1,249 research outputs found

    Three-Dimensional Microfabrication With Conjugated Polymers

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    In this paper we reported the microfabrication of three-dimensional structures using two-photon polymerization (2PP) in a mixture of MEH-PPV and an acrylic resin. Femtosecond laser operating at 800nm was employed for the two-photon polymerization processes. As a first step in this project we obtained the better composition in order to fabricate microstructers of MEH-PPV in the resin via two-photon polymerzation. Acknowledgement:This research is support by Mazur Group, Harvrad Universirt

    Comparison of Predicted and Experimental Behaviour of RC Slabs Subjected to Blast using SDOF Analysis

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    Explosions emanating from terrorist attacks or military weapons cause damage to civilian and military facilities. Understanding the mechanical behaviour of reinforced concrete structures subjected to blast is of paramount importance for minimizing the possible blast damage. A full-scale experimental program consisting of six reinforced concrete slabs with compressive strengths of 60 MPa, 50 MPa and 40 MPa, measuring 1.0 m × 1.0 m × 0.08 m, and subjected to 2.7 kg of non-confined plastic bonded explosive, was conducted in blast test area of Science and Technology Aerospace Department (Brazilian Air Force). This paper compares experimentally measured peak displacement values with theoretical values. Theoretical analysis was carried out using single degree of freedom (SDOF) models. The comparison showed that SDOF analysis worked very well in predicting the reinforced concrete slab peak displacement against blast effects. Qualitative analysis after the experiments showed that the blast wave shape generated by the cylindrical explosive was not uniformly distributed on the slabs for the standoff distance of 0.927 m∕kg1/3

    Quality of Life of People Living with HIV in Australia: The Role of Stigma, Social Disconnection and Mental Health.

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    HIV is a manageable chronic illness, due to advances in biomedical management. However, many people living with HIV (PLHIV) continue to experience psychosocial challenges, which have been associated with poorer quality of life (QoL). This study aimed to explore how psychosocial factors contributed to the QoL of PLHIV in Australia; specifically, the relationship between HIV-related stigma, social connectedness, mental health, and QoL. Participants were 122 PLHIV attending The Albion Centre (a tertiary HIV clinic in Sydney, Australia), who completed questionnaires which measured HIV-related stigma, social support, mental health symptomology and QoL. Results indicated that HIV-related stigma predicted poorer QoL, as did mental health symptomology. Conversely, social connectedness improved QoL. Additionally, social connectedness was found to mediate the relationship between HIV-related stigma and QoL, whereas the hypothesized moderating role of mental health symptomology on this model was not significant. These findings provide insight into the impact of psychosocial factors on QoL, offering practitioners various points of clinical intervention

    High Pressure And High Magnetic Field Studies Of The Electronic Transport Properties Of The Antiferromagnet Eu3ir4sn13

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    In this work we report the effects of hydrostatic pressure and magnetic field on the electronic transport properties of the antiferromagnetic compound Eu(3)Ir(4)Sni(3) (T-N similar to 10 K). Single crystals of Eu3Ir4Sn13 were synthesized using the Sn self-flux technique. DC electrical resistivity measurements as a function of temperature were performed by means of the four-probe technique. The high-temperature anomaly at T* similar to 57 K attributed to a structural distortion of the Sn1Sn2(12) cages in Eu3Ir4Sn13 is rapidly decreased to lower temperatures at a rate dT*/dP = 2 K/kbar, while the antiferromagnetic transition due to the Eu2+ ions is only weakly affected. Our data do not indicate any magnetoelastic effect associated with the structural instability at T*. Furthermore, the suppression of the lattice distortion by application of external pressure is not accompanied by the emergence of superconductivity, possibly due to strong magnetic correlations between the Eu2+ localized magnetic moments.59

    Feasibility of a Self-Paced Educational Intervention Protocol on Standardized Assessment of Public Building Accessibility

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    Limited research informs the implementation of web-based and mobile learning (mLearning) protocols for the assessment of public building accessibility in occupational therapy graduate students. This study tested the feasibility of a self-paced protocol designed to teach students how to evaluate community environment accessibility. Students across five sites completed an online learning module and community building evaluations. Students were randomized into lecture or lab educational groups and then crossed over to receive the second experience. Outcomes were student satisfaction, self-perceived learning, and knowledge on a researcher-developed measure. Data were analyzed using descriptive statistics. Two hundred and twelve students completed the study. The students were satisfied with their education and their community accessibility knowledge significantly increased from approximately 60% to 85%. Site and order of the learning components did not impact student ability to achieve competence. This multi-site approach is feasible and effective in instructing students in this highly protocolized and specialized area of practice

    Cosmic ray short burst observed with the Global Muon Detector Network (GMDN) on June 22, 2015

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    We analyze the short cosmic ray intensity increase ("cosmic ray burst": CRB) on June 22, 2015 utilizing a global network of muon detectors and derive the global anisotropy of cosmic ray intensity and the density (i.e. the omnidirectional intensity) with 10-minute time resolution. We find that the CRB was caused by a local density maximum and an enhanced anisotropy of cosmic rays both of which appeared in association with Earth's crossing of the heliospheric current sheet (HCS). This enhanced anisotropy was normal to the HCS and consistent with a diamagnetic drift arising from the spatial gradient of cosmic ray density, which indicates that cosmic rays were drifting along the HCS from the north of Earth. We also find a significant anisotropy along the HCS, lasting a few hours after the HCS crossing, indicating that cosmic rays penetrated into the inner heliosphere along the HCS. Based on the latest geomagnetic field model, we quantitatively evaluate the reduction of the geomagnetic cut-off rigidity and the variation of the asymptotic viewing direction of cosmic rays due to a major geomagnetic storm which occurred during the CRB and conclude that the CRB is not caused by the geomagnetic storm, but by a rapid change in the cosmic ray anisotropy and density outside the magnetosphere.Comment: accepted for the publication in the Astrophysical Journa

    Towards understanding the variability in biospheric CO2 fluxes:Using FTIR spectrometry and a chemical transport model to investigate the sources and sinks of carbonyl sulfide and its link to CO2

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    Understanding carbon dioxide (CO2) biospheric processes is of great importance because the terrestrial exchange drives the seasonal and interannual variability of CO2 in the atmosphere. Atmospheric inversions based on CO2 concentration measurements alone can only determine net biosphere fluxes, but not differentiate between photosynthesis (uptake) and respiration (production). Carbonyl sulfide (OCS) could provide an important additional constraint: it is also taken up by plants during photosynthesis but not emitted during respiration, and therefore is a potential means to differentiate between these processes. Solar absorption Fourier Transform InfraRed (FTIR) spectrometry allows for the retrievals of the atmospheric concentrations of both CO2 and OCS from measured solar absorption spectra. Here, we investigate co-located and quasi-simultaneous FTIR measurements of OCS and CO2 performed at five selected sites located in the Northern Hemisphere. These measurements are compared to simulations of OCS and CO2 using a chemical transport model (GEOS-Chem). The coupled biospheric fluxes of OCS and CO2 from the simple biosphere model (SiB) are used in the study. The CO2 simulation with SiB fluxes agrees with the measurements well, while the OCS simulation reproduced a weaker drawdown than FTIR measurements at selected sites, and a smaller latitudinal gradient in the Northern Hemisphere during growing season when comparing with HIPPO (HIAPER Pole-to-Pole Observations) data spanning both hemispheres. An offset in the timing of the seasonal cycle minimum between SiB simulation and measurements is also seen. Using OCS as a photosynthesis proxy can help to understand how the biospheric processes are reproduced in models and to further understand the carbon cycle in the real world

    Nonlinear electrodynamics and the Pioneer 10/11 spacecraft anomaly

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    The occurrence of the phenomenon known as photon acceleration is a natural prediction of nonlinear electrodynamics (NLED). This would appear as an anomalous frequency shift in any modeling of the electromagnetic field that only takes into account the classical Maxwell theory. Thus, it is tempting to address the unresolved anomalous, steady; but time-dependent, blueshift of the Pioneer 10/11 spacecrafts within the framework of NLED. Here we show that astrophysical data on the strength of the magnetic field in both the Galaxy and the local (super)cluster of galaxies support the view on the major Pioneer anomaly as a consequence of the phenomenon of photon acceleration. If confirmed, through further observations or lab experiments, the reality of this phenomenon should prompt to take it into account in any forthcoming research on both cosmological evolution and origin and dynamical effects of primordial magnetic fields, whose seeds are estimated to be very weak.Comment: Final version accepted for publication in Europhysics Letters, uses EPL style, 7 page

    Effects of Electron Beam Irradiation and Antimicrobials on the Volatiles, Color and Texture of Ready-to-Eat Turkey Breast Roll

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    Adding 2% SL increased the hardness, springiness, cohesiveness, chewiness, and resilience of breast rolls. The color a* and b*values of turkey rolls with 2% SL added were significantly lower than those of the control, and this difference was maintained after irradiation and during storage. Breast rolls containing antimicrobials had more lipid oxidation than control. Irradiation promoted the formation of dimethyl disulfide and dimethyl trisulfide. Adding PB in breast rolls greatly increased the formation of benzene during irradiation. It also implies that certain spices or foods containing high amounts of phenolic compounds may not be suitable for irradiation. The combination of SL and SDA has a strong potential as an antimicrobial treatment for RTE meats, but low-dose irradiation (\u3c2.0 kGy) is preferred due to side effects of irradiation
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