9,007 research outputs found

    The water footprint of olives and olive oil in Spain

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    This paper evaluates the water footprint of Spanish olives and olive oil over the period 1997-2008. In particular, it analyses the three colour components of the water footprint: green (rainwater stored in the soil), blue (surface and groundwater) and grey (freshwater required to assimilate load of pollutants). Apparent water productivity and virtual water embedded in olive oil exports have also been studied. Results show more than 99.5% of the water footprint of one liter of bottled olive oil is related to the olive production, whereas less than 0.5% is due to the other components such as bottle, cap and label. Over the studied period, the green water footprint in absolute terms of Spanish olive oil production represents about 72% in rainfed systems and just 12% in irrigated olive orchards. Blue and grey water footprints represent 6% and 10% of the national water footprint, respectively. It is shown that olive production is concentrated in regions with the smallest water footprint per unit of product. However, the increase of groundwater consumption in the main olive producing region (Andalusia), from 98 to 378 Mm3 between 1997 and 2008, has added significant pressure in the upstream Guadalquivir basin. This raises questions about the sustainability of irrigated olive orchards for export from the region. Finally, the virtual water related to olive oil exports illustrate the importance of green water footprint of rainfed olives amounting to about 77% of the total virtual water exports

    Hypothesis Testing in Predictive Regressions

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    We propose a new hypothesis testing method for multi-predictor regressions with finite samples, where the dependent variable is regressed on lagged variables that are autoregressive. It is based on the augmented regressiom method (ARM; Amihud and Hurvich (2004)), which produces reduced-bias coefficients and is easy to implement. The method's usefulness is demonstrated by simulations and by an empirical example, where stock returns are predicted by dividend yield and by bond yield spread. For single-predictor regressions, we show that the ARM outperforms bootstrapping and that the ARM performs better than Lewellen's (2003) method in many situations.Augmented Regression Method (ARM); Bootstrapping; Hypothesis Testing

    The effect of solution heat treatment on the tensile and creep properties of MarM-002

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    The nickel-base superalloy MarM-002 is a high strength precipitation hardening material used in structural applications in the gas turbine field. The microstructure of MarM-002 consists of fine y' precipitates, a y matrix, carbides and a eutectic y- y' where the y' can be composed of coarse lamellae or blocky y' precipitates. Increasing the volume fraction of fine y' by dissolving the coarse eutectic y' during solution treatment can raise the alloy strength. In practice the solution heat treatment temperature does not usually exceed 1220°C because of the danger of incipient melting. At 1220°c the eutectic y' does not dissolve and persists in the alloy structure. In the current project an alternative solution treatment technique, the varied rate solution heat treatment (VRSHT), was determined specifically for MarM-002, and was used to achieve higher solution treatment temperatures up to 1260°C without incipient melting. The microstructural response of MarM-002 to the conventional 1220°C solution heat treatment, and to solution treatment at temperatures above 1220°C, was studied extensively. Microstructural features such as carbide decomposition and the degree of y' and eutectic y' dissolution were noted. The tantalum and titanium rich carbides which form during casting were seen to decompose during solution treatment, while hafnium rich carbides precipitated in the interdendritic regions during heat treatment. The y' solvus and eutectic y' solvus was measured to be1260°C and 1280°C respectively. A 1050°C/12h +_ 870°C/16h ageing heat treatment was applied to the alloy following solution treatment and the effect on the y' characteristics was also studied

    School Marm\u27s Cat

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    ADAPTATION OF MEDITERRANEAN CROPS TO WATER PRESSURE IN THE EBRO BASIN: A WATER EFFICIENCY INDEX

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    In this paper, we assess the output-oriented technical efficiency of agricultural production functions in order to compare, over time, economic and environmental production processes in the different regions of the Spanish Ebro basin, in a climate change context. The measurement of technical efficiency in agriculture can provide useful information about the competitiveness of farms and their potential to increase its productivity moreover can help in the crops adaptation to water pressure by improving the management of scarce resources. Here, we generate an agricultural water efficiency index to evaluate the adaptation of some Mediterranean crops to the water pressures in this area. We estimate frontier production functions and technical efficiency measures, using panel data models. This will allow us to observe changes in production due to individual specific effects and those that are time specific. To characterize our model, we use historical data, about crop yields, water requirements and climate as well as socio-economic and geographical aspects of the most representative crops in the provinces of the Ebro basin during 1976-2007. Then we generate a ranking of the most efficient crops across geographical areas, given their water use and other inputs, to evaluate policy scenarios with adjustments in water supply.water efficiency index in agriculture, Ebro basin, climate change adaptation, Crop Production/Industries, Resource /Energy Economics and Policy,

    Historical development of the number concept

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    Thesis (M.A.)--University of Kansas, Mathematics, 1918. ; Includes bibliographical references

    Dynamics of banking technology adoption: an application to internet banking

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    This paper is concerned with examining behaviour of firms (banks) and consumers (banks’ customers) in the event of a new technology (internet banking) introduction. The determinants of consumer adoption of internet banking are characterised using survey data from Korea in both static and dynamic framework. I find evidence that adoption of internet banking is influenced by sex, age, marital status, degree of exposure to internet banking, and the characteristics of the banks. A duration analysis shows no evidence of first mover advantage (order effects) in internet banking whilst the largest bank (rank effects) in commercial banking remains dominant in internet banking. The results imply that the internet banking adoption is dominated by social norm effects

    Preliminary Investigations of Joining Technologies for Attaching Refractory Metals to Ni-Based Superalloys

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    In this study, a range of joining technologies has been investigated for creating attachments between refractory metal and Ni-based superalloys. Refractory materials of interest include Mo-47%Re, T-111, and Ta-10%W. The Ni-based superalloys include Hastelloy X and MarM 247. During joining with conventional processes, these materials have potential for a range of solidification and intermetallic formation-related defects. For this study, three non-conventional joining technologies were evaluated. These included inertia welding, electro-spark deposition (ESD) welding, and magnetic pulse welding (MPW). The developed inertia welding practice closely paralleled that typically used for the refractory metals alloys. Metallographic investigations showed that forging during inertia welding occurred predominantly on the nickel base alloy side. It was also noted that at least some degree of forging on the refractory metal side of the joint was necessary to achieve consistent bonding. Both refractory metals were readily weldable to the Hastelloy X material. When bonding to the MarM 247, results were inconsistent. This was related to the higher forging temperatures of the MarM 247, and subsequent reduced deformation on that material during welding. ESD trials using a Hastelloy X filler were successful for all material combinations. ESD places down very thin (5- to 10- m) layers per pass, and interactions between the substrates and the fill were limited (at most) to that layer. For the refractory metals, the fill only appeared to wet the surface, with minimal dilution effects. Microstructures of the deposits showed high weld metal integrity with maximum porosity on the order of a few percent. Some limited success was also obtained with MPW. In these trials, only the T-111 tubes were used. Joints were possible for the T-111 tube to the Hastelloy X bar stock, but the stiffness of the tube (resisting collapse) necessitated the use of very high power levels. These power levels resulted in damage to the equipment (concentrator) during welding. It is of note that the joint made showed the typical wavy bond microstructure associated with magnetic pulse/explosion bond joints. Joints were not possible between the T-111 tube and the MarM 247 bar stock. In this case, the MarM 247 shattered before sufficient impact forces could be developed for bonding
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