Tensor virial equation of evolving surfaces in sintering of aggregates of particles by diffusion

The moment of inertia tensor is a quantity that characterizes the morphology of aggregates of particles. The deviatoric components indicate the anisotropy of the aggregate, and its compactness is described by the isotropic component, i.e. the second moment of inertia, which is related to the radius of gyration. The equation of motion of the moment of inertia tensor is proposed for the sintering and coalescence of crystalline particles by bulk diffusion and surface diffusion. Simulations of the evolution of aggregates of particles (linear chains, rings and branched chains) show that the aggregates become more compact and more isotropic structures, driven by the surface energy tensor or the surface force density. The tensor virial equation for diffusion is applicable also to evolution of pores, precipitates and inclusions embedded in a surrounding matrix

Magnetocardiography with a modular spin-exchange relaxation free atomic magnetometer array

We present a portable four-channel atomic magnetometer array operating in the spin exchange relaxation-free regime. The magnetometer array has several design features intended to maximize its suitability for biomagnetic measurement, specifically foetal magnetocardiography, such as a compact modular design, and fibre coupled lasers. The modular design allows the independent positioning and orientation of each magnetometer, in principle allowing for non-planar array geometries. Using this array in a magnetically shielded room, we acquire adult magnetocadiograms. These measurements were taken with a 6-11 fT Hz^(-1/2) single-channel baseline sensitivity that is consistent with the independently measured noise level of the magnetically shielded room.Comment: 15 pages, 5 figure

Mannitol for acute traumatic brain injury.

BACKGROUND: Mannitol is sometimes dramatically effective in reversing acute brain swelling, but its effectiveness in the on-going management of severe head injury remains open to question. There is evidence that, in prolonged dosage, mannitol may pass from the blood into the brain, where it might cause reverse osmotic shifts that increase intracranial pressure. OBJECTIVES: To assess the effects of different mannitol therapy regimens, of mannitol compared to other intracranial pressure (ICP) lowering agents, and to quantify the effectiveness of mannitol administration given at other stages following acute traumatic brain injury. SEARCH STRATEGY: The review drew on the search strategy for the Injuries Group as a whole. We checked reference lists of trials and review articles, and contacted authors of trials. SELECTION CRITERIA: Randomised trials of mannitol, in patients with acute traumatic brain injury of any severity. The comparison group could be placebo-controlled, no drug, different dose, or different drug. Trials where the intervention was started more than eight weeks after injury, and cross-over trials were excluded. DATA COLLECTION AND ANALYSIS: The reviewers independently rated quality of allocation concealment and extracted the data. Relative risks (RR) and 95% confidence intervals (CI) were calculated for each trial on an intention to treat basis. MAIN RESULTS: Overall there were few eligible trials. In the pre-operative management of patients with acute intracranial haemorrhage the administration of high-dose mannitol resulted in reduced mortality (RR=0.55; 95%CI 0.36, 0.84) and reduced death and severe disability (RR=0.58; 95%CI 0.45, 0.74) when compared with conventional-dose mannitol. One trial compared ICP-directed therapy to 'standard care' (RR for death= 0.83; 95%CI 0.47,1.46). One trial compared mannitol to pentobarbital (RR for death = 0.85; 95% CI 0.52, 1.38). No trials compared mannitol to other ICP-lowering agents. One trial tested the effectiveness of pre-hospital administration of mannitol against placebo (RR for death=1.75; 95% CI 0.48, 6.38). REVIEWER'S CONCLUSIONS: High-dose mannitol appears to be preferable to conventional-dose mannitol in the pre-operative management of patients with acute intracranial haematomas. However, there is little evidence about the use of mannitol as a continuous infusion in patients with raised intracranial pressure in patients who do not have an operable intracranial haematoma. Mannitol therapy for raised ICP may have a beneficial effect on mortality when compared to pentobarbital treatment. ICP-directed treatment shows a small beneficial effect compared to treatment directed by neurological signs and physiological indicators. There are insufficient data on the effectiveness of pre-hospital administration of mannitol to preclude either a harmful or a beneficial effect on mortality

Microstructure and mechanical effects of spark plasma sintering in alumina monolithic ceramics

The specific effects of spark plasma sintering (SPS) on the creep behavior, microstructure and mechanical properties of alumina monolithic ceramic were investigated. SPS introduces strains that concentrate at grain boundaries and inhibit crack growth, resulting in an improvement in the flexural strength and fracture toughness. However, creep blocks grain boundary movements and decreases the reliability of the material. These strains can be removed by a post-sintering thermal treatment, which plays an important role in the distribution of dislocations. Crown Copyright (c) 2012 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. All rights reserved.The authors would like to acknowledge the help of the EU for the financial support received under the IP-NANOKER NMP3-CT-2005-515784. A.B. acknowledges the Spanish Ministry of Science and Innovation for her Juan de la Cierva Contract (JCI-2011-10498). The authors are grateful to the Central Support Service in Experimental Research (SCSIE), University of Valencia for providing the HR-TEM facility.Alvarez-Clemares, I.; Borrell Tomás, MA.; Agouram, S.; Torrecillas, R.; Fernandez, A. (2013). Microstructure and mechanical effects of spark plasma sintering in alumina monolithic ceramics. Scripta Materialia. 68(8):603-606. https://doi.org/10.1016/j.scriptamat.2012.12.016S60360668

Fabrication of Mullite Body Using Superplastic Transient Phase

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65799/1/j.1151-2916.1992.tb05542.x.pd

Effect of a liquid Phase on Superplasticity of 2-moI%-Y 2 0 3 -StabiIlzed Tetragonal Zirconla Polycrystals

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66013/1/j.1151-2916.1990.tb09806.x.pd

Capturing data for emergency department performance monitoring purposes.

Background: Good-quality data is required for valid and reliable key performance indicators. Little is known of the facilitators and barriers of capturing the required data for emergency department key performance indicators. This study aimed to explore and understand how current emergency department data collection systems relevant to emergency department key performance indicators are integrated into routine service delivery, and to identify the resources required to capture these data elements. Methods: Following pilot testing, we conducted two focus groups with a multi-disciplinary panel of 14 emergency department stakeholders drawn from urban and rural emergency departments, respectively. Focus groups were analyzed using Attride-Stirling's framework for thematic network analysis. Results: The global theme "Understanding facilitators and barriers for emergency department data collection systems" emerged from three organizing themes: "understanding current emergency department data collection systems"; "achieving the ideal emergency department data capture system for the implementation of emergency department key performance indicators"; and "emergency department data capture systems for performance monitoring purposes within the wider context". Conclusion: The pathways to improving emergency department data capture systems for emergency department key performance indicators include upgrading emergency department information systems and investment in hardware technology and data managers. Educating stakeholders outside the emergency department regarding the importance of emergency department key performance indicators as hospital-wide performance indicators underpins the successful implementation of valid and reliable emergency department key performance indicators