A mechanical behavior law for the numerical simulation of the mushy zone in welding

The aim of this work is to propose a mechanical behavior law dedicated to the mushy zone located between the solid phase and the weld pool in welding. The objective is to take into account of the influence of the mushy zone in the simulation of welding in order to improve the computation of induced effects such as residual stresses

Buyer and Seller Response to an Adverse Food Safety Event: The Case of Frozen Salmon in Alberta

Fish is a low-fat protein source high in omega-3 fatty acids, but in 2004 consumers also heard that farmed salmon had high levels of polychlorinated biphenyl (PCBs). This research evaluated how Canadian consumers and processors reacted to the conflicting health messages. Demand estimates and time-series analysis of 2001-2006 frozen meat scanner data in Alberta, Canada show a significant drop in salmon expenditure share following the PCB finding. The industry responded by launching low-priced wild salmon products, which contributed to significant demand expansion. The analysis illustrates how a food safety threat was averted and even served as a catalyst for growth.Salmon, Scanner data, Food Safety, Demand, Directed acyclic graphs, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, D12, L15, Q11,

Spectrum sensing by cognitive radios at very low SNR

Spectrum sensing is one of the enabling functionalities for cognitive radio (CR) systems to operate in the spectrum white space. To protect the primary incumbent users from interference, the CR is required to detect incumbent signals at very low signal-to-noise ratio (SNR). In this paper, we present a spectrum sensing technique based on correlating spectra for detection of television (TV) broadcasting signals. The basic strategy is to correlate the periodogram of the received signal with the a priori known spectral features of the primary signal. We show that according to the Neyman-Pearson criterion, this spectral correlation-based sensing technique is asymptotically optimal at very low SNR and with a large sensing time. From the system design perspective, we analyze the effect of the spectral features on the spectrum sensing performance. Through the optimization analysis, we obtain useful insights on how to choose effective spectral features to achieve reliable sensing. Simulation results show that the proposed sensing technique can reliably detect analog and digital TV signals at SNR as low as -20 dB.Comment: IEEE Global Communications Conference 200

Buyer and Seller Responses to an Adverse Food Safety Event: The Case of Frozen Salmon in Alberta

Fish is a low-fat protein source high in omega-3 fatty acids, but in 2004 consumers also heard that farmed salmon had high levels of polychlorinated biphenyl (PCBs). This research evaluated how Canadian consumers and processors reacted to the conflicting health messages. Demand estimates and time-series analysis of 2001-2006 frozen meat scanner data in Alberta, Canada show a significant drop in salmon expenditure share following the PCB finding. The industry responded by launching low-priced wild salmon products, which contributed to significant demand expansion. The analysis illustrates how a food safety threat was averted and even served as a catalyst for growth.salmon, scanner data, food safety, demand, directed acyclic graphs, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Research Methods/ Statistical Methods, Q10, Q11, Q16, Q22,

The Effects of E. Coli 0157:H7, FMD and BSE on Japanese Retail Beef Prices: A Historical Decomposition

This study examines the time-varying Japanese price reactions to the 2001 Bovine Spongiform Encephalopathy (BSE) discovery, the 2000 outbreak of foot and mouth disease (FMD), and the 1996 E. coli food po isoning events. Historical decomposition of retail-level price-series aids in explaining the behavior of beef prices in a neighborhood (period-by-period time interval) of the three events. This is based on an application of directed acyclic graphs, constructing orthogonal innovations to determine causal patterns behind contemporaneous innovations. The results show the beef safety events had different negative impacts on Japanese retail beef prices, suggesting that consumers understood and differentiated among the health risks. The results provide incentives for beef producers and retailers to proactively inform consumers about ongoing beef safety measures. Understanding consumer reaction to BSE, FMD and E. coli helps the beef industry restore consumer confidence after future food safety crises, and provides policy makers a basis for countermeasures and compensations.Japan, beef prices, BSE, FMD, E. coli, historical decomposition., Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Livestock Production/Industries, Q11, Q13,