Andrew's Cross Research Articles

Females on top in spider sex

Losing the mating game can mean losing your life, if you are a male St Andrew's Cross spider. .

Linear generation theory of 2D and 3D periodic internal waves in a viscous stratified fluid

We investigated analytically and experimentally 2D and 3D periodic internal waves generated by small harmonic oscillations of a plate and of an impermeable vertical cylindrical tube in an exponentially stratified viscous fluid. The linearized governing equations were solved by an integral transform method. The exact boundary conditions on the surface of a body, as well as the governing equations are satisfied if, in addition to propagating internal waves, internal boundary currents on the emitting surface are taken into account. On the basis of these two forms of fluid motion, we constructed a complete linear theory of the wave generation, without any external parameters. We calculated wave amplitudes and evolution along the beam of the so-called ‘St. Andrew's Cross’ wave shape, namely the number of maxima in the wave amplitude cross-section. The spatial decay of the wave was different in 2D and 3D problems due to geometry. The distance from the source, where transition from a bi-modal beam to the uni-modal beam takes place, is defined. Small viscosity smoothes out the singularity that arises in the wave field along the inviscid characteristics and in the critical angles. Experimental observations and probe measurements of a periodic wave pattern confirmed the theoretical results for the far field wave structure. The absolute values of calculated wave amplitudes differed from the experimental values by a factor less than 1.5. Indirect evidence of the internal boundary currents in Schlieren photographs of the flow pattern were presented. Copyright © 2001 John Wiley & Sons, Ltd.

Impingement heat transfer by jet issuing from a cross-shaped nozzle

Heat transfer characteristics and flow patterns were measured over a plate for various separation distances between the nozzle exit and target plate when air issues from a sharp-edged cross-shaped nozzle and impinges on a plate. The local heat transfer coefficients in the radial direction for different circumferential positions were calculated using the wall temperatures measured by means of thermocouples, and flow patterns were observed using an oil-titanium IV oxide method. The isotherms of the infrared images were also measured using an infrared radiometer with a two-dimensional array of indium-antimony (InSb) sensors. The geometric axes were switched as a result of the self-induced velocity of a vortex filament; the convex corners became flat and the concave corners generated outward ejection. The distributions of the iso-heat transfer coefficient contours correspond well to the flow pattern and the isotherm contours. These contours extended diagonally and demonstrated the St. Andrew's cross pattern for short separations, subsequently changing to an octagonal pattern, and then becoming circular at large separations. The correspondence of the heat transfer characteristics to the flow behavior, as well as the heat transfer mechanism are also described. © 1998 Scripta Technica, Heat Trans Jpn Res, 27(3): 192–204, 1998

Impingement Heat Transfer by Jet Issuing from Cross-Shaped Nozzle.

Heat transfer characteristics and flow patterns were measured over the plate for various separation distances between the nozzle exit and target plate when the air issuing from a sharpedged cross-shaped nozzle impinges on the plate. The local heat transfer coefficients in the radial direction for different circumferential positions were calculated using the wall temperatures measured by means of thermocouples, and the flow patterns were observed using a oil-titanium IV oxide method. The isotherms of the infrared images were also measured using an infrared radiometer with a two-dimensional array of InSb sensors. The geometric axes were switched due to the self-induced velocity of a vortex filament ; the convex corners became flat and the concave corners generated outward ejection. The distribution of the iso-heat-transfer-coefficient contours corresponds well to the flow pattern and the isotherm contours. These contours extended diagonally and demonstrated the Andrew's cross pattern for the short separations, subsequently becoming the octagonal patten, and then becoming circular at large separations. The correspondence of the heat transfer characteristic to the flow behaviors, and the heat transfer mechanism were also described.

Proton Chemical-Shift Spectra

Three related methods are explored for obtaining high-resolution proton spectra without spin–spin splittings, termed “chemical-shift spectra.” They are based on two-dimensionalJspectroscopy, where theF1dimension is derived by Fourier transformation of spin-echo modulation. The first technique superimposes theJspectrum on its reflection in theF1= 0 axis, creating multiplet patterns in the form of a St. Andrew's cross. The other two techniques purge certain antiphase product-operator terms, either by dispersal in an inhomogeneous effective radiofrequency field oriented at the magic angle (54.7°) or by means of azfilter. In all three cases, the two-dimensional multiplets are separated by means of a symmetry filter and their centers are taken as a measure of the respective chemical shifts. The 400 MHz proton chemical-shift spectrum of 4-androsten-3,17-dione is presented as an illustrative example. Good separation is achieved, even for interpenetrating spin multiplets with near degeneracies in their chemical shifts. Complications due to strong-coupling effects are discussed.

Rigid latticed steel frames: two large-scale tests and failure predictions

This work is concerned with the predictions of failure under static load for two identical free-standing latticed cantilever frames. Each structure was 3 m high and consisted of three storeys with panel points 1 m apart; in plan it was 1 m2; its diagonals were at 45° in the form of St. Andrew's cross; all joints were welded and were considered rigid. The four bases were bolted to the laboratory floor and the static load was applied at the top as two compressive horizontal forces parallel to the sides of the structure. The individual members were all solid mild steel round rods; the verticals were of uniform cross section of 25.4 mm in diameter with a slenderness of 157; the horizontal cross-arms were of uniform cross section of 19 mm in diameter; and the diagonals were of uniform cross section of 15.9 mm in diameter. The diagonals were cut at their mid-lengths and welded to give a flush joint.The total horizontal loads that caused failure of the two structures were 79.6 and 79.2 kN. In both cases failure occurred by the sudden buckling of one of the bottom-storey vertical legs, inwards towards the centre of the structure. Also upon failure, the diagonals in the bottom storey of the compression face buckled inwards and the compression diagonal of the side contiguous to the buckled leg also buckled.Three elastic stiffness matrices were used to predict the failure loads: (1) linear with yield criterion, 116 kN; (2) stability with change in sign of the total potential energy, 66 kN; and (3) bowing with the criterion of maximum curvature of the load–deflection curve, 80 kN. The failure loads of the two structures were thus accurately predicted by the bowing matrix. Key words: latticed rigid frames, large-scale tests, bowing matrix, steel.

Technique for the management of anterior flail chest.

A technique for the management of anterior flail chest consisting of osteosynthesis and the positioning of two long Kirschner wires behind the sternum in the form of a St Andrew's cross is described. The procedure is easy to perform, the patient is ambulant early, and the results are good.

Internal and inertial waves in a viscous rotating stratified fluid

The effects of viscosity on the propagation of a St. Andrew's cross wave which is generated by a simple-harmonic localized disturbance in a rotating stratified fluid are considered. A similarity solution of the linearised equations shows that the velocities decay and that the wave width increases away from the disturbance. Previous solutions in a stratified non-rotating fluid are recovered by letting the rotation tend to zero. The solutions are also valid in the limit of a homogeneous rotating fluid. Further solutions for waves in a realistic ocean and in an isothermal atmosphere on a rotating Earth are also included.

Road Obstruction Lanterns

THE General Electric Co., Ltd., has developed a road obstruction lantern which complies strictly with the Lighting (Restrictions) Order, 1940. The use of these electric lanterns for fixing to street bollards or other supports has many advantages. Not only does it mean a saving ranging from Id. to 6d. per lamp per day, but it also saves in oil and man-power. According to Roads and Road Construction of June 1, in one London borough alone the saving effected in this way amounts to nearly £5,000 a year. The G.E.C. lantern is constructed of lead-coated sheet steel and has three sides, stencilled with the approved St. Andrew's Cross sign and backed with white opal glass. Inside are a detachable baffle and a B.C. lamp-holder for use with a 15-watt pearl Osram lamp. This provides the correct amount of light (0-5 candle per square foot) on the crosses. The lamp is easily accessible for wiring and maintenance. The lantern is supplied finished with either black or white outside. A two-lamp unit is preferred by some authorities because of the advantages of ensuring that there is a light on the island even if one lamp fails. The cost of the G.E.C. two-lamp lantern is little greater than that of the standard unit.

III —The Cruciform Muscle of Lamellibranchs

In 1900 von Ihering directed attention to the presence in certain Lamellibranchs of a special muscle lying in the posterior portion of the ventral mantle edge, close to the inner end of the inhalent siphon. This muscle consisted of two strands, each running diagonally from an origin on one valve to be inserted on the other, and crossing one another in the mid-ventral line so as to form a muscular apparatus with the appearance of a St Andrew's cross. He regarded this cruciform muscle as a specially differentiated group of fibres belonging to the pallial edge, acting as an accessory adductor muscle, a point of view in which he has been followed by all subsequent observers. To this von Ihering added the speculation that it had been by some similar process of specialisation of marginal pallial muscle fibres that the two other true adductor muscles of Lamellibranchs had originated.

St. Andrew's Cross

St. Andrew's Cross Get access A. R. Bayley A. R. Bayley Search for other works by this author on: Oxford Academic Google Scholar Notes and Queries, Volume s10-X, Issue 243, 22 August 1908, Page 155, https://doi.org/10.1093/nq/s10-X.243.155a Published: 22 August 1908

St. Andrew's Cross

St. Andrew's Cross

St. Andrew's Cross

St. Andrew's Cross

St. Andrew's Cross

Journal Article St. Andrew's Cross Get access J. Knox Laughton J. Knox Laughton Search for other works by this author on: Oxford Academic Google Scholar Notes and Queries, Volume s10-IX, Issue 215, 8 February 1908, Page 114, https://doi.org/10.1093/nq/s10-IX.215.114c Published: 08 February 1908

St. Andrew's cross

St. Andrew's cross

St. Andrew's cross

St. Andrew's cross

St. Andrew's cross

St. Andrew's cross Get access Alice Alice Search for other works by this author on: Oxford Academic Google Scholar Notes and Queries, Volume s7-II, Issue 46, 13 November 1886, Page 388, https://doi.org/10.1093/nq/s7-II.46.388f Published: 13 November 1886

St. andrew's cross

Journal Article St. andrew's cross Get access E. H. E. H. Search for other works by this author on: Oxford Academic Google Scholar Notes and Queries, Volume s3-X, Issue 259, 15 December 1866, Page 472, https://doi.org/10.1093/nq/s3-X.259.472d Published: 15 December 1866