On the evolution of non-axisymmetric viscous fibres with surface tension, inertia and gravity

We consider the free boundary problem for the evolution of a nearly straight slender fibre of viscous fluid. The motion is driven by prescribing the velocity of the ends of the fibre, and the free surface evolves under the action of surface tension, inertia and gravity. The three-dimensional Navier-Stokes equations and free-surface boundary conditions are analysed asymptotically, using the fact that the inverse aspect ratio, defined to be the ratio between a typical fibre radius and the initial fibre length, is small. This first part of the paper follows earlier work on the stretching of a slender viscous fibre with negligible surface tension effects. The inclusion of surface tension seriously complicates the problem for the evolution of the shape of the cross-section. We adapt ideas applied previously to two-dimensional Stokes flow to show that the shape of the cross-section can be described by means of a conformal map which depends on time and distance along the fibre axis. We give some examples of suitable relevant maps and present numerical solutions of the resulting equations. We also use analytic methods to examine the coupling between stretching and the evolution of the cross-section shape

Altered Sensory Feedback in Speech

This chapter reviews the effects temporal, spectral and intensity perturbations to auditory and vibratory feedback have on fluent speakers and PWS. Early work on Delayed Auditory Feedback (DAF) with fluent speakers, showed that speech errors arise, speakers increase voice level, speech is slowed, medial vowels in syllables are elongated and pitch is monotone. It has been claimed that short-delay DAF produces effects on speech fluency, rate and naturalness that are as good as other forms of altered sensory feedback although this has been contested. Another alternative would be to reduce dosage by ramping intensity of altered auditory feedback down after a dysfluency provided speech is fluent and switch it to its full level when the next episode of stuttering occurs. Overall, temporal delays to speech feedback have a robust effect on fluent speakers and PWS. In fluent speakers, DAF induces a range of disruptions to speech

Nanocrystalline diamond film for biosensor applications

In this study, we have developed a novel capacitive biosensor based oil interdigitated gold nanodiamond (GID-NCD) electrode for detection of C-reactive protein (CRP) antigen. CRP is one of the plasma proteins known as acute-phase proteins and its levels rise dramatically during inflammatory processes occurring in the body. It has been reported that CRP in serum can be used for risk assessment of cardiovascular diseases. The antibodies immobilization were confirmed by Fourier transform spectroscopy (FTIR) and contact angle measurements. In this capacitive biosensor, nanocrystalline diamond acting as a dielectric layer between the electrodes. The CRP antigen detection was performed by capacitive/dielectric-constant measurements. Our results showed that the response of NCD-based capacitive-based biosensor for CRP antigen was dependent on both concentration (25-800 ng/ml) as well as frequency (50-350 MHz). Furthermore, using optimized conditions, the biosensors developed in this study can be potentially used for detection of elevated level of risk markers protein in suspected subjects for early diagnosis of disease

Environments Past: Nostalgia in Environmental Policy and Governance

A variety of factors shape environmental policy & governance (EPG) processes, from perceptions of physical ecology and profit motives to social justice and landscape aesthetics concerns. Many scholars have examined the role of values in EPG, and demonstrated that attempts to incorporate (especially) nonmarket values into EPG are loaded with both practical and conceptual challenges. Nevertheless, it is clear that nonmarket values of all types play a crucial role in shaping EPG outcomes. In this paper, we explore the role of nostalgia as a factor in EPG. We examine literatures on environmental values, governance, and affect in light of their relationships to environmental policymaking, first as a means to decide whether or not nostalgia can be rightly described as an ‘environmental value.’ We suggest that, from a philosophical perspective, nostalgia is by itself environmentally neutral, and is not usefully described as a ‘value’. However, as an emotional state that longs to preserve or recover something of the past – whether fading or no longer present – that is fondly remembered, nostalgia does represent a potentially strong ‘motivator’ for EPG decisions. Despite this somewhat ambivalent assessment of nostalgia-as-environmental-value, we argue that nostalgia and nostalgic longing to return to the ‘better’ or ‘cleaner’ environments can lead to potentially significant impacts on ecosystems and landscapes, both positive and negative depending on what it is that people want to preserve or restore. Thus we conclude that we neglect understanding the role of nostalgia in EPG at our peril: first, because preservationist goals have always been an important part of environmental responsibility and second, because many people will be swayed regarding environmental action through a mobilization of nostalgia by political leaders and interest groups alike. We end our article with suggestion of avenues for further empirical investigation

On the predictions and limitations of the BeckerDoring model for reaction kinetics in micellar surfactant solutions

We investigate the breakdown of a system of micellar aggregates in a surfactant solution following an order-one dilution. We derive a mathematical model based on the Becker–Döring system of equations, using realistic expressions for the reaction constants fit to Molecular Dynamics simulations. We exploit the largeness of typical aggregation numbers to derive a continuum model, substituting a large system of ordinary differential equations for a partial differential equation in two independent variables: time and aggregate size. Numerical solutions demonstrate that re-equilibration occurs in two distinct stages over well-separated time-scales, in agreement with experiment and with previous theories. We conclude by exposing a limitation in the Becker–Döring theory for re-equilibration and discuss potential resolutions

Laserwire at the Accelerator Test Facility 2 with Sub-Micrometre Resolution

A laserwire transverse electron beam size measurement system has been developed and operated at the Accelerator Test Facility 2 (ATF2) at KEK. Special electron beam optics were developed to create an approximately 1 x 100 {\mu}m (vertical x horizontal) electron beam at the laserwire location, which was profiled using a 150 mJ, 71 ps laser pulse with a wavelength of 532 nm. The precise characterisation of the laser propagation allows the non-Gaussian transverse profiles of the electron beam caused by the laser divergence to be deconvolved. A minimum vertical electron beam size of 1.07 ${\pm}$ 0.06 (stat.) ${\pm}$ 0.05 (sys.) {\mu}m was measured. A vertically focussing quadrupole just before the laserwire was varied whilst making laserwire measurements and the projected vertical emittance was measured to be 82.56 ${\pm}$ 3.04 pm rad.Comment: 17 pages, 26 figures, submitted to Phys. Rev. ST Accel. Beam

An asymptotic theory for the re-equilibration of a micellar surfactant solution

Micellar surfactant solutions are characterized by a distribution of aggregates comprised predominantly of pre-micellar aggregates (monomers, dimers, trimers, etc.) and a region of proper micelles close to the peak aggregation number, connected by an intermediate region containing a very low concentration of aggregates. Such a distribution gives rise to a distinct two-timescale re-equilibration following a system dilution, known as the 1 and 2 processes, whose dynamics may be described by the Becker–Döring equations. We use a continuum version of these equations to develop a reduced asymptotic description that elucidates the behavior during each of these processes

Effect of Sediment Particle Size and Temperature on Fecal Bacteria Mortality Rates and the Fecal Coliform/Fecal Streptococci Ratio

Extended survival of fecal bacteria in sediment can obscure the source and extent of fecal contamination in agricultural settings. The variability in fecal coliform/fecal streptococci (FC/FS) ratios with time and discrepancies between observable fecal sources and measured FC/FS ratios in shallow surface water from agricultural watersheds may be explained by examining FC and FS mortality rates in response to ambient temperature and sediment particle size. We measured FC and FS mortality rates at three different temperatures and in three feces-amended sediments with different particle size in a laboratory study. In controlled conditions, using physiological saline to reduce cell death by osmotic shock, FC mortality rates exceeded FS mortality rates. These rates declined as sediment particle-size shrank and as temperature decreased. There was no interaction between these two factors in determining fecal bacteria persistence. The apparent half-lives of FCs exceeded those of FS, even though mortality rates were higher, because of FC regrowth shortly after deposition. The FC/FS ratio is influenced by temperature, the presence of sediment, and sediment particle size. In warm conditions, FC regrowth increases FC/FS ratios to levels indicative of human contamination even where none clearly exists. These factors interfere with the interpretation of the FC/FS ratio and contribute to the difficulty of its use in agricultural settings

The K-band spectrum of the Cataclysmic Variable RXJ 0502.8+1624 (Tau 4)

We present the K-band spectrum of the cataclysmic variable RXJ 0502.8+1624 (Tau 4). The spectrum shows a broad, smooth hump, with no absorption lines from the secondary star visible. This result indicates that the infrared light of this system is dominated by cyclotron emission, and, in combination with the optical spectrum and X-ray properties, suggests that Tau 4 is a polar-type cataclysmic variable (CV). The system was chosen for study because the broadband JHK colours of Tau 4 are consistent with an L-type dwarf, suggesting that this system might harbour an elusive sub-stellar secondary star. The result presented here, along with the recent discovery of cyclotron emission in the cataclysmic variable EF Eri, suggests that care must be taken when using the broadband JHK colours of CVs when targeting searches for sub-stellar secondary starsComment: 4 pages, to appear as research note in A&

Particle Size and Temperature Affect Fecal Bacteria Survival in Sediment

When cattle have direct access to streams, fecal bacteria concentrations in stream sediments increase. If these bacteria persist, and if the sediments are resuspended, fecal bacteria may also appear in surrounding water for extended periods. Why do fecal bacteria persist, since dry conditions, high acidity or alkalinity, sunlight, competition from native microbes, and extreme temperatures all diminish their populations in soil? The effects of these environmental factors are much reduced in sediment. Water protects fecal bacteria from desiccation and ultraviolet light. High temperatures can promote their regrowth in wet environments. Fecal bacteria also survive on fine-sized sediments in streams because the sediments have a high surface area. These factors may help explain our observations that streams flowing through pastures typically exceed Kentucky standards for primary contact water (200 fecal coliforms/100 ml) long after cattle depart. The fecal coliform/fecal streptococci ratio (FC/FS), is a tool in water quality assessment that diagnoses the source of fecal contamination, whether from people (FC/FS \u3e 4) or animals (FC/FS \u3c 0.1). The ratio is extremely variable and sensitive to the persistence of the indicator bacteria used in it. For example, we observed in central Kentucky streams that as the temperature increased during spring, the FC/FS ratio also increased. Fecal coliform growth shortly after manure deposition might explain some of the variability we have observed in our water monitoring studies. In this study we tried to account for the seasonal variability of FC/FS ratios in agricultural watersheds, and determine whether sediment particle size and water temperature interacted to influence fecal bacteria persistence and the FC/FS ratio