Modelling rail track deterioration and maintenance: current practices and future needs

As commercialisation and privatisation of railway systems reach the political agendas in a number of countries, including Australia, the separation of infrastructure from operating business dictates that track costs need to be shared on an equitable basis. There is also a world-wide trend towards increased pressures on rail track infrastructure through increases in axle loads and train speeds. Such productivity and customer service driven pressures inevitably lead to reductions in the life of track components and increases in track maintenance costs. This paper provides a state-of-the-art review of track degradation modeling, as well as an overview of track maintenance decision support systems currently in use in North America and Europe. The essential elements of a maintenance optimisation model currently under development are also highlighted

Rail Track Maintenance Planning: An Assessment Model

In Australia, railway track maintenance costs comprise between 25-35 percent of total freight train operating costs. Track maintenance planning models have been shown to reduce maintenance costs by 5 to 10 percent though improved planning. This paper describes a model which has been developed to deal with the track maintenance planning function at the medium to long-term levels. This model simulates the impacts of degrading railway track conditions and related maintenance work, in contrast to tradition models that mainly use expert systems. The model simulates the degrading track condition using an existing track degradation model. Track condition data from that model is used to determine if safety related speed restrictions are needed and what immediate maintenance work may be required for safe train operations. The model outputs the net present value of the benefits of undertaking a given maintenance strategy, when compared with a base-case scenario. The model approach has advantages over current models in investigating what if scenarios. The track engineer can assess the possible benefits in reduced operating costs from upgrading track infrastructure or from the use of improved maintenance equipment. After describing the model inputs and the assumptions used, the paper deals with the simulation of track maintenance and of train operating costs over time. The results of applying the model to a test track section using a number of different maintenance strategies are also given

Global poverty and inequality : a review of the evidence

Drawing on a compilation of data from household surveys representing 130 countries, many over a period of 25 years, this paper reviews the evidence on levels and recent trends in global poverty and income inequality. It documents the negative correlations between both poverty and inequality indices, on the one hand, and mean income per capita on the other. It points to the dominant role of Asia in accounting for the bulk of the world's poverty reduction since 1981. The evolution of global inequality in the last decades is also described, with special emphasis on the different trends of inequality within and between countries. The statistical relationships between growth, inequality and poverty are discussed, as is the correlation between inequality and the growth elasticity of poverty reduction. Some of the recent literature on the drivers of distributional change in developing countries is also reviewed.Inequality,Achieving Shared Growth,Services&Transfers to Poor,Population Policies,Poverty Impact Evaluation

Patient Observers and Non-perturbative Infrared Dynamics in Inflation

We have previously derived the effect of soft graviton modes on the quantum state of de Sitter using spontaneously broken asymptotic symmetries. In the present paper we reinterpret this effect in terms of particle production and relate the quantum states with and without soft modes by means of Bogoliubov transformations. This also enables us to address the much discussed issues regarding the observability of infrared effects in de Sitter from a new perspective. While it is commonly agreed that infrared effects are not visible to a single sub-horizon observer at late times, we argue that the question is less trivial for a {\it patient observer} who has lived long enough to have a record of the state before the soft mode was created. Though classically there is no obstruction to measuring this effect locally, we give several indications that quantum mechanical uncertainties may censor the effect. We then apply our methods to find a non-perturbative description of the quantum state pertaining to the Page time of de Sitter, and derive with these new methods the probability distribution for the local quantum states of de Sitter and slow-roll inflation in the presence of long modes. Finally, we use this to formulate a precise criterion for the existence of eternal inflation in general classes of slow-roll inflation.Comment: 37 page

Protecting the poor from macroeconomic shocks

Many developing countries faced macroeconomic shocks in the 1980s and 1990s. The impact of the shocks on welfare depended on the nature of the shock, on initial household and community conditions, and on policy responses. To avoid severe and lasting losses to poor and vulnerable groups, governments and civil society need to be prepared for a flexible response well ahead of the crisis. A key component of a flexibly responsive system is an effective permanent safety net, which will typically combine a work-fare program with targeted transfers and credit. Once a crisis has happened, several things should be done: 1) Macroeconomic policies should aim to achieve stabilization goals at the least cost to the poor. Typically, a temporary reduction in aggregate demand is inevitable but as soon as a sustainable external balance has been reached and inflationary pressures have been contained, macroeconomic policy should be eased (interest rates reduced and efficient public spending restored, to help offset the worst effects of the recession on the poor). A fiscal stimulus directed at labor-intensiveactivities (such as building rural roads) can combine the benefits of growth with those of income support for poor groups, for example. 2) Key areas of public spending should be protected, especially investments in health care, education, rural infrastructure, urban sanitation, and micro-finance. 3) Efforts should be made to preserve the social fabric and build social capital. 4) Sound information should be generated on the welfare impacts of the crisis.Labor Policies,Public Health Promotion,Economic Theory&Research,Environmental Economics&Policies,Health Economics&Finance,Health Economics&Finance,Health Monitoring&Evaluation,Environmental Economics&Policies,Poverty Assessment,Economic Theory&Research

On the future of controllable fluid film bearings

This work gives an overview of the theoretical and experimental achievements of mechatronics applied to fluid film bearings. Compressible and uncompressible fluids are addressed. Rigid and elastic (deformable) bearing profiles are investigated. Hydraulic, pneumatic, magnetic and piezoelectric actuators are used. The ideas of combining control techniques, informatics with hydrodynamic, thermo-hydrodynamic, elasto-hydrodynamic and thermo-elasto-hydrodynamic lubrication techniques are carefully explored in this paper, considering theoretical as well as experimental aspects. The main goal of using controllable fluid film bearings is to improve the overall machine performance by: controlling the lateral vibration of rigid and flexible rotating shafts; modifying bearing dynamic characteristics, such as stiffness and damping properties; increasing the rotational speed ranges by enhancing damping and eliminating instability problems, for example, by compensating cross-coupling destabilizing effects; reducing start-up torque and energy dissipation in bearings; compensating thermal effects. It is shown that such controllable fluid film bearings can act as “smart” machine components and be applied to rotating and reciprocating machines with the goal of avoiding unexpected stops of plants, performing rotor dynamic tests and identifying model parameters “on site”. Emphasis is given to the controllable lubrication (hybrid and active) applied to different types of oil film bearings under different lubrication regimes, i.e., as tilting-pad journal bearings, multi-recess journal bearings and plain journal bearings. After a comprehensive overview of the theoretical and experimental technological advancements achieved in university laboratories, the feasibility of industrial applications is highlighted, trying to foresee the future trends of such mechatronic devices

Integral Inequalities and their Applications to the Calculus of Variations on Time Scales

We discuss the use of inequalities to obtain the solution of certain variational problems on time scales.Comment: To appear in Mathematical Inequalities & Applications (http://mia.ele-math.com). Accepted: 14.01.201