Technical Note: Effect of Soil on the pH of Treated Wood in Ground Contact

The pH of treated wood in ground contact will influence the type and activity of decay and nondecay microorganisms present as well as the solubility and leaching of metallic biocides. To determine the soil effect on the pH of treated wood in ground contact, southern pine sapwood samples commercially treated with five copper-based preservatives along with untreated pine were placed in pots filled with five different soils. The pH of the wood samples after a 12-wk exposure to basic soils increased, as anticipated. However, the pH of wood in acidic soils was more complex than expected with the treated wood pH always greater than soil pH. Two possible chemical mechanisms to explain the nonintuitive results for treated wood in acidic soils are given

Efficacy of a Series of Alkylammonium Compounds Against Wood Decay Fungi and Termites

The efficacy of four alkylammonium compounds was determined for eight common wood decay fungi and Reticulitermes sp. termites in laboratory tests. All of the compounds tested were found to be effective against both fungi and termites, but only dialkyldimethylammonium chloride was fully effective against all of the brown- and white-rot fungi tested in this study. On the basis of this and other studies, it is concluded that some of the alkylammonium compounds are satisfactory wood preservatives for the treatment of softwoods used in out-of-ground contact applications. More extensive field studies will be required before their potential as ground contact wood preservatives can be determined

A critical review of methods for dimensionally stabilizing wood by crosslinking

One of the major disadvantages of wood is that it swells and shrinks when water is adsorbed or desorbed below the fiber saturation point. This property causes numerous problems when wood is used as a structural material. Consequently, a considerable amount of research has been conducted on this problem, but has resulted in only a ]invited degree of success to date. There are several approaches to this problem (1) but this paper will be limited to a discussion of crosslinking by chemical methods. The discussion will include cotton as well as wood, because a great deal of research has been conducted on crosslinking cotton. This information will be of great value in future work on wood. A major emphasis will be placed on reaction mechanisms for the various compounds

Synergistic Wood Preservatives: Terrestrial Microcosms (TMCs) and Field Exposure Efficacy Studies of the Synergistic Copper: Pyrithione Mixture

On the basis of short-term laboratory tests using various wood decay fungi, we previously found that the mixture of copper (II) and sodium pyrithione is highly synergistic. In this study we examined the efficacy of this mixture in protecting wood using terrestrial microcosms (TMCs) with three different Swedish soils, and field stake (ground contact) tests in two different locations in Mississippi. After 12 months of exposure in TMCs, the copper: pyrithione mixture was found to be more effective than either component alone, with only slight degradation due to tunneling bacteria in a compost soil TMC. The field stake test, after 6 years of exposure, showed that a mixture of 0.31 pcf or greater copper (as CuO) and 0.063 pcf or greater pyrithione (as the sodium salt) was approximately as effective as about 0.35 pcf CCA in preventing fungal and termite degradation

Rapid Assessment of Southern Pine Decayed by G. Trabeum by Near Infrared Spectra Collected from the Radial Surface

The use of near infrared (NIR) spectroscopy for predicting levels of degradation in southern pine (Pinus spp.) by Gloeophyllum trabeum for periods over 1-8 da was investigated. NIR spectra collected from the center of the radial face of each sample after laboratory soil block decay tests were used to develop calibrations. Calibrations were developed for mass loss, compression strength, and exposure period using data measured from prior methods and untreated and mathematically treated (multiplicative scatter correction and first and second derivative) NIR spectra from various ranges of wavelengths by partial least squares regression. Strong relationships were derived from the calibrations with the strongest R2 values of 0.97 (exposure period), 0.94 (compression strength), and 0.91 (mass loss). Calibrations for exposure period showed the strongest statistics for predicting wood decay of the validation test set (R2 = 0.92; RPDp [ratio of the standard deviation of the measured data to the standard error of prediction] = 3.95 [first derivative, 1100-2250 nm]), while predictions for mass loss of the decayed samples resulted in R2 = 0.86 and an RPDp = 3.17 (multiplicative scatter correction, 1100-2500 nm), and the strongest compression strength prediction resulted in R2 = 0.76 and an RPDp = 2.50 (second derivative, 1100-2500 nm). These results suggest that NIR spectroscopy can adequately predict wood decay from spectra collected from the radial face of southern pine

Assessment of physical, mechanical, and biological properties of bamboo plastic composite made with polylactic acid

The effects of different mixing, bamboo mesh size and heat treatment on the physical and mechanical properties and biodegradability of a polylactic acid (PLA) composite were determined. The results indicated that this composite exhibited high strength in all mechanical properties examined, except hardness using the pure polymer (PLA). The mesh size of the bamboo flour and heat treatment had considerable effects on all tests expect the decay resistance. The water absorbance and thickness swelling of the PLA composite was reduced to nearly zero after 3000 hours immersion in water. Moreover, the fungal decay test results demonstrated that PLA was highly resistant to both Basidiomycetes and Ascomycetes fungi. The brown rot fungi, however, produced an extensive mass loss in the composite composed of different levels of bamboo flour

Development of a Low-Resource Combined Gamma-Ray and Neutron Spectrometer for Planetary Science

Planetary neutron and gamma-ray spectroscopy (NGRS) has become a standard technique to measure distinctive geochemical composition and volatile abundance signatures for key elements relevant to planetary structure and evolution. Previous NGRS measurements have led to the discovery of the concentration of many elements including hydrogen on the Moon, Mars, Mercury, and the asteroids Eros, Vesta, and Ceres, but by utilizing separate NGRS. We have developed the Elpasolite Planetary Ice and Composition Spectrometer (EPICS) instrument, an innovative and combined NGRS with low resource requirements. EPICS incorporates elpasolite scintillator read out by silicon photomultipliers (SiPMs) to provide significant reduction in size, weight, and power, while achieving excellent neutron detection sensitivity and gamma-ray energy resolution as good as 2.9% full-width half-maximum at 662 keV. EPICS is ideally suited to resource constrained missions and is applicable to numerous targets such as the Moon, Mars, and small planetary bodies. An overview of the EPICS instrument and its simulated performance on a few notional missions is presented. We have integrated and done performance testing of a prototype of the EPICS instrument, including optimization of an amplification and summing circuit for a 64-element SiPM array that preserves pulse shape discrimination capability, which will be summarized

Influence of relative humidity and temperature on cultivation of pleurotus species

Fungi exhibit different behavior under different conditions and react to light, temperature, moisture content etc. The objective of  this study was to evaluate the degradation capability of three common white rot fungi, namely: Pleurotus ostreatus, P. pulmonarius, and Lentinus sajor-caju. The respective fungi were cultivated on rice straw under three different environmental conditions for 90 days. The fungi were collected, pure cultured, DNA extracted, and sequenced by ITS regions. The highest consumption of substrate occurred under the Cellar (dark) exposure condition with P. pulmonarius producing the least mass loss. The least amount of degradation occurred under the Air (daylight) condition for all of the fungi with the exception of P. pulmonarius. Exposure to light promoted the formation of fruiting bodies

Monitoring the cell wall characteristics of degraded beech wood by white-rot fungi: Anatomical, chemical, and photochemical study

Meticulous chemical analysis of decaying xylem and linking it to corresponding anatomical modification at the cellular level can improve our understanding of the decay process. The aim of this study was to monitor the histological, chemical, photochemical, and progression of wood degradation by two white-rot fungi at different intervals. Oriental beech wood (Fagus orientalis) blocks were exposed to Pleurotus ostreatus and Trametes versicolor to investigate the degradation capabilities of these two fungi. Light microscopy was used to study the decay patterns in wood. Decayed wood samples were also analyzed to determine lignin, cellulose and sugar contents and also evaluated at two week intervals by FT-IR spectroscopy to study chemical alterations. According to chemical analyses lignin is the most degraded polymer followed by cellulose and hemicelluloses for both white rot fungi. However, both test fungi tended to consume lignin more than cellulose. FT-IR spectra changes for  lignin and carbohydrates in beech wood supported chemical alteration and indicated that both fungi decay wood in a simultaneous pattern.&nbsp

A systematic approach to designing reliable VV optimization methodology: Assessment of internal validity of echocardiographic, electrocardiographic and haemodynamic optimization of cardiac resynchronization therapy

AbstractBackgroundIn atrial fibrillation (AF), VV optimization of biventricular pacemakers can be examined in isolation. We used this approach to evaluate internal validity of three VV optimization methods by three criteria.Methods and resultsTwenty patients (16 men, age 75±7) in AF were optimized, at two paced heart rates, by LVOT VTI (flow), non-invasive arterial pressure, and ECG (minimizing QRS duration). Each optimization method was evaluated for: singularity (unique peak of function), reproducibility of optimum, and biological plausibility of the distribution of optima.The reproducibility (standard deviation of the difference, SDD) of the optimal VV delay was 10ms for pressure, versus 8ms (p=ns) for QRS and 34ms (p<0.01) for flow.Singularity of optimum was 85% for pressure, 63% for ECG and 45% for flow (Chi2=10.9, p<0.005).The distribution of pressure optima was biologically plausible, with 80% LV pre-excited (p=0.007). The distributions of ECG (55% LV pre-excitation) and flow (45% LV pre-excitation) optima were no different to random (p=ns).The pressure-derived optimal VV delay is unaffected by the paced rate: SDD between slow and fast heart rate is 9ms, no different from the reproducibility SDD at both heart rates.ConclusionsUsing non-invasive arterial pressure, VV delay optimization by parabolic fitting is achievable with good precision, satisfying all 3 criteria of internal validity. VV optimum is unaffected by heart rate. Neither QRS minimization nor LVOT VTI satisfy all validity criteria, and therefore seem weaker candidate modalities for VV optimization. AF, unlinking interventricular from atrioventricular delay, uniquely exposes resynchronization concepts to experimental scrutiny