Land Quality and International Agricultural Productivity: A Distance Function Approach

Agricultural productivity measurement has been of great interest in recent years. Although analysts have long recognized that land quality plays an important role in agricultural productivity, land quality has been difficult to quantify and include in productivity models due to d ata limitations. Poor land quality, in the form of desertification, erosion, and poor soil quality, as well as climate and precipitation may limit growth in productivity over time. A Malmquist productivity index is proposed that decomposes productivity into efficiency change, technical change and land quality components and accounts for inter-country differences in land quality. The index is then applied to a 109-country data set covering 1980 to 2003. Many countries with lower productivity growth are limited by their resource endowment, and thus require policies and technology that reflect the needs of those environments.Land Economics/Use, Productivity Analysis,

RISK, GOVERNMENT PROGRAMS, AND THE ENVIRONMENT

Nearly all farm business ventures involve financial risk. In some instances, private and public tools used to manage financial risks in agriculture may influence farmers' production decisions. These decisions, in turn, can influence environmental quality. This bulletin summarizes research and provides some perspective on private and public attempts to cope with financial risks and their unintended environmental consequences. Specifically, it examines the conceptual underpinnings of risk-related research, challenges involved with measuring the consequences of risk for agricultural production decisions, government programs that influence the risk and return of farm businesses, and how production decisions influence both the environment and the risk and average returns to farming.risk, agricultural production, government programs, environment, Agricultural and Food Policy, Environmental Economics and Policy, Risk and Uncertainty,

Electrical Performance Retention of Doped Carbon Nanotube Conductors for High Current Applications

Carbon nanotube (CNT) wires are light-weight and robust alternatives to conventional metal conductors. The weight savings, increased flexure tolerance, and corrosion resistance of CNT conductors make them a viable solution for a variety of space, defense, and power transmission applications. An individual CNT has orders of magnitude greater electrical conductivity than conventional metal conductors, but this has not been realized in bulk CNT networks. Recently, the use of chemical dopants has resulted in bulk CNT wire conductivities approaching 10 MS/m. As the electrical conductivity of CNT wires continues to approach that of conventional metals, deployment of CNT conductors will require an understanding of how doped CNT conductors behave during practical operation. The initial dissertation research applied radial densification and KAuBr4 chemical doping to commercially available CNT wires resulting in a 6x improvement in electrical conductivity and 67% increase in failure current density. Novel procedures were developed to probe the electrical performance retention as a function of increasing and sustained current application. KAuBr4-densified CNT wires can withstand current densities up to 32 MA/m2 with no degradation in electrical conductivity, exceeding the as-received CNT material’s degradation threshold by greater than 3x. The improved electrical conductivity of KAuBr4-densified CNT wires prevents the onset of Joule heating allowing for the doping benefits to be maintained at increased applied current densities. Further analysis compared the resulting electrical performance retention of three commonly used chemical dopants: I2, IBr, and KAuBr4. The as-received and KAuBr4 doped CNT wires can maintain σRest until near wire failure, while the I2 and IBr doped CNT wires experience degradation at current densities greater than 5 MA/m2. With repeated low current cycling, KAuBr4 was identified as the only dopant able to maintain its initial electrical conductivity over time. Thermal stability analysis determined that I2 and IBr doped CNT wires undergo dopant desorption, while KAuBr4 doped CNT wires result in dopant degradation into other viable dopants, thus maintaining improved electrical conductivity over greater applied current densities. KAuBr4 doped CNT wires have emerged as lightweight conductors capable of retaining their improved electrical properties during long-term, high current applications. Thus, motivating the future adoption of stable KAuBr4 doped CNT wires in a variety of space and defense technologies

An alternate algorithm for correction of the scanning multichannel microwave radiometer polarization radiances using Nimbus-7 observed data

The manner in which Nimbus-7 scanning multichannel microwave radiometer (SMMR) scan radiance data was used to determine its operational characteristics is described. The predicted SMMR scan radiance was found to be in disagreement at all wavelengths with a large area of average measured ocean radiances. A modified model incorporating a different phase shift for each of the SMMR horizontal and vertical polarization channels was developed and found to provide good data correlation. Additional study is required to determine the validity and accuracy of this model

RESOURCE QUALITY AND AGRICULTURAL PRODUCTIVITY: A MULTI-COUNTRY COMPARISON

This paper builds on earlier studies of agricultural productivity by incorporating spatially referenced soil and climate data combined with high-resolution land-cover data. Econometric analysis of these data, along with panel data on agricultural inputs and outputs from 110 countries for 1961-1997, quantifies the significant impact that differences in land quality have on agricultural productivity.Productivity Analysis,

Guidelines for Safe Canning of Acid Foods in a Steam Canner

Steam canning, or atmospheric steam canning, can be a safe as well as energy efficient method for home preservation of most high-acid foods. This leaflet explains the differences between steam canners and boiling water canners and explains how to use a steam canner safely