Belleville spring assembly with elastic guides

Belleville spring assembly with elastic guides having low hysteresi

ALPS generant tank and cell assembly

Diaphragm and balloon bladders for hydrazine expulsion in liquid propellant system and titanium tank fabricatio

HARM: A Numerical Scheme for General Relativistic Magnetohydrodynamics

We describe a conservative, shock-capturing scheme for evolving the equations of general relativistic magnetohydrodynamics. The fluxes are calculated using the Harten, Lax, and van Leer scheme. A variant of constrained transport, proposed earlier by T\'oth, is used to maintain a divergence free magnetic field. Only the covariant form of the metric in a coordinate basis is required to specify the geometry. We describe code performance on a full suite of test problems in both special and general relativity. On smooth flows we show that it converges at second order. We conclude by showing some results from the evolution of a magnetized torus near a rotating black hole.Comment: 38 pages, 18 figures, submitted to Ap

Ibn al-balad vs. Ibn al-zawat in the land of the two pharaohs

© 2016 The Institute, Inc. An analysis of Egypt’s January 2011 uprising reveals a strong class, and classist, dimension: a deep and pervasive antagonism between the upper and lower classes, between the classes that are westernized elites and those that are from the popular sectors of the population. These two segments are identified as ibn al-balad “sons of the country” and ibn al-zawat “people of importance” (“awlad” is the plural of “ibn”). The essay contends that the Islamist elements in the political arena, Muslim Brothers, Salafis, and liberal Islamists, represent the lower classes whereas the secular liberal parties are a reflection of elite interests. The essay focuses on the “sons of the country.” After describing the government’s massacre of Islamists in August 2013, it traces how government policy in the 1960s forced large numbers of villagers to migrate from the countryside and replenish the ranks of the urban working classes. The policies discussed here are (1) the government’s extensive agricultural price controls that engineered poverty, and (2) the regulation of the construction sector and its countless small informal sector firms that employ these migrants. The paternalism that permeates the agricultural and construction sectors is the same paternalism that binds working-class supporters (awlad al-balad) to middle-class professionals in the latter’s campaign to mount an Islamist program of radical political reform. The government attacked the Islamists and their populist program in 1992 in the “Battle of Imbaba” and again in the massacre at Rab\u27a al-Adawiya mosque in August 2013. It was this reform program that catapulted Muhammad Mursi and the Muslim Brotherhood’s Freedom and Justice Party into office through two elections, and it was this reform program that antagonized the awlad al-zawat into deposing Mursi through a military coup d’état. The Islamists were declared illegal under Husni Mubarak, the first of the two pharaohs, and have been declared illegal once again under ‘Abd al-Fattah al-Sisi, the current pharaoh in power

The Twist of the Draped Interstellar Magnetic Field Ahead of the Heliopause: A Magnetic Reconnection Driven Rotational Discontinuity

Based on the difference between the orientation of the interstellar $B_{ISM}$ and the solar magnetic fields, there was an expectation that the magnetic field direction would rotate dramatically across the heliopause (HP). However, the Voyager 1 spacecraft measured very little rotation across the HP. Previously we showed that the $B_{ISM}$ twists as it approaches the HP and acquires a strong T component (East-West). Here we establish that reconnection in the eastern flank of the heliosphere is responsible for the twist. On the eastern flank the solar magnetic field has twisted into the positive N direction and reconnects with the Southward pointing component of the $B_{ISM}$. Reconnection drives a rotational discontinuity (RD) that twists the $B_{ISM}$ into the -T direction and propagates upstream in the interstellar medium towards the nose. The consequence is that the N component of $B_{ISM}$ is reduced in a finite width band upstream of the HP. Voyager 1 currently measures angles ($\delta=sin^{-1}(B_{N}/B)$) close to solar values. We present MHD simulations to support this scenario, suppressing reconnection in the nose region while allowing it in the flanks, consistent with recent ideas about reconnection suppression from diamagnetic drifts. The jump in plasma $\beta$ (the plasma to magnetic pressure) across the nose of HP is much greater than in the flanks because the heliosheath $\beta$ is greater there than in the flanks. Large-scale reconnection is therefore suppressed in the nose but not at the flanks. Simulation data suggest that $B_{ISM}$ will return to its pristine value $10-15~AU$ past the HP.Comment: 19 pages, 5 figures, submitte

Experimental Testbeds for ECOSEL: A Market Framework for Private Provision of Forest Ecosystem Services

We attempt to design a market framework (which we call ECOSEL) for private provision of forest ecosystem services. ECOSEL is a non-regulatory framework that uses a voluntary public good provision mechanism (in a form of an auction) in conjunction with a multiobjective optimization algorithm to create a market for forest ecosystem services. It is expected to be attractive to the demand side of the ecosystem service market since only Pareto-efficient bundles of services are offered for auction, and it is expected to be attractive to the supply side as well by creating a source of non-timber income for forest landowners. ECOSEL is capable of flexible response to demand for other relevant dimensions of forest-related environmental amenities such as biodiversity, viewshed or recreational services. Following Roth’s (2002) advice on behavior of economists as “market engineers”, we use both experimental economics to improve the design of the ecosystem services market. Concurrently, we provide experimental evidence on the efficiency and revenue-generating properties of a multi-good subscription game of incomplete information.Environmental Economics and Policy, Marketing,

Health policy under the microscope: a micro policy design perspective

The comparative study of health policy has focused mainly on the macrostructural dimensions of health systems and reforms that have sought to change these organizational arrangements. Thus, a great deal of attention has been paid to the multiple models of insurance against sickness risks and various modes of organizing and financing healthcare providers. However, little attention has been paid to policy tools and policy design in the health policy domain. This research gap largely impedes a focus on the micro (granular) dimension of health policy, although this is the level at which health policies impact reality and thus deliver progress toward the expected goals. Such a focus on the micro dimension could not only allow a finer-grained comparison of how health systems work but also shed light on how capable health policies are of achieving the expected outcomes. This paper fills this gap by presenting an analytical framework capable of illuminating the granular dimension of policy design (the instrumental delivery package) and shows the analytical relevance of the framework by applying it to the designs of maximum waiting time guarantee and vaccination mandate policies

Diffusion-controlled anisotropic growth of stable and metastable crystal polymorphs in the phase-field crystal model

The official published version of the article can be accessed from the link below - Copyright @ 2009 APSWe use a simple density functional approach on a diffusional time scale, to address freezing to the body-centered cubic (bcc), hexagonal close-packed (hcp), and face-centered cubic (fcc) structures. We observe faceted equilibrium shapes and diffusion-controlled layerwise crystal growth consistent with two-dimensional nucleation. The predicted growth anisotropies are discussed in relation with results from experiment and atomistic simulations. We also demonstrate that varying the lattice constant of a simple cubic substrate, one can tune the epitaxially growing body-centered tetragonal structure between bcc and fcc, and observe a Mullins-Sekerka-Asaro-Tiller-Grinfeld-type instability.This work has been supported by the EU FP7 Collaborative Project ENSEMBLE under Grant Agreement NMP4-SL-2008-213669, the Hungarian Academy of Sciences under contract OTKA-K-62588, the Academy of Finland via its COMP CoE grant, and by Tekes via its MASIT33 project. A. J. acknowledges financial support from the Finnish Academy of Science and Letters. T. P. acknowledges support from the Bolyai Ja´nos Grant