4,985 research outputs found

    CONSUMER PREFERENCE AND DEMAND FOR ORGANIC FOOD: EVIDENCE FROM A VERMONT SURVEY

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    While organic farming has been identified as an effective way to improve food safety and environment quality, the adoption of organic production and processing is highly determined by the market demand for organic food products. To assess the market potential for organic apples and milk, a conjoint analysis is conducted in the state of Vermont to examine consumer evaluation of major product attributes and their tradeoffs. Results suggest that there is likely a significant niche market for organic apples and milk and many consumers, especially people who have purchased organic food products, are willing to pay more for organic apples and milk produced locally and certified by NOFA.Environmental Economics and Policy, Food Consumption/Nutrition/Food Safety,

    Ternary Inorganic Electrides with Mixed Bonding

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    A high-throughput screening based on first-principles calculations was performed to search for new ternary inorganic electrides. From the available materials database, we identified three new thermodynamically stable materials (Li12Mg3Si4, NaBa2O, and Ca5Ga2N4) as potential electrides made by main group elements, in addition to the well known mayenite based electride (C12A7:e−). Different from those conventional inorganic electrides in which the excess electrons play only the role of anions, the three new materials, resembling the electrides found in simple metals under high pressure, possess mixed ionic and metallic bonding. The interplay between two competing mechanisms, together with the different crystal packing motifs, gives rise to a variety of geometries in anionic electrons and rich physical phenomena such as ferromagnetism, superconductivity, and metal-insulator transition. Our finding here bridges the gap between electrides found at ambient and high-pressure conditions

    Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress.

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    The research reported herein studied the permeability of concrete containing recycled-concrete aggregate (RA), superfine phosphorous slag (PHS), and ground granulated blast-furnace slag (GGBS) with and without stress. Test results showed that the chloride diffusion coefficient of RA concrete (RAC) without external loads decreased with time, and the permeability of RAC is much lower than that of the reference concrete due to the on-going hydration and the pozzolanic reaction provided by the PHS and GGBS additives in the RAC mixture. The permeability of chloride under flexural load is much more sensitive than that under compressive load due to the differences in porosity and cracking pattern. At low compressive stress levels, the permeability of chloride decreased by the closing of pores and microcracks within RAC specimens. However, in a relatively short time the chloride diffusion coefficient and the chloride content increased rapidly with the increase of compressive stress when it exceeded a threshold stress level of approximate 35% of the ultimate compressive strength. Under flexural stress, the chloride transport capability increased with the increase of stress level and time. At high compressive and flexural stress levels, creep had a significant effect on the permeability of chloride in the RAC specimens due to the damage from the nucleation and propagation of microcracks over time. It is apparent that mortar cracking has more of a significant effect on the chloride transport in concrete than cracking in the interfacial transition zone (ITZ)
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