Fragment isospin distributions and the phase diagram of excited nuclear systems

Fragment average isospin distributions are investigated within a microcanonical multifragmentation model in different regions of the phase diagram. The results indicate that in the liquid phase $$ versus $Z$ is monotonically increasing, in the phase coexistence region it has a rise and fall shape and in the gas phase it is constant. Deviations from this behavior may manifest at low fragment multiplicity as a consequence of mass/charge conservation. Characterization of the "free" and "bound" phases function of fragment charge reconfirms the neutron enrichment of the "free" phase with respect to the "bound" one irrespectively the localization of the multifragmentation event in the phase diagram.Comment: 23 pages, 12 figure

The design and development of a spacecraft appendage tie down mechanism

The design and evolution is described of a spacecraft Appendage Tie Down Mechanism (ATDM). Particular emphasis is paid to the mechanical aspects of using dry lubricants to increase the efficiency of acme threads and worm gearing. The ATDM consists of five major components. These are a dc torque motor, a worm gear speed reducer, the tension bolt (or T-bolt), nut capture and centering jaws and the capture nut. In addition, there are several minor components such as limit switch assemblies and an antibackdrive mechanism which couples the drive motor to the worm shaft. A development model of the ATDM in various configurations was under test for some time. In its latest version, it has successfully completed thermal vacuum testing, vibration testing, and extended life testing

Chiral and Continuum Extrapolation of Partially-Quenched Hadron Masses

Using the finite-range regularisation (FRR) of chiral effective field theory, the chiral extrapolation formula for the vector meson mass is derived for the case of partially-quenched QCD. We re-analyse the dynamical fermion QCD data for the vector meson mass from the CP-PACS collaboration. A global fit, including finite lattice spacing effects, of all 16 of their ensembles is performed. We study the FRR method together with a naive polynomial approach and find excellent agreement ~1% with the experimental value of M_rho from the former approach. These results are extended to the case of the nucleon mass.Comment: 6 pages, Contribution to Lattice2005, PoS styl

Economic Incentives Versus Command and Control: What's the Best Approach for Solving Environmental Problems?

Now, decades after the first environmental laws were passed in this country, policymakers face many choices when seeking to solve environmental problems. Will taxing polluters for their discharges be more effective than fining them for not meeting certain emissions standards? Will a regulatory agency find it less costly to enforce a ban or oversee a system of tradable permits? Which strategy will reduce a pollutant the quickest? Clearly, there are no "one-size-fits-all" answers. Many factors enter into the decision to favor either policies that lean more toward economic incentives (EI) and toward direct regulation, commonly referred to as command-and-control (CAC) policy. Underlying determinants include a country's governmental and regulatory infrastructure, along with the nature of the environmental problem itself. Even with these contextual factors to consider, we thought it would be useful to compare EI and CAC policies and their outcomes in a real-world setting. To do this, we looked at six environmental problems that the United States and at least one European country dealt with differently (see box on page 14.) For each problem, one approach was more of an EI measure, while the other relied more on CAC. For example, to reduce point-source industrial water pollution, the Netherlands implemented a system of fees for organic pollutants (EI), while the United States established a system of guidelines and permits (CAC). It turned out, in fact, that most policies had at least some elements of both approaches, but we categorized them as EI or CAC based on their dominant features. We then asked researchers who had previously studied these policies on either side of the Atlantic to update or prepare new case studies. We analyzed the 12 case studies (two for each of the six environmental problems) against a list of hypotheses frequently made for or against EI and CAC, such as which instrument is more effective or imposes less administrative burden

Reinforced metallic composites Patent

High strength reinforced metallic composites for applications over wide temperature rang

Mathematics Professional Development Workshop for Middle School Teachers: Concept Versus Memorization

This article includes professional development topics for middle school mathematics and science teachers from two week-long Urban Teacher Institutes. These Institutes were held at J. Sargeant Reynolds Community College (JSRCC) and its partner institution, Virginia Commonwealth University (VCU), during the summers of 2007 and 2008, and were supported by a grant obtained by Dr. Harriet Morrison (JSRCC). Co-author Dr. Dewey Taylor directed the 2007 workshop, and both authors served as faculty leaders in both workshops. The workshops focused on teaching in an urban environment and community mapping (understanding the details of a certain locale to make the teacher more knowledgeable about the environments of both the students and the schools). The community mapping aspect of the workshops was led by Dr. Shirley Key of the University of Memphis. They featured content teaching and applications led by VCU faculty in mathematics, physics, forensics, engineering, mathematics education, and science education. This article focuses on the mathematics professional development strand in the workshop which featured conceptual learning with graphing calculator support as an alternative to the memorization of formulas

A fundamental study of electrophilic gases for plasma quenching

Electron attachment properties of high molecular weight gases for plasma quenchin

Unified chiral analysis of the vector meson spectrum from lattice QCD

The chiral extrapolation of the vector meson mass calculated in partially-quenched lattice simulations is investigated. The leading one-loop corrections to the vector meson mass are derived for partially-quenched QCD. A large sample of lattice results from the CP-PACS Collaboration is analysed, with explicit corrections for finite lattice spacing artifacts. To incorporate the effect of the opening decay channel as the chiral limit is approached, the extrapolation is studied using a necessary phenomenological extension of chiral effective field theory. This chiral analysis also provides a quantitative estimate of the leading finite volume corrections. It is found that the discretisation, finite-volume and partial quenching effects can all be very well described in this framework, producing an extrapolated value of M_\rho in excellent agreement with experiment. This procedure is also compared with extrapolations based on polynomial forms, where the results are much less enlightening.Comment: 30 pages, 13 fig