Analytical Modelling of Jointed Precast Concrete Beam-to-Column Connections with Different Damping Systems

Jointed precast concrete systems typically have low inherent damping and are thus particularly suitable for applying supplemental damping systems. Analytical modelling is utilised to characterise jointed beam-to-column rocking connections, using a rate-dependent tri-linear compound version of the well-known Menegotto-Pinto rule. The analytical model is verified against near full-scale experimental results. The beam-column connections are constructed utilising Damage Avoidance Design (DAD) principles with unbonded post-tensioned tendons. High force-to-volume extrusion-based energy dissipaters are externally fitted to provide supplemental energy dissipation and modify joint hysteretic performance. Multiple joint configurations are analysed, with supplemental damping systems modified to investigate the effect of damping forces on joint hysteresis. Particular attention is given to the re-centring limit. Good agreement between the analytical models and experimental results is demonstrated, with discussion of possible improvements. Overall, system damping behaviour is significantly improved by adding the extrusion based damping system

Urbanization and Development in the Third World

Roughly 1.8 billion people, 42 percent of the world's population, live in urban areas today, and this total is growing by almost 3 percent per year. Even more dramatic are the growth rates in large cities in developing countries. Rates of 5-8 percent are not uncommon, and the urban growth multipliers that they indicate are truly awesome - a doubling time of 8-15 years. Scholars and policy makers are divided on the issue of rapid urbanization and urban growth in the Third World. Some see these trends as effectively speeding up national processes of socioeconomic development; others believe their impacts to be largely undesirable and argue that they should be slowed down. Yet many of the determinants and consequences of urban and rural demoeconomic patterns of change are poorly understood, and there is an urgent need for improved methods of analyzing the fundamental issues and options that they bring about. The five papers in this collection, written by current or past scholars in the Area, are a representative sample of this research. Together with three papers by other authors (not included here) they form the proceedings of a symposium on urbanization in the Third World published by the journal "Economic Development and Cultural Change"

1/f Noise in Electron Glasses

We show that 1/f noise is produced in a 3D electron glass by charge fluctuations due to electrons hopping between isolated sites and a percolating network at low temperatures. The low frequency noise spectrum goes as \omega^{-\alpha} with \alpha slightly larger than 1. This result together with the temperature dependence of \alpha and the noise amplitude are in good agreement with the recent experiments. These results hold true both with a flat, noninteracting density of states and with a density of states that includes Coulomb interactions. In the latter case, the density of states has a Coulomb gap that fills in with increasing temperature. For a large Coulomb gap width, this density of states gives a dc conductivity with a hopping exponent of approximately 0.75 which has been observed in recent experiments. For a small Coulomb gap width, the hopping exponent approximately 0.5.Comment: 8 pages, Latex, 6 encapsulated postscript figures, to be published in Phys. Rev.

On the flow-level stability of data networks without congestion control: the case of linear networks and upstream trees

In this paper, flow models of networks without congestion control are considered. Users generate data transfers according to some Poisson processes and transmit corresponding packet at a fixed rate equal to their access rate until the entire document is received at the destination; some erasure codes are used to make the transmission robust to packet losses. We study the stability of the stochastic process representing the number of active flows in two particular cases: linear networks and upstream trees. For the case of linear networks, we notably use fluid limits and an interesting phenomenon of "time scale separation" occurs. Bounds on the stability region of linear networks are given. For the case of upstream trees, underlying monotonic properties are used. Finally, the asymptotic stability of those processes is analyzed when the access rate of the users decreases to 0. An appropriate scaling is introduced and used to prove that the stability region of those networks is asymptotically maximized

Quality of life associated factors in head and neck cancer patients in a developing country using the FACT-H&N

Health-related quality of life (HRQoL) associated factors are vital considerations prior to treatment decision-making for head and neck cancer patients. The study aimed to identify potential socio-demographic and clinical prognostic value of HRQoL in head and neck cancer patients in a developing country. The Functional Assessment of Cancer Therapy-Head and Neck (FACT-H&N)-V4 in Urdu language was administered among 361 head and neck cancer patients. Data were statistically tested through multivariate analysis of variance (MANOVA) and regression modeling to identify the potentially associated factors. Treatment status, tumor stage and tumor site had the strongest negative impact on patients HRQoL, with a statistically significant decrement in FACT summary scales (effect size >0.15). Moderate associated factors of HRQoL included treatment type, marital status, employment status and age (effect size range 0.06-0.15). Weak associated factors of HRQoL with a small effect size (>0.01-0.06) included tumor size and type, gender, education level and ethnicity. This study reports 12 socio-demographic and clinical variables that have a significant impact on HRQoL of head, and neck cancer patients, and that should be considered during treatment decision-making by multidisciplinary teams and also in future HRQoL studies conducted in other developing countries. (C) 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd

Scaling in Late Stage Spinodal Decomposition with Quenched Disorder

We study the late stages of spinodal decomposition in a Ginzburg-Landau mean field model with quenched disorder. Random spatial dependence in the coupling constants is introduced to model the quenched disorder. The effect of the disorder on the scaling of the structure factor and on the domain growth is investigated in both the zero temperature limit and at finite temperature. In particular, we find that at zero temperature the domain size, $R(t)$, scales with the amplitude, $A$, of the quenched disorder as $R(t) = A^{-\beta} f(t/A^{-\gamma})$ with $\beta \simeq 1.0$ and $\gamma \simeq 3.0$ in two dimensions. We show that $\beta/\gamma = \alpha$, where $\alpha$ is the Lifshitz-Slyosov exponent. At finite temperature, this simple scaling is not observed and we suggest that the scaling also depends on temperature and $A$. We discuss these results in the context of Monte Carlo and cell dynamical models for phase separation in systems with quenched disorder, and propose that in a Monte Carlo simulation the concentration of impurities, $c$, is related to $A$ by $A \sim c^{1/d}$.Comment: RevTex manuscript 5 pages and 5 figures (obtained upon request via email [email protected]

Stochastic B\"acklund transformations

How does one introduce randomness into a classical dynamical system in order to produce something which is related to the `corresponding' quantum system? We consider this question from a probabilistic point of view, in the context of some integrable Hamiltonian systems

Optimizing tuning masses for helicopter rotor blade vibration reduction including computed airloads and comparison with test data

The development and validation of an optimization procedure to systematically place tuning masses along a rotor blade span to minimize vibratory loads are described. The masses and their corresponding locations are the design variables that are manipulated to reduce the harmonics of hub shear for a four-bladed rotor system without adding a large mass penalty. The procedure incorporates a comprehensive helicopter analysis to calculate the airloads. Predicting changes in airloads due to changes in design variables is an important feature of this research. The procedure was applied to a one-sixth, Mach-scaled rotor blade model to place three masses and then again to place six masses. In both cases the added mass was able to achieve significant reductions in the hub shear. In addition, the procedure was applied to place a single mass of fixed value on a blade model to reduce the hub shear for three flight conditions. The analytical results were compared to experimental data from a wind tunnel test performed in the Langley Transonic Dynamics Tunnel. The correlation of the mass location was good and the trend of the mass location with respect to flight speed was predicted fairly well. However, it was noted that the analysis was not entirely successful at predicting the absolute magnitudes of the fixed system loads

The effect of dietary supplementation with n-3 polyunsaturated fatty acids on the synthesis of interleukin-1 and tumor necrosis factor by mononuclear cells

Contains fulltext : 4487.pdf (publisher's version ) (Open Access

Early stage scaling in phase ordering kinetics

A global analysis of the scaling behaviour of a system with a scalar order parameter quenched to zero temperature is obtained by numerical simulation of the Ginzburg-Landau equation with conserved and non conserved order parameter. A rich structure emerges, characterized by early and asymptotic scaling regimes, separated by a crossover. The interplay among different dynamical behaviours is investigated by varying the parameters of the quench and can be interpreted as due to the competition of different dynamical fixed points.Comment: 21 pages, latex, 7 figures available upon request from [email protected]