Insulating effectiveness of self-spacing dimpled foil

Experimental data are graphed for determining conductive heat losses of multilayer insulation as function of number of foil layers. Foil was 0.0051 cm thick Nb, 1% Zr refractory alloy, dimpled to 0.0254 cm with approximately 28 dimples/sq cm. Heat losses were determined at 0.1 microtorr between 700 and 1089 K

On the Potential Use of Adaptive Control Methods for Improving Adaptive Natural Resource Management

The paradigm of adaptive natural resource management (AM), in which experiments are used to learn about uncertain aspects of natural systems, is gaining prominence as the preferred technique for administration of large-scale environmental projects. To date, however, tools consistent with economic theory have yet to be used to either evaluate AM strategies or improve decision-making in this framework. Adaptive control (AC) techniques provide such an opportunity. This paper demonstrates the conceptual link between AC methods, the alternative treatment of realized information during a planning horizon, and AM practices; shows how the different assumptions about the treatment of observational information can be represented through alternative dynamic programming model structures; and provides a means of valuing alternative treatments of information and augmenting traditional benefit-cost analysis through a decomposition of the value function. The AC approach has considerable potential to help managers prioritize experiments, plan AM programs, simulate potential AM paths, and justify decisions based on an objective valuation framework.adaptive control, adaptive management, dynamic programming, value of experimentation, value of information, Resource /Energy Economics and Policy,

Multi-Sector Sustainability in Agroecosystem Environments: Using Value Function Iteration for Numerical Solutions

Using the numerical technique of value iteration, this paper imposes several sustainability constraints on a simple multi-sector agroecosystem model, and provides analysis of the costs tradeoffs within and between generations. Results show that internalization of a stock externality is insufficient for intergenerationally equitable welfare paths, while sustaining a physical resource over time in the interests of equitability can result in a less equitable distribution of welfare across generations. Furthermore, a value sustainability constraint imposed on the social welfare maximization problem acts as a welfare transfer mechanism from the productive sector to the sector affected by the externality, but implies growth in profits for the productive sector and declining utility for the non-productive sector.Environmental Economics and Policy,

Consumer Preferences for Locally Made Specialty Food Products Across Northern New England

Does willingness to pay a premium for local specialty food products differ between consumers in Maine, New Hampshire, and Vermont? Two food categories are investigated: low-end ($5) and high-end ($20) products. Premia estimates are compared across states and across base prices within states using dichotomous choice contingent valuation methods. Results suggest that the three states of northern New England have many similarities, including comparable price premia for the lower-priced good. However, there is some evidence that the premium for the higher-priced good is greater for the pooled Vermont and Maine treatment than for the New Hampshire treatment. Vermont and New Hampshire residents are willing to pay a higher premium for a $20 than for a$5 food item, while the evidence suggests that Maine residents are not.local specialty foods, willingness to pay, contingent valuation, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety,

What to Choose? The Value of Label Claims to Produce Consumers

This paper addresses three key empirical questions related to health, nutrient, and process claims on front-label packaging; namely, 1) How do consumers value alternative claims on product and process-based attributes for fresh produce; 2) Are these values additively separable; and 3) To what degree is there heterogeneity between consumers on these values? We use a hypothetical choice experiment on red leaf lettuce attribute bundles, and estimate several logit models (MNL and ML) that provide estimates of marginal utilities (and with the inclusion of varying prices, marginal values) of various attributes related to general health claims, specific nutrition and health claims, certification logos related to health and nutrition currently found in the marketplace, as well as certified organic claims (relative to the conventional reference group). The results showed that consumers do distinguish between competing claims and logos, though the impacts are not always as expected, likely due to the information set used at the time of the choice. We found some evidence of attribute bundling between the health claims and the familiar Five-a-day program logo, and between organic production and a claim regarding vitamin C content. Finally, we found that use of the unconditional distributions (relative to the conditional)in a ML model overstates the degree of preference heterogeneity across the sample and overstates the magnitude of the marginal effects of the random parameters. This may create misleading impressions regarding the existence and size of specialized niche markets, the response of consumers to varying health, nutrition, or process claims, and/or the response of consumers to the introduction of new products with these (or similar) claims.Consumer/Household Economics, Demand and Price Analysis,

New safety model for the commercial human spaceflight industry

The aviation and space domains have safety guidelines and recommended practices for Design Organisations (DOs) and Operators alike. In terms of Aerospace DOs there are certification criteria to meet and to demonstrate compliance there are Advisory Circulars or Acceptable Means of Compliance to follow. Additionally there are guidelines such as Aerospace Recommended Practices (ARP), Military Standards (MIL-STD 882 series) and System Safety Handbooks to follow in order to identify and manage failure conditions. In terms of Operators there are FAA guidelines and a useful ARP that details many tools and techniques in understanding Operator Safety Risks. However there is currently no methodology for linking the DO and Operator safety efforts. In the space domain NASA have provided safety standards and guidelines to follow and also within Europe there are European Co-operation of Space Standardization (ECSS) to follow. Within the emerging Commercial Human Spaceflight Industry, the FAA’s Office of Commercial Space Transportation has provided hazard analysis guidelines. However all of these space domain safety documents are based on the existing aerospace methodology and once again, there is no link between the DO and Operator’s safety effort. This paper addresses the problematic issue and presents a coherent methodology of joining up the System Safety effort of the DOs to the Operator Safety Risk Management such that a ‘Total System’ approach is adopted. Part of the rationale is that the correct mitigation (control) can be applied within the correct place in the accident sequence. Also this contiguous approach ensures that the Operator is fully aware of the safety risks (at the accident level) and therefore has an appreciation of the Total System Risk. The authors of this paper contend that it is better practice to have a fully integrated safety model as opposed to disparate requirements or guidelines. Our methodology is firstly to review ‘best practice’ approaches from the aviation and space industries, and then to integrate these approaches into a contiguous safety model for the commercial human spaceflight industry

Direct Marketing of Fresh Produce: Understanding Consumer Purchasing Decisions

Consumer/Household Economics, Crop Production/Industries, Marketing, Q13,