Windborne debris in the urban environment

This paper presents a comprehensive review of the research into using Windborne debris. It Introduces the components of the typical debris risk model - wind field model, debris generation model, debris trajectory model and debris impact model - and reviews the research That has been done in each of These constituent areas. The majority of this research has focussed on understanding the fundamental physics of debris flight, using both experimental and computational approaches to derive analytical and empirical models. This fundamental physics must be viewed, however, within a probabilistic framework That allows the risk to be Assessed in a relevant | manner. Much of the research Relates to hurricane hazard in the US, however Clearly Windborne debris is a threat to the urban environment duringEuropean wind storms. The Way That FEMA's HAZUS ®MH hazard assessment tool has brought natural hazard modeling into the engineering context is viewed as an approach that could accommodate be adapted for both mitigation and design in a European context

Redox supercapacitor performance of nanocrystalline molybdenum nitrides obtained by ammonolysis of chloride- and amide-derived precursors

Reactions of MoCl5 or Mo(NMe2)4 with ammonia result in cubic ?-Mo2N or hexagonal ?1-MoN depending on reaction time and temperature. At moderate temperatures the cubic product from Mo(NMe2)4 exhibits lattice distortions. Fairly high surface areas are observed in the porous particles of the chloride-derived materials and high capacitances of up to 275 F g?1 are observed when electrodes made from them are cycled in aqueous H2SO4 or K2SO4 electrolytes. The cyclic voltammograms suggest charge is largely stored in the electrochemical double layer at the surface of these materials. Amide-derived molybdenum nitrides have relatively low surface areas and smaller capacitances, but do exhibit strong redox features in their cyclic voltammograms, suggesting that redox capacitance is responsible for a significant proportion of the charge stored

On the applicability of 2D URANS and SST k-ω turbulence model to the fluid-structure interaction of rectangular cylinders

In this work the practical applicability of a 2D URANS approach adopting a block structured mesh and Menter's SST k-ω turbulence model in fluid-structure interaction (FSI) problems is studied using as a test case a ratio B/H = 4 rectangular cylinder. The vortex-induced vibration (VIV) and torsional flutter phenomena are analyzed based on the computation of the out-of-phase and in-phase components of the forced frequency component of lift and moment coefficients when the section is forced to periodically oscillate both in heave and pitch degrees of freedom. Also the flutter derivatives are evaluated numerically from the same forced oscillation simulations. A good general agreement has been found with both experimental and numerical data reported in the literature. This highlights the benefits of this relatively simple and straightforward approach. These methods, once their feasibility has been checked, are ready to use in parametric design of bridge deck sections and, at a later stage, in the shape optimization of deck girders considering aeroelastic constraints

Critical realism: a philosophical framework for the study of gender and mental health

This paper explores gender and mental health with particular reference to the emerging philosophical field of critical realism. This philosophy suggests a shared ontology and epistemology for the natural and social sciences. Until recently, most of the debate surrounding gender and mental health has been guided either implicitly or explicitly within a positivist or constructivist philosophy. With this in mind, key areas of critical realism are explored in relation to gender and mental health, and contrasted with the positions of positivism and constructivism. It is argued that critical realism offers an alternative philosophical framework for the exploration of gender issues within mental health care

My Way or the Highway: a More Naturalistic Model of Altruism Tested in an Iterative Prisoners' Dilemma

There are three prominent solutions to the Darwinian problem of altruism, kin selection, reciprocal altruism, and trait group selection. Only one, reciprocal altruism, most commonly implemented in game theory as a TIT FOR TAT strategy, is not based on the principle of conditional association. On the contrary, TIT FOR TAT implements conditional altruism in the context of unconditionally determined associates. Simulations based on Axelrod\'s famous tournament have led many to conclude that conditional altruism among unconditional partners lies at the core of much human and animal social behavior. But the results that have been used to support this conclusion are largely artifacts of the structure of the Axelrod tournament, which explicitly disallowed conditional association as a strategy. In this study, we modify the rules of the tournament to permit competition between conditional associates and conditional altruists. We provide evidence that when unconditional altruism is paired with conditional association, a strategy we called MOTH, it can out compete TIT FOR TAT under a wide range of conditions.Game Theory; Altruism; Prisoners' Dilemma; TIT FOR TAT; MOTH; Docking; Netlogo

Modeling the re-anchoring of a ruptured tendon in bonded post-tensioned concrete

: In this study, a theoretical model is deve loped to simulate the re-anchorage of a ruptured bonded post-tensioning tendon. This includes estimating the re-anchorage length and stress distribution over the tendon. The model accounts for equilibrium and compatibility conditions at the steel-grout, grout-duct and duct-concrete interfaces as well as the effect of axial stresses in the strand and its confining materials, i.e. grout, duct and concrete. Formulation of the model is based on the elastic theory of thick-wall cylinders and the Coulomb friction model. The model has been validated against an axi-symmetrical Finite Element (FE) model, the UK Highway Agency’s BA51/95 model and previous experimental data. The models had been compared with the UK Highway Agency’s BA51/95 model and previous experimental data

Re-anchorage of a ruptured tendon in bonded post-tensioned concrete beams: model validation

Many post-tensioned concrete bridges have been reported to have ruptured tendons due to corrosion [1] and the assessment of their residual structural capacity has to account for the possibility of re-anchorage of failed tendons. This paper presents an experimental programme to validate a numerical model developed by the authors for the re-anchorage of a ruptured tendon in post-tensioned concrete [2]. The experimental programme considered 33 post-tensioned concrete prisms, in which the rupture of tendon was simulated by releasing the tendon at one end. The full field displacement at concrete surface after release was measured using 3D Electronic Speckle Pattern Interferometry (ESPI). A wide range of parameters: tendon diameter, duct material, grout strength, concrete strength and shear reinforcement were investigated to validate the proposed model, which is found to be suitable for use in assessing post-tensioned concrete bridges with damaged tendons

Kinetics and Mechanism of Methane, Methanol, and Dimethyl Ether C−H Activation with Electrophilic Platinum Complexes

The relative rates of C−H activation of methane, methanol, and dimethyl ether by [(N-N)PtMe(TFE-d_3)]+ ((N-N) = ArN═C(Me)−C(Me)═NAr; Ar = 3,5-di-tert-butylphenyl, TFE-d_3 = CF_3CD_2OD) (2(TFE)) were determined. Methane activation kinetics were conducted by reacting 2(TFE)-^(13)C with 300−1000 psi of methane in single-crystal sapphire NMR tubes; clean second-order behavior was obtained (k = 1.6 ± 0.4 × 10^(-3) M^(-1) s^(-1) at 330 K; k = 2.7 ± 0.2 × 10^(-4) M^(-1) s^(-1) at 313 K). Addition of methanol to solutions of 2(TFE) rapidly establishes equilibrium between methanol (2(MeOD)) and trifluoroethanol (2(TFE)) adducts, with methanol binding preferentially (K_(eq) = 0.0042 ± 0.0006). C−H activation gives [(N-N)Pt(CH_2OD)(MeOD)]^+ (4), which is unstable and reacts with [(RO)B(C_6F_5)_3]^- to generate a pentafluorophenyl platinum complex. Analysis of kinetics data for reaction of 2 with methanol yields k = 2.0 ± 0.2 × 10^(-3) M^(-1) s^(-1) at 330 K, with a small kinetic isotope effect (k_H/k_D = 1.4 ± 0.1). Reaction of dimethyl ether with 2(TFE) proceeds similarly (K_(eq) = 0.023 ± 0.002, 313 K; k = 5.5 ± 0.5 × 10^(-4) M^(-1) s^(-1), k_H/k_D = 1.5 ± 0.1); the product obtained is a novel bis(alkylidene)-bridged platinum dimer, [(diimine)Pt(μ-CH_2)(μ-(CH(OCH_3))Pt(diimine)]^(2+) (5). Displacement of TFE by a C−H bond appears to be the rate-determining step for all three substrates; comparison of the second-order rate constants (k(_(methane))/k(_(methanol)) = 1/1.3, 330 K; k(_(methane))/k(_(dimethyl ether)) = 1/2.0, 313 K) shows that this step is relatively unselective for the C−H bonds of methane, methanol, or dimethyl ether. This low selectivity agrees with previous estimates for oxidations with aqueous tetrachloroplatinate(II)/hexachloroplatinate(IV), suggesting a similar rate-determining step for those reactions

Modeling the re-anchoring of a ruptured tendon in bonded post-tensioned concrete

: In this study, a theoretical model is deve loped to simulate the re-anchorage of a ruptured bonded post-tensioning tendon. This includes estimating the re-anchorage length and stress distribution over the tendon. The model accounts for equilibrium and compatibility conditions at the steel-grout, grout-duct and duct-concrete interfaces as well as the effect of axial stresses in the strand and its confining materials, i.e. grout, duct and concrete. Formulation of the model is based on the elastic theory of thick-wall cylinders and the Coulomb friction model. The model has been validated against an axi-symmetrical Finite Element (FE) model, the UK Highway Agency’s BA51/95 model and previous experimental data. The models had been compared with the UK Highway Agency’s BA51/95 model and previous experimental data