The relevance of particulate organic carbon (POC) for carbon composition in the pore water of drained and rewetted fens of the "Donauried" (South-Germany)

International audienceNumerous studies have dealt with carbon (C) concentrations in Histosols, but there are no studies quantifying the relative importance of all individual C components in pore waters. For this study, measurements were made of all the carbon components (i.e., particulate organic carbon, POC; dissolved organic carbon, DOC; dissolved inorganic carbon, DIC; dissolved methane, CH4) in the soil pore water of a calcareous fen under three different water management regimes (re-wetted, deeply and moderately drained). Pore water was collected weekly or biweekly (April 2004 to April 2006) at depths between 10 and 150 cm. The main results obtained were: (1) DIC (94?280 mg C l?1) was the main C-component. (2) POC and DOC concentrations in the pore water (14?125 mg C l?1 vs. 41?95 mg C l?1) were pari passu. (3) Dissolved CH4 was the smallest C component (0.005?0.9 mg C l?1). Interestingly, about 30% of the POM particles were colonized by microbes indicating that they are active in the internal C transfer in the soil profile ("C-Shuttles"). Consequently, it was concluded that POC is at least as important as DOC for internal soil C turnover. There is no reason to assume significant biochemical differences between POC and DOC as they only differ in size. Therefore, both POC and DOC fractions are essential components of C budgets of peatlands. Furthermore dissolved CO2 in all forms of DIC apparently is an important part of peatland C-balances

Thermal benchmark of a classic and novel embedded high-power 3-phase inverter Bridge

A 3-phase high power inverter bridge for a 500 W PEDELEC motor fabricated using a novel embedding technology was benchmarked against a classically designed module using MOSFETs in a B6 Bridge. By operating each MOSFET individually in reverse mode and measuring the forward voltage during high current operation and after switching to a measuring current of 50 mA the junction temperature has been measured. Equivalent thermal resistances used for comparison have been calculated. By reverse modelling the thermal behaviour of the entire module including the MOSFETs' junction temperatures at full operation has been established. The study is extended to an embedded 50kW-demonstrator design for electric vehicle applications where the thermal resistances were studied and the maximum allowable boundary conditions predicted by simulation

Occurrence of Fusaproliferin and Beauvericin in Fusarium-Contaminated Livestock Feed in Iowa

Fusarium fungal contaminants and related mycotoxins were investigated in eight maize feed samples submitted to the Iowa State University Veterinary Diagnostic Laboratory. Fusarium moniliforme, F. proliferatum, and F. subglutinans were isolated from seven, eight, and five samples, respectively. These strains belonged to mating populations A, D, and E of the teleomorph Gibberella fujikuroi. Fusaproliferin was detected at concentrations of 0.1 to 30 μg/g in four samples, and beauvericin was detected (0.1 to 3.0 μg/g) in five samples. Fumonisins were detected in all eight samples (1.1 to 14 μg/g). Ten of 11 strains of F. proliferatum and all 12 strains of F. subglutinans isolated from the samples produced fusaproliferin in culture on whole maize kernels (4 to 350 and 100 to 1,000 μg/g, respectively). Nine F. proliferatum strains also produced beauvericin in culture (85 to 350 μg/g), but none of the F. subglutinans strains produced beauvericin. Fumonisin B(1) was produced by all nine F. moniliforme strains (50 to 2,000 μg/g) and by 10 of the F. proliferatum strains (1,000 to 2,000 μg/g). This is the first report of the natural occurrence of fusaproliferin outside Italy and of the natural occurrence of beauvericin in North America

Thermal Analysis of Multilayer Printed Circuit Boards with Embedded Carbon Black-Polymer Resistors

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