Modelling the Moisture Induced Risk of Decay for Treated and Untreated Wood Above Ground

Holzforschung ◽  
2000 ◽  
Vol 54 (2) ◽  
pp. 111-118 ◽  
Author(s):  
A. O. Rapp ◽  
R.-D. Peek ◽  
M. Sailer
Keyword(s):  
Moisture Content ◽  
Untreated Wood ◽  
Natural Weathering ◽  
Test Material ◽  
Ground Contact ◽  
Mathematical Relationship ◽  
Durability Prediction ◽  
Laboratory Investigations ◽  
Second Year ◽  
Moisture Vapour

Summary During two years of natural weathering the course of the moisture content of test samples of pine sapwood (Pinus sylvestris L.), Norway spruce (Picea abies L.), oak heartwood (Quercus robur L.) and Douglas fir heartwood (Pseudotsuga menziesii Franco.) was recorded by means of 12,000 individual gravimetric readings. The samples were untreated, treated with a weather protection varnish, or impregnated with melamine resin. The data were evaluated with regard to the number of days per year on which the moisture content of wood exceeded the limit of 25%. From the results of subsequent laboratory investigations into the adsorption of liquid water and moisture vapour desorption using the same test material, it was possible to work out a mathematical relationship (MRI = moisture induced risk index) which correlates closely with the number of days of more than 25% moisture content during the second year of natural weathering. The MRI is proposed as a parameter for the assessment of the protective effect of wood treatments which are intended to reduce moisture content and also for durability prediction of untreated wood in out of ground contact situations.

scholarly journals Effect of Concrete on the pH and Susceptibility of Treated Pine to Decay by Brown-Rot Fungi

Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 41 ◽  
Author(s):  
Darrel Nicholas ◽  
Amy Rowlen ◽  
David Milsted
Keyword(s):  
Treated Wood ◽  
Untreated Wood ◽  
Brown Rot ◽  
Consistent Difference ◽  
Ground Contact ◽  
Decay Fungi ◽  
Brown Rot Fungi ◽  
Organic Systems ◽  
Decay Tests ◽  
Copper Azole

Treated wood timbers employed in ground contact are often installed with a cement collar to firmly fix the structural wood post in place. Few prior studies have determined the effect of concrete on decay efficacy on treated wood, however. Treated wood nominal 4 × 4 posts were installed at four locations, with the upper ground-contact portion of each post encased in concrete, and the samples removed at various times for pH measurements. The wood alkalinity quickly increased at all four sites for the portion of the treated wood in concrete contact compared to the wood in ground contact without concrete. In laboratory decay tests employing three decay fungi, untreated wood which was first exposed or unexposed to concrete had no consistent difference in decay susceptibility. For wood treated with three different commercial copper/organic systems, cement exposure had no effect on wood treated with an amine copper azole system, while treatment with amine copper quat showed a statistically significant fungal efficacy enhancement for cement-exposed samples with both copper-tolerant fungi. Conversely, with a micronized copper azole preservative, cement exposure resulted in reduced fungal efficacy compared to treated samples which were not cement-exposed for all three decay fungi.

scholarly journals Studies into Fungal Decay of Wood In Ground Contact—Part 1: The Influence of Water-Holding Capacity, Moisture Content, and Temperature of Soil Substrates on Fungal Decay of Selected Timbers

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1284
Author(s):  
Brendan Nicholas Marais ◽  
Christian Brischke ◽  
Holger Militz ◽  
Johann Hinrich Peters ◽  
Lena Reinhardt
Keyword(s):  
Moisture Content ◽  
Wood Species ◽  
General Trend ◽  
Wood Decay ◽  
European Beech ◽  
Water Holding Capacity ◽  
Inoculum Potential ◽  
Ground Contact ◽  
Fungal Decay ◽  
Water Holding

This article presents the results from two separate studies investigating the decay of wood in ground contact using adapted versions of laboratory-based terrestrial microcosm (TMC) tests according to CEN/TS 15083-2:2005. The first study (A) sought to isolate the effect of soil water-holding capacity (WHCsoil [%]) and soil moisture content (MCsoil [%WHCsoil]) on the decay of five commercially important wood species; European beech (Fagus sylvatica), English oak heartwood (Quercus robur), Norway spruce (Picea abies), Douglas-fir heartwood (Pseudotsuga menziesii), and Scots pine sapwood (Pinus sylvestris), while keeping soil temperature (Tsoil) constant. Combinations of soil mixtures with WHCsoil of 30%, 60%, and 90%, and MCsoil of 30%, 70%, and 95%WHCsoil were utilized. A general trend showed higher wood decay, measured in oven-dry mass loss (MLwood [%]), for specimens of all species incubated in soils with WHCsoil of 60% and 90% compared to 30%. Furthermore, drier soils (MCsoil of 30 and 70%WHCsoil) showed higher MLwood compared to wetter soils (95%WHCsoil). The second study (B) built on the first’s findings, and sought to isolate the effect of Tsoil and MCsoil on the decay of European beech wood, while keeping WHCsoil constant. The study used constant incubation temperature intervals (Tsoil), 5–40 °C, and alternating intervals of 10/20, 10/30, and 20/30 °C. A general trend showed drier MCsoil (60%WHCsoil), and Tsoil of 20–40 °C, delivered high wood decay (MLwood > 20%). Higher MCsoil (90%WHCsoil) and Tsoil of 5–10 °C, delivered low wood decay (MLwood < 5%). Alternating Tsoil generally delivered less MLwood compared to their mean constant Tsoil counterparts (15, 20, 25 °C). The results suggest that differences in wood species and inoculum potential (WHCsoil) between sites, as well as changes in MCsoil and Tsoil attributed to daily and seasonal weather patterns can influence in-ground wood decay rate.

scholarly journals Control of Insect Pests in The First Alfalfa Crop, 1995

1996 ◽  
Vol 21 (1) ◽  
pp. 193-193
Author(s):  
R. Berberet ◽  
A. Zarrabi ◽  
A. Bisges
Keyword(s):  
Moisture Content ◽  
Dry Matter ◽  
Insect Pests ◽  
Dry Weight ◽  
Chemical Insecticide ◽  
Experiment Station ◽  
Second Year

Abstract Seven chemical insecticide treatments were evaluated for control of AW larvae and aphids in the first crop of a second year stand of ‘Cimarron VR’ alfalfa on the Agronomy Experiment Station, Stillwater, OK. Pretreatment samples indicated a population of 3.1 AW larvae and 20.5 aphids per stem. Insecticides were applied on 1 Apr using flooding nozzles (Spraying Systems Co., TK SS-5) calibrated to deliver 20 gpa at 24 psi when traveling 3 mph. A RCB design was used with 5 X 10 m plots replicated 4 times. Sampling was conducted at 3, 6, 13, and 18 DAT by pulling 25 stems per plot and placing them in standard Berlese funnels to extract insects for counting. Subsamples of aphids were identified on each date to determine the proportions of species present. Dry matter yields were estimated from samples of forage taken from a 1 X 5 m area in each plot. Subsamples were dried for determination of moisture content and yields were calculated on a dry weight/acre basis.

scholarly journals Coating Performance on Exterior Oil-Heat Treated Wood

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 225 ◽  
Author(s):  
Mojgan Nejad ◽  
Mahdi Dadbin ◽  
Paul Cooper
Keyword(s):  
Moisture Content ◽  
Wood Species ◽  
Color Change ◽  
Treated Wood ◽  
Untreated Wood ◽  
Average Moisture Content ◽  
Southern Pine ◽  
Coating Performance ◽  
Spruce Wood ◽  
Heat Treated

Thermal modification and the degree of improved properties from the treatment depend on wood species and treatment parameters. Southern yellow pine and spruce are two wood species commonly used for decking, fences, and siding in North America. This study evaluated coating performance when applied on oil-heat-treated Southern pine and spruce wood samples. Moisture content, color, and gloss changes of samples were analyzed before weathering and then after each month for the first three months and then every six months during 18 months of natural weathering exposure in Toronto, Canada. The results showed that coated heat-treated woods had lower moisture uptake, lower color change, and overall better appearance ranking than coated-untreated wood samples. Coated-spruce wood samples had lower checking and splitting, and in general, much better performance than coated-Southern pine treated samples. Notably, the average moisture content of treated spruce wood samples was significantly lower than that of Southern pine, which explains lower checking and improved coatings’ appearance.

Study on the Improvement of the Permeability of Eucalyptus grandis× Eucalyptus urophylla by Microwave Radiation

2014 ◽  
Vol 556-562 ◽  
pp. 3335-3339
Author(s):  
Jiang Tao ◽  
Kai Yuan Pen ◽  
Gui Long Wu ◽  
Jian Ping Sun ◽  
Xiu Rong Li ◽  
...  
Keyword(s):  
Microwave Radiation ◽  
Eucalyptus Grandis ◽  
Treated Wood ◽  
Untreated Wood ◽  
Microwave Treatment ◽  
Modulus Of Rupture ◽  
Test Material ◽  
Eucalyptus Urophylla ◽  
Eucalyptus Wood ◽  
Weak Points

Low permeability of fast-growing eucalyptus wood restricts its high value in use. In order to explore effective ways of improving the permeability of eucalyptus wood, the method of applying microwave radiation to Eucalyptus urophylla (Eucalyptus grandis×Eucalyptus urophylla) is used to promote its rapid evaporation of water, by which vapor pressure highly increases inside, then vapor bubbles break through the weak points of the wood tissue, as a result, the permeability of the wood is improved. Under the same conditions, wood was tested to achieve the results of water absorption rate (WAR) and water loss rate (WLR) in water sorption measurement and saturated suction drying experiment respectively, after which the permeability, the modulus of rupture (MOR) as well as the modulus of elasticity (MOE) of the test wood are recorded. The results show that the WAR and WLR of the microwave treated wood is higher than that of the untreated wood. Thus it is concluded that microwave radiation can improve the permeability of urophylla wood. But the time of microwave pretreatment has a significant effect on the WAR and WLR, which may be associated with lower microwave power and the variability of the tested material. MOR and MOE of the test material did not change significantly after the microwave treatment.

scholarly journals Flexibility Processes of Pre-service Teachers in Problem Solving with Technology

2020 ◽  
Vol 4 (3) ◽  
pp. 247-255
Author(s):  
Wajeeh Daher ◽  
Ahlam Anabousy
Keyword(s):  
Problem Solving ◽  
Mathematical Problem ◽  
Teacher College ◽  
Creative Problem Solving ◽  
Mathematical Relationship ◽  
Creative Processes ◽  
Research Results ◽  
Creative Problem ◽  
Second Year ◽  
Academic Year

Researchers point at the need to study the creative processes of students in problem solving, as these may indicate how to encourage creative problem solving. The present research attempts to study, based on the heuristic framework of Polya, pre-service teachers' flexibility processes when they solve a mathematical problem with technology.  The research was held in a teacher college, where two second-year classes of 49 mathematics pre-service teachers (24 in the academic year 2017-2018 and 25 in the academic year 2018-2019) participated in the research. The pre-service teachers were requested to solve the halving-the-rectangle problem with technology, specifically with the GeoGebra software. The research results indicated that generally the participants, who performed flexibility processes, used a sequence of creativity processes: conjecturing, specialization, verifying consequences with technology and generalization.  The conjecturing process utilized mathematical relationship or inference from analogy, where the inference from analogy advanced gradually through solution modifications.

Impregnation and Drying Schedule of Eucalyptus Wood

2011 ◽  
Vol 71-78 ◽  
pp. 860-863
Author(s):  
Guo Feng Wu ◽  
Qian Lang ◽  
Shu Ping Song ◽  
Jun Wen Pu
Keyword(s):  
Standard Deviation ◽  
Moisture Content ◽  
Wood Fiber ◽  
Basic Density ◽  
Untreated Wood ◽  
Drying Rate ◽  
Hot Press ◽  
Drying Process ◽  
Eucalyptus Wood ◽  
Wood Composition

The aim of this research was to define a rapid and simple test that would indicate the probable performance of a pretreated wood species in a hot-press drying process and the kiln schedule. The drying rate (mass/time) and the remaining mass of water were measured at different moisture intervals. The moisture of timber decreased rapidly and the drying rate was 3.7% per day in the early five days. The timbers were B grade after drying used the hot-press drying kiln in 16 days. The moisture content of timber reached 9.20% after the drying process with the standard deviation of 0.92%. The gradient of the moisture content was 3.40%. The moisture content standard deviation in the thickness of timber was 2.70% and the residual stress was 1.38%. The mechanical properties of impregnation wood improve significantly compared to the untreated wood. The basic density of impregnation wood improved by 17.1%, the over-dried density increased to 0.55 g·cm-3 from 0.49 g·cm-3. The scanning electron microscopy explained the wood modifier has been permeated into the wood fiber which reacted with the wood composition.

Moisture adsorption characteristics of copper-ethanolamine (Cu-EA) treated Southern yellow pine (Pinus spp.)

Holzforschung ◽  
2004 ◽  
Vol 58 (1) ◽  
pp. 32-38 ◽  
Author(s):  
J. Cao ◽  
D. P. Kamdem
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Moisture Content ◽  
Treated Wood ◽  
Untreated Wood ◽  
Moisture Adsorption ◽  
Adsorption Sites ◽  
Yellow Pine ◽  
Pinus Spp ◽  
Southern Yellow Pine

Abstract Moisture adsorption isotherms were determined for untreated and copper-ethanolamine (Cu-EA) treated wood at different copper retention levels. The Cu-EA treatment reduces the water vapor accessibility in wood because copper has occupied some of the adsorption sites for moisture during the treatment. The percentage of adsorption sites occupied by copper was evaluated by M t/M u, which is the ratio of equilibrium moisture content for treated wood to untreated wood. The results show that, within the copper retention range used in this study, the M t/M u value decreases linearly at lower temperatures (4 and 15 °C) or logarithmically at higher temperatures (30 and 40 °C) with the increase of copper retention, suggesting that the percentage of adsorption sites occupied by copper (P) increases linearly or logarithmically with the copper retention in Cu-EA treated wood. P decreases with the increase of relative humidity. The reason is that more adsorption sites become available for moisture at higher relative humidity. It has also been found that the influence of Cu-EA treatment on hydrated water (M h) is more significant than that on dissolved water (M s).

Seasonal changes in mite (Acari) and fungal populations in aerated and unaerated wheat stored for three years

1980 ◽  
Vol 70 (4) ◽  
pp. 537-548 ◽  
Author(s):  
E. T. Hurlock ◽  
D. M. Armitage ◽  
B. E. Llewellin
Keyword(s):  
Moisture Content ◽  
Storage Period ◽  
Physical Conditions ◽  
Acarus Siro ◽  
Aspergillus Glaucus ◽  
Wallemia Sebi ◽  
Fungal Populations ◽  
Second Year ◽  
One Year ◽  
Cheyletus Eruditus

AbstractIn experiments at Slough, southern England, one hundred tonnes of wheat at about 14% moisture content were divided between six similar metal bins, three of which were aerated during the winter. Observations were made on the mite and fungal populations and physical conditions for an uninterrupted storage period of three years. During the winter, the wheat in the aerated bins was 2–4°C cooler than that in the unaerated bins and it always had a moisture content 0·5–1% higher, except at the surface where it was usually drier. Aeration appeared to delay the increase of Acarus siro L. and Lepidoglyphus destructor (Schr.) for 4–6 months after harvest, but few individuals survived into the second year of storage in any bin. Cheyletus eruditus (Schr.) and Tydeus interruptus Thor were present after one year and were most numerous in the aerated bins. The distribution within the bins of the different species of mites varied with season. A greater increase in storage fungi occurred in the aerated bins than the unaerated. Members of the Aspergillus glaucus and A. restrictus groups, Penicillium spp. and Wallemia sebi were the commonest fungi.

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