Electron diffraction studies of supersonic jets. IV. Conformational cooling of n‐butane

Expansions through small tapered nozzles (∼10−2 cm inlet diameter) have produced conformational cooling of gas phase n‐butane to estimated conformational temperatures as low as 180 K. Relaxation into the lower energy trans form was seen with neat butane and with addition of up to ∼30% helium or neon. Thin plate nozzles of comparable diameter do not seem to produce the same effects, presumably because the more rapid cooling they bring about is accompanied by many fewer collisions. Conformational analyses carefully checked for and took into account butane cluster scattering, which if present and ignored, artificially increases the apparent trans mole fraction. At higher concentrations of monatomic carrier gas the cluster scattering becomes strong enough to interfere seriously with the determination of conformational composition. Analysis of the present data and a reanalysis of earlier, conventional, gas electron diffraction data both gave the room temperature trans mole fraction as 64% (3σ=9%) in agreement with a recent spectroscopic inference of 68%.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70828/2/JCPSA6-78-3-1270-1.pd

Electron diffraction studies of supersonic jets. III. Clusters of n‐butane

Expansions of n‐butane from small nozzles were observed to generate large clusters, provided that enough helium or neon carrier gas accompanied the butane to remove the heat of condensation rapidly and to produce low temperatures. Although expansions of neat n‐butane led to substantial conformational cooling under some circumstances, clusters were never seen without carrier gas. Both thin‐plate and tapered glass nozzles yielded clusters. Diffraction patterns of the clusters are characteristic of a liquidlike structure perhaps as cold as 100 K. No evidence for inclusion of carrier gas atoms in the clusters was found. Cluster scattering signals are stronger and show less noise than those which could be expected from bulk liquid by x‐ray or neutron diffraction. Their interference terms are dominated by nearest neighbor intermolecular C...H contacts. Information about the distribution of these contacts has not yet been deduced in computer simulations of liquid butane but should soon become available for comparison.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70517/2/JCPSA6-78-3-1265-1.pd

The Effect of Wind on the Rate of Heat Loss from Avian Cup-Shaped Nests

Forced convection can significantly influence the heat loss from birds and their offspring but effects may be reduced by using sheltered micro-sites such as cavities or constructing nests. The structural and thermal properties of the nests of two species, the spiny-cheeked honeyeater (Acanthagenys rufogularis) and yellow-throated miner (Manorina flavigula), were measured in relation to three wind speeds. Nest dimensions differ between the two species, despite the similar body mass of the incubating adults, however nest conductance is comparable. As wind speed increases, so does the rate of heat loss from the nests of both species, and further still during incubation recesses. The significance of forced convection through the nest is a near-doubling in heat production required by the parent, even when incubating at relatively low wind speeds. This provides confirmation that selecting a sheltered nest site is important for avian reproductive success

Putting the Earth into Science: Resource, Workshop and Field Trip for High School Science Teachers at GeoCanada 2010

Putting the Earth into Science is a classroom resource that takes an interdisciplinary approach to expanding Earth science content in Canadian high schools. In recent history, Earth science has struggled to be identified as a core subject in school curricula. Differing approaches of whether it is placed in social studies (geography) or science has resulted in identity confusion. Alternatively, it is often seen as a specialist area of study, and hence optional. As a solution to this problem, the National EdGEO Workshop Program has developed a series of curricula-based lesson plans to integrate Earth science topics into the core subjects of physics, chemistry, biology and mathematics. The program will attract teachers of diverse science disciplines, and deliver a meaningful educational experience and important career information to high school students who are largely unaware of how Earth science impacts their daily lives. Putting the Earth into Science was launched during a workshop and field trip offered to teachers across Canada in conjunction with GeoCanada 2010. Sommaire La Terre en science est une source référence d’activités pédagogiques interdisciplinaires visant à accroître le contenu en sciences de la Terre du programme secondaire des écoles canadiennes. Ces dernières années, les sciences de la Terre ont peiné s’imposer comme matière essentielle du programme scolaire. Selon l’approche, elles étaient tantôt incorporées aux sciences sociales (géographie), tantôt aux sciences physiques, d’où la confusion. Elles sont aussi perçues comme matière spécialisée, et optionnelles à ce titre. Comme solution, le National EdGEO Workshop Program a mis au point une série de plans de cours permettant d’intgérer des thèmes de sciences de la Terre aux matières obligatoires comme la physique, la chimie, la biologie et les mathématiques. Le programme intéressera les enseignants de diverses disciplines scientifiques, et leur proposera une démarche éducationnelle riche, et offrira aux éléves du secondaire les informations essentielles sur la profession, eux qui ignorent en grande partie l’impact des sciences de la Terre dans leur vie quotidienne. La Terre en sciences a été lancée officiellement à l’occasion de la tenue d’un atelier et d’une excursion offerts aux enseignants canadiens lors du congrès GeoCanada 2010

Electron diffraction studies of supersonic jets. I. Apparatus and methods

We describe the apparatus and methods used to obtain electron diffraction patterns of low‐temperature species produced from molecules seeded into supersonic expansions of helium or neon carrier gases. Although systems designed for molecular beam or spectroscopic studies are unsuitable for electron diffraction, alternative arrangements were found that give diffraction patterns of good quality. Characteristics of gas jets issuing from different nozzle designs are discussed. Procedures are outlined for separating the desired signal from considerable background scattering by the carrier gas and to correct for broad gas density profiles in analyses of diffraction data.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70889/2/JCPSA6-78-1-236-1.pd

Electron diffraction studies of supersonic jets. II. Formation of benzene clusters

Expansions of benzene at 1–10 mol % in neon or helium with various nozzle types have produced clusters of benzene molecules. Preliminary comparisons with intensities from the bulk liquid and with model calculations based on solid state crystal structures suggest that on the average the clusters are probably considerably larger than a 13 molecule unit, and have a vibrational temperature on the order of 100–150 K. Unlike clusters of spherical or quasispherical molecules previously found to pack in nearly crystalline arrays, benzene molecules appear to be unable to organize into regular arrays in the time of our experiments. Local order in clusters is similar but not identical to that in the solid, resembling that expected for a supercooled liquid. The present approach, exploiting several advantages of electron diffraction over alternative methods, shows promise as a new means of studying liquids or glasses.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71235/2/JCPSA6-78-1-243-1.pd

Natural bounds on herbivorous coral reef fishes

Humans are an increasingly dominant driver of Earth's biological communities, but differentiating human impacts from natural drivers of ecosystem state is crucial. Herbivorous fish play a key role in maintaining coral dominance on coral reefs, and are widely affected by human activities, principally fishing. We assess the relative importance of human and biophysical (habitat and oceanographic) drivers on the biomass of five herbivorous functional groups among 33 islands in the central and western Pacific Ocean. Human impacts were clear for some, but not all, herbivore groups. Biomass of browsers, large excavators, and of all herbivores combined declined rapidly with increasing human population density, whereas grazers, scrapers, and detritivores displayed no relationship. Sea-surface temperature had significant but opposing effects on the biomass of detritivores (positive) and browsers (negative). Similarly, the biomass of scrapers, grazers, and detritivores correlated with habitat structural complexity; however, relationships were group specific. Finally, the biomass of browsers and large excavators was related to island geomorphology, both peaking on low-lying islands and atolls. The substantial variability in herbivore populations explained by natural biophysical drivers highlights the need for locally appropriate management targets on coral reefs

Leadership and approaches to the management of workplace bullying

Leadership behaviour has been identified as an important antecedent of workplace bullying, since managers may prevent, permit or engage in the mistreatment of others. However, the issue of how managers respond when bullying occurs has received limited attention. With this in mind, the aim of this study was to explore how managers behave when bullying occurs in their work group, and to elucidate the contextual issues that underlie this behaviour. This was achieved through analysis of in-depth interviews with individuals involved in cases of bullying. The findings revealed a typology of four types of management behaviour in cases of bullying, each underpinned by contextual factors at the individual, group and organizational level. The study shows that the role of leadership in workplace bullying is more complex than previously thought, and suggests several ways in which managers and organizations could deal with bullying behaviour

Waste Management at SRS - Making It Happen

The past five years have witnessed a remarkable transition in the pace and scope of waste management activities at SRS. At the start of the new M&O contract in 1996, little was being done with the waste generated at the site apart from storing it in readiness for future treatment and disposal. Large volumes of legacy waste, particularly TRU and Low Level Waste, had accumulated over many years of operation of the site's nuclear facilities, and the backlog was increasing. WSRC proposed the use of the talents of the ''best in class'' partners for the new contract which, together with a more commercial approach, was expected to deliver more results without a concomitant increase in cost. This paper charts the successes in the Solid Waste arena and analyzes the basis for success

Rapid Preparation of Geometrically Optimal Battery Electrode Samples for Nano Scale X-ray Characterisation

Rechargeable lithium-based batteries are one of the key enabling technologies driving the shift to renewable energy, and research into novel technologies has intensified to meet growing demands in applications requiring higher energy and power density. The mechanisms behind battery degradation can be investigated across multiple length-scales with X-ray imaging methods; at the nanoscale severe constraints are imposed on sample size in order to obtain adequate signal to noise. Here, we present a novel lasermilling technique to prepare geometrically optimal samples for X-ray nano-tomography. Advantages of this technique include significantly reduced sample preparation time, and a suitable geometry for mosaic acquisition, enabling a larger field of view to be captured at high spatial resolution, thus improving statistics. The geometry of the resulting electrode remains highly suitable for nano-tomography, and yet permits in situ and operando experiments to be carried out on standard electrode coatings, providing new insights into transient phenomena whilst closely mimicking standard electrochemical cells