African bond markets have been steadily growing in recent years, but nonetheless remain undeveloped. African countries would benefit from greater access to financing and deeper financial markets. This paper compiles a unique set of data on corporate bond markets in Africa. It then applies an econometric model to analyze the key determinants of African government securities market and corporate bond market capitalization. Government securities market capitalization is directly related to bette...

  1. Build America Bonds

    OpenAIRE

    Andrew Ang; Vineer Bhansali; Yuhang Xing

    2010-01-01

    Build America Bonds (BABs) are a new form of municipal financing introduced in 2009. Investors in BAB municipal bonds receive interest payments that are taxable, but issuers receive a subsidy from the U.S. Treasury. The BAB program has succeeded in lowering the cost of funding for state and local governments with BAB issuers obtaining finance 54 basis points lower, on average, compared to issuing regular municipal bonds. For institutional investors, BAB issue yields are 116 basis points highe...

  2. The Bond Market's q

    OpenAIRE

    Thomas Philippon

    2006-01-01

    I propose an implementation of the q-theory of investment using bond prices instead of equity prices. Credit risk makes corporate bond prices sensitive to future asset values, and q can be inferred from bond prices. The bond market's q performs much better than the usual measure in standard investment equations. With aggregate data, the fit is three times better, cash flows are driven out and the implied adjustment costs are reduced by more than an order of magnitude. The new measure also imp...

  3. Copper wire bonding

    CERN Document Server

    Chauhan, Preeti S; Zhong, ZhaoWei; Pecht, Michael G

    2014-01-01

    This critical volume provides an in-depth presentation of copper wire bonding technologies, processes and equipment, along with the economic benefits and risks.  Due to the increasing cost of materials used to make electronic components, the electronics industry has been rapidly moving from high cost gold to significantly lower cost copper as a wire bonding material.  However, copper wire bonding has several process and reliability concerns due to its material properties.  Copper Wire Bonding book lays out the challenges involved in replacing gold with copper as a wire bond material, and includes the bonding process changes—bond force, electric flame off, current and ultrasonic energy optimization, and bonding tools and equipment changes for first and second bond formation.  In addition, the bond–pad metallurgies and the use of bare and palladium-coated copper wires on aluminum are presented, and gold, nickel and palladium surface finishes are discussed.  The book also discusses best practices and re...

  4. Hydrogen bonding and anaesthesia

    Science.gov (United States)

    Sándorfy, C.

    2004-12-01

    General anaesthetics act by perturbing intermolecular associations without breaking or forming covalent bonds. These associations might be due to a variety of van der Waals interactions or hydrogen bonding. Neurotransmitters all contain OH or NH groups, which are prone to form hydrogen bonds with those of the neurotransmitter receptors. These could be perturbed by anaesthetics. Aromatic rings in amino acids can act as weak hydrogen bond acceptors. On the other hand the acidic hydrogen in halothane type anaesthetics are weak proton donors. These two facts together lead to a probable mechanism of action for all general anaesthetics.

  5. Modelling of spreading process: effect from hydrogen bonds

    Institute of Scientific and Technical Information of China (English)

    Li Xin; Hu Yuan-Zhong; Jiang Lan

    2008-01-01

    Lubricant spreading on solid substrates has drawn considerable attention not only for the microscopic wetting theory but also for the dramatic application in head-disk interface of magnetic storage drive systems. Molecular dynamic simulation based on a coarse-grained bead-spring model has been used to study such a spreading process.The spreading profiles indicate that the hydrogen bonds among lubricant molecules and the hydrogen bonds between lubricant molecules and polar atoms of solid substrates will complicate the spreading process in a tremendous degree.The hydrogen bonds among lubricant molecules will strengthen the lubricant combination intensity, which may hinder most molecules from flowing down to the substrates and diffusing along the substrates. And the hydrogen bonds between lubricant molecules and polar atoms of solid substrates will confine the lubricant molecules around polar atoms, which may hinder the molecules from diffusing along the substrates and cause precursor film to vanish.

  6. Modelling of spreading process: effect from hydrogen bonds

    International Nuclear Information System (INIS)

    Lubricant spreading on solid substrates has drawn considerable attention not only for the microscopic wetting theory but also for the dramatic application in head-disk interface of magnetic storage drive systems. Molecular dynamic simulation based on a coarse-grained bead-spring model has been used to study such a spreading process. The spreading profiles indicate that the hydrogen bonds among lubricant molecules and the hydrogen bonds between lubricant molecules and polar atoms of solid substrates will complicate the spreading process in a tremendous degree. The hydrogen bonds among lubricant molecules will strengthen the lubricant combination intensity, which may hinder most molecules from flowing down to the substrates and diffusing along the substrates. And the hydrogen bonds between lubricant molecules and polar atoms of solid substrates will confine the lubricant molecules around polar atoms, which may hinder the molecules from diffusing along the substrates and cause precursor film to vanish. (condensed matter: structure, mechanical and thermal properties)

  7. Strengthening Public Financial Management in Postconflict Countries

    OpenAIRE

    Fritz, Verena; Hedger, Edward; Fialho Lopes, Ana Paula

    2011-01-01

    Understanding how to rebuild resilient states in post-conflict countries is an urgent priority for the international community. A new cross-country study of public financial management reforms in post-conflict situations shows that substantial progress is possible even in difficult circumstances, while showing a pattern of sequencing and progress that differs from standard assumptions. How...

  8. Bond characterization between concrete substrate and repairing SFRC using pull-off testing

    OpenAIRE

    Bonaldo, Everaldo; Barros, Joaquim A. O.; Lourenço, Paulo B.

    2005-01-01

    In the last years, an emerging repair and strengthening technique for concrete slabs has been used, consisting of applying a thin layer of steel fibre reinforced concrete(SFRC) onto the slabs. The performance of the strengthened structural system depends on the bonding behaviour between old and new concretes. Adhesives based on epoxy resins currently make this liaison. The prices of these adhesives are quite different depending, mainly, on the percentage of pure resin that they include. In...

  9. Gold's monetary roll will be strengthened - Plumbridge

    International Nuclear Information System (INIS)

    Delivering his Presidential address at the Chamber's annual general meeting, Mr Plumbridge said the gold market would enter a new phase and listed seven reasons why gold's monetary role would be strengthened. There was a dramatic increase in the demand for gold jewellery. He also forecasted that South African uranium production would again attain its former peak annual production of about 6000t. There is an essential need for a sustained growth in nuclear power and the prospects for uranium mining industry remain encouraging

  10. Antenatal care strengthening in jimma, ethiopia

    DEFF Research Database (Denmark)

    Villadsen, Sarah Fredsted; Tersbøl, Britt Pinkowski; Negussie, Dereje;

    2014-01-01

    Objective. We assessed how health system priorities matched user expectations and what the needs for antenatal care (ANC) strengthening were for improved maternal health in Jimma, Ethiopia. Methods. A questionnaire survey among all recent mothers in the study area was conducted to study the content...... of ANC and to identify the predictors of low ANC satisfaction. Further, a qualitative approach was applied to understand perceptions, practices, and policies of ANC. Results. There were no national guidelines for ANC in Ethiopia. Within the health system, the teaching of health professional students...

  11. Comparison of Gold Bonding with Mercury Bonding

    NARCIS (Netherlands)

    Kraka, Elfi; Filatov, Michael; Cremer, Dieter

    2009-01-01

    Nine AuX molecules (X = H, O, S, Se, Te, F, Cl, Br, I), their isoelectronic HgX(+) analogues, and the corresponding neutral HgX diatomics have been investigated using NESC (Normalized Elimination of the Small Component) and B3LYP theory to determine relativistic effects for bond dissociation energie

  12. Calculation of diagonal section and cross-section bending capacity for strengthening RC structure using high-performance ferrocement laminate

    Institute of Scientific and Technical Information of China (English)

    Shouping SHANG; Fangyuan ZHOU; Wei LIU

    2009-01-01

    Because there is a great demand of reinforce-ment and retrofitting of aged structures nationwide, as well as the rapid development of innovative building materials,the adoption of strengthening RC structures using new inorganic materials has become possible. High-performance ferrocement laminate (HPFL) is an effective method of strengthening concrete structure. High-performance ferrocement laminate is a new type of inorganic material with the advantages such as high strength, small contraction, good bonding properties, etc.This paper introduces the formula of cross-section bending capacity for strengthening concrete beams with HPEL. A comparative analysis of experimental data, as well as the calculation of diagonal section bearing capacity of concrete members, is given.

  13. Anchorage Failure of RC beams strengthened with FRP at the bottom face

    DEFF Research Database (Denmark)

    Täljsten, Björn; Arifovic, Fedja

    2009-01-01

    When RC beams are strengthened by FRP plates bonded to the bottom face of the beam they fail due to the lack of the mechanical anchorage of the plate. This paper shows that it is possible to relate the anchorage failure of tension face FRP-plated beams to the crack sliding capacity of the beams...... load of tension face plated beams. The assumption is that the FRP-plate must be extended at least one critical anchorage length beyond the theoretical occurrence of the critical diagonal crack....

  14. Coupled valence bond theory

    NARCIS (Netherlands)

    Havenith, R.W.A.

    2005-01-01

    In this Letter, the formulation and implementation of a parallel response property code for non-orthogonal, valence bond wave-functions are described. Test calculations on benzene and cyclobutadiene show that the polarisability and magnetisability tensors obtained using valence bond theory are compa

  15. Bonded labour in Pakistan

    OpenAIRE

    Ercelawn, Aly; Nauman, Muhammad

    2001-01-01

    Examines the continuing prevalence of debt bondage in the 1990s despite the introduction of national legislation banning the practice. Makes recommendations to the Government and the international community for actions to be taken to eliminate bonded labour and provide rehabilitation for freed workers. Includes texts of Land Reforms Regulations, 1972, the Sindh Tenancy Act, 1950 and the Bonded Labour System (Abolition) Act, 1992.

  16. The samurai bond market

    OpenAIRE

    Frank Packer; Elizabeth Reynolds

    1997-01-01

    Issuance in the samurai bond market has more than tripled over the past several years. Some observers have attributed this growth to a systematic underestimation of credit risk in the market. A detailed review of credit quality, ratings differences, and initial issue pricing in the samurai bond market, however, turns up little evidence to support this concern.

  17. Money and Nominal Bonds

    OpenAIRE

    Marchesiani, Alessandro; Senesi, Pietro

    2007-01-01

    This paper studies an economy with trading frictions, ex post heterogeneity and nominal bonds in a model à la Lagos and Wright (2005). It is shown that a strictly positive interest rate is a sufficient condition for the allocation with nominal bonds to be welfare improving. This result comes from the protection against the inflation tax.

  18. Hydrogen bonding in polyanilines

    Energy Technology Data Exchange (ETDEWEB)

    Bahceci, S. (Department of Chemistry, Middle East Technical University, Ankara 06531 (Turkey)); Toppare, L. (Department of Chemistry, Middle East Technical University, Ankara 06531 (Turkey)); Yurtsever, E. (Department of Chemistry, Middle East Technical University, Ankara 06531 (Turkey))

    1994-11-29

    Hydrogen bonding between poly(bisphenol A carbonate) (PC) and polyaniline (PAn) is analyzed using semi-empirical quantum methodology. Fully optimized AM1 molecular orbital calculations are reported for various aniline structures (monomer, dimer and trimer), the monomer of the PC and the hydrogen-bonded model of PAn-PC oligomer. ((orig.))

  19. Bonding stress-slip constitutive behavior between bars and grout concrete

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yi; LIU Ming; ZHOU Jing-hai; WANG Bing

    2009-01-01

    To establish bonding stress--slip constitutive model between bars and grout concrete, 13 test specimens were employed to study the bonding behavior and the force transfer of bars adhered to grout concrete. The bonding stress development of bars adhered to grout concrete was analyzed. The local bonding stress--slip curve was obtained. Based on the test results, a new bonding stress--slip constitutive model between bars and grout concrete was proposed. The results show that the maximum bonding stress is not influenced by the bar bond length, but it is strengthened when the splitting strength of grout concrete is increased. The model matches the experimental results well, and the regressing coefficient equals 1.7.

  20. Shape Bonding method

    Science.gov (United States)

    Pontius, James T. (Inventor)

    2010-01-01

    The present invention is directed to a method of bonding at least two surfaces together. The methods step of the present invention include applying a strip of adhesive to a first surface along a predefined outer boundary of a bond area and thereby defining a remaining open area there within. A second surface, or gusset plate, is affixed onto the adhesive before the adhesive cures. The strip of adhesive is allowed to cure and then a second amount of adhesive is applied to cover the remaining open area and substantially fill a void between said first and second surfaces about said bond area. A stencil may be used to precisely apply the strip of adhesive. When the strip cures, it acts as a dam to prevent overflow of the subsequent application of adhesive to undesired areas. The method results in a precise bond area free of undesired shapes and of a preferred profile which eliminate the drawbacks of the prior art bonds.

  1. Water's Hydrogen Bond Strength

    CERN Document Server

    Chaplin, Martin

    2007-01-01

    Water is necessary both for the evolution of life and its continuance. It possesses particular properties that cannot be found in other materials and that are required for life-giving processes. These properties are brought about by the hydrogen bonded environment particularly evident in liquid water. Each liquid water molecule is involved in about four hydrogen bonds with strengths considerably less than covalent bonds but considerably greater than the natural thermal energy. These hydrogen bonds are roughly tetrahedrally arranged such that when strongly formed the local clustering expands, decreasing the density. Such low density structuring naturally occurs at low and supercooled temperatures and gives rise to many physical and chemical properties that evidence the particular uniqueness of liquid water. If aqueous hydrogen bonds were actually somewhat stronger then water would behave similar to a glass, whereas if they were weaker then water would be a gas and only exist as a liquid at sub-zero temperature...

  2. Health metrics and evaluation: strengthening the science.

    Science.gov (United States)

    Murray, Christopher J L; Frenk, Julio

    2008-04-01

    With the growing importance of health in the global agenda comes the responsibility to develop a scientific foundation of metrics and evaluation. The scope of this emerging field can be viewed in terms of key topics, including health outcomes, other social outcomes related to health systems, health services, resource inputs, evaluations of programmes and systems, and analyses to support policy choice. It can also be defined in terms of key activities that are needed to strengthen the scientific basis of the field: development of new methods, instruments, software, and hardware; setting global norms and standards for data collection; increasing the availability of high-quality primary data; systematic analysis and synthesis of existing datasets; strengthening national capacity to obtain, analyse, and use data; and reporting and disseminating results. We explore in depth topics with major scientific challenges and institutional and cultural barriers that are slowing the development of the field. Cutting across the various topical areas and disciplinary approaches to these problems are some common scientific issues, including limited comparability of measurement, uncorrected known biases in data, no standard approach to missing data, unrealistic uncertainty estimates, and the use of disease models that have not been properly validated. Only through concerted action will it be possible to assure the production, reproduction, and use of knowledge that is crucial to the advancement of global health. PMID:18395581

  3. Strengthening the Canadian alcohol advertising regulatory system.

    Science.gov (United States)

    Heung, Carly M; Rempel, Benjamin; Krank, Marvin

    2012-01-01

    Research evidence points to harmful effects from alcohol advertising among children and youth. In particular, exposure to alcohol advertising has been associated with adolescents drinking both earlier and heavier. Although current federal and provincial guidelines have addressed advertising practices to prevent underage drinking, practice has not been supported by existing policy. While protective measures such as social marketing campaigns have the potential for counteracting the effects from alcohol advertising, the effectiveness of such measures can be easily drowned out with increasing advertising activities from the alcohol industry, especially without effective regulation. Research reviewed by the European Focus on Alcohol Safe Environment (FASE) Project has identified a set of key elements that are necessary to make alcohol advertising policy measures effective at protecting children and youth from the harmful effects of alcohol marketing. Using these key elements as an evaluation framework, there are critical components in the Canadian alcohol advertising regulatory system that clearly require strengthening. To protect impressionable children and youth against the harmful effects of alcohol advertising, 13 recommendations to strengthen current alcohol advertising regulations in Canada are provided for Canadian policy-makers, advertising standard agencies, and public health groups. PMID:23618638

  4. Carboxymethylated glucomannan as paper strengthening agent.

    Science.gov (United States)

    Wang, Meng; He, Weitao; Wang, Shun; Song, Xianliang

    2015-07-10

    Strength additives play an important role in allowing the papermaking industry to achieve its objectives. In this study, a new kind of paper strengthening agent based on glucomannan was developed by treating it with sodium chloroacetate under alkaline conditions, and the effects on paper properties were evaluated. Results indicated that carboxymethylated glucomannan could significantly improve the paper properties. Compared to the untreated paper, the density, burst index, tensile index, and folding endurance were increased by 15.2%, 22.8%, 34.6%, 179.0%, respectively, when 0.9% carboxymethylated glucomannan was used. Polyamide-epichlorohydrin (PAE) was used to improve the wet strength of the paper. When 0.6% PAE and 0.6% carboxymethylated glucomannan were used, the burst index, dry tensile index, wet tensile index of paper were increased by 14.1%, 25%, 34.3%, respectively, as compared to that of the control, while the folding endurance decreased slightly. In addition, dry tensile index and wet tensile index were increased with increasing the carboxymethylation time of glucomannan. The results demonstrated that PAE and carboxymethylated glucomannan displayed a synergistic effect. SEM analysis illustrated that paper strengthening agent could increase the combination of fibers in paper. PMID:25857990

  5. Strengthening the foundations of proliferation assessment tools.

    Energy Technology Data Exchange (ETDEWEB)

    Rexroth, Paul E.; Saltiel, David H.; Rochau, Gary Eugene; Cleary, Virginia D.; Ng, Selena (AREVA NC, Paris, France); Greneche, Dominique (AREVA NC, Paris, France); Giannangeli, Don (Texas A& M University, College Station, TX); Charlton, William S. (Texas A& M University, College Station, TX); Ford, David (Texas A& M University, College Station, TX)

    2007-09-01

    Robust and reliable quantitative proliferation assessment tools have the potential to contribute significantly to a strengthened nonproliferation regime and to the future deployment of nuclear fuel cycle technologies. Efforts to quantify proliferation resistance have thus far met with limited success due to the inherent subjectivity of the problem and interdependencies between attributes that lead to proliferation resistance. We suggest that these limitations flow substantially from weaknesses in the foundations of existing methodologies--the initial data inputs. In most existing methodologies, little consideration has been given to the utilization of varying types of inputs--particularly the mixing of subjective and objective data--or to identifying, understanding, and untangling relationships and dependencies between inputs. To address these concerns, a model set of inputs is suggested that could potentially be employed in multiple approaches. We present an input classification scheme and the initial results of testing for relationships between these inputs. We will discuss how classifying and testing the relationship between these inputs can help strengthen tools to assess the proliferation risk of nuclear fuel cycle processes, systems, and facilities.

  6. Strengthening under Load: Experimental and Numerical Research

    Science.gov (United States)

    Vild, M.; Bajer, M.

    2015-11-01

    The paper presents experimental and numerical research of strengthening of columns under load using welded plates. Three sets of three columns each were tested. All columns were 3 m long. The load from loading cylinders was transmitted through knife-edge bearings, which ensured pinned boundary condition perpendicular to the weaker axis. Set (A) comprised columns with welded T shaped cross-section. Set (B) comprised columns with welded monosymmetric I shaped cross-section. Both sets (A) and (B) had been loaded monotonically until collapse occurred. Set (C) contained columns with T shaped cross-section with the same dimensions as the columns in set (A). The columns from set (C) were first loaded to 70 kN. The force was being held constant and the second flange was being welded to the web under load. After the welding process was finished and the specimen cooled, the column was loaded to failure. The average forces at collapse of column sets (A), (B) and (C) were 143 kN, 308 kN and 323 kN, respectively. It was unexpected that the columns strengthened under load (C) had higher average resistance than the columns welded without preload (B). It could be caused by the residual stress and distortion caused by welding. The study includes the results of finite element models of the problem created in ANSYS software. The results from the experiments and numerical simulations were compared.

  7. Substructural strengthening in molybdenum and Mo-33Re

    International Nuclear Information System (INIS)

    Strengthening from defect substructures has been studied in Mo-33Re deformed in tension and by cold rolling, and in shock-loaded molybdenum and Mo-33Re. In cold-rolled and tensile-deformed Mo-33Re, strengthening arises from dislocation-dislocation interactions for smaller strains (less than 0.3), while at larger strains by rolling there is additional strengthening from dislocation cell formation and texture development. In shock-loaded molybdenum, dislocation-dislocation interactions are the primary source of strengthening, while in shock-loaded Mo-33Re dislocations and twin boundaries both contribute to strengthening. The coefficients for dislocation strengthening in both shock-loaded molybdenum and shock-loaded Mo-33Re are consistent with the values for the cold-rolled Mo-33Re and with published values for a wide range of other materials, indicating that the strengthening mechanism is similar for conventional and shock deformation. (Auth.)

  8. Progress in ODS Alloys: A Synopsis of a 2010 Workshop on Fe- Based ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kad, Bimal [University of California, San Diego; Dryepondt, Sebastien N [ORNL; Jones, Andy R. [University of Liverpool; Vito, Cedro III [National Energy Technology Laboratory (NETL); Tatlock, Gordon J [ORNL; Pint, Bruce A [ORNL; Tortorelli, Peter F [ORNL; Rawls, Patricia A. [National Energy Technology Laboratory (NETL)

    2012-01-01

    In Fall 2010, a workshop on the role and future of Fe-based Oxide Dispersion Strengthened (ODS) alloys gathered together ODS alloy suppliers, potential industrial end-users, and technical experts in relevant areas. Presentations and discussions focused on the current state of development of these alloys, their availability from commercial suppliers, past major evaluations of ODS alloy components in fossil and nuclear energy applications, and the technical and economic issues attendant to commercial use of ODS alloys. Significant progress has been achieved in joining ODS alloys, with creep resistant joints successfully made by inertia welding, friction stir welding and plasma-assisted pulse diffusion bonding, and in improving models for the prediction of lifetime components. New powder and alloy fabrication methods to lower cost or improve endproduct properties were also described. The final open discussion centered on challenges and pathways for further development and large-scale use of ODS alloys.

  9. Static and dynamic experimental study of strengthened reinforced short concrete corbel by using carbon fabrics, crack path in shear zone

    OpenAIRE

    I. Ivanova; J. Assih

    2015-01-01

    The paper presents an experimental analysis of tracking the path of the cracks and crack growth in strengthened or repair reinforced concrete short corbels bonded by carbon fiber fabrics under static and dynamic loads. The reinforced short concrete corbel is a used precast element, for industrial buildings and structures. In fact, their functioning interestingly unconventional is compared to classical beam type elements. Then the effects of bending and shearing are combined in ...

  10. Effect of CFRP Plate Location on Flexural Behavior of RC Beam Strengthened with CFRP Plate

    Directory of Open Access Journals (Sweden)

    Mohammed Jassam Mohammed Altaee

    2011-01-01

    Full Text Available Location of CFRP plate, as a mode of failure, is one of the major limitations when using externally bonded carbon fiber reinforced polymer (CFRP plates in strengthening of RC beams. In this work, mode of CFRP plate location was analytically investigated. A non-linear finite element model is proposed in order to analyze experimental data presented by David et.al.[1]. The eight node brick element (SOLID65 as denoted in ANSYS is used to model reinforced concrete and four node shell element (SHELL41 is used to represented CFRP plate, bond between concrete and CFRP plate represented by interface element (CONTAC52. The results obtained from analytical study explained that the best location of CFRP is at lower edges of concrete beam.

  11. Writing Strengthens Orthography and Alphabetic-Coding Strengthens Phonology in Learning to Read Chinese

    Science.gov (United States)

    Guan, Connie Qun; Liu, Ying; Chan, Derek Ho Leung; Ye, Feifei; Perfetti, Charles A.

    2011-01-01

    Learning to write words may strengthen orthographic representations and thus support word-specific recognition processes. This hypothesis applies especially to Chinese because its writing system encourages character-specific recognition that depends on accurate representation of orthographic form. We report 2 studies that test this hypothesis in…

  12. Influence of the protonation of pyridine nitrogen on pnicogen bonding: competition and cooperativity.

    Science.gov (United States)

    Wei, Yuanxin; Li, Qingzhong; Li, Wenzuo; Cheng, Jianbo; McDowell, Sean A C

    2016-04-20

    Ab initio MP2/aug-cc-pVTZ calculations were performed to investigate the pnicogen-bonded complexes of PyZX2 (Py = pyridine, Z = P and As, X = H and F) and their protonated analogues. The selected Lewis bases include H2S, PH3, H2O, NH3, and H2CO. The relative stability of pnicogen-bonded complexes is related to the nature of PyZX2 and bases. When the nitrogen atom of the pyridine ring in PyZX2 is protonated, the protonated complexes are more stabilized than their neutral counterparts, with the interaction energies increased by 8.5-34.6 kJ mol(-1) and the binding distances shortened by 0.050-0.574 Å. Protonation strengthens the pnicogen bond, from a weak interaction to one of moderate strength. In the neutral complexes of PyZX2 and H2O, the formation of a NH-O hydrogen bond is favorable compared to the pnicogen bond. Such inclination is more prominent in the complexes of protonated PyZX2 and NH3. In H2OPyZX2H2O, pnicogen bonding is strengthened by hydrogen bonding due to positive synergistic effects; however, in NH3H(+)-PyZX2NH3, pnicogen bonding is weakened by hydrogen bonding due to negative synergistic effects. PMID:27055488

  13. Mechanical behavior and electrical property of CFRC-strengthened RC beams under fatigue and monotonic loading

    International Nuclear Information System (INIS)

    This study introduces a new CFRC-strengthened RC beam model which can both strengthen and monitor the large-scale RC element used in concrete infrastructures. An experiment of testing four-point bending beams is proceeded in order to analyze mechanical behavior and electrical property of the designed beam under monotonic loading as well as the relationship between electrical property and fatigue damage under cyclic flexural loading. The analytical results indicate that this innovative CFRC-strengthened beam has better flexural performance due to the improved cracking resistance capacity of the CFRC layer. Besides, the change in electrical resistance of the beam is detected under monotonic loading. It is found that the thicker the CFRC layer, the larger the electrical resistance increases, and while electrical resistance irreversibly increases as load cycling progresses, the greater the stress amplitude, the greater the fatigue damage, and the larger the residual resistance increases. Based on this discovery, a new technique to monitor the damage of the designed CFRC-strengthened RC beam is produced by means of resistance measurement

  14. Interface formation and strength of Be/DSCu diffusion bonding

    Energy Technology Data Exchange (ETDEWEB)

    Makino, T. [NGK Insulators Ltd., Nagoya (Japan). Mater. Res. Lab.; Iwadachi, T. [NGK Insulators Ltd., Handa-city (Japan). New Metals Div.

    1998-10-01

    Beryllium has been proposed to be used as a plasma facing material of the first wall for ITER, and will be bonded by HIP process to dispersion strengthened copper (DSCu). Be/DSCu diffusion bonding tests in the range of temperature from 600 C to 850 C by hot pressing techniques have been conducted to identify the effect of bonding temperature and time on interface formation and joint strength. The bonded Be/DSCu joints were evaluated by microstructural analysis of the interface and shear strength tests at room temperature. The diffusion layer of directly bonded Be/DSCu joints and the joints with Be-Cu interlayer consisted of Be{sub 2}Cu({delta}) phase on the Be side and Cu + BeCu({gamma}) phase on the DSCu side, Cu + BeCu({gamma}) phase generated remarkably fast at 800-850 C. The thickness of the diffusion layer was linear to a square root of bonding time. Shear strength of the joints bonded at 650-750 C are all around 200 MPa. Shear strength is dominated by the formation of the layer of Be{sub 2}Cu({delta}) phase on the Be side. (orig.) 2 refs.

  15. Corporate Bonds in Denmark

    DEFF Research Database (Denmark)

    Tell, Michael

    2015-01-01

    Corporate financing is the choice between capital generated by the corporation and capital from external investors. However, since the financial crisis shook the markets in 2007–2008, financing opportunities through the classical means of financing have decreased. As a result, corporations have...... to think in alternative ways such as issuing corporate bonds. A market for corporate bonds exists in countries such as Norway, Germany, France, the United Kingdom and the United States, while Denmark is still behind in this trend. Some large Danish corporations have instead used foreign corporate bonds...

  16. Transversely Compressed Bonded Joints

    DEFF Research Database (Denmark)

    Hansen, Christian Skodborg; Schmidt, Jacob Wittrup; Stang, Henrik

    2012-01-01

    The load capacity of bonded joints can be increased if transverse pressure is applied at the interface. The transverse pressure is assumed to introduce a Coulomb-friction contribution to the cohesive law for the interface. Response and load capacity for a bonded single-lap joint was derived using...... non-linear fracture mechanics. The results indicated a good correlation between theory and tests. Furthermore, the model is suggested as theoretical base for determining load capacity of bonded anchorages with transverse pressure, in externally reinforced concrete structures....

  17. The Halogen Bond

    Science.gov (United States)

    2016-01-01

    The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design. PMID:26812185

  18. Study on WC dispersion-strengthened copper

    Institute of Scientific and Technical Information of China (English)

    WANG Mengjun; ZHANG Liyong; LIU Xinyu

    2004-01-01

    Dispersion-strengthened copper (DSC) with WC as dispersoid was prepared by means of mechanical alloying (MA) following the traditional powder metallurgy (P/M) route. Influence of WC content on the properties of material was discussed in detail, and result shows that when the volume fraction of WC is 1.6%, the material achieves the best overall property, and a little more particle addition led to a less superior property owing to occurrence of particle agglomeration The as-sintered composite was designed to undergo a deformation of 75%. It is proved that appropriate deformation is helpful to attain a higher density and consequently better properties. Deformed material was then exposed to elevated temperature to test its effect on material. Annealing for 1 h at 1173K caused material to recover quite completely, but no obvious recrystallization was observed. It's supposed the particles handicaps motion of dislocations and material demonstrates good retention of strength with substantial improvement in elongation.

  19. TEM study for strengthening mechanisms in elgiloy

    International Nuclear Information System (INIS)

    Elgiloy is Co based alloy (40wt%Co, 20wt%Cr, 15wt%Ni, 14wt%Fe and 7wt%Mo). It was strengthened by cold work and is capable of additional hardening by aging. The effects of solution treatment, cold working and age-hardening on the microstructure of elgiloy were investigated using optical microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). As rolled strips were solution treated at 1065 deg. C/1hr. These solution treated strips were then reduced 50% by cold rolling. After cold-deformation both epsilon-hcp phase and fcc deformation twins are also considered to coexist at room temperature. The cold worked strips were then age hardened at (450-600) deg. C. The age hardened strips showed formation of additional epsilon-phase (via alpha/sub fcc/ EPSILON/sub hcp/ transformation). (author)

  20. Strengthening Injury Surveillance System in Iran

    Institute of Scientific and Technical Information of China (English)

    Seyed Abbas Motevalian; Mashyaneh Haddadi; Hesam Akbari; Reza Khorramirouz; Soheil Saadat; Arash Tehrani; Vafa Rahimi-Movaghar

    2011-01-01

    Objective:To strengthen the current Injury Surveillance System (IS System) in order to better monitor injury conditions,improve protection ways and promote safety.Methods:At first we carried out a study to evaluate the frameworks of IS System in the developed countries.Then all the available documents from World Health OrganizationEastern Mediterranean Regional Organization,as well as Minister of Health and Medical Education concerning Iran were reviewed.Later a national stakeholder's consultation was held to collect opinions and views.A national workshop was also intended for provincial representatives from 41 universities to identify the barriers and limitations of the existing program and further to strengthen injury surveillance.Results:The evaluation of the current IS System revealed many problems,mainly presented as lack of accurate pre- and post-hospital death registry,need of precise injury data registry in outpatient medical centers,incomplete injury data registry in hospitals and lack of accuracy in definition of variables in injury registry.The five main characteristics of current IS System including flexibility,acceptability,simplicity,usefulness and timeliness were evaluated as moderate by experts.Contusions:Major revisions must be considered in the current IS System in Iran.The following elements should be added to the questionnaire:identifier,manner of arrival to the hospital,situation of the injured patient,consumption of alcohol and opioids,other involved participants in the accident,intention,severity and site of injury,side effects of surgery and medication,as well as one month follow-up results.Data should be collected from 10% of all hospitals in Iran and analyzed every 3 months.Simultaneously data should be online to be retrieved by researches.

  1. Strengthening Injury Surveillance System in Iran

    Directory of Open Access Journals (Sweden)

    Motevalian Seyed Abbas

    2012-02-01

    Full Text Available 【Abstract】Objective: To strengthen the current Injury Surveillance System (IS System in order to better monitor injury conditions, improve protection ways and promote safety. Methods: At first we carried out a study to evaluate the frameworks of IS System in the developed countries. Then all the available documents from World Health Organization, Eastern Mediterranean Regional Organization, as well as Minister of Health and Medical Education concerning Iran were reviewed. Later a national stakeholder抯 consultation was held to collect opinions and views. A national workshop was also intended for provincial representatives from 41 universities to identify the barriers and limitations of the existing program and further to strengthen injury surveillance. Results: The evaluation of the current IS System revealed many problems, mainly presented as lack of accurate pre- and post-hospital death registry, need of precise injury data registry in outpatient medical centers, incomplete injury data registry in hospitals and lack of accuracy in definition of variables in injury registry. The five main characteristics of current IS System including flexibility, acceptability, simplicity, usefulness and timeliness were evaluated as moderate by experts. Conclusions: Major revisions must be considered in the current IS System in Iran. The following elements should be added to the questionnaire: identifier, manner of arrival to the hospital, situation of the injured patient, consumption of alcohol and opioids, other involved participants in the accident, intention, severity and site of injury, side effects of surgery and medication, as well as one month follow-up results. Data should be collected from 10% of all hospitals in Iran and analyzed every 3 months. Simultaneously data should be online to be retrieved by researches. Key words: Wounds and injuries; Population surveillance; Registries; Iran

  2. Strengthening of HSLA steels by cool deformation

    International Nuclear Information System (INIS)

    In microalloyed steels, the refinement of ferrite grains together with a controlled amount of precipitation has key roles in the mechanical properties improvement. Applying small amounts of deformation, at very low hot working temperatures (i.e. coiling temperature), in the ferrite region (i.e. cool deformation) has an appreciable strengthening effect via controlling the final microstructure of the steel. One of the microstructural effects is thought to be the much finer and more uniformly dispersed precipitates in the steel matrix. In the present study, the effects of Nb and Cu on mechanical properties and corresponding microstructures in steels with different levels of cool deformation are investigated. The mechanical properties of the samples were determined using the shear punch test and the microstructure was examined by scanning and transmission electron microscopy. Thermodynamic simulations with FactSage were done to further analyze the precipitation possibility of different elements. It has been found that these alloying elements respond very well to cool deformation, with the strength being highest in steels containing both Nb and Cu. However, a cool deformation effect in the non-Nb and Cu bearing steel is also observed. In all cases, it was confirmed that precipitation plays a key role in the effect of cool deformation, with much of the precipitation taking place dynamically. Nevertheless, static processes also seem to have a measurable effect on room temperature properties. Even low amounts of copper (e.g. ∼0.4 wt%) can contribute to strengthening of the steel. The Cu addition is found to affect the mechanical properties by affecting the precipitation and growth of Nb compounds.

  3. Strengthening of HSLA steels by cool deformation

    Energy Technology Data Exchange (ETDEWEB)

    Fatehi, A., E-mail: arya.fatehi@gmail.com [Department of Mining, Metals and Materials Engineering, McGill University, 3610 University Street, Montreal, QC, H3A 2B2 (Canada); Calvo, J.; Elwazri, A.M.; Yue, S. [Department of Mining, Metals and Materials Engineering, McGill University, 3610 University Street, Montreal, QC, H3A 2B2 (Canada)

    2010-06-25

    In microalloyed steels, the refinement of ferrite grains together with a controlled amount of precipitation has key roles in the mechanical properties improvement. Applying small amounts of deformation, at very low hot working temperatures (i.e. coiling temperature), in the ferrite region (i.e. cool deformation) has an appreciable strengthening effect via controlling the final microstructure of the steel. One of the microstructural effects is thought to be the much finer and more uniformly dispersed precipitates in the steel matrix. In the present study, the effects of Nb and Cu on mechanical properties and corresponding microstructures in steels with different levels of cool deformation are investigated. The mechanical properties of the samples were determined using the shear punch test and the microstructure was examined by scanning and transmission electron microscopy. Thermodynamic simulations with FactSage were done to further analyze the precipitation possibility of different elements. It has been found that these alloying elements respond very well to cool deformation, with the strength being highest in steels containing both Nb and Cu. However, a cool deformation effect in the non-Nb and Cu bearing steel is also observed. In all cases, it was confirmed that precipitation plays a key role in the effect of cool deformation, with much of the precipitation taking place dynamically. Nevertheless, static processes also seem to have a measurable effect on room temperature properties. Even low amounts of copper (e.g. {approx}0.4 wt%) can contribute to strengthening of the steel. The Cu addition is found to affect the mechanical properties by affecting the precipitation and growth of Nb compounds.

  4. Experimental and Numerical Research on Seismic Performance of Earthquake-Damaged RC Frame Strengthened with CFRP Sheets

    Directory of Open Access Journals (Sweden)

    Lai Wang

    2016-01-01

    Full Text Available In order to assess the seismic performance of damaged reinforced concrete (RC frame strengthened with carbon fiber reinforced polymers (CFRP sheets, two experimental specimens with identical reinforcement ratio and geometric dimensions were designed following Chinese code for seismic design of buildings. Experimental specimens consist of a reference (undamaged RC frame, namely, KJ-1, and an earthquake-damaged RC frame strengthened with CFRP sheets, namely, KJ-2. A pseudostatic test was conducted on the two specimens to simulate moderate earthquake damage. The strengthening effects of CFRP sheets on damaged RC frame were discussed in terms of hysteretic curve, skeleton curve, stiffness degradation, and ductility. In addition, numerical method based on fiber model method was utilized to analyze the seismic performance of KJ-1 and KJ-2 and it is compared with the experimental result. Both the results confirm that the method of exterior bonding CFRP sheets on the damaged RC frame has restored the seismic performance such as bearing capacity, stiffness, and ductility to its original undamaged level, and some of the seismic performance of the damaged RC frame strengthened with CFRP sheets is even better than the undamaged one, which proves that the method has significant effect in strengthening postearthquake-damaged RC frames.

  5. Strengthening of RC Beams with Large Openings in Shear by CFRP Laminates: Experiment and 2D Nonlinear Finite Element Analysis

    Directory of Open Access Journals (Sweden)

    S.C. Chin

    2012-05-01

    Full Text Available This study presents the experimental study and numerical analysis of Reinforced Concrete (RC beams with large square openings placed in the shear region, at a distance 0.5d and d away from the support, strengthened by Carbon Fiber Reinforced Polymer (CFRP laminates. This research aims to investigate the strength losses in RC beam due to the presence of large square openings placed at two different locations in shear region. Also, in order to re-gain the beam structural capacity loss due to the openings, strengthening by CFRP laminates around the openings were studied. A total of six RC beams were tested to failure under four point loading including control beams, un-strengthened and strengthened RC beams with large square openings in shear region at a distance 0.5d and d away from the support. The CFRP strengthening configuration considered in this study was a full wrapping system around the square openings. A nonlinear finite element program, ATENA was used to validate the results of the tested beams. Comparisons between the finite element predictions and experimental results in terms of crack patterns and load deflection relationships are presented. The crack pattern results of the finite element model show good agreement with the experimental data. The load midspan deflection curves of the finite element models exhibited a stiffer result compared to the experimental beams. The possible reason may be due to the perfect bond assumption between the concrete and steel reinforcement.

  6. Music and social bonding: ‘self-other’ merging and neurohormonal mechanisms

    OpenAIRE

    Bronwyn eTarr; Jacques eLaunay; Robin eDunbar

    2014-01-01

    It has been suggested that a key function of music during its development and spread amongst human populations was its capacity to create and strengthen social bonds amongst interacting group members. However, the mechanisms by which this occurs have not been fully discussed. In this paper we review evidence supporting two thus far independently investigated mechanisms for this social bonding effect: self-other merging as a consequence of inter-personal synchrony, and the release of endorphin...

  7. Stretching and breaking of chemical bonds, correlation of electrons, and radical properties of covalent species

    OpenAIRE

    Sheka, Elena

    2014-01-01

    Chemical bonds are considered in light of correlation of valence electrons that is strengthened when the bond is dissociated. In the framework of the unrestricted Hartree-Fock single-reference version of the configuration interaction theory, effectively unpaired electrons lay the foundation of the electron correlation measure in terms of total number of the electrons (molecular chemical susceptibility). graphs and their singularities with respect to the interatomic distance allow presenting a...

  8. Music and social bonding: “self-other” merging and neurohormonal mechanisms

    OpenAIRE

    Tarr, Bronwyn; Launay, Jacques; Dunbar, Robin I.M.

    2014-01-01

    It has been suggested that a key function of music during its development and spread amongst human populations was its capacity to create and strengthen social bonds amongst interacting group members. However, the mechanisms by which this occurs have not been fully discussed. In this paper we review evidence supporting two thus far independently investigated mechanisms for this social bonding effect: self-other merging as a consequence of inter-personal synchrony, and the release of endorphin...

  9. Static and dynamic experimental study of strengthened reinforced short concrete corbel by using carbon fabrics, crack path in shear zone

    Directory of Open Access Journals (Sweden)

    I. Ivanova

    2015-10-01

    Full Text Available The paper presents an experimental analysis of tracking the path of the cracks and crack growth in strengthened or repair reinforced concrete short corbels bonded by carbon fiber fabrics under static and dynamic loads. The reinforced short concrete corbel is a used precast element, for industrial buildings and structures. In fact, their functioning interestingly unconventional is compared to classical beam type elements. Then the effects of bending and shearing are combined in this case. The horizontal reinforced steel is localized to resist to tensile strength induced in bending top and a transversal strength-absorbing contribution. The introduction of carbon fiber composite in the field of Civil Engineering allows to strengthen or repair reinforced concrete structures using adhesive. So the carbon fiber material has many advantages as its low weight, flexibility, easier handling and also interesting physicochemical properties. However maintenance of civil engineering works is to protect them by ensuring better sealing or limiting corrosion. Then strengthening is to repair structures by using bonding technique to compensate their rigidity loss and limit the cracking. This allows to improve their performance and durability. Bonding of composite material in tensile zone of corbel retrieves most tensile stress and allows the structure to extend their load-bearing capacity. The local behavior of the structure is measured by means of the extensometer technique based on electrical strain gauges. This technique allowed to measure strains of steel, carbon fiber fabrics and concrete. The results of this investigation showed that strengthened reinforced concrete corbel bonded by carbon fiber fabrics can improve the ultimate load to twice and stiffens less than a third. The ultimate load, strain and displacement of the specimen are compared to reference experimental model of monotonic and cyclic applied loads. The success of strengthening depends strongly

  10. Bond dissociation & electronegativity equalization

    OpenAIRE

    Verstraelen, Toon; Ayers, Paul W.; Van Speybroeck, Veronique; Waroquier, Michel

    2012-01-01

    It is well known that the Electrongativity Equalization Mtehod (EEM) fails to describe the charge distribution upon bond dissocation. In this presentation, the bond dissocation is studied with the Atom-Condensed Kohn-Sham DFT approximated to second order (ACKS2). After reviewing the basic equations, a two-fragment system is studied in the dissociation limit. The limiting behavior of the Coulomb interaction (1/r) and the Kohn-Sham matrix elements (exponentially decaying) are plugged into the e...

  11. Anodic bonded graphene

    OpenAIRE

    Balan, Adrian; Kumar, Rakesh; Boukhicha, Mohamed; Beyssac, Olivier; Bouillard, Jean-Claude; Taverna, Dario; Sacks, William; Marangolo, Massimiliano; Lacaze, Emmanuelle; Escoffier, Walter; Poumirol, Jean-Marie; Shukla, Abhay

    2010-01-01

    Abstract We show how to prepare graphene samples on a glass substrate with the anodic bonding method. In this method, a graphite precursor in flake form is bonded to a glass substrate with the help of an electrostatic field and then cleaved off to leave few layer graphene on the substrate. Now that several methods are available for producing graphene, the relevance of our method is in its simplicity and practicality for producing graphene samples of about 100 ?m lateral dimensions. This me...

  12. Handbook of wafer bonding

    CERN Document Server

    Ramm, Peter; Taklo, Maaike M V

    2011-01-01

    Written by an author and editor team from microsystems companies and industry-near research organizations, this handbook and reference presents dependable, first-hand information on bonding technologies.In the first part, researchers from companies and institutions around the world discuss the most reliable and reproducible technologies for the production of bonded wafers. The second part is devoted to current and emerging applications, including microresonators, biosensors and precise measuring devices.

  13. Experimental Study of the Flexural Behaviour of Damaged RC Beams Strengthened in Bending Moment Region with Basalt Fiber Reinforced Polymer (BFRP Sheets

    Directory of Open Access Journals (Sweden)

    Akshay P. Gholkar

    2014-07-01

    Full Text Available This paper presents the flexural behaviour of basalt fiber reinforced polymer (BFRP strengthened reinforced concrete (RC beams. For flexural strengthening of reinforced concrete beams, total twenty-two beams were cast and tested over an effective span of 900 mm up to failure of the beam under two-point loading. The beams were designed as under-reinforced beams. The beams were bonded with BFRP sheets in single layer and double layers in the bending moment region at the bottom face of the beam. Out of the twenty-two beams two beams were control beams and remaining beams were strengthened after being damaged for various degrees of damage (0 %, 70 %, 80 %, 90% and 100 %. The experimental results show that the beams strengthened show high load carrying capacity.

  14. Experimental and Finite Element Studies on CFF Strengthened RC Rectangular Beams in Shear

    Directory of Open Access Journals (Sweden)

    J. Jayaprakash

    2015-08-01

    Full Text Available This paper presents the experimental and finite element (FE results of Reinforced Concrete (RC rectangular beams in shear bonded externally using Carbon Fibre Fabric (CFF reinforcement.  In the experimental study, all, except control, beams were strengthened/repaired with CFF reinforcement at laboratory environment.  These beams were tested under four point bending system for failure.  Moreover, to validate the obtained experimental results, the study used two-dimensional model to simulate the shear behaviour of the CFF repaired/strengthened beams using LUSAS finite element analysis software.  The experimental results confirm that the CFF repaired and initially strengthened beams attained a gain of 37.28% - 77.95% and 60.71% - 77.34% for shear span to effective depth ratio of 2.5 and 4.0, respectively.  The results of FE prediction were compared against the experimental results obtained from the experimental investigation.  It was generally found that the comparison between the predicted FE and experimental results show satisfactory correlation in terms of load-displacement profile.

  15. Behavior of Reinforced Concrete Box Beam Strengthened with CFRP U-Wrap Strips Under Torsion

    Directory of Open Access Journals (Sweden)

    Ma Shengqiang

    2016-01-01

    Full Text Available The present study focuses on the torsional strengthening behavior of reinforced concrete (RC box section beams that are widely used in bridges. Four RC box beams were fabricated, and three of them were wrapped by carbon fiber-reinforced polymer (CFRP U-wrap strips with or without longitudinal strips. The different wrapping configuration, cracking angle, failure pattern, and tensile strain of fibers were investigated and discussed accordingly. The experimental results addressed that U-wrap strips strengthening also can upgrade the ultimate torque of beams moderately. In particular, using U-wrap and longitudinal strips to bond the box beams increased the torsional stiffness slightly. The same equation from different codes for calculating RC specimens can accurately predict the ultimate strength of the control beam, but the calculation of the fib model overestimated the torsional strengthening improvement of the wrapped specimens. However, Ghobarah et al. assumed approximately 3000με of the average ultimate fiber strain in calculating the ultimate strength of the wrapped box beams which shows in relatively appropriate agreement with testing results.

  16. Parameters That Effect the Interfacial Stresses in Fibre Reinforced Plastic Laminates Strengthened Rc Beams

    Directory of Open Access Journals (Sweden)

    Barış Sayın

    2010-01-01

    Full Text Available The use of externally bonded fiber-reinforced plastic (FRP laminates for strengthening of reinforced concrete beams has become an effective method. This method has been used because of the advantages of FRP materials such as their high strength-to-weight ratio, good corrosion resistance, and versatility in coping with different sectional shapes and corners. Many studies on this theme have been carried out since the early 1900s. In this study, interfacial stresses of reinforced concrete beams strengthened with FRP effect the parameters will be studied as experimental and numerical. Adhesives used in the beams applied to FRP's thickness, adhesive type and the state of the concrete surface, produced experimental samples are exposed to the bending effect will be studied as a comparative. Afterwards, by using the ANSYS® WB finite element program to model and analyze RC beams by externally bonding FRP will be carried out. Adhesive thickness, adhesive type, the concrete surface will be performed by entering the parameters for analysis of stress can be obtained as a result. Thus, the analytical expressions of stress and normal stress equations will establish should be modified. Finite element analysis and experimental results will be compared, compatibility investigated, the results and recommendations presented by the study be completed.

  17. Luster Polish Strengthening Treatment for Raceway Surface of Aeroengine Bearings

    Institute of Scientific and Technical Information of China (English)

    DENG Si-er; TENG Hong-fei; MA Fu-jian; HAO Jian-jun; CHEN Tao

    2007-01-01

    A new surface strengthening technology, luster polish strengthening treatnent, was proposed to treat the raceway surface of aeroengine bearings (9Cr18Mo) with the centrifugal strengthening machine exclusively designed for luster polish strengthening treatment. The experimental results showed that luster polish strengthening treatment produced a compressive residual stress layer with a depth of over 80 μm below the surface of the bearing raceway, and thus effectively removed the metamorphic layer in the raceway surface. After luster polish strengthening treatment, the average surface hardness of the aeroengine bearing raceway was increased from 61.02 HRC to 63.01 HRC, the surface roughness was reduced from 0.06 μm to 0.03 μm, and the contact fatigue life of the aeroengine bearings was improved by about 90%, with the dispersion of fatigue life being reduced remarkably.Theoretical calculation result agrees with that obtained by experiment.

  18. Behavior of preloaded RC beams strengthened with CFRP laminates

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Eighteen reinforced concrete beams, including 16 beams strengthened with CFRP laminate at different levels of preload and 2 control beams, were tested to investigate the influence ofpreload level on flexural behavior of CFRP-strengthened RC beam. The experimental parameters include rebar ratios, number of plies of CFRP laminates and preload level at the time of strengthening. Theoretical analysis was also carried out to explain the experimental phenomena and results. The experimental and theoretical results indicated that the preload level has more influence on the stiffness and deflection of the strengthened beam, bothat post-cracking and post-yielding stage, than that on the yielding and ultimate flexural strength of the strengthened beam. The main failure mode of CFRP-strengthened beam is the intermediate crack-induced debonding of CFRP laminates, provided that the development length of CFRP laminates and shear capacity of the beam are sufficient.

  19. Design and behavior of reinforced concrete beams strengthened with fiber-reinforced plastics (FRP)

    Science.gov (United States)

    El-Mihilmy, Mahmoud Tharwat

    A comprehensive investigation of the design and behavior of reinforced concrete beams strengthened with externally bonded FRP laminates has been conducted. The study has confirmed the applicability of the strain compatibility method for calculating the increased ultimate moment capacity of the repaired beams. An upper limit to the amount of FRP that can be added to a specific structure was recommended to ensure ductile behavior. Design charts to facilitate calculations of the ultimate moment capacity for reinforced concrete beams strengthened with FRP laminates were developed. The results of a subsequent parametric investigation indicate that strengthening reinforced concrete beams with FRP laminates can enhance their ultimate capacity by as much as three times the original strength, especially for beams with a low steel ratio. It was also determined that, increasing the concrete compressive strength and the FRP modulus of elasticity increases the beam ultimate flexural capacity significantly; however, the repaired beams are less ductile than the pre-repaired concrete beams. During the course of the study, it had been noticed that the current ACI recommended method for calculating deflections for ordinary reinforced concrete beams does not render an accurate estimate for reinforced concrete beams strengthened with FRP laminates. A simplified equation for predicting the deflection of reinforced concrete beams repaired with FRP was developed and verified with comparisons to experimental results. The effectiveness of strengthening an existing bridge with externally bonded FRP laminates was investigated through comprehensive static and dynamic finite element analyses. The results of these analyses correlate well with field load test results. The repaired girders exhibited an average reduction in reinforcing steel stresses of 11 percent and an average reduction in midspan girder deflections of 9 percent. The results of the study also indicated that existing methods for

  20. Crack-induced debonding failure in fiber reinforced plastics (FRP) strengthened concrete beams: Experimental and theoretical analysis

    Science.gov (United States)

    Pan, Jinlong

    External bonding of FRP plates to the tension substrate of RC beams has been accepted as an efficient and effective technique for flexural strengthening. In this thesis, different problems related to crack-induced debonding of the FRP plate in the flexural strengthened concrete beams have been investigated. FRP strengthened RC beam may fail by FRP debonding from the bottom of a major flexural crack in the span. This kind of failure is studied with the direct shear test in the present research work. Our experimental investigation focuses on the effect of concrete composition on the bond behavior between FRP and concrete. Based on the test results, the bond capacity of the specimen is found to be governed by the concrete surface tensile strength, aggregate size and aggregate content. Then, the neural network is employed to derive an empirical expression for the interfacial fracture energy in terms of concrete surface tensile strength and aggregate content. Using the empirical equation, simulated bond capacity is in good agreement with experimental results. In the FRP strengthened RC beams, debonding of the FRP plate often occurs under the presence of multiple cracks along the span. In the present thesis, experimental and theoretical investigations are performed to study the effect of multiple secondary cracks on the debonding behavior and ultimate load capacity. A new analytical model for FRP debonding under multiple cracks has been developed. The effect of the multiple secondary cracks on the shear softening in the debonded zone is explicitly considered in the model. Using the new model, the simulated values of ultimate load when debonding occurs are in good agreement with measured values. In the FRP strengthened RC beams, concrete cover separation or plate end debonding can be avoided by applying tapers at the FRP plate end. In this situation, it is easier for FRP debonding to be induced by a major flexural crack close to the support. To study the effect of the

  1. APPLICATION OF PRESTRESSED SHELLS TO STRENGTHEN STRIP FOUNDATIONS

    OpenAIRE

    Ter-Martirosjan Zaven Grigor'evich; Pronozin Jakov Aleksandrovich; Naumkina Julija Vladimirovna

    2012-01-01

    Effective method of strengthening of foundations of existing buildings by pre-stressed shells is considered in the paper. Advantages of the proposed strengthening method, its production technology and pre-conditions of its analysis are also presented. Presently, strengthening of ground foundations and foundations of buildings and structures is a relevant civil engineering challenge. It is driven by high intensity of restructuring and modernization of buildings and alteration of geological eng...

  2. How to Strengthen Child Learners’Self-confidence

    Institute of Scientific and Technical Information of China (English)

    李文敬

    2013-01-01

    Self-confidence is closely related to L2 learning. In order to make their learners enjoy English learning, English teach-ers need to strengthen the learners’English learning confidence. This article is to find out English teachers’role to strengthening learners’self-confidence in ELL by means of class observation. The writer concludes improving speaking ability; giving praise and offering gentle error correcting can help to strengthen the learners’confidence.

  3. Use of Woven Fabrics for Strengthening of Reinforced Concrete Beams

    OpenAIRE

    Parthraj R. Puranik; Deval A. Vasavada

    2014-01-01

    Worldwide, a great deal of research is currently being conducted concerning the use of fiber reinforced plastic wraps, laminates and sheets in the repair and strengthening of reinforced concrete (RC) members. Fibre-reinforced polymer (FRP) application is a very effective way to repair and strengthen structures that have become structurally weak over their life span. But the use of woven fabrics for strengthening RC members has not been much investigated. Woven fabrics though cannot provide co...

  4. Bond Length and Bond Order in One of the Shortest Cr-Cr Bonds

    OpenAIRE

    La Macchia, Giovanni; Aquilante, Francesco; Veryazov, Valera; Roos, Bjorn O.; Gagliardi, Laura

    2008-01-01

    Multiconfigurational quantum chemical calculations on the R-diimines dichromium compound confirm that the Cr-Cr bond, 1.80 A, is among the shortest Cr (I)-Cr (I) bonds. However, the bond between the two Cr atoms is only a quadruple bond rather than a quintuple bond. The reason why the bond is so short has to be attributed to the strain in the NCCN ligand moieties.

  5. China and ROK to Strengthen Cooperation in Environmental Issues

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The environment ministers of China and the Republic of Korea have agreed to strengthen bilateral cooperation in tackling regional environmental problems while promoting the development ofrelevant industries.

  6. China Strengthens Macro-management in Petrochemical Branches

    Institute of Scientific and Technical Information of China (English)

    Xu Hui

    1997-01-01

    @@ China will strengthen macro-management in petrochemical branches in order to reasonably utilize the national petroleum resources and improve its competitive capacity in international refinery industrial market.

  7. Monolithic Approach to Oxide Dispersion Strengthened Aluminum Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nassau Stern Company is investigating an approach for manufacturing oxide dispersion strengthened (ODS) aluminum in bulk rather than powder form. The approach...

  8. Fatigue test of RC beams strengthened with prestressed CFLs

    Science.gov (United States)

    Guo, Xinyan; Huang, Peiyan; Liu, Guangwan; Xie, Jianhe

    2008-11-01

    Applying prestress to fiber reinforced polymer (FRP) can be used more efficiently since a greater portion energy of its tensile capacity is engaged. Based on carbon fiber laminate (CFL), fatigue tests are made to find out the fatigue behavior of reinforced concrete (RC) beams strengthened with prestressed CFL. The interfacial debonding is a main failure mode for RC beams strengthened with prestressed CFLs under the cyclic loading. Furthermore, it has been found that the stress value of CFLs decide whether the additional prestressing has a negative or positive effect on the fatigue behavior of the strengthened beam, and the excessive prestressing would reduce the fatigue life of the strengthened beam.

  9. Strengthening Program Pathways through Transformative Change

    Science.gov (United States)

    Rodicio, Lenore; Mayer, Susan; Jenkins, Davis

    2014-01-01

    This chapter reports on a major college-wide effort to smooth students' paths as they enter the college, choose a program, and progress to a credential. Leadership, inclusiveness, and communication have been central to the success of the effort.

  10. Strengthening Science Education in Sri Lanka

    OpenAIRE

    World Bank

    2011-01-01

    Scientific literacy is essential to stimulate an environment conducive to new knowledge generation, discovery and innovation. A quality school science education is central to building a scientifically literate population. Science education in Sri Lanka has progressed both quantitatively and qualitatively since the 1950s. Access to science education has grown steadily. This paper addresses ...

  11. Strengthening brick masonry columns using ferrocement

    International Nuclear Information System (INIS)

    Prior to concrete becoming a widely used building material, brick masonry walls and columns were mainly provided in buildings in most parts of the Indo-Pak Sub-Continent. Quite a large number of these old brick masonry buildings have lost strength, which needs to be restored. A research work was carried out to enhance the strength of brick masonry columns through confinement with ferrocement so as to act as a retrofit arrangement in restoring strength of old brick masonry columns. Composite behavior of masonry columns coated with/without ferrocement having 1, 2 and 3 layers of wire meshes were prepared and tested. Bonding agent was also used for some cases. Test results revealed that the application of ferrocement coating on bare masonry columns enhances the compressive strength quite significantly. Ferrocement specimens having 1 layer of wire mesh wrapped inside showed an increase in failure load up to 134% as compared to control specimen. The cracking resistance and stable crack growth mechanism is also improved. The use of bonding agent does not help in improving load carrying capacity however it is effective in controlling the spalling of concrete cover. (author)

  12. Corrosion analysis of accumulative roll bonded aluminum 6016

    Science.gov (United States)

    Searcy, Jacquelyn Alisha

    Accumulative Roll Bonding is a Severe Plastic Deformation Process that is used to strengthen a material and promote grain refinement. Accumulative Roll Bonded Aluminum 6016 samples were investigated to determine their corrosion properties. The tests performed consisted of standard techniques including Cyclic Polarization Potentials, Exfoliation Corrosion (EXCO), Electrochemical Impedance Spectroscopy (EIS), Light Microscopy, and Electron Microprobe Analysis. From these tests, it was determined that for Al 6016, the Ultra Fine Grained samples obtained by Accumulative Roll Bonding are in general more susceptible to corrosion than the coarse grained sample. The higher corrosion rate was caused by the additional cold work, which increased the number of grain boundaries and rolled-in debris. The advantage however was that the corrosion was parallel to the surface and rather than deep into the sample as with the as-received 6016.

  13. Romanian government bond market

    Directory of Open Access Journals (Sweden)

    Cornelia POP

    2012-12-01

    Full Text Available The present paper aims to present the level of development reached by Romanian government bond market segment, as part of the country financial market. The analysis will be descriptive (the data series available for Romania are short, based on the secondary data offered by the official bodies involved in the process of issuing and trading the Romanian government bonds (Romanian Ministry of Public Finance, Romanian National Bank and Bucharest Stock Exchange, and also on secondary data provided by the Federation of European Stock Exchanges.To enhance the market credibility as a benchmark, a various combination of measures is necessary; among these measures are mentioned: the extension of the yield curve; the issuance calendars in order to improve transparency; increasing the disclosure of information on public debt issuance and statistics; holding regular meetings with dealers, institutional investors and rating agencies; introducing a system of primary dealers; establishing a repurchase (repo market in the government bond market. These measures will be discussed based on the evolution presented inside the paper.The paper conclude with the fact that, until now, the Romanian government bond market did not provide a benchmark for the domestic financial market and that further efforts are needed in order to increase the government bond market transparency and liquidity.

  14. Ion implantations of oxide dispersion strengthened steels

    Science.gov (United States)

    Sojak, S.; Simeg Veternikova, J.; Slugen, V.; Petriska, M.; Stacho, M.

    2015-12-01

    This paper is focused on a study of radiation damage and thermal stability of high chromium oxide dispersion strengthened steel MA 956 (20% Cr), which belongs to the most perspective structural materials for the newest generation of nuclear reactors - Generation IV. The radiation damage was simulated by the implantation of hydrogen ions up to the depth of about 5 μm, which was performed at a linear accelerator owned by Slovak University of Technology. The ODS steel MA 956 was available for study in as-received state after different thermal treatments as well as in ions implanted state. Energy of the hydrogen ions chosen for the implantation was 800 keV and the implantation fluence of 6.24 × 1017 ions/cm2. The investigated specimens were measured by non-destructive technique Positron Annihilation Lifetime Spectroscopy in order to study the defect behavior after different thermal treatments in the as-received state and after the hydrogen ions implantation. Although, different resistance to defect production was observed in individual specimens of MA 956 during the irradiation, all implanted specimens contain larger defects than the ones in as-received state.

  15. Strengthened enforcement enhances marine sanctuary performance

    Directory of Open Access Journals (Sweden)

    Brendan P. Kelaher

    2015-01-01

    Full Text Available Marine sanctuaries are areas where the extraction of biota is not permitted. Although most marine sanctuaries have a positive influence on biotic communities, not all sanctuaries are meeting their conservation objectives. Amidst possible explanations (e.g., size, age and isolation, insufficient enforcement is often speculated to be a key driver of marine sanctuary underperformance. Despite this, there are few studies directly linking quantitative enforcement data to changes in biotic communities within marine sanctuaries. Here, we used an asymmetrical-BACI experimental design from 2006–2012 to test whether new enforcement initiatives enhanced abundances of target fishes and threatened species in an existing large sub-tropical marine sanctuary relative to areas open to fishing. Implementation of the new enforcement initiatives in 2010 was associated with a 201% increase in annual fine rate and a significant increase in target fish and elasmobranch abundance, as well as sightings of a critically-endangered shark, in the marine sanctuary relative to areas open to fishing. Overall, these results demonstrate that strengthening enforcement can have a rapid positive influence on target fish and perhaps threatened species in a subtropical marine sanctuary. From this, we contend that increased enforcement guided by risk-based compliance planning and operations may be a useful first step for improving underperforming marine sanctuaries.

  16. Strengthening CERN’s international relations

    CERN Multimedia

    2010-01-01

    Council’s decision in June to open membership of CERN to the world in a clear and well-defined way means that it’s time to strengthen our international relations. Non-Member State interest, and participation, in CERN has been rising for many years, and with the LHC running smoothly that trend is continuing.   Furthermore, the long-term future of particle physics may well see Europe contributing to facilities in other regions of the world, with European participation coordinated through CERN. It was with these developments in mind that I established the External Relations Office under Felicitas Pauss at the start of my mandate last year. Council’s decision underlines the need for that office, and clarifies its liaison role of with Member and non-Member States. Clarity of function demands clarity of name, so from now on, the Office will be known as the Office for International Relations. It will continue to be headed by Felicitas Pauss. The Office’s main r...

  17. Strengthening safeguards: A developing country perspective

    International Nuclear Information System (INIS)

    A.S. Minty maintained that for developing countries the only guarantee against the use of nuclear weapons is the abolition of such weapons - nuclear non-proliferation and nuclear disarmament are two sides of the same coin. That some States have failed to recognize and act upon this has undermined the NPT. So has the growing resort to unilateralism and unilaterally imposed prescriptions. The only sustainable way of addressing international security issues is through multilateral means, in accordance with the United Nations Charter. In this regard, the IAEA is the appropriate multilateral mechanism for addressing verification issues and challenges. It should be left to do its work unfettered by pressure, hindrance or interference. All States should support the IAEA in its verification tasks, including further improvements to the effectiveness and efficiency of the strengthened safeguards system. The Board of Governors' Advisory Committee on Safeguards and Verification provides a valuable forum at which these issues can be usefully addressed. However, the Committee should not become a focus for arguments in favour of punitive actions

  18. Micropolar crystal plasticity simulation of particle strengthening

    Science.gov (United States)

    Mayeur, J. R.; McDowell, D. L.

    2015-09-01

    The yield and work hardening behavior of a small-scale initial-boundary value problem involving dislocation plasticity in an idealized particle strengthened system is investigated using micropolar single crystal plasticity and is compared with results for the same problem from dislocation dynamics simulations. A micropolar single crystal is a work-conjugate higher-order continuum that treats the lattice rotations as generalized displacements, and supports couple stresses that are work-conjugate to the lattice torsion-curvature, leading to a non-symmetric Cauchy stress. The resolved skew-symmetric component of the Cauchy stress tensor results in slip system level kinematic hardening during heterogeneous deformation that depends on gradients of lattice torsion-curvature. The scale-dependent mechanical response of the micropolar single crystal is dictated both by energetic (higher-order elastic constants) and dissipative (plastic torsion-curvature) intrinsic material length scales. We show that the micropolar model captures essential details of the average stress-strain behavior predicted by discrete dislocation dynamics and of the cumulative slip and dislocation density fields predicted by statistical dislocation dynamics.

  19. Strengthening Self-efficacy through Supportive Mentoring

    Science.gov (United States)

    Haacker, R.

    2015-12-01

    The geosciences have had a chronic problem of underrepresentation of students from diverse ethnic, cultural, gender and socio-economic backgrounds. As a community we need to strengthen our support of young scientists from all backgrounds to sustain their enthusiasm and ensure their success in our field. Investing in mentoring programs that empower students and young professionals is one of the best ways to do so. The Significant Opportunities in Atmospheric Research and Science (SOARS) program, now entering its 20th year, has successfully developed and tested several mentoring models. The personalized, caring and consistent support is one of the key elements of the program's success; since its inception, 90% of SOARS participants have entered graduate school, research or science related careers after graduation. Many of our alumni who are now faculty apply the same mentoring strategies to build self-esteem and perseverance in their students. This presentation will cover the design and implementation of our four mentoring strategies, and provide insights on potential challenges, training aspects and impact assessment. The mentoring strategies include: 1) Multi-faceted, long-term mentoring of undergraduate and graduate students from diverse backgrounds. 2) Empowering advanced students to serve as peer mentors and role models. 3) Training faculty and professional scientists from all backgrounds to become mentors who are aware of diversity issues. 4) Providing mentor training for partner programs and laboratories. All four strategies have contributed to the creation of a mentoring culture in the geosciences.

  20. Nanoscale Cementite Precipitates and Comprehensive Strengthening Mechanism of Steel

    Science.gov (United States)

    Fu, Jie; Li, Guangqiang; Mao, Xinping; Fang, Keming

    2011-12-01

    This article summarizes the state of the art of the comprehensive strengthening mechanism of steel. By using chemical phase analysis, X-ray small-angle scattering (XSAS), room temperature organic (RTO) solution electrolysis and metal embedded sections micron-nano-meter characterization method, and high-resolution transmission electron microscopy (TEM) observation, the properties of nanoscale cementite precipitates in Ti microalloyed high-strength weathering steels produced by the thin slab continuous casting and rolling process were analyzed. Except nanoscale TiC, cementite precipitates with size less than 36 nm and high volume fraction were also found in Ti microalloyed high-strength weathering steels. The volume fraction of cementite with size less than 36 nm is 4.4 times as much as that of TiC of the same size. Cementite with high volume fraction has a stronger precipitation strengthening effect than that of nanoscale TiC, which cannot be ignored. The precipitation strengthening contributions of nanoscale precipitates of different types and sizes should be calculated, respectively, according to the mechanisms of shearing and dislocation bypass, and then be added with the contributions of solid solution strengthening and grain refinement strengthening. A formula for calculating the yield strength of low-carbon steel was proposed; the calculated yield strength considering the precipitation strengthening contributions of nanoscale precipitates and the comprehensive strengthening mechanism of steels matches the experimental results well. The calculated σ s = 630 to 676 MPa, while the examined σ s = 630 to 680 MPa. The reason that "ultrafine grain strengthening can not be directly added with dislocation strengthening or precipitation strengthening" and the influence of the phase transformation on steel strength were discussed. The applications for comprehensive strengthening theory were summarized, and several scientific questions for further study were pointed out.

  1. Effect of Kr :F excimer irradiation on the bond between sealant and enamel

    Institute of Scientific and Technical Information of China (English)

    LU Weiwei; YU Weiyi; SUN Jiao; XUE Miao

    2001-01-01

    @@ Since the invention of Ruby laser by Maiman in 1960s, many kinds of lasers areused widely in dentistry. It has been proved that laser irradiation can produce acidetching like surface, thus strengthen the bond of material to enamel. But the heatgenerated during irradiation produces damage on dental pulp, which limits the laserapplications on dental hard surfaces.

  2. Mechanical properties of HIP bonded W and Cu-alloys joint for plasma facing components

    International Nuclear Information System (INIS)

    Hot isostatic pressing (HIP) bonding technology of W (tungsten) and Cu-alloys have been developed to fabricate plasma facing components of the fusion reactor. As regards W and oxygen free high conductivity copper (OFHC-Cu), the highest bonding strength was achieved at the HIP condition of 1273 Kx2 hx147 MPa. On the other hand, W and dispersion strengthened copper (DS-Cu) were not bonded directly because of tungsten oxide production at the bonding interface. In this study, HIP bonding tests on W and DS-Cu with OFHC-Cu disk and/or Au-foil were performed. Bonding tests with OFHC-Cu disk were successfully bonded and it is shown that thickness of OFHC-Cu disk over 1.0 mm may be needed and the tensile strength are a little higher than that of HIP treated OFHC-Cu. Bonding tests with Au-foil were also performed and successfully bonded. Au-foil lead to an improvement in bonding strength and a lowering of bonding temperature

  3. Strengthening Global Approaches to Nuclear Security

    OpenAIRE

    Bunn, Matthew G.

    2013-01-01

    Despite substantial progress in improving nuclear security in recent years, there is more to be done. The threats of nuclear theft and terrorism remain very real. This paper recommends learning from the much stronger national and international efforts in nuclear safety, and in particular taking steps to build international understanding of the threat; establish effective performance objectives; assure performance; train and certify needed personnel; build security culture and exch...

  4. Strengthening Science Education in Sri Lanka

    OpenAIRE

    Aturupane, Harsha; Dissanayake, Visaka; Jayewardene, Romaine; Shojo, Mari; Sonnadara, Upul

    2011-01-01

    Scientific literacy is essential to stimulate an environment conducive to new knowledge generation, discovery and innovation. A quality school science education is central to building a scientifically literate population. Science education in Sri Lanka has progressed both quantitatively and qualitatively since the 1950s. Access to science education has grown steadily. This paper addresses the challenges to providing a good science education and considers pathways to the future. Policy initiat...

  5. TEXT tf coil bonding system

    International Nuclear Information System (INIS)

    An extensive bond test program was conducted prior to manufacturing and bonding the toroidal field (TF) coils for the Texas Experimental Tokamak (TEXT). The bonding materials consisted of fiberglass cloth with pre-impregnated, 'B' staged Hexcel F-159 resin. Approximately 100 double lap bond samples were constructed to test quality, strength, and repeatability of the bonds. The variables investigated included surface machining methods, surface preparations, bond sample size (planform area), bonding pressure, bonding temperature, and the number of laminations bonded simultaneously. Double lap shear tests conducted at room temperature resulted in ultimate shear strengths for all variables in the range of 3000 to 7000 psi with an average value of 5650 psi. Fatigue tests were also conducted to demonstrate bond integrity over the anticipated cycle lifetime of the TEXT machine (10/sup 6/ cycles) under simulated worst case conditions. 2 refs

  6. Further Developments in Gold-stud Bump Bonding

    OpenAIRE

    Neher, C.; Lander, R. L.; Moskaleva, A.; Pasner, J.; Tripathi, M.; Woods, M.

    2011-01-01

    As silicon detectors in high energy physics experiments require increasingly complex assembly procedures, the availability of a wide variety of interconnect technologies provides more options for overcoming obstacles in generic R&D. Gold ball bonding has been a staple in the interconnect industry due to its ease of use and reliability. However, due to some limitations in the standard technique, alternate methods of gold-stud bonding are being developed. This paper presents recent progress and...

  7. Evaluation of ultrasonic signals from diffusion and eutectic bond interfaces

    Science.gov (United States)

    Brown, C. M.

    1980-12-01

    A research program is in progress at Rocky Flats to determine correlations between ultrasonic signal content and diffusion or eutectic bond joint condition, and to develop a computer-controlled scanning, data acquisition and analysis system which utilizes these correlations and waveform analysis techniques. The initial efforts to determine effective ultrasonic waveform parameters to characterize the strength of bond interfaces is complete. A development version of a computer-controlled, automated scanning and data acquisition system is in operation.

  8. Evaluation of ultrasonic signals from diffusion and eutectic bond interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Brown, C. M.

    1980-12-10

    A research program is in progress at Rocky Flats to determine correlations between ultrasonic signal content and diffusion or eutectic bond joint condition, and to develop a computer-controlled scanning, data acquisition and analysis system which utilizes these correlations and waveform analysis techniques. The initial efforts to determine effective ultrasonic waveform parameters to characterize the strength of bond interfaces is complete. A development version of a computer-controlled, automated scanning and data acquisition system is in operation.

  9. Credible privatization and market sentiment: Evidence from emerging bond markets

    OpenAIRE

    Narjess Boubakri; Jean-Claude Cosset; Houcem Smaoui

    2009-01-01

    This paper investigates the link between privatization and emerging market sovereign bond spreads. We conjecture that the way privatization is implemented may help to build a favorable market sentiment by gradually building investor confidence, which should then lead to a lower required compensation for policy risk. Controlling for other determinants of sovereign bond spreads, we find that privatization proceeds do not affect spreads, while privatization progress and share issues reduce sprea...

  10. Insulation bonding test system

    Science.gov (United States)

    Beggs, J. M.; Johnston, G. D.; Coleman, A. D.; Portwood, J. N.; Saunders, J. M.; Redmon, J. W.; Porter, A. C. (Inventor)

    1984-01-01

    A method and a system for testing the bonding of foam insulation attached to metal is described. The system involves the use of an impacter which has a calibrated load cell mounted on a plunger and a hammer head mounted on the end of the plunger. When the impacter strikes the insulation at a point to be tested, the load cell measures the force of the impact and the precise time interval during which the hammer head is in contact with the insulation. This information is transmitted as an electrical signal to a load cell amplifier where the signal is conditioned and then transmitted to a fast Fourier transform (FFT) analyzer. The FFT analyzer produces energy spectral density curves which are displayed on a video screen. The termination frequency of the energy spectral density curve may be compared with a predetermined empirical scale to determine whether a igh quality bond, good bond, or debond is present at the point of impact.

  11. The Illiquidity of Corporate Bonds

    OpenAIRE

    Bao, Jack; Pan, Jun; Wang, Jiang

    2011-01-01

    This paper examines the illiquidity of corporate bonds and its asset-pricing implications. Using transactions data from 2003 to 2009, we show that the illiquidity in corporate bonds is substantial, significantly greater than what can be explained by bid–ask spreads. We establish a strong link between bond illiquidity and bond prices. In aggregate, changes in market-level illiquidity explain a substantial part of the time variation in yield spreads of high-rated (AAA through A) bonds, overshad...

  12. Health Systems Analysis for Better Health System Strengthening

    OpenAIRE

    Berman, Peter; Bitran, Ricardo

    2011-01-01

    Health system strengthening and reform are often necessary actions to achieve better outcomes. The World Bank's 2007 strategy for health, nutrition, and population emphasizes the importance of health system strengthening for results. This paper proposes 'health systems analysis' as a distinct methodology that should be developed and practiced in the design of policies and programs for heal...

  13. Supporting Teachers, Strengthening Families: A Model Child Abuse Prevention Approach

    Science.gov (United States)

    Olson, Maril

    2007-01-01

    This article talks about a model child abuse prevention approach called, "Supporting Teachers, Strengthening Families." It is NAEYC's professional development initiative to help early childhood educators play leading roles in preventing child abuse and neglect through family strengthening efforts. It focuses on six strategies that high-quality…

  14. Strengthening and Rehabilitation Conventional Methods for Masonry Structures

    OpenAIRE

    Pleşu, Raluca; Ţăranu, George; Covatariu, Daniel; Grădinariu, Ionuţ-Dan

    2011-01-01

    The study and development of rehabilitation and strengthening methods for masonry structures is a permanent concern of civil engineers, because of the high proportion of existing structural masonry and their vulnerability to exceptional loads, especially from seismic action. This paper presents an overview of existing methodologies for strengthening and rehabilitation of masonry structures using traditional materials.

  15. Anodic bonded graphene

    Energy Technology Data Exchange (ETDEWEB)

    Balan, Adrian; Kumar, Rakesh; Boukhicha, Mohamed; Beyssac, Olivier; Bouillard, Jean-Claude; Taverna, Dario; Sacks, William; Shukla, Abhay [Universite Pierre et Marie Curie-Paris 6, CNRS-UMR7590, Institut de Mineralogie et de Physique des Milieux Condenses, 140 rue de Lourmel, Paris, F-75015 France (France); Marangolo, Massimiliano; Lacaze, Emanuelle; Gohler, Roger [Universite Pierre et Marie Curie-Paris 6, CNRS-UMR7588, Institut des Nanosciences de Paris, 140 rue de Lourmel, Paris, F-75015 France (France); Escoffier, Walter; Poumirol, Jean-Marie, E-mail: abhay.shukla@upmc.f [Laboratoire National des Champs Magnetiques Intenses, INSA UPS CNRS, UPR 3228, Universite de Toulouse, 143 avenue de Rangueil, 31400 Toulouse (France)

    2010-09-22

    We show how to prepare graphene samples on a glass substrate with the anodic bonding method. In this method, a graphite precursor in flake form is bonded to a glass substrate with the help of an electrostatic field and then cleaved off to leave few layer graphene on the substrate. Now that several methods are available for producing graphene, the relevance of our method is in its simplicity and practicality for producing graphene samples of about 100 {mu}m lateral dimensions. This method is also extensible to other layered materials. We discuss some detailed aspects of the fabrication and results from Raman spectroscopy, local probe microscopy and transport measurements on these samples.

  16. The Trouble With Bonds

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ In early June,global financial markets gyrated downwards in the wake of central banks'tough language on inflation.At one point bond prices reflected expectations of four rate hikes by the US Federal Reserve (Fed) in the next 12 months.As a result,the dollar firmed,oil prices stabilized,and yield curves flattened around the world.If all these inflation-fighting measures are real,the situation bodes well for bonds.But,I think otherwise.

  17. On-line tribochemical strengthening of gear surface

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    It has been found that under favorable friction conditions some antiwear elements inlubricating additives can permeate into subsurface of metal which can strengthens the friction sur-faces and improves anti-wear capacity of frication pairs. It is in many ways similar to chemical heattreatment. A new concept, technology of on-line strengthening, was logically put forward. Based oncurrent gear surface treatment technology, the on-line strengthen of gear surface is proposed. Itsdesign method is established. Based on it, the on-line strengthen of gear is achieved on CL-100gear test machine. A new method is put forward for strengthen treatment of gear surface. Andthree kinds of surface film were suggested.

  18. Use of Woven Fabrics for Strengthening of Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Parthraj R. Puranik

    2014-03-01

    Full Text Available Worldwide, a great deal of research is currently being conducted concerning the use of fiber reinforced plastic wraps, laminates and sheets in the repair and strengthening of reinforced concrete (RC members. Fibre-reinforced polymer (FRP application is a very effective way to repair and strengthen structures that have become structurally weak over their life span. But the use of woven fabrics for strengthening RC members has not been much investigated. Woven fabrics though cannot provide compressive strength, but have a great potential to provide bending or tensile strength to RC beams. In the present investigation, three different woven fabrics were used to strengthen RC beams. The aim is to study the effectiveness of woven fabric in strengthening of RC beams and the effect of number of fabric layers on load carrying capacity of RC beams.

  19. Metal-Metal Bonding in Uranium-Group 10 Complexes.

    Science.gov (United States)

    Hlina, Johann A; Pankhurst, James R; Kaltsoyannis, Nikolas; Arnold, Polly L

    2016-03-16

    Heterobimetallic complexes containing short uranium-group 10 metal bonds have been prepared from monometallic IU(IV)(OAr(P)-κ(2)O,P)3 (2) {[Ar(P)O](-) = 2-tert-butyl-4-methyl-6-(diphenylphosphino)phenolate}. The U-M bond in IU(IV)(μ-OAr(P)-1κ(1)O,2κ(1)P)3M(0), M = Ni (3-Ni), Pd (3-Pd), and Pt (3-Pt), has been investigated by experimental and DFT computational methods. Comparisons of 3-Ni with two further U-Ni complexes XU(IV)(μ-OAr(P)-1κ(1)O,2κ(1)P)3Ni(0), X = Me3SiO (4) and F (5), was also possible via iodide substitution. All complexes were characterized by variable-temperature NMR spectroscopy, electrochemistry, and single crystal X-ray diffraction. The U-M bonds are significantly shorter than any other crystallographically characterized d-f-block bimetallic, even though the ligand flexes to allow a variable U-M separation. Excellent agreement is found between the experimental and computed structures for 3-Ni and 3-Pd. Natural population analysis and natural localized molecular orbital (NLMO) compositions indicate that U employs both 5f and 6d orbitals in covalent bonding to a significant extent. Quantum theory of atoms-in-molecules analysis reveals U-M bond critical point properties typical of metallic bonding and a larger delocalization index (bond order) for the less polar U-Ni bond than U-Pd. Electrochemical studies agree with the computational analyses and the X-ray structural data for the U-X adducts 3-Ni, 4, and 5. The data show a trend in uranium-metal bond strength that decreases from 3-Ni down to 3-Pt and suggest that exchanging the iodide for a fluoride strengthens the metal-metal bond. Despite short U-TM (transition metal) distances, four other computational approaches also suggest low U-TM bond orders, reflecting highly transition metal localized valence NLMOs. These are more so for 3-Pd than 3-Ni, consistent with slightly larger U-TM bond orders in the latter. Computational studies of the model systems (PH3)3MU(OH)3I (M = Ni, Pd) reveal

  20. Flax Fiber - Interfacial Bonding

    Science.gov (United States)

    Measured flax fiber physical and chemical properties potentially impact bonding and thus stress transfer between the matrix and fiber within composites. These first attempts at correlating flax fiber quality and biofiber composites contain the initial steps towards identifying key flax fiber charac...

  1. Bonds Between Atoms.

    Science.gov (United States)

    Holden, Alan

    The field of inquiry into how atoms are bonded together to form molecules and solids crosses the borderlines between physics and chemistry encompassing methods characteristic of both sciences. At one extreme, the inquiry is pursued with care and rigor into the simplest cases; at the other extreme, suggestions derived from the more careful inquiry…

  2. Thread bonds in molecules

    CERN Document Server

    Ivlev, B

    2015-01-01

    Unusual chemical bonds are proposed. Each bond is almost covalent but is characterized by the thread of a small radius $\\sim 0.6\\times 10^{-11}$cm, between two nuclei in a molecule. The main electron density is concentrated outside the thread as in a covalent bond. The thread is formed by the electron wave function which has a tendency to be singular on it. The singularity along the thread is cut off by electron "vibrations" due to the interaction with zero point electromagnetic oscillations. The electron energy has its typical value of (1-10)eV. Due to the small tread radius the uncertainty of the electron momentum inside the thread is large resulting in a large electron kinetic energy $\\sim 1 MeV$. This energy is compensated by formation of a potential well due to the reduction of the energy of electromagnetic zero point oscillations. This is similar to formation of a negative van der Waals potential. Thread bonds are stable and cannot be created or destructed in chemical or optical processes.

  3. Numerical Determination of Shear Strength of Steel Reinforced Concrete Column Strengthened by CFRP Sheets

    Institute of Scientific and Technical Information of China (English)

    王铁成; 余流; 王立军

    2003-01-01

    The earthquake-resistant property of reinforced concrete members depends on the interaction between reinforcing bars and surrounding concrete through bond to a large degree. In this paper a general system aimed at dealing with the failure analysis of reinforced concrete columns strengthened with carbon-fiber-reinforced plastic (CFRP) sheets including bond-slip of the anchored reinforcing bars at the foot of the columns is presented. It is based on the yield design theory with a mixed modeling of the structure, according to which the concrete material is treated as a classical two-dimensional continuum, whereas the longitudinal reinforcing bars are regarded as one-dimensional rods including bond-slip at the foot of the columns. In shear reinforced zones both the shear CFRP sheets and transverse reinforcing bars are incorporated in the analysis through a homogenization procedure and they are only in tension. The approach is then implemented numerically by means of the finite-element formulation. The numerical procedure produces accurate estimates for the loading-carrying capacity of the shear members taken as an illustrative application by correlation with the experimental results, so the proposed approach is valid.

  4. The Efficiency of Basalt Fibres in Strengthening the Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Andreea Şerbescu

    2006-01-01

    Full Text Available The technique of externally bonding fibre reinforced polymer (FRP composite laminates on the tension side of reinforced concrete (RC beams is already widely accepted as an easy to apply, corrosion resistant and effective solution due to the high strength as well as the low weight of the composite material. The basalt fibres are produced from volcano rocks by a simple process; their applicability as reinforcing material composites utilized for plate bonding of RC beams was not enough researched up to now but it seems to be a cost-effective, durable and fire resistant alternative to traditional fibres. High basalt fiber’s advantages, related to physical-mechanical characteristics and cost, stipulate a new high efficient structural composite materials, which can replace asbestos, metal, timber, plastic materials, etc. The paper investigates the applicability of externally bonded Basalt Fibre Reinforced Polymer (BFRP laminates in strengthening of rectangular reinforced section of a RC beam. The influence of the cross-sectional BFRP area on service and ultimate bending moments and also on service deflection, are analysed. The procedure is based on section analysis, equilibrium of forces and compatibility of strains, considered appropriate for any type of fibres, in case of rectangular RC beams.

  5. Strengthening state/non-state service delivery partnerships in the health sector in Nepal.

    Science.gov (United States)

    Marasini, Baburam; Chaulagai Oli, Chandrakala; Taylor, Judy

    2015-07-01

    State/non-state partnerships in the health sector are of crucial importance in Nepal where partnerships between the Ministry of Health and Population (MoHP) and external actors have been fundamental to Nepal making progress in meeting millennium development goals. However, partnerships need to be strengthened.To gather information about partnerships we searched MoHP partnership evaluations as well as PubMed Central, EBSCOhost, OVIDSP, PROQUEST, Science Direct, and MedLine. We found 11 MoHP documents and 167 papers about state/non-state partnerships. Using the inclusion criteria we examined three MoHP policy documents/evaluations and 16 papers to extract information about partners, partnership health area focus, partner contributions, partnership outcomes, and partnership functioning themes. Themes about partnership functioning include the need to strengthen clarity of roles and responsibilities, strengthen leadership, as well as to ensure integration of partnership achievements systemically within the health sector.There were limitations in this review. In the academic literature there were no studies where the state/non-state partnership itself was evaluated. The focus was on the health outcomes and the partnership processes and functioning received little attention. To improve partnerships there is a serious need for research that evaluates the effectiveness of the partnership and the relationships between the partnership and the health outcomes achieved. PMID:25878212

  6. Shear Strengthening of Corbels with Carbon Fibre Reinforced Polymers (CFRP

    Directory of Open Access Journals (Sweden)

    Nawaz, A.

    2010-09-01

    Full Text Available Corbels constitute what are known as “disturbed” regions in concrete structures, where typical shear failure may be anticipated on the grounds of small shear span-to-depth ratios. The concentration of stress induced by the weight of girders on the very small loadbearing areas in corbels often causes cracking in bridges and other structures. Little experimental research can be found in the literature on the shear strengthening of corbels. In the present study, nine such members were tested. Two had no carbon fibre reinforced polymers attached, while CFRP laminates were externally bonded to the other seven, in a number of different spatial arrangements. Ultimate shear strength was found and compared for all specimens. The results showed that CFRP configuration and geometry directly affected corbel shear strength, which was higher in all the CFRPstrengthened corbels than in the controls. The highest strength values were recorded for specimens whose shear-critical area was wrapped in CFRP.

    Las ménsulas constituyen lo que conocemos como regiones de “distorsión” en las estructuras de hormigón, zonas en que pueden preverse roturas por cortante debido a las bajas relaciones luz de cortante-canto presentes en ellas. La concentración de solicitaciones producida por el peso de las vigas sobre superficies de carga muy reducidas en las ménsulas a menudo provoca el agrietamiento de puentes y otras estructuras de obra civil. En la literatura especializada sobre el refuerzo a cortante de las ménsulas existen escasos ejemplos de estudios experimentales. Para la presente investigación se han realizado ensayos con nueve elementos de este tipo. Dos de ellos no incluían polímeros reforzados con fibra de carbono (CFRP, mientras que los siete restantes llevaban láminas externas de CFRP, dispuestas siguiendo distintas configuraciones espaciales. Los resultados indican que la configuración y la disposición geométrica de los CFRP repercuten

  7. Strengthening of Porcelain Provided by Resin Cements and Flowable Composites.

    Science.gov (United States)

    Spazzin, A O; Guarda, G B; Oliveira-Ogliari, A; Leal, F B; Correr-Sobrinho, L; Moraes, R R

    2016-01-01

    This study evaluated the effect of mechanical properties of resin-based luting agents on the strength of resin-coated porcelain. The luting agents tested were two flowable resin composites (Filtek Z350 Flow and Tetric-N Flow), a light-cured resin cement (Variolink Veneer [VV]), and a dual-cured resin cement (Variolink II) in either light-cured (base paste) or dual-cured (base + catalyst pastes [VD]) mode. Flexural strength (σf) and modulus of elasticity (Ef) of the luting agents were measured in three-point bending mode (n=5). Porcelain discs (Vita VM7) were tested either untreated (control) or acid etched, silanized, and coated with the luting agents. Biaxial flexural strength (σbf) of the porcelain discs was tested using a ball-on-ring setup (n=30). The σbf of the resin-coated specimens was calculated at z-axial positions for multilayer specimens in the ball-on-ring test: position z = 0 (ceramic surface at the bonded interface) and position z = -t2 (luting agent surface above ring). The σf and Ef data were subjected to analysis of variance and the Student-Newman-Keuls test (α=0.05). A Weibull analysis was performed for σbf data. Weibull modulus (m) and characteristic strength (σ0) were calculated. Linear regression analyses investigated the relationship between mechanical properties of the luting agents and the strengthening of porcelain. VD had higher and VV had lower mechanical strength than the other materials. At z = 0, all resin-coated groups had higher σbf than the control group. No significant differences between the luting agents were observed for σbf and σ0. At z = -t2, VD had the highest σbf and σ0, whereas VV had the poorest results. No significant differences in m were observed across groups. A linear increase in flexural strength of the porcelain was associated with increased σf and Ef of the luting agents at position z = -t2. In conclusion, resin coating and use of luting agents with better physical properties generally improved the

  8. Convertible bond valuation focusing on Chinese convertible bond market

    OpenAIRE

    Yang, Ke

    2010-01-01

    This paper mainly discusses the methods of valuation of convertible bonds in Chinese market. Different from common convertible bonds in European market, considering the complicate features of Chinese convertible bond, this paper represents specific pricing approaches for pricing convertible bonds with different provisions along with the increment of complexity of these provisions. More specifically, this paper represents the decomposing method and binomial tree method for pricing both of Non-...

  9. Safeguards implementation and strengthening in Belarus

    International Nuclear Information System (INIS)

    transportation of nuclear materials is carried out by Promatomnadzor. Promatomnadzor also issues permits on movement of nuclear materials across the borders of Belarus. State Customs Committee is responsible for detection of unauthorised imports and exports of nuclear and other radioactive materials at the customs border of the Republic of Belarus. They report each case to other responsible authorities. Belarus is a transport corridor between the East and West, and the issues relating to regulation of export and import, exercising control over export, import of nuclear materials, prevention of smuggling of nuclear materials and maintaining of international co-operation are very important for us. Further development of the safeguards system - It should be noted that control over use of nuclear materials and facilities, which is still of crucial importance can not ensure the absence of undeclared nuclear activities as required. The IAEA has developed the strengthened safeguards system (INFIRC/590) the essence of which is to expand control over relevant technologies, dual use commodities and services. Of course, the implementation of the system provides for more effective and efficient safeguards. Co-operation with the IAEA and other international organisations is regarded as one of the conditions of further improvement of reliability and efficiency of the safeguards. In conclusion I would like to express my profound gratitude to the IAEA and donor countries, in particular Japan, USA and Sweden, for their assistance aimed at strengthening safeguards in Belarus. (author)

  10. Hydrogen bonding tunes the early stage of hydrogen-atom abstracting reaction.

    Science.gov (United States)

    Yang, Yang; Liu, Lei; Chen, Junsheng; Han, Keli

    2014-09-01

    The spontaneous and collision-assisted hydrogen-atom abstracting reaction (HA) dynamics of triplet benzil are investigated through the combination of transient absorption spectroscopy with TD-DFT calculations. HA dynamics exhibit a remarkable dependence on the hydrogen donor properties. The effects of the triplet-state hydrogen bonding on the reaction dynamics are illustrated. In particular, it is experimentally observed that strengthened triplet-state hydrogen bonding could accelerate the HA, whereas weakened triplet-state hydrogen bonding would postpone the HA. The triplet-state hydrogen bonding has great influences on the early stage of the HA reaction, while the bond dissociation energy of the hydrogen donors determines the subsequent reaction pathways. Protic solvents could sustain longer lifetimes of the excited-state intermediate formed after HA than non-protic solvents by 10 μs. This investigation provides insights into the HA dynamics and guidance to improve the product efficiency of photochemical reactions. PMID:25036436

  11. Interface structure of Be/DSCu diffusion bonding

    Energy Technology Data Exchange (ETDEWEB)

    Makino, T.; Iwadachi, T. [NGK Insulators Ltd., Nagoya (Japan)

    1998-01-01

    Beryllium is used as plasma facing components of the first wall on ITER. Dispersion-Strengthened Copper (DSCu) is used as heat sink material by joining to Be because DSCu has high thermal conductivity and strength. In this study, Be/DSCu diffusion bonding tests using the interlayer of Al, Ni, Nb, Ti, Zr and Be-Cu alloy have been conducted to choose the suitable interlayer materials. As a result of the shear strength tests, Be/DSCu joints by using Be-Cu alloy interlayer showed the strength of about 200 MPa. Diffusion bonding tests using Be-Cu alloy interlayer or no interlayer (direct bonding) at the range of temperature from 600degC to 850degC have been conducted to identify the effect of bonding temperature and time on interface formation and strength. The thickness of diffusion layer was proportional to a square root of bonding time by diffusion controlled process. The shear strength is controlled by the formation of intermetallic layer at Be side. (author)

  12. History of Resistance Welding Oxide Dispersion Strengthened Cladding and other High Temperature Materials at Center for Advanced Energy Studies

    Energy Technology Data Exchange (ETDEWEB)

    Larry Zirker; Nathan Jerred; Dr. Indrajit Charit; James Cole

    2012-03-01

    Research proposal 08-1079, 'A Comparative Study of Welded ODS Cladding Materials for AFCI/GNEP,' was funded in 2008 under an Advanced Fuel Cycle Initiative (AFCI) Research and Development Funding Opportunity, number DE-PS07-08ID14906. Th proposal sought to conduct research on joining oxide dispersion strengthen (ODS) tubing material to a solid end plug. This document summarizes the scientific and technical progress achieved during the project, which ran from 2008 to 2011.

  13. Effect of eccentric isokinetic strengthening in the rehabilitation of patients with knee osteoarthritis: Isogo, a randomized trial

    OpenAIRE

    Jegu, Anne-Gaëlle; Pereira, Bruno; Andant, Nicolas; Coudeyre, Emmanuel

    2014-01-01

    Background Femorotibial knee osteoarthritis is associated with muscle weakness in the lower limbs, particularly in the quadriceps, which results in disease progression. The interest of having muscular strengthening as part of the therapeutic arsenal for the medical treatment of knee osteoarthritis is now well established. The functional disability induced by knee osteoarthritis manifests itself principally when walking, notably downhill, during which the muscles are called upon to contract ec...

  14. The strengthening of the Lavaud-Gelade dam; Le confortement de la digue de Lavaud-Gelade

    Energy Technology Data Exchange (ETDEWEB)

    Devos, J.C. [IDTPE, Direction Regionale de l`Industrie, de la Recherche et de l`Environnement (DRIRE), (France); Legras, F. [ITPE, (France)

    1996-12-31

    The Lavaud-Gelade dam (Creuse, France) was built in 1931 and operated by Electricite de France (EdF) since 1946. It is made of loam (clay and sand) with a stone protective cover. The progressive increase of leaks which started in 1982 has led to a project of strengthening of the dam which is detailed in this paper (conclusion of the safety studies, works and costs). The surveillance system has been modified and improved too. (J.S.)

  15. Modelling of the Through-air Bonding Process

    Directory of Open Access Journals (Sweden)

    M. Hossain

    2009-06-01

    Full Text Available A computational fluid dynamics (CFD modelling ofthe through-air bonding process of nonwoven fabricproduction is reported in this article. In the throughairprocess, hot air is passed through the fibrous webto heat and melt polymer fibers. Molten polymersubsequently flows to the point of contact betweenany two fibers to produce a bond. Two differentmodelling strategies are adapted to produce acomprehensive understanding of the through-airbonding process. In macroscale modelling, a CFDmodel is developed treating the whole web as aporous media in order to investigate the effect ofprocess parameters. Results reveal that the timerequired to heat and melt the fibers decreases with theincreasing porosity of the web and the velocity of hotair. The CFD modelling technique is then used toanalyze the bonding process at a more fundamentallevel by considering the bonding of individual fibersat microscale. The effects of the fiber diameter,bonding temperature and contact angle between twofibers on the bonding time are investigated. Resultsshow that the time required to bond fibers is weaklyrelated to bonding temperature and fiber diameter.Fiber orientation angle, on the other hand, hassignificant effect on the progression of bondformation.

  16. Domestic Bond Market Development

    OpenAIRE

    Jonathan A. Batten; Szilagyi, Peter G.

    2007-01-01

    A two-tiered approach to financial market development aimed at both bank and bond market reform would also be complementary to longer term economic development, provided services could be delivered through efficient financial and legal institutions (Chakraborty and Ray 2006) and there was strong protection for investors and sound fiscal and monetary policy management by government (Burger and Warnock 2006b). Historically, local issuers tend to issue in the major currencies (U.S. dollars, yen,...

  17. Bond strength of composite resin to enamel: assessment of two ethanol wet-bonding techniques.

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2014-04-01

    Full Text Available Ethanol wet-bonding (EWB technique has been stated to decrease degradation of resin-dentin bond. This study evaluated the effect of two EWB techniques on composite resin-to-enamel bond strength.Silicon carbide papers were used to produce flat enamel surfaces on the buccal faces of forty-five molars. OptiBond FL (OFL adhesive was applied on enamel surfaces in three groups of 15 namely: Enamel surface and OFL (control;Protocol 1 of the EWB technique: absolute ethanol was applied to water-saturated acid-etched enamel surfaces for 1 minute before the application of ethanol-solvated hydrophobic adhesive resin of OFL 3 times;Protocol 2: progressive ethanol replacement; water was gradually removed from the enamel matrix using ascending ethanol concentrations before OFL application. Composite build-ups were made and the specimens were stored for 24 hours at 37°C and 100% relative humidity. Shear bond strength test was performed using a universal testing machine at 1 mm/min crosshead speed. Fracture patterns were evaluated microscopically. Data were analyzed with one-way ANOVA and Fisher's exact test (α=0.05.There were no significant differences in bond strength between the groups (P=0.73. However, regarding failure patterns, the highest cohesive enamel fractures were recorded in groups 2 and 3.In this study, although both methods of EWB did not influence immediate bond strength of composite resin to enamel, the majority of failure patterns occurred cohesively in enamel.

  18. Disulfide bonds of acetylcholinesterase

    International Nuclear Information System (INIS)

    The positions of the inter- and intrasubunit disulfide bridges were established for the 11S form of acetylcholinesterase (AChE) isolated from Torpedo californica. A major form of AChE localized within the basal lamina of the synapse is a dimensionally asymmetric molecule which contains either two (13S) or three (17S) sets of catalytic subunits linked to collagenous and non-collagenous structural subunits. Limited proteolysis yields a tetramer of catalytic subunits which sediments at 11S. Each catalytic subunit contains 8 cysteine residues. Initially, these Cys residues were identified following trypsin digestion of the reduced protein alkylated with [14C]-iodoacetate. Peptides were resolved by gel filtration followed by reverse phase HPLC. To determine the disulfide bonding profile, native non-reduced 11S AChE was treated with a fluorescent, sulfhydryl-specific reagent, monobromobimane, prior to proteolytic digestion. One fluorescent Cys peptide was identified indicating that a single sulfhydryl residue was present in its reduced form. Three pairs of disulfide bonded peptides were identified, sequenced, and localized in the polypeptide chain. The Cys residue that is located in the C-terminal tryptic peptide was disulfide bonded to an identical peptide and thus forms the intersubunit crosslink. Finally, the cysteine positions have been compared with the sequence of the homologous protein, thyroglobulin. Both likely share a common pattern of folding

  19. Integration of European Bond Markets

    OpenAIRE

    Christiansen, Charlotte

    2012-01-01

    I investigate the time variation in the integration of EU government bond markets. The integration is measured by the explanatory power of European factor portfolios for the individual bond markets for each year. The integration of the government bond markets is stronger for EMU than non-EMU members and stronger for old than new EU members. The integration is weaker for the sovereign debt crisis countries than for other countries. The integration of the EU bond markets is decreasing over time...

  20. Doseringsutrustningen SafeBond Electronic

    OpenAIRE

    Bodegren, Patrik

    2003-01-01

    This thesis for the Master of Science degree was performed at Oppunda Electronics AB. The assignment was to further develop an existing prototype of a dispensing equipment. The dispensing equipment doses a kind of glue, bonding which dentist use to mend teeth. The dispensing equipment is adjusted to dose 12 micro litres of bonding. With the dispensing equipment SafeBond Electronic the user can reduce the bonding consumption with approximately 50 percent. Furthermore will the handling of the b...

  1. Effect of Thermal Distress on Residual Behavior of CFRP-Strengthened Steel Beams Including Periodic Unbonded Zones

    Directory of Open Access Journals (Sweden)

    Isamu Yoshitake

    2015-11-01

    Full Text Available This paper presents the residual behavior of wide-flange steel beams strengthened with high-modulus carbon fiber-reinforced polymer (CFRP laminates subjected to thermal loading. Because the coefficients of thermal expansion of the steel and the CFRP are different, temperature-induced distress may take place along their interface. Periodic unbonded zones are considered to represent local interfacial damage. Five test categories are designed depending on the size of the unbonded zones from 10 to 50 mm, and corresponding beams are loaded until failure occurs after exposing to a cyclic temperature range of ΔT = 25 °C (−10 to 15 °C up to 84 days. The composite action between the CFRP and the steel substrate is preserved until yielding of the beams happens, regardless of the thermal cycling and periodic unbonded zones. The initiation and progression of CFRP debonding become apparent as the beams are further loaded, particularly at geometric discontinuities in the vicinity of the unbonded zones along the interface. A simple analytical model is employed to predict the interfacial stress of the strengthened beams. A threshold temperature difference of ΔT = 30 °C is estimated for the initiation and progression of CFRP debonding. Multiple debonding-progression stages in conjunction with the extent of thermal distress appear to exist. It is recommended that high-modulus CFRP be restrictively used for strengthening steel members potentially exposed to a wide temperature variation range.

  2. The effects of hip muscle strengthening on knee load, pain, and function in people with knee osteoarthritis: a protocol for a randomised, single-blind controlled trial

    Directory of Open Access Journals (Sweden)

    Hunter David J

    2007-12-01

    Full Text Available Abstract Background Lower limb strengthening exercises are an important component of the treatment for knee osteoarthritis (OA. Strengthening the hip abductor and adductor muscles may influence joint loading and/or OA-related symptoms, but no study has evaluated these hypotheses directly. The aim of this randomised, single-blind controlled trial is to determine whether hip abductor and adductor muscle strengthening can reduce knee load and improve pain and physical function in people with medial compartment knee OA. Methods/Design 88 participants with painful, radiographically confirmed medial compartment knee OA and varus alignment will be recruited from the community and randomly allocated to a hip strengthening or control group using concealed allocation stratified by disease severity. The hip strengthening group will perform 6 exercises to strengthen the hip abductor and adductor muscles at home 5 times per week for 12 weeks. They will consult with a physiotherapist on 7 occasions to be taught the exercises and progress exercise resistance. The control group will be requested to continue with their usual care. Blinded follow up assessment will be conducted at 12 weeks after randomisation. The primary outcome measure is the change in the peak external knee adduction moment measured during walking. Questionnaires will assess changes in pain and physical function as well as overall perceived rating of change. An intention-to-treat analysis will be performed using linear regression modelling and adjusting for baseline outcome values and other demographic characteristics. Discussion Results from this trial will contribute to the evidence regarding the effect of hip strengthening on knee loads and symptoms in people with medial compartment knee OA. If shown to reduce the knee adduction moment, hip strengthening has the potential to slow disease progression. Trial Registration Australia New Zealand Clinical Trials Registry ACTR12607000001493

  3. Engagement in muscular strengthening activities is associated with better sleep

    Directory of Open Access Journals (Sweden)

    Paul D. Loprinzi

    2015-01-01

    Full Text Available Few studies have examined whether engagement in muscular strengthening activities is associated with sleep duration, which was the purpose of this study. Data from the population-based 2005–2006 National Health and Nutrition Examination Survey were used, which included an analytic sample of 4386 adults (20–85 yrs. Sleep duration and engagement in muscle strengthening activities was self-reported. After adjustments (including aerobic-based physical activity, those engaging in muscular strength activities, compared to those not engaging in muscular strengthening activities, had an 19% increased odds of meeting sleep guidelines (7–8 h/night (Odds Ratio = 1.19, 95% Confidence Interval: 1.01–1.38, P = 0.04. Promotion of muscular strengthening activities by clinicians should occur not only for improvements in other aspects of health (e.g., cardiovascular benefits, but also to help facilitate optimal sleep duration.

  4. Shear capacity of reinforced concrete columns strengthened with CFRP sheet

    Institute of Scientific and Technical Information of China (English)

    XIE Jian; LIU Xue-mei; ZHAO Tong

    2005-01-01

    This paper discusses the results of tests on the shear capacity of reinforced concrete columns strengthened with carbon fiber reinforced plastic (CFRP) sheet. The shear transfer mechanism of the specimens reinforced with CFRP sheet was studied. The factors affecting the shear capacity of reinforced concrete columns strengthened with CFRP sheet were analyzed. Several suggestions such as the number of layers, width and tensile strength of the CFRP sheet are proposed for this new strengthening technique. Finally, a simple and practical design method is presented in the paper. The calculated results of the suggested method are shown to be in good agreement with the test results. The suggested design method can be used in evaluating the shear capacity of reinforced concrete columns strengthened with CFRP sheet.

  5. Strengthening IAEA safeguards using high-resolution commercial satellite imagery

    International Nuclear Information System (INIS)

    The proliferation of nuclear weapons poses great threat to international peace and security. How to strengthen the non-proliferation regime has become a central question. In May 1997, the IAEA Board of Governors adopted the Additional Safeguards Protocol to improve its ability to detect the undeclared production of fissile material. This new strengthened safeguards system has opened the door for the IAEA to use of all types of information, including the potential use of commercial satellite imagery. We have therefore been investigating the feasibility of strengthening IAEA safeguards using commercial satellite imagery. This paper explores the new roles of high-resolution commercial satellite imagery to monitor the nuclear proliferation. Based on our analysis on a number of one-meter resolution IKONOS commercial satellite images of nuclear facilities, we found that the new high-resolution commercial satellite imagery would play a new and valuable role in strengthening IAEA safeguards. (author)

  6. Predicting sales performance: Strengthening the personality – job performance linkage

    NARCIS (Netherlands)

    T.B. Sitser (Thomas)

    2014-01-01

    markdownabstract__Abstract__ Many organizations worldwide use personality measures to select applicants for sales jobs or to assess incumbent sales employees. In the present dissertation, consisting of four independent studies, five approaches to strengthen the personality-sales performance linkage

  7. Strengthening the Connection between Community Service and Diversity

    Science.gov (United States)

    Roper, Larry D.

    2012-01-01

    Educators often treat community service and diversity as distinct areas. The author argues that educators should seize upon the intersection of these two areas in order to strengthen students' capacity to engage with each.

  8. Hamiltonian formulation of bond graphs

    NARCIS (Netherlands)

    Golo, Goran; Schaft, van der Arjan; Breedveld, Peter C.; Maschke, Bernhard M.; Johansson, R.; Rantzer, A.

    2003-01-01

    This paper deals with the mathematical formulation of bond graphs. It is proven that the power continuous part of bond graphs, the junction structure, can be associated with a Dirac structure and that the equations describing a bond graph model correspond to a port Hamiltonian system. The conditions

  9. Investigation on Strength Parameters of Interlocking Hollow Block Strengthened with Steel Fibres

    Directory of Open Access Journals (Sweden)

    Sarath P

    2015-08-01

    Full Text Available This work introduces a specially designed hollow block in such a way that the bonding was achieved by interlocking. The block provides facility for concealing electrical conduit, water and sewer pipes wherever so desired without causing much damage to the block. Proper surface finish was achieved by M10 mix. In order to get a finished surface several trial mixes were tested. The respective blocks were casted with and without steel fibres and the test results were compared. A comparative study of strength parameters is to be executed with respect to solid concrete block and concrete hollow block. Hollow block strengthened with steel fibre can be effectively used as load bearing wall.

  10. Failure Load Test of a CFRP Strengthened Railway Bridge in Oumlrnskoumlldsvik, Sweden

    DEFF Research Database (Denmark)

    Täljsten, Björn; Bergström, Markus; Carolin, Anders

    2009-01-01

    using carbon fiber reinforced polymer (CFRP) rectangular rods epoxy bonded in sawed up slots, e.g., near surface mounted reinforcement. The strengthening was very successful and resulted in a desired shear failure when the bridge was loaded to failure. The load-carrying capacity in bending for the...... steel reinforcement by approximately 10%, and increased the height of the compressed zone by 100 mm. When the shear failure occurred, the utilization of the compression concrete and CFRP rods were 100 and 87.5%, respectively. This indicates that a bending failure indeed was about to occur, even though......The results obtained when performing a load test to failure of an existing structure are valuable when assessing calculation models, updating finite element models, and investigating the true structural behavior. In this paper a destructive testing and monitoring of a railway bridge in Örnsköldsvik...

  11. Evidence for Interfacial Halogen Bonding.

    Science.gov (United States)

    Swords, Wesley B; Simon, Sarah J C; Parlane, Fraser G L; Dean, Rebecca K; Kellett, Cameron W; Hu, Ke; Meyer, Gerald J; Berlinguette, Curtis P

    2016-05-10

    A homologous series of donor-π-acceptor dyes was synthesized, differing only in the identity of the halogen substituents about the triphenylamine (TPA; donor) portion of each molecule. Each Dye-X (X=F, Cl, Br, and I) was immobilized on a TiO2 surface to investigate how the halogen substituents affect the reaction between the light-induced charge-separated state, TiO2 (e(-) )/Dye-X(+) , with iodide in solution. Transient absorption spectroscopy showed progressively faster reactivity towards nucleophilic iodide with more polarizable halogen substituents: Dye-F < Dye-Cl < Dye-Br < Dye-I. Given that all other structural and electronic properties for the series are held at parity, with the exception of an increasingly larger electropositive σ-hole on the heavier halogens, the differences in dye regeneration kinetics for Dye-Cl, Dye-Br, and Dye-I are ascribed to the extent of halogen bonding with the nucleophilic solution species. PMID:27060916

  12. Progress Report

    DEFF Research Database (Denmark)

    Duer, Karsten

    1999-01-01

    Progress report describing the work carried out by the Danish participant in the ALTSET project in the period January 1999 to July 1999.......Progress report describing the work carried out by the Danish participant in the ALTSET project in the period January 1999 to July 1999....

  13. Engineering, global health, and inclusive innovation: focus on partnership, system strengthening, and local impact for SDGs.

    Science.gov (United States)

    Clifford, Katie L; Zaman, Muhammad H

    2016-01-01

    The recent drafting of the Sustainable Development Goals challenges the research community to rethink the traditional approach to global health and provides the opportunity for science, technology, engineering, and mathematical (STEM) disciplines, particularly engineering, to demonstrate their benefit to the field. Higher education offers a platform for engineering to intersect with global health research through interdisciplinary partnerships among international universities that provide excellence in education, attract nontraditional STEM students, and foster a sense of innovation. However, a traditional lack of engineering-global health collaborations, as well as limited faculty and inadequate STEM research funding in low-income countries, has stifled progress. Still, the impact of higher education on development efforts holds great potential. This value will be realized in low-income countries through strengthening local capacity, supporting innovation through educational initiatives, and encouraging the inclusion of women and minorities in STEM programs. Current international university-level partnerships are working towards integrating engineering into global health research and strengthening STEM innovation among universities in low-income countries, but more can be done. Global health research informs sustainable development, and through integrating engineering into research efforts through university partnerships, we can accelerate progress and work towards a healthier future for all. PMID:26790462

  14. Engineering, global health, and inclusive innovation: focus on partnership, system strengthening, and local impact for SDGs

    Directory of Open Access Journals (Sweden)

    Katie L. Clifford

    2016-01-01

    Full Text Available The recent drafting of the Sustainable Development Goals challenges the research community to rethink the traditional approach to global health and provides the opportunity for science, technology, engineering, and mathematical (STEM disciplines, particularly engineering, to demonstrate their benefit to the field. Higher education offers a platform for engineering to intersect with global health research through interdisciplinary partnerships among international universities that provide excellence in education, attract nontraditional STEM students, and foster a sense of innovation. However, a traditional lack of engineering–global health collaborations, as well as limited faculty and inadequate STEM research funding in low-income countries, has stifled progress. Still, the impact of higher education on development efforts holds great potential. This value will be realized in low-income countries through strengthening local capacity, supporting innovation through educational initiatives, and encouraging the inclusion of women and minorities in STEM programs. Current international university-level partnerships are working towards integrating engineering into global health research and strengthening STEM innovation among universities in low-income countries, but more can be done. Global health research informs sustainable development, and through integrating engineering into research efforts through university partnerships, we can accelerate progress and work towards a healthier future for all.

  15. Post-compressed plates for strengthening preloaded reinforced concretecolumns

    OpenAIRE

    Wang, Lu; 王璐

    2013-01-01

    Reinforced concrete (RC) columns are the primary load-bearing structural components in buildings. Over time these columns may need to be repaired or strengthened either due to defective construction, having higher loads than those foreseen in the initial design of the structure, or as a result of material deterioration or accidental damage. Three external strengthening methods, namely steel jacketing, concrete jacketing and composite jacketing, are commonly adopted for upgrading the ultimate...

  16. Strengthening of a railway bridge with NSMR and CFRP tubes

    DEFF Research Database (Denmark)

    Täljsten, Björn; Bennitz, Anders; Danielsson, Georg

    2008-01-01

    Strengthening of structures with CFRP is today considered an accepted method to upgrade concrete structures. In this paper two different CFRP strengthening systems are combined to give extended service life to a Swedish double-trough-double-track railway bridge, constructed in concrete with a 10 ....... Sensors on bars and tubes display proofs of utilization of the CFRP while displacement sensors and strain gauges on the steel reinforcement due to the small loads in the service limit state show minor effect....

  17. Coefficient strengthening : a tool for formulating mixed integer programs

    OpenAIRE

    Andersen, Kent; Pochet, Yves

    2007-01-01

    Providing a good formulation is an important part of solving a mixed integer program. We suggest to measure the quality of a formulation by whether it is possible to strengthen the coefficients of the formulation. Sequentially strengthening coefficients can then be used as a tool for improving formulations. We believe this method could be useful for analyzing and producing tight formulations of problems that arise in practice. We illustrate the use of the approach on a problem in production s...

  18. Strengthening health professions regulation in Cambodia: a rapid assessment

    OpenAIRE

    Clarke, David; Duke, Jan; Wuliji, Tana; Smith, Alyson; Phuong, Keat; San, Un

    2016-01-01

    Background This paper describes a rapid assessment of Cambodia’s current system for regulating its health professions. The assessment forms part of a co-design process to set strategic priorities for strengthening health profession regulation to improve the quality and safety of health services. A health system approach for strengthening health professions’ regulation is underway and aims to support the Government of Cambodia’s plans for scaling up its health workforce, improving health servi...

  19. Unified model to predict flexural shear behavior of externally bonded RC beams

    International Nuclear Information System (INIS)

    Structural strengthening with externally bonded reinforcement is now recognized as a cost-effective, structurally sound and practically efficient method of rehabilitating deteriorating and damaged reinforced concrete beams. There is now an urgent need to develop a sound engineering basis which can predict the failure loads of all such strengthened beams in a reliable and consistent manner. Existing models to predict the behavior at ultimate of strengthened beams suffer from many limitations and weaknesses. This paper presents a unified global model, based on the Strut-and-Tie approach, to predict the failure loads of reinforced concrete beams strengthened for flexure and/or shear. This structural model is based on rational engineering principles, considers all the possible failure modes, and incorporates the load transfer mechanism bond to reflect the debonding phenomena which has a dominant influence on the failure process of plated beams. The model is validated against about 200 strengthened beam test reported in the literature and failing in flexure and/or shear, involving a large number of structural variables and steel, carbon and glass fiber reinforced polymer laminates as reinforcing medium. (author)

  20. Flexural rigidity evolvement laws of reinforced concrete beams strengthened with carbon fiber laminates

    Institute of Scientific and Technical Information of China (English)

    NIU Peng-zhi; HUANG Pei-yan; DENG Jun; HAN Qiang

    2007-01-01

    Extensive research has shown that externally bonded carbon fiber reinforced polymer (CFRP) laminates are particularly suitable for improving the fatigue behavior of reinforced concrete (RC) beams. This paper presents the research on flexural rigidity evolvement laws by testing 14 simple-supported RC beams strengthened with carbon fiber laminates (CFL) under cyclic load, and 2 under monotone load as a reference. The cyclic load tests revealed the peak load applied onto the surface of a supported RC beam strengthened with CFL is linear to the logarithm of its fatigue life, and the flexural rigidity evolvement undergoes three distinct phases: a rapid decrease from the start to about 5% of the fatigue life; an even development from 5% to about 99% of the fatigue life; and a succedent rapid decrease to failure. When the ratio of fatigue cycles to the fatigue life is within 0.05 to 0.99, the flexural rigidity varies linearly with the ratio. The peak load does not affect the flexural rigidity evolvement if it is not high enough to make the main reinforcements yield. The dependences of the flexural rigidity of specimens formed in the same group upon their fatigue cycles normalized by fatigue life are almost coincident. This implies the flexural rigidity may be a material parameter independent of the stress level. These relationships of flexural rigidity to fatigue cycles, and fatigue life may be able to provide some hints for fatigue design and fatigue life evaluation of RC member strengthened with CFL; nevertheless the findings still need verifying by more experiments.

  1. ASEAN+3 Bond Market Guides

    OpenAIRE

    Asian Development Bank (ADB)

    2012-01-01

    The ASEAN+3 Bond Market Guide contains the comprehensive reports of the ASEAN+3 Bond Market Forum Sub-Forum 1 (SF1) and Sub-Forum 2 (SF2). The SF1 report (Volume 1) analyzes the harmonization and standardization of the existing bond markets in the ASEAN+3. It also contains the individual market guides of 11 economies under the ASEAN+3 Bond Market Forum (ABMF). The SF2 report (Volume 2) provides an overview of the ASEAN+3 bond markets and their infrastructures, as well as issues confronted by ...

  2. Optimal Investment in Structured Bonds

    DEFF Research Database (Denmark)

    Jessen, Pernille; Jørgensen, Peter Løchte

    The paper examines the role of structured bonds in the optimal portfolio of a small retail investor. We consider the typical structured bond essentially repacking an exotic option and a zero coupon bond, i.e. an investment with portfolio insurance. The optimal portfolio is found when the investment...... opportunities consist of a risky reference fund, a risk-free asset and a structured bond. Key model elements are the trading strategy and utility function of the investor. Our numerical results indicate structured bonds do have basis for consideration in the optimal portfolio. The product holdings are...

  3. Diffusion bonding between ODS ferritic steel and F82H steel for fusion applications

    International Nuclear Information System (INIS)

    Diffusion bonding techniques were employed to join high Cr oxide dispersion strengthened (ODS) ferritic steel (Fe–15Cr–2W–0.2Ti–0.35Y2O3) and F82H steel under uni-axial hydrostatic pressure using a high vacuum hot press, and the microstructure and mechanical properties of the joints were investigated. The dissimilar joints were bonded by solid-state diffusion bonding (SSDB) and liquid phase diffusion bonding (LPDB). After bonding process, heat treatments were conducted to utilize the phase transformation of F82H steel for recovering the martensitic structure. Tensile tests with miniaturized specimens were carried out to investigate and compare the bonding strengths of each joint. Microstructure was observed for the bonding interface, and fracture mode was investigated after the tensile tests. LPDB joint of interfacial F82H steel fully recovered to martensite phase by post-joining heat treatments, while SSDB joint had ferrite phases at the interface even after heat treatment, which is considered to be due to decarburization of F82H steel during the bonding process. Therefore it is considered that the insert material plays a role as diffusion barrier of carbon during LPDB process. Microstructure observations and tensile tests of the joints revealed that the LPDB joints possess suitable tensile properties which are comparable to that of F82H steel. This indicates that LPDB is more promising method to bond ODS-FS and F82H steel than SSDB.

  4. Disassembly of irradiated lithium-bonded capsules containing vanadium alloy specimens

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Strain, R.V.

    1996-04-01

    Capsules containing vanadium alloy specimens from irradiation experiments in FFTF and EBR-II are being processed to remove the lithium bond and retrieve the specimens for testing. The work has progressed smoothly.

  5. Further Developments in Gold-stud Bump Bonding

    CERN Document Server

    Neher, C; Moskaleva, A; Pasner, J; Tripathi, M; Woods, M

    2012-01-01

    As silicon detectors in high energy physics experiments require increasingly complex assembly procedures, the availability of a wide variety of interconnect technologies provides more options for overcoming obstacles in generic R&D. Gold ball bonding has been a staple in the interconnect industry due to its ease of use and reliability. However, due to some limitations in the standard technique, alternate methods of gold-stud bonding are being developed. This paper presents recent progress and challenges faced in the development of double gold-stud bonding and 0.5 mil wire gold-stud bonding at the UC Davis Facility for Interconnect Technology. Advantages and limitations of each technique are analyzed to provide insight into potential applications for each method. Optimization of procedures and parameters is also presented.

  6. Further developments in gold-stud bump bonding

    Science.gov (United States)

    Neher, C.; Lander, R. L.; Moskaleva, A.; Pasner, J.; Tripathi, M.; Woods, M.

    2012-02-01

    As silicon detectors in high energy physics experiments require increasingly complex assembly procedures, the availability of a wide variety of interconnect technologies provides more options for overcoming obstacles in generic R&D. Gold ball bonding has been a staple in the interconnect industry due to its ease of use and reliability. However, due to some limitations in the standard technique, alternate methods of gold-stud bonding are being developed. This paper presents recent progress and challenges faced in the development of double gold-stud bonding and 0.5 mil wire gold-stud bonding at the UC Davis Facility for Interconnect Technology. Advantages and limitations of each technique are analyzed to provide insight into potential applications for each method. Optimization of procedures and parameters is also presented.

  7. Further developments in gold-stud bump bonding

    International Nuclear Information System (INIS)

    As silicon detectors in high energy physics experiments require increasingly complex assembly procedures, the availability of a wide variety of interconnect technologies provides more options for overcoming obstacles in generic R and D. Gold ball bonding has been a staple in the interconnect industry due to its ease of use and reliability. However, due to some limitations in the standard technique, alternate methods of gold-stud bonding are being developed. This paper presents recent progress and challenges faced in the development of double gold-stud bonding and 0.5 mil wire gold-stud bonding at the UC Davis Facility for Interconnect Technology. Advantages and limitations of each technique are analyzed to provide insight into potential applications for each method. Optimization of procedures and parameters is also presented.

  8. Hydrogen bonding and coordination bonding in the electronically excited states of the MOF Cu2 (L)2 (L=5-(4-pyridyl)tetrazole) CH2Cl2: A time-dependent density functional theory study

    International Nuclear Information System (INIS)

    The solvent-dependent luminescent metal-organic framework (MOF), Cu2(L)2·CH2Cl2 (L=5-(4-pyridyl)tetrazole), in the electronically excited states was studied using time-dependent density functional theory (TDDFT) method. Based on the analysis of the frontier molecular orbitals and electronic configuration, it revealed that the emission is attributed to a ligand-to-metal charge transfer (LMCT). Besides, we investigated the behavior of the hydrogen bonding and coordination bonding in the excited state S1 of Cu2(L)2·CH2Cl2. The results indicated that the strength of the hydrogen bonding N5⋯H39-C2 between the dichloromethane molecule and the tetrazole ligand was decreased in the S1 state, while the coordination bond Cu2-N8 was strengthened in the excited state. Moreover, we further demonstrated that the hydrogen bonding weakening and coordination bonding strengthening should be beneficial to the luminescent process of the MOF. Highlights: ► Solvent-dependent luminescent MOF was studied by TDDFT. ► Emission mechanism was a ligand to metal charge transition (LMCT). ► 1H NMR and binding energies indicate H-bond weakening in excited states. ► The coordination bonds become stronger in the excited states

  9. Effect of horizontal reinforcement in strengthening of masonry members

    International Nuclear Information System (INIS)

    An experimental research program was undertaken to ascertain the effectiveness of a new technique for strengthening masonry wall panels using steel strips on compressive and shear strength enhancement. The experimental work includes eight wall panels, four each for compressive and shear strength evaluation. This work was the phase I of extensive research project which include testing of strengthened masonry wall panels under monotonic load (Phase-I), static cyclic load (Phase-2) and dynamic load (Phase-3). The wall panels were strengthened with different steel strip arrangements, which consist of single/double face application of coarse and fine steel strip mesh with reduced spacing of horizontal strips. This paper investigates only the effectiveness of horizontal steel strips on strength enhancement. Four masonry wall panels are considered in two groups and in each group, one wall was retrofitted with coarse steel mesh on single face and on second wall fine steel mesh was applied on one side. Furthermore, test results of strengthened specimens are also compared with the un-strengthened specimen (REFE). The mechanisms by which load was carried were observed, varying from the initial, uncracked state, and the final, fully cracked state. The results demonstrate a quite significant increase in the compressive and shear capacity of strengthened panels as compared to REFE-panel. However, increase in the compressive strength of fine mesh above that of coarse mesh is negligible. The technique/approach is found quite viable for strengthening of masonry walls, for rehabilitation of old deteriorated buildings and unreinforced masonry structures in seismic zones. (author)

  10. Terahertz Vibrations and Hydrogen-Bonded Networks in Crystals

    Directory of Open Access Journals (Sweden)

    Masae Takahashi

    2014-03-01

    Full Text Available The development of terahertz technology in the last few decades has made it possible to obtain a clear terahertz (THz spectrum. THz vibrations clearly show the formation of weak bonds in crystals. The simultaneous progress in the code of first-principles calculations treating noncovalent interactions has established the position of THz spectroscopy as a powerful tool for detecting the weak bonding in crystals. In this review, we are going to introduce, briefly, the contribution of weak bonds in the construction of molecular crystals first, and then, we will review THz spectroscopy as a powerful tool for detecting the formation of weak bonds and will show the significant contribution of advanced computational codes in treating noncovalent interactions. From the second section, following the Introduction, to the seventh section, before the conclusions, we describe: (1 the crystal packing forces, the hydrogen-bonded networks and their contribution to the construction of organic crystals; (2 the THz vibrations observed in hydrogen-bonded molecules; (3 the computational methods for analyzing the THz vibrations of hydrogen-bonded molecules; (4 the dispersion correction and anharmonicity incorporated into the first-principles calculations and their effect on the peak assignment of the THz spectrum (5 the temperature dependence; and (6 the polarization dependence of the THz spectrum.

  11. Silicon carbide wafer bonding by modified surface activated bonding method

    Science.gov (United States)

    Suga, Tadatomo; Mu, Fengwen; Fujino, Masahisa; Takahashi, Yoshikazu; Nakazawa, Haruo; Iguchi, Kenichi

    2015-03-01

    4H-SiC wafer bonding has been achieved by the modified surface activated bonding (SAB) method without any chemical-clean treatment and high temperature annealing. Strong bonding between the SiC wafers with tensile strength greater than 32 MPa was demonstrated at room temperature under 5 kN force for 300 s. Almost the entire wafer has been bonded very well except a small peripheral region and few voids. The interface structure was analyzed to verify the bonding mechanism. It was found an amorphous layer existed as an intermediate layer at the interface. After annealing at 1273 K in vacuum for 1 h, the bonding tensile strength was still higher than 32 MPa. The interface changes after annealing were also studied. The results show that the thickness of the amorphous layer was reduced to half after annealing.

  12. The global health system: strengthening national health systems as the next step for global progress.

    OpenAIRE

    Julio Frenk

    2010-01-01

    In the second in a series of articles on the changing nature of global health institutions, Julio Frenk offers a framework to better understand national health systems and their role in global health.

  13. Strengthening programs in science, engineering and mathematics. Third annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Sandhu, S.S.

    1997-09-30

    The Division of Natural Sciences and Mathematics at Claflin College consists of the Departments of Biology, Chemistry, Computer Science, Physics, Engineering and Mathematics. It offers a variety of major and minor academic programs designed to meet the mission and objectives of the college. The division`s pursuit to achieve excellence in science education is adversely impacted by the poor academic preparation of entering students and the lack of equipment, facilities and research participation, required to impart adequate academic training and laboratory skills to the students. Funds were received from the US Department of Energy to improve the divisional facilities and laboratory equipment and establish mechanism at pre-college and college levels to increase (1) the pool of high school students who will enroll in Science and Mathematics courses (2) the pool of well qualified college freshmen who will seek careers in Science, Engineering and Mathematics (3) the graduation rate in Science,engineering and Mathematics at the undergraduate level and (4) the pool of well-qualified students who can successfully compete to enter the graduate schools of their choice in the fields of science, engineering, and mathematics. The strategies that were used to achieve the mentioned objectives include: (1) Improved Mentoring and Advisement, (2) Summer Science Camp for 7th and 8th graders, (3) Summer Research Internships for Claflin SEM Seniors, (4) Summer Internships for Rising High School Seniors, (5) Development of Mathematical Skills at Pre-college/Post-secondary Levels, (6) Expansion of Undergraduate Seminars, (7) Exposure of Undergraduates to Guest Speakers/Roll Models, (8) Visitations by Undergraduate Students to Graduate Schools, and (9) Expanded Academic Program in Environmental Chemistry.

  14. Strengthening national health laboratories in sub-Saharan Africa: a decade of remarkable progress

    OpenAIRE

    Alemnji, G. A.; Zeh, C.; Yao, K; Fonjungo, P. N.

    2014-01-01

    OBJECTIVES Efforts to combat the HIV/AIDS pandemic have underscored the fragile and neglected nature of some national health laboratories in Africa. In response, national and international partners and various governments have worked collaboratively over the last several years to build sustainable laboratory capacities within the continent. Key accomplishments reflecting this successful partnership include the establishment of the African-based World Health Organization Regional Office for Af...

  15. Bond length and local energy density property connections for non-transition-metal oxide-bonded interactions.

    Science.gov (United States)

    Gibbs, G V; Spackman, M A; Jayatilaka, D; Rosso, K M; Cox, D F

    2006-11-01

    For a variety of molecules and earth materials, the theoretical local kinetic energy density, G(r(c)), increases and the local potential energy density, V(r(c)), decreases as the M-O bond lengths (M = first- and second-row metal atoms bonded to O) decrease and the electron density, rho(r(c)), accumulates at the bond critical points, r(c). Despite the claim that the local kinetic energy density per electronic charge, G(r(c))/rho(r(c)), classifies bonded interactions as shared interactions when less than unity and closed-shell when greater, the ratio was found to increase from 0.5 to 2.5 au as the local electronic energy density, H(r(c)) = G(r(c)) + V(r(c)), decreases and becomes progressively more negative. The ratio appears to be a measure of the character of a given M-O bonded interaction, the greater the ratio, the larger the value of rho(r(c)), the smaller the coordination number of the M atom and the more shared the bonded interaction. H(r(c))/rho(r(c)) versus G(r(c))/rho(r(c)) scatter diagrams categorize the M-O bonded interactions into domains with the local electronic energy density per electron charge, H(r(c))/rho(r(c)), tending to decrease as the electronegativity differences for the bonded pairs of atoms decrease. The values of G(r(c)) and V(r(c)), estimated with a gradient-corrected electron gas theory expression and the local virial theorem, are in good agreement with theoretical values, particularly for the bonded interactions involving second-row M atoms. The agreement is poorer for shared C-O and N-O bonded interactions. PMID:17078623

  16. Credit default swaps, bond spreads and the bond market

    OpenAIRE

    Zhu, Meicheng

    2014-01-01

    With the rapid development of the credit default swap (CDS) market, the issue of how the introduction of CDSs affects the corporate bond market has been of particular interest to researchers and policy makers. This has been investigated in the literature from two perspectives. One is to examine the relationship between the CDS and the bond markets in price discovery, and the other is concerned with researching the CDS trading effects on bond spreads. Referring to the former approach, most rel...

  17. Solder extrusion pressure bonding process and bonded products produced thereby

    Science.gov (United States)

    Beavis, Leonard C.; Karnowsky, Maurice M.; Yost, Frederick G.

    1992-01-01

    Production of soldered joints which are highly reliable and capable of surviving 10,000 thermal cycles between about -40.degree. C. and 110.degree. C. Process involves interposing a thin layer of a metal solder composition between the metal surfaces of members to be bonded and applying heat and up to about 1000 psi compression pressure to the superposed members, in the presence of a reducing atmosphere, to extrude the major amount of the solder composition, contaminants including fluxing gases and air, from between the members being bonded, to form a very thin, strong intermetallic bonding layer having a thermal expansion tolerant with that of the bonded members.

  18. Avoiding silicon/glass bonding damage with fusion bonding method

    Institute of Scientific and Technical Information of China (English)

    Daohong Yang(杨道虹); Chen Xu(徐晨); Guangdi Shen(沈光地)

    2004-01-01

    A novel fusion bonding method between silicon and glass with Nd:YAG laser is described.This method overcomes the movable mechanical parts damage caused by the electrostatics force in micro-electronic machine-system(MEMS)device during the anodic bonding. The diameter of laser spot is 300 μm,the power of laser is 100 W,the laser velocity for bonding is 0.05 m/s,the average bonding tension is 6.3 MPa.It could distinctly reduce and eliminate the defects and damage,especially in movable sensitive mechanical parts of MEMS device.

  19. Strut Deformation in CFRP-Strengthened Reinforced Concrete Deep Beams

    Directory of Open Access Journals (Sweden)

    Mohammad Panjehpour

    2014-01-01

    Full Text Available Strut-and-tie model (STM method evolved as one of the most useful designs for shear critical structures and discontinuity regions (D-regions. It provides widespread applications in the design of deep beams as recommended by many codes. The estimation of bottle-shaped strut dimensions, as a main constituent of STM, is essential in design calculations. The application of carbon fibre reinforced polymer (CFRP as lightweight material with high tensile strength for strengthening D-regions is currently on the increase. However, the CFRP-strengthening of deep beam complicates the dimensions estimation of bottle-shaped strut. Therefore, this research aimed to investigate the effect of CFRP-strengthening on the deformation of RC strut in the design of deep beams. Two groups of specimens comprising six unstrengthened and six CFRP-strengthened RC deep beams with the shear span to the effective depth ratios (a/d of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 were constructed in this research. These beams were tested under four-point bending configuration. The deformation of struts was experimentally evaluated using the values of strain along and perpendicular to the strut centreline. The evaluation was made by the comparisons between unstrengthened and CFRP-strengthened struts regarding the widening and shortening. The key variables were a/d ratio and applied load level.

  20. Strut deformation in CFRP-strengthened reinforced concrete deep beams.

    Science.gov (United States)

    Panjehpour, Mohammad; Chai, Hwa Kian; Voo, Yen Lei

    2014-01-01

    Strut-and-tie model (STM) method evolved as one of the most useful designs for shear critical structures and discontinuity regions (D-regions). It provides widespread applications in the design of deep beams as recommended by many codes. The estimation of bottle-shaped strut dimensions, as a main constituent of STM, is essential in design calculations. The application of carbon fibre reinforced polymer (CFRP) as lightweight material with high tensile strength for strengthening D-regions is currently on the increase. However, the CFRP-strengthening of deep beam complicates the dimensions estimation of bottle-shaped strut. Therefore, this research aimed to investigate the effect of CFRP-strengthening on the deformation of RC strut in the design of deep beams. Two groups of specimens comprising six unstrengthened and six CFRP-strengthened RC deep beams with the shear span to the effective depth ratios (a/d) of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 were constructed in this research. These beams were tested under four-point bending configuration. The deformation of struts was experimentally evaluated using the values of strain along and perpendicular to the strut centreline. The evaluation was made by the comparisons between unstrengthened and CFRP-strengthened struts regarding the widening and shortening. The key variables were a/d ratio and applied load level. PMID:25197698

  1. Seismic strengthening of RC structures with exterior shear walls

    Indian Academy of Sciences (India)

    Hasan Kaplan; Salih Yilmaz; Nihat Cetinkaya; Ergin Atimtay

    2011-02-01

    Vulnerable buildings and their rehabilitation are important problems for earthquake regions. In recent decades the goal of building rehabilitation and strengthening has gained research attention and numerous techniques have been developed to achieve this. However, most of these strengthening techniques disturb the occupants, who must vacate the building during renovation. In this study, a new strengthening alternative for RC structures, namely exterior shear walls, has been experimentally investigated under reversed cyclic loading. Using the proposed technique, it is possible to strengthen structures without disturbing their users or vacating the building during renovation. In this technique, shear walls are installed in parallel to the building’s exterior sides. It has been observed that the usage of exterior shear walls considerably improve the capacity and sway stiffness of RC structures. The experimental results have also been compared and found to be in agreement with the numerical solutions. Post attached exterior shear walls behaved as a monolithic member of the structure. Design considerations for the exterior shear wall-strengthened buildings have also been discussed in the paper.

  2. Development of the strengthened safeguards system and the Additional Protocol

    International Nuclear Information System (INIS)

    For the past 30 years, the IAEA's safeguards system has contributed to the international non-proliferation regime by providing, inter alia, assurances regarding the peaceful uses of declared nuclear material. However, the discovery of a clandestine nuclear weapons program in Iraq in 1991 drew world-wide attention to the need to strengthen the system to address the absence of undeclared nuclear material and activities. Efforts to strengthen the IAEA's safeguards system began in 1991 and culminated in 1997 when the IAEA's Board of Governors approved a Model Protocol Additional to IAEA Safeguards Agreements which greatly expands the legal basis and scope of IAEA safeguards. Within this strengthened system it is expected that the IAEA be able to provide assurance not only of the absence of diversion of declared nuclear material but also on the absence of undeclared nuclear material and activities. This is to be done within a safeguards system that uses an optimal combination of all safeguards measures available, thereby achieving maximum effectiveness and efficiency within the available resources. The paper summarizes the evolution of the safeguards system, describes strengthened safeguards, reports on the status of implementing the strengthening measures, and outlines plans for integrating all available safeguards measures. (author)

  3. 19 CFR 113.12 - Bond application.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Bond application. 113.12 Section 113.12 Customs... CUSTOMS BONDS Bond Application and Approval of Bond § 113.12 Bond application. (a) Single entry bond application. In order to insure that the revenue is adequately protected the port director may require...

  4. LAMMPS Framework for Directional Dynamic Bonding

    DEFF Research Database (Denmark)

    2012-01-01

    We have extended the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) to support directional bonds and dynamic bonding. The framework supports stochastic formation of new bonds, breakage of existing bonds, and conversion between bond types. Bond formation can be controlled to li...

  5. Integration of European Bond Markets

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    2014-01-01

    I investigate the time variation in the integration of EU government bond markets. The integration is measured by the explanatory power of European factor portfolios for the individual bond markets for each year. The integration of the government bond markets is stronger for EMU than non-EMU memb......I investigate the time variation in the integration of EU government bond markets. The integration is measured by the explanatory power of European factor portfolios for the individual bond markets for each year. The integration of the government bond markets is stronger for EMU than non......-EMU members and stronger for old than new EU members. For EMU countries, the integration is weaker the lower the credit rating is. During the recent crisis periods, the integration is weaker, particularly for EMU countries....

  6. Additional disulfide bonds in insulin

    DEFF Research Database (Denmark)

    Vinther, Tine N; Pettersson, Ingrid; Huus, Kasper;

    2015-01-01

    -chain is flexible and can adapt multiple conformations. We examined how well disulfide bond predictions algorithms could identify disulfide bonds in this region of insulin. In order to identify stable insulin analogues with additional disulfide bonds, which could be expressed, the Cβ cut-off distance had...... higher yields in comparison to analogues with additional disulfide bonds that were more difficult to predict. In contrast, addition of the fourth disulfide bond rendered all analogues resistant to fibrillation under stress conditions and all stable analogues bound to the insulin receptor with picomolar...... predicts four additional four disulfide insulin analogues which could be expressed. Although the location of the additional disulfide bonds is only slightly shifted, this shift impacts both stability and activity of the resulting insulin analogues....

  7. RC Columns Strengthened with Novel CFRP Systems: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Annalisa Napoli

    2015-10-01

    Full Text Available This paper presents an experimental study undertaken to investigate the seismic behavior of full scale square (300 mm × 300 mm reinforced concrete (RC columns strengthened with novel systems employing carbon fiber-reinforced polymers (CFRP wraps. Experimental tests were carried out by subjecting specimens to a constant axial load and a cyclically reversed horizontal force applied in displacement control. Results have allowed for investigating the influence of the used strengthening systems on the specimens’ performance in terms of flexural strength and ductility as well as on the exhibited failure modes. The effectiveness of the studied techniques is also evaluated by comparing the performance of tested specimens with that of companion columns strengthened with alternative CFRP systems investigated in a previous experimental campaign.

  8. Strengthening of building structures using carbon composite materials

    Directory of Open Access Journals (Sweden)

    N.V. Paranicheva

    2010-03-01

    Full Text Available Currently, the question of ensuring the reliability of various building structures both at the stage of their construction and during operation is very urgent. There are a lot of different ways and constructive methods of structures strengthening. Аt the same time, traditional ways of concrete structures strengthening with steel reinforcement are such expensive, time consuming and in some cases require to interrupt the building operation. As an alternative, it is proposed to use composite materials based on high-strength carbon fibers.The authors consider the properties, advantages, disadvantages and the methods of application of these materials. This article presents results of a technical survey carried out in a public building in 2009. In this building the CFRP was used to strengthen concrete slabs, resting on the crossbar consoles. The calculation of the strength is adduced and the section selection is made. The authors demonstrate their conclusions about the feasibility of using carbon composite materials.

  9. Experimental Study on CFRP Strengthened Cold Formed Channel Columns

    Directory of Open Access Journals (Sweden)

    Sreedhar Kalavagunta

    2013-09-01

    Full Text Available Cold-formed steel members usually display local-global buckling interaction which strongly effects the structural strength of columns. Through strengthening web of the members this buckling can be controlled to some extent. In this investigation, Carbon Fibre Reinforced Polymers (CFRP is used for strengthening cold formed steel channel member. This paper presents compression tests of cold-formed plain and CFRP strengthened steel channel section columns. This paper also proposes a design method based on Direct Strength Method provisions specified in American Iron and Steel Institute (AISI, for determining the axial compression strength. Results obtained from the proposed design method are compared with experimental test data and are found to be in good agreement.

  10. Seismic Strengthening of Carpentry Joints in Traditional Timber Structures

    International Nuclear Information System (INIS)

    The static and dynamic behavior of timber structures largely depends on their connections. In traditional timber construction, elements are usually connected with carpentry joints based on contact pressure and friction, often with only minor reinforcement generically intended to avoid disassembling. In current practice, interventions for the upgrading of carpentry joints are mainly based on empirical knowledge according to tradition. Often they produce a general strengthening of the connection, but are not specific for the case of seismic action. Strengthening on heuristic bases may be only partially effective or possibly disproportioned. The behavior of the carpentry joints most used in roof structures is examined. The birdsmouth joint, connecting rafters to the tie beam, has been studied first, characterizing its behavior numerically and experimentally in monotonic and cyclic conditions. Other forms of the rafter-to-tie connection, the double notch joint and the case of parallel rafters, are discussed. Some general criteria for the seismic strengthening of these joints are presented

  11. Interfacial stresses in strengthened beam with shear cohesive zone model

    Indian Academy of Sciences (India)

    Zergua Abdesselam

    2015-02-01

    The failure of strengthened beams with fibre-reinforced polymer (FRP) materials is due to high stress concentration of FRP–concrete interface. Understanding the cause and mechanism of the debonding of the FRP plate and the prediction of the stress distribution at the concrete–FRP interface are important for more effective strengthening technique. This paper presents an analytical solution, based on Smith and Teng’s equations, for interfacial shear and normal stresses in reinforced concrete (RC) beams strengthened with a fibre reinforced polymer (FRP) plate. However, the shear stress–strain relationship is considered to be bilinear curve. The effects of the shear deformations are calculated in an RC beam, an adhesive layer, and an FRP plate. The results of parametric study are compared with those of Smith and Teng. They confirm the accuracy of the proposed approach in predicting both interfacial shear and normal stresses.

  12. Supersymmetric Valence Bond Solid States

    OpenAIRE

    Arovas, Daniel P.; Hasebe, Kazuki; Qi, Xiao-Liang; Zhang, Shou-Cheng

    2009-01-01

    In this work we investigate the supersymmetric version of the valence bond solid (SVBS) state. In one dimension, the SVBS states continuously interpolate between the valence bond states for integer and half-integer spin chains, and they generally describe superconducting valence bond liquid states. Spin and superconducting correlation functions can be computed exactly for these states, and their correlation lengths are equal at the supersymmetric point. In higher dimensions, the wave function...

  13. Mezzanine finance and corporate bonds

    OpenAIRE

    Libena TETREVOVA

    2009-01-01

    The article deals with the problems of mezzanine finance in relation to corporate bonds. Firstly, attention is paid to definition of mezzanine finance. The term mezzanine finance is used as a term for hybrid forms of financing that combine elements of debt and equity financing. Mezzanine finance represents an alternative form of financing corporate activities. Secondly, possible forms of mezzanine finance are characterized. We can say that special types of corporate bonds (convertible bonds a...

  14. Hydrogen Bonds Involving Metal Centers

    OpenAIRE

    Pavlović, G.; N. Raos

    2006-01-01

    Hydrogen bonds involving metal center as a hydrogen donor or hydrogen acceptor are only a specific type of metal-hydrogen interactions; it is therefore not easy to differentiate hydrogen bond from other metal-hydrogen interactions, especially agostic ones. The first part of the review is therefore devoted to the results of structural chemistry and molecular spectroscopy (NMR, IR), as a tool for differentiating hydrogen bondings from other hydrogen interactions. The classical examples of Pt···...

  15. Wafer bonding applications and technology

    CERN Document Server

    Gösele, Ulrich

    2004-01-01

    During the past decade direct wafer bonding has developed into a mature materials integration technology. This book presents state-of-the-art reviews of the most important applications of wafer bonding written by experts from industry and academia. The topics include bonding-based fabrication methods of silicon-on-insulator, photonic crystals, VCSELs, SiGe-based FETs, MEMS together with hybrid integration and laser lift-off. The non-specialist will learn about the basics of wafer bonding and its various application areas, while the researcher in the field will find up-to-date information about this fast-moving area, including relevant patent information.

  16. A simplified indirect bonding technique

    Directory of Open Access Journals (Sweden)

    Radha Katiyar

    2014-01-01

    Full Text Available With the advent of lingual orthodontics, indirect bonding technique has become an integral part of practice. It involves placement of brackets initially on the models and then their transfer to teeth with the help of transfer trays. Problems encountered with current indirect bonding techniques used are (1 the possibility of adhesive flash remaining around the base of the brackets which requires removal (2 longer time required for the adhesive to gain enough bond strength for secure tray removal. The new simplified indirect bonding technique presented here overcomes both these problems.

  17. Nuclear quantum effects of hydrogen bonds probed by tip-enhanced inelastic electron tunneling.

    Science.gov (United States)

    Guo, Jing; Lü, Jing-Tao; Feng, Yexin; Chen, Ji; Peng, Jinbo; Lin, Zeren; Meng, Xiangzhi; Wang, Zhichang; Li, Xin-Zheng; Wang, En-Ge; Jiang, Ying

    2016-04-15

    We report the quantitative assessment of nuclear quantum effects on the strength of a single hydrogen bond formed at a water-salt interface, using tip-enhanced inelastic electron tunneling spectroscopy based on a scanning tunneling microscope. The inelastic scattering cross section was resonantly enhanced by "gating" the frontier orbitals of water via a chlorine-terminated tip, so the hydrogen-bonding strength can be determined with high accuracy from the red shift in the oxygen-hydrogen stretching frequency of water. Isotopic substitution experiments combined with quantum simulations reveal that the anharmonic quantum fluctuations of hydrogen nuclei weaken the weak hydrogen bonds and strengthen the relatively strong ones. However, this trend can be completely reversed when a hydrogen bond is strongly coupled to the polar atomic sites of the surface. PMID:27081066

  18. STRENGTHENING OF TRENCH COVER PLATES FOR SWITCHGEAR BUILDING

    International Nuclear Information System (INIS)

    The objective of this calculation is to strengthen the existing trench cover plates of the Electrical Switchgear Building (BLDG 5010) of the Exploratory Studies Facility. A remodeling effort will change the portion of the facility that has the trenches for electrical cables to a craft/shop area. The users of the building will be using a forklift in this area (Clark CGP 30 forklift with a capacity of 3 tons). The trench covers require strengthening to support the wheel loads from the forklift. The output of this calculation will be sketches revising the floor plate details of DWG YMP-025-1-7007-ST103,2. (Details 4 and 5)

  19. New deformation model of grain boundary strengthening in polycrystalline metals

    International Nuclear Information System (INIS)

    A new model explaining grain boundary strengthening in polycrystalline metals and alloys by strain hardening due to localization of plastic deformation in narrow bands near grain boundaries is suggested. Occurrence of localized deformation is caused by different flow stresses in grains of different orientation. A new model takes into account the active role of stress concentrator, independence of the strengthening coefficient on deformation, influence of segregations. Successful use of the model suggested for explanation of rhenium effect in molybdenum and tungsten is alloys pointed out

  20. Reactive Bonding Film for Bonding Carbon Foam Through Metal Extrusion

    CERN Document Server

    Chertok, Maxwell; Irving, Michael; Neher, Christian; Tripathi, Mani; Wang, Ruby; Zheng, Gayle

    2016-01-01

    Future tracking detectors, such as those under development for the High Luminosity LHC, will require mechanical structures employing novel materials to reduce mass while providing excellent strength, thermal conductivity, and radiation tolerance. Adhesion methods for such materials are under study at present. This paper demonstrates the use of reactive bonding film as an adhesion method for bonding carbon foam.

  1. Digital Control of Bonding Force for Gold Wire Bonding Machine

    Directory of Open Access Journals (Sweden)

    Xiaochu Wang

    2013-01-01

    Full Text Available In order to digitally control the bonding force of a wire bonder precisely, this paper uses a DC solenoid as a force source, and by controlling the solenoid’s current, which causes the electromagnetic force, we can control the bonding force that capillary applies. The bonding force control system in this paper is composed of PC (Personal Computer and hypogyny MCU (Micro Controller Unit, which communicate using a RS485 interface. The digital value of a given bonding force is given by the PC to the MCU. By comparing the sampling current of the solenoid, and through PID regulation, D/A converter of the digital potentiometer and the solenoid driver circuit, the half-closed loop control system of bonding force is accomplished. Tuning of the PID parameters is accomplished with fuzzy adaptive control theory and simulated by Matlab simulink. The control system is tested by comparing the desired bonding force and the force actually applied and examming the relationship between bonding quality and bonding force.

  2. Bond behavior between glulam and GFRP’s using pullout direct tests

    OpenAIRE

    Jorge, Marco; Sena-Cruz, José; Branco, Jorge M.; Barros, Joaquim A. O.; Dalfré, Gláucia

    2011-01-01

    To evaluate the bond behavior between glulam and GFRP rods using the near-surface mounted (NSM) strengthening technique, an experimental program was carried out by means of direct pullout tests. In this experimental program three variables were analyzed: the GFRP type (2 types), the GFRP location/groove size (2 types) and the bond length (Lb=30 mm, 60 mm, 120 mm and 180 mm). The instrumentation includes the loaded and free end slips, as well as the pullout force. Thirty seven specimens were t...

  3. Strategy of Strengthening Social Capital of Farmer Group in Agricultural Development

    Directory of Open Access Journals (Sweden)

    Galih Mukti Annas Wibisono

    2016-06-01

    Full Text Available In the village, the agricultural development is not certainly oriented to the economic aspect. The social intervention is very important and very helpful for the citizens and the development of the agricultural itself. The purpose of this research is to analyze the social existence, the social influence, and also the systematic strategy that can strengthen the society in developing the agriculture. The method used in this research is the qualitative analysis with phenomenology approach. The qualitative analysis is conducted by the direct observation in the field and in-depth interviews with the respondents that are selected by the purposive sampling. The result shows that a society has formed the farmer organization to have mutual coordination among the members. However, there are some problems that occur on this organization. The values and norms begin to fade and have become the major problem. Another problem is the sense of trust among the citizens and the unoptimal social network utilization. The conclusion is, the Analytic Network Process (ANP shows that to make a progress of agricultural development, they need to strengthen the social relationship among the citizens to face all the problems that may occur.

  4. Multiple Bonds Between Metal Atoms

    CERN Document Server

    Cotton, F Albert; Walton, Richard A

    2006-01-01

    Provides a discussion of preparations, reactions, bonding, and physical properties for two of the d-block transition metals in groups 5-10. This title includes catalytic and chemotherapeutic applications, and discusses metal-metal bonds of orders 0.5 to 4 discussed in than 4000 compounds, with citations to approximately 2500 references.

  5. Bondings for tubular solar collectors

    International Nuclear Information System (INIS)

    We studied the following four models of constructing solar collectors: tubes bonded above the absorber plate, tubes bonded under the absorber plate tubes in-line with the absorber plate and bondless tubes in-line with the absorber plate. 2 refs, 6 figs

  6. Computational Chemistry of Adhesive Bonds

    Science.gov (United States)

    Phillips, Donald H.

    1999-01-01

    This investigation is intended to determine the electrical mechanical, and chemical properties of adhesive bonds at the molecular level. The initial determinations will be followed by investigations of the effects of environmental effects on the chemistry and properties of the bond layer.

  7. APPLICATION OF PRESTRESSED SHELLS TO STRENGTHEN STRIP FOUNDATIONS

    Directory of Open Access Journals (Sweden)

    Ter-Martirosjan Zaven Grigor'evich

    2012-10-01

    Full Text Available Effective method of strengthening of foundations of existing buildings by pre-stressed shells is considered in the paper. Advantages of the proposed strengthening method, its production technology and pre-conditions of its analysis are also presented. Presently, strengthening of ground foundations and foundations of buildings and structures is a relevant civil engineering challenge. It is driven by high intensity of restructuring and modernization of buildings and alteration of geological engineering conditions of the areas that are being built up. One of effective methods of strengthening of foundations of existing buildings represents arrangement of pre-stressed concrete shells with conventional steel or metal-free reinforcement. If compared with injection-based technologies, the proposed reinforcement method reduces the cost of construction work by 1.5 times, on average. Therefore, the per-unit cost of shell-based reinforcement of foundations is under 500 Russian roubles per 1 sq. m. of the building floor area. It is noteworthy that no restrictions are imposed on the operation of the building in the course of the above reconstruction, as the secluded backyard is the sole area that accommodates supplementary construction operations.

  8. Conceptual Precalculus: Strengthening Students' Quantitative and Covariational Reasoning

    Science.gov (United States)

    Madison, Bernard L.; Carlson, Marilyn; Oehrtman, Michael; Tallman, Michael

    2015-01-01

    Research over the past few decades points to ways precalculus and calculus courses can be strengthened to improve student learning in these courses. This research has informed the development of the Algebra and Precalculus Concept Readiness (APCR) and the Calculus Concept Readiness (CCR) assessments. In this article, the authors present three…

  9. Strategies to Strengthen Our Anti-Bias Practices.

    Science.gov (United States)

    Carter, Margie

    1998-01-01

    Shares examples of how child care center directors dealt with homosexual bias issues in their centers. Suggests the following four strategies when strengthening antibias practices: use inclusive language and images in parent and staff orientations; examine personnel policies; use staff and parent meetings to explore myths, fears, and conflicting…

  10. Strengthening Grief Support for Adolescents Coping with a Peer's Death

    Science.gov (United States)

    Balk, David E.; Zaengle, Donna; Corr, Charles A.

    2011-01-01

    This article offers suggestions for strengthening school-based grief support following an adolescent's death. Such interventions must be considered within the context of: (a) development during adolescence; (b) the role of peers in adolescent development; and (c) the fact that an adolescent peer's death is a non-normative life crisis in developed…

  11. Communication Concepts for Strengthening Family-School-Community Partnerships.

    Science.gov (United States)

    Swick, Kevin J.

    2003-01-01

    Explores topics related to how families, schools, and communities can use communication to strengthen their partnerships. Discusses how communication empowers participants in a shared-learning process, and explores how attitudes shape communication efforts. Examines the role of culture in the communication process, focusing on how cultural…

  12. State Council Resolutions on Further Strengthening Rural Education

    Science.gov (United States)

    Chinese Education and Society, 2005

    2005-01-01

    Several resolutions on strengthening work in rural education have been made in order to accelerate development of rural education in China, deepen reform of rural education, guarantee a well-off society, and harmonize rural and urban development. This article presents a detailed plan of actions for each resolution. The resolutions are enumerated…

  13. Strengthening Foster Parent-Adolescent Relationships through Filial Therapy

    Science.gov (United States)

    Capps, Jennifer E.

    2012-01-01

    The purpose of this article is to explore the application of filial therapy as a means of strengthening relationships between foster parents and adolescent foster children. Adolescents in foster care experience a number of placement disruptions and while a number of therapeutic interventions are implemented to assist adolescents in foster care,…

  14. Practice and Cognition to Strengthen College Students' Moral Education

    Science.gov (United States)

    Ren, Wanbin

    2009-01-01

    College students' ideological morality always is the hotspot concerned by various circles of the society, and to strengthen and improve the ideological and moral education in colleges, continually enhance the pertinence and actual effect of the moral education, help college students to dissolve their worldly confusion in moral culture, further…

  15. Strengthening At-Risk and Homeless Young Mothers and Children

    Science.gov (United States)

    Medeiros, Debra; Vaulton, Wendy

    2010-01-01

    The Strengthening At Risk and Homeless Young Mothers and Children Initiative, funded by the Conrad N. Hilton Foundation, aims to improve the housing, health, and development of homeless and at-risk young families. This article describes the services provided in four program sites (Pomona, CA; Antelope Valley, CA; Minneapolis, MN; and Chicago, IL)…

  16. Programs for Strengthening Families of State Prison Staff

    Science.gov (United States)

    Tripp, Paula J.

    2010-01-01

    This article describes "Training for Strong Families," a family strengthening program for officers working in the state prison system. The program was offered once per week on the same day and at the same time, and the sessions lasted 15-20 minutes. The new program included topics such as Budgeting 101, Relationships, and Stress Management.…

  17. Children's Books in Review: Books on Strengthening Family Ties.

    Science.gov (United States)

    Winfield, Evelyn T.

    1991-01-01

    Reviews children's books that emphasize the strengthening of family ties. Characters in the books realize the importance and influence of family relationships as they struggle with sibling rivalry, self-discovery, peer relationships, a search for heritage, adoption, and death. (SM)

  18. Engineered cementitious composites for strengthening masonry infilled reinforced concrete frames

    DEFF Research Database (Denmark)

    Dehghani, Ayoub; Nateghi-Alahi, Fariborz; Fischer, Gregor

    2015-01-01

    The results of the second part of a comprehensive experimental program, aimed at investigating the behavior of masonry infilled reinforced concrete (RC) frames strengthened with fiber reinforced engineered cementitious composites (ECC) used as an overlay on the masonry wall, are presented in this...

  19. Information and Communication Technologies for Health Systems Strengthening

    OpenAIRE

    Otto, Kate; Shekar, Meera; Christopher H. Herbst; Mohammed, Rianna

    2015-01-01

    Information and communication technologies (ICT) for health or eHealth solutions hold great potential for generating systemic efficiencies by strengthening five critical pillars of a health system: human resources for health, supply chain management, health care financing, governance and service delivery, and infrastructure. This report describes the changing landscape of eHealth initiativ...

  20. Strengthening Humanistic Perspectives across the Curriculum: A Project [Report].

    Science.gov (United States)

    To-Dutka, Julia; Spencer, Sharon

    Montclair (New Jersey) State College sought to develop a structure that would facilitate the strengthening of humanistic perspectives in its students and would enable students to see the connections between their academic studies and the complex aspects of the meaning of being human in a world that is increasingly fragmented. Six pairs of faculty…

  1. Hall–Petch and dislocation strengthening in graded nanostructured steel

    DEFF Research Database (Denmark)

    Zhang, Xiaodan; Hansen, Niels; Gao, Yukui;

    2012-01-01

    across boundaries increases to ∼65% of high angle boundaries. The coldrolled steel shows a low hardening rate at high strain and by assuming additive strength contributions from Hall–Petch and dislocation strengthening, the flow stress has been expressed by the relationship σ - σ0 = k2D-0.5av , where Dav...

  2. Torsional Strengthening of RC Beams Using GFRP Composites

    Science.gov (United States)

    Patel, Paresh V.; Jariwala, Vishnu H.; Purohit, Sharadkumar P.

    2016-06-01

    Fiber reinforced polymer as an external reinforcement is used extensively for axial, flexural and shear strengthening in structural systems. The strengthening of members subjected to torsion is recently being explored. The loading mechanism of beams located at the perimeter of buildings which carry loads from slabs, joists and beams from one side of the member generates torsion that are transferred from the beams to the columns. In this work an experimental investigation on the improvement of the torsional resistance of reinforced concrete beams using Glass Fiber Reinforced Polymer (GFRP) is presented. Total 24 RC beams have been cast in this work. Ten beams of dimension 150 mm × 150 mm × 1300 mm are subjected to pure torsion while fourteen beams of 150 mm × 150 mm × 1700 mm are subjected to combined torsion and bending. Two beams in each category are designated as control specimen and remaining beams are strengthened by GFRP wrapping of different configurations. Pure torsion on specimens is applied using specially fabricated support mechanism and universal testing machine. For applying combined torsion and bending a loading frame and test set up are fabricated. Measurements of angle of twist at regular interval of torque, torsion at first crack, and ultimate torque, are obtained for all specimens. Results of different wrapping configurations are compared for control and strengthened beams to suggest effective GFRP wrapping configuration.

  3. Specific Suggestions to Strengthen Relations with Latin America

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ In the two decades ahead, China's development will face a period of important strategic opportunities. While coping with big power relations, China needs to be pluralistic in external relations and economic and trade relations. Therefore, strengthening relations with the developing countries and promoting South South cooperation is in China's interest and an essential link to ensure China's rise in the new century.

  4. Effect of Chloride Content on Bond Behavior Between FRP and Concrete

    Institute of Scientific and Technical Information of China (English)

    潘金龙; 黄毅方; 邢锋

    2010-01-01

    For reinforced concrete structures located along the seaside, the penetration of chloride ions into concrete may be a threat to the durability of the structures. Experimental investigations were carried out to study the effect of chloride content on the bond behavior between concrete and fiber reinforced polymer (FRP) plates. Direct shear tests were conducted on the FRP strengthened concrete members. Before testing, the specimens were immersed in NaCl solutions with concentrations ranging from 3%—15% for di...

  5. Quantum Confinement in Hydrogen Bond

    CERN Document Server

    Santos, Carlos da Silva dos; Ricotta, Regina Maria

    2015-01-01

    In this work, the quantum confinement effect is proposed as the cause of the displacement of the vibrational spectrum of molecular groups that involve hydrogen bonds. In this approach the hydrogen bond imposes a space barrier to hydrogen and constrains its oscillatory motion. We studied the vibrational transitions through the Morse potential, for the NH and OH molecular groups inside macromolecules in situation of confinement (when hydrogen bonding is formed) and non-confinement (when there is no hydrogen bonding). The energies were obtained through the variational method with the trial wave functions obtained from Supersymmetric Quantum Mechanics (SQM) formalism. The results indicate that it is possible to distinguish the emission peaks related to the existence of the hydrogen bonds. These analytical results were satisfactorily compared with experimental results obtained from infrared spectroscopy.

  6. Roll bonding of strained aluminium

    DEFF Research Database (Denmark)

    Staun, Jakob M.

    2003-01-01

    This report investigates roll bonding of pre-strained (å ~ 4) aluminium sheets to produce high strain material from high purity aluminium (99.996%) and commercial pure aluminium (99.6%). The degree of bonding is investigated by optical microscopy and ultrasonic scanning. Under the right...... circumstances both materials show good bonding, but the high purity material is excluded because of recrystallisation and the resulting loss of mechanical properties. The effect of cross stacking and roll bonding pre-strained sheets of the commercial purity material is investigated and some dependence of the...... cross rolled volume fraction is found. To further asses this effect, and the anisotropy, it is necessary to acquire knowledge about both texture and microstructure, e.g. by TEM. Roll bonding of pre-strained aluminium is found to be a possible alternative to ARB in the quest for ultra-fine grained...

  7. Seismic evaluation and strengthening of Bohunice nuclear power plant structures

    International Nuclear Information System (INIS)

    A seismic assessment and strengthening investigation is being performed for selected structures at the Bohunice V1 Nuclear Power Plant in Slovakia. Structures covered in this paper include the reactor building complex and the emergency generator station. The emergency generator station is emphasized in the paper as work is nearly complete while work on the reactor building complex is ongoing at this time. Seismic evaluation and strengthening work is being performed by a cooperative effort of Siemens and EQE along with local contractors. Seismic input is the interim Review Level Earthquake (horizontal peak ground acceleration of 0.3 g). The Bohunice V1 reactor building complex is a WWER 4401230 nuclear power plant that was originally built in the mid-1970s but had extensive seismic upgrades in 1991. Siemens has performed three dimensional dynamic analyses of the reactor building complex to develop seismic demand in structural elements. EQE is assessing seismic capacities of structural elements and developing strengthening schemes, where needed. Based on recent seismic response analyses for the interim Review Level Earthquake which account for soil-structure interaction in a rigorous manner, the 1991 seismic upgrade has been found to be inadequate in both member/connection strength and in providing complete load paths to the foundation. Additional strengthening is being developed. The emergency generator station was built in the 1970s and is a two-story unreinforced brick masonry (URM) shear wall building above grade with a one story reinforced concrete shear wall basement below grade. Seismic analyses and testing of the URM walls has been performed to assess the need for building strengthening. Required structural strengthening for in-plane forces consists of revised and additional vertical steel framing and connections, stiffening of horizontal roof bracing, and steel connections between the roof and supporting walls and pointing of two interior transverse URM

  8. Dentin-bonding agents

    Directory of Open Access Journals (Sweden)

    João Carlos Gomes

    2008-01-01

    Full Text Available New dental restorative materials have been developed to meet not only the functional demands, but esthetics as well, and in the last few years an enormous range of new materials has appeared for use in dentistry. Among them, several adhesive systems, and different operative techniques for each group materials. Therefore, is indispensable for the professional to know about the properties, characteristics, and association of these materials with the dental structures, in order to select and use them correctly. Should conventional self-etching adhesive systems be used? This question encouraged this literature review to be conducted, with the aim of comparing the conventional adhesive systems with the self-etching systems and to look for scientific data that would help professionals to choose which adhesive system to use. When compared to conventional systems, it was noted that the self-etching systems show less sensitivity to technique, especially as regards errors the operator could commit. The self-etching systems, particularly the 2-step type, have shown equivalent values of bond strength, marginal microleakage and performance, therefore, will be an option for direct composite resin restorations in posterior teeth.

  9. EFFECT OF CORROSION ON BOND BEHAVIOR AND BENDING STRENGTH OF REINFORCED CONCRETE BEAMS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    There is growing concern for corrosion damage in reinforced concrete structures with several decades' service. Pullout tests and beam tests were carried out to study the effect of reinforcement corrosion on the bond behavior and bending strength of reinforced concrete beams. The bond strength of plain bars and concrete initially increases with increasing corrosion, then declines. The turning point depends on the cracking of the concrete cover. The bond strength of deformed bars and concrete increases with corrosion up to a certain amount, but with progressive increase in corrosion, the bond strength decreases, and the cracking of the concrete cover seems to have no effect on the bond strength. On the basis of test data, the bond strength coefficient recommended here, which, together with the bond strength of uncorroded steel bars and concrete, can be used to easily calculate the bond strength of corroded steel bars and concrete. The bond strength coefficient proposed in this paper can be used to study the bond stress-slip relationship of corroded steel bars and concrete. The bending strength of corroded reinforced concrete beams declines with increasing reinforcement corrosion. Decreased bending strength of corroded RC beam is due to reduction in steel bar cross section, reduction of yield strength of steel bar, and reduction of bond capacity between steel bar and concrete.

  10. Shear strength of orthodontic bracket bonding with GIC bonding agent after the application of CPP-ACPF paste

    Directory of Open Access Journals (Sweden)

    Melisa Budipramana

    2013-03-01

    Full Text Available Background: White spot lesion is a major problem during fixed orthodontic treatment. This problem can be solved by minimizing white spot lesion before the treatment and using a fluoride-releasing bonding agent. The application of casein phosphopeptidesamorphous calcium phospate fluoride (CPP-ACPF paste as remineralization agent before treatment and GIC as orthodontic bonding agent is expected to overcome this problem as well as to strengthen GIC bonding. Purpose: To measure the shear strength of fix orthodontic appliance using GIC bonding with CPP-ACPF application prior treatment. Methods: In this study, 50 extracted premolars were randomly divided into 2 groups: group 1 as treatment group and group II as control group that was not given CPPACPF pretreatment. After having been cut and put into acrylic device, the samples in group I were given pretreatment with CPP-ACPF paste on enamel surface for 2 minutes twice a day as instructed in product label for 14 days. Orthodontic brackets were bonded with GIC bonding agent on all samples in both groups as instructed in product label. Then, the shear strength was measured by Autograph Shimatzu with crosshead speed 0.5 mm/minute. The data was analyzed with Independent t-test. Results: The mean shear bond strength in treatment group was 19.22 ± 4.04 MPa and in control group was 12.97 ± 3.97 MPa. Independent t-test analysis showed that there was a significant difference between treatment and control group (p<0.05. Conclusion: CPP-ACPF pretreatment could increase GIC orthodontic bonding shear strength.Latar belakang: Lesi putih karies merupakan masalah utama selama perawatan dengan peranti cekat ortodonti. Hal ini dapat diatasi dengan cara mengurangi lesi putih sebelum perawatan dengan menggunakan bahan bonding yang mengandung fluorida. Aplikasi pasta casein phosphopeptides-amorphous calcium phospate fluoride (CPP-ACPF sebagai bahan remineralisasi sebelum perawatan dan bahan bonding GIC diharapkan dapat

  11. PetroChina's Obvious Progress in E&P

    Institute of Scientific and Technical Information of China (English)

    Zhao Xianzheng; Wang Heying

    2002-01-01

    @@ In 2002, PetroChina have made obvious progress since it began to carry forward integrated exploration and development, in the first half year, exploration and development have gained a series of achievements through optimizing deployment,deepening geological research, strengthening technological innovation, organizing elaborately and arranging carefully.

  12. Progress Report of Nuclear Facilities Remediation Projects in 2013

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    In 2013,five projects have been achieved a good progress through strengthening coordination and well-organization.1 Pilot project of radioactive solid waste retrieval and conditioning The hot commissioning of the project has been completed.Some radioactive solid waste was pretreated and conditioned during hot commissioning.The results of hot commissioning showed that data

  13. Strengthening mechanisms in nanostructured interstitial free steel deformed to high strain

    International Nuclear Information System (INIS)

    In this study, the strengthening mechanisms in nanostructured IF steel deformed to high strain by four-layer accumulative roll bonding (ARB) process at room temperature in absence and presence of SiC particles were investigated. Microstructural observations were performed by scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). The results indicated that the average grain size of the pure steel, composite, and nanocomposite was 95, 73, and 55 nm, respectively and the microstructures consisted of equiaxed grains. Also, with increasing the number of ARB cycles, the dislocation density of samples increased. The first cycle of ARB process had remarkable effect on the dislocation density. The value of dislocation density first rapidly increased, then dwindled, and finally saturated by further ARB cycles. The presence of SiC microparticles and nanoparticles in the IF steel matrix increased the dislocation density during the ARB process. On the other hand, dislocation density of the nanocomposite was higher than that of the composite. After first cycle, a significant increase observed in the yield strength, from 84 MPa to 609, 682, and 689 MPa for pure steel, composite, and nanocomposite, respectively, which was almost 7.3, 8.1, and 8.2 times greater than that of the initial sample. There was no perfect saturation in yield strength of the pure IF steel with increasing the number of ARB cycles. Finally, the contribution of individual mechanisms such as the grain refinement, dislocation, second phase, and precipitation in strengthening of the IF steel was evaluated. The contribution of grain refinement and precipitation to the improvement in yield strength was maximum (~67–72%) and minimum (~3.1–3.7%), respectively

  14. Strengthening mechanisms in nanostructured interstitial free steel deformed to high strain

    Energy Technology Data Exchange (ETDEWEB)

    Jamaati, Roohollah, E-mail: jamaati@nit.ac.ir; Toroghinejad, Mohammad Reza; Amirkhanlou, Sajjad; Edris, Hossein

    2015-07-15

    In this study, the strengthening mechanisms in nanostructured IF steel deformed to high strain by four-layer accumulative roll bonding (ARB) process at room temperature in absence and presence of SiC particles were investigated. Microstructural observations were performed by scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). The results indicated that the average grain size of the pure steel, composite, and nanocomposite was 95, 73, and 55 nm, respectively and the microstructures consisted of equiaxed grains. Also, with increasing the number of ARB cycles, the dislocation density of samples increased. The first cycle of ARB process had remarkable effect on the dislocation density. The value of dislocation density first rapidly increased, then dwindled, and finally saturated by further ARB cycles. The presence of SiC microparticles and nanoparticles in the IF steel matrix increased the dislocation density during the ARB process. On the other hand, dislocation density of the nanocomposite was higher than that of the composite. After first cycle, a significant increase observed in the yield strength, from 84 MPa to 609, 682, and 689 MPa for pure steel, composite, and nanocomposite, respectively, which was almost 7.3, 8.1, and 8.2 times greater than that of the initial sample. There was no perfect saturation in yield strength of the pure IF steel with increasing the number of ARB cycles. Finally, the contribution of individual mechanisms such as the grain refinement, dislocation, second phase, and precipitation in strengthening of the IF steel was evaluated. The contribution of grain refinement and precipitation to the improvement in yield strength was maximum (~67–72%) and minimum (~3.1–3.7%), respectively.

  15. Influence of receptor lateral mobility on adhesion strengthening between membranes containing LFA-3 and CD2.

    Science.gov (United States)

    Chan, P Y; Lawrence, M B; Dustin, M L; Ferguson, L M; Golan, D E; Springer, T A

    1991-10-01

    We have used an in vitro model system of glass-supported planar membranes to study the effects of lateral mobility of membrane-bound receptors on cell adhesion. Egg phosphatidylcholine (PC) bilayers were reconstituted with two anchorage isoforms of the adhesion molecule lymphocyte function-associated antigen 3 (LFA-3). The diffusion coefficient of glycosyl phosphatidylinositol (GPI)-anchored LFA-3 approached that of phospholipids in the bilayers, whereas the transmembrane (TM)-anchored isoform of LFA-3 was immobile. Both static and laminar flow assays were used to quantify the strength of adherence to the lipid bilayers of the T lymphoma cell line Jurkat that expresses the counter-receptor CD2. Cell adhesion was dependent on LFA-3 density and was more efficient on membranes containing the GPI isoform than the TM isoform. Kinetic measurements demonstrated an influence of contact time on the strength of adhesion to the GPI isoform at lower site densities (25-50 sites/microns2), showing that the mobility of LFA-3 is important in adhesion strengthening. At higher site densities (1,500 sites/microns2) and longer contact times (20 min), Jurkat cell binding to the TM and GPI isoforms of LFA-3 showed equivalent adhesion strengths, although adhesion strength of the GPI isoform developed twofold more rapidly than the TM isoform. Reduction of CD2 mobility on Jurkat cells at 5 degrees C greatly decreased the rate of adhesion strengthening with the TM isoform of LFA-3, resulting in a 30-fold difference between the two LFA-3 isoforms. Our results demonstrate that the ability of a membrane receptor and its membrane-bound counter-receptor to diffuse laterally enhances cell adhesion both by allowing accumulation of ligands in the cell contact area and by increasing the rate of receptor-ligand bond formation. PMID:1717480

  16. Cooperativity and Site-Selectivity of Intramolecular Hydrogen Bonds on the Fluorescence Quenching of Modified GFP Chromophores.

    Science.gov (United States)

    Chang, Deng-Hsiang; Ou, Chun-Lin; Hsu, Hung-Yu; Huang, Guan-Jhih; Kao, Chen-Yi; Liu, Yi-Hung; Peng, Shie-Ming; Diau, Eric Wei-Guang; Yang, Jye-Shane

    2015-12-18

    This paper provides the first example of experimentally characterized hydrogen-bond cooperativity on fluorescence quenching with a modified green fluorescence protein (GFP) chromophore that contains a 6-membered C═N···H-O and a 7-membered C═O···H-O intramolecular H-bonds. Variable-temperature (1)H NMR and electronic absorption and emission spectroscopies were used to elucidate the preference of intra- vs intermolecular H-bonding at different concentrations (1 mM and 10 μM), and X-ray crystal structures provide clues of possible intermolecular H-bonding modes. In the ground state, the 6-membered H-bond is significant but the 7-membered one is rather weak. However, fluorescence quenching is dominated by the 7-membered H-bond, indicating a strengthening of the H-bond in the excited state. The H-bonding effect is more pronounced in more polar solvents, and no intermediates were observed from femtosecond fluorescence decays. The fluorescence quenching is attributed to the occurrence of diabatic excited-state proton transfer. Cooperativity of the two intramolecular H-bonds on spectral shifts and fluorescence quenching is evidenced by comparing with both the single H-bonded and the non-H-bonded counterparts. The H-bond cooperativity does not belong to the conventional patterns of σ- and π-cooperativity but a new type of polarization interactions, which demonstrates the significant interplay of H-bonds for multiple H-bonding systems in the electronically excited states. PMID:26583964

  17. Physical Nature of Hydrogen Bond

    CERN Document Server

    Zhyganiuk, I V

    2015-01-01

    The physical nature and the correct definition of hydrogen bond (H-bond) are considered.\\,\\,The influence of H-bonds on the thermodynamic, kinetic, and spectroscopic properties of water is analyzed.\\,\\,The conventional model of H-bonds as sharply directed and saturated bridges between water molecules is incompatible with the behavior of the specific volume, evaporation heat, and self-diffusion and kinematic shear viscosity coefficients of water. On the other hand, it is shown that the variation of the dipole moment of a water molecule and the frequency shift of valence vibrations of a hydroxyl group can be totally explained in the framework of the electrostatic model of H-bond.\\,\\,At the same time, the temperature dependences of the heat capacity of water in the liquid and vapor states clearly testify to the existence of weak H-bonds.\\,\\,The analysis of a water dimer shows that the contribution of weak H-bonds to its ground state energy is approximately 4--5 times lower in comparison with the energy of electr...

  18. Tensile Bond Strength of Latex-Modified Bonded Concrete Overlays

    Science.gov (United States)

    Dubois, Cameron; Ramseyer, Chris

    2010-10-01

    The tensile bond strength of bonded concrete overlays was tested using the in-situ pull-off method described in ASTM C 1583 with the goal of determining whether adding latex to the mix design increases bond strength. One slab of ductile concrete (f'c > 12,000 psi) was cast with one half tined, i.e. roughened, and one half steel-troweled, i.e. smooth. The slab surface was sectioned off and overlay mixtures containing different latex contents cast in each section. Partial cores were drilled perpendicular to the surface through the overlay into the substrate. A tensile loading device applied a direct tensile load to each specimen and the load was increased until failure occurred. The tensile bond strength was then calculated for comparison between the specimens.

  19. The chemisorptive bond basic concepts

    CERN Document Server

    Clark, Alfred

    1974-01-01

    The Chemisorptive Bond: Basic Concepts describes the basic concepts of the chemisorptive bond on solid surfaces from the simple analogies with ordinary chemical bonds to the quantum-mechanical approaches.This book is composed of 10 chapters and begins with discussions of simple formulas for correlating measurable quantities in chemisorptions and catalysis. The succeeding chapters deal with theories based on quantum-mechanical principles that describe the mutual interactions of atoms of the solid and foreign atoms on the surface. The remaining chapters consider the possible arrangements

  20. Direct Bonded Pontic (Laporan Kasus

    Directory of Open Access Journals (Sweden)

    Suhandi Sidjaja

    2015-10-01

    Full Text Available Advanced science and technology in dentistry enable dental practitioners to modified she bonding techniques in tooth replacement. A pontic made of composite resin bonded to etched enamel of the adjacent teeth can be used in the replacement of one missing anterior tooth with a virgin or sowed adpicent tooth. The advantages of this technique include a one visit treatment, cow cost, good esthetics, less side effects and easy repair or rebounding. Clinical evaluation showed a high success rate therefore with a proper diagnosis and a perfect skill of the direct bonded technique this treatment can be used as an alternative restoration.

  1. Materials for nuclear diffusion-bonded compact heat exchangers

    International Nuclear Information System (INIS)

    This paper discusses the characteristics of materials used in the manufacture of diffusion bonded compact heat exchangers. Heatric have successfully developed a wide range of alloys tailored to meet process and customer requirements. This paper will focus on two materials of interest to the nuclear industry: dual certified SS316/316L stainless steel and nickel-based alloy Inconel 617. Dual certified SS316/316L is the alloy used most widely in the manufacture of Heatric's compact heat exchangers. Its excellent mechanical and corrosion resistance properties make it a good choice for use with many heat transfer media, including water, carbon dioxide, liquid sodium, and helium. As part of Heatric's continuing product development programme, work has been done to investigate strengthening mechanisms of the alloy; this paper will focus in particular on the effects of nitrogen addition. Another area of Heatric's programme is Alloy 617. This alloy has recently been developed for diffusion bonded compact heat exchanger for high temperature nuclear applications, such as the intermediate heat exchanger (IHX) for the very high temperature nuclear reactors for production of electricity, hydrogen and process heat. This paper will focus on the effects of diffusion bonding process and cooling rate on the properties of alloy 617. This paper also compares the properties and discusses the applications of these two alloys to compact heat exchangers for various nuclear processes. (author)

  2. SURFACE CAST IRON STRENGTHENING USING COMBINED LASER AND ULTRASONIC PROCESSING

    Directory of Open Access Journals (Sweden)

    O. Devojno

    2013-01-01

    Full Text Available The paper provides an analysis of ultrasonic surface plastic deformation and subsequent laser thermal strengthening of gray cast iron parts in the regime of hardening from a solid state with the purpose to obtain strengthened surface layers of bigger depth and less roughness of the processed surface. Program complex ANSYS 11.0 has been used for calculation of temperature fields induced by laser exposure.  The appropriate regime of laser processing without surface fusion has been selected on the basis of the applied complex. The possibility of displacement in the bottom boundary of α–γ-transformation temperature  for СЧ20 with 900 °С up to 800 °С is confirmed due to preliminary ultrasonic surface plastic deformation of the surface that allows to expand technological opportunities of laser quenching  of gray  cast iron from a solid state. 

  3. STRENGTHENING MECHANISMS IN Nb-Ti-V MICROALLOYED STEEL

    Directory of Open Access Journals (Sweden)

    Vinícius Lopes Vieira Martins

    2014-10-01

    Full Text Available Yield strength of Nb-Ti-V microalloyed steel has been investigated as a function of its microstructure obtained after industrial rolling on a hot strip mill. Optical (OM and transmission electron microscopy (TEM were used to reveal the ferrite grain structure, fine carbonitride precipitation and dislocation substructures. It was found that the effects of solid solution and grain size hardening were not sufficient to justify the results of tensile testing. Additional strengthening was attributed to carbonitride precipitation in austenite, interphase precipitation during transformation, and the formation of dislocations. All contributions of these microstructural features on mechanical property were estimated from empirical models available from literature. A global effect of both austenite and interphase carbonitride precipitation hardening was proposed. It was verified that yield strength calculated from cumulative effect of different strengthening mechanisms has presented good fitting with experimental tensile test.

  4. EMOTIONAL STRENGTHENING IN THE FAMILY: INTERVENTION FROM THE SCHOOL CONTEXT

    Directory of Open Access Journals (Sweden)

    Jael Alejandra Vargas Rubilar

    2012-06-01

    Full Text Available The psychological consequences from relational styles characterized by lack of affection and interactional mismanagement between family members can inhibit or block the attempt by members to achieve their full potential for healthy psy -chosocial development. In this context, emotional strengthening families would become a key condition for overcoming these dysfunctional patterns.The aim of this work is to show why psychoeducation and emotional stimula-tion can be particularly useful in the context of psychosocial risk due to poverty and present some strategies to approach such goal from the school environment. This approach is mainly focused on the strengthening of emotional resources in parents and primary caregivers to achieve a direct impact on the children’s emo-tional development.

  5. Development of oxide dispersion strengthened 2205 duplex stainless steel composite

    Directory of Open Access Journals (Sweden)

    Oladayo OLANIRAN

    2015-05-01

    Full Text Available Composites of duplex stainless steel were produced by oxide dispersion strengthening with comparatively improved mechanical properties by hot press sintering of partially stabilized Zirconia (PSZ, 3% yttria, mole fraction dispersion in 2205 duplex stainless steels. Ceramic oxide was added as reinforcement, while chromium (Cr and Nickel (Ni were incorporated to maintain the austenitic/ferritic phase balance of the duplex stainless steel. The powders and sintered were characterized in detail using scanning electron microscopy (SEM and X-ray diffraction (XRD. The microstructural evolution and phase formation during oxide dispersion strengthening of duplex stainless steel composites were investigated. The influence of composition variation of the reinforcements on the microstructural and corrosion behaviour in simulated mine water of the composites were investigated. In this manuscript, it was established that composition has great influence on the structure/properties relationship of the composites developed.

  6. Strengthening of Unreinforced Masonry Walls with Composite Materials

    Directory of Open Access Journals (Sweden)

    Ioana-Sorina Enţuc

    2004-01-01

    Full Text Available Unreinforced masonry (URM is considered one of the oldest construction materials being until the end of XIXth century, the basic material for: foundations, walls, columns, volts, staircases, floor joints, roofs, retaining walls, drainage channels, barrages, etc. Construction with URM elements posses a series of advantages such as: fire resistance, thermal an acoustic insulations between interior and outside spaces, humidity resistance. However the URM elements have some significant inconveniences such as: large self weight (heaviness causes cracks in the other elements of structures, reduced mechanical strengths in comparison with other traditional materials (steel and concrete, low tenacity, great manual labor consumptions, and vulnerability to earthquakes. Various factors cause deteriorations which must be overcome by strengthening solutions. Some strengthening solutions based on fiber reinforced polymers (FRP products applied directly on URM brick walls are presented in the paper.

  7. Generalized cosmological constraints on neutrino oscillations - Relaxed or strengthened

    International Nuclear Information System (INIS)

    I discuss cosmological constraints, based on BBN production of He-4, on electron-sterile neutrino oscillations proceeding after electron neutrino freeze-out. The general case of sterile neutrino state partially filled at the onset of oscillations is discussed 0 s s ≠ 0 has a two- fold effect on He-4: (a) it enhances the energy density, increasing the production of He-4 and strengthening BBN constraints on oscillations and (b) it suppresses the kinetic effects of oscillations on BBN, particularly neutrino spectrum distortion, thus decreasing He-4 overproduction and relaxing BBN constraints. The cosmological constraints depend on the interplay between the two effects: when the effect (a) dominates, the constraints are strengthened, while when the effect (b) dominates, the constraints are relaxed. (author)

  8. A novel CZT detector using strengthened electric field line anode

    Science.gov (United States)

    Fu, Jian-Qiang; Li, Yu-Lan; Zhang, Lan; Niu, Li-Bo; Jiang, Hao; Li, Yuan-Jing

    2014-12-01

    In this paper, we report on the design, simulation and testing of a novel CZT detector with an electrode named the Strengthened Electric Field Line Anode (SEFLA). The Strengthened Electric Field (SEF) technique and Single Polarity Charge Sensing (SPCS) technique are implemented. It could achieve the same performance as Coplanar Grid, Pixel Array CZT detectors but requires only a simple readout system. Geant4, Ansoft Maxwell and a self-developed Induced Current Calculator (ICC) package are used to develop an understanding of how the energy spectrum is formed, and the parameters of the detector are optimized. A prototype is fabricated. Experimental results demonstrate the effectiveness of this design. The test shows that the SEFLA detector achieves a FWHM of 6.0% @59.5 keV and 1.6% @662 keV, which matches well with the simulations.

  9. End Closure Joining of Ferritic-Martensitic and Oxide-Dispersion Strengthened Steel Cladding Tubes by Magnetic Pulse Welding

    Science.gov (United States)

    Lee, Jung-Gu; Park, Jin-Ju; Lee, Min-Ku; Rhee, Chang-Kyu; Kim, Tae-Kyu; Spirin, Alexey; Krutikov, Vasiliy; Paranin, Sergey

    2015-07-01

    The magnetic pulse welding (MPW) technique was employed for the end closure joining of fuel pin cladding tubes made of ferritic-martensitic (FM) steel and oxide-dispersion strengthened (ODS) steel. The technique is a solid-state impact joining process based on the electromagnetic force, similar to explosive welding. For a given set of optimal process parameters, e.g., the end-plug geometry, the rigid metallurgical bonding between the tube and end plug was obtained by high-velocity impact collision accompanied with surface jetting. The joint region showed a typical wavy morphology with a narrow grain boundary-like bonding interface. There was no evidence of even local melting, and only the limited grain refinement was observed in the vicinity of the bonding interface without destructing the original reinforcement microstructure of the FM-ODS steel, i.e., a fine grain structure with oxide dispersion. No leaks were detected during helium leakage test, and moreover, the rupture occurred in the cladding tube section without leaving any joint damage during internal pressure burst test. All of the results proved the integrity and durability of the MPWed joints and signified the great potential of this method of end closure joining for advanced fast reactor fuel pin fabrication.

  10. Reaction-bonded silicon nitride

    International Nuclear Information System (INIS)

    Reaction-bonded silicon nitride (RBSN) has been characterized. The oxidation behaviour in air up to 15000C and 3000 h and the effects of static and cyclic oxidation on room-temperature strength have been studied. (orig./IHOE)

  11. Optimal Investment in Structured Bonds

    DEFF Research Database (Denmark)

    Jessen, Pernille; Jørgensen, Peter Løchte

    2012-01-01

    of the article is to provide possible explanations for the puzzle of why small retail investors hold structured bonds. The investment universe consists of a stock index, a risk-free bank account, and a structured bond containing an option written on another index. We apply expected utility......Retail structured products regularly receive much criticism from financial experts but seem to remain popular with investors. This article considers a generic structured product: the principal-protected index-linked note (structured bond), which resembles a portfolio insurance contract. The purpose...... maximization and consider different utility functions and trading strategies. Our results show that investors should include structured bonds in their optimal portfolio only if they cannot access the index underlying the option directly and only if the products then provide sufficient diversification to...

  12. Adhesives for orthodontic bracket bonding

    Directory of Open Access Journals (Sweden)

    Déborah Daniella Diniz Fonseca

    2010-04-01

    Full Text Available The advent of acid etching, introduced by Buonocore in 1955, brought the possibility of bonding between the bracket base and enamel, contributing to more esthetic and conservative orthodontics. This direct bracket bonding technique has brought benefits such as reduced cost and time in performing the treatment, as well as making it easier to perform oral hygiene. The aim of this study was to conduct a survey of published studies on orthodontic bracket bonding to dental enamel. It was verified that resin composites and glass ionomer are the most studied and researched materials for this purpose. Resin-modified glass ionomer, with its biocompatibility, capacity of releasing fluoride and no need for acid etching on the tooth structure, has become increasingly popular among dentists. However, due to the esthetic and mechanical properties of light polymerizable resin composite, it continues to be one of the adhesives of choice in the bracket bonding technique and its use is widely disseminated.

  13. Effect of an external electric field on the dissociation energy and the electron density properties: The case of the hydrogen bonded dimer HFHF

    OpenAIRE

    Mata, Ignasi; Molins Grau, Elíes; Alkorta, Ibon; Espinosa Hernández, Enrique

    2009-01-01

    The effect of a homogeneous external electric field parallel to the hydrogen bond in the FHFH dimer has been studied by theoretical methods. The quantum theory of atoms in molecules methodology has been used for analyzing the electron distribution of the dimer, calculated with different hydrogen bond distances and external field magnitudes. It is shown that an electric field in the opposite direction to the dipole moment of the system strengthens the interaction due to a larger mutual polariz...

  14. Strengthening of Structures Damaged by the Azores Earthquake of 1998

    OpenAIRE

    Aníbal Costa; António Arêde

    2004-01-01

    This paper addresses repair and strengthening techniques proposed for the rehabilitation of small buildings on Faial Island, Azores, hit and damaged by the Azores earthquake on 9 July 1998. A brief description is provided of the construction type and practice in the island, highlighting the main type of houses. Due to the lack of relevant information concerning construction material data, experimental tests were performed in situ, involving static and dynamic measurements. The experimental ca...

  15. Inventory of FRP strengthening methods in masonry structures

    OpenAIRE

    Islam, Rashadul

    2008-01-01

    Masonry structures are prone to extensive damage followed by failure and collapse when subjected to loads resulting from wind, earthquake and other natural or man-made events. Recent earthquakes and terrorist acts have clearly demonstrated that the development of effective and affordable strategies for the strengthening of masonry is urgently needed. As a response to these challenges, fiber-reinforced polymer (FRP) composites may offer technically and economically viable soluti...

  16. Seismic analysis and strengthening of Pico Island Churches

    OpenAIRE

    Antonio Arede; Anibal Costa; Domingos Moreira; Nuno Neves

    2012-01-01

    The proposed study addresses the development of an integrated strategy for modelling, experimental calibration, numerical analysis and seismic strengthening carried out in two churches of the Pico Island, Azores, namely the Bandeiras and the Madalena churches. Following an initial description of the observed damages resulting from the 1998 earthquake, the modelling option for the churches structures is outlined. Reference is made to the use of ambient vibration tests that led to the definitio...

  17. Strengthening families through early intervention in high HIV prevalence countries

    OpenAIRE

    Chandan, U.; Richter, L.

    2009-01-01

    Families have been at the forefront of the response to the HIV/AIDS epidemic in high-prevalence countries. They have also borne the greatest costs associated with the epidemic, including impoverishment, which has strained their capacity to care for vulnerable members. Within this context, there is consensus that strengthening the capacity of families to care for children is one of the most important strategies for mitigating the impacts of the HIV/AIDS epidemic on children's lives in high-pre...

  18. Seismic evaluation of old masonry buildings: performance and strengthening

    OpenAIRE

    Varum, H.; Vicente, R.; Rodrigues, H; Silva, J. A. R. Mendes da

    2006-01-01

    The concern and need to assess seismic vulnerability, particularly of the traditional masonry buildings under seismic actions is a key issue, that should be a priority in the mitigation of the seismic risk, definition of strengthening requirements needs and minimization of possible damages due to seismic actions, in the identification of critical buildings and safeguarding of built heritage. This paper provides information on the constructive and structural details of the tr...

  19. EMOTIONAL STRENGTHENING IN THE FAMILY: INTERVENTION FROM THE SCHOOL CONTEXT

    OpenAIRE

    Jael Alejandra Vargas Rubilar; Laura Beatriz Oros

    2012-01-01

    The psychological consequences from relational styles characterized by lack of affection and interactional mismanagement between family members can inhibit or block the attempt by members to achieve their full potential for healthy psy -chosocial development. In this context, emotional strengthening families would become a key condition for overcoming these dysfunctional patterns.The aim of this work is to show why psychoeducation and emotional stimula-tion can be particularly useful in the c...

  20. Strengthening of poor lime mortar with consolidation agents

    Czech Academy of Sciences Publication Activity Database

    Slížková, Zuzana; Frankeová, Dita; Drdácký, Miloš

    Glasgow: University of the West of Scotland, 2013 - (Hughes, J.) ISBN 978-1-903978-44-3. [Historic mortars conference /3./. Glasgow (GB), 11.09.2013-13.09.2013] R&D Projects: GA ČR(CZ) GA103/09/2067; GA MŠk(CZ) ED1.1.00/02.0060 Institutional support: RVO:68378297 Keywords : mortar * consolidation * strengthening * treatment * consolidant Subject RIV: JN - Civil Engineering

  1. Malaysia; Technical Assistance Report-Strengthening Outcome Based Budgeting

    OpenAIRE

    International Monetary Fund

    2015-01-01

    This Technical Assistance report reviews the reforms undertaken by the Government of Malaysia for strengthening outcome-based budgeting (OBB). OBB builds on the previous output-based modified budgeting system, which was in place for more than two decades. OBB aims to improve the efficiency, the performance, and the prioritization of expenditures by aligning national and ministerial outcomes with programs and budgetary resources and by integrating planning, budgeting, and evaluation. OBB has m...

  2. Project on strengthening of structures using advanced composites

    OpenAIRE

    Recuero, A.; Miravete, A.

    1997-01-01

    Restoration, strengthening and rehabilitation of buildings becomes one of the more interesting aspects of the use of composites. Construction industry has not yet accepted the wide structural use of these new materials because it does not know the advantages of composites in comparison with traditional materials, such as concrete or steel. Engineers involved in design and construction are conservative and resist to changes. They require codes and specifications, what makes that an entity shou...

  3. Learning Sealing: Traditional Knowledge Strengthening Awareness of Being Greenlandic Today

    OpenAIRE

    Rosendahl, Sally

    2013-01-01

    This thesis investigates in which ways learning ‘traditional’ knowledge such as seal hunting is a strengthening factor for the awareness of being Greenlandic today. It looks at knowledge transfer between one generation and the next as well as the role of knowledge transfer in the education system. Finally, the tension or interplay between possessing traditional knowledge and living as a modern people is discussed. Through primarily using qualitative research in the shape of interviews of ...

  4. Brand Heritage : Helping Strengthen the Brand Identity of Husqvarna Motorcycles

    OpenAIRE

    Gårdh, Victor

    2009-01-01

    Abstract: Purpose: The purpose of this thesis is to learn how brand heritage and retro brands can help HQM strengthen their brand identity. Background: Companies with a long history have a strategic choice to make re-garding the use of their heritage in marketing communications. Such companies also enjoy a history of interesting products, for which some may exist the possibility for a retro relaunch. Husqvarna is such a company, which made it interesting to find out how these two strategic to...

  5. Strengthen the Supervision over Pharmaceuticals via Modern Automatic Identification

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Fake pharmaceuticals inflicts severely upon people(?)~-s health through its circulation in markets.To strengthen the supervision of the pharmaceutical market,China is improving and is perfecting its national coding system in the field of pharmaceuticals. Bar-code tag and IC tag are available to the coding system.This paper summarizes the significance of IC tag to the supervision of pharmaceuticals and gives us a strategically general prospect of pharmaceutical supervision.

  6. Strengthening of nuclear power plant construction safety management

    International Nuclear Information System (INIS)

    The article describes the warning of the Fukushima nuclear accident, and analyzes the major nuclear safety issues in nuclear power development in China, problems in nuclear power plants under construction, and how to strengthen supervision and management in nuclear power construction. It also points out that the development of nuclear power must attach great importance to the safety, and nuclear power plant construction should strictly implement the principle of 'safety first and quality first'. (author)

  7. Development of oxide dispersion strengthened 2205 duplex stainless steel composite

    OpenAIRE

    Oladayo OLANIRAN; Peter Apata OLUBAMBI; Benjamin Omotayo ADEWUYI; Joseph Ajibade OMOTOYINBO; Ayodeji Ebenezar AFOLABI; Davies FOLORUNSO; Adekunle ADEGBOLA; Emanuel IGBAFEN

    2015-01-01

    Composites of duplex stainless steel were produced by oxide dispersion strengthening with comparatively improved mechanical properties by hot press sintering of partially stabilized Zirconia (PSZ, 3% yttria, mole fraction) dispersion in 2205 duplex stainless steels. Ceramic oxide was added as reinforcement, while chromium (Cr) and Nickel (Ni) were incorporated to maintain the austenitic/ferritic phase balance of the duplex stainless steel. The powders and sintered were characterized in detail...

  8. Shear Strengthening of Corbels with Carbon Fibre Reinforced Polymers (CFRP)

    OpenAIRE

    Nawaz, A.; Salimullah, K.; Shah, A; Ahmad, S.

    2010-01-01

    Corbels constitute what are known as “disturbed” regions in concrete structures, where typical shear failure may be anticipated on the grounds of small shear span-to-depth ratios. The concentration of stress induced by the weight of girders on the very small loadbearing areas in corbels often causes cracking in bridges and other structures. Little experimental research can be found in the literature on the shear strengthening of corbels. In the present study, nine such members were tested. Tw...

  9. Field of Dreams: Strengthening Health Policy Scholarship in Canada

    OpenAIRE

    Julia Abelson; Mita Giacomini; John Lavis; John Eyles

    2008-01-01

    This background paper was prepared to inform discussion at CHEPA's Health Policy Symposium Field of Dreams: Strengthening Health Policy Scholarship in Canada on November 2, 2007. We reflect on the characteristics of Canada's health policy community in relation to the larger and more mature international health policy community: its contributions, opportunities and constraints for growing into a well institutionalized Canadian academic field. Sources consulted in preparing this document includ...

  10. Flexural strengthening of masonry members using advanced cementitious materials

    OpenAIRE

    Barros, Joaquim A. O.; Esmaeeli, Esmaeel; Manning, Elizabeth; Häßler, D.

    2011-01-01

    Two different cement based fiber reinforced composites for the flexural strengthening of masonry beams under monotonic loading are studied. Steel Fiber Reinforced Self- Compacting Concrete (SFRSCC) with tensile strain-softening behavior, and PVA fiber reinforced cement based mortar (SHCC) with tensile Strain-Hardening were the developed composites. Both composites were applied on the tensile surface of masonry beams and the effectiveness of this technique for the flexural stren...

  11. Powder-metallurgy superalloy strengthened by a secondary gamma phase.

    Science.gov (United States)

    Kotval, P. S.

    1971-01-01

    Description of experiments in which prealloyed powders of superalloy compositions were consolidated by extrusion after the strengthening by precipitation of a body-centered tetragonal gamma secondary Ni3 Ta phase. Thin foil electron microscopy showed that the mechanical properties of the resultant powder-metallurgy product were correlated with its microstructure. The product exhibited high strength at 1200 F without loss of ductility, after thermomechanical treatment and aging.

  12. Animal-assisted intervention and social skills strengthening

    OpenAIRE

    Božič, Tjaša

    2014-01-01

    The diploma thesis describe animal-assisted interventions, more precisely, the significance of animal-assisted interventions for strengthening of social skills. Theoretical part includes a detailed presentation of the benefits of therapeutic dog in work with vulnerable populations. I focused on delimitation of the term animal-assisted interventions which includes animal-assisted therapy and animal-assisted activity and the differences and similarities between them. I continued with therapeuti...

  13. Strengthening Laboratory Management Towards Accreditation: The Lesotho experience

    OpenAIRE

    David Mothabeng; Talkmore Maruta; Mathabo Lebina; Kim Lewis; Joe Wanyoike; Yohannes Mengstu

    2011-01-01

    Introduction: The Lesotho Ministry of Health and Social Welfare’s (MOHSW) 5-year strategic plan, as well as their national laboratory policy and yearly operational plans, directly addresses issues of accreditation, indicating their commitment to fulfilling their mandate. As such, the MOHSW adopted the World Health Organization Regional Headquarters for Africa’s Stepwise Laboratory Quality Improvement Toward Accreditation (WHO–AFRO–SLIPTA) process and subsequently rolled out the Strengthening ...

  14. Strengthen the servant leadership to enhance the nurses’ job satisfaction

    Directory of Open Access Journals (Sweden)

    Yun-xia HAO

    2014-11-01

    Full Text Available Objective: Continue to improve and implement the service concept of "taking patients as the center" through enhancing nurses’ job satisfaction. Methods: Strengthen clinic functions of nursing department, which is guided by the demands of clinical nurses. Results: Clinical nurses’ job satisfaction keeps at a high level. Conclusion: Service-oriented mode of nursing management can make the nurses to keep good work experience and satisfaction.

  15. Strengthening Globalization's Invisible Hand: What Matters Most?

    OpenAIRE

    Siems, Thomas F.; Adam S Ratner

    2006-01-01

    In this paper, we investigate what matters most to sustaining strong economic growth in today's more globalized, knowledge economy. An examination of 2005-2006 statistical and survey data across 52 countries reveals that economic growth is driven mainly by developed and trustworthy financial markets, a well-educated and skilled workforce, and access to information and communications technologies. Moreover, we find that creditworthy financial markets are strengthened by free and open economies...

  16. Nonlinear Finite Element Analysis of FRP Strengthened Reinforced Concrete Beams

    Science.gov (United States)

    Sasmal, S.; Kalidoss, S.; Srinivas, V.

    2012-12-01

    This paper focuses on nonlinear analysis of parent and fiber reinforced polymer (FRP) strengthened reinforced concrete (RC) beam using general purpose finite element software, ANSYS. Further, it is aimed to investigate the suitability of different elements available in ANSYS library to represent FRP, epoxy and interface. 3-D structural RC solid element has been used to model concrete and truss element is employed for modeling the reinforcements. FRP has been modelled using 3-D membrane element and layered element with number of layers, epoxy is modelled using eight node brick element, and eight node layered solid shell is used to mathematically represent the concrete-FRP interface behavior. Initially, the validation of the numerical model for the efficacy of different elements (SOLID65 for concrete and LINK8 for reinforcement) and material models is carried out on the experimental beam reported in literature. The validated model, elements and material properties is used to evaluate the load-displacement and load-strain response behavior and crack patterns of the FRP strengthened RC beams. The numerical results indicated that significant improvement in the displacement in the strengthened RC beams with the advancement of cracks. The study shows that FRP with shell elements is recommended when single layer of FRP is used. When multi layered FRP is used, solid layered element can be a reasonably good choice whereas the epoxy matrix with linear solid element does not need further complicated model. Interfacial element makes the analysis minimally improved at the cost of complicated modeling issues and considerable computation time. Hence, for nonlinear analysis of usual strengthened structures, unless it is specifically required for, interface element may not be required and a full contact can be assumed at interface.

  17. Strengthening families to support children affected by HIV and AIDS.

    Science.gov (United States)

    Richter, Linda M; Sherr, Lorraine; Adato, Michele; Belsey, Mark; Chandan, Upjeet; Desmond, Chris; Drimie, Scott; Haour-Knipe, Mary; Hosegood, Victoria; Kimou, Jose; Madhavan, Sangeetha; Mathambo, Vuyiswa; Wakhweya, Angela

    2009-01-01

    This paper provides an overview of the arguments for the central role of families, defined very broadly, and we emphasise the importance of efforts to strengthen families to support children affected by HIV and AIDS. We draw on work conducted in the Joint Learning Initiative on Children and AIDS's Learning Group 1: Strengthening Families, as well as published data and empirical literature to provide the rationale for family strengthening. We close with the following recommendations for strengthening families to ameliorate the effects of HIV and AIDS on children. Firstly, a developmental approach to poverty is an essential feature of responses to protect children affected by HIV and AIDS, necessary to safeguard their human capital. For this reason, access to essential services, such as health and education, as well as basic income security, must be at the heart of national strategic approaches. Secondly, we need to ensure that support garnered for children is directed to families. Unless we adopt a family oriented approach, we will not be in a position to interrupt the cycle of infection, provide treatment to all who need it and enable affected individuals to be cared for by those who love and feel responsible for them. Thirdly, income transfers, in a variety of forms, are desperately needed and positively indicated by available research. Basic economic security will relieve the worst distress experienced by families and enable them to continue to invest in the health care and education of their children. Lastly, interventions are needed to support distressed families and prevent knock-on negative outcomes through programmes such as home visiting, and protection and enhancement of children's potential through early child development efforts. PMID:22380973

  18. Internet Communication: Does It Strengthen Local Voluntary Organizations?

    OpenAIRE

    Eimhjellen, Ivar Sognnæs

    2013-01-01

    Does communication through the Internet strengthen local voluntary organizations? This question is investigated by analyzing sustainability, vitality, and the use of the Internet by Norwegian local voluntary organizations. Using quantitative data, analyses show that the use of the Internet by Norwegian voluntary organizations is widespread. Primarily, organizations appreciate the technology for its one-way aspect of communication and information distribution, rather than for as...

  19. Structural strengthening with prestressed CFRP strips with gradient anchorage

    OpenAIRE

    Michels, Julien; Sena-Cruz, José; Czaderski, Christoph; Motavalli, Masoud

    2013-01-01

    This paper presents the principle and the application of an innovative anchorage technique for prestressed carbon fiber–reinforced polymer (CFRP) strips in structural strengthening. Additionally, large-scale static loading tests of retrofitted concrete beams are shown. The gradient anchorage, based on the adhesive’s ability to undergo accelerated curing at high temperatures, consists of a purely concrete-adhesive strip connection without any mechanical devices, such as bolts or plates. In a f...

  20. Fundamental indexation for bond markets

    OpenAIRE

    Marielle de Jong; Hongwen Wu

    2014-01-01

    Purpose – The purpose of this paper is to build alternative indices weighing using a measure of fundamental value rather than debt size. The official bond indices built to reflect general price trends are market weighted, meaning that the bonds are weighted by their debt size. The more indebted, the more weight in the index, which mechanically increments the investment risks that are inherent. Those market indices are shown to be return-to-risk inefficient in recent studies compared to indice...

  1. Hydrogen Bonds in Polymer Folding

    OpenAIRE

    Borg, J; Jensen, M. H.; K. Sneppen; Tiana, G.

    2000-01-01

    The thermodynamics of a homopolymeric chain with both Van der Waals and highly-directional hydrogen bond interaction is studied. The effect of hydrogen bonds is to reduce dramatically the entropy of low-lying states and to give raise to long-range order and to conformations displaying secondary structures. For compact polymers a transition is found between helix-rich states and low-entropy sheet-dominated states. The consequences of this transition for protein folding and, in particular, for ...

  2. Oxide dispersion strengthening of nickel electrodeposits for microsystem applications.

    Energy Technology Data Exchange (ETDEWEB)

    Janek, Richard P. (Owens Technology Inc., Palo Alto, CA); Kotula, Paul Gabriel; Buchheit, Thomas Edward; Michael, R. P.; Goods, Steven Howard

    2003-11-01

    Oxide dispersion strengthened nickel (ODS-Ni) electrodeposits were fabricated to net shape in a nickel sulfamate bath using the LIGA process. A 20 g/l charge of 10 nm Al{sub 2}O{sub 3} powder was suspended in the bath during electrodeposition to produce specimens containing an approximately 0.001-0.02 volume fraction dispersion of the alumina particulate. Mechanical properties are compared to baseline specimens fabricated using an identical sulfamate bath chemistry without the Al{sub 2}O{sub 3} powder charge. Results reveal that the as-deposited ODS-Ni exhibited significantly higher yield strength and ultimate tensile strength than the baseline material. This increase in as-deposited strength is attributed to Orowan strengthening. The ODS-Ni also showed improved retention of room temperature strength after annealing over a range of temperatures up to 600 C. Microscopy revealed that this resistance to anneal softening was due to an inhibition of grain growth in the presence of the oxide dispersion. Nanoindentation measurements revealed that the properties of the dispersion strengthened deposit were uniform through its thickness, even in narrow, high aspect ratio structures. At elevated temperatures, the strength of the ODS-Ni was approximately three times greater than that of the baseline material although with a significant reduction in hot ductility.

  3. Retrofitting Heritage Buildings by Strengthening or Using Seismic Isolation

    International Nuclear Information System (INIS)

    Many heritage buildings in the Mediterranean area include stone domes as a structural and architectural element. Present stage of these buildings often requires strengthening or retrofitting in order to increase their seismic resistance. Strengthening is possible by casting above existing dome a thin reinforced concrete shell with a support ring. It yields reduction of stresses and strains in the dome. This paper deals with examples of actual restoration and strengthening of three structures in Georgia, two of them damaged by an earthquake in 1991, (a temple in Nikortzminda and a synagogue in Oni, built in 11th and 19r century, respectively) and a mosque in Akhaltzikhe, built in 18th century. Retrofitting of these structures was aimed at preservation of initial geometry and appearance by creating composite (stone--reinforced concrete, or stone--shotcrete) structures, which were partially or fully hidden. Further improving of seismic response may be achieved by using hybrid seismic isolation decreasing the seismic forces and adding damping. A brief description of the design procedure for such cases is presented

  4. Retrofitting Heritage Buildings by Strengthening or Using Seismic Isolation

    Science.gov (United States)

    Danieli, Moshe; Bloch, Jacob; Ribakov, Yuri

    2008-07-01

    Many heritage buildings in the Mediterranean area include stone domes as a structural and architectural element. Present stage of these buildings often requires strengthening or retrofitting in order to increase their seismic resistance. Strengthening is possible by casting above existing dome a thin reinforced concrete shell with a support ring. It yields reduction of stresses and strains in the dome. This paper deals with examples of actual restoration and strengthening of three structures in Georgia, two of them damaged by an earthquake in 1991, (a temple in Nikortzminda and a synagogue in Oni, built in 11th and 19r century, respectively) and a mosque in Akhaltzikhe, built in 18th century. Retrofitting of these structures was aimed at preservation of initial geometry and appearance by creating composite (stone—reinforced concrete, or stone—shotcrete) structures, which were partially or fully hidden. Further improving of seismic response may be achieved by using hybrid seismic isolation decreasing the seismic forces and adding damping. A brief description of the design procedure for such cases is presented.

  5. Age Strengthening of Gray Cast Iron Phase III

    Energy Technology Data Exchange (ETDEWEB)

    Von L. Richards; Wayne Nicola

    2003-06-26

    The primary objective of this research is to identify the age strengthening mechanism in gray and ductile cast iron, and to quantify the parameters that control it. It is also to contribute to a new predictive model for gray and ductile iron strength and hardness. This work shows that age strengthening occurs on a sigmoidal-logarithmic scale in gray and ductile cast irons, to a statistically significant extent. This is similar to Avrami-Johnson-Mehl kinetics for phase transformations in metals. It occurs in both cupola-melted iron and induction melted iron. However, it does not happen in all compositions. We have developed some understanding of the process. Data suggests that nitrogen and nitride-forming trace elements have a significant role in the process, but that is yet not fully characterized. Also, the time dependence of the bulk hardness and strength increase, the nano-scale precipitation evidence from neutron scattering, differential scanning calorimetry results and matrix micro-hardness increase in ferrite all indicate that age strengthening occurs by a precipitation or pre-precipitate cluster formation mechanism.

  6. Strengthening of Aluminum Alloy 2219 by Thermo-mechanical Treatment

    Science.gov (United States)

    Li, Xifeng; Lei, Kun; Song, Peng; Liu, Xinqin; Zhang, Fei; Li, Jianfei; Chen, Jun

    2015-10-01

    Strengthening of aluminum alloy 2219 by thermo-mechanical treatment has been compared with artificial aging. Three simple deformation modes including pre-stretching, compression, and rolling have been used in thermo-mechanical treatment. The tensile strength, elongation, fracture feature, and precipitated phase have been investigated. The results show that the strengthening effect of thermo-mechanical treatment is better than the one of artificial aging. Especially, the yield strength significantly increases with a small decrease of elongation. When the specimen is pre-stretched to 8.0%, the yield strength reaches 385.0 MPa and increases by 22.2% in comparison to the one obtained in aging condition. The maximum tensile strength of 472.4 MPa is achieved with 4.0% thickness reduction by compression. The fracture morphology reveals locally ductile and brittle failure mechanism, while the coarse second-phase particles distribute on the fracture surface. The intermediate phases θ″ or θ' orthogonally precipitate in the matrix after thermo-mechanical treatment. As compared to artificial aging, the cold plastic deformation increases distribution homogeneity and the volume fraction of θ'' or θ' precipitates. These result in a better strengthening effect.

  7. Extreme Precipitation Strengthening in Ion-Implanted Nickel

    International Nuclear Information System (INIS)

    Precipitation strengthening of nickel was investigated using ion-implantation alloying and nanoindentation testing for particle separations in the nanometer range and volume fractions extending above 10O/O. Ion implantation of either oxygen alone or oxygen plus aluminum at room temperature was shown to produce substantial strengthening in the ion-treated layer, with yield strengths near 5 GPa in both cases. After annealing to 550''C the oxygen-alone layer loses much of the benefit, with its yield strength reduced to 1.2 GP but the dual ion-implanted layer retains a substantially enhanced yield strength of over 4 GPa. Examination by transmission electron f microscopy showed very fine dispersions of 1-5 nm diameter NiO and y-A1203 precipitates in the implanted layers before annealing. The heat treatment at 550''C induced ripening of the NiO particles to sizes ranging from 7 to 20 nm, whereas the more stable -A1203 precipitates were little changed. The extreme strengthening we observe is in semiquantitative agreement with predictions based on the application of dispersion-hardening theory to these microstructure

  8. Effect of CeO{sub 2} addition on thermal shock resistance of WC–12%Co coating deposited on ductile iron by electric contact surface strengthening

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Xiaoben [College of Mechanical Engineering, Donghua University, Shanghai 201620 (China); College of Mechanical Engineering, Shanghai Dianji University, Shanghai 200240 (China); Zhu, Shigen, E-mail: sgzhu@dhu.edu.cn [College of Mechanical Engineering, Donghua University, Shanghai 201620 (China); Engineering Research Center of Advanced Textile Machinery, Ministry of Education, Shanghai 201620 (China)

    2015-09-15

    Highlights: • WC–Co powders with CeO{sub 2} were deposited by electric contact strengthening (ECS). • ECS is based on electric resistive heating between the electrode and work piece. • WC–Co coating with CeO{sub 2} by ECS was metallurgically bonded to the substrate. • The addition of CeO{sub 2} could refine the coating microstructure and increase the microhardness. • By the proper addition of cerium oxide, the thermal shock performance was enhanced. - Abstract: The WC–12%Co powders with different contents of CeO{sub 2} (0.1–2 wt.%) were deposited on ductile iron by electric contact surface strengthening. The coatings with and without CeO{sub 2} were examined and tested for microstructural characteristic, phase structure, microhardness and thermal shock resistance. The comparison concluded that the proper addition of CeO{sub 2} could refine the microstructure of coatings and increase the microhardness of the coatings. By the small amount addition of cerium oxide (0.5 wt.%), the solid solution strengthening effect and grain boundaries strengthening effect would delay the time of crack formation and propagation in the coatings and enhance the thermal shock performance.

  9. Effect of CeO2 addition on thermal shock resistance of WC–12%Co coating deposited on ductile iron by electric contact surface strengthening

    International Nuclear Information System (INIS)

    Highlights: • WC–Co powders with CeO2 were deposited by electric contact strengthening (ECS). • ECS is based on electric resistive heating between the electrode and work piece. • WC–Co coating with CeO2 by ECS was metallurgically bonded to the substrate. • The addition of CeO2 could refine the coating microstructure and increase the microhardness. • By the proper addition of cerium oxide, the thermal shock performance was enhanced. - Abstract: The WC–12%Co powders with different contents of CeO2 (0.1–2 wt.%) were deposited on ductile iron by electric contact surface strengthening. The coatings with and without CeO2 were examined and tested for microstructural characteristic, phase structure, microhardness and thermal shock resistance. The comparison concluded that the proper addition of CeO2 could refine the microstructure of coatings and increase the microhardness of the coatings. By the small amount addition of cerium oxide (0.5 wt.%), the solid solution strengthening effect and grain boundaries strengthening effect would delay the time of crack formation and propagation in the coatings and enhance the thermal shock performance

  10. NDT evaluation of long-term bond durability of CFRP-structural systems applied to RC highway bridges

    Science.gov (United States)

    Crawford, Kenneth C.

    2016-03-01

    The long-term durability of CFRP structural systems applied to reinforced-concrete (RC) highway bridges is a function of the system bond behavior over time. The sustained structural load performance of strengthened bridges depends on the carbon fiber-reinforced polymer (CFRP) laminates remaining 100 % bonded to concrete bridge members. Periodic testing of the CFRP-concrete bond condition is necessary to sustain load performance. The objective of this paper is to present a non-destructive testing (NDT) method designed to evaluate the bond condition and long-term durability of CFRP laminate (plate) systems applied to RC highway bridges. Using the impact-echo principle, a mobile mechanical device using light impact hammers moving along the length of a bonded CFRP plate produces unique acoustic frequencies which are a function of existing CFRP plate-concrete bond conditions. The purpose of this method is to test and locate CFRP plates de-bonded from bridge structural members to identify associated deterioration in bridge load performance. Laboratory tests of this NDT device on a CFRP plate bonded to concrete with staged voids (de-laminations) produced different frequencies for bonded and de-bonded areas of the plate. The spectra (bands) of frequencies obtained in these tests show a correlation to the CFRP-concrete bond condition and identify bonded and de-bonded areas of the plate. The results of these tests indicate that this NDT impact machine, with design improvements, can potentially provide bridge engineers a means to rapidly evaluate long lengths of CFRP laminates applied to multiple highway bridges within a national transportation infrastructure.

  11. NDT evaluation of long-term bond durability of CFRP-structural systems applied to RC highway bridges

    Science.gov (United States)

    Crawford, Kenneth C.

    2016-06-01

    The long-term durability of CFRP structural systems applied to reinforced-concrete (RC) highway bridges is a function of the system bond behavior over time. The sustained structural load performance of strengthened bridges depends on the carbon fiber-reinforced polymer (CFRP) laminates remaining 100 % bonded to concrete bridge members. Periodic testing of the CFRP-concrete bond condition is necessary to sustain load performance. The objective of this paper is to present a non-destructive testing (NDT) method designed to evaluate the bond condition and long-term durability of CFRP laminate (plate) systems applied to RC highway bridges. Using the impact-echo principle, a mobile mechanical device using light impact hammers moving along the length of a bonded CFRP plate produces unique acoustic frequencies which are a function of existing CFRP plate-concrete bond conditions. The purpose of this method is to test and locate CFRP plates de-bonded from bridge structural members to identify associated deterioration in bridge load performance. Laboratory tests of this NDT device on a CFRP plate bonded to concrete with staged voids (de-laminations) produced different frequencies for bonded and de-bonded areas of the plate. The spectra (bands) of frequencies obtained in these tests show a correlation to the CFRP-concrete bond condition and identify bonded and de-bonded areas of the plate. The results of these tests indicate that this NDT impact machine, with design improvements, can potentially provide bridge engineers a means to rapidly evaluate long lengths of CFRP laminates applied to multiple highway bridges within a national transportation infrastructure.

  12. Strengthening health workforce capacity through work-based training

    Directory of Open Access Journals (Sweden)

    Matovu Joseph KB

    2013-01-01

    Full Text Available Abstract Background Although much attention has been given to increasing the number of health workers, less focus has been directed at developing models of training that address real-life workplace needs. Makerere University School of Public Health (MakSPH with funding support from the Centers for Disease Control and Prevention (CDC developed an eight-month modular, in-service work-based training program aimed at strengthening the capacity for monitoring and evaluation (M&E and continuous quality improvement (CQI in health service delivery. Methods This capacity building program, initiated in 2008, is offered to in-service health professionals working in Uganda. The purpose of the training is to strengthen the capacity to provide quality health services through hands-on training that allows for skills building with minimum work disruptions while encouraging greater involvement of other institutional staff to enhance continuity and sustainability. The hands-on training uses practical gaps and challenges at the workplace through a highly participatory process. Trainees work with other staff to design and implement ‘projects’ meant to address work-related priority problems, working closely with mentors. Trainees’ knowledge and skills are enhanced through short courses offered at specific intervals throughout the course. Results Overall, 143 trainees were admitted between 2008 and 2011. Of these, 120 (84% from 66 institutions completed the training successfully. Of the trainees, 37% were Social Scientists, 34% were Medical/Nursing/Clinical Officers, 5.8% were Statisticians, while 23% belonged to other professions. Majority of the trainees (80% were employed by Non-Government Organizations while 20% worked with the public health sector. Trainees implemented 66 projects which addressed issues such as improving access to health care services; reducing waiting time for patients; strengthening M&E systems; and improving data collection and

  13. Optimising hydrogen bonding in solid wood

    DEFF Research Database (Denmark)

    Engelund, Emil Tang

    2009-01-01

    The chemical bonds of wood are both covalent bonds within the wood polymers and hydrogen bonds within and between the polymers. Both types of bonds are responsible for the coherence, strength and stiffness of the material. The hydrogen bonds are more easily modified by changes in load, moisture and...... temperature distorting the internal bonding state. A problem arises when studying hydrogen bonding in wood since matched wood specimens of the same species will have very different internal bonding states. Thus, possible changes in the bonding state due to some applied treatment such as conditioning or...... maintaining 100 % moisture content of the wood. The hypothesis was that this would enable a fast stress relaxation as a result of reorganization of bonds, since moisture plasticizes the material and temperature promotes faster kinetics. Hereby, all past bond distortions caused by various moisture, temperature...

  14. Carbonate clumped isotope bond reordering and geospeedometry

    Science.gov (United States)

    Passey, Benjamin H.; Henkes, Gregory A.

    2012-10-01

    Carbonate clumped isotope thermometry is based on the preference of 13C and 18O to form bonds with each other. At elevated temperatures such bond ordering is susceptible to resetting by diffusion of C and O through the solid mineral lattice. This type of bond reordering has the potential to obscure primary paleoclimate information, but could also provide a basis for reconstructing shallow crustal temperatures and cooling rates. We determined Arrhenius parameters for solid-state reordering of C-O bonds in two different calcites through a series of laboratory heating experiments. We find that the calcites have different susceptibilities to solid-state reordering. Reaction progress follows a first order rate law in both calcites, but only after an initial period of non-first order reaction that we suggest relates to annealing of nonequilibrium defects when the calcites are first heated to experimental temperature. We show that the apparent equilibrium temperature equations (or "closure temperature" equations) for carbonate clumped isotope reordering are analogous Dodson's equations for first order loss of daughter isotopes. For each calcite, the sensitivity of apparent equilibrium temperature to cooling rate is sufficiently high for inference of cooling rates within a factor of ˜5 or better for cooling rates ranging from tens of degrees per day to a few degrees per million years. However, because the calcites have different susceptibilities to reordering, each calcite defines its own cooling rate-apparent equilibrium temperature relationship. The cooling rates of Carrara marble inferred from carbonate clumped isotope geospeedometry are 10-6-10-3 degrees per annum and are in broad agreement with rates inferred from thermochronometric methods. Cooling rates for 13C-depleted calcites from the late Neoproterozoic Doushantou cap carbonates in south China are on the order of 102-104 degrees per annum, consistent with rapid cooling following formation of these calcites by a

  15. Progress report

    International Nuclear Information System (INIS)

    Progress Report, covering the period up to the end of 1979 year, was sent to the IAEA according to the research agreement No. 1971 /CF. This work covered the following fields: preparation and dummy irradiation experiments with a new experimental capsule of ''CHOUCA-M'' type; measurement of temperature fields and design of specimen holders; measurement of neutron energy spectrum in the irradiation place in our experimental reactor of VVR-S type (Nuclear Research Institute) using a set of activation detectors; unification and calibration of the measurement of neutron fluence with the use of Fe, Cu, Mn-Mg and Co-Al monitors; development and improvement of the measuring apparatus and technique for the dynamic testing of pre-cracked specimens with determination of dynamic parameters of fracture mechanics; preparation and manufacture of testing specimens from the Japanese steels - forging, plate and weld metal; preparation of the irradiation capsule for assembling

  16. Simplified Model for Strengthening Design of Beam–Column Internal Joints in Reinforced Concrete Frames

    Directory of Open Access Journals (Sweden)

    Antonio Bossio

    2015-09-01

    Full Text Available The beam-column joints are very restricted areas in which the internal forces, generated by boundary elements, act on the concrete core and reinforcing bars with a very high gradient. They are the link between horizontal and vertical structural elements, and therefore, they are directly involved in the transfer of seismic forces. Thus, they are crucial to study the seismic behavior of reinforced concrete (RC structures. To fully understand the seismic performances and failure modes of beam-column joints in RC buildings, a simplified analytical model of joint behavior is proposed and theoretical simulations are performed. The aim of the model, focusing on internal perimetric joints, is to identify the strength hierarchy in terms of capacity for different failure modes (namely failure of cracked joint, bond failure of passing through bars, flexural/shear failures of columns or beams. It could represent a tool for the designers of new joints to quantify the performance of new structures, but also as a tool for the designers of external strengthening of existing joints in order to calculate the benefits of the retrofit and pushing the initial failure to a more desirable failure mode. Further, some experimental results of tests available in the scientific literature are reported, analyzed and compared.

  17. Shear crack propagation in MBC strengthened concrete beams”

    DEFF Research Database (Denmark)

    Täljsten, Björn; Blanksvärd, Thomas; Carolin, Anders

    2008-01-01

    thermal compatibility to the base concrete and are often sensitive to the surface nature and surrounding temperature. By using mineral based composites (MBC) some of these challenges can be overcome. MBC refers here to a cementitious bonding agent and a carbon FRP grid. This paper is a part of an ongoing......Repair and upgrading existing concrete structures using FRPs and an epoxy adhesive as the bonding agent has some disadvantages when it comes to compatibility to the base concrete. Epoxies are often restricted by regulations of use, have low permeability which may create freeze/thaw problems, poor...

  18. Hypoxia-induced force increase (HIFI) is a novel mechanism underlying the strengthening of labor contractions, produced by hypoxic stresses.

    Science.gov (United States)

    Alotaibi, Mohammed; Arrowsmith, Sarah; Wray, Susan

    2015-08-01

    For successful birth, contractions need to become progressively stronger. The underlying mechanisms are unknown, however. We have found that a novel mechanism, hypoxia-induced force increase (HIFI), is switched on selectively, at term, and is essential to strengthening contractions. HIFI is initiated as contractions cyclically reduce blood flow and produce repeated hypoxic stresses, with associated metabolic and transcriptomic changes. The increases in contractility are a long-lasting, oxytocin-independent, intrinsic mechanism present only in the full-term pregnant uterus. HIFI is inhibited by adenosine receptor antagonism and blockade of cyclooxygenase-2 signaling, and partially reproduced by brief episodes of acidic (but not alkalotic) pH. HIFI explains how labor can progress despite paradoxical metabolic challenge, and provides a new mechanistic target for the 1 in 10 women suffering dysfunctional labor because of poor contractions. PMID:26195731

  19. Halogen Bonding versus Hydrogen Bonding: A Molecular Orbital Perspective

    OpenAIRE

    Wolters, Lando P.; Bickelhaupt, F. Matthias

    2012-01-01

    We have carried out extensive computational analyses of the structure and bonding mechanism in trihalides DX⋅⋅⋅A− and the analogous hydrogen-bonded complexes DH⋅⋅⋅A− (D, X, A=F, Cl, Br, I) using relativistic density functional theory (DFT) at zeroth-order regular approximation ZORA-BP86/TZ2P. One purpose was to obtain a set of consistent data from which reliable trends in structure and stability can be inferred over a large range of systems. The main objective was to achieve a detailed unders...

  20. Bond-centered, bond-ordered stripes in doped antiferromagnets

    OpenAIRE

    Wrobel, P.; Maciag, A; Eder, R.

    2004-01-01

    Motivated by recent inelastic neutron scattering experiments on cuprates, we discuss the formation of bond order in the stripe phase. We suggest that the spin Peierls order emerges in hole-rich domain walls (DWs) formed between hole-poor regions in which long-range antiferromagnetic (AF) correlations exist. On the example of a single stripe we analyze the stability of such structures. The motion of a hole inside the DW which takes the form of a bond ordered ladder is in principle unrestricted...