663 research outputs found

    Using Acoustic Analysis To Presort Warp-Prone Ponderosa Pine 2 By 4s Before Kiln-Drying

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    This study evaluated the potential of acoustic analysis as presorting criteria to identify warp-prone boards before kiln-drying. Dimension lumber, 38 by 89 mm (nominal 2 by 4 in.) and 2.44 m (8 ft) long, sawn from open-grown small-diameter ponderosa pine trees, was acoustically tested lengthwise at green condition. Three acoustic properties (acoustic speed, rate of wave attenuation, and acoustic modulus of elasticity (MOE)) were then determined through waveform analysis. Boards were then kiln-dried, and warp was measured immediately after drying and after equilibrating to about 13% equilibrium moisture content. Crook and bow measured after drying decreased as acoustic speed and acoustic MOE of green boards increased and rate of wave attenuation of green boards decreased. Twist was found to have no relationship with any acoustic properties of green 2 by 4s. The results also show a statistically significant correlation between acoustic properties of green 2 by 4s and the grade loss caused by exceeding warp limits. As the number of Structural Light Framing grade losses increased, the acoustic speed and acoustic MOE decreased significantly, whereas rate of wave attenuation increased significantly. However, no relationship was found between green board density and warp and grades lost

    Acoustic Tomography for Decay Detection in Black Cherry Trees

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    This study investigated the potential of using acoustic tomography for detecting internal decay in high-value hardwood trees in the forest. Twelve black cherry (Prunus serotina) trees that had a wide range of physical characteristics were tested in a stand of second-growth hardwoods in Kane, PA, using a PiCUS® Sonic Tomograph tool. The trees were felled after the field test and a disc from each sampling height was cut and subjected to laboratory evaluations. It was found that acoustic tomography underestimates heartwood decay when it is the major structural defect in the trees. However, when an internal crack is present in the tree trunk, the acoustic tomography tends to overestimate the size of the defects. In the presence of ring shake in the cross-section, the acoustic shadows resemble the influence of both extensive heartwood decay and lateral cracks. These findings highlight the importance of determining the nature of structural defects when assessing hardwood trees using the acoustic tomography technique. Results from this study offer insights that may be used to improve the interpretation algorithm embedded in the tomography software

    Potential novel bZIP-like gene for resistance to Erysiphe necator identified in Chinese wild Vitis pseudoreticulata

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    In this study, a novel bZIP-like gene was isolated from Chinese wild Vitis pseudoreticulata W. T. acc. Baihe-35-1. The full-length complementary deoxyribonucleic acid (cDNA) sequence of the gene was 1583 bp including 159 bp 5’ untranslated region (UTR), 365 bp 3’ UTR and a 1083 bp ORF which encodes a polypeptide of 360 amino acids with a molecular weight of 38.662 kDa. The deduced amino acid sequence shares an overall 46 to 69.8% sequence similarity with bZIP from other plants. Therefore, we designated this gene as V. pseudoreticulata bZIP (VpbZIP-like). The expression of VpbZIP-like was induced 12 h post inoculation (hpi) by Erysiphe necator, but transiently decreased, then increased in these two genotypes and its expression was lower in highly resistant genotype Baihe-35-1 than in susceptible genotype Hunan-1 at 24, 48 and 72 hpi. We further tested whether the expression was also a response to plant signaling molecules. Results indicate that the susceptible genotype Hunan-1 showed higher expression of VpbZIP-like than the highly resistant genotype Baihe-35-1 after exogenous application of methyl jasmonate (MeJA), salicylic acid (SA) and ethephon (Eth). Moreover, tissue specific expression pattern of VpbZIP-like was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Results reveal that it was in lower lever in flower than in leaf, stem, tendril and fruit. The CDS of VpbZIP-like was inserted into the prokaryotic expression construct pGEX-4T-1, and then transformed into Escherichia coli BL21-code induced by isopropyl-b-D-thiogalactopyranoside (IPTG) which resulted in the production of a Mr. 64 kDa of GST- VpbZIP-like fusion protein displayed in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).Key words: Chinese wild Vitis, bZIP, gene expression, signaling molecules, fusion protein expression

    Isolation and characterization of cDNA encoding stilbene synthases from Chinese wild Vitis pseudoreticulata

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    mRNA differential display was employed to study powdery mildew disease resistance gene expression in Chinese wild Vitis pseudoreticulata 'Baihe-35-1' inoculated with Erysiphe necator (syn. Uncinula necator) under natural field conditions. A cDNA fragment T11AC/B0320-723 showing homology to stilbene synthase (STS) gene expressed more strongly at 1, 3, 5, 7 and 9 days after inoculation of leaves than in controls was found. The full cDNA length was cloned by rapid amplification of cDNA ends (RACE). Sequencing of the full length cDNA revealed cDNA sequences, sized 1288, 1411, 1468, 1492, 1506 and 1556 base pairs encoding 6 homologous polypeptides with 392 amino acid residues each, that were designated as VpSTS1, VpSTS2, VpSTS3, VpSTS4, VpSTS5 and VpSTS6 respectively. The deduced amino acid sequences shared identity of 65 %, 77 % and more than 94 % with Pinus strobus STS, Vitis vinifera chalcone synthase (CHS), and Vitis riparia, Vitis labrusca, Parthenocissus henryana, Cissus rhombifolia, Parthenocissus quinquefolia and Vitis vinifera STS, respectively.

    Empirical Likelihood With Applications

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    Ph.DDOCTOR OF PHILOSOPH

    Nondestructive assessment of wood members in a viewing tower in Potawatomi State Park, Door County, Wisconsin, US

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    The State of Wisconsin’s Department of Natural Resources is responsible for operating one of the largest state park systems in the United States. Potawatomi State Park, located on the Door County peninsula, consists of about 1,200 acres of flat to gently rolling upland terrain bordered by steep slopes and rugged limestone cliffs along Lake Michigan’s shoreline. A 75-ft observation tower sits atop a 150-ft bluff overlooking Lake Michigan. The USDA Forest Service, Forest Products Laboratory, was asked to conduct an assessment of the main support timbers of the tower. This report summarizes the results obtained from the inspection and assessment. It includes a brief summary of the nondestructive testing techniques that were used, observations, data from tests conducted on the timbers, and recommendations

    Acoustic Evaluation of Wood Quality in Standing Trees. Part I. Acoustic Wave Behavior

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    Acoustic wave velocities in standing trees of five softwood species were measured by the time-of-flight (TOF) method. Tree velocities were compared with acoustic velocities measured in corresponding butt logs through a resonance acoustic method. The experimental data showed a skewed relationship between tree and log acoustic measurements. For most trees tested, observed tree velocities were significantly higher than log velocities. The results indicate that time-of-flight measurement in standing trees is likely dominated by dilatational or quasi-dilatational waves rather than one-dimensional plane waves. To make appropriate adjustments of observed tree velocities, two analytical models were developed for the species evaluated. Both the multivariate regression model and dilatational wave model were effective in eliminating deviation between tree and log velocity and reducing variability in velocity prediction

    Analysis of RSA based on Quantitating Key Security Strength

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    AbstractRSA is an asymmetric crypto algorithm which is applied widely in the information security of E-Commerce and Internet-Bank. Its security has been withstanding tests since several decades ago. But the key security isn’t equal to that of algorithm, which is often neglected by most of users and scholars. As to most constructions, they lack definite recognition to the safety of the RSA key. As a result, even some strong crypto-algorithms used it still meets the security predicament. In this paper, start with the known plaintext attack to RSA public key crypto scheme, we pioneer the mechanism of quantitation of the RSA key security strength, the concept of key security coefficient, the evaluation model of security coefficient and the algorithm to extract security strength. Further more, an innovative method of generating secure keys is proposed. After some experimentations, the security performance of key and distribution of secure key-amount, and their key security coefficient are surveyed and analyzed in detail. The theoretic analysis and statistics demonstrate that our mechanism could elevate security of RSA in effect

    Nutrient inversion and hyperspectral feature extraction of sea rice at diff erent growth stages

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    Nitrogen is a large amount of essential elements for the growth and development of sea rice. Monitoring the nitrogen nutrition status of sea rice timely and accurately, and rational fertilization of sea rice is of great signifi cance for increasing yield, optimizing quality and reducing water pollution. The remote sensing diagnosis technology of sea rice nutrition has the characteristics of simple, non_x005fdestructive and rapid, and has been widely studied and applied by experts in various countries. In this experiment, the sea red rice varieties were taken as an example. Through field experiment, the leaves of sea rice in four growth stages were collected by using chlorophyll analyzer and near infrared spectrometer, and the chlorophyll value and spectral refl ectance of sea rice leaves were determined. The results showed that the spectral refl ectance of sea rice leaves in diff erent growth stages had obvious changes. The sensitive band of sea rice leaves was further found by combining the spectral curve, which laid the foundation for the future nitrogen nutrition diagnosis of sea rice
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