Constraining spacetime nonmetricity with neutron spin rotation in liquid 4He

General spacetime nonmetricity coupled to neutrons is studied. In this context, it is shown that certain nonmetricity components can generate a rotation of the neutron's spin. Available data on this effect obtained from slow-neutron propagation in liquid helium are used to constrain isotropic nonmetricity components at the level of GeV. These results represent the first limit on the nonmetricity parameter as well as the first measurement of nonmetricity inside matter.DOE/DE-SC0010120NSF/PHY-1614545IU Center for Spacetime SymmetriesNational Science Foundation of China/11605056Chinese Scholarship CouncilAlexander von Humboldt Foundatio

Whole genome sequencing of a banana wild relative Musa itinerans provides insights into lineage-specific diversification of the Musa genus

Crop wild relatives are valuable resources for future genetic improvement. Here, we report the de novo genome assembly of Musa itinerans, a disease-resistant wild banana relative in subtropical China. The assembled genome size was 462.1 Mb, covering 75.2% of the genome (615.2Mb) and containing 32, 456 predicted protein-coding genes. Since the approximate divergence around 5.8 million years ago, the genomes of Musa itinerans and Musa acuminata have shown conserved collinearity. Gene family expansions and contractions enrichment analysis revealed that some pathways were associated with phenotypic or physiological innovations. These include a transition from wood to herbaceous in the ancestral Musaceae, intensification of cold and drought tolerances, and reduced diseases resistance genes for subtropical marginally distributed Musa species. Prevalent purifying selection and transposed duplications were found to facilitate the diversification of NBS-encoding gene families for two Musa species. The population genome history analysis of M. itinerans revealed that the fluctuated population sizes were caused by the Pleistocene climate oscillations, and that the formation of Qiongzhou Strait might facilitate the population downsizing on the isolated Hainan Island about 10.3 Kya. The qualified assembly of the M. itinerans genome provides deep insights into the lineage-specific diversification and also valuable resources for future banana breeding

A failure study of the railway rail serviced for heavy cargo trains

AbstractIn this case study, a failed railway rail which was used for heavy cargo trains was investigated in order to find out its root cause. The macroscopic beach marks and microscopic fatigue striations were not observed by macro and microscopic observations. The chevron patterns were observed by macro observations. The crack origin was at the tip of chevron patterns. The fan-shaped patterns, cleavage step and the river patterns were observed at the crack origin, which demonstrated the feature of cleavage fracture. The metallurgical structures at the crack origin were pearlite and ferrite networks. The crack is supposed to be initiated from the weaker ferrite networks. Given all of that, the failed railway rail is considered to be caused by overload. It is of great importance to improve the welding technology, and control the load of train in order to prevent similar failure in future

VERIFICATION AND VALIDATION OF CONSEQUENCE MODELS FOR ACCIDENTAL RELEASES OF TOXIC OR FLAMMABLE CHEMICALS TO THE ATMOSPHERE

PresentationConsequence modelling software for accidental releases of flammable or toxic chemicals to the atmosphere includes discharge modelling, atmospheric dispersion modelling and evaluation of flammable and toxic effects: - First discharge calculations are carried out to set release characteristics for the hazardous chemical (including depressurisation to ambient). Scenarios which may be modelled includes releases from vessels (leaks or catastrophic ruptures), short pipes or long pipes. Releases considered include releases of sub-cooled liquid, superheated liquid or vapour; un-pressurised or pressurised releases; and continuous, time-varying or instantaneous releases. - Secondly dispersion calculations are carried out to determine the concentrations of the hazardous chemical when the cloud travels in the downwind direction. This includes modelling jet, heavy-gas and passive dispersion regimes, and transitions between them. In the case of a two-phase release, liquid droplet modelling is required to calculate liquid rainout, subsequent pool formation/spreading and re-evaporation from the pool back to the cloud. For heavy-gas releases, effects of crosswind and downwind gravity spreading are present, while for short duration and time-varying releases effects of along-wind diffusion are relevant.. For pressurised instantaneous releases an initial phase of energetic expansion of the cloud occurs. Also, effects of indoor mixing (for indoor releases) and building wakes can be accounted for. - Finally, toxic or flammable calculations are carried out. For flammables, ignition may lead to rising fireballs (instantaneous releases), jet fires possibly impinging on the ground (pressurised flammable releases), pool fires (after rainout) and vapour cloud fires or explosions. Radiation calculations are carried out for fires, while overpressure calculations are carried out for explosions. For each event, the probability of death is determined using toxic or flammable probit functions. Testing of the software should ideally include for each consequence model “verification” that the code correctly solves the mathematical model (i.e. that the calculated variables are a correct solution of the equations), “validation” against experimental data to show how closely the mathematical model agrees with the experimental results, and a “sensitivity analysis” including a large number of input parameter variations to ensure overall robustness of the code, and to understand the effect of parameter variations on the model predictions. The current paper includes an overview on how the above verification and validation could be carried out for these consequence models. Reference is made to the literature for the availability of experimental data. Thus, an extensive experimental database has been developed including experimental data for validation for the above models and scenarios, where many different chemicals are considered (including water, LNG, propane, butane, ethylene, ammonia, CO2, hydrogen, chlorine, HF etc.). The above verification and validation is illustrated by means of application to the latest consequence models in the hazard assessment package Phast and the risk analysis package Safeti

Growth of High Quality ZnMgO Films on Diamond Substrates

AbstractZnMgO films were prepared at room temperature on freestanding diamond (FSD) substrates by co-sputtering. The Mg content was controlled by varying RF sputtering power of MgO and the effects of Mg contents on the properties of ZnMgO films were investigated. The results showed that the (0002) peak of ZnMgO shifted from 34.5° to 35.6° with the increasing sputtering power of MgO target. The UV-visible and PL spetra of ZnMgO films revealed that the bandgap of ZnMgO was approximately linear related to the sputtering power of MgO target

A low-cost metastable beta Ti alloy with high elastic admissible strain and enhanced ductility for orthopaedic application

In this work, a low-cost biomedical titanium alloy Ti–5Mo–Fe–3Sn (atomic percent) was successfully developed. The microstructure, tensile properties and deformation behaviour were investigated at ambient temperature. It was found that the combined addition of Sn and Fe suppressed the formation of athermal omega phase and introduced solid solution strengthening. An excellent combination of low elastic modulus (52 GPa) and high yield strength (740 MPa) was achieved, leading to a high elastic admissible strain (1.42%). Transmission electron microscopy results revealed that with an increase in tensile strain, the {332} twin system was initiated first, and then secondary {332} twinning and ternary {112} twinning were also observed. The evolution of multi-twin system during deformation was responsible for the enhanced strain hardening rate and plasticity (elongation ∼30%)

City branding in China's Northeastern region

The past decade has seen a surge in the use of city branding, which is used to attract specific target groups of investors, high-tech green firms and talented workforce and reflects a desired shift from old, polluting manufacturing industries to new, clean service industries. Previous studies in the Chinese mega-city regions Pearl River Delta, Yangtze River Delta a

Enhanced electrical and optical properties of room temperature deposited Aluminium doped Zinc Oxide (AZO) thin films by excimer laser annealing

High quality transparent conductive oxides (TCOs) often require a high thermal budget fabrication process. In this study, Excimer Laser Annealing (ELA) at a wavelength of 248 nm has been explored as a processing mechanism to facilitate low thermal budget fabrication of high quality aluminium doped zinc oxide (AZO) thin films. 180 nm thick AZO films were prepared by radio frequency magnetron sputtering at room temperature on fused silica substrates. The effects of the applied RF power and the sputtering pressure on the outcome of ELA at different laser energy densities and number of pulses have been investigated. AZO films deposited with no intentional heating at 180 W, and at 2 mTorr of 0.2% oxygen in argon were selected as the optimum as-deposited films in this work, with a resistivity of 1×10−3 Ω.cm, and an average visible transmission of 85%. ELA was found to result in noticeably reduced resistivity of 5×10−4 Ω.cm, and enhancing the average visible transmission to 90% when AZO is processed with 5 pulses at 125 mJ/cm2. Therefore, the combination of RF magnetron sputtering and ELA, both low thermal budget and scalable techniques, can provide a viable fabrication route of high quality AZO films for use as transparent electrodes

Effect of Sun and Planet-Bound Dark Matter on Planet and Satellite Dynamics in the Solar System

We apply our recent results on orbital dynamics around a mass-varying central body to the phenomenon of accretion of Dark Matter-assumed not self-annihilating-on the Sun and the major bodies of the solar system due to its motion throughout the Milky Way halo. We inspect its consequences on the orbits of the planets and their satellites over timescales of the order of the age of the solar system. It turns out that a solar Dark Matter accretion rate of \approx 10^-12 yr^-1, inferred from the upper limit \Delta M/M= 0.02-0.05 on the Sun's Dark Matter content, assumed somehow accumulated during last 4.5 Gyr, would have displaced the planets faraway by about 10^-2-10^1 au 4.5 Gyr ago. Another consequence is that the semimajor axis of the Earth's orbit, approximately equal to the Astronomical Unit, would undergo a secular increase of 0.02-0.05 m yr^-1, in agreement with the latest observational determinations of the Astronomical Unit secular increase of 0.07 +/- 0.02 m yr^-1 and 0.05 m yr^-1. By assuming that the Sun will continue to accrete Dark Matter in the next billions year at the same rate as in the past, the orbits of its planets will shrink by about 10^-1-10^1 au (\approx 0.2-0.5 au for the Earth), with consequences for their fate, especially of the inner planets. On the other hand, lunar and planetary ephemerides set upper bounds on the secular variation of the Sun's gravitational parameter GM which are one one order of magnitude smaller than 10^-12 yr^-1. Dark Matter accretion on planets has, instead, less relevant consequences for their satellites. Indeed, 4.5 Gyr ago their orbits would have been just 10^-2-10^1 km wider than now. (Abridged)Comment: LaTex2e, 17 pages, no figures, 7 tables, 61 references. Small problem with a reference fixed. To appear in Journal of Cosmology and Astroparticle Physics (JCAP