Analysis of biochars for C,H,N,O and S by elemental analyser

[Extract] The basic principles of elemental analysis by dry combustion are straightforward. An accurately weighed aliquot of a sample is combusted to decompose it into gases that are then separated from each other and from other undesired components of the sample. The analytes of interest are then quantified through comparison to standards of known composition and the results presented as a percentage by mass of the original sample

Dielectric properties of thin Cr2O3 films grown on elemental and oxide metallic substrates

In an attempt to optimize leakage characteristics of α-Cr2O3 thin films, its dielectric properties were investigated at local and macroscopic scale. The films were grown on Pd(111), Pt(111), and V2O3 (0001), supported on Al2O3 substrate. The local conductivity was measured by conductive atomic force microscopy mapping of Cr2O3 surfaces, which revealed the nature of defects that formed conducting paths with the bottom Pd or Pt layer. A strong correlation was found between these electrical defects and the grain boundaries revealed in the corresponding topographic scans. In comparison, the Cr2O3 film on V2O3 exhibited no leakage paths at similar tip bias value. Electrical resistance measurements through e-beam patterned top electrodes confirmed the resistivity mismatch between the films grown on different electrodes. The x-ray analysis attributes this difference to the twin free Cr2O3 growth on V2O3 seeding

Perspectives in Fundamental Physics in Space

We discuss the fundamental principles underlying the current physical theories and the prospects of further improving their knowledge through experiments in space.Comment: Gravitational waves, gravitomagnetism, Equivalence Principle, Antimatter, Pioneer Anomaly, Lorentz invariance. To appear in IAA - Acta Astronautica Journal (2006

Proposed astrophysical test of Lorentz invariance

Working in the context of a Lorentz-violating extension of the standard model we show that estimates of Lorentz symmetry violation extracted from ultra-high energy cosmic rays beyond the Greisen-Kuzmin-Zatsepin (GZK) cutoff allow for setting bounds on parameters of that extension. Furthermore, we argue that a correlated measurement of the difference in the arrival time of gamma-ray photons and neutrinos emitted from active galactic nuclei or gamma-ray bursts may provide a signature of possible violation of Lorentz symmetry. We have found that this time delay is energy independent, however it has a dependence on the chirality of the particles involved. We also briefly discuss the known settings where the mechanism for spontaneous violation of Lorentz symmetry in the context of string/M-theory may take place.Comment: Typos corrected. Version to appear in Phys. Rev.

Space-charge limited conduction in epitaxial chromia films grown on elemental and oxide-based metallic substrates

We study temperature dependent (200 – 400 K) dielectric current leakage in high-quality, epitaxial chromia films, synthesized on various conductive substrates (Pd, Pt and V2O3). We find that trap-assisted space-charge limited conduction is the dominant source of electrical leakage in the films, and that the density and distribution of charge traps within them is strongly dependent upon the choice of the underlying substrate. Pd-based chromia is found to exhibit leakage consistent with the presence of deep, discrete traps, a characteristic that is related to the known properties of twinning defects in the material. The Pt- and V2O3-based films, in contrast, show behavior typical of insulators with shallow, exponentially-distributed traps. The highest resistivity is obtained for chromia fabricated on V2O3substrates, consistent with a lower total trap density in these films. Our studies suggest that chromia thin films formed on V2O3 substrates are a promising candidate for next-generation spintronics

Constant Transmission Properties of Variant Creutzfeldt-Jakob Disease in 5 Countries

Variant Creutzfeldt-Jakob disease (vCJD) has been reported in 12 countries. We hypothesized that a common strain of agent is responsible for all vCJD cases, regardless of geographic origin. To test this hypothesis, we inoculated strain-typing panels of wild-type mice with brain material from human vCJD case-patients from France, the Netherlands, Italy, and the United States. Mice were assessed for clinical disease, neuropathologic changes, and glycoform profile; results were compared with those for 2 reference vCJD cases from the United Kingdom. Transmission to mice occurred from each sample tested, and data were similar between non-UK and UK cases, with the exception of the ranking of mean clinical incubation times of mouse lines. These findings support the hypothesis that a single strain of infectious agent is responsible for all vCJD infections. However, differences in incubation times require further subpassage in mice to establish any true differences in strain properties between cases

Vega—A small, low cost, ground robot for nuclear decommissioning

From Wiley via Jisc Publications RouterHistory: received 2021-08-20, rev-recd 2021-11-03, accepted 2021-11-05, pub-electronic 2021-11-25Article version: VoRPublication status: PublishedFunder: Royal Academy of Engineering; Id: http://dx.doi.org/10.13039/501100000287Funder: Engineering and Physical Sciences Research Council; Id: http://dx.doi.org/10.13039/501100000266Abstract: This paper presents the Vega robot, which is a small, low cost, potentially disposable ground robot designed for nuclear decommissioning. Vega has been developed specifically to support characterization and inspection operations, such as 2D and 3D mapping, radiation scans and sample retrieval. The design and construction methodology that was followed to develop the robot is described and its capabilities detailed. Vega was designed to provide flexibility, both in software and hardware, is controlled via tele‐operation, although it can be extended to semi and full autonomy, and can be used in either tethered or untethered configurations. A version of the tethered robot was designed for extreme radiation tolerance, utilizing relay electronics and removing active electronic systems. Vega can be outfitted with a multitude of sensors and actuators, including gamma spectrometers, alpha/beta radiation sensors, LiDARs and robotic arms. To demonstrate its flexibility, a 5 degree‐of‐freedom manipulator has been successfully integrated onto Vega, facilitating deployments where handling is required. To assess the tolerance of Vega to the levels of ionizing radiation that may be found in decommissioning environments, its individual components were irradiated, allowing estimates to be made of the length of time Vega would be able to continue to operate in nuclear environments. Vega has been successfully deployed in an active environment at the Dounreay nuclear site in the UK, deployed in nonactive environments at the Atomic Weapons Establishment, and demonstrated to many other organizations in the UK nuclear industry including Sellafield Ltd, with the goal of moving to active deployments in the future

Determining the lower limit of Liangzhu culture based on black carbon purification with hydropyrolysis technique

Located in the middle and lower reaches of the Yangtze River, the Liangzhu Culture was one of the most important Neolithic cultures at the dawn of Chinese civilization. However, uncertainty over the lower age limit ending the Liangzhu Culture has resulted in a lack of consensus in defining its timespan. In order to establish the lower age limit, a representative site of late Liangzhu Culture, the Bianjiashan wharf, located in Hangzhou City, Zhejiang Province, Eastern China, was selected for investigation. Wooden stakes in the wharf and charcoals in the sediment profile near to the wharf site were collected for 14C AMS dating. To remove any contaminants, the charcoals were pre-treated by catalytic hydropyrolysis (HyPy) to isolate black carbon fractions (BCHyPy). The continuous charcoal age distribution along the vertical profile of the silt core suggests the continual occupation of the Bianjiashan Site and that the site was developed soon after the river formed. The end of river sedimentation indicates that the demise of the Bianjiashan Site occurred no later than Cal BC 2470 (95% probability). The mean age of the more recent calendar calibrated age range BC 2525 for the BCHyPy residue is consistent with earlier evidence. The wharf, as a typical structure of the late Liangzhu Culture, was established between Cal BC 2635 and 2890 (95% probability). The start of the river charcoal sedimentation was found to have a very similar overall age span and, therefore, the river existed at the Bianjiasha Site for no more than a maximum of just over 400 years, which is taken as the maximum period, it was occupied by the Liangzhu population. In comparison to the fresh charcoal samples, the BCHyPy fractions and products were generally found to have similar probability age distributions. GC-MS analysis of the products (non-BCHyPy fractions) released by HyPy indicated that . Tthe exogenous carbon from plants in the charcoal is present as both covalently bonded and adsorbed species, and was deposited at the same time as the charcoal, suggesting that the sediments have been preserved in a closed environment without disturbance as soon as the river ceased to exist. Thus, HyPy has confirms that there was no significant bias in the charcoal radiocarbon ages from more recent sedimentary organic matter

Healing of surgical site after total hip and knee replacements show similar telethermographic patterns

BACKGROUND: Isolated reports indicate the efficacy of infrared thermography for monitoring wound healing and septic complications, but no long-term analysis has ever been performed on this, and there are no data on the telethermographic patterns of surgical site healing after uncomplicated total hip prosthesis and after knee prosthesis. MATERIALS AND METHODS: In this prospective, observational, nonrandomized cohort study, two groups with forty consecutive patients each, who were operated on respectively for total hip and for total knee replacements, underwent telethermographic examination of the operated and contralateral joints prior to and at fixed intervals for up to 1\ua0year after uncomplicated surgery. A digital, portable telethermocamera and dedicated software were used for data acquisition and processing. RESULTS: No thermographic difference was observed preoperatively between the affected side and the contralateral side in both groups. After the intervention, a steep increase in the temperature of the operated joint was recorded after total hip replacement and after knee replacement, with a peak mean differential temperature measured three days postoperatively between the operated and unoperated joint of 3.1\ua0\ub1\ua00.8\ub0C after total hip replacement, and 3.4\ua0\ub1\ua00.7\ub0C after total knee replacement. Thereafter, the mean differential temperature declined slowly to 0.7\ua0\ub1\ua01.1\ub0C and to 0.5\ua0\ub1\ua01.3\ub0C at 60\ua0days, and to 0.0\ua0\ub1\ua01.0\ub0C and -0.1\ua0\ub1\ua01.1\ub0C 90\ua0days post-operatively, respectively. No further changes were observed for up to 1\ua0year after surgery. Results were similar when comparing the average telethermographic values of an elliptical area where the main axis corresponded to the surgical wound. CONCLUSIONS: The surgical sites after uncomplicated total hip or total knee replacement show similar telethermographic patterns for up to 1\ua0year from surgery, and can easily be monitored using a portable, digital, telethermocamera

Some Remarks on Theories with Large Compact Dimensions and TeV-Scale Quantum Gravity

We comment on some implications of theories with large compactification radii and TeV-scale quantum gravity. These include the behavior of high-energy gravitational scattering cross sections and consequences for ultra-high-energy cosmic rays and neutrino scattering, the question of how to generate naturally light neutrino masses, the issue of quark-lepton unification, the equivalence principle, and the cosmological constant.Comment: 28 pages, Late