Experimental Investigation of the Natural and Forced Convection on Solidification of Sn-3wt.%Pb Alloy Using a Benchmark Experiment

We deal with the development of a solidification benchmark experiment in order to investigate the structure formation as well as solute macro-mesosegregation,by means of a well-controlled solidification experiment.The experiment consists in solidifying a rectangular ingot of Sn-3wt.%Pb alloy,by using two lateral heat exchangers which allow extraction of the heat flux from one or two vertical sides of the sample.The domain is a quasi two dimensional parallepipedic ingot(100×60×10)mm.The temperature difference AT between the two lateral sides is 40 K and the cooling rate CR=0.03 K/s.The instrumentation consists in recording the instantaneous temperature maps by means of an array of 50 thermocouples in order to provide the time evolution of the isotherms.After each experiment the patterns of the segregations have been obtained by X-ray radiograph and confirmed by eutectic fraction measurements.The local solute distribution determined by means of induction coupled plasma analysis is provided.The originality of the present study is to examine the effect of the forced convection driven by a travelling magnetic field(TMF)induced by a linear inductor located on the bottom part of the sample.A periodically reversed stirring with a modulation frequency equal to 0.5 Hz stirring have been investigated.This study allows us to evaluate the evolution due to the forced convection induced by a TMF field,as well as its influence on the initial conditions,the solidification macrostructure and the segregation behavior.Measurements of the velocity field by ultrasonic Doppler velocimetry(UDV)method in a Ga-In-Sn pool were performed and transposed to the tin-lead alloy case before solidification.Post-mortem patterns of the macromesosegregations have been obtained by X-ray radiography.The results show the transport effects of the flow on both the maerosegregations and the channel formation.The reversal of the TMF produces a decrease of the level of mesosegregations,namely channel formation.

The Relationship between Firm-Specific Return Variation and Price Informativeness:Some Cross-Sectional Evidence

The progressive removal of short-selling constraints in the Chinese stock market provides us with a natural experiment to investigate the relationship between firm-specific return variation(FSRV)and price informativeness.Based on the empirical finding that idiosyncratic volatility is a satisfied proxy for FSRV when the information environment for individual firms improves,we mainly find that the FSRV is negatively related to price informativeness.This negative relationship is robust to alternative model specifications,alternative proxies for price informativeness,and alternative estimation windows.Generally speaking,our results complement the extant literature on the mixed relationships between FSRV and price informativeness by providing cross-sectional evidence.

Nature experience promotes preference for and willingness to coexist with wild animals among urban and suburban residents in Malaysia

Introduction:A decline in direct experience with nature can lead to disaffection of natural environments,wildlife,and public indifference towards biodiversity conservation.This study measured on affective attitude towards wildlife(i.e.,preferences for and willingness to coexist with 22 animal species)and examined the relationships between these attitudes and childhood experiences with nature.Methods:A face to face interview was carried out in rapidly urbanizing Malaysia for both urban and suburban 357 adults(age>20 years old).Results:It found that Malaysian people liked several insects and squirrels,but disliked mammals generally.Mediation analysis,with controlling sociodemographic factors(gender,age and ethnicity),showed that childhood nature experience was positively associated with preference for wild animals(standardized path coefficient=0.18;p<0.001),and the preference had a strong correlation with willingness to coexistence(standardized path coefficient=0.61;p<0.001)with the animals.Childhood nature experience,however,had limited effects on willingness to coexist with the animals via the preference,particularly for unfavourable animals.These results suggest that preference and willingness scores,even though they were significantly correlated,were different sides of affective attitudes toward animals.Conclusions:Therefore,to promote biodiversity conservation programs,we need strategies to increase acceptance of wild animals via relevant environmental education and public communication,as well as opportunities for nature activities for children.