Creep in chipboard     

C. B. Pierce  J. M. Dinwoodie  B. H. Paxton 《Wood Science and Technology》1986,20(3):281-292

Summary A considerable amount of data has been collected over the past few years on the rupture life of particleboard. This information is particularly valuable at the present time because there is increasing interest in the use of particleboard as a structural material. This paper presents a conventional analysis of the time to failure of three commercially available brands of particleboard at 20°C and at three fixed levels of relative humidity. A linear relationship is assumed between the logarithm of time to failure and stress level, and an improvement is made in the usual method of analysis by including censored specimens. The regression lines are projected forward to give estimates of the stress levels that can be sustained for a particular design life. It is found that the regression lines for 30 per cent and 65 per cent rh may be combined, but the specimens at 90 per cent rh are significantly lower in strength at any given time. One of the MUF bonded boards performs significantly better than a second MUF board over the long term, and this gives added weight to the view that there are other factors in the make-up and production of the board that are at least as important as the resin type itself.  相似文献   

Creep in chipboard     

J. M. Dinwoodie  B. H. Paxton  Jo-Anne Higgins  D. J. Robson 《Wood Science and Technology》1991,26(1):39-51

Summary Ten samples from each of ten brands of commercial chipboard, covering a range of UF, MUF and PF resins, were stressed over a 5-year period at 30% of their short term ultimate bending strength, under protected external conditions. No relationship could be established for the term of the experiment between fluctuations in creep deflection and changes in environmental conditions. Exceptionally, for two short periods of time, relationships were established and these were in line with current views on mechano-sorptive behaviour. Differences in relative creep between the ten brands were significantly greater than those occurring between samples of any one brand. Although there were significant differences in relative creep among the six brands of MUF bonded boards, the relative creep of all these boards was significantly lower than those brands made with UF and high-alkaline cured PF resins. While most of the MUF bonded samples survived the duration of the experiment, all UF and PF samples failed before the end of the 5-year period. For the first 6 months of the experiment, the mean relative creep under protected external conditions was equal to, or slightly less than, that obtained in matched samples tested under a constant environment of 20°C 90% rh.  相似文献   

Estimation of detection probability in aerial surveys of antarctic pack-ice seals     

Colin Southwell  David Borchers  Charles G. M. Paxton  Louise Burt  William de la Mare 《Journal of Agricultural, Biological & Environmental Statistics》2007,12(1):41-54

We use line transect detection functions together with generalized linear and additive models to estimate detection probability when detection on the line (“g(0)”) may not be certain. The methods provide a flexible way of modeling detection probability for independent observer surveys, and for investigating the effects of explanatory variables. Analysis of data from an aerial survey of pack-ice seals produced g(0) estimates substantially below 1 for some observers (it varied from 0.80 to 0.98), demonstrated a fairly complex dependence of detection probability on covariates, and showed negative correlation between observers’ search width and their g(0). In addition to illustrating the utility of generalized additive models for capturing the effect of covariates on detection probability, the analysis suggests that detection functions may be sufficiently variable that use of g(0) correction factors obtained from other surveys would be inadvisable. We recommend that estimation of g(0) be considered for all aerial surveys; if g(0) is found to be very close to 1, estimation from subsequent surveys under the assumption that it is 1 may be reasonable, but without any estimation of g(0), the assumption that it is 1 is a matter of faith.  相似文献   

Sustainability and the moral community     

Kathryn Paxton George 《Agriculture and Human Values》1992,9(4):48-57

Three views of sustainability are juxtaposed with four views about who the members of the moral community are. These provide points of contact for understanding the moral issues in sustainability. Attention is drawn to the preferred epistemic methods of the differing factions arguing for sustainability. Criteria for defining membership in the moral community are explored; rationality and capacity for pain are rejected as consistent criteria. The criterion of having interests is shown to be most coherent for explaining why all living humans belong to the moral community. This criterion allows inclusion of future generations as well, and extends to animals and plants membership in the moral community. Inferences are drawn that food sufficiency advocates hold only presently living persons to be full-fledged members of the moral community, but that this view is internally inconsistent. Stewards should agree that all living things are members of the moral community. A distinction between welfare interests and ulterior interests allows the steward to include the aims of those who argue for sustainability as community without committing some of their errors. Community advocates argue that essential values and virtues will be lost is the culture of agriculture is transformed. I argue that community advocates may fail to pass on our most important virtue — justice — without such a transformation.  相似文献   

Attempts, by blood transfusion, to replace blood loss due to Haemonchus placei infection     

W M Fitzsimmons  E Harness 《The Veterinary record》1969,84(2):49-50

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Build-up and subsequent decline of residues of quintozene and hexachlorobenzene in lettuce in sequential crops     

Albert R. P. Paxton  David Purser 《Pest management science》1982,13(4):401-406

The build-up and decline of quintozene and hexachlorobenzene residues in protected lettuce, resulting from one to five treatments of the soil (each of 35 g m-2) with a quintozene formulation, have been studied. Residue levels were monitored in each experimental crop during growth until harvest. Residues in the soil at harvest were also determined. Quintozene residues in the harvested lettuce were in the range < 0.02–0.80 mg kg^?1 and those of hexachlorobenzene were in the range < 0.02–0.05 mg kg^?1 (expressed on a fresh weight basis). Residue levels in the soil were 5.4–231 mg kg^?1 for quintozene, and 0.20–5.4 mg kg^?1 for hexachlorobenzene (expressed on a dry weight basis). Under the experimental conditions of the trial there was no significant build-up of quintozene or hexachlorobenzene in harvested lettuce, even after five treatments to the same site.  相似文献   

The surgical transfer of immature and mature Fasciola hepatica into the biliary system of the goat     

D L Hughes  E Harness  D C Davies  M N Hoare 《Research in veterinary science》1973,15(1):120-122

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The recovery after oral infection of immature Fasciola hepatica from the peritoneal cavity of two strains of mice     

E Harness  T G Doy  D L Hughes 《Research in veterinary science》1973,15(3):393-395

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The spirit of the dog: an illustrated history. By Tamsin Pickeral,with illustrations by Astrid Harrison. Allen and Unwin,Crows Nest, 2012. 288 pages. Price $49.99. ISBN 978 1 74331 125 7.     

David Paxton 《Australian veterinary journal》2012,90(12):489-489

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Sex ratio changes in the long-term Windermere pike and perch sampling program   总被引：1，自引：1，他引：0  

C. G. M. Paxton  J. M. Fletcher  D. P. Hewitt  I. J. Winfield 《Ecology of Freshwater Fish》1999,8(2):78-84

Abstract– Analysis of the Windermere (England), Perca fluviatilis (1965–1997) and Esox lucius (1943-1997) fishery data indicates there have been substantial changes in sex ratios through time. In the case of perch, a 1976 perch disease outbreak substantially skewed the sex ratio in favor of females. It took over a decade for the fishery to recover to its pre-1976 state. In the case of pike, both catch and year-class data are female biased, but this bias has significantly weakened through time. This trend towards proportionately more males through time may reflect an effect of increasing spring temperatures or an evolutionary or phenotypic response to female-biased fishing pressure.  相似文献