Pulsed radiolysis of model aromatic polymers and epoxy based matrix materials

Models of primary processes leading to deactivation of energy deposited by a pulse of high energy electrons were derived for epoxy matrix materials and polyl-vinyl naphthalene. The basic conclusion is that recombination of initially formed charged states is complete within 1 nanosecond, and subsequent degradation chemistry is controlled by the reactivity of these excited states. Excited states in both systems form complexes with ground state molecules. These excimers or exciplexes have their characteristics emissive and absorptive properties and may decay to form separated pairs of ground state molecules, cross over to the triplet manifold or emit fluorescence. ESR studies and chemical analyses subsequent to pulse radiolysis were performed in order to estimate bond cleavage probabilities and net reaction rates. The energy deactivation models which were proposed to interpret these data have led to the development of radiation stabilization criteria for these systems

The Thermal Environment of the Fiber Glass Dome for the New Solar Telescope at Big Bear Solar Observatory

The New Solar Telescope (NST) is a 1.6-meter off-axis Gregory-type telescope with an equatorial mount and an open optical support structure. To mitigate the temperature fluctuations along the exposed optical path, the effects of local/dome-related seeing have to be minimized. To accomplish this, NST will be housed in a 5/8-sphere fiberglass dome that is outfitted with 14 active vents evenly spaced around its perimeter. The 14 vents house louvers that open and close independently of one another to regulate and direct the passage of air through the dome. In January 2006, 16 thermal probes were installed throughout the dome and the temperature distribution was measured. The measurements confirmed the existence of a strong thermal gradient on the order of 5 degree Celsius inside the dome. In December 2006, a second set of temperature measurements were made using different louver configurations. In this study, we present the results of these measurements along with their integration into the thermal control system (ThCS) and the overall telescope control system (TCS).Comment: 12 pages, 11 figures, submitted to SPIE Optics+Photonics, San Diego, U.S.A., 26-30 August 2007, Conference: Solar Physics and Space Weather Instrumentation II, Proceedings of SPIE Volume 6689, Paper #2

Prostate cancer radiotherapy: potential applications of metal nanoparticles for imaging and therapy

Prostate cancer (CaP) is the most commonly diagnosed cancer in males. There have been dramatic technical advances in radiotherapy delivery, enabling higher doses of radiotherapy to primary cancer, involved lymph nodes and oligometastases with acceptable normal tissue toxicity. Despite this, many patients relapse following primary radical therapy, and novel treatment approaches are required. Metal nanoparticles are agents that promise to improve diagnostic imaging and image-guided radiotherapy and to selectively enhance radiotherapy effectiveness in CaP. We summarize current radiotherapy treatment approaches for CaP and consider pre-clinical and clinical evidence for metal nanoparticles in this condition

The influence of structural defects on intra-granular critical currents of bulk MgB2

Bulk MgB2 samples were prepared under different synthesis conditions and analyzed by scanning and transmission electron microscopy. The critical current densities were determined from the magnetization versus magnetic field curves of bulk and powder-dispersed-in-epoxy samples. Results show that through a slow cooling process, the oxygen dissolved in bulk MgB2 at high synthesis temperatures can segregate and form nanometer-sized coherent precipitates of Mg(B,O)2 in the MgB2 matrix. Magnetization measurements indicate that these precipitates act as effective flux pinning centers and therefore significantly improve the intra-grain critical current density and its field dependence.Comment: 4 pages, 4 figures, to be published in IEE Transactions in Applied Superconductivit

Validity of the activPAL3 activity monitor in people moderately affected by Multiple Sclerosis

Background: Walking is the primary form of physical activity performed by people with Multiple Sclerosis (MS), therefore it is important to ensure the validity of tools employed to measure walking activity. The aim of this study was to assess the criterion validity of the activPAL3 activity monitor during overground walking in people with MS.\ud Methods: Validity of the activPAL3 accelerometer was compared to video observation in 20 people moderately affected by MS. Participants walked 20-30m twice along a straight quiet corridor at a comfortable speed.\ud Results: Inter-rater reliability of video observations was excellent (all intraclass correlations > 0.99). The mean difference (activPAL3- mean of raters) was -4.70 ± 9.09, -4.55 s ± 10.76 and 1.11 s ± 1.11 for steps taken, walking duration and upright duration respectively. These differences represented 8.7, 10.0 and 1.8% of the mean for each measure respectively. The activPAL3 tended to underestimate steps taken and walking duration in those who walked at cadences of ≤ 38 steps/minute by 60% and 47% respectively.\ud Discussion: The activPAL3 is valid for measuring walking activity in people moderately affected by MS. It is accurate for upright duration regardless of cadence. In participants with slow walking cadences, outcomes of steps taken and walking duration should be interpreted with caution

An evaluation of an educational intervention (physical assessment module), for the non medical work force to provide unscheduled services across the primary and secondary sector in one SHA

The purpose of this research was to establish how an educational intervention (the physical assessment module) enabled practitioners, drawn from the non medical workforce, to meet the modernising agenda of new ways of working, notably, to provide unscheduled care and to contribute to the transformation of chronic care provision in the acute care sector and Community.To gauge the impact of the physical assessment module on the evolution of competencies to fulfil the demands of new roles in practice a responsive evaluation model was used. Data were gathered from face to face interviews, analysis of relevant documents, and direct observation of working practises. Importantly the approach sought to report findings back into the communities from which these data have arisen to verify the findings but also to enrich and update issues in a rapidly changing context. Therefore, feedback via stakeholder conferences was a critical element in the process.Data were analysed using the constant comparative method. Data analysis ran concurrently with data collection and as emergent issues arose they were abstracted and the topics explored in subsequent interviews.Key findings are presented in three tiers: from theory to practice (learning physical assessment skills and techniques and applying these in practice; from policy to practice (tracking the way in which policy was transmitted from the central government through to organisations and how this impacted on the context in which the practitioners were required to use their skills; and finally from policy to users of the service (examining the evaluation of patients and their relatives about the services provided by nurses undertaking advanced physical assessment skills

Angular dependent vortex pinning mechanisms in YBCO coated conductors and thin films

We present a comparative study of the angular dependent critical current density in YBa2Cu3O7 films deposited on IBAD MgO and on single crystal MgO and SrTiO3 substrates. We identify three angular regimes where pinning is dominated by different types of correlated and uncorrelated defects. We show that those regimes are present in all cases, indicating that the pinning mechanisms are the same, but their extension and characteristics are sample dependent, reflecting the quantitative differences in texture and defect density. In particular, the more defective nature of the films on IBAD turns into an advantage as it results in stronger vortex pinning, demonstrating that the critical current density of the films on single crystals is not an upper limit for the performance of the IBAD coated conductors.Comment: 14 pages, 3 figures. Submitted to AP

Working group written presentation: Trapped radiation effects

The results of the Trapped Radiation Effects Panel for the Space Environmental Effects on Materials Workshop are presented. The needs of the space community for new data regarding effects of the space environment on materials, including electronics are listed. A series of questions asked of each of the panels at the workshop are addressed. Areas of research which should be pursued to satisfy the requirements for better knowledge of the environment and better understanding of the effects of the energetic charged particle environment on new materials and advanced electronics technology are suggested