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Abstract Two alternative braced frame configurations are examined to improve the vertical distribution of seismic storey drifts and inelastic demands in multi-storey steel eccentrically braced frames (EBFs): the tied braced frame (TBF) system and a modular tied-braced frame (M-TBF) system. In TBFs, the concentration of inelastic deformation is prevented by connecting all ductile links over the frame height with vertical tie members. In the M-TBF configuration, the ties are interrupted at one or more locations along the frame height to reduce member forces while achieving the same objective as the TBF. The performance of each bracing system is investigated through nonlinear response history analysis for 8-, 16-, and 24-storey prototype building structures. For the 16-storey building, two M-TBF configurations are examined, two 8-storey modules and four 4-storey modules, to investigate the influence of this parameter. The analysis results show that the TBFs exhibited smaller and more uniform storey drifts and residual drifts at the expense of high axial force demands in the tie members. Soft-storey response could also be mitigated with M-TBFs, but member forces diminished significantly when adopting a modular tied braced frame configuration, which led to a reduction in the required steel tonnage with limited increases in peak and residual drift demands. Performance assessment using incremental dynamic analysis showed that the 16-storey EBF could not pass the FEMA P695 collapse safety criteria whereas all tied braced frames could exhibit satisfactory performance. Highlights • Seismic response of EBF enhanced with modular elastic trusses (M-TBF). • Significant reduction in member forces in M-TBFs when compared to TBFs. • M-TBFs can prevent soft-storey formation and reduce residual drifts. • IDA shows that M-TBFs have adequate collapse safety capacity. [ABSTRACT FROM AUTHOR]

Abstract A practical seismic design method is proposed for tall steel braced frames with segmental elastic trussed spines (SESBFs) used to achieve a uniform storey drift response. The method combines the forces arising from yielding of ductile elements along the braced frame height with the forces resulting from higher modes involving flexural dynamic response of the elastic truss segments. The first set of forces is obtained from static analysis whereas response spectrum analysis is used for the second one. The method is applied and validated for 8-storey and 16-storey SESBFs derived from conventional EBFs. The SESBF configurations including one, two, and four elastic truss segments were examined. The studied structures were located in Vancouver, B.C., and their behaviour was examined through nonlinear time history analysis. The proposed design method provides excellent predictions of the peak force demand imposed on the truss members. The elastic flexural response of truss segments is not bounded by yielding of the frame ductile elements and was found to be sensitive to ground motion signatures and damping assumptions. For taller frames with long truss segments, complete yielding of an individual segment as assumed in design was not observed in the analyses and the proposed method predicted conservative member forces. Highlights • A practical design method for SESBFs is developed and validated numerically • The method uses modal superposition technique and response spectrum analysis • The method can accurately predict maximum forces in structural members • SESBFs designed with the method exhibit good seismic response [ABSTRACT FROM AUTHOR]

This article presents an analytical model to predict the normal thrust force for the design of the restraining system of all-steel buckling-restrained brace (BRB) members. The proper design of the restraining mechanism is key to obtaining a stable inelastic response from BRBs. Compared with existing models, the presented model accounts for the cyclic strain hardening behaviour of the BRB's steel core, the flexibility of the restraining system, the flow of frictional forces, the longitudinal variation of the core axial load and strain, and Poisson's effects on the core cross-section properties. The buckled shape of the core and the resulting normal thrust and frictional forces are evaluated along the core length using an iterative approach to satisfy the force equilibrium and geometric compatibility. The model predicts the maximum compressive and tensile loads resisted by the brace, buckling wavelengths, and the magnitude and distribution of the normal thrust and the frictional force along the core. Using a simplified stability analysis, the required restraining stiffness to achieve a stable inelastic response and avoid excessive gap opening is provided. A method to estimate the available restraining stiffness of a typical bolted all-steel BRB is presented and the internal actions in the restraining system resulting from the local buckling of the core are obtained through a simple and practical analysis. The analytical model is validated against the results of physical tests and finite element analyses for two different BRB members. The model was found to provide sufficiently accurate results for typical earthquake engineering applications. [ABSTRACT FROM AUTHOR]

An experimental program consisting of quasi-static cyclic, pull-back and seismic shake table tests was conducted to examine the inelastic seismic response of cold-formed selective rack structures. Hysteretic response of the connectors and base plates are presented. In the seismic tests, racks could sustain up to 10% drifts without collapse. Pallet sliding was observed in the tests. A numerical model is proposed in OpenSees to predict the rack seismic response, including pallet sliding. It is used to study the response of 6-bay racks having 3–6 levels. Displacements are sensitive to assumed viscous damping, base plate properties and pallet sliding. [ABSTRACT FROM AUTHOR]

Conventional buckling restrained braces used in concentrically braced frames are expected to yield in both tension and compression without significant degradation of capacity under severe seismic ground motions. On the other hand, a new short core buckling restrained brace system could be introduced as an alternative for a conventional full core BRB. In a short core BRB (SCBRB), the core element is built shorter than usual. Therefore, for a given story drift, the core accepts bigger axial strains compared to a conventional (full core) BRB. A short core BRB seems to be easily fabricated, inspected, and replaced after a severe earthquake. The purpose of this study is to show how this type of buckling restrained braces is feasible. Reducing the core length in a buckling restrained brace may result in a shorter encasing member, decrease in frictional forces acting at the core and buckling restraining mechanism interface, and, as a consequence, reduction of the compression strength adjustment factor in the brace. This paper numerically investigates the seismic behavior of short core buckling restrained braced frames. The minimum core length of BRB is determined by considering the low cycle fatigue life of the core plate and the maximum anticipated strain demand under standard loading protocol. Nonlinear time history analyses were also performed on four and ten story prototype buildings equipped with full core (conventional BRBs) and short core BRBs and the story drifts were compared. The results showed that the SCBRB system is partially able to reduce the story and residual story drifts in the braced frames. In addition, SCBRBs sustain large plastic deformations without crossing the low cycle fatigue life borders or instability of the encasing system. However, the economic and practical aspects of using SCBRB seem to be more distinct in comparison to its mechanical characteristics. [ABSTRACT FROM AUTHOR]

Abstract: The main purpose of this paper is to introduce and investigate a new class of generalized Apostol–Bernoulli polynomials based on a definition given by Natalini and Bernardini (2003)  for the generalized Bernoulli polynomials. We obtain a generalization of the Srivastava–Pintér addition theorem (Srivastava and Pintér (2004) ). We also give a list of expressions involving special functions that could be used to obtain some analogues of the Srivastava–Pintér addition theorem. Finally, we give an analogue featuring the new class of generalized Apostol–Bernoulli polynomials. [Copyright &y& Elsevier]

Abstract: The adequacy of the 30%-rule to predict the seismic demand on bridge columns subjected to bi-directional earthquake components is examined for two North American sites in areas of moderate seismic hazard: Montreal, in the east, and Vancouver, along the west coast. For both sites, historical and simulated ground motion earthquake ensembles are considered. Time history analyses were performed on generic bridge models to determine the critical response of the columns under pairs of orthogonal seismic ground motion time histories. Response spectrum analyses were also carried out to determine the maximum response in each direction and the critical response was estimated using the 30%-rule. The results show that the combination rule is tributary of both ground motion and bridge characteristics. Results also show that the 30%-rule as currently prescribed in codes leads to an adequate estimation of the bi-directional elastic seismic demand on regular bridge columns. [Copyright &y& Elsevier]

Abstract: Arc-spot welds fabricated in multi-overlap configurations are found in roof deck construction when steel sheets are stacked at a sidelap or endlap. A welding technique that maximizes the quality of arc-spot welds fabricated through several layers of thick sheets is presented. Weld specimens were fabricated through 1, 2 or 4 layers of steel sheets with thicknesses ranging from 0.76 to 1.52 mm (22 to 16 gauge). The most important factors to control during the welding are the current (high intensity), the electrode type (E4311) and the welding technique. Various sheet steel/weld configurations found in roof deck construction were included. Adequate weld quality could be achieved in all cases except that welds were undersized when the ratio of the thickness of the underlying material to total sheet thickness was less than 0.7. A total of 72 tension tests and 107 shear tests were completed. Of those, 31 shear specimens were loaded with a reversed cyclic protocol to examine the behaviour of arc-spot welds subject to seismic loading. All other specimens were loaded under monotonically increasing displacement. The results were compared with the provisions of the CSA S136 North American Specification for the Design of Cold-Formed Steel Structural Members. The CSA S136 equations for shear and tension resistance of arc-spot welds are generally conservative, even for welds fabricated through multi-overlap configurations with total sheet steel thicknesses exceeding the 3.81 mm limit. Nonetheless, modifications to the equation for the effective diameter and to Equations E2.2.1.2-2, E2.2.2-1, and E2.2.2-2 are recommended. [Copyright &y& Elsevier]

Abstract: In 1971, T.J. Osler propose a generalization of Taylor’s series of f(z) in which the general term is , where 0< a ⩽1, b ≠ z 0 and γ is an arbitrary complex number and is the fractional derivative of order α. In this paper, we present a new expansion of an analytic function f(z) in in terms of a power series θ(t)= tq(t), where q(t) is any regular function and t is equal to the quadratic function [(z − z 1)(z − z 2)] , z 1 ≠ z 2, where z 1 and z 2 are two points in and the region of validity of this formula is also deduced. To illustrate the concept, if q(t)=1, the coefficient of (z − z 1) n (z − z 2) n in the power series of the function (z − z 1) α (z − z 2) β f(z) is where α and β are arbitrary complex numbers. Many special forms are examined and some new identities involving special functions and integrals are obtained. [Copyright &y& Elsevier]

PURPOSE: To examine whether there is a direct or a mediated association between dysfunctional parental behavior in later childhood and involvement in dating violence in a sample of low socioeconomic-status boys during mid-adolescence. METHODS: Subjects were 717 boys who participated in a longitudinal study. Data collected at six time periods, beginning at age 10 years and covering a span of 8 years, were analyzed. Dysfunctional parental behavior patterns were defined as perceived harsh parenting practices, laxness of monitoring, and interparental conflict witnessed by the subject. Perpetrated psychological and physical abuse in dating, measured at ages 16 and 17 years, and delinquency, measured at age 15 years, served as dependent measures. All instruments were self-report questionnaires. Multiple regression analysis was used in data analysis. RESULTS: Only two variables contributed independently to dating violence. Boys who perceived laxness of monitoring from their parents in their late childhood and reported antisocial behavior at age 15 years, such as delinquency and substance abuse, were at risk of becoming involved in violent dating relationships at age 16 years. Harsh parenting practices from ages 10 to 12 years were also predictors of dating violence. CONCLUSIONS: A direct relationship was found between harsh parenting and antisocial behavior and later dating violence. No support was found for the mediation hypothesis of antisocial behavior, but an indirect influence was noted in association with monitoring. [ABSTRACT FROM AUTHOR]

Abstract: The microstructure and phase composition of die cast and thixocast ZAEX10430 (Mg–10Zn–4Al–3Ce–0.3Ca) alloy were studied. Two intermetallic phases were identified in both the die cast and the thixocast specimens: the τ-phase doped with calcium (Mg,Ca)32(Al,Zn)49 (or τ′-phase) and the (Al,Zn)xCe isomorphous phase with Al2CeZn2 and Al4Ce. In all of the specimens, the τ′-phase crystallized mostly as fine elongated particles and within a lamellar constituent. Needle-like (Al,Zn)xCe phase particles were visible in the die cast specimens, whereas coarse particles of various cross-sectional shapes (polygonal, elliptical, rod-like, etc.) were observed in the thixocast specimens. The difference in morphology of the intermetallic (Al,Zn)xCe particles in the matrix and the presence of large primary α-Mg grains in the thixocast specimens was used to explain the different creep behavior of die cast and thixocast ZAEX10430 alloy reported previously. [Copyright &y& Elsevier]

Abstract: Fatigue failure affects the majority of materials in various applications and is particularly detrimental to aluminium alloys which do not present a well-defined endurance capacity. With the growing use of aluminium castings in automotive industry and several other fields, it is important to compare the fatigue strength of components produced by different moulding processes. In this study, thin-walled components of aluminium A383.0 alloy were moulded using four industrial casting processes: die casting, vacuum die casting, squeeze casting, and permanent mould casting (gravity casting). Bending fatigue strength and tensile properties of the cast components were then compared according to their surface roughness and microstructural characteristics. [Copyright &y& Elsevier]

Abstract: This paper reports on an improved method to evaluate both the strength and the permeability of ceramic shell specimens under high temperature conditions. In order to maintain safe testing conditions and use lower testing pressure, a spherical wax model, larger than the standard ping-pong ball, was used to prepare ceramic shells. Compressed air was introduced into ceramic shell specimen held at 900°C. Air flow and pressure drop across the shell wall were measured and hot permeability was calculated according to Darcy''s law. Air pressure was subsequently increased and recorded up to bursting point. A hoop stress formula was used to calculate the hot strength from the bursting pressure. This very simple method is easy to implement in foundries. [Copyright &y& Elsevier]

Abstract: The influence of the microstructure on the corrosion behavior of AXJ530 magnesium alloy has been investigated at room temperature in a 3.5% NaCl solution at pH 6 and 25 °C. Specimens of AXJ530 alloy were cut out from ingots and from billets cast in permanent mould with and without electromagnetic stirring. The corrosion behavior of the AXJ530 specimens was studied by potentiodynamic polarization, electrochemical noise analysis, and immersion tests. The phase composition, the morphology of corroded surface and its evolution with time were also analyzed. Potentiodynamic polarization studies and electrochemical noise analysis indicate that the corrosion resistance of ingot specimens is lower than the specimens cut from billets. A study of the surface of specimens after immersion tests has shown that the different corrosion behavior can be ascribed to the specific morphology, distribution and volume fraction of phases in the microstructure of specimens. [Copyright &y& Elsevier]

Abstract: In this work, AZ91D magnesium alloy was cast in solid plaster mould using vacuum assistance. The influence of process parameters and wall thickness on the microstructure and tensile properties of cast specimens was studied. Within the range of experimental parameters, it was found that casting and mould preheating temperatures have minor influence on mechanical properties. However, gating design proved to affect the microstructure and tensile properties of cast specimens. Compared to bottom filling, top filling led to casting defects that seriously impaired the mechanical properties. Generally, tensile properties increased with a decrease of section thickness, this improvement being explained by a reduction of dendrite arms spacing and grain size. Finally, the mechanical properties of solid mould investment cast specimens were compared with those obtained by foamed plaster casting, sand casting, permanent mould casting and die-casting. [Copyright &y& Elsevier]

Abstract: The stiffening effect of nonstructural roofing components on the in-plane shear stiffness of metal roof deck diaphragms was studied. Tests were performed to determine the properties of the non-structural roofing materials and the typical diaphragm connectors. A linear elastic FE model was used to establish stiffness values for common diaphragm configurations, and the results were applied to evaluate the impact of nonstructural roofing elements on the fundamental period of vibration of single-storey steel buildings. The shear stiffness increase due to the nonstructural components was found to be more pronounced for the flexible steel deck diaphragms. The influence on the period of vibration was negligible for most of the buildings studied. [Copyright &y& Elsevier]

Abstract: Manganese is currently added to Mg–Al alloys in order to improve the corrosion behavior of cast components. A part of this manganese is dissolved in the magnesium matrix and the balance is found as fine Al(Mn,Fe) particles dispersed within castings. For AZ91D specimens prepared using the plaster mould investment casting process, these particles were observed in very large quantity at the surface of castings. These particles were characterized by scanning electron microscopy and electron probe microanalysis. It was found that they consist of Al8Mn5 phase and that their morphology and size depend on local solidification conditions. Their presence at the surface of the castings is related to low solidification rates and reduced thermal gradients at the mould/metal interface. [Copyright &y& Elsevier]

Objective: To examine girls' developmental trajectories of disruptive behaviors during the elementary school years and to predict conduct disorder symptoms and diagnosis in adolescence with trajectories of these behaviors.Method: The sample was 820 girls from the province of Quebec followed over 10 years (1986-1996). A semiparametric mixture model was used to describe girls' developmental trajectories of teacher-rated disruptive behaviors between the ages of 6 and 12 years. The trajectories were used to predict conduct disorder symptoms and diagnosis when the girls were on average 15.7 years.Results: Four groups of girls following trajectories with distinct levels of disruptive behaviors were identified: a low, medium, medium-high, and high trajectory. Prediction with the trajectories indicated that girls on the medium, medium-high, and high trajectories reported a significantly higher number of conduct disorder symptoms in adolescence. However, only the girls on the medium-high and high trajectories were at significantly higher risk to meet DSM-III-R criteria for conduct disorder, compared with girls in the low group (odds ratio: 4.46). More than two thirds of the girls with conduct disorder were in the medium or higher-level trajectories.Conclusion: The results suggest that there is an early-onset type of conduct disorder in girls. [ABSTRACT FROM AUTHOR]

Abstract: The objectives were to vaccinate peri-pubertal bulls with a modified-live vaccine consisting of cytopathic BVDV strains Singer and 296 and evaluate the resulting: (a) transient shed of modified-live, cytopathic BVDV in semen; (b) risk of prolonged testicular infection; and (c) protection against subsequent testicular infection due to viral challenge. Seronegative, peri-pubertal bulls were vaccinated subcutaneously with a standard dose of vaccine (n =11) or were maintained as unvaccinated controls (n =11). Forty-nine days after vaccination, all bulls were intranasally inoculated with a noncytopathic field strain of BVDV. Semen and testicular biopsies collected after vaccination and challenge were assayed for BVDV using virus isolation, reverse transcription-nested PCR, or immunohistochemistry, and the identity of viral strains was determined by nucleotide sequencing of PCR products. Vaccination of peri-pubertal bulls with this vaccine caused a short-term, transient shed of only the type 1a strain of modified-live, cytopathic BVDV in semen for up to 10d after vaccination. The vaccine did not cause prolonged testicular infection. Vaccination with this product prevented development of prolonged testicular infections after subsequent exposure to a field strain of BVDV. [Copyright &y& Elsevier]

The primary purpose of this research was to determine associations among seropositivity for bovine leukemia virus (BLV), bovine viral diarrhea virus (BVDV), Mycobacterium avium ssp. paratuberculosis (MAP), and Neospora caninum (NC) and each of 3 outcome variables (305-d milk, fat, and protein production) in Canadian dairy cattle. Serum samples from up to 30 randomly selected cows from 342 herds on monthly milk testing were tested for antibodies against BLV (IDEXX ELISA; IDEXX Corporation, Westbrook, ME), MAP (IDEXX or Biocor ELISA; Biocor Animal Health, Inc., Omaha, NE), and NC (IDEXX or Biovet ELISA; Biovet Inc., St. Hyacinthe, Quebec, Canada). Up to 5 unvaccinated cattle over 6 mo of age were tested for virus-neutralizing antibodies to the Singer strain of type 1 BVDV. Dairy Herd Improvement records were obtained electronically for all sampled cows. Linear mixed models with herd and cow as random variables were fit, with significant restricted maximum likelihood estimates of outcome effects being obtained, while controlling for potential confounding variables. Bovine leukemia virus seropositivity was not associated with 305-d milk, 305-d fat, or 305-d protein production. Cows in BVDV-seropositive herds (at least one unvaccinated animal with a titer ≤1:64) had reductions in 305-d milk, fat, and protein of 368, 10.2, and 9.5 kg, respectively, compared with cows in BVDV-serouegative herds. Mycobacterium avium ssp. paratuberculosis seropositivity was associated with lower 305-d milk of 212 kg in 4+-lactation cows compared with MAP-seronegative 4+-lactation cows. Neospora caninum seropositivity in primiparous cows was associated with lower 305-d milk, fat, and protein of 158, 5.5, and 3.3 kg, respectively, compared with NC-seronegative primiparous cows. There were no interactions among seropositivity for any of the pathogens and their effects on any of the outcomes examined, although the low MAP seroprevalence limited this analysis. Results from this research will contribute to understanding the economic impacts of these pathogens and justify their control. [ABSTRACT FROM AUTHOR]