Expansion dynamics of Lennard-Jones systems

The dynamics of the expansion of a Lennard-Jones system, initially confined at high density and subsequently expanding freely in the vacuum, is confronted to an expanding statistical ensemble, derived in the diluted quasi-ideal Boltzmann approximation. The description proves to be fairly accurate at predicting average one-body global observables, but important deviations are observed in the configuration-space structure of the events. Possible implications for finite expanding physical systems are outlined

Innovation, low energy buildings and intermediaries in Europe: systematic case study review

As buildings throughout their lifecycle account for circa 40% of total energy use in Europe, reducing energy use of the building stock is a key task. This task is, however, complicated by a range of factors, including slow renewal and renovation rates of buildings, multiple non- coordinated actors, conservative building practices, and limited competence to innovate. Drawing from academic literature published during 2005-2015, this article carries out a systematic review of case studies on low energy innovations in the European residential building sector, analysing their drivers. Specific attention is paid to intermediary actors in facilitating innovation processes and creating new opportunities. The study finds that qualitative case study literature on low energy building innovation has been limited, particularly regarding the existing building stock. Environmental concerns, EU, national and local policies have been the key drivers; financial, knowledge and social sustainability and equity drivers have been of modest importance; while design, health and comfort, and market drivers have played a minor role. Intermediary organisations and individuals have been important through five processes: (1) facilitating individual building projects, (2) creating niche markets, (3) implementing new practices in social housing stock, (4) supporting new business model creation, and (5) facilitating building use post construction. The intermediaries have included both public and private actors, while local authority agents have acted as intermediaries in several cases

Systemtheorie der Photonik Abschlussbericht

This study of the systems theory of photonics was dedicated to a top-down investigation of the chances of photonics as regards conductive connections. The results were presented during a special meeting and a course of lectures. The contributions submitted by the Institute of Physics of the University of Erlangen deal with spatial photonics, temporal photonics, optical 3d wiring in free space, new algorithms (fractional Fourier transforms), and with the fundamental limits. It was found that, generally, the maximum clock-pulse rate and the degree of parallelism are coupled. The systems theory approach was also applied to the promotion strategy which the Federal Ministry of Research and Technology uses especially in the field of photonics. (orig.)SIGLEAvailable from TIB Hannover: D.Dt.F.QN1(17,32) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Microstructure and fracture mechanism investigation of porous silicon nitride zirconia graphene composite using multi scale and in situ microscopy

Silicon nitride zirconia graphene composites with high graphene content 5 wt. and 30 wt. were sintered by gas pressure sintering GPS . The effect of the multilayer graphene MLG content on microstructure and fracture mechanism is investigated by multi scale and in situ microscopy. Multi scale microscopy confirms that the phases disperse evenly in the microstructure without obvious agglomeration. The MLG flakes well dispersed between ceramic matrix grains slow down the phase transformation from amp; 945; to amp; 946; Si3N4, subsequent needle like growth of amp; 946; Si3N4 rods and the densification due to the reduction in sintering additives particularly in the case with 30 wt. MLG. The size distribution of Si3N4 phase shifts towards a larger size range with the increase in graphene content from 5 to 30 wt. , while a higher graphene content 30 wt. hinders the growth of the ZrO2 phase. The composite with 30 wt. MLG has a porosity of 47 , the one with 5 wt. exhibits a porosity of approximately 30 . Both Si3N4 MLG composites show potential resistance to contact or indentation damage. Crack initiation and propagation, densification of the porous microstructure, and shift of ceramic phases are observed using in situ transmission electron microscopy. The crack propagates through the ceramic MLG interface and through both the ceramic and the non ceramic components in the composite with low graphene content. However, the crack prefers to bypass ceramic phases in the composite with 30 wt. ML

Isotope effects in the metastable decay of Ne

Neon dimer ions undergo spontaneous dissociation (metastable decay) several microseconds after formation by electron impact ionization of neon clusters. In this contribution we compare the kinetic energy release distribution (KERD) of the previously reported isotopomer 20Ne2+ with that of 22Ne2+. The heavy isotopomer shows the same two components in the KERD as the lighter ones. However, the high-energy component that is due to electronic pre-dissociation is reduced in intensity. The decrease is attributed to a reduced predissociation rate from the II(1/2u) state into I(3/2u)