1,486 research outputs found
On the Use of a Magnetometer to Determine the Angular Motion of a Spinning Body in Regular Precession
Magnetometer for determination of angular motion of spinning body in regular precessio
Economic and Policy Factors Driving the Adoption of Institutional Woody Biomass Heating Systems in the United States
New biomass combustion technologies and adequate biomass supplies have empowered the United States (U.S.) to look beyond satisfying heating needs with traditional fossil-based fuels, but biomass heating is often overlooked by many commercial and institutional entities. This study uses county level Zero Inflated Negative Binomial (ZINB) cross sectional regression analyses to identify economic factors that are favorable to the adoption of decentralized woody biomass heating systems by institutions in the U.S. In addition, biomass policy efficacy with respect to decentralized biomass heating systems is analyzed and regression results are used to develop an expansion map that highlights counties in the U.S. that may be good targets for biomass heating. Across all three models higher heating degree days, population density, and available forest residues decrease the odds of a county not containing an institution using a decentralized biomass heating system, with forest residues being the best predictor. When predicting the likely count of institutions using biomass heating systems, heating degree days, commercial natural gas prices, median house value, available biomass from lands treated under the National Fire Plan, and the proportion of Forest Service land have statistically significant coefficients that are positive. An increase in each of these variables is positively associated with an increased likelihood of one or more institutions using biomass. State policies in support of biomass use were shown to have a negligible effect on the number of decentralized biomass heating systems, while procurement policies related to utility infrastructure and renewable products and fuels specifically have a negative association. It is worth noting that, though level of active management resulting in biomass production is not a policy variable per se, it has important policy dimensions. Both federal land management practices and resources allocated to fuel treatments under NFP are highly subject to public policy decisions, including budget allocations for forest restoration and fuels treatments. Future expansion in the use of decentralized biomass heating systems is predicted to be most successful in counties in the Northwest and Northeast, and to a lesser degree in counties in the states of Michigan, Colorado, and New Mexico
Producing High Concentrations of Hydrogen in Palladium via Electrochemical Insertion from Aqueous and Solid Electrolytes
Metal hydrides are critical materials in numerous technologies including
hydrogen storage, gas separation, and electrocatalysis. Here, using Pd-H as a
model metal hydride, we perform electrochemical insertion studies of hydrogen
via liquid and solid state electrolytes at 1 atm ambient pressure, and achieve
H:Pd ratios near unity, the theoretical solubility limit. We show that the
compositions achieved result from a dynamic balance between the rate of
hydrogen insertion and evolution from the Pd lattice, the combined kinetics of
which are sufficiently rapid that operando experiments are necessary to
characterize instantaneous PdHx composition. We use simultaneous
electrochemical insertion and X-ray diffraction measurements, combined with a
new calibration of lattice parameter versus hydrogen concentration, to enable
accurate quantification of the composition of electrochemically synthesized
PdHx. Furthermore, we show that the achievable hydrogen concentration is
severely limited by electrochemomechanical damage to the palladium and/or
substrate. The understanding embodied in these results helps to establish new
design rules for achieving high hydrogen concentrations in metal hydrides.Comment: 38 page
First Record of \u3ci\u3eOchlerotatus Japonicus\u3c/i\u3e (Diptera: Culicidae) in St. Joseph County, Indiana
A single female specimen of Ochlerotatus japonicus (Theobald)(formerly Aedes japonicus), the Asian bush mosquito, was captured in St. Joseph County, IN on 29 July 2004. This is the first report of that species in northern Indiana. Additional specimens were subsequently collected, indicating probable establishment throughout the county
Fatty Acid Profiles Distinguish Channel Catfish From Three Reaches of the Lower Kaskaskia River and its Floodplain Lakes
Despite the increasing use of fatty acids (FAs) as biomarkers in aquatic food web analysis, little information is available regarding differences in FA profiles of fish among habitat types in river-floodplain ecosystems. The objectives of this study were to 1) test whether the FA profiles of channel catfish (Ictalurus punctatus) differed among three reaches of the lower Kaskaskia River and its floodplain lakes, and 2) to compare FA profiles among muscle, liver, and adipose fin tissues collected from these fish. Profiles differed significantly among sites, especially between upper and lower river sites, and between river channel and oxbow lake sites, suggesting differences in FA availability for channel catfish occupying different habitats and river reaches in the Kaskaskia River system. Specifically, the essential FAs 18:2n-6 and 18:3n-3 increased in catfish tissues from upstream to downstream reaches, which could reflect increased floodplain connectivity and decreasing impoundment effects downstream. Ratios of n-3 to n-6 FAs were higher in fish from oxbow lakes, perhaps suggesting increased use of autochthonous production in the floodplain relative to the main river channel. Muscle and adipose fin FA profiles exhibited similar location-related trends, whereas liver FA profiles were markedly different from the other tissue types. These results suggest that adipose fin tissue samples may be a viable, less-invasive alternative to muscle tissue for analysis of FA profiles in channel catfish. Our study supports the use of tissue FA profiles in identifying habitat utilization by channel catfish, and perhaps habitat-specific energy contributions to riverine consumers. Furthermore, our work highlights floodplain habitat as a potential source of essential n-3 FA and the associated importance of maintaining river-floodplain connectivity to support aquatic food webs
Aboveground Net Primary Productivity in Grazed and Ungrazed pastures: Grazing Optimisation Hypothesis or Local Extinction of Vegetation Species
The controversy that has surrounded herbivory studies in the last few decades prompted our investigation to establish the extent to which herbivore optimisation hypothesis or compensatory growth evidence is real. We used the traditional movable cage method to collect primary productivity data on herbage, functional groups and key individual grass species in various controlled large herbivore treatments in an east African savanna. The herbivore treatments in triplicate blocks included cattle, wild herbivores with and without mega herbivores and combinations of cattle and wild herbivores also with and without mega herbivores. The findings revealed that at herbage level, most grazed treatments (four out of five) had higher productivity than the ungrazed control and three showed grazing optimisation curve at sixth polynomial degree between monthly productivity and grazing intensity (1-g/ng). At functional group level forbs productivity was higher in the ungrazed control than in any of the grazed treatments while at individual grass species level _Themeda triandra_ productivity was higher in all grazed treatments than in ungrazed control. We conclude against presence of herbivore optimisation hypothesis at herbage, functional group and species level because of lack of attributable grazing effect in grazed treatments that matches complex ecological effects in the ungrazed treatment
- …