2,442 research outputs found
What makes countries initiate WTO disputes on food-related issues?
This paper analyses relevant determinants for the probability to initiate a dispute on policy measures under the World Trade Organization (WTO) dispute settlement system. The empirical analysis differs from existing assessments by focusing on agri-food related disputes and provides a more in-depth analysis of specific country and sectoral characteristics not considered in previous studies. Contrary to recent analyses of overall trade disputes, the results show that some determinants such as legal capacity and monetary means are not statistically significant. Own protectionist behaviour, endured protectionism, and the duration of WTO membership, however, could be identified as relevant determinants with the expected direction of impact.WTO dispute, agri-food sector, binary choice model, International Relations/Trade,
INFLUENCES OF THE GOVERNMENTAL MARKET INTERVENTIONS ON WHEAT MARKETS IN SERBIA DURING THE FOOD CRISIS 2007/2008
This paper analyzes how the market interventions of the Serbian government during the food crisis 2007/2008, inter alia a de facto export ban, have affected domestic wheat markets. Besides a comprehensive description of the crisis policy and its effects on the Serbian wheat market, we investigate how it influences the equilibrium and stability of the Serbian wheat market and its integration with the world market within a price transmission model. Applying a Markov-switching error correction model to weekly wheat grower prices in Serbia and world market prices, two states of the wheat market are identified. Our results suggest that although the long-run price elasticity did not change during the crisis, the market equilibrium was disrupted and the market stability reduced. Also, we find that the price dampening effect of the export restrictions was only short-lived, and that Serbian wheat grower prices even increased above the world market level.international market integration, Markov-Switching Error Correction Model, Serbia, wheat market, world market price transmission, Agricultural and Food Policy, Crop Production/Industries, C34, Q11, Q13, Q17, Q18,
What makes countries initiate WTO disputes on food-related issues?
This paper analyses relevant determinants for the probability to initiate a dispute on policy measures under the World Trade Organization (WTO) dispute settlement system. The empirical analysis differs from existing assessments by focusing on agri-food related disputes and provides a more in-depth analysis of specific country and sectoral characteristics not considered in previous studies. Contrary to recent analyses of overall trade disputes, the results show that some determinants such as legal capacity and monetary means are not statistically significant. Own protectionist behaviour, endured protectionism, and the duration of WTO membership, however, could be identified as relevant determinants with the expected direction of impact.WTO dispute, agri-food sector, binary choice model, International Relations/Trade, C12, C13, F13,
HOW DID POLICY INTERVENTIONS IN WHEAT EXPORT MARKETS IN RUSSIA AND UKRAINE DURING THE FOOD CRISIS 2007/2008 INFLUENCE WORLD MARKET PRICE TRANSMISSION?
International price transmission, wheat market, food crisis, Markov switching error correction model, Russia, Ukraine, Agricultural and Food Policy, Demand and Price Analysis, Research Methods/ Statistical Methods,
Impacts of Export Controls On Wheat Markets During the Food Crisis 2007/2008 in Russia and Ukraine
This paper investigates the impacts of export controls in Russia and Ukraine on wheat world market price transmission during the 2007/2008 global food crisis. Russia and Ukraine aimed to reduce wheat exports induced by extraordinarily high world market prices to secure sufficient wheat supply on the domestic markets. Utilizing a Markov-Switching vector error correction model (MSVECM), we find that the temporary export restrictions induced negative effects on wheat markets in Russia and Ukraine. Although instability increased on the world markets itself, we have shown that the increase in the market instability was particularly pronounced in Russia and Ukraine. Also, the export restrictions dampened price transmission to the farmers’ prices, which pushed the growers’ prices below their long-run equilibrium level. Thus, investment incentives in wheat production which could result from high world market prices were foregone.International price transmission, wheat market, food crisis, Markov switching error correction model, Russia, Ukraine, Demand and Price Analysis, International Relations/Trade,
Fluorine Containing UV-Curable Materials for Advanced Transport Applications
The characterization of structure, thermal, gas transport, and free volume properties of two unique UV cured polymeric systems are studied and reported. In the initial pursuit of waterproof high water vapor transport membranes, it became apparent that the UV curing of fluorinated materials yielded routes to develop unique materials that fundamentally challenge conventional models for free volume and light gas transport behavior. UV-curing provides a means to rapidly “lock-in” morphologies that are accessible in the small molecule, monomer phase but rapidly become kinetically inaccessible when constraints such as covalent bonding and cross linking limit motion in the polymer system. This “locking-in” was exploited in Chapters II, III, IV, and V while Chapters VI and VII study this phenomenon.
While the motivation for this project stems from the ability to selectively transport water vapor over bulk water, similar principals are used in the selective transport of light gases. Light gases were extensively used in this work to probe the molecular structures of high permeability polymer networks. Probing of these molecular structures was supported by extensive free volume analysis using both volumetric and molecular probing of free volume properties.
The first chapter of this document outlines the basics of fluorinated, UV cured and thiol-ene materials, transport of gases in polymeric systems, and free volume. These topics are complimented by a discussion of the methods used throughout this work to study the phenomena described.
Chapter II gives brief overview of our research group’s historical modification of thiol-ene networks. Through the modification of a tetrafunctional thiol with various chemical moieties, our group has shown the ability to retain the glass transition temperature of a network while tuning the permeability of the system over three orders of magnitude through the use of hydrogen bonding groups, linear aliphatic, and linear perfluorinated modifications. UV-curing allows for the rapid development of a network where monomer functionality was retained, leading to networks with similar long range connectivity and short range differences in backbone spacing and free volume. Chapter III continues this work by exploring the modification of thiol-ene networks with silane groups. Chapter IV delves into the details of the modification procedure using perfluorinated acrylate moieties as the modification. By changing the length of linear perfluorinated acrylates bound covalently into the network, the repulsion of the network backbone by the fluorinated moiety increases. This phenomenon was evidenced by free volume, X-ray diffraction, DSC and pressure volume temperature data and analysis. The resulting “thermodynamic frustration,” caused by the incompatible fluorinated groups, increased the transport of light gases across 2.5 orders of magnitude in some cases and shows a stretching of the network backbone structure without impacting glass transition temperature.
Chapters VI and VII highlight the exploration of “switchable” fluorinated UV-cured acrylate side chain polymers. The rigid rod structure of side chain acrylates of a given length gives rise to a morphology that has a well-defined crystalline order and melting temperature. Melting of this ordered structure gives rise the “switching” behavior that can be utilized as a molecular valve for certain applications, activated using a thermal stimulus. The well-defined order of C8F17 -and C10F21 side chain acrylates was well characterized and shown to develop a mesophase upon UV-curing that was irreversible unless quenched using liquid nitrogen. The well-defined melting temperature of 72 °C was exploited in the study of gas transport properties that traversed this melting temperature, showcasing the permeability switching. Permeability gains across the melting of the ordered morphology, for several gases, were shown to be due to solubility increases alone. Contrary to standard two-phase systems where ordered phases increase tortuosity and therefore decrease diffusivity in the semicrystalline systems, these systems show no discernable switch in diffusivity across the transition temperature. Analysis of both the free volume hole size and volume contributions are reported. Furthermore, the side chain morphology lends itself to high He/H2 separation performance
Shot Peening Method for Aerofoil Treatment of Blisk Assemblies
AbstractAdvanced compressor designs today often include blade integrated disc (blisk) rotors, with high demands on aerodynamic performance, resistance againsthigh load levels and foreign object damage (FOD).To increasethe highcycle fatigue (HCF) strength, compressive residual stresses are introduced into the surface and subsurface layer of aerofoil, fillet (transient area between aerofoil and disk) and annulus (intermediate area between aerofoils). For generatingcompressive residual stresses several different industrial production processes are used, beside ultrasonic shot peening, laser shock peening, deep rolling and shot peening wet and dry with glass or ceramic media is shot peening with steel media the mostly used technology. However, depending on the size of the componentaccessibility for tools might be limited and the set-up of economical production techniques challenging for blisk shot peening.This paper gives an introduction into blisk shot peening, a sophisticated mechanical surface technology for treating aerofoil surfaces of blisk rotors using special designed calliper nozzles assolution for introducing uniform residual compressive stress states, as well as consistentshot peening coverage levels
What Students Think They Feel Differs from What They Really Feel - Academic Self-Concept Moderates the Discrepancy between Students\u27 Trait and State Emotional Self-Reports
This study investigated whether there is a discrepancy pertaining to trait and state academic emotions and whether self-concept of ability moderates this discrepancy. A total of 225 secondary school students from two different countries enrolled in grades 8 and 11 (German sample; n = 94) and grade 9 (Swiss sample; n = 131) participated. Students\u27 trait academic emotions of enjoyment, pride, anger, and anxiety in mathematics were assessed with a self-report questionnaire, whereas to assess their state academic emotions experience-sampling method was employed. The results revealed that students\u27 scores on the trait assessment of emotions were generally higher than their scores on the state assessment. Further, as expected, students academic self-concept in the domain of mathematics was shown to partly explain the discrepancy between scores on trait and state emotions. Our results indicate that there is a belief-driven discrepancy between what students think they feel (trait assessment) and what they really feel (state assessment). Implications with regard to the assessment of self-reported emotions in future studies and practical implications for the school context are discussed
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