THE USE OF A GAS CHROMATOGRAPH TO OBTAIN DRYING RATES DATA THROUGH SIMPLE LABORATORY EXPERIMENTS

Abstract

A method making use of a gas chromatograph was investigated to acquire bound solvent drying rates. The solid to be dried was used as stationary phase in a chromatographic column, and the TCD detector was used to follow the decrease of solvent content of the effluent as inert gas was flown through the column. The measurement of the break-through curve allows the evolution of drying rate with time or solvent content to be obtained. The comparison of the experimental results with numerical simulation leads to the determination, through parametric adjustment, of the internal mass-transfer coefficient as a function of the solvent content during the second stage of bound solvent drying period. This parameter can lead to the value of the diffusivity as a function of solvent content.     

Establishing an objective basis for image compositing in satellite oceanography

This study strives to establish an objective basis for image compositing in satellite oceanography. Image compositing is a powerful technique for cloud filtering that often emphasizes cloud clearing at the expense of obtaining synoptic coverage. Although incomplete cloud removal in image compositing is readily apparent, the loss of synopticity, often, is not. Consequently, the primary goal of image compositing should be to obtain the greatest amount of cloud-free coverage or clarity in a period short enough that synopticity, to a significant degree, is preserved.To illustrate the process of image compositing and the problems associated with it, we selected a region off the coast of California and constructed two 16-day image composites, one, during the spring, and the second, during the summer of 2006, using Advanced Very High Resolution Radiometer (AVHRR) InfraRed (IR) satellite imagery. Based on the results of cloud clearing for these two 16-day sequences, rapid cloud clearing occurred up to day 4 or 5, followed by much slower cloud clearing out to day 16, suggesting an explicit basis for the growth in cloud clearing. By day 16, the cloud clearing had, in most cases, exceeded 95%. Based on these results, a shorter compositing period could have been employed without a significant loss in clarity.A method for establishing an objective basis for selecting the period for image compositing is illustrated using observed data. The loss in synopticity, which, in principle, could be estimated from pattern correlations between the images in the composite, was estimated from a separate time series of SST since the loss of synopticity, in our approach, is only a function of time. The autocorrelation function of the detrended residuals provided the decorrelation time scale and the basis for the decay process, which, together, define the loss of synopticity. The results show that (1) the loss of synopticity and the gain in clarity are inversely related, (2) an objective basis for selecting a compositing period corresponds to the day number where the decay and growth curves for synopticity and clarity intersect, and (3), in this case, the point of intersection occurred 3.2 days into the compositing period. By applying simple mathematics it was shown that the intersection time for the loss in synopticity and the growth in clarity is directly proportional to the initial conditions required to specify the clarity at the beginning of the compositing period, and inversely proportional to the sum of the rates of growth for clarity and the loss in synopticity. Finally, we consider these results to be preliminary in nature, and, as a result, hope that future work will bring forth significant improvements in the approach outlined in this study.     

Effects of Botrytis cinerea infection on Champagne wine foaming properties

Qualitative effects of Botrytis cinerea infection were studied by comparing the foaming properties of Champagnes obtained from healthy grapes with those from grapes infected by B cinerea. This is of particular interest when it is considered that the foaming properties of Champagne wines are important in terms of product attractiveness for the consumer. Experiments using artificial viewing equipment clearly showed the dramatic effects on Champagne foam characteristics when grape berries were highly infected. The speed at which liquid separated from the foam (expressed as liquid height L_S) in the glass depended largely on the level of infection for Chardonnary and Pinot noir wines (+268% for Chardonnary wines at 40% infection and +627% for Pinot noir wines at 20% infection). B cinerea infection reduced the time (L_T) at which liquid first appeared in the glass; for Pinot noir wines an infection level of 20% caused very rapid drainage. The time of pouring (P_T, ie the time to fill the glass under controlled conditions) also diminished considerably at an infection level of 20% for both Pinot noir and Pinot meunier wines (?74 and ?58% respectively). Mouldiness considerably altered the foam height observed 80 s (H₈₀) after the start of pouring (?83% for Pinot noir and ?89% for Pinot meunier at 20% infection). Champagne foamability was also quantified using a sparging technique to standardise effervescence. Foamability suffered considerably (?60 to ?65%) when the B cinerea infection level was 20% as compared to control Champagnes. All wines studied had low and very similar protein contents. Differences in the concentrations of these compounds, which are generally implicated in the formation of foam in sparkling wines, could not explain the differences in Champagne foaming properties observed here. © 2001 Society of Chemical Industry     

The anteater and the dreamer.

Reviews the book, Brain and psyche: The biology of the unconscious by Jonathan Winson (1985). Winson offers a "biology of the unconscious," based on his reading of psychoanalysis and his research in experimental neurophysiology. Given Winson's main area of professional activity, it is not surprising that the slant of this book is one of a neuroscientist. But Winson is no slouch in the Freud department either; he devotes 3 of 10 chapters to a well-expounded, somewhat selective, chronological account of the main events leading to the development of psychoanalytic thought. In tackling the challenge of such an integration, Brain and psyche makes a unique and valuable theoretical contribution. Many different types of experiences, along with their associated cognitive and emotional concomitants, will form relatively permanent traces in the brain and thus exert subsequent effects on behavior, by virtue of their being consolidated during critical periods. This is why, says Winson, so many patterns of behavior, adaptive or maladaptive, appear so fixed and immutable in an individual's personality. Dreams allow us to glimpse at the neurobehavioral process whereby, from early childhood on, behavioral strategies are laid down, modified, or consulted, a process that Winson calls the unconscious personality. But it is Winson's account of repression that is the most intriguing. Repression is a process that intervenes in the temporal space between the generation of an idea, emotional feeling, or sensory impression, and the subjective apperception of that experience. Winson makes the conceptual leap from experimental neurophysiology (he works mainly with the rat) to human psychodynamics. What seems to be missing is a middle step, some evidence from human brain research that could link the two domains. Winson has taken an important first step in bridging the chasm between laboratory and consulting room. What we need now is more data from the human side of the brain and behavioral sciences to bring these domains closer still. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Posttraumatic stress disorders in Vietnam veterans: Selected bibliographical addendum to Fairbank et al., Silver, and Arnold.

J. A. Fairbank et al (see record 1982-12226-001), presented a selected bibliography on contributions relevant to posttraumatic stress disorder (PTSD) in Vietnam veterans. Their selection included research and clinical reports found in psychological and medical journals, books and government publications, which were pertinent to epidemiology, etiology, symptomatology, and treatment of PTSD in Vietnam veterans, plus narratives by Vietnam veterans and research germane to PTSD from other conflicts. S. M. Silver (see record 1983-03626-001) updated Fairbank et al., with 171 since-published articles, reports, and other references. A. Arnold's (1987) bibliograpy contains over 1,000 clinical references, as well as accounts of the Vietnam War. This addendum is an attempt to update the enormous body of PTSD literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High energy dry coating mixing: Elements on velocities,temperatures and melting

In dry coating processes no liquid, solvent, binder or water, is required. This makes them advantageous compared to wet coating alternative: being low cost, no drying step required, environmentally friendly (no volatile organic compounds related problems) and simple in operation. But there is still a lack of fundamental knowledge of the implied mechanisms. Often the process itself has been empirically designed and is not always well characterized.In this work, some hydrodynamic elements are developed in a high energy mixer used for dry coating: the specific behavior of the Nara hybridizer NHS-0 is investigated. In the first part, recirculation velocities and temperatures are derived during the process, or when the purge is on. The effects of the pressure purge and of the rotor velocity on the purge and the effect of the rotation on the temperature increase are studied. In the second part, a simple experimental approach is carried out to derive qualitatively the local temperature inside the apparatus with the help of polymers with different melting temperatures. This approach illustrates a first step for dry coating application with waxes.     

STEM nanoanalysis of Au/Pt/Ti-Si3N4 interfacial defects and reactions during local stress of SiGe HBTs

Nanoscaled materials are attractive building blocks for hierarchical assembly of functional nanodevices, which exhibit diverse performances and simultaneous functions. We innovatively fabricated semiconductor nano-probes of tapered ZnS nanowires through melting and solidifying by electro-thermal process; and then, as-prepared nano-probes can manipulate nanomaterials including semiconductor/metal nanowires and nanoparticles through sufficiently electrostatic force to the desired location without structurally and functionally damage. With some advantages of high precision and large domain, we can move and position and interconnect individual nanowires for contracting nanodevices. Interestingly, by the manipulating technique, the nanodevice made of three vertically interconnecting nanowires, i.e., diode, was realized and showed an excellent electrical property. This technique may be useful to fabricate electronic devices based on the nanowires' moving, positioning, and interconnecting and may overcome fundamental limitations of conventional mechanical fabrication.     

Use of microwave dielectric loss for characterisation of natural rubber/carbon black composites

Summary Microwave dielectric loss spectroscopy (MDS) has shown remarkable potential as a tool for the observation of changes in elastomer network structure within the interphase region of natural rubber/ carbon black composites. During crosslinking (non elemental sulphur system) the dielectric loss progressively increased. However, during ageing at high temperature the dielectric loss decreased. Parallel studies on the unfilled matrix yielded no such variation in dielectric loss. It was therefore concluded that the changes in microwave responses were related to the development of the interphase during curing and its subsequent destruction during ageing. The microwave response was related to the composite mechanical properties as a function of ageing time. The effect of stabiliser was also investigated. Received: 13 September 1999/Revised version: 7 February 2000/Accepted: 10 February 2000     

Segmentation of store choice models using stated preferences

The understanding and modelling of consumer shopping behaviour can increasingly only be fully realised by reference to market segments. Disaggregate choice modelling methods are able to take account of such behavioural heterogeneity, but are hampered by the poor quality of observed choice data on which they are calibrated. This paper shows how a segmented modelling strategy may be developed using stated preference data, and illustrates the methodology using the example of grocery shopping in Cardiff, South Glamorgan.