Diffusion and convection of gaseous and fine particulate from a chimney

Particle dispersion from a high chimney is considered and an expression for the subsequent concentration of the particulate deposited on the ground is derived. We consider the general case wherein the effects of both diffusion and convection on the steady state ground concentration of particulate are incorporated. Two key parameters emerge from this analysis: the ratio of diffusion to convection and the nondimensionalised surface mass transfer rate. We also solve the inverse problem of recovering these two parameters given the boundary concentration profile and provide an estimate of the concentration flux above the chimney stack

A laboratory investigation of the variability of cloud reflected radiance fields

A method to determine the radiative properties of complex cloud fields was developed. A Cloud field optical simulator (CFOS) was constructed to simulate the interaction of cloud fields with visible radiation. The CFOS was verified by comparing experimental results from it with calculations performed with a Monte Carlo radiative transfer model. A software library was developed to process, reduce, and display CFOS data. The CFSOS was utilized to study the reflected radiane patterns from simulated cloud fields

A study of morphology, provenance, and movement of desert sand seas in Africa, Asia, and Australia

A description and classification of major types of sand seas on the basis of morphological pattern and lineation are discussed. The steps involved in analyzing the patterns of deposits on ERTS-1 imagery, where the visible forms are mostly dune complexes rather than individual dunes are outlined. After completion of thematic maps portraying the pattern and lineation of the sand bodies, data on directions and intensity of prevailing and other winds are plotted on corresponding bases, as a preliminary to determination of internal structures through ground truth

Porous squeeze-film flow

The squeeze-film flow of a thin layer of Newtonian fluid filling the gap between a flat impermeable surface moving under a prescribed constant load and a flat thin porous bed coating a stationary flat impermeable surface is considered. Unlike in the classical case of an impermeable bed, in which an infinite time is required for the two surfaces to touch, for a porous bed contact occurs in a finite contact time. Using a lubrication approximation an implicit expression for the fluid layer thickness and an explicit expression for the contact time are obtained and analysed. In addition, the fluid particle paths are calculated, and the penetration depths of fluid particles into the porous bed are determined. In particular, the behaviour in the asymptotic limit of small permeability, in which the contact time is large but finite, is investigated. Finally, the results are interpreted in the context of lubrication in the human knee joint, and some conclusions are drawn about the contact time of the cartilage-coated femoral condyles and tibial plateau and the penetration of nutrients into the cartilage

Squeeze-Film Flow in the Presence of a Thin Porous Bed, with Application to the Human Knee Joint

Motivated by the desire for a better understanding of the lubrication of the human knee joint, the squeeze-film flow of a thin layer of Newtonian fluid (representing the synovial fluid) filling the gap between a flat impermeable surface (representing the femoral condyles) and a flat thin porous bed (representing the articular cartilage) coating a stationary flat impermeable surface (representing the tibial plateau) is considered. As the impermeable surface approaches the porous bed under a prescribed constant load all of the fluid is squeezed out of the gap in a finite contact time. In the context of the knee, the size of this contact time suggests that when a person stands still for a short period of time their knees may be fluid lubricated, but that when they stand still for a longer period of time contact between the cartilage-coated surfaces may occur. The fluid particle paths are calculated, and the penetration depths of fluid particles into the porous bed are determined. In the context of the knee, these penetration depths provide a measure of how far into the cartilage nutrients are carried by the synovial fluid, and suggest that when a person stands still nutrients initially in the fluid layer penetrate only a relatively small distance into the cartilage. However, the model also suggests that the cumulative effect of repeated loading and unloading of the knees during physical activity such as walking or running may be sufficient to carry nutrients deep into the cartilage

Interpreting the Atmospheric Neutrino Anomaly

We suggest that the atmospheric neutrino anomaly observed in the Super-Kamiokande (and other) experiments results from the combined effects of muon-neutrino to tau-neutrino oscillations with a Delta m^2 value of approximately 0.4 eV^2 and oscillations between muon neutrinos and electron neutrinos (and vice-versa) with 0.0001 < Delta m^2 < 0.001 eV^2. With an appropriate choice of a three-neutrino mixing matrix, such a hypothesis is consistent with essentially all neutrino observations.Comment: 12 pages, 2 eps figures, Latex2e, elsart style, submitted to Physics Letters B --REV2-- Updated figure 1 and added figure 2: Super-K single R dat

Stryker Osteonics: Prosthetic Knee Joint

We examine, within a simple bearing model of a knee joint that only consideres pure sliding, the effect of the presence of a small vertical hole in the load area on the fluid film properties. The calculations indicate that fluid is entrapped in such a hole, which, for constant load, causes a smaller minimal film separation of the two surfaces. This will lower the horizontal friction, but may also bring about surface contact in high load situations

Dynamic performance of detuned ridge waveguide AlInGaAs distributed feedback laser diodes

The dynamic behavior of AlInGaAs ridge waveguide distributed feedback lasers is reported in this work covering five detuned wavelengths between 1291 nm and 1326 nm for a laser active layer optical peak gain design centered at 1310 nm at room temperature. The detuning is achieved by modifying the laser grating pitch that performs the mode selection within the laser cavity simultaneously across a single processed wafer. The dynamic behavior is evaluated using the resonance frequencies of the detuned lasers measured at a range of injection currents for heatsink temperatures of 25°C and 85°C. The results confirm that a speed improvement can be achieved at 25°C by detuning the laser to shorter wavelengths. However, the results also show that a lower direct modulation bandwidth at 85°C makes the shorter wavelength design less attractive. For communications applications such as 10 Gbps uncooled operation, this trade-off between detuning and modulation bandwidth imply an optimum around −2 nm to +8 nm detuning (measured at 25°C)

Improving continence services for older people from the service-providers' perspective: a qualitative interview study

This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 3.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial.Objective To examine in depth the views and experiences of continence service leads in England on key service and continence management characteristics in order to identify and to improve our understanding of barriers to a good-quality service and potential facilitators to develop and to improve services for older people with urinary incontinence (UI). Design Qualitative semistructured interviews using a purposive sample recruited across 16 continence services. Setting 3 acute and 13 primary care National Health Service Trusts in England. Participants 16 continence service leads in England actively treating and managing older people with UI. Results In terms of barriers to a good-quality service, participants highlighted a failure on the part of commissioners, managers and other health professionals in recognising the problem of UI and in acknowledging the importance of continence for older people and prevalent negative attitudes towards continence and older people. Patient assessment and continence promotion regardless of age, rather than pad provision, were identified as important steps for a good-quality service for older people with UI. More rapid and appropriate patient referral pathways, investment in service capacity, for example, more trained staff and strengthened interservice collaborations and a higher profile within medical and nurse training were specified as being important facilitators for delivering an equitable and high-quality continence service. There is a need, however, to consider the accounts given by our participants as perhaps serving the interests of their professional group within the context of interprofessional work. Conclusions Our data point to important barriers and facilitators of a good-quality service for older people with UI, from the perspective of continence service leads. Further research should address the views of other stakeholders, and explore options for the empirical evaluation of the effectiveness of identified service facilitators.Funding was received from the New Dynamics of Ageing Programme, led by the Economic & Social Research Council, UK (grantnumber RES-353-25-0010)