Powder metallurgy influences on the magnetic properties of Gd5.09Ge2.03Si1.88 alloy

Magnetic refrigeration is an innovative technology owing to its high-efficiency, low-energy consumption, and environmental friendliness. However, the manufacturing process of the magnetocaloric materials is an obstacle to the effective application of those materials on refrigeration systems. In this work, we present a magnetic characterization of the Gd5.09Ge2.03Si1.88. alloy, analyzing the as-cast bulk and the sintered tablets after some heat treatments. The study of powder metallurgy parameters such as grain size, compacting pressure and sintering process has showed results comparable to the as-cast alloy, which presents Delta S-T = -18 /kg K. (c) 2008 Elsevier B.V. All rights reserved.32081582158

Participacija in vsebina nizozemskih strankarskih razpravljalskih skupin na Internetu

Članek obravnava dve politični razpravljalski skupini, povezani z nizozemskimastrankama D66 in GroenLinks, in njun prispevek k demokraciji. Razpravljanje naj bi bilo v demokraciji posvetovalno: temeljilo naj bi na racionalni argumentaciji, naj bi ne bilo podvrženo monopolu posameznikov, povezano naj bi bilo z javnimi zadevami. Članek proučuje posvetovalnost političnega razpravljanja na internetu, tako da meri prispevek posameznega udeleženca. Rezultati kažejo, da sta imeli obe listi le majhen delež zelo pogostih udeležencev. Prispevki razpravljavcev so bili usmerjeni k drugim razpravljavcem v skupini. Mnenja so bila običajno izražena brez argumentov, čepa so bili argumenti že izraženi, so bili zdravorazumski ali pa so izhajali iz časopisov ali teleteksta. Razpravljalna foruma nista upravičila pričakovanjglede pospeševanja demokracije. Lahko pa zapolnjujeta prostor med institucionaliziranim javnim razpravljanjem, ki poteka v strankarskih elitah, in neinstitucionaliziranim, neformalnim javnim razpravljanjem, ki izvira iz drugih javnih in zasebnih sfer.This study examines two political discussion lists affiliated with the Dutch political parties D66 and GroenLinks, and the possible contribution of these lists to democracy. Discussion in a democracy, it is argued, should be deliberative: based on rational argumentation, not monopolised by any particular individuals, and related to public affairs. The aim of this study is to assess the deliberativeness of political discussion lists on the Internet. To this end, the degree of contribution from participants to the lists is measured. The findings from this study suggest that, whereas the discussions on the lists as a whole were not monopolised by any individual, both lists had only a small number of very frequent participants. The contributions of members of this in-group were oriented towards one another. Opinions were mainly expressed without argumentation, and when argumentation was given it was predominantly based on common sense or on external sources such as newspapers or teletext. These two discussion lists do not live up to the expectations of furthering democracy. They may, however, eventually serve to fill the gap between the institutionalised public discussion that exists within the party elite and the uninstitutionalised, informal public discussion that transpires in other public and private domains