215 research outputs found

    Fe-P and Fe-P-Pt co-deposits as hydrogen electrodes in alkaline solution

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    Fe-P and Fe-P-Pt alloys for use as electrodes for alkaline water electrolysis are prepared by an electroplating technique which employs an acidic complex bath solution. After heat treatment, the plated alloys act as effective electrocatalytic materials by lowering the hydrogen overpotential sufficiently. The improved electrocatalytic activity is due to an increase in effective surface area, a change in surface features upon heat treatment, and the presence of traces of platinum. Electrodes of the plated alloys are stable even in a highly corrosive electrolytic medium (6 M KOH). © 2001 Elsevier Science B.V. All rights reserved

    Substrate utilization in man: effects of dietary fat and carbohydrate

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    Substrate utilization in man: effects of dietary fat and carbohydrate. Verboeket-van de Venne WP, Westerterp KR, ten Hoor F. Department of Human Biology, University of Limburg, Maastricht, The Netherlands. In man there is evidence that the ability to adjust fat oxidation to fat intake is less effective than the ability to adjust carbohydrate and protein oxidation to carbohydrate and protein intake. The short-term (3-day) effects of a low-fat (LF), mixed (M), and high-fat (HF) diet on human substrate balances were studied using a respiration chamber. Subjects were 14 young female students classified by means of their scores on psychometric questionnaires as "restrained" or "unrestrained" eaters. Subjects were in energy balance, ie, the mean difference between energy intake (EI) and energy expenditure (EE) was 86 +/- 85 kJ/d. The fat content of the food significantly influence the 24-hour respiratory quotient (RQ) and nonprotein respiratory quotient (NPRQ). For both the LF and M diets, the 24-hour RQ was significantly lower than the food quotient (FQ), whereas the RQ on the HF diet was not different from the FQ. Oxidation of fat and carbohydrate significantly increased with, respectively, an increasing fat and carbohydrate content of the diet for both restrained- and unrestrained-eating subjects. Restrained-eating subjects showed a decreased fat oxidation compared with unrestrained eaters in response to a HF diet, resulting in a positive fat balance for restrained-eating subjects. On a LF diet, fat balance was negative for both groups of subjects, indicating net endogenous fat oxidation. In conclusion, restrained-eating subjects have more difficulty in the handling of a HF diet, possibly explaining their higher susceptibility to becoming obes

    A convolution of observational and model data to estimate age of air spectra in the northern hemispheric lower stratosphere

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    Derivation of mean age of air (AoA) and age spectra from atmospheric measurements remains a challenge and often requires output from atmospheric models. This study tries to minimize the direct influence of model output and presents an extension and application of a previously established inversion method to derive age spectra from mixing ratios of long- and short-lived trace gases. For a precise description of cross-tropopause transport processes, the inverse method is extended to incorporate air entrainment into the stratosphere across the tropical and extratropical tropopause. We first use simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS) to provide a general proof of concept of the extended principle in a controllable and consistent environment, where the method is applied to an idealized set of 10 trace gases with predefined constant lifetimes and compared to reference model age spectra. In the second part of the study we apply the extended inverse method to atmospheric measurements of multiple long- and short-lived trace gases measured aboard the High Altitude and Long Range (HALO) research aircraft during the two research campaigns POLSTRACC–GW-LCYCLE–SALSA (PGS) and Wave-driven Isentropic Exchange (WISE). As some of the observed species undergo significant loss processes in the stratosphere, a Monte Carlo simulation is introduced to retrieve age spectra and chemical lifetimes in stepwise fashion and to account for the large uncertainties. Results show that in the idealized model scenario the inverse method retrieves age spectra robustly on annual and seasonal scales. The extension to multiple entry regions proves reasonable as our CLaMS simulations reveal that in the model between 50 % and 70 % of air in the lowermost stratosphere has entered through the extratropical tropopause (30–90∘ N and S) on annual average. When applied to observational data of PGS and WISE, the method derives age spectra and mean AoA with meaningful spatial distributions and quantitative range, yet large uncertainties. Results indicate that entrainment of fresh tropospheric air across both the extratropical and tropical tropopause peaked prior to both campaigns, but with lower mean AoA for WISE than PGS data. The ratio of moments for all retrieved age spectra for PGS and WISE is found to range between 0.52 and 2.81 years. We conclude that the method derives reasonable and consistent age spectra using observations of chemically active trace gases. Our findings might contribute to an improved assessment of transport with age spectra in future studies

    Article in De Hollander

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    In this issue of De Hollander, there appeared a long article, entitled, Is the matter of John Roost now completely settled? Roost was involved in a court case. [I believe it was concerning his alleged withholding of some funds he raised in the East for the Holland Harbor. The minutes of the board of Holland Township would have much information on this issue.] F. J. Littlejohn, Circuit Register, was quoted. Kommer Schaddelee was mentioned in passing.https://digitalcommons.hope.edu/vrp_1860s/1082/thumbnail.jp

    Satellite measurements of formaldehyde linked to shipping emissions

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    International shipping is recognized as a pollution source of growing importance, in particular in the remote marine boundary layer. Nitrogen dioxide originating from ship emissions has previously been detected in satellite measurements. This study presents the first satellite measurements of formaldehyde (HCHO) linked to shipping emissions as derived from observations made by the Global Ozone Monitoring Experiment (GOME) instrument. <br><br> We analyzed enhanced HCHO tropospheric columns from shipping emissions over the Indian Ocean between Sri Lanka and Sumatra. This region offers good conditions in term of plume detection with the GOME instrument as all ship tracks follow a single narrow track in the same east-west direction as used for the GOME pixel scanning. The HCHO signal alone is weak but could be clearly seen in the high-pass filtered data. The line of enhanced HCHO in the Indian Ocean as seen in the 7-year composite of cloud free GOME observations clearly coincides with the distinct ship track corridor from Sri Lanka to Indonesia. The observed mean HCHO column enhancement over this shipping route is about 2.0×10<sup>15</sup> molec/cm<sup>2</sup>. <br><br> Compared to the simultaneously observed NO<sub>2</sub> values over the shipping route, those of HCHO are substantially higher; also the HCHO peaks are found at larger distance from the ship routes. These findings indicate that direct emissions of HCHO or degradation of emitted NMHC cannot explain the observed enhanced HCHO values. One possible reason might be increased CH<sub>4</sub> degradation due to enhanced OH concentrations related to the ship emissions, but this source is probably too weak to fully explain the observed values. <br><br> The observed HCHO pattern also agrees qualitatively well with results from the coupled earth system model ECHAM5/MESSy applied to atmospheric chemistry (EMAC). However, the modelled HCHO values over the ship corridor are two times lower than in the GOME high-pass filtered data. This might indicate uncertainties in the satellite data and used emission inventories and/or that the in-plume chemistry taking place in the narrow path of the shipping lanes are not well represented at the rather coarse model resolution

    Aerobic and strength exercises for youngsters aged 12 to 15: what do parents think?

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    BACKGROUND: Although strength exercises evidently have both physiological and psychological health benefits across all ages, they are erroneously considered to adversely affect health status in youngsters. The aim of this study was to examine parental attitudes towards their child's physical activity in general, as well as aerobic and strength exercises in particular. METHODS: In total, 314 parents from an online panel representative of the Dutch population completed an online survey about their own physical activity and that of their child (12-15 years old). The study also explored reasons for non-participation, and attitudes about the parents' own and their child's physical activity level. RESULTS: Parents consistently reported a positive attitude towards aerobic exercises, but a less positive attitude regarding strength exercises. Parents were more likely to indicate that their child was not allowed to participate in strength exercises (29.6 %) than aerobic exercises (4.0 %). They thought that strength exercises could interfere with optimal physical development. CONCLUSIONS: This study consistently shows that parents have a positive attitude towards aerobic exercises, but a less positive attitude regarding strength exercises. We suggest testing interventions to increase parental understanding of the advantages of and possibilities for (e.g., facilities) strength training on their child's health

    Depletion of Ozone and Reservoir Species of Chlorine and Nitrogen Oxide in the Lower Antarctic Polar Vortex Measured from Aircraft

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    Novel airborne in situ measurements of inorganic chlorine, nitrogen oxide species, and ozone were performed inside the lower Antarctic polar vortex and at its edge in September 2012. We focus on one flight during the Transport and Composition of the LMS/Earth System Model Validation (TACTS/ESMVal) campaign with the German research aircraft HALO (High-Altitude LOng range research aircraft), reaching latitudes of 65°S and potential temperatures up to 405 K. Using the early winter correlations of reactive trace gases with N2O from the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS), we find high depletion of chlorine reservoir gases up to ∼40% (0.8 ppbv) at 12 km to 14 km altitude in the vortex and 0.4 ppbv at the edge in subsided stratospheric air with mean ages up to 4.5 years. We observe denitrification of up to 4 ppbv, while ozone was depleted by 1.2 ppmv at potential temperatures as low as 380 K. The advanced instrumentation aboard HALO enables high-resolution measurements with implications for the oxidation capacity of the lowermost stratosphere. ©2017. American Geophysical Union
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