World Bank treatment of the social impact of adjustment programs

Since 1987 the Bank's operational guidelines have required President's Reports supporting structural adjustment loans (SALs) to pay particular attention to an analysis of the short term impact of the adjustment program on the poor and to measures proposed to alleviate negative effects. The authors review how SAL President's Reports prepared between July 1986 and December 1988 have addressed the social impact issue. The authors find that most efforts to address this issue have focused on targeted projects, including special employment programs, nutrition projects, resettlement projects, and credit, severance pay, and retraining projects for displaced workers. By contrast, there has been little analysis of the impact of the chosen policy mix on major sub-groups in poverty. Design modifications other than reallocations of social expenditures, have received relatively less attention. For example, the composition, incidence, and effectiveness of public expenditures and their implications for reducing poverty have not generally been examined. In preparing for adjustment operations, Bank staff should explore policy choices that eliminate economic distortions in a way that creates a basis for a more equitable pattern of long-term growth. To the extent that some adjustment measures may hurt the poor in the short term, this should be mitigated through appropriate modifications in SAL design and carefully designed targeted projects.Environmental Economics&Policies,Poverty Assessment,Health Economics&Finance,Health Monitoring&Evaluation,ICT Policy and Strategies

Finite volume approach for the instationary Cosserat rod model describing the spinning of viscous jets

The spinning of slender viscous jets can be described asymptotically by one-dimensional models that consist of systems of partial and ordinary differential equations. Whereas the well-established string models possess only solutions for certain choices of parameters and set-ups, the more sophisticated rod model that can be considered as $\epsilon$-regularized string is generally applicable. But containing the slenderness ratio $\epsilon$ explicitely in the equations complicates the numerical treatment. In this paper we present the first instationary simulations of a rod in a rotational spinning process for arbitrary parameter ranges with free and fixed jet end, for which the hitherto investigations longed. So we close an existing gap in literature. The numerics is based on a finite volume approach with mixed central, up- and down-winded differences, the time integration is performed by stiff accurate Radau methods

Water-accelerated organic transformations

Rather than quenching all reactive intermediates and arresting the reaction, the addition of catalytic or stoichiometric (1-10 equiv.) quantities of H2O to organic and organometallic processes can lead to surprisingly beneficial effects on reaction rate, product yield, and regio-, diastereo- and enantioselectivity. A most intriguing aspect of H2O-promoted transformations is the role that this strong Lewis-base can play in providing a source for more highly Lewis-acidic species. This scenario is most likely operative when H2O is added to reaction mixtures containing alanes, but organozinc reagents or organocuprates also seem to be transformed accordingly. In addition, the oxide or hydroxide ligand on the metal presents a source for chelation interactions that change aggregation states of organometallics and can provide anchimeric assistance. In many cases, water has been found to be an effective hydrolyzing agent leading to secondary products that serve as catalysts or promoters. In some cases, it has been shown that water provides a quenching agent capable of driving chemical equilibria towards the desired products

Barbur Boulevard: Designing a Model Civic Corridor for the 21st Century

94 pagesThe transit infrastructure along Barbur Boulevard in southwest Portland creates significant safety hazards due to intermittent bicycle lanes and sidewalks. The need for improved pedestrian, bicyclist, and motorist safety, as well as increased housing and public transportation options in the Southwest Corridor (SWC) of Portland have spurred an assement of the potential for transit-oriented development along Barbur Boulevard. TriMet has asked students in the Landscape Architecture 4/594 Fall Planning Studio to analyze and experimentally design a 2.5-mile segment of Barbur Boulevard to accommodate a center-running light rail line. This project aims to reduce automobile congestion; improve safety for all modes of transportation; increase connectivity between neighborhoods adjacent to Barbur Boulevard and downtown Portland; promote a diversity of employment opportunities, mixed income housing, and urban amenities; and integrate stormwater facilities, trees, and public green spaces into the streetscape. The 2.5-mile segment of Barbur Boulevard was divided into seven distinct study areas. Threeperson design teams were responsible for conducting in-depth analyses of their study area and producing plans for three standard right-of-way cross sections identified by TriMet with potential for the final street design. Each team was responsible for analyzing current conditions within their site across six broad categories: property viability and future development; urban spatial patterns and boundaries; natural capital and systems; land use; off-arterial vehicular circulation; and pedestrian and bicycle safety and circulation. Each of these six categories required multiple analyses and methodological approaches. Analysis maps were used extensively to inform street design and planning decisions throughout the studio. In addition, each team created projections for building footprints and massing, land use classifications, and potential timeframe for redevelopment to accompany their finalized street design plans

Stability of Liquid Rope Coiling

International audienceA thin ‘rope' of viscous fluid falling from a sufficient height coils as it approaches a rigid surface. Here we perform a linear stability analysis of steady coiling, with particular attention to the ‘inertiogravitational' regime in which multiple states with different frequencies exist at a fixed fall height. The basic states analyzed are numerical solutions of asymptotic ‘thin-rope' equations that describe steady coiling. To analyze their stability, we first derive in detail a set of more general equations for the arbitrary time-dependent motion of a thin viscous rope. Linearization of these equations about the steady coiling solutions yields a boundary-eigenvalue problem of order twenty-one which we solve numerically to determine the complex growth rate. The multivalued portion of the curve of steady coiling frequency vs. height comprises alternating stable and unstable segments whose distribution agrees closely with high-resolution laboratory experiments. The dominant balance of (perturbation) forces in the instability is between gravity and the viscous resistance to bending of the rope; inertia is not essential, although it significantly influences the growth rate

Model for coiling and meandering instability of viscous threads

A numerical model is presented to describe both the transient and steady-state dynamics of viscous threads falling onto a plane. The steady-state coiling frequency w is calculated as a function of fall height H. In the case of weak gravity, w ~ H^{-1} and w ~ H are obtained for lower and higher fall heights respectively. When the effect of gravity is significant, the relation w ~ H^2 is observed. These results agree with the scaling laws previously predicted. The critical Reynolds number for coil-uncoil transition is discussed. When the gravity is weak, the transition occurs with hysteresis effects. If the plane moves horizontally at a constant speed, a variety of meandering oscillation modes can be observed experimentally. The present model also can describe this phenomenon. The numerically obtained state diagram for the meandering modes qualitatively agrees with the experiment.Comment: 12 pages, 10 figure

A discrete geometric approach for simulating the dynamics of thin viscous threads

We present a numerical model for the dynamics of thin viscous threads based on a discrete, Lagrangian formulation of the smooth equations. The model makes use of a condensed set of coordinates, called the centerline/spin representation: the kinematical constraints linking the centerline's tangent to the orientation of the material frame is used to eliminate two out of three degrees of freedom associated with rotations. Based on a description of twist inspired from discrete differential geometry and from variational principles, we build a full-fledged discrete viscous thread model, which includes in particular a discrete representation of the internal viscous stress. Consistency of the discrete model with the classical, smooth equations is established formally in the limit of a vanishing discretization length. The discrete models lends itself naturally to numerical implementation. Our numerical method is validated against reference solutions for steady coiling. The method makes it possible to simulate the unsteady behavior of thin viscous jets in a robust and efficient way, including the combined effects of inertia, stretching, bending, twisting, large rotations and surface tension

Small-scale convection in a plume-fed low-viscosity layer beneath a moving plate

Two-dimensional simulations using a thermomechanical model based on a finite-difference method on a staggered grid and a marker in cell method are performed to study the plume-lithosphere interaction beneath moving plates. The plate and the convective mantle are modelled as a homogeneous peridotite with a Newtonian temperature- and pressure-dependent viscosity. A constant velocity, ranging from 5 to 12.5 cm yr−1, is imposed at the top of the plate. Plumes are generated by imposing a thermal anomaly of 150 to 350 K on a 50 km wide domain at the base of the model (700 km depth); the plate atop this thermal anomaly is 40 Myr old. We analyse (1) the kinematics of the plume as it impacts the moving plate, (2) the dynamics of time-dependent small-scale convection (SSC) instabilities developing in the low-viscosity layer formed by spreading of hot plume material at the base of the lithosphere and (3) the resulting thermal rejuvenation of the lithosphere. The spreading of the plume material at the base of the lithosphere, characterized by the ratio between the maximum down- and upstream horizontal (dimensionless) velocities in the plume-fed sublithospheric layer, Peup/Pedown depends on the ratio between the maximum plume upwelling velocity and the plate velocity, Peplume/Peplate. For fast plate velocities and sluggish plumes (low Peplume/Peplate), plate motion drags most plume material and downstream flow is dominant. As Peplume/Peplate increases, an increasing part of the plume material flows upstream. SSC systematically develops in the plume-fed sublithospheric layer, downstream from the plume. Onset time of SSC decreases with the Rayleigh number. For vigorous plumes, it does not depend on plate velocity. For more sluggish plumes, however, variations in the plume spreading behaviour at the base of the lithosphere result in a decrease in the onset time of SSCs with increasing plate velocity. In any case, SSC results in uplift of the isotherm 1573 K by up to 20 km relative to its initial equilibrium depth at the impact poin