The simulation for damage of metal powder compacts during forming
The main models of describe metal powder compacting are introduced in this paper. Based on a new model derived from Lee's metal powder compacting model and plastic theory for porous material, the scent of damage status of two-level flanged metal powder compacts during forming is simulated and the damage state and cracking process of compacts in different load process are followed up.
A CRITERION OF DUCTILE DAMAGE IN METALFORMING
Based on Lemaitre's four basic elements, such as damage variable, hypothesis of isotropy, concept of effective stress and hypothesis of strain equivalence, and thermodynamics as well, and also on the author's hypothesis that damage can only be developed on plastic deformation with tensile stress, a new model of isotropic ductile damage was derived. The new model can explain that on the free surface of free homogeneous upsetting there is no ductile fracture.
Conflictual Media Events, Eyewitness Images, and the Boston Marathon Bombing (2013)
The proliferation of camera phones over the past decade has created an unprecedented landslide of visual information in the online public sphere, transforming the form and amount of communication in relation to crisis events. International research on this subject has primarily centered on the way in which the production and dissemination of eyewitness images convert mainstream media's coverage of crisis. This article broadens the perspective by focusing on eyewitness images in relation to “conflictual media events.” The article contributes to discussions on the definition of conflictual media events in today's mediatized and connective media environment, which has undergone radical changes from the era of mass media hegemony when Daniel Dayan and Elihu Katz first outlined media events. The article further examines the ways in which the circulation of eyewitness images erodes established boundaries between experts and laymen and between professionals and non-professionals in relation to conflictual media events. The bombing of the Boston Marathon in April 2013 constitutes the empirical point of departure.