Modelling thermomechanical behaviour of Cr-Mo-V steel

This paper presents a mechanism-based approach for modelling the thermomechanical behaviour of a Cr-Mo-V steel. A set of unified viscoplastic constitutive equations were employed to model dislocation density, recrystallisation and grain size during deformation. The evolution of dislocation density accounts for the build-up of dislocations due to plastic strain, the static and dynamic recovery and the effect of recrystallisation. Recrystallisation occurs when a critical dislocation density is reached after an incubation time, and grain size becomes smaller after such event. Gleeble compression tests were used to obtain Stress-strain curves and evaluate the microstructural evolution at different temperature and strain rate, and the material constants for the model were determined from the experimental data. Copyright © 2010 MS&T10®

A comparative study of angle dependent magnetoresistance in [001] and [110] La2/3Sr1/3MnO3La_{2/3}Sr_{1/3}MnO_3

The angle dependent magnetoresistance study on [001] and [110] La$_{2 / 3}$Sr$_{1 / 3}$MnO$_{3}$ thin films show that the anisotropy energy of [110] films is higher when compared with a [001] oriented La$_{2 / 3}$Sr$_{1 / 3}$MnO$_{3}$ film of similar thickness. The data has been analyzed in the light of multidomain model and it is seen that this model correctly explains the observed behavior.Comment: 8pages, 2 figure

An experimental investigation of criteria for continuous variable entanglement

We generate a pair of entangled beams from the interference of two amplitude squeezed beams. The entanglement is quantified in terms of EPR-paradox [Reid88] and inseparability [Duan00] criteria, with observed results of $\Delta^{2} X_{x|y}^{+} \Delta^{2} X_{x|y}^{-} = 0.58 \pm 0.02$ and $\sqrt{\Delta^{2} X_{x \pm y}^{+} \Delta^{2} X_{x \pm y}^{-}} = 0.44 \pm 0.01$, respectively. Both results clearly beat the standard quantum limit of unity. We experimentally analyze the effect of decoherence on each criterion and demonstrate qualitative differences. We also characterize the number of required and excess photons present in the entangled beams and provide contour plots of the efficacy of quantum information protocols in terms of these variables.Comment: 4 pages, 5 figure

Chiral magneto-phonons with tunable topology in anisotropic quantum magnets

We propose a mechanism to obtain chiral phonon-like excitations from the bond-dependent magnetoelastic couplings in the absence of out-of-plane magnetization and magnetic fields. We provide a systematic way to understand the hybrid excitation by its phononic analog, and thus we dub it magneto-phonon. We recognize that the system is equivalent to the class D of topological phonons, and show the tunable chirality and topology by an in-plane magnetic field in the example of a triangular lattice ferromagnet. As a possible experimental probe, we evaluate the phonon magnetization and the thermal Hall conductivity. Our study gives a new perspective on tunable topological and chiral excitations without Dzyaloshinskii-Moriya or Raman spin interactions, which suggests possible applications of spintronics and phononics in various anisotropic magnets and/or Kitaev materials

Upper branch thermal Hall effect in quantum paramagnets

Inspired by the persistent thermal Hall effects at finite temperatures in various quantum paramagnets, we explore the origin of the thermal Hall effects from the perspective of the upper branch parts by invoking the dispersive and twisted crystal field excitations. It is shown that the upper branches of the local energy levels could hybridize and form the dispersive bands. The observation is that, upon the time-reversal symmetry breaking by the magnetic fields, these upper branch bands could acquire a Berry curvature distribution and contribute to the thermal Hall effect in the paramagnetic regime. As a proof of principle, we consider the setting on the kagom\'e lattice with one ground state singlet and an excited doublet, and show this is indeed possible. We expect this effect to be universal and has no strong connection with the underlying lattice. Although the thermal Hall signal can be contributed from other sources such as phonons and their scattering in the actual materials, we discuss the application to the Mott systems with the large local Hilbert spaces

Airline Customer Satisfaction 2015-2017 Results

Previous research on perceptions, satisfaction, and attitudes regarding the major commercial air carriers in the United States has provided little more than an interesting descriptive representation of the average air traveler. This study moves beyond basic descriptive information of air travelers to identify attitudinal patterns and relationships in the way consumers at varying levels of travel frequency view the commercial air industry. The Airline Passenger Survey (APS) elements developed via the utilization of rigorous scientific methodology, with the intention of capturing the most important data from passengers while reducing confusion or variability in comprehension of questions. APS items are a combination of demographic variables, categorical data, and Likert-type scale responses asking participants to evaluate statements regarding the current state of the airline industry

Reasoned modelling with Event-B

This paper provides an overview of how the Event-B language and verification method can be used to model and reason about system behaviour. Formal modelling and reasoning help to increase understanding and reduce defects in requirements specification. Sets and relations play a key role in modelling as do operators on these structures. Precise definitions and rules are provided in order to help the reader gain a strong understanding of the mathematical operators for sets and relations. While the emphasis is on mathematical reasoning, particularly through invariant proofs, the paper also covers less formal reasoning such as identification of problem entities supported by class diagrams and validation of formal models against informal requirements. The use of tools for animation, model checking and proof is also outlined

Spin-on-carbon hard masks utilising fullerene derivatives

Spin-on-Carbon (SoC) hardmasks are an increasingly key component of the microchip fabrication process. Progress in lithographic resolution has made the adoption of extremely thin photoresist films necessary for the fabrication of “1x nanometre” linewidth structures to prevent issues such as resist collapse during development. While there are resists with high etch durability [1], ultimately etch depth is limited by resist thickness. A possible solution is the use of a multilayer etch stack. This allows for considerable increase in aspect ratio. For the organic hard mask base layer, a carbon-rich material is preferred as carbon possesses a high etch resistance in silicon plasma etch processes. A thin silicon topcoat deposited on the carbon film can be patterned with a thin photoresist film without feature collapse, and the pattern transferred to the underlying carbon film by oxygen plasma. This produces high aspect ratio carbon structures suitable for substrate etching. In terms of manufacturability it is beneficial to spin coat the carbon layer instead of using chemical vapor deposition [2], but the presence of carbon-hydrogen bonds in typical spin-on-carbon leads to line wiggling during the etch (a significant problem at smaller feature sizes). We have previously introduced a fullerene based SoC and reported on material characterization [3,4,5]. The materials low Ohnishi number provides high etch durability and the low hydrogen level allows for high resolution etching without wiggling. The use of the materials in such etch stacks is demonstrated (figures 1-3). A 20nm thin silicon film was sputtered on top of the carbon layers. Resist patterns are defined by e-beam, and in the case of figure 2, EUV lithography and transferred to the silicon thin film using SF6/CHF3 etch chemistry. The carbon layer was then etched by O2 plasma using the silicon mask and finally the pattern was transferred into the silicon substrate using the same process used to etch the topcoat. Recent advances in material development and work towards commercialization of the materials will be reported. Some results from external evaluations of the original 100 series will be presented, together with recent developments with the newer 200 and 300 series formulations (offering improved thermal stability and etch durability). [1] J. Manyam, M. Manickam, J.A. Preece, R.E. Palmer, and A.P.G. Robinson, Proc. SPIE 7972 (2011) 79722N. [2] C.Y. Ho, X.J. Lin, H.R. Chien, C. Lien, Thin Solid Films 518 (2010) 6076 [3] A. Frommhold, J. Manyam, R.E. Palmer, and A.P.G. Robinson, Proc. SPIE 8328 (2012) 83280U [4] A. Frommhold, R.E. Palmer, and A.P.G. Robinson, J. Micro/Nanolith. MEMS MOEMS. 12 (3), 033003 (2013) [5] A Frommhold, A G. Brown, T Lada, A P. G. Robinson, Proc SPIE 9421-21 (2015

Continuous-Variable Spatial Entanglement for Bright Optical Beams

A light beam is said to be position squeezed if its position can be determined to an accuracy beyond the standard quantum limit. We identify the position and momentum observables for bright optical beams and show that position and momentum entanglement can be generated by interfering two position, or momentum, squeezed beams on a beam splitter. The position and momentum measurements of these beams can be performed using a homodyne detector with local oscillator of an appropriate transverse beam profile. We compare this form of spatial entanglement with split detection-based spatial entanglement.Comment: 7 pages, 3 figures, submitted to PR

Survey of ultrasound practice amongst podiatrists in the UK

Background: Ultrasound in podiatry practice encompasses musculoskeletal ultrasound imaging, vascular hand-held Doppler ultrasound and therapeutic ultrasound. Sonography practice is not regulated by the Health and Care Professions Council (HCPC), with no requirement to hold a formal qualification. The College of Podiatry does not currently define ultrasound training and competencies. This study aimed to determine the current use of ultrasound, training received and mentorship received and/or provided by podiatrists using ultrasound. Methods: A quantitative study utilising a cross-sectional, on-line, single-event survey was undertaken within the UK. Results: Completed surveys were received from 284 podiatrists; 173 (70%) use ultrasound as part of their general practice, 139 (49%) for musculoskeletal problems, 131 (46%) for vascular assessment and 39 (14%) to support their surgical practice. Almost a quarter (n=62) worked for more than one organisation; 202 (71%) were employed by the NHS and/or private sector (n=118, 41%). Nearly all (93%) respondents report using a hand-held vascular Doppler in their daily practice; 216 (82%) to support decisions regarding treatment options, 102 (39%) to provide diagnostic reports for other health professionals, and 34 (13%) to guide nerve blocks. Ultrasound imaging was used by 104 (37%) respondents primarily to aid clinical decision making (n=81) and guide interventions (steroid injections n=67; nerve blocks n=39). Ninety-three percent stated they use ultrasound imaging to treat their own patients, while others scan at the request of other podiatrists (n=28) or health professionals (n=18). Few use ultrasound imaging for research (n=7) or education (n=2). Only 32 (11%) respondents (n=20 private sector) use therapeutic ultrasound to treat patients presenting with musculoskeletal complaints, namely tendon pathologies. Few respondents (18%) had completed formal post-graduate CASE (Consortium for the Accreditation of Sonographic Education) accredited ultrasound courses. Forty (14%) respondents receive ultrasound mentorship; the majority from fellow podiatrists (n=17) or medical colleagues (n=15). Over half (n=127) who do not have ultrasound mentorship indicated they would like a mentor predominantly for ultrasound imaging. Fifty-five (19%) report they currently provide ultrasound mentorship for others. Conclusions: Understanding the scope of ultrasound practice, the training undertaken and the requirements for mentorship will underpin the development of competencies and recommendations defined by the College of Podiatry to support professional development and ensure safe practice.</p