Full scale phosphoric acid fuel cell stack technology development

The technology development for phosphoric acid fuel cells is summarized. The preparation, heat treatment, and characterization of carbon composites used as bipolar separator plates are described. Characterization included resistivity, porosity, and electrochemical corrosion. High density glassy carbon/graphite composites performed well in long-term fuel cell endurance tests. Platinum alloy cathode catalysts and low-loaded platinum electrodes were evaluated in 25 sq cm cells. Although the alloys displayed an initial improvement, some of this improvement diminished after a few thousand hours of testing. Low platinum loading (0.12 mg/sq cm anodes and 0.3 mg/sq cm cathodes) performed nearly as well as twice this loading. A selectively wetproofed anode backing paper was tested in a 5 by 15 inch three-cell stack. This material may provide for acid volume expansion, acid storage, and acid lateral distribution

Strontium Isotope Composition and Trace Element Concentrations in Lake Huron and its Principal Tributaries

(print) ix, 109 p. : ill., maps ; 28 cm.Concentrations of the major cations: Na, K, Ca, Mg and Sr were determined for 64 samples of surface water from Lake Huron and for 17 of its major tributary rivers. For addition, isotopic compositions of strontium were measured for 30 samples of lake water and for 13 of the tributary rivers. Concentrations of dissolved iron and total phosphorus were determined for a small suite of lake and river water. The data document important differences in the chemical composition of water discharged into Lake Huron by Lake Superior, Lake Michigan and tributary rivers. These differences are related to differences in the chemical and mineralogical composition of the bedrock underlying the Great Lakes drainage basin. The strontium contributed to Lake Huron by water draining the Canadian Shield along its northern shore is enriched in radiogenic Sr87. The average Sr87/ Sr86 ratio is 0. 718. The rivers draining sedimentary rocks of Michigan and southwestern Ontario contribute strontium whose isotope composition is similar to that in the modern oceans and has a Sr87/Sr86 ratio of 0.710. A geochemical model is presented which attempts to represent the chemical composition of water in Lake Huron as a mixture of the different types of water discharged by different sources.Abstract -- Statement of the Significance and Applicability of the Results -- Table of Contents -- List of Tables -- List of Figures -- Acknowledgments -- Introduction -- Collection of Water Samples -- Analytical Methods -- Precision and Accuracy -- Presentation and Discussion of the Results -- Formulation of a Model for the Chemical Composition of Lake Huron -- The Isotope Composition of Strontium in the Great Lakes -- Summary and Conclusions -- References -- Geochemical Aspects of the Scioto and Olentangy Rivers, Columbus, Ohi

Methodology for Detecting Trace Amounts of Microchimeric DNA from Peripheral Murine White Blood Cells by Real-Time PCR

Real-time PCR methodology can successfully quantitate microchimeric cell populations at a concentration of 100 microchimeric cells/100,000 host cells; however, it has not been successful in quantitating DNA from trace numbers of microchimeric white blood cells which we reported are present in murine peripheral blood at a concentration as low as 2/100,000 host cells. We report methodology using primers for a portion of the H2-k(b) murine histocompatibility sequence, specific for the C57BL/6J mouse. When these primers were used in the presence of 11,000 μM primer, a 20-fold increase in the median manufacturer’s recommended concentration, the assay could be optimized to detect 34 pg of C57BL/6J DNA in a background of 2.5 μg of carrier BALB/cJ DNA (1/100,000). These conditions resulted in a detection limit half as sensitive as that found when no carrier DNA was present

A tandem duplication within the fibrillin 1 gene is associated with the mouse tight skin mutation.

Mice carrying the Tight skin (Tsk) mutation have thickened skin and visceral fibrosis resulting from an accumulation of extracellular matrix molecules. These and other connective tissue abnormalities have made Tskl + mice models for scleroderma, hereditary emphysema, and myocardial hypertrophy. Previously we localized Tsk to mouse chromosome 2 in a region syntenic with human chromosome 15. The microfibrillar glycoprotein gene, fibrillin 1 (FBN1), on human chromosome 15q, provided a candidate for the Tsk mutation. We now demonstrate that the Tsk chromosome harbors a 30- to 40-kb genomic duplication within the Fbn1 gene that results in a larger than normal in-frame Fbn1 transcript. These findings provide hypotheses to explain some of the phenotypic characteristics of Tskl + mice and the lethality of Tsk/Tsk embryos

Prevention for oneself or others? Psychological and social factors that explain social distancing during the COVID-19 pandemic

Identifying the underlying psychological and social factors of social distancing is crucial to foster preventive behavior during a pandemic effectively. We investigated the relative contribution of self-focused factors (fear of infection, fear of punishment) and other-focused factors (moral judgment, moral identity, empathy for unspecific others, empathy for loved ones) in an online study in Germany (N = 246) while COVID-19 was climaxing. Importantly, other-oriented factors were related to social distancing behavior beyond self-oriented factors. Moral judgment and empathy for loved ones remained the dominant factors while controlling for all aspects. These findings underline the relevance of interpersonal considerations when engaging in preventive behavior

The influence of snow sublimation and meltwater evaporation on δD of water vapor in the atmospheric boundary layer of central Europe

Post-depositional fractionation of stable water isotopes due to fractionating surface evaporation introduces uncertainty to various isotope applications such as the reconstruction of paleotemperatures, paleoaltimetry, and the investigation of groundwater formation. In this study, we investigate isotope fractionation at snow-covered moisture sources by combining 17 months of observations of isotope concentration ratios [HD16O] ∕ [H216O] in low-level water vapor in central Europe with a new Lagrangian isotope model. The isotope model is capable of reproducing variations of the observed isotope ratios with a correlation coefficient R of 0.82. Observations from 38 days were associated with cold snaps and moisture uptake in snow-covered regions. Deviations between modeled and measured isotope ratios during the cold snaps were related to differences in skin temperatures (Tskin). Analysis of Tskin provided by the Global Data Assimilation System (GDAS) of the NCEP implies the existence of two regimes of Tskin with different types of isotope fractionation during evaporation: a cold regime with Tskin < Tsubl,max = −7.7 °C, which is dominated by non-fractionating sublimation of snow, and a warmer regime with Tsubl,max < Tskin < 0 °C, which is dominated by fractionating evaporation of meltwater. Based on a sensitivity study, we assess an uncertainty range of the determined Tsubl,max of −11.9 to −2.9 °C. The existence of the two fractionation regimes has important implications for the interpretation of isotope records from snow-covered regions as well as for a more realistic modeling of isotope fractionation at snow-covered moisture sources. For these reasons, more detailed experimental studies at snow-covered sites are needed to better constrain the Tsubl,max and to further investigate isotope fractionation in the two regimes

Airborne in situ vertical profiling of HDO/H₂¹⁶O in the subtropical troposphere during the MUSICA remote sensing validation campaign

Vertical profiles of water vapor (H2O) and its isotope ratio D/H expressed as δD(H2O) were measured in situ by the ISOWAT II diode-laser spectrometer during the MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA) airborne campaign. We present recent modifications of the instrument design. The instrument calibration on the ground as well as in flight is described. Based on the calibration measurements, the humidity-dependent uncertainty of our airborne data is determined. For the majority of the airborne data we achieved an accuracy (uncertainty of the mean) of δ(δD) &approx;10&permil;. Vertical profiles between 150 and ∼7000 m were obtained during 7 days in July and August 2013 over the subtropical North Atlantic Ocean near Tenerife. The flights were coordinated with ground-based (Network for the Detection of Atmospheric Composition Change, NDACC) and space-based (Infrared Atmospheric Sounding Interferometer, IASI) FTIR remote sensing measurements of δD(H2O) as a means to validate the remote sensing humidity and δD(H2O) data products. The results of the validation are presented in detail in a separate paper (Schneider et al., 2014). The profiles were obtained with a high vertical resolution of around 3 m. By analyzing humidity and δD(H2O) correlations we were able to identify different layers of air masses with specific isotopic signatures. The results are discussed. © Author(s) 2015