Process Analysis and Physical Simulation of Electromagnetic Joining of Thin-Walled parts

To avoid typical problems when connecting different metallic materials as aluminum and titanium as e.g. the formation of intermetallic phases, electromagnetic welding represents an alternative technology to conventional (i.e. usually thermal) joining processes. Although feasibility and potential of this technique are already proved, the fundamental correlations of part- and process-parameters have not yet been investigated systematically. As an approach to examine these, the performance of model experiments and supplementary technological tests is suggested. The resulting connection quality is evaluated using metallographic methods

Process Investigation of Tube Expansion by Gas Detonation

The present paper deals with the expansion of tubes by direct application of gas detonation waves, i.e. the gas is both pressure medium and energy source. After an introduction to gas detonation forming, measurements of the motion process and the internal pressures are presented. Results of free expansion and of forming into a die are thoroughly studied and compared to the results of quasi-static burst tests and hydroforming. Using pure aluminum Al99.5 and a medium strength alloy AlMgSi1, expansions by 25 % and 20 % respectively are obtained. A simulation delivers details on the deformation process and specially prepared probes of high-speed tension tests give new insight into metallographic material behavior at different strain rates

Observational constraints on spatial anisotropy of G from orbital motions

A phenomenological anisotropic variation \Delta G/G of the Newtonian gravitational coupling parameter G, if real, would affect the orbital dynamics of a two-body gravitationally bound system in a specific way. We analytically work out the long-term effects that such a putative modification of the usual Newtonian inverse-square law would induce on the trajectory of a test particle orbiting a central mass. Without making any a-priori simplifying assumptions concerning the orbital configuration of the test particle, it turns out that its osculating semi-major axis a, eccentricity e, pericenter \varpi and mean anomaly M undergo long-term temporal variations, while the inclination I and the node \Omega are left unaffected. Moreover, the radial and the transverse components of the position and the velocity vectors r and v of the test particle experience non-vanishing changes per orbit, contrary to the out-of-plane ones. Then, we compute our theoretical predictions for some of the major bodies of the solar system by orienting the gradient of G(r) towards the Galactic Center and keeping it fixed over the characteristic timescales involved. By comparing our calculation to the latest observational determinations for the same bodies, we infer \Delta G/G <= 10^-17 over about 1 au. Finally, we consider also the Supermassive Black Hole hosted by the Galactic Center in Sgr A^* and the main sequence star S2 orbiting it in about 16 yr, obtaining just \Delta G/G <= 10^-2 over 1 kau.Comment: LaTex2e, 18 pages, no figures, 4 tables. Accepted by Classical and Quantum Gravity (CQG). Typo fixed. Reference update

Determination of the E2/M1 Ratio in the \gamma N \to \Delta(1232) Transition from a Simultaneous Measurement of p(\vec{\gamma},p)\pi^0 and p(\vec{\gamma},\pi^+)n

Tagged linearly polarized photons have been used at the Mainz Microtron MAMI for simultaneous measurements of the p(\vec{\gamma},p)\pi^0 and p(\vec{\gamma},\pi^+)n reaction channels to study the \gamma N \to \Delta(1232) transition. The energy dependence of the magnetic dipole M_{1+}^{3/2} and electric quadrupole E_{1+}^{3/2} amplitudes have been extracted from these data in the photon energy range from 270 to 420 MeV. The E2/M1 ratio for the \gamma N \to \Delta(1232) transition has been determined to be - (2.5+-0.1_{stat}+-0.2_{sys}) % at the resonance position delta_{33}=90^0.Comment: 25 pages Latex including 13 postscript figures submitted for publication in Phys. Rev.

Effect of COVID-19 pandemic on outcomes in intracerebral hemorrhage.

ObjectivesPatients with severe intracerebral hemorrhage (ICH) often suffer from impaired capacity and rely on surrogates for decision-making. Restrictions on visitors within healthcare facilities during the pandemic may have impacted care and disposition for patient with ICH. We investigated outcomes of ICH patients during the COVID-19 pandemic compared to a pre-pandemic period.Materials and methodsWe conducted a retrospective review of ICH patients from two sources: (1) University of Rochester Get With the Guidelines database and (2) the California State Inpatient Database (SID). Patients were divided into 2019-2020 pre-pandemic and 2020 pandemic groups. We compared mortality, discharge, and comfort care/hospice. Using single-center data, we compared 30-day readmissions and follow-up functional status.ResultsThe single-center cohort included 230 patients (n = 122 pre-pandemic, n = 108 pandemic group), and the California SID included 17,534 patients (n = 10,537 pre-pandemic, n = 6,997 pandemic group). Inpatient mortality was no different before or during the pandemic in either cohort. Length of stay was unchanged. During the pandemic, more patients were discharged to hospice in the California SID (8.4% vs. 5.9%, pConclusionsUsing a large database, we identified more ICH patients discharged to hospice during the COVID-19 pandemic and, among survivors, more patients were discharged home rather than healthcare facility discharge during the pandemic

Effect of COVID-19 pandemic on outcomes in intracerebral hemorrhage

Objectives Patients with severe intracerebral hemorrhage (ICH) often suffer from impaired capacity and rely on surrogates for decision-making. Restrictions on visitors within healthcare facilities during the pandemic may have impacted care and disposition for patient with ICH. We investigated outcomes of ICH patients during the COVID-19 pandemic compared to a pre-pandemic period. Materials and methods We conducted a retrospective review of ICH patients from two sources: (1) University of Rochester Get With the Guidelines database and (2) the California State Inpatient Database (SID). Patients were divided into 2019–2020 pre-pandemic and 2020 pandemic groups. We compared mortality, discharge, and comfort care/hospice. Using single-center data, we compared 30-day readmissions and follow-up functional status. Results The single-center cohort included 230 patients (n = 122 pre-pandemic, n = 108 pandemic group), and the California SID included 17,534 patients (n = 10,537 pre-pandemic, n = 6,997 pandemic group). Inpatient mortality was no different before or during the pandemic in either cohort. Length of stay was unchanged. During the pandemic, more patients were discharged to hospice in the California SID (8.4% vs. 5.9%, pConclusions Using a large database, we identified more ICH patients discharged to hospice during the COVID-19 pandemic and, among survivors, more patients were discharged home rather than healthcare facility discharge during the pandemic

Patient characteristics for ICH admissions in the California State Inpatient Database.

Patient characteristics for ICH admissions in the California State Inpatient Database.</p

Patient outcomes in the single-center get with the guidelines data.

Patient outcomes in the single-center get with the guidelines data.</p