CO2 sensing with chemoresistive Nd2O2CO3 sensors - Operando insights

AbstractIn this work the sensing of Nd2O2CO3-based chemoresistive CO2 sensor was investigated combining DRIFT and DC-resistance measurements. Besides the already reported effect of CO2 exposure, we found that exposure to CO determines comparable effects and that the presence of oxygen in the background is not important. The humidity significantly influences the response for both gases. The spectroscopic results reveal that the exposure to both CO and CO2 consumes the water-related surface species – the rooted-hydroxyls being the electrically active one – and increases the concentration of carbonates; the decrease of the rooted-hydroxyls is probably the cause of the resistance increase

Rare earth oxycarbonates as a material class for chemoresistive CO2 gas sensors

AbstractIn this work we compare the CO2 gas sensing properties of two new materials synthesized from rare earth hydroxide (La(OH)3,Pr(OH)3) precursors, with the already reported ones for neodymium oxycarbonate, which was synthesized from the corresponding Nd(OH)3 precursor. In-situ XRD measurements show that by following similar thermal treatment, praseodymium hydroxide is transforming to the metal oxide while lanthanum hydroxide forms an oxycarbonate, like in the case of neodymium. The chemoresistive effects we found for the lanthanum oxycarbonate were even higher than the ones recorded for the neodymium oxycarbonate; for the praseodymium metal oxide we could not find any CO2 sensitivity. Accordingly, we think that the condition for CO2 sensing is the formation of the rare earth oxycarbonate

The ground state of binary systems with a periodic modulation of the linear coupling

We consider a quasi-one-dimensional two-component systm, described by a pair of Nonlinear Schr\"{o}dinger/Gross-Pitaevskii Equations (NLSEs/GPEs), which are coupled by the linear mixing, with local strength $\Omega$, and by the nonlinear incoherent interaction. We assume the self-repulsive nonlinearity in both components, and include effects of a harmonic trapping potential. The model may be realized in terms of periodically modulated slab waveguides in nonlinear optics, and in Bose-Einstein condensates too. Depending on the strengths of the linear and nonlinear couplings between the components, the ground states (GSs) in such binary systems may be symmetric or asymmetric. In this work, we introduce a periodic spatial modulation of the linear coupling, making $\Omega$ an odd, or even function of the coordinate. The sign flips of $\Omega (x)$ strongly modify the structure of the GS in the binary system, as the relative sign of its components tends to lock to the local sign of $\Omega$. Using a systematic numerical analysis, and an analytical approximation, we demonstrate that the GS of the trapped system contains one or several kinks (dark solitons) in one component, while the other component does not change its sign. Final results are presented in the form of maps showing the number of kinks in the GS as a function of the system's parameters, with the odd/even modulation function giving rise to the odd/even number of the kinks. The modulation of $\Omega (x)$ also produces a strong effect on the transition between states with nearly equal and strongly unequal amplitudes of the two components.Comment: 8 pages, 3 figure

Injuries Following Implementation of a Progressive Load Carriage Program in United States Marine Corps Training

PURPOSE: The overall physical demands placed on recruits completing United States Marine Corps (USMC) training is high and comes concomitantly with high rates of injuries. Load carriage with heavy loads is of particular concern. However, load carriage conditioning, if optimised, can reduce injury risk. METHODS: Retrospective injury data of recruits completing training informed this study. Data were drawn from recruits completing an original load carriage (OLC) program (n=2,363) and those completing a modified load carriage (LCMOD) program (n=681). Musculoskeletal injury data were drawn from the USMC San Diego sports medicine injury database. A population estimate of the OLC:LCMOD relative risk ratio (RR) was calculated. RESULTS: The proportion of injuries sustained by the LCMOD cohort (n=268; 39%) was notably lower than that sustained by the OLC cohort (n=1,372; 58%). The reoccurrence rate *f injury for LCMOD soldiers compared to the OLC was 0.68 (95% CI 0.61 to 0.75). The leading nature of injury (i.e., sprains and strains) was consistent between both cohorts (OLC: n=396; 29% vs. LCMOD: n=66; 25%). Inflammation (n=172; 13%) and fractures (n=144; 11%) were next most common for OLC recruits; while pain (n=58; 22%) and medial tibial stress syndrome (n=18; 8%) were next most common for LCMOD recruits. While stress reactions were proportionally higher in LCMOD (n=17; 6%) when compared to OLC (n=4; 0.3%), stress fractures were proportionality lower (LCMOD: n=9; 3% vs. OLC: n=114; 8%). Pre-existing / chronic injuries were higher in LCMOD (+5%) while new overuse injuries were lower (-7%). Totalling 65% (OLC) and 70% (LCMOD) of reported injuries the knee, lower leg, ankle, and foot were the top 4 bodily sites of injuries, although there were variations in the orders of presentations (See Table 1 for top 10 bodily sites). RELEVANCE: Careful periodisation and planning of a load carriage program can reduce injuries without reducing training outcomes

In-depth mesocrystal formation analysis of microwave-assisted synthesis of LiMnPO4nanostructures in organic solution

In the present work, we report on the preparation of LiMnPO4 (lithiophilite) nanorods and mesocrystals composed of self-assembled rod subunits employing microwave-assisted precipitation with processing times on the time scale of minutes. Starting from metal salt precursors and H3PO4 as phosphate source, single-phase LiMnPO4 powders with grain sizes of approx. 35 and 65 nm with varying morphologies were obtained by tailoring the synthesis conditions using rac-1-phenylethanol as solvent. The mesocrystal formation, microstructure and phase composition were determined by electron microscopy, nitrogen physisorption, X-ray diffraction (including Rietveld refinement), dynamic light scattering, X-ray absorption and X-ray photoelectron spectroscopy, and other techniques. In addition, we investigated the formed organic matter by gas chromatography coupled with mass spectrometry in order to gain a deeper understanding of the dissolution\u2013precipitation process. Also, we demonstrate that the obtained LiMnPO4 nanocrystals can be redispersed in polar solvents such as ethanol and dimethylformamide and are suitable as building blocks for the fabrication of nanofibers via electrospinning

Disorder-Induced Order in Quantum XY Chains

We observe signatures of disorder-induced order in 1D XY spin chains with an external, site-dependent uni-axial random field within the XY plane. We numerically investigate signatures of a quantum phase transition at T=0, in particular an upsurge of the magnetization in the direction orthogonal to the external magnetic field, and the scaling of the block-entropy with the amplitude of this field. Also, we discuss possible realizations of this effect in ultra-cold atom experiments

Origin of intragranular crystallographic misorientations in hot-dip Al-Zn-Si coatings

The origin of intragranular variations of the crystallographic orientation in hot-dip Al-Zn-Si coatings is discussed based on new experimental results and modelling. The solidification microstructure in as-received 55Al-43.4Zn-l.6Si (in wt.%) coatings deposited on steel plates in an industrial production line was analyzed by electron backscattered diffraction, glow-discharge optical emission spectroscopy and atomic force microscopy (AFM). The results were compared with those obtained in coatings re-solidified under different cooling and mechanical loading conditions. Continuous variations of the crystallographic orientation as large as 35 degrees were observed within individual grains of Al-Zn-Si, consistent with previous Studies. However, the mechanisms previously proposed for the origin of intragranular crystallographic misorientations had to be revisited. The new experimental data acquired during this study indicate that the solidification shrinkage accumulating in the area of the grain envelope is the driving Force for the formation of intragranular misorientations. The solidification shrinkage leads to the development of tensile stresses in the oxide film covering the coating while it solidifies. Estimations based on AFM profiles and phase field Simulations of the dendritic structure indicate that the stresses applied on the dendrite network are sufficient to deform plastically the dendrite arms during solidification. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

Gender differences in injuries sustained during United States Marine Corps training

Aim: To investigate gender-specific differences in injuries in United States Marine Corps (USMC) trainees.Design: Retrospective cohort study.Method: Point-of-care injury data for USMC recruits (females=94; males=681) completing training were drawn from the Marine Corps Recruit Depot San Diego sports medicine injury database and analysed descriptively. The male: female incidence rate ratio (IRR) was calculated.Results: Male trainees suffered more injuries (male=268; 39%; female n=22; 23%; IRR=1.68 (95% CI 1.33 to 2.1)). Sprains and strains were the leading nature of injury (female=41%; male=25%) followed by pain(female=23%; male=22%). The leading type of injury was ‘new overuse injuries’ for both genders (54% each). Female trainees experienced more acute injuries (36% versus 26%). While female (55%) and male (58%)rates of ‘moderate’ injuries were similar, female trainees experienced more ‘mild’ injuries (36% versus 25%). The knee (female=27%: male=23%) and lower leg (female=23%: male=21%) were the leading injury sites. All injuries were to the lower limbs in female trainees; male trainees also reported injuries to the upper limb (12%) and trunk (8%).Conclusion: Female trainees experienced fewer injuries than male trainees, with more being mild. Both genders had similar natures of injuries in similar body sites except that male trainees reported some upper body and trunk injuries.</div