Numerical modelling of the scattering of elastic waves in plates

This paper describes the application of finite difference methods to the calculation of the scattering of elastic waves. The emphasis is on cracklike defects in plates, and it is shown that a common numerical technique can span a range of wavelengths from Lamb waves to ultrasonic waves with many reflections from the surfaces of the plate. Quantitative results are given for the scattering of Lamb waves and ultrasonic shear waves from surface-breaking cracks.     

The kinetics of platelet production and destruction in man

Platelets are derived from the cytoplasm of mature marrow megakaryocytes through cytoplasmic demarcation by invaginating plasma membrane and fragmentation of cytoplasmic protrusions into marrow sinusoids. Thereafter, platelets survive in the circulation for about 9 to 10 days. Platelet production is regulated to meet the demands for circulating platelets by means of humoral stimulation. Mean platelet volume, about 10 fl, remains constant over a wide range of survival times and production rates. In normal individuals platelets are produced at a rate of 35 X 10(9)/1/day (or 2.5 X 10(10) fl/kg body wt.) and reflect directly the marrow megakaryocyte cytoplasmic mass. Platelets have important roles in haemostasis, arterial thrombogenesis, wound healing and atherogenesis. Measurements of platelet survival are useful as an in vivo indicator of platelet participation in pathogenesis and pharmacological prevention of these processes. At present platelet survival is most reliably determined by in vitro radiochromium population labelling. 51Cr-platelet disappearance curves require objective unbiased analysis, preferably by non-linear gamma function least squares computer fitting procedures.     

Preparation of cryoprecipitated factor VIII concentrates

Factors affecting the yield of factor VIII in cryoprecipitate have been investigated in the context of a blood component program. Both in vitro and in vivo measurements were used to assess the effects of critical variables on the yield of factor VIII activity. Variables such as anticoagulant, plastic bag, mixing during collection, and platelet contamination had no significant effect on yield of factor VIII activity in cryoprecipitate. Among the most critical factors affecting yield were storage time of whole blood and procedures for freezing, thawing, and reconstitution. The following procedures were found to assure a 60 per cent recovery of factor VIII in cryoprecipitate: 1)processing of whole blood within six hours of collection; 2)use of a technique to freeze plasma within 30 minutes either in a -70 C ethanol bath or -85 C freezer; 3)rapid thawing (1 1/2 hour or less) in a 4 C circulating water bath; 4)centrifugation at 4,500 X g for 10 minutes at 4 C followed by draining of the supernatant in a 4 C cold room; 5) storage of the precipitate at -20 C until ready for use; 6) thawing in a 37 C water bath for at least 15 minutes followed by addition of 20 ml of 0.15 M saline for a 20 minute period at room temperature, and gentle mixing before pooling units for transfusion. The recovery of factor VIII in cryoprecipitate appears to be limited to about 65 per cent by its solubility in plasma at 4 C. Therefore, further effort to increase the amount available for treatment should involve improving the supply of plasma for its preparation and decreasing the cost of processing.     

The use of molybdenum for the prevention of nutritional copper poisoning in housed sheep

An experiment was designed to investigate the practical possibility of incorporating small quantities of molybdenum salts into the high copper diets of intensively fattening lambs to prevent or reduce the gradual accumulation of copper from feed. At slaughter (14 weeks of age) lambs which had received Mo supplement (7.7 ppm Mo) showed liver copper levels which were 40.1 per cent lower than those in the control group which, in turn, presented a mean liver copper concentration near the upper limit of the normal range for adult sheep. Changes in blood ceruloplasmin and SGOT levels and in the comparative rate of accumulation of liver copper indicated that the addition of ammonium molybdate to the concentrate diet might be a useful method of reducing the risk of nutritional copper poisoning in housed sheep.     

Consumer evaluation of novel kiwifruit: willingness‐to‐pay

This paper introduces a research methodology that adds sophistication to the innovation process for agricultural goods. In recognition of the importance of innovation for the long‐term success of firms and the need for market analysis that goes beyond traditional sensory and consumer preference testing, it is demonstrated how to measure the monetary value consumers place on new market goods. In experimental markets, New Zealand (NZ) consumers were willing to pay on average approximately NZ$0.44 per 100 g to exchange the common green‐fleshed Hayward variety for a new‐to‐market red‐ and yellow‐fleshed kiwifruit variety. At the time of the study this was equivalent to a 179% retail price premium. Knowledge that this new variety was not genetically modified increased the price premium to 240%. These results were elicited from convenience samples and should be treated with caution if used as the sole basis for price setting. Copyright © 2005 Society of Chemical Industry     

Axillary skin: biology and care

In skin care, the axilla is a biologically unique site requiring specialized attention and care. This area of skin is often subject to hair removal techniques, such as shaving and plucking. These procedures damage the skin leading to erythema and dryness in the short term, and in some cases, post-inflammatory hyperpigmentation (PIHP) in the long term. This study will (i) briefly review the biology and unique properties of axillary skin, and (ii) describe the characteristics of the irritation and damage induced by contemporary skin care habits and resolution of these responses by the use of efficacious skin moisturizing technology. With respect to the latter, we propose that there are five groups of compounds, defined according to their mechanism of action, which are particularly relevant to the care of damaged axillary skin.     

Microwave Inspection of Luggage for Contraband Materials Using Imaging and Inverse-Scattering Algorithms

Abstract

Microwave inspection techniques can determine frequency-dependent complex permittivity of local regions within a nonmetallic suitcase. These dielectric data can provide the additional information needed to identify contraband material, such as explosives and drugs. Although X-ray techniques provide high-resolution images of luggage contents, they cannot easily discriminate between various organic materials such as foodstuffs, paper products, and plastics. However, because common high-explosive materials and compressed-powder narcotics have dielectric properties similar to those of common plastics, dielectrometric evaluation can discriminate between contraband materials and other organics based on their moisture content or, in the case of cosmetic products, the presence of polar solvents. This paper describes the microwave luggage-inspection problem and presents an approach to discriminating and characterizing contraband materials in this environment.     

Modeling ultrasonic inspection of austenitic welds

The strength of austenitic welds will be considerably reduced if cracks are present. To guard against this possibility good workmanship is essential; quality is monitored by inspecting the welds after manufacture. Ultrasound is the favored method of inspection but there are difficulties associated with this in the coarse-grained columnar weld structures often associated with austenitic materials. We present two different approaches to modeling such inspections: ray tracing and full numerical solution of the governing wave equation. We show that the two approaches, although very different in physical nature and numerical method, give similar and consistent results.     

Charge-sensitive secondary electron imaging of diamond microstructures

The surface orientation and detailed defect microstructure of polycrystalline diamond can be observed in a scanning electron microscope through local changes in the surface conductivity. The electron contrast in uncoated samples is straightforward to distinguish when the rms surface roughness is less than about 2 nm. This degree of smoothness occurs on some of the faceted surfaces of individual diamond grains but can also be achieved by polishing. The contrast, observable only in the secondary electron imaging mode, shows a strong dependence on both beam voltage and current. It is postulated that the contrast is produced solely by the differential rate at which the electron beam-induced charge can be locally dissipated through crystalline defects and grain boundaries in the otherwise highly nonconductive diamond matrix. The appearance of the charge-related contrast requires that highly connected pathways exist between the crystalline defects and the high-angle grain boundaries.