Assessment of the worthwhileness of efficient driving in railway systems with high-receptivity power supplies

Eco-driving is one of the most important strategies for significantly reducing the energy consumption of railways with low investments. It consists of designing a way of driving a train to fulfil a target running time, consuming the minimum amount of energy. Most eco-driving energy savings come from the substitution of some braking periods with coasting periods. Nowadays, modern trains can use regenerative braking to recover the kinetic energy during deceleration phases. Therefore, if the receptivity of the railway system to regenerate energy is high, a question arises: is it worth designing eco-driving speed profiles? This paper assesses the energy benefits that eco-driving can provide in different scenarios to answer this question. Eco-driving is obtained by means of a multi-objective particle swarm optimization algorithm, combined with a detailed train simulator, to obtain realistic results. Eco-driving speed profiles are compared with a standard driving that performs the same running time. Real data from Spanish high-speed lines have been used to analyze the results in two case studies. Stretches fed by 1 × 25 kV and 2 × 25 kV AC power supply systems have been considered, as they present high receptivity to regenerate energy. Furthermore, the variations of the two most important factors that affect the regenerative energy usage have been studied: train motors efficiency ratio and catenary resistance. Results indicate that the greater the catenary resistance, the more advantageous eco-driving is. Similarly, the lower the motor efficiency, the greater the energy savings provided by efficient driving. Despite the differences observed in energy savings, the main conclusion is that eco-driving always provides significant energy savings, even in the case of the most receptive power supply network. Therefore, this paper has demonstrated that efforts in improving regenerated energy usage must not neglect the role of eco-driving in railway efficiency

Implementation of environmental recovery training response to biological incidents in a human health degree

Agents involved in biological incidents and outbreaks of infection can spread easily, so response teams are required to quickly implement a recovery plan to decontaminate and restore the environment impacted by these incidents to minimise public risks. A group of academics at De Montfort University (DMU, UK), with support from first responders during the 2014-16 Ebola outbreak, are developing appropriate training to provide basic skills so human health science students can respond to biological incidents. Following the competences identified by the European Commission, we have created key competences for these students based on the core skills that any medical first responder to biological emergencies should have. To provide students with the key competences related to environmental planning, we have created specific training that consisted of a 2 hours practical plus theory related to emerging diseases and the international response provided to tackle the Ebola pandemic. The practical component was a research-led workshop to develop a complete protection and recovery plan to respond to an outbreak of infection by Cyclospora cayetanensis in an urban area. Students used the novel methodology developed by Public Health England [“UK Recovery Handbook for Biological Incidents” (Pottage et al., 2015)] [1] to select appropriate options or techniques to protect and recover the affected environment, according to the physiological characteristics of the biological agent/microorganism involved and the environment impacted. Critical thinking and discussion is also needed to select recovery options (R.O.), e.g. use of chlorine-based decontamination liquids as part of the R.O. “reactive liquids” will have limited efficacy as oocysts of Cyclospora are resistant to these. After successful testing of the training with postgraduate students, we introduced it in a level 6 module in the DMU degree programme BMedSci in Medical Science in 2016/17 (n=24). A small proportion of these BMedSci students reported that they did not enjoy (13.4%) or were not satisfied (20%) with the training provided, which could be attributed to the fact that the topic of the training (environmental sciences) was not of direct interest for these students who are studying a degree more related to medicine. However, despite the short duration of the training, students were able to tailor an appropriate response with the resources and information provided (physiological characteristics and a literature review on decontamination/inactivation techniques for Cyclospora was provided to overcome time constraints). Specifically, 73.3% indicated that they gained some public health prevention/preparedness knowledge against a biological incident; 80% highlighted that they learnt how to establish some public health interventions; and 60% learnt how to tailor a recovery plan. A few students (20%) had difficulties with the recovery concepts and the interpretation of the physiological characteristics, which may be attributed to limited background knowledge of microbiology and parasitology (as the BMedSci programme does not have a complete module dedicated to the study of these topics). In conclusion, the increased prevalence of biological contamination incidents necessitates development of appropriate training to include environmental decontamination strategies to protect human health. The short teaching intervention described in this paper could be used to easily address this necessity

Effects of percentage of blockage and flameholder downstream counterbores on lean combustion limits of premixed, prevaporized propane-air mixture

Lean combustion limits were determined for a premixed prevaporized propane air mixture with flat plate flame stabilizers. Experiments were conducted in a constant area flame tube combustor utilizing flameholders of varying percentages of blockage and downstream counterbores. Combustor inlet air velocity at ambient conditions was varied from 4 to 9 meters per second. Flameholders with a center hole and four half holes surrounding it were tested with 63, 73, and 85 percent blockage and counterbore diameters of 112 and 125 percent of the thru hole diameter, in addition to the no counterbore configuration. Improved stability was obtained by using counterbore flameholders and higher percentages of blockage. Increases in mixture velocity caused the equivalence ratio at blowout to increase in all cases

Pairing Correlations in Finite Systems: From the weak to the strong fluctuations regime

The Particle Number Projected Generator Coordinate Method is formulated for the pairing Hamiltonian in a detailed way in the projection after variation and the variation after projection methods. The dependence of the wave functions on the generator coordinate is analyzed performing numerical applications for the most relevant collective coordinates. The calculations reproduce the exact solution in the weak, crossover and strong pairing regimes. The physical insight of the Ansatz and its numerical simplicity make this theory an excellent tool to study pairing correlations in complex situations and/or involved Hamiltonians.Comment: Submitted to EPJ

Upper Energy Limit of Heavy Baryon Chiral Perturbation Theory in Neutral Pion Photoproduction

With the availability of the new neutral pion photoproduction from the proton data from the A2 and CB-TAPS Collaborations at Mainz it is mandatory to revisit Heavy Baryon Chiral Perturbation Theory (HBChPT) and address the extraction of the partial waves as well as other issues such as the value of the low-energy constants, the energy range where the calculation provides a good agreement with the data and the impact of unitarity. We find that, within the current experimental status, HBChPT with the fitted LECs gives a good agreement with the existing neutral pion photoproduction data up to $\sim$170 MeV and that imposing unitarity does not improve this picture. Above this energy the data call for further improvement in the theory such as the explicit inclusion of the \Delta (1232). We also find that data and multipoles can be well described up to $\sim$185 MeV with Taylor expansions in the partial waves up to first order in pion energy.Comment: 6 pages, 5 figures, version to be published in Physics Letters

H−H-convergence result for nonlocal elliptic-type problems via Tartar's method

In this work we obtain a compactness result for the $H-$convergence of a family of nonlocal and nonlinear monotone elliptic-type problems by means of Tartar's method of oscillating test functions.Comment: In this revision we added a new section that shows the Gamma-convergence of the associated energy functional

Temperature-dependent ion mixing and diffusion during sputtering of thin films of CrSi_2 on silicon

Measurements of sputtering yields and composition profiles have been carried out using backscattering spectrometry for samples of CrSi_2 on Si irradiated with 200‐keV Xe ions. When the CrSi_2 layer is thinner than the ion range, the sputtering yield ratio of Si to Cr increases from 3.5 for room‐temperature irradiation to 65 at 290 °C. For a thick sample, the corresponding increase is from 2.4 to 4.0. only. These changes are explained in terms of a rise in the Si surface concentration at 290 °C. The driving force for this process seems to be the establishment of stoichiometric CrSi_2 compound. Transport of Si to the surface is by ion mixing in the thin sample and thermal diffusion through the thick layer