Development Of Third Harmonic Generation As A Short Pulse Probe Of Shock Heated Material

We are studying high-pressure laser produced shock waves in silicon (100). To examine the material dynamics, we are performing pump-probe style experiments utilizing 600 ps and 40 fs laser pulses from a Ti:sapphire laser. Two-dimensional interferometry reveals information about the shock breakout, while third harmonic light generated at the rear surface is used to infer the crystalline state of the material as a function of time. Sustained third harmonic generation (THG) during a similar to 100 kbar shock breakout indicate that the rear surface remains crystalline for at least 3 ns. However, a decrease in THG during a similar to 300 kbar shock breakout suggests a different behavior, which could include a change in crystalline structure.Mechanical Engineerin

Laser-Driven Acceleration In Clustered Plasmas

We propose a new approach to avoid dephasing limitation of laser wakefield acceleration by manipulating the group velocity of the driving pulse using clustered plasmas. We demonstrated the control of phase velocity in clustered plasmas by third harmonic generation and frequency domain interferometry experiments. The results agree with a numerical model. Based on this model, the group velocity of the driving pulse in clustered plasmas was calculated and the result shows the group velocity can approach the speed of light c in clustered plasmas.Physic

Magnetic translator bearings

A magnetic bearing system for enabling translational motion includes a carriage and a shaft for movably supporting the carriage; a first magnetic bearing fixed to one of the carriage and shaft and slidably received in a first channel of the other of the carriage and shaft. The first channel is generally U shaped with two side walls and a back wall. The magnetic bearing includes a pair of spaced magnetic pole pieces, each pole piece having a pair of electromagnetic coils mounted on poles on opposite ends of the pole piece proximate the side walls, and a third electromagnetic coil mounted on a pole of the pole piece proximate the backwall; a motion sensor for sensing translational motion along two axes and rotationally about three axes of the carriage and shaft relative to each other; and a correction circuit responsive to the sensor for generating a correction signal to drive the coils to compensate for any misalignment sensed between the carriage and the shaft

Using arts‐based methods to develop service user led learning materials for social work education

Theories transmitted to students about professional practice in health and social care come traditionally from the perspective of practitioners, often as a heroic narrative, inevitably casting the service‐user in a passive role (Wiltshire, 2006). Post‐modern theorists like Foucault (1973) call this the authoritative 'gaze' that objectifies the user of public services, generating a power relationship between the professional and the service user. New perspectives are needed to redress this imbalance, drawing on the narratives of the service‐users themselves (Greenhalgh, 2006). Since 2007, a project led by service‐users at London South Bank University has been experimenting with new approaches to developing learning and teaching materials for social work education using opportunities afforded by the recent accreditation of awards within the General Social Care Council’s new Post Qualifying Framework. This paper outlines some of our experiences to date of experimenting with creative arts‐based approaches to facilitate the development of learning materials as ‘inherently creative acts’ (Sagan, 2007). This paper documents the experiences of a small group of service users and academics as we have all worked in different ways to co‐produce it using different mediums and media in order to contribute our views

Ultrafast Radial Transport In A Micron‐Scale Aluminum Plasma Excited At Relativistic Intensity

Using femtosecond microscopy, we observe a thermal/ionization front expand radially at ∼108cm/s from a λ2‐size spot of an aluminum target excited at >1018W/cm2. Numerical modeling shows transport is predominantly radiative and may be initially nonlocal. © 2004 American Institute of PhysicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87543/2/609_1.pd

L'équipe d’aide et de sensibilisation aux opioïdes : un exemple novateur d'éducation médicale et de partenariat communautaire

Implication Statement  The Opioid Awareness and Support Team (OAST) at the Memorial University Faculty of Medicine is a novel student-led initiative designed to supplement medical student learning related to opioid use disorder and the opioids crisis. OAST has focused on grounding educational initiatives related to opioid use disorder in the local community context, working with community partners, and bringing in individuals with lived experience. We present initial findings from an Opioid Education Day that suggest student-led supplemental education for medical students can improve student knowledge surrounding opioid use.Énoncé des implications de la recherche L’équipe d’aide et de sensibilisation aux opioïdes (OAST) est une initiative des étudiants de la faculté de médecine de l’Université Memorial qui apporte un complément à la formation que reçoivent les étudiants sur le trouble lié à l’usage d’opioïdes. L'OAST s'est efforcée d’inscrire les initiatives éducatives liées à la crise des opïodes dans un contexte local en collaboration avec des partenaires communautaires et de faire participer des personnes ayant une expérience de terrain. Nous présentons les résultats préliminaires d'une journée de sensibilisation aux opioïdes qui suggèrent que cette activité éducative menée par les étudiants en médecine peut améliorer les connaissances des apprenants sur la consommation d’opioïdes

Plasma Channels And Laser Pulse Tailoring For Gev Laser-Plasma Accelerators

We have demonstrated distortion-free guiding of I TW pulses at near relativistic intensity (0.2 x 10(18) W/cm(2)) over 60 Rayleigh lengths at 20 Hz repetition rate in a preformed helium plasma channel. As steps toward efficient channeled Laser Wakefield Acceleration up to the dephasing limit, we have upgraded our laser system from I to 4 TW, adapted femtosecond interferometric diagnostics to probe plasma density fluctuations inside the channel, and developed detailed strategies for managing ionization distortions at the channel entrance and exit at the upgraded intensity. We also report simulations, and preliminary experiments, that explore a strategy for Raman-seeding laser pulses to coherently control both unchanneled and channeled LWFA in order to lower the laser energy threshold and increase the repetition rate of election pickup and acceleration.Physic