Erratum: "Ab initio calculations on the ground and excited states of BeOH and MgOH" [J. Chem. Phys. 111, 10484 (1999)]

Journal URL: http://jcp.aip.org

Ab initio calculations on the ground and excited states of BeOH and MgOH

Journal URL: http://jcp.aip.org

Optimisation of the Explosive Compaction Process for Powder-In- Tube MgB 2 Superconductors Using Numerical Simulations

High quality, ex-situ powder-in-tube (PIT) Introduction Nowadays, superconductivity has a significant impact on many technological sectors, for example in the production of electric motors and magnetic sensors as well as in the energy transmission and storage technology. Superconducting wires and tapes are the key product for the adoption of this high technology, but the selection of a suitable superconducting material is not an easy task. MgB 2 is in general a low cost superconductor compared to other ceramic high T c materials, with a transition temperature near the liquid hydrogen boiling point. It has been estimated that approximately 15% of the generated electricity is dissipated during power transportation. In that respect, MgB 2 can be used for the construction of zero loss superconducting transmission lines, where liquid hydrogen may serve as refrigeration medium. The production of wires, coils and tapes requires forming at very high pressures due to the poor formability of the extremely hard ceramic superconductors. For this reason, the powder-in-tube (PIT) explosive compaction technique is considered to be a very promising powder metallurgy forming process for the fabrication of near full density MgB 2 superconductors as given in The present work is concerned with the optimization of the explosive compaction process, incorporating MgB 2 powders. The optimization is performed on an LS-DYNA numerical simulation model of the explosive compaction, where the external diameter of the tube and the dimensions (length and diameter) of the explosive surrounding of the PIT are used as input parameters. The peak pressure, peak maximum principal stress, porosity, uniformity of the tube radius, and mass of the explosive, are the corresponding simulation outputs, with the porosity being the most important parameter to optimize, since it is directly related to the interparticle bonding of the compact which affects the critical current density of the superconductor. Numerical Simulation of Explosively Densified PIT MgB Powders The shock consolidation process of the superconducting powders is numerically simulated using the LSDYNA finite element code. Since the PIT sample deformation during explosive loading is considered to be axisymmetric, a quarter 3D explicit finite element model is developed which is sufficient to accurately simulate the compaction procedure reducing this way the computational time. The finite element model mesh together with the corresponding experimental setup are demonstrated i

Kinetic and Transport Equations for Localized Excitations in Sine-Gordon Model

We analyze the kinetic behavior of localized excitations - solitons, breathers and phonons - in Sine-Gordon model. Collision integrals for all type of localized excitation collision processes are constructed, and the kinetic equations are derived. We analyze the kinetic behavior of localized excitations - solitons, breathers and phonons - in Sine-Gordon model. Collision integrals for all type of localized excitation collision processes are constructed, and the kinetic equations are derived. We prove that the entropy production in the system of localized excitations takes place only in the case of inhomogeneous distribution of these excitations in real and phase spaces. We derive transport equations for soliton and breather densities, temperatures and mean velocities i.e. show that collisions of localized excitations lead to creation of diffusion, thermoconductivity and intrinsic friction processes. The diffusion coefficients for solitons and breathers, describing the diffusion processes in real and phase spaces, are calculated. It is shown that diffusion processes in real space are much faster than the diffusion processes in phase space.Comment: 23 pages, latex, no figure

Deregulation of methylation of transcribed-ultra conserved regions in colorectal cancer and their value for detection of adenomas and adenocarcinomas

Expression of Transcribed Ultraconserved Regions (T-UCRs) is often deregulated in cancer. The present study assesses the expression and methylation of three T-UCRs (Uc160, Uc283 and Uc346) in colorectal cancer (CRC) and explores the potential of T-UCR methylation in circulating DNA for the detection of adenomas and adenocarcinomas. Expression levels of Uc160, Uc283 and Uc346 were lower in neoplastic tissues from 64 CRC patients (statistically significant for Uc160, p<0.001), compared to non-malignant tissues, while methylation levels displayed the inverse pattern (p<0.001, p=0.001 and p=0.004 respectively). In colon cancer cell lines, overexpression of Uc160 and Uc346 led to increased proliferation and migration rates. Methylation levels of Uc160 in plasma of 50 CRC, 59 adenoma patients, 40 healthy subjects and 12 patients with colon inflammation or diverticulosis predicted the presence of CRC with 35% sensitivity and 89% specificity (p=0.016), while methylation levels of the combination of all three T-UCRs resulted in 45% sensitivity and 74.3% specificity (p=0.013). In conclusion, studied T-UCRs’ expression and methylation status are deregulated in CRC while Uc160 and Uc346 appear to have a complicated role in CRC progression. Moreover their methylation status appears a promising non-invasive screening test for CRC, provided that the sensitivity of the assay is improved

Optimization and deployment of CNNs at the Edge: The ALOHA experience

Deep learning (DL) algorithms have already proved their effectiveness on a wide variety of application domains, including speech recognition, natural language processing, and image classification. To foster their pervasive adoption in applications where low latency, privacy issues and data bandwidth are paramount, the current trend is to perform inference tasks at the edge. This requires deployment of DL algorithms on low-energy and resource-constrained computing nodes, often heterogenous and parallel, that are usually more complex to program and to manage without adequate support and experience. In this paper, we present ALOHA, an integrated tool flow that tries to facilitate the design of DL applications and their porting on embedded heterogenous architectures. The proposed tool flow aims at automating different design steps and reducing development costs. ALOHA considers hardware-related variables and security, power efficiency, and adaptivity aspects during the whole development process, from pre-training hyperparameter optimization and algorithm configuration to deployment

Perturbation analysis of weakly discrete kinks

We present a perturbation theory of kink solutions of discrete Klein-Gordon chains. The unperturbed solutions correspond to the kinks of the adjoint partial differential equation. The perturbation theory is based on a reformulation of the discrete chain problem into a partial differential equation with spatially modulated mass density. The first order corrections to the kink solutions are obtained analytically and are shown to agree with exact numerical results. We discuss the problem of calculating the Peierls-Nabarro barrier.Comment: 13 pages, 6 figures, REVTE

Dietary Education Provision Within a Cardiac Rehabilitation Programme in the UK: A Pilot Study Evaluating Nutritional Intakes Alongside Physical Activity Levels

Background/aims: The primary aim of this study was to evaluate the effectiveness of two 30-minute dietary education sessions, within cardiac rehabilitation (CR), as a means to optimise nutrient and energy intakes (EI). A secondary aim was to evaluate patients’ habitual physical activity (PA) levels. Methods: Thirty patients (males: n = 24, 61.8 ± 11.2 years; females: n = 6, 66.7 ± 8.5 years) attended a six-week early outpatient CR programme in the UK and received two 30-minute dietary education sessions emphasising Mediterranean diet principles. EI and nutrient intakes were measured through completion of three-day food diaries in weeks one and six (before and after the dietary education sessions) to assess the impact of these sessions on nutrient intakes. At the same time-points, a sub-group (n = 13) of patients had their PA levels assessed via accelerometery to assess the impact of the CR programme on PA. Findings: Estimated energy requirements (EER) at week one (1988 ± 366 kcal . d -1 ) were not matched by actual EI (1785 ± 561 kcal . d -1 ) ( P = 0.047, d = -0.36). EI reduced to 1655 ± 470 kcal . d -1 at week six ( P = 0.66, d = -0.33) whereas EER increased as a function of increased activity (CR sessions). Nutrient intakes remained suboptimal, while no significant increases were observed in healthy fats and fibre, which consist core elements of a Mediterranean diet. Statistically significant increases were not observed in PA however patients decreased sedentary time by 11 ± 12% in week six compared to week one ( P = 0.009; d = -0.54). Conclusion : The present study findings suggest that two 30-minute dietary education sessions did not positively influence EI and nutrient intakes, while habitual PA levels were not significantly increased as a result of the CR programme. Future research should explore means of optimising nutrition and habitual PA within UK CR