Thermal stress analysis of ceramic gas-path seal components for aircraft turbines

Stress and temperature distributions were evaluated numerically for a blade-tip seal system proposed for gas turbine applications. The seal consists of an abradable ceramic layer on metallic backing with intermediate layers between the ceramic layer and metal substrate. The most severe stresses in the seal, as far as failure is concerned, are tensile stresses at the top of the ceramic layer and shear and normal stresses at the layer interfaces. All these stresses reach their maximum values during the deceleration phase of a test engine cycle. A parametric study was carried out to evaluate the influence of various design parameters on these critical stress values. The influences of material properties and geometric parameters of the ceramic, intermediate, and backing layers were investigated. After the parametric study was completed, a seal system was designed which incorporated materials with beneficial elastic and thermal properties in each layer of the seal. An analysis of the proposed seal design shows an appreciable decrease in the magnitude of the maximum critical stresses over those obtained with earlier configurations

Letter by Scheitz et al regarding article, "Randomized controlled trial of early versus delayed statin therapy in patients with acute ischemic stroke: ASSORT trial (administration of statin on acute ischemic stroke patient)"

No abstract available

Symptomatology under storm conditions in the north atlantic in control subjects and in persons with bilateral labyrinthine defects

Motion sickness under conditions of stress and anxiety - role of vestibular apparatu

Restricted dog leucocyte antigen (DLA) class II haplotypes and genotypes in Beagles

AbstractBeagles are commonly used in vaccine trials as part of the regulatory approval process. Genetic restriction within this breed and the impact this might have on vaccine responses are rarely considered. This study was designed to characterise diversity of dog leucocyte antigen (DLA) class II genes in a breeding colony of laboratory Beagles, whose offspring are used in vaccine studies. DLA haplotypes were determined by PCR and sequence-based typing from genomic DNA extracted from blood. Breeding colony Beagles had significantly different DLA haplotype frequencies in comparison with pet Beagles and both groups showed limited DLA diversity. Restricted DLA class II genetic variability within Beagles might result in selective antigen presentation and vaccine responses that are not necessarily representative of those seen in other dog breeds

The effect of water immersion on perception of the oculogravic illusion in normal and labyrinthine-defective subjects

Perception of oculogravic illusion in normal and labyrinthine-defective subjects related to water immersio

Electroweak Theory Without Higgs Bosons

A perturbative SU(2)_L X U(1)_Y electroweak theory containing W, Z, photon, ghost, lepton and quark fields, but no Higgs or other fields, gives masses to W, Z and the non-neutrino fermions by means of an unconventional choice for the unperturbed Lagrangian and a novel method of renormalisation. The renormalisation extends to all orders. The masses emerge on renormalisation to one loop. To one loop the neutrinos are massless, the A -> Z transition drops out of the theory, the d quark is unstable and S-matrix elements are independent of the gauge parameter xi.Comment: 27 pages, LaTex, no figures; revised for publication; accepted by Int. J. Mod. Phys. A; includes biographical note on A. F. Nicholso

The results of a cattle feeding test

The problem of most vital importance to the cattle feeder of the middle west at the present day is, how to produce beef more economically. The marked advance in the value of farm lands and the strenuous competition of the range territory coupled with the high priced feeding-stuffs have materially changed conditions from what they were less than two decades ago. Can he afford to feed fifty-five or sixty cent corn to cattle and hope to realize a profit? Can he, by the addition of some by-product or condimental food, secure better returns from the corn fed? These have been during the past year and are at the present day, very perplexing problems to the feeder. He has heard it stated that some of the by-products of corn, flaxseed or cottonseed when fed with corn will give much better returns than corn alone. He has been informed by the “stock food man” that a little stock food fed in conjunction with corn will increase his returns from fifty to one hundred per cent., this being due to the fact that the stock food has the power of increasing the appetite of the animal also of stimulating the digestive organs to such an extent that a much larger proportion of the corn consumed by the animal is digested