Animal health in Australia     

A. G. Hunter 《Tropical animal health and production》1985,17(4):192-192

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Wood drying and Fick's second law     

A. J. Hunter 《Wood Science and Technology》1996,30(5):355-359

Summary The diffusion equation (sometimes referred to as Fick's second law) is derived in terms of water movement under the action of capillary forces. The mass diffusivity is thereby expressed in terms of the capillary diffusion coefficient. A numerical calculation is given for yellow poplar.Notations C diffusion coefficient for water in wood with capillary pressure as the driving force, kg/msPa - D diffusion coefficient for water in wood with moisture content as the driving force, kg/ms - F mass flux, kg/m²s - p_c capillary pressure, Pa - p_cf capillary pressure extrapolated linearly to fibre saturation, Pa - T absolute temperature, K - t time, s - x distance ordinale in the direction of flow, m - mass diffusivity, m²/s - density of liquid water, kg/m³ - _g basic density (dry mass/green volume), kg/m³ - _w density of wood substance, kg/m³ - moisture content of wood - _cls moisture content at continuous liquid saturation - _cs moisture content at complete saturation - _f moisture content at fibre saturation  相似文献   

Analysis of shrinkage in wood     

A. J. Hunter 《Wood Science and Technology》1996,30(6):385-395

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A further note on the activation energy of diffusion     

A. J. Hunter 《Wood Science and Technology》1993,28(1):86-88

Summary The activation energy of diffusion can be expressed in terms of thermodynamic quantities such as entropy and enthalpy of sorption. A substantial simplification to such a published expression is presented.  相似文献   

The distinction between average enthalpy and the isosteric heat of water sorbed on wood; and the spatial distribution of the specific enthalpy of the sorbed water     

A. J. Hunter 《Wood Science and Technology》1995,29(5):377-383

Summary It is commonly assumed that specific enthalpy is uniform throughout water sorbed on wood. It is suggested here that this is not the case and that as a result the isosteric heat and the differential heat of wetting are two distinct functions. An analysis is developed which enables the distribution of specific enthalpy within the adsorbed water to be approximated. The results are presented with reference to klinki pine.Symbols a parameter, Eq. (14) - h specific enthalpy of sorbed water, J/kg - h average specific enthalpy of sorbed water, J/kg - h isosteric heat, J/kg - h₁ integral heat of wetting, J/kg - k a constant - l latent heat of vaporization of free water, J/kg - P_s pressure of water vapour at saturation, Pa - q differential heat of wetting, J/kg - R specific gas constant for water, J/kg K - r relative humidity - T temperature, K - enthalpy function defined in Eq. (10), J/kg - moisture content - _p prevailing moisture content The author is grateful to Dr. A. N. Stokes for a substantial simplification of the original derivation of Eq. (13)  相似文献   

On movement of water through wood — The diffusion coefficient     

A. J. Hunter 《Wood Science and Technology》1993,27(6):401-408

Summary It is demonstrated that there can be only one driving potential for the movement of water through wood and this will be a function of wood state. On the assumption that the driving potential is the partial pressure of water vapour, a theoretical expression is derived for the diffusion coefficient. Such expression is fitted to diffusion coefficients for Scots pine and a remarkably good fit is obtained.Symbols a reciprocal mean radius of curvature of a capillary meniscus; also taken to be the radius of the corresponding exposed liquid surface, m - b spacing between flow paths in the cell wall, m - D diffusion coefficient for water in wood with vapour pressure as the driving potential, kg/ms Pa - D_a diffusion coefficient for water vapour through air, kg/ms Pa - D diffusion coefficient for water in wood with the driving potential - D diffusion coefficient for water in wood with the driving potential - D₀ diffusion coefficient for water in wood with vapour pressure as the driving potential, which is associated with leakage paths through the wood, kg/ms Pa - D_f diffusion coefficient for water in wood with vapour pressure as the driving potential, corresponding to fibre saturation and with no leakage paths, kg/ms Pa - D_c diffusion coefficient for water in wood with vapour pressure as the driving potential, which is associated with the constriction of the vapour flow as it approaches the cell wall, kg/ms Pa - D diffusion coefficient for water in wood with moisture content as the driving potential, kg/ms - diffusivity for water vapour in air, m²/s - F flux of water, kg/m² s - p partial pressure of water vapour, Pa - R specific gas constant for water, J/kg K - r fractional relative humidity - T temperature, K - x length coordinate in direction of flow, m - the dimensionless ratio D_f/D_c evaluated at r=1/e - arbitrary driving potential for movement of water in wood - cell spacing in the direction of water flux, m - density of liquid water, kg/m³ - coefficient of surface tension, N/m - arbitrary driving potential for movement of water in wood - fractional moisture content  相似文献   

Mycosphaerella species associated with leaf disease of Eucalyptus globulus in Ethiopia     

Alemu Gezahgne  J. Roux  G. C. Hunter  M. J. Wingfield 《Forest Pathology》2006,36(4):253-263

Eucalyptus spp. are among the most widely planted exotic trees in Ethiopia. Several damaging leaf pathogens are known from Eucalyptus spp. worldwide. Of these, Mycosphaerella spp. are among the most important, causing the disease known as Mycosphaerella leaf disease (MLD). Characteristic symptoms of MLD include leaf spot, premature defoliation, shoot and twig dieback. Recent disease surveys conducted in Ethiopian Eucalyptus plantations have revealed disease symptoms similar to those caused by Mycosphaerella spp. These symptoms were restricted to E. globulus trees growing in several localities in south, south western and western Ethiopia. The aim of this study was to identify the fungi associated with this disease. This was achieved by examining ascospore germination patterns, anamorph associations and sequence data from the Internal Transcribed Spacer (ITS) region of the rRNA operon, for representative isolates. Several different ascospore germination patterns were observed, suggesting that more than one species of Mycosphaerella is responsible for MLD on E. globulus in Ethiopia. Analysis of sequence data showed that three Mycosphaerella spp., M. marksii, M. nubilosa and M. parva were present. This is the first report of these three species from Ethiopia and represents a valuable basis on which to build further studies in the region.  相似文献   

Morphine Synovial Fluid Concentrations After Intravenous Regional Limb Perfusion in Standing Horses          下载免费PDF全文

Barbara G. Hunter DVM  MS  Jill E. Parker VMD  Diplomate ACVS  Rita Wehrman DVM  Bernadette Stang MS  Christopher K. Cebra VMD  MS  Diplomate ACVIM 《Veterinary surgery : VS》2015,44(6):679-686

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Staphylococcus spp., Streptococcus canis,and Arcanobacterium phocae of healthy Canadian farmed mink and mink with pododermatitis     

Gabhan Chalmers  John McLean  D. Bruce Hunter  Marina Brash  Durda Slavic  David L. Pearl  Patrick Boerlin 《Canadian journal of veterinary research》2015,79(2):129-135

Pododermatitis is a disease of concern for mink breeders in Canada and worldwide, as it causes discomfort and lowers the breeding rates on farms affected by the disease. Unfortunately, the etiology and pathogenesis of pododermatitis are still unknown. In this study, we compared Staphylococcus spp. and Streptococcus canis isolates from healthy mink with isolates from animals with pododermatitis on 2 farms in Ontario. Almost all hemolytic Staphylococcus spp. isolated were shown to be Staphylococcus delphini Group A by 16S ribosomal ribonucleic acid (rRNA) sequence analysis and polymerase chain reaction (PCR). Pulsed-field gel electrophoresis (PFGE) did not reveal any S. delphini or S. canis clonal lineages specifically associated with pododermatitis, which suggests that these bacteria do not act as primary pathogens, but does not dismiss their potential roles as opportunistic pathogens. While S. delphini and S. canis were the most prevalent bacterial pathogens in mink pododermatitis, they were also present in samples from healthy mink. Arcanobacterium phocae is occasionally isolated from pododermatitis cases, but is difficult to recover with conventional culture methods due to its slow growth. A quantitative real-time PCR was developed for the detection of A. phocae and was tested on 138 samples of footpad tissues from 14 farms. The bacterium was detected only in pododermatitis-endemic farms in Canada and was at higher concentrations in tissues from infected footpads than in healthy tissues. This finding suggests that A. phocae is involved in the pathogenesis of pododermatitis.  相似文献   

Timing and order of different insecticide classes drive control of Drosophila suzukii; a modeling approach     

Mermer  Serhan  Pfab  Ferdinand  Tait  Gabriella  Isaacs  Rufus  Fanning  Philip D.  Van Timmeren  Steven  Loeb  Gregory M.  Hesler  Stephen P.  Sial  Ashfaq A.  Hunter  Jamal H.  Bal  Harit Kaur  Drummond  Francis  Ballman  Elissa  Collins  Judith  Xue  Lan  Jiang  Duo  Walton  Vaughn M. 《Journal of pest science》2021,94(3):743-755

The spotted-wing drosophila, Drosophila suzukii Matsumura, is an invasive pest causing significant damage to soft skinned fruits. Control of D. suzukii is critical since there is no tolerance for infested fruit in the market. While most insecticides control one or more D. suzukii life-stages (e.g., egg, larvae, and adult), the impact of insecticides that are toxic to immature stages  is unclear on the subsequent generation of a field population. Insecticides were applied at field recommended rates on cherries and blueberries in the laboratory to determine immature D. suzukii mortality. Spinetoram, cyantraniliprole, malathion, methomyl, spinosad, and phosmet resulted in relatively high mortality of all immature life stages. Zeta-cypermethrin, cyclaniliprole, and fenpropathrin resulted in lower mortality of egg and all larval instars. Malathion was also applied to lowbush blueberries with different fruit sizes (small, medium, and large) in the laboratory and there was no statistical difference in mortality rates depending on fruit sizes. Mortality data from the laboratory experiments were used to parameterize a refined D. suzukii population model. The model revealed that the timing and order of different insecticide classes are important to control D. suzukii population. Model runs that included early applications of more effective insecticides resulted in high immature mortality and greater reduction of D. suzukii populations compared to treatments applied later.

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