EFFECTIVE COSTS AND CHEMICAL USE IN U.S. AGRICULTURAL PRODUCTION: BENEFITS AND COSTS OF USING THE ENVIRONMENT AS A "FREE" INPUT

This study uses a cost-function-based model of production processes in U.S. agriculture to represent producers' input and output decisions, and the implied costs of reductions in risk associated with leaching and runoff from agricultural chemical use. The model facilitates evaluation of the statistical significance of measured shadow values for "bad" outputs, and their input- and output-specific components, with a focus on the impacts on pesticide demand and its quality and quantity aspects. The shadow values of risk reduction are statistically significant, and imply increased demand for effective pesticides over time that stem largely from improvements in quality due to embodied technology, and that vary substantively by region.Environmental Economics and Policy, Farm Management,

Laboratory characterization of brick walls rendered with a pervious lime-cement mortar

A laboratory study investigating important thermal retrofitting solutions for simple and double (cavity) brick walls is presented. Test walls were modified using materials of current interest including an external pervious lime-cement mortar render and insulation board prior to evaluation. Laboratory simulations of steady-state winter and summer scenarios were performed using apparatus comprising two opposing climate chambers. Temperature, relative humidity and heat flux rate were monitored with surface sensors every 10 min until stabilization on each wall type, retrofitting solution and climate scenario. The temperature and relative humidity profiles, heat flux, surface temperature difference, thermal conductance, condensation risk and stabilization times were assessed. Comparisons between simple and double (cavity) brick walls showed significant differences and a high condensation risk in the non-ventilated air cavity of the double wall. The pervious lime-cement mortar render enhanced substantially the thermal performance of the single wall although increased the condensation risk of the double (cavity) wall. As expected, the insulation layer reduced the thermal conductance of the wall, although the improvement in a summer scenario was considerably lower than in winter. The different performance observed between winter and summer steady-state conditions emphasized the importance of the heat and mass transfer coupling effect. Therefore, this work proves that effective retrofitting depends on materials, wall layouts and climate conditions. These experimental results provide essential knowledge about assessing the effects of common retrofitting solutions especially under hot-dry summer scenarios.</p

Fitting Parton Distribution Data with Multiplicative Normalization Uncertainties

We consider the generic problem of performing a global fit to many independent data sets each with a different overall multiplicative normalization uncertainty. We show that the methods in common use to treat multiplicative uncertainties lead to systematic biases. We develop a method which is unbiased, based on a self--consistent iterative procedure. We demonstrate the use of this method by applying it to the determination of parton distribution functions with the NNPDF methodology, which uses a Monte Carlo method for uncertainty estimation.Comment: 33 pages, 5 figures: published versio

Effect of deoxycholic acid on the performance of liquid electrolyte dye-sensitized solar cells using a perylene monoimide derivative

The effect of coadsorption with deoxycholic acid (DCA) on the performance of dye-sensitized solar cell based on perylene monoimide derivative (PCA) as sensitizer and liquid electrolyte had been investigated. The current-voltage characteristics under illumination and incident photon to current efficiency (IPCE) spectra of the DSSCs showed that the coadsorption of DCA with the PCA dye results in a significant improvement in short circuit photocurrent and slight increase in the open circuit photovoltage, which lead to an overall power conversion efficiency. The enhancement of short circuit current was attributed to the increased electron injection efficiency from the excited state of PCA into the conduction band of TiO2 and charge collection efficiency. The current-voltage characteristics in dark indicates a positive shift in the conduction which also supports the enhancement in the photocurrent. The coadsorption with DCA suppressed charge recombination as indicated from the electrochemical impedance spectra and thus improved the open circuit photovoltage

An updated analysis of NN elastic scattering data to 1.6 GeV

An energy-dependent and set of single-energy partial-wave analyses of $NN$ elastic scattering data have been completed. The fit to 1.6~GeV has been supplemented with a low-energy analysis to 400 MeV. Using the low-energy fit, we study the sensitivity of our analysis to the choice of $\pi NN$ coupling constant. We also comment on the possibility of fitting $np$ data alone. These results are compared with those found in the recent Nijmegen analyses. (Figures may be obtained from the authors upon request.)Comment: 17 pages of text, VPI-CAPS-7/

The application of electrical resistance measurements to water transport in lime–masonry systems

The paper describes an experimental determination of impedance spectroscopy derived resistance measurements to record water transport in lime–masonry systems. It strongly supports the use of Sharp Front theory and Boltzmann’s distribution law of statistical thermodynamics to corroborate the data obtained. A novel approach is presented for the application of impedance measurements to the water transport between freshly mixed mortars and clay brick substrates. Once placed, fresh mortar is dewatered by brick and during this time the volume fraction water content of the mortar is reduced. An equation is derived relating this change in water content to the bulk resistance of the mortar. Experimental measurements on hydraulic lime mortars placed in contact with brick prisms confirm the theoretical predictions. Further, the results indicate the time at which dewatering of a mortar bed of given depth is completed. The technique has then potential to be applied for in situ monitoring of dewatering as a means of giving insight into the associated changes in mechanical and chemical properties