Weld-brazing - a new joining process

A joining process designated weld brazing which combines resistance spot welding and brazing has been developed. Resistance spot welding is used to position and align the parts as well as to establish a suitable faying surface gap for brazing. Fabrication is then completed by capillary flow of the braze alloy into the joint. The process has been used successfully to fabricate Ti-6Al-4V titanium alloy joints using 3003 aluminum braze alloy. Test results obtained on single overlap and hat-stiffened structural specimens show that weld brazed joints are superior in tensile shear, stress rupture, fatigue, and buckling than joint fabricated by spotwelding or brazing. Another attractive feature of the process is that the brazed joints is hermetically sealed by the braze material

Coastal Zone Management in the Mediterranean: Legal and Economic Perspectives

This paper examines existing measures taken to protect the coastal zones of the Mediterranean Sea and assesses their success. A summary of the main pressures facing these zones is given, followed by an analysis of the legislation covering coastal zone development in ten countries: Algeria, Croatia, Egypt, France, Israel, Italy, Malta, Spain, Tunisia and Turkey. We find that not all of these states have legislation specifically covering coastal zones, but there is concern in all areas that the legislation is not working, We also look at the costs and benefits of controlling coastal development. Firstly, a literature review of valuation studies identifies a range of values placed on developed and undeveloped coastline for both users and local property owners. These values were then used in a model to evaluate policy options to control development of a stretch of coastline. The model indicates that a stricter control regime of coastal development may provide significant benefits.Coastal Zone Management, Legislation, Littoral, Mediterranean, Recreation

Hydrodynamics of Micro-swimmers in Films

One of the principal mechanisms by which surfaces and interfaces affect microbial life is by perturbing the hydrodynamic flows generated by swimming. By summing a recursive series of image systems we derive a numerically tractable approximation to the three-dimensional flow fields of a Stokeslet (point force) within a viscous film between a parallel no-slip surface and no-shear interface and, from this Green's function, we compute the flows produced by a force- and torque-free micro-swimmer. We also extend the exact solution of Liron & Mochon (1976) to the film geometry, which demonstrates that the image series gives a satisfactory approximation to the swimmer flow fields if the film is sufficiently thick compared to the swimmer size, and we derive the swimmer flows in the thin-film limit. Concentrating on the thick film case, we find that the dipole moment induces a bias towards swimmer accumulation at the no-slip wall rather than the water-air interface, but that higher-order multipole moments can oppose this. Based on the analytic predictions we propose an experimental method to find the multipole coefficient that induces circular swimming trajectories, allowing one to analytically determine the swimmer's three-dimensional position under a microscope.Comment: 35 pages, 11 figures, 5 table

Medical-Legal Partnerships to Support Continuity of Care for Immigrants Impacted by HIV: Lessons Learned from California.

The United States (US) has experienced a surge of anti-immigrant policies and rhetoric, raising concerns about the influence on health outcomes for immigrants living in the US. We conducted qualitative interviews (n = 20) with health care and social service providers, attorneys, and legal/policy experts in California to understand how agencies were maintaining access to HIV care and prevention for immigrant clients. We conducted a thematic analysis to describe the role of medical-legal partnerships (MLPs) and document best practices. Informants reported high demand for legal services. Referrals were facilitated by case managers, medical providers, and pre-existing relationships between clinics and legal agencies. Informants identified a need for additional funding and further guidance on screening for and supporting patients with legal needs. MLPs have the capacity to create sustainable, efficient, comprehensive structural changes that minimize barriers to HIV prevention and treatment and improve health outcomes among immigrant populations

Nonequilibrium Quantum Phase Transitions in the Dicke Model

We establish a set of nonequilibrium quantum phase transitions in the Dicke model by considering a monochromatic nonadiabatic modulation of the atom-field coupling. For weak driving the system exhibits a set of sidebands which allow the circumvention of the no-go theorem which otherwise forbids the occurence of superradiant phase transitions. At strong driving we show that the system exhibits a rich multistable structure and exhibits both first- and second-order nonequilibrium quantum phase transitions.Comment: 4 pages, 3 Figures, and supplementary material. This new version contains corrected typos, new references and new versions of the figures. Published by Physical Review Letter

Spin-Correlation Coefficients and Phase-Shift Analysis for p+3^3He Elastic Scattering

Angular Distributions for the target spin-dependent observables A$_{0y}$, A$_{xx}$, and A$_{yy}$ have been measured using polarized proton beams at several energies between 2 and 6 MeV and a spin-exchange optical pumping polarized $^3$He target. These measurements have been included in a global phase-shift analysis following that of George and Knutson, who reported two best-fit phase-shift solutions to the previous global p+$^3$He elastic scattering database below 12 MeV. These new measurements, along with measurements of cross-section and beam-analyzing power made over a similar energy range by Fisher \textit{et al.}, allowed a single, unique solution to be obtained. The new measurements and phase-shifts are compared with theoretical calculations using realistic nucleon-nucleon potential models.Comment: Submitted to Phys. Rev.

Uranium(III) coordination chemistry and oxidation in a flexible small-cavity macrocycle

U(III) complexes of the conformationally flexible, small-cavity macrocycle trans-calix[2]benzene[2]pyrrolide (L)2–, [U(L)X] (X = O-2,6-tBu2C6H3, N(SiMe3)2), have been synthesized from [U(L)BH4] and structurally characterized. These complexes show binding of the U(III) center in the bis(arene) pocket of the macrocycle, which flexes to accommodate the increase in the steric bulk of X, resulting in long U–X bonds to the ancillary ligands. Oxidation to the cationic U(IV) complex [U(L)X][B(C6F5)4] (X = BH4) results in ligand rearrangement to bind the smaller, harder cation in the bis(pyrrolide) pocket, in a conformation that has not been previously observed for (L)2–, with X located between the two ligand arene rings