Influence of specimen size during accelerated weathering of wood-based structural panels     

Daniel Way  Frederick A. Kamke 《Wood material science & engineering》2020,15(1):17-29

ABSTRACT

Wood structural panels are commonly subjected to short-term accelerated weathering (AW) procedures to determine relative moisture durability for quality control and product development purposes. The panel edges contribute heavily to moisture uptake since edges represent the least resistant pathway for moisture intrusion. In full-size panels, the edge area to total surface area ratio is small, and moisture intrusion is primarily limited to panel faces. When small specimens are used, such as those in AW procedures, the ratio of edge area to total surface area increases and moisture intrusion at the edges may dominate, which is referred to as the edge effect. The purpose of this study was to determine if physical and mechanical properties of oriented strand board (OSB) and plywood after AW are influenced by specimen size. Specimen width was varied while thickness and length remained constant to understand if edge effects were present in small specimens with different edge area to total surface area ratios. Three AW procedures were evaluated to determine if the effect of specimen size depends on weathering method. No clear effect of specimen size on physical and mechanical properties of either composite type was found. Differences in flexural properties between specimen widths were observed for unweathered OSB, but similar property retention between specimen widths after AW indicated the same trend as the unweathered control. Plywood results were influenced by natural defects, resulting in high variability and absence of statistically significant differences. Lateral nail resistance connection properties of both OSB and plywood were highly variable for all treatment groups and were unaffected by weathering.  相似文献   

Bentazon leaching in four Illinois soils.     

E W Stoller  L M Way  L C Haderlie  F W Slife 《Journal of agricultural and food chemistry》1975,23(4):682-684

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Carbaryl as a Fruit Thinning Agent     

D.W. Way 《The Journal of Horticultural Science and Biotechnology》2013,88(4):355-365

The results are presented of fruit thinning studies carried out over several years with the apple varieties Laxton’s Superb and Worcester Pearmain.

The thinning activity of carbaryl was negligible at 0·0028% a.i. but increased rapidly over the range 0·0083% to 0·075%. Comparatively little additional thinning resulted from a further increase in concentration.

In Worcester Pearmain thinning was stimulated by applications of carbaryl over a 4–5 week period from petal fall, the cessation of thinning activity coinciding with the end of the main period of natural fruitlet shedding. The intensity of thinning was greatest at petal fall and declined with delay in application. This decline was not continuous but showed two intervals of 7 to 13 days duration during which the intensity of thinning remained relatively constant. Up to 12 days elapsed between application and the commencement of induced fruitlet shedding.

Carbaryl was found to thin within, rather than between, fruitlet clusters, and to stimulate the abscission of lateral fruitlets more than terminal ones.

The growth of young fruitlets was retarded for a short period following the application of carbaryl, but as a result of thinning the size of mature fruit was increased. In the year after treatment increased blossoming and cropping was most marked with biennial trees of Laxton’s Superb. With regularly cropping trees of Worcester Pearmain, although thinning induced a moderate increase in subsequent blossoming, no residual effects on cropping were detected.  相似文献   

The effect of carbon and nutrient loading during nursery culture on the growth of black spruce seedlings: a six-year field study     

Danielle A. Way  Seth D. Seegobin  Rowan F. Sage 《New Forests》2007,34(3):307-312

We tested the effects of exponential nutrient loading and springtime carbon loading during nursery culture on the field performance of black spruce (Picea mariana (Mill.) B.S.P.). Seedlings were grown from seed with a conventional, fixed dose fertilizer (10 mg N seedling⁻¹) or an exponential nutrient loading regime (75 mg N seedling⁻¹). The following spring, seedlings were exposed for two weeks to either ambient (370 ppm) or elevated levels of CO₂ (800 ppm) and then planted in the field; seedling growth was followed for the next six years. Exponential nutrient loading increased seedling height, stem diameter and leader growth, with the largest increases in height and leader length occurring in the first three years after outplanting. Carbon loading increased seedling height and leader length, but only in seedlings that had been exponentially nutrient loaded. A combination of carbon and nutrient loading increased shoot height 26%, stem diameter 37% and leader length 40% over trees that received neither treatment. These results demonstrate that the growth enhancement seen under exponential nutrient loading is maintained under field conditions for at least six years. Carbon loading just before outplanting was a useful supplement to nutrient loading, but was ineffective in the absence of nutrient loading.  相似文献   

The first report of viral haemorrhagic septicaemia in farmed rainbow trout, Oncorhynchus mykiss (Walbaum), in the United Kingdom     

Stone DM  Ferguson HW  Tyson PA  Savage J  Wood G  Dodge MJ  Woolford G  Dixon PF  Feist SW  Way K 《Journal of fish diseases》2008,31(10):775-784

Viral haemorrhagic septicaemia (VHS) was diagnosed in rainbow trout in the UK in May 2006. VHS virus (VHSV) was isolated from fingerlings showing typical histopathological lesions at a single rainbow trout farm site experiencing high mortality. The virus was confirmed as VHSV by serological and molecular biological tests. Phylogenetic analysis based on the complete glycoprotein gene sequence revealed that the isolate was closely related (99% nucleotide identity) to several Danish isolates from 1991 to 2000 and was assigned to VHSV genogroup Ia. The pathogenicity of the isolate was determined in infection experiments using rainbow trout fry. Following waterborne challenge, cumulative mortalities reached 96.67-100% by 12 days post-infection. This represents the first isolation of a pathogenic freshwater VHSV in the UK.  相似文献   

Effects of MCPA on Lettuce pro-inoculated with Lettuce Mosaic Virus     

J. M. Way 《Plant pathology》1968,17(2):75-77

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Large-scale mitochondrial DNA deletions in weak goslings     

Wang CM  Way TD  Chen LR  Chung YC  Hu CL  Nien PC  Yen NT  Jea YS  Kao JY 《British poultry science》2011,52(1):48-51

1. Evidence has accumulated in mammals to support the idea that mitochondrial DNA (mtDNA) deletions and mutations might contribute to ageing and reproductive failure. White Roman geese were monitored to evaluate the effect of large-scale deletions of mtDNA in an avian species. 2. A total of 340 samples from 114 dead embryos, 111 weak goslings, and 115 normal goslings were used in this experiment. The regions of these two large-scale mtDNA deletions, ΔmtDNA6829 and ΔmtDNA6992, were between the COI and ND5 genes. A 3·6% (4 out of 111) positive sample was detected in the weak goslings. In contrast, no large-scale mitochondrial DNA deletions were detected in either the dead embryos (0 out of 114) or the normal goslings (0 out of 115). 3. Large-scale mtDNA deletions may be a factor causing weak goslings.  相似文献   

Tree phenology responses to warming: spring forward, fall back?     

Way DA 《Tree physiology》2011,31(5):469-471

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增加城市绿量的好方法--垂直绿化     

武新  张立新  尤长军 《辽宁农业职业技术学院学报》2002,4(3):37-38

垂直绿化做为一种立体绿化形式,占地少,绿化效果好,是增加城市绿量和形成城市美好景观的好方法.本文从垂直绿化的特点、垂直绿化的材料、垂直绿化的形式三方面详尽阐述了在城市中发展垂直绿化的必要性.  相似文献   

Observations on the Field Performance of Heat-Treated Strawberry Clones     

D. W. Way 《The Journal of Horticultural Science and Biotechnology》2013,88(2):167-174

The growth and cropping of two virus-infected strawberry varieties was compared with that of clones the virus content of which had been reduced by heat therapy.

The heat-treated clones of both Cambridge Favourite and Early Cambridge were considerably more vigorous, bearing more crowns than their untreated counterparts. In the first year after planting, both clones of each variety produced similar total yields, but the heat-treated clones produced a higher percentage of large fruit. Plants of the heat-treated clone of Cambridge Favourite flowered and ripened their fruit later than plants of the untreated clone in the second year, but gave a greater yield. However, the two clones of Early Cambridge gave similar yields, the increased potential of the heat-treated clone provided by a greater number of crowns being offset by reduced inflorescence formation.

In order to establish whether reduction of vigour would lessen the tendency of some heat-treated clones to form barren crowns, spring planting was compared with autumn planting. Spring planting, which reduced plant size and yield of both varieties in the first season but had less effect on size and none on yield in the second season, failed to check partial barrenness in the heat-treated clone of Early Cambridge.

At the end of the first growing season the heat-treated clones of both varieties showed a greater incidence of Verticillium wilt than the untreated clones but this difference was not maintained in the second year.  相似文献