Experimental study of moisture-driven distortion and fracture in solid wood

DEFF Research Database (Denmark)

Larsen, Finn; Ormarsson, Sigurdur; Olesen, John Forbes

2010-01-01

Moisture-induced fracture and lack of shape stability in solid wood products are well known problems to the saw-milling and building industries. Cracks that initiate during the drying process may cause severe material losses and the building industry may be forced to use alternative building....... An experimental study has been performed to reveal the cracking behaviour of Norway spruce during drying from green moisture content down to equilibrium moisture content (EMC) at a temperature of 22-24°C and a RH of 64%. The moisture related strains and crack widths were measured with a digital image correlation...... than the thinner ones (15 mm) and the crack patterns developed differently. For the thicker discs the early cracks which may partly be caused by the moisture gradient in the longitudinal direction of the log, closed and became invisible later during the drying process. This indicates that sealing...

Preliminary evaluation of production and characterization of wood vinegar from rubberwood

Directory of Open Access Journals (Sweden)

Juraivan Ratanapisit

2009-08-01

Full Text Available This study deals with a slow pyrolysis of rubberwood in a furnace at an atmospheric pressure to produce pyroligneous liquid or wood vinegar. Pyroligneous liquids produced were separated into two fractions based on temperatures in a furnace. The yields of wood vinegar were quantified. Also pH, SG and boiling ranges were determined. The optimum condition of pyrolysis was obtained at the heating rate of 1.4oC/min to the final temperature at 550oC/min with a yield of 27.45%. The pH and specific gravity were attained at about 2.9-3.83 and 1.009-1.027, respectively, depend on process conditions. Also the boiling ranges of rubberwood vinegar approximately were 96-108oC based on the ASTM-D86 method. However, no significantlychanges were seen in the pH, specific gravity and boiling ranges of rubberwood vinegar regarding to hearting rates. For characterization, wood vinegar was fractionated by a distillation into three fractions. Both crude and distilled wood vinegars were analyzed by gas chromatography-mass spectroscopy and gas chromatography. Results showed that the wood vinegar is mainly composed of acetic acid. Also the rubberwood pyrolysis yields high methanol content compared to other woods.

Tracer Methods for Characterizing Fracture Creation in Engineered Geothermal Systems

Energy Technology Data Exchange (ETDEWEB)

Rose, Peter [Energy & Geoscience Institute at the University of Utah, Salt Lake City, UT (United States); Harris, Joel [Univ. of Utah, Salt Lake City, UT (United States)

2014-05-08

The aim of this proposal is to develop, through novel high-temperature-tracing approaches, three technologies for characterizing fracture creation within Engineered Geothermal Systems (EGS). The objective of a first task is to identify, develop and demonstrate adsorbing tracers for characterizing interwell reservoir-rock surface areas and fracture spacing. The objective of a second task is to develop and demonstrate a methodology for measuring fracture surface areas adjacent to single wells. The objective of a third task is to design, fabricate and test an instrument that makes use of tracers for measuring fluid flow between newly created fractures and wellbores. In one method of deployment, it will be used to identify qualitatively which fractures were activated during a hydraulic stimulation experiment. In a second method of deployment, it will serve to measure quantitatively the rate of fluid flowing from one or more activated fracture during a production test following a hydraulic stimulation.

Statistical analysis of surface lineaments and fractures for characterizing naturally fractured reservoirs

Energy Technology Data Exchange (ETDEWEB)

Guo, Genliang; George, S.A.; Lindsey, R.P.

1997-08-01

Thirty-six sets of surface lineaments and fractures mapped from satellite images and/or aerial photos from parts of the Mid-continent and Colorado Plateau regions were collected, digitized, and statistically analyzed in order to obtain the probability distribution functions of natural fractures for characterizing naturally fractured reservoirs. The orientations and lengths of the surface linear features were calculated using the digitized coordinates of the two end points of each individual linear feature. The spacing data of the surface linear features within an individual set were, obtained using a new analytical sampling technique. Statistical analyses were then performed to find the best-fit probability distribution functions for the orientation, length, and spacing of each data set. Twenty-five hypothesized probability distribution functions were used to fit each data set. A chi-square goodness-of-fit test was used to rank the significance of each fit. A distribution which provides the lowest chi-square goodness-of-fit value was considered the best-fit distribution. The orientations of surface linear features were best-fitted by triangular, normal, or logistic distributions; the lengths were best-fitted by PearsonVI, PearsonV, lognormal2, or extreme-value distributions; and the spacing data were best-fitted by lognormal2, PearsonVI, or lognormal distributions. These probability functions can be used to stochastically characterize naturally fractured reservoirs.

Characterization of fracture toughness of epoxy resin after hygrothermal aging

KAUST Repository

Quispe, Gustavo Q.

2013-07-01

Characterization of fracture toughness of epoxy resin after hygrothermal ageing Gustavo Quino Quispe The aim of this work is to characterize the e ects of hygrothermal aging in the plain strain fracture toughness of the epoxy system composed by cycloaliphatic epoxy resin and diglycidyl ether of bisphenol-A (DGEBA). For this, after having been under hygrothermal aging in a climatic chamber, epoxy samples were studied using ASTM D5045 fracture toughness test, and micrography and roughness measurements of the fracture surface. It is reported a rapid decrease of GIc and KIc during the rst 2 days. Moreover, a numerical model [13] was used to simulate and see with more detail the water absorption in the aged samples. From that, it was observed the heterogeneous distribution of water. Accordingly, it was proposed that the results should be correlated with the water content at the vicinity of the crack tip. Consequently, it was possible to obtain, by quasi-static simulations, the ideal load-displacement curves of crack propagation in the heterogeneous samples. Finally, another contribution of this work is the study of the fracture surface, that gives a clue of the relationship among the fracture energy, the appearance of microcracks in the fracture surface, and the roughness (Ra).

Anisotropic characterization of rock fracture surfaces subjected to profile analysis

International Nuclear Information System (INIS)

Zhou, H.W.; Xie, H.

2004-01-01

The mechanical parameters of a rock fracture are dependent on its surface roughness anisotropy. In this Letter, we show how quantitatively describe the anisotropy of a rock fracture surface. A parameter, referred to as the index for the accumulation power spectral density psd*, is proposed to characterize the anisotropy of a rock fracture surface. Variation of psd*, with orientation angle θ of sampling, is also discussed

Wettability and Impact Performance of Wood Veneer/Polyester Composites

Directory of Open Access Journals (Sweden)

Shayesteh Haghdan

2015-07-01

Full Text Available Fiber-reinforced thermosetting composites have been of interest since the 1940s due to their ease of use in processing, fast curing times, and high specific stiffness and strength. While the use of plant fibers in a polyester matrix has been thoroughly studied, only limited information is available regarding using wood as reinforcement. In this study, composites of thin wood veneer and a polyester matrix were made and the difficulties in the lamination and curing processes were investigated. Sheets of Douglas fir, maple, and oak veneers using a catalyzed polyester resin were assembled as unidirectional, balanced, and unbalanced cross-ply laminates. These were compared to control specimens using glass fiber as reinforcement. The impact properties of the samples, with respect to the laminate thicknesses, were characterized using a drop-weight impact tester. The wettability and surface roughness of unsanded and sanded wood veneers were also investigated. Results showed that Douglas fir cross-ply laminates had an impact energy equivalent to glass fiber laminates, making them an interesting alternative to synthetic fiber composites. Wood/polyester laminates absorbed a considerable amount of energy through a higher number of fracture modes. The balanced lay-up limited twisting of the wood/polyester composites. The lowest contact angle and highest wettability were observed in unsanded Douglas fir veneers.

DEVELOPMENT OF RESERVOIR CHARACTERIZATION TECHNIQUES AND PRODUCTION MODELS FOR EXPLOITING NATURALLY FRACTURED RESERVOIRS

Energy Technology Data Exchange (ETDEWEB)

Michael L. Wiggins; Raymon L. Brown; Faruk Civan; Richard G. Hughes

2002-12-31

For many years, geoscientists and engineers have undertaken research to characterize naturally fractured reservoirs. Geoscientists have focused on understanding the process of fracturing and the subsequent measurement and description of fracture characteristics. Engineers have concentrated on the fluid flow behavior in the fracture-porous media system and the development of models to predict the hydrocarbon production from these complex systems. This research attempts to integrate these two complementary views to develop a quantitative reservoir characterization methodology and flow performance model for naturally fractured reservoirs. The research has focused on estimating naturally fractured reservoir properties from seismic data, predicting fracture characteristics from well logs, and developing a naturally fractured reservoir simulator. It is important to develop techniques that can be applied to estimate the important parameters in predicting the performance of naturally fractured reservoirs. This project proposes a method to relate seismic properties to the elastic compliance and permeability of the reservoir based upon a sugar cube model. In addition, methods are presented to use conventional well logs to estimate localized fracture information for reservoir characterization purposes. The ability to estimate fracture information from conventional well logs is very important in older wells where data are often limited. Finally, a desktop naturally fractured reservoir simulator has been developed for the purpose of predicting the performance of these complex reservoirs. The simulator incorporates vertical and horizontal wellbore models, methods to handle matrix to fracture fluid transfer, and fracture permeability tensors. This research project has developed methods to characterize and study the performance of naturally fractured reservoirs that integrate geoscience and engineering data. This is an important step in developing exploitation strategies for

Synthesis and Characterization of Pure Copper Nanostructures Using Wood Inherent Architecture as a Natural Template

Science.gov (United States)

Dong, Youming; Wang, Kaili; Tan, Yi; Wang, Qingchun; Li, Jianzhang; Mark, Hughes; Zhang, Shifeng

2018-04-01

The inherent sophisticated structure of wood inspires researchers to use it as a natural template for synthesizing functional nanoparticles. In this study, pure copper nanoparticles were synthesized using poplar wood as a natural inexpensive and renewable template. The crystal structure and morphologies of the copper nanoparticles were characterized by X-ray diffraction and field emission scanning electron microscopy. The optical properties, antibacterial properties, and stability of the hybrid wood materials were also tested. Due to the hierarchical and anisotropic structure and electron-rich components of wood, pure copper nanoparticles with high stability were synthesized with fcc structure and uniform sizes and then assembled into corncob-like copper deposits along the wood cell lumina. The products of nanoparticles depended strongly on the initial OH- concentration. With an increase in OH- concentration, Cu2O gradually decreased and Cu remained. Due to the restrictions inherent in wood structure, the derived Cu nanoparticles showed similar grain size in spite of increased Cu2+ concentration. This combination of Cu nanostructures and wood exhibited remarkable optical and antibacterial properties.

Site characterization and validation - drift and borehole fracture data. Stage 1

International Nuclear Information System (INIS)

Gale, J.; Straahle, A.

1988-09-01

This report describes the procedures used in mapping fractures intersecting seven scanlines along the southern and eastern boundaries of the Site Characterization and Validation (SCV) site and the procedures used in logging and orienting the fractures intersecting the core from six 'boundary boreholes' that were drilled as part of the site characterization program for the SCV site at the 360 m level in the Stripa mine. Scanline mapping along the mine drifts provided a detailed description of the fracture geomentry on the boundaries of the SCV site. The cores from the boundary boreholes have been logged, reconstructed and oriented using a borehole Televiewer and a borehole TV camera and the true fracture orientations calcilated. This has provide additional data on the fracture geometry within the SCV site. The fractire data from both the scanlines and the core logging are presented in the appendices. In addition, an initial analysis has been completed of the fracture orientations, trace lengths and spacings. Based on the variation in fracture orientations over the SCV site, there are two strong subvertical fracture sets or or clusters and a poorly represented sub-horizontal fracture set. An empirical approach, based on the 'blind zone' concept has been used to correct for orientation bias and to predict the orientations of the fracture system that will be intersected by the C and D boreholes in stage III. (33 figs., 6 tabl., 19 refs.)

Time-resolved characterization of primary emissions from residential wood combustion appliances.

Science.gov (United States)

Heringa, M F; DeCarlo, P F; Chirico, R; Lauber, A; Doberer, A; Good, J; Nussbaumer, T; Keller, A; Burtscher, H; Richard, A; Miljevic, B; Prevot, A S H; Baltensperger, U

2012-10-16

Primary emissions from a log wood burner and a pellet boiler were characterized by online measurements of the organic aerosol (OA) using a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) and of black carbon (BC). The OA and BC concentrations measured during the burning cycle of the log wood burner, batch wise fueled with wood logs, were highly variable and generally dominated by BC. The emissions of the pellet burner had, besides inorganic material, a high fraction of OA and a minor contribution of BC. However, during artificially induced poor burning BC was the dominating species with ∼80% of the measured mass. The elemental O:C ratio of the OA was generally found in the range of 0.2-0.5 during the startup phase or after reloading of the log wood burner. During the burnout or smoldering phase, O:C ratios increased up to 1.6-1.7, which is similar to the ratios found for the pellet boiler during stable burning conditions and higher than the O:C ratios observed for highly aged ambient OA. The organic emissions of both burners have a very similar H:C ratio at a given O:C ratio and therefore fall on the same line in the Van Krevelen diagram.

High-resolution Fracture Characterization Using Elastic Full-waveform Inversion

KAUST Repository

Zhang, Z.; Tsvankin, I.; Alkhalifah, Tariq Ali

2017-01-01

Current methodologies to characterize fractures at the reservoir scale have serious limitations in spatial resolution. Here, we propose to estimate both the spatial distribution and physical properties of fractures using full waveform inversion (FWI) of multicomponent surface seismic data. An effective orthorhombic medium with five clusters of vertical fractures distributed in a checkboard fashion is used to test the algorithm. To better understand the inversion results, we analyze the FWI radiation patterns of the fracture weaknesses. A shape regularization term is added to the objective function to improve the inversion for the horizontal weakness, which is otherwise poorly constrained. Alternatively, a simplified model of penny-shaped cracks is used to reduce the nonuniqueness in the inverted weaknesses and achieve a faster convergence.

High-resolution Fracture Characterization Using Elastic Full-waveform Inversion

KAUST Repository

Zhang, Z.

2017-05-26

Current methodologies to characterize fractures at the reservoir scale have serious limitations in spatial resolution. Here, we propose to estimate both the spatial distribution and physical properties of fractures using full waveform inversion (FWI) of multicomponent surface seismic data. An effective orthorhombic medium with five clusters of vertical fractures distributed in a checkboard fashion is used to test the algorithm. To better understand the inversion results, we analyze the FWI radiation patterns of the fracture weaknesses. A shape regularization term is added to the objective function to improve the inversion for the horizontal weakness, which is otherwise poorly constrained. Alternatively, a simplified model of penny-shaped cracks is used to reduce the nonuniqueness in the inverted weaknesses and achieve a faster convergence.

Influence of Maleic Anhydride/Glycidyl Methacrylate Cografted Polylactic Acid on Properties of Wood Flour/PLA Composites

Directory of Open Access Journals (Sweden)

DU Jun

2017-12-01

Full Text Available Graft copolymers of PLA-g-MAH, PLA-g-GMA and PLA-co-MAH/GMA were prepared by means of melt grafting. The structure of the graft copolymers were characterized by FTIR.Wood flour/PLA composites were prepared by injection molding with three kinds of graft copolymers as compatibilizers, and the fractured morphology of composites was investigated by scanning electron microscope (SEM. Results show that there is no obvious phase interface between wood flour and PLA,which indicating the interfacial compatibility of wood flour/PLA composites is improved after adding different graft copolymers. The determination results of mechanical properties, processing flowability and dynamic rheological property of composites prepared with different graft copolymers reveal that, compared to the composite without compatibilizer, the tensile strength and impact strength of wood flour/PLA composites are increased by 9.54% and 7.23% respectively, and the equilibrium torque, shear heat, storage modulus and complex viscosity are all increased after adding maleic anhydride/glycidyl methacrylate cografted polylactic acid.

Synthesis and characterization of copper-infiltrated carbonized wood monoliths for supercapacitor electrodes

International Nuclear Information System (INIS)

Teng, Shiang; Siegel, Gene; Prestgard, Megan C.; Wang, Wei; Tiwari, Ashutosh

2015-01-01

Highlights: • Copper nanoparticles were embedded in the highly porous carbonized wood electrodes. • Copper nanoparticle serves as the pseudocapacitive specie to increase the energy density. • The porous copper-wood electrodes exhibit excellent electrochemical performances with high capacitance, excellent rate capability and stability. - Abstract: Copper nanoparticle-loaded carbonized wood electrodes were synthesized and characterized for the use as supercapacitor electrodes. The electrodes were fabricated by soaking beech wood samples in Cu(NO 3 ) 2 solution followed by carbonization at 800 °C under a N 2 atmosphere. The copper nanoparticle content in the electrodes was controlled by varying the concentration of the Cu(NO 3 ) 2 solution from 0.5 to 2 M. Subsequent X-ray diffraction and scanning electron microscopy measurements confirm that cubic copper was formed and the copper nanoparticles were anchored uniformly both on the surface as well as deep within the pores of the wood electrode. Cyclic voltammetry measurements showed that all of the electrodes had a typical pseudo-capacitive behavior, as indicated by the presence of redox reaction peaks. Charge–discharge testing also confirmed the pseudo-capacitive nature of the electrodes. The reversible oxidation of Cu into Cu 2 O and CuO was verified by performing X-ray photoelectron spectroscopy at different stages of the charge–discharge cycle. The Cu-loaded wood electrodes exhibited excellent cyclability and retaining 95% of their specific capacitance even after 2000 cycles. A maximum specific capacitance of 888 F/g was observed while discharging the 7 wt% Cu electrode at 200 mA/g in a 2 M KOH electrolyte solution. These results demonstrated the potential of the copper nanoparticle-loaded wood electrodes as cheap and high performance supercapacitor electrodes

VSP [Vertical Seismic Profiling] and cross hole tomographic imaging for fracture characterization

International Nuclear Information System (INIS)

Majer, E.L.; Peterson, J.E.; Myer, L.R.; Karasaki, K.; Daley, T.M.; Long, J.C.S.

1989-09-01

For the past several years LBL has been carrying out experiments at various fractured rock sites to determine the fundamental nature of the propagation of seismic waves in fractured media. These experiments have been utilizing high frequency (1000 to 10000 Hz.) signals in a cross-hole configuration at scales of several tens of meters. Three component sources and receivers are used to map fracture density, and orientation. The goal of the experiments has been to relate the seismological parameters to the hydrological parameters, if possible, in order to provide a more accurate description of a starting model for hydrological characterization. The work is ultimately aimed at the characterization and monitoring of the Yucca Mountain site for the storage of nuclear waste. In addition to these controlled experiments multicomponent VSP work has been carried out at several sites to determine fracture characteristics. The results to date indicate that both P-wave and S-wave can be used to map the location of fractures. In addition, fractures that are open and conductive are much more visible to seismic waves that non-conductive fractures. The results of these tests indicate direct use in an unsaturated environment. 12 refs., 10 figs

Surface characterization of weathered wood-plastic composites produced from modified wood flour

Science.gov (United States)

James S. Fabiyi; Armando G. McDonald; Nicole M. Stark

2007-01-01

The effects of weathering on the surface properties of wood-plastic composites (WPC) were examined. High-density polyethylene (HDPE) based WPCs made from modified wood flour (untreated, extractives free, and holocellulose (delignified) fibers) were subjected to accelerated (xenon-arc) weathering. Colorimetry and Fourier-transform infrared spectroscopy were employed to...

Multi-Attribute Seismic/Rock Physics Approach to Characterizing Fractured Reservoirs

Energy Technology Data Exchange (ETDEWEB)

Gary Mavko

2004-11-30

Most current seismic methods to seismically characterize fractures in tight reservoirs depend on a few anisotropic wave propagation signatures that can arise from aligned fractures. While seismic anisotropy can be a powerful fracture diagnostic, a number of situations can lessen its usefulness or introduce interpretation ambiguities. Fortunately, laboratory and theoretical work in rock physics indicates that a much broader spectrum of fracture seismic signatures can occur, including a decrease in P- and S-wave velocities, a change in Poisson's ratio, an increase in velocity dispersion and wave attenuation, as well as well as indirect images of structural features that can control fracture occurrence. The goal of this project was to demonstrate a practical interpretation and integration strategy for detecting and characterizing natural fractures in rocks. The approach was to exploit as many sources of information as possible, and to use the principles of rock physics as the link among seismic, geologic, and log data. Since no single seismic attribute is a reliable fracture indicator in all situations, the focus was to develop a quantitative scheme for integrating the diverse sources of information. The integrated study incorporated three key elements: The first element was establishing prior constraints on fracture occurrence, based on laboratory data, previous field observations, and geologic patterns of fracturing. The geologic aspects include analysis of the stratigraphic, structural, and tectonic environments of the field sites. Field observations and geomechanical analysis indicates that fractures tend to occur in the more brittle facies, for example, in tight sands and carbonates. In contrast, strain in shale is more likely to be accommodated by ductile flow. Hence, prior knowledge of bed thickness and facies architecture, calibrated to outcrops, are powerful constraints on the interpreted fracture distribution. Another important constraint is that

Defect characterization, diagnosis and repair of wood flooring based on a field survey

International Nuclear Information System (INIS)

Delgado, A.; Pereira, C.; Brito, J. de; Silvestre, J.D.

2018-01-01

A statistical characterization of defects in 35 buildings and 98 wood floorings (softwood and hardwood floors, and laminated and engineered wood floors), their diagnostic methods and repair solutions is presented. An expert system for inspecting wood flooring, comprising the classification of defects, their most probable causes, diagnostic methods and repair techniques, was used. Results include age, affected area, severity and frequency of defects and their main causes, as well as appropriate diagnostic methods, preventive and curative repair solutions most prescribed and the most significant correlations. Scratches were detected in more than five sixths of the sample, highly associated with exterior mechanical actions, and with an inadequate finishing layer. Wearing of the finishing layer was detected in a quarter of the inspected floorings. Accordingly, the application of a suitable finishing layer and, alternatively, its replacement are the most prescribed repair techniques. [es

Precision wood particle feedstocks

Science.gov (United States)

Dooley, James H; Lanning, David N

2013-07-30

Wood particles having fibers aligned in a grain, wherein: the wood particles are characterized by a length dimension (L) aligned substantially parallel to the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L; the L.times.H dimensions define two side surfaces characterized by substantially intact longitudinally arrayed fibers; the W.times.H dimensions define two cross-grain end surfaces characterized individually as aligned either normal to the grain or oblique to the grain; the L.times.W dimensions define two substantially parallel top and bottom surfaces; and, a majority of the W.times.H surfaces in the mixture of wood particles have end checking.

Synthesis and characterization of polypropylene/jigsaw wood ash composite

International Nuclear Information System (INIS)

Sudirman; Karo Karo, Aloma; Gunawan, Indra; Handayani, Ari; Hertinvyana, Evi

2002-01-01

The composite of polypropylene (PP) polymer with jigsaw wood ash as filler is the alternative composite material. The dispersion of the filler in the composite is random with the jigsaw wood ash composition of 10,30, and 50% by volume. The characterization of composite are done to measure its mechanical properties, physical properties and microstructure by using XRD and SEM. From this research, it is concluded that increasing filler content of the composite will decrease its mechanical and physical properties. The comparation of different composites are found that tensile strength of PP MF 10 is higher 4.24% compared with PP MF 2 as a matrix. It is also found that melting temperature of PP MF 10 is higher 4.09% compared with PP MF 2 as a matrices and the decomposition temperature different is 0.17%. The degree of crystallinity of composite with PP MF 10 as a matrices is 2.55% higher compared with PP MF 2. The higher degree of crystallinity is increasing the tensile strength

Mode II Interlaminar Fracture Toughness and Fatigue Characterization of a Graphite Epoxy Composite Material

Science.gov (United States)

O'Brien, T. Kevin; Johnston, William M.; Toland, Gregory J.

2010-01-01

Mode II interlaminar fracture toughness and delamination onset and growth characterization data were generated for IM7/8552 graphite epoxy composite materials from two suppliers for use in fracture mechanics analyses. Both the fracture toughness testing and the fatigue testing were conducted using the End-notched Flexure (ENF) test. The ENF test for mode II fracture toughness is currently under review by ASTM as a potential standard test method. This current draft ASTM protocol was used as a guide to conduct the tests on the IM7/8552 material. This report summarizes the test approach, methods, procedures and results of this characterization effort.

A multidisciplinary fractured rock characterization study at Raymond field site, Raymond, California

International Nuclear Information System (INIS)

Karasaki, Kenzi; Freifeld, Barry; Cohen, Andrew; Cook, Paul; Vasco, Don; Grossenbacher, Ken

2001-01-01

A dedicated field site was developed and a suite of experiments were conducted in the Sierra Nevada foothills, near the town of Raymond, California to develop and test a multi-disciplinary approach to the characterization of groundwater flow and transport in fractured rocks. A wealth of geologic, hydrologic and geophysical data was collected at the site using a variety of unique tools. A cluster of nine approximately 90 m deep boreholes were drilled at the site in a V-shaped pattern with an angle of 60 degrees. The boreholes are spaced 7.5, 15, 30, and 60 meters from the central borehole. Various geophysical and hydrologic tests were conducted in and between these boreholes. Integration of cross-hole radar and seismic tomography, borehole flow surveys and images from a new digital borehole scanner indicated that groundwater flow is mainly confined to a few sub-horizontal fracture zones. A unique suite of hydraulic tests were conducted, in which three to four intervals in each of the nine boreholes were isolated using pneumatic packers. Some 130 injection tests were conducted, and more than 4,100 cross-hole transient pressure measurements were obtained. A computer algorithm was developed to analyze such massive interference data systematically. As a result of the analysis, an image of the fracture connections emerged, which is consistent with the geophysical data. High precision tiltmeters were effective in remotely characterizing the preferential flow path. Several radial convergent tracer tests were conducted by injecting a mixture of several conservative tracers and one sorbing tracer: deuterium, fluorescein, lithium bromide and polystyrene micro-spheres. Some differences between the breakthrough curves are observed, which may be due to possible differences among so-called 'conservative' tracers. Some characterization tools were found to be more effective than others in locating flowing fractures. However, no single tool was almighty. Characterization of

Fracture mechanics

CERN Document Server

Perez, Nestor

2017-01-01

The second edition of this textbook includes a refined presentation of concepts in each chapter, additional examples; new problems and sections, such as conformal mapping and mechanical behavior of wood; while retaining all the features of the original book. The material included in this book is based upon the development of analytical and numerical procedures pertinent to particular fields of linear elastic fracture mechanics (LEFM) and plastic fracture mechanics (PFM), including mixed-mode-loading interaction. The mathematical approach undertaken herein is coupled with a brief review of several fracture theories available in cited references, along with many color images and figures. Dynamic fracture mechanics is included through the field of fatigue and Charpy impact testing. Explains computational and engineering approaches for solving crack-related problems using straightforward mathematics that facilitate comprehension of the physical meaning of crack growth processes; Expands computational understandin...

Physical-mechanical and anatomical characterization in 26-year-old Eucalyptus resinifera wood

Directory of Open Access Journals (Sweden)

Israel Luiz de Lima

Full Text Available In the present study, we aimed to characterize Eucalyptus resinifera wood through physical and mechanical assays and wood anatomy studies, as well as determine the relationships between the properties and anatomy of wood. We used samples collected from the area close to the bark of ten 26-year-old E. resinifera trees. We concluded that the specific gravity (Gb, compression (f c0, and shear parallel to grain (f v0 were ranked in strength classes C30, C40 and C60, respectively, and that volumetric shrinkage (VS was ranked as high. A positive relationship between Gb and f v0 results from the higher specific gravity associated with higher tissue proportion, in turn, causing higher shear strength. Higher ray frequency increases shear strength, because rays act as reinforcing elements. A negative relationship between VS and vessel diameter occurs because vessel walls are highly resistant to collapse, and since larger lumens represent a higher proportion of empty spaces, less tissue is available for shrinkage.

Topological Characterization of Fractured Coal

Science.gov (United States)

Jing, Yu; Armstrong, Ryan T.; Ramandi, Hamed L.; Mostaghimi, Peyman

2017-12-01

Coal transport properties are highly dependent on the underlying fractured network, known as cleats, which are characterized by geometrical and topological properties. X-ray microcomputed tomography (micro-CT) has been widely applied to obtain 3-D digital representations of the cleat network. However, segmentation of 3-D data is often problematic due to image noise, which will result in inaccurate estimation of coal properties (e.g., porosity and specific surface area). To circumvent this issue, a discrete fracture network (DFN) model is proposed. We develop a characterization framework to determine if the developed DFN models can preserve the topological properties of the coal cleat network found in micro-CT data. We compute the Euler characteristic, fractal dimension, and percolation quantities to analyze the topology locally and globally and compare the results between micro-CT data (before denoising), filtered micro-CT data (after denoising), and the DFN model. We find that micro-CT data with noise have extensive connectivity while filtered micro-CT data and DFN models have similar topology both globally and locally. It is concluded that the topology of the DFN models are closer to that of the realistic cleat network that do not have segmentation-induced pores. In addition, micro-CT imaging always struggles with the trade-off between sample size and resolution, while the presented DFN models are not restricted by imaging resolution and thus can be constructed with extended domain size. Overall, the presented DFN model is a reliable alternative with realistic cleat topology, extended domain size and favorable data format for direct numerical simulations.

Integrated workflow for characterizing and modeling fracture network in unconventional reservoirs using microseismic data

Science.gov (United States)

Ayatollahy Tafti, Tayeb

We develop a new method for integrating information and data from different sources. We also construct a comprehensive workflow for characterizing and modeling a fracture network in unconventional reservoirs, using microseismic data. The methodology is based on combination of several mathematical and artificial intelligent techniques, including geostatistics, fractal analysis, fuzzy logic, and neural networks. The study contributes to scholarly knowledge base on the characterization and modeling fractured reservoirs in several ways; including a versatile workflow with a novel objective functions. Some the characteristics of the methods are listed below: 1. The new method is an effective fracture characterization procedure estimates different fracture properties. Unlike the existing methods, the new approach is not dependent on the location of events. It is able to integrate all multi-scaled and diverse fracture information from different methodologies. 2. It offers an improved procedure to create compressional and shear velocity models as a preamble for delineating anomalies and map structures of interest and to correlate velocity anomalies with fracture swarms and other reservoir properties of interest. 3. It offers an effective way to obtain the fractal dimension of microseismic events and identify the pattern complexity, connectivity, and mechanism of the created fracture network. 4. It offers an innovative method for monitoring the fracture movement in different stages of stimulation that can be used to optimize the process. 5. Our newly developed MDFN approach allows to create a discrete fracture network model using only microseismic data with potential cost reduction. It also imposes fractal dimension as a constraint on other fracture modeling approaches, which increases the visual similarity between the modeled networks and the real network over the simulated volume.

Characterizing, modelling and optimizing the sound absorption of wood wool cement boards (WWCB)

NARCIS (Netherlands)

Botterman, B.; Hornikx, M.C.J.; Doudart de la Grée, G.C.H.; Yu, Q.; Brouwers, H.J.H.

2016-01-01

The present article aims to characterize and, by using impedance models, predict the sound absorption of wood wool cement boards (WWCB). The main challenge lies in the inhomogeneity of the WWCB; the samples taken from different commercial boards do not only greatly differ in density, but also in

Dynamic fracture characterization of material

International Nuclear Information System (INIS)

Kobayashi, A.S.; Emery, A.F.; Liaw, B.M.

1981-01-01

The influences of a wide range of material properties, i.e. of A533B steel, a silicon nitride ceramic and a Homalite-100 photoelastic polymer, as well as the influences of the specimen sizes on the dynamic fracture response of fracture specimens are presented in this paper. The results of a numerical study show that the dynamic fracture responses of these fracture specimens of proportional dimensions were indistinguishable provided the normalized dynamic fracture toughness versus normalized crack velocity relations of the three materials coincide. The limited results suggest that should the normalized dynamic fracture toughness versus normalized crack velocity relations between prototype and model materials coincide, then dynamic fracture experiments on scaled models can be used to infer the dynamic fracture response of the prototype. (orig./HP)

Prediction of strength of wood composite materials using ultrasonic

International Nuclear Information System (INIS)

Mahmoud, M.K.; Emam, A.

2005-01-01

Wood is a biological material integrating a very large variability of its mechanical properties (tensile and compressive), on the two directional longitudinal and transverse Ultrasonic method has been utilized to measure both wood physical and / or wood mechanical properties. The aim of this article is to show the development of ultrasonic technique for quality evaluation of trees, wood material and wood based composites. For quality assessment of these products we discuss the nondestructive evaluation of different factors such as: moisture content, temperature, biological degradation induced by bacterial attack and fungal attack. These techniques were adapted for trees, timber and wood based composites. The present study discusses the prediction of tensile and compressive strength of wood composite materials using ultrasonic testing. Empirical relationships between the tensile properties, compression strength and ultrasonic were proposed. The experimental results indicate the possibility of establishing a relationship between tensile strength and compression values. Moreover, the fractures in tensile and compressive are discussed by photographic

Seismic Fracture Characterization Methodologies for Enhanced Geothermal Systems

Energy Technology Data Exchange (ETDEWEB)

Queen, John H. [Hi-Geophysical, Inc., Ponca, OK (United States)

2016-05-09

Executive Summary The overall objective of this work was the development of surface and borehole seismic methodologies using both compressional and shear waves for characterizing faults and fractures in Enhanced Geothermal Systems. We used both surface seismic and vertical seismic profile (VSP) methods. We adapted these methods to the unique conditions encountered in Enhanced Geothermal Systems (EGS) creation. These conditions include geological environments with volcanic cover, highly altered rocks, severe structure, extreme near surface velocity contrasts and lack of distinct velocity contrasts at depth. One of the objectives was the development of methods for identifying more appropriate seismic acquisition parameters for overcoming problems associated with these geological factors. Because temperatures up to 300º C are often encountered in these systems, another objective was the testing of VSP borehole tools capable of operating at depths in excess of 1,000 m and at temperatures in excess of 200º C. A final objective was the development of new processing and interpretation techniques based on scattering and time-frequency analysis, as well as the application of modern seismic migration imaging algorithms to seismic data acquired over geothermal areas. The use of surface seismic reflection data at Brady's Hot Springs was found useful in building a geological model, but only when combined with other extensive geological and geophysical data. The use of fine source and geophone spacing was critical in producing useful images. The surface seismic reflection data gave no information about the internal structure (extent, thickness and filling) of faults and fractures, and modeling suggests that they are unlikely to do so. Time-frequency analysis was applied to these data, but was not found to be significantly useful in their interpretation. Modeling does indicate that VSP and other seismic methods with sensors located at depth in wells will be the most

Acoustic emission characterization of fracture toughness for fiber reinforced ceramic matrix composites

International Nuclear Information System (INIS)

Mei, Hui; Sun, Yuyao; Zhang, Lidong; Wang, Hongqin; Cheng, Laifei

2013-01-01

The fracture toughness of a carbon fiber reinforced silicon carbide composite was investigated relating to classical critical stress intensity factor K IC , work of fracture, and acoustic emission energy. The K IC was obtained by the single edge notch beam method and the work of fracture was calculated using the featured area under the load–displacement curves. The K IC , work of fracture, and acoustic emission energy were compared for the composites before and after heat treatment and then analyzed associated with toughening microstructures of fiber pullout. It indicates that the work of fracture and acoustic emission energy can be more suitable to reflect the toughness rather than the traditional K IC , which has certain limitation for the fracture toughness characterization of the crack tolerant fiber ceramic composites.

Isolation and characterization of mold fungi and insects infecting sawmill wood, and their inhibition by gamma radiation

Science.gov (United States)

Kalawate, Aparna; Mehetre, Sayaji

2015-12-01

This article describes the isolation, identification, and characterization of wood-rotting fungi and insects, and their inhibition was studied using gamma radiation. Products manufactured from plantation timber species are deteriorated by wood-rotting fungi such as Hypocrea lixii, Fusarium proliferatum, and Aspergillus flavus, and insects such as powderpost beetles. Proper preservation methods are necessary for ensuring a long service life of wood products. In this study, wood samples were treated with 2.5% copper ethanolamine boron (CEB) (10% w/v) and subsequently irradiated with gamma rays (10 kGy). It was observed that CEB-treated and gamma-irradiated samples controlled fungi and powderpost beetles significantly. As wood is a dead organic material, penetration of chemicals into it is very difficult. Gamma rays easily pass through wooden objects with hidden eggs and dormant spores of insects and fungi, respectively. Gamma irradiation was proved very effective in reducing damage caused by both fungi and insects.

Photostability Characterization of Wood Polymer Composites of Polyvinyl Chloride and Rice Husk to Ultra-Violet Irradiation Exposure

Directory of Open Access Journals (Sweden)

Jais Farhana Hazwanee M.

2016-01-01

Full Text Available In this study, the photostability of wood polymer composites (WPC was assessed by using ultra-violet accelerated weathering test. Meanwhile, the mechanical properties of WPC show strength improvement at prolonged UV irradiation exposure with 43.21 MPa and maximum strain of 4.08 % at 5000 hours and 1000 hours UV irradiation exposure respectively. The colour stability of WPC was improved by addition of Ultraviolet (UV stabilizer during pre-mixing process which shows positive effect on the colour stability and prevented chalking of the composites for external use. Generally, discolourations of WPC during test exposure were caused by degradation of both wood and plastic. Therefore, incorporation with pigments and other additives gives improvement to the photostability of WPC. This is based on the increment of WPCs mechanical property while the morphological fracture surface of dumbbell test specimens revealed the pull out rice husk fiber which contributed to the distribution of load in the WPC samples.

Seismic characterization of fracture properties

International Nuclear Information System (INIS)

Myer, L.R.; Hopkins, D.; Cook, N.G.W.; Pyrak-Nolte, L.J.

1990-01-01

The purpose of this paper is to show that there is a relationship, both empirical and theoretical, between the measured seismic response, the mechanical stiffness (also referred to as specific stiffness) of fractures and their hydraulic conductivity. Laboratory measurements of the mechanical stiffness, hydraulic conductivity and seismic properties of natural fractures are summarized. A theoretical model for the amplitude and group time delay for compressional and shear waves transmitted across a single fracture is presented. Predictions based on this model are compared with laboratory measurements. Finally, the results for a single fracture are extended to multiple parallel fractures. 13 refs., 6 figs

Characterization and potential recycling of home building wood waste

Science.gov (United States)

Philip A. Araman; D.P. Hindman; M.F. Winn

2010-01-01

Construction waste represents a significant portion of landfill waste, estimated as 17% of the total waste stream. Wood construction waste of a 2000 square foot single family home we found to be 1500-3700 lbs of solid-sawn wood, and 1000-1800 lbs of engineered wood products (EWP). Much of the solid-sawn lumber and EWPs could be recycled into several products. Through a...

Application of artificial intelligence to characterize naturally fractured zones in Hassi Messaoud Oil Field, Algeria

Energy Technology Data Exchange (ETDEWEB)

El Ouahed, Abdelkader Kouider; Mazouzi, Amine [Sonatrach, Rue Djenane Malik, Hydra, Algiers (Algeria); Tiab, Djebbar [Mewbourne School of Petroleum and Geological Engineering, The University of Oklahoma, 100 East Boyd Street, SEC T310, Norman, OK, 73019 (United States)

2005-12-15

In highly heterogeneous reservoirs classical characterization methods often fail to detect the location and orientation of the fractures. Recent applications of Artificial Intelligence to the area of reservoir characterization have made this challenge a possible practice. Such a practice consists of seeking the complex relationship between the fracture index and some geological and geomechanical drivers (facies, porosity, permeability, bed thickness, proximity to faults, slopes and curvatures of the structure) in order to obtain a fracture intensity map using Fuzzy Logic and Neural Network. This paper shows the successful application of Artificial Intelligence tools such as Artificial Neural Network and Fuzzy Logic to characterize naturally fractured reservoirs. A 2D fracture intensity map and fracture network map in a large block of Hassi Messaoud field have been developed using Artificial Neural Network and Fuzzy Logic. This was achieved by first building the geological model of the permeability, porosity and shale volume using stochastic conditional simulation. Then by applying some geomechanical concepts first and second structure directional derivatives, distance to the nearest fault, and bed thickness were calculated throughout the entire area of interest. Two methods were then used to select the appropriate fracture intensity index. In the first method well performance was used as a fracture index. In the second method a Fuzzy Inference System (FIS) was built. Using this FIS, static and dynamic data were coupled to reduce the uncertainty, which resulted in a more reliable Fracture Index. The different geological and geomechanical drivers were ranked with the corresponding fracture index for both methods using a Fuzzy Ranking algorithm. Only important and measurable data were selected to be mapped with the appropriate fracture index using a feed forward Back Propagation Neural Network (BPNN). The neural network was then used to obtain a fracture intensity

Fracture Characterization of Sandwich Face/Core Interfaces

DEFF Research Database (Denmark)

Manca, Marcello

of load transfer between the faces and the core layer is lost, the debonds are considered as primary damage initiators. Under fatigue loading the debonds may evolve into cracks that cause a reduction in structural performance and consequent failure. At present most structural design is based on “life-time...... of sandwich structures is defects that are introduced in the manufacturing process. It is inevitable that areas of the face sheets will not fully adhere to the core resulting in defects known as “debonds”. Debonds can also be induced in-service due to e.g. localised impact loading or overloading. As the means...... such result it is important to devise new experimental and analytical techniques to establish the multi-mode fracture characteristics of sandwich plate structures and accordingly develop methods to inhibit defect propagation. This thesis deals with characterization of fracture between face and core...

An overview of geophysical technologies appropriate for characterization and monitoring at fractured-rock sites

Science.gov (United States)

Geophysical methods are used increasingly for characterization and monitoring at remediation sites in fractured-rock aquifers. The complex heterogeneity of fractured rock poses enormous challenges to groundwater remediation professionals, and new methods are needed to cost-effect...

Wood quality changes caused by mineral fertilization

Directory of Open Access Journals (Sweden)

Carlos Roberto Sette Jr

2014-06-01

Full Text Available The diverse and important use of wood from fast growth eucalyptus plantations requires the analysis of the effect of mineral fertilizers on wood quality. The objective of this study was to evaluate the anatomical characteristics and wood density from Eucalyptus grandis trees (3 m x 2 m spacing fertilized with potassium and sodium (at planting, 6 th and 12th month. Fifteen (15 6 years old eucalyptus trees were selected (5 trees/treatment, cut and wood samples at DBH (1,3 m were taken for anatomical characteristics (fiber and vessels and wood density analysis. Results showed that eucalyptus trees treated with mineral fertilizers did not show significant alteration in average wood density, with radial profile model common to all three treatments, characterized by a values increase in the region next to the pith, toward to bark. Mineral fertilization influenced wood anatomical characteristics: treatment with sodium was characterized by thinner walls and lumen larger diameter; in treatment with potassium, larger vessels were detected.

Hot and Steamy Fractures in the Philippines: The Geological Characterization and Permeability Evaluation of Fractures in the Southern Negros Geothermal Field, Philippines

Science.gov (United States)

Pastoriza, L. R.; Holdsworth, R.; McCaffrey, K. J. W.; Dempsey, E. D.; Walker, R. J.; Gluyas, J.; Reyes, J. K.

2016-12-01

Fluid flow pathway characterization is critical to geothermal exploration and exploitation. It requires a good understanding of the structural evolution, fault distribution and fluid flow properties. A dominantly fieldwork-based approach has been used to evaluate the potential fracture permeability characteristics of a typical high-temperature geothermal reservoir in the Southern Negros Geothermal Field, Philippines. This is a liquid-dominated geothermal resource hosted in the andesitic to dacitic Quaternary Cuernos de Negros Volcano in Negros Island. Fieldwork reveals two main fracture groups based on fault rock characteristics, alteration type, relative age of deformation, and associated thermal manifestation, with the younger fractures mainly related to the development of the modern geothermal system. Palaeostress analyses of cross-cutting fault and fracture arrays reveal a progressive counterclockwise rotation of stress axes from the (?)Pliocene up to the present-day, which is consistent with the regional tectonic models. A combined slip and dilation tendency analysis of the mapped faults indicates that NW-SE structures should be particularly promising drilling targets. Frequency versus length and aperture plots of fractures across six to eight orders of magnitude show power-law relationships with a change in scaling exponent in the region of 100 to 500m length-scales. Finally, evaluation of the topology of the fracture branches shows the dominance of Y-nodes that are mostly doubly connected suggesting good connectivity and permeability within the fracture networks. The results obtained in this study illustrate the value of methods that can be globally applied during exploration to better characterize fracture systems in geothermal reservoirs using multiscale datasets.

Synthesis and characterization of poly aniline/wood and poly aniline/carbon composites

International Nuclear Information System (INIS)

Kanwal, F.; Siddiqi, S.A.; Tasleem, S.

2009-01-01

Conducting polymers have shown many applications in the field of nano science, nano technology and nuclear science. Poly aniline (PAN I) is the most studied conducting polymer due to its environmental stability, easy availability of its raw materials, and simple synthesis. We have synthesized poly aniline and two of its conducting composites i.e., poly aniline-carbon and poly aniline-wood in acidic medium (HCI) using K/sub 2/Cr/sub 2/O/sub 7/ as oxidizing agent. All samples were characterized by FTIR and four-probe d.c. conductivity methods The synthesis was carried out at two different temperatures (0 degree C and -5 degree C) and it was found that the yield and conductivity were maximum at lower temperature (-5 degree C). The poly aniline-carbon composites showed enhanced conductivity whereas poly aniline-wood composites showed reduced conductivity when compared with the conductivity of pure poly aniline. (author)

Characterizing fractured rock for fluid-flow, geomechanical, and paleostress modeling: Methods and preliminary results from Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Barton, C.C.; Larsen, E.; Page, W.R.; Howard, T.M.

1993-01-01

Fractures have been characterized for fluid-flow, geomechanical, and paleostress modeling at three localities in the vicinity of drill hole USW G-4 at Yucca Mountain in southwestern Nevada. A method for fracture characterization is introduced that integrates mapping fracture-trace networks and quantifying eight fracture parameters: trace length, orientation, connectivity, aperture, roughness, shear offset, trace-length density, and mineralization. A complex network of fractures was exposed on three 214- to 260-m 2 pavements cleared of debris in the upper lithophysal unit of the Tiva Canyon Member of the Miocene Paint-brush Tuff. The pavements are two-dimensional sections through the three-dimensional network of strata-bound fractures. All fractures with trace lengths greater than 0.2 m were mapped and studied

Styrene-Assisted Maleic Anhydride Grafted Poly(lactic acid as an Effective Compatibilizer for Wood Flour/Poly(lactic acid Bio-Composites

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Jun Du

2017-11-01

Full Text Available This study aimed to evaluate the effect of styrene-assisted maleic anhydride-grafted poly(lactic acid (PLA-g-St/MAH on the interfacial properties of wood flour/poly(lactic acid (PLA bio-composites. PLA-g-St/MAH was synthesized by free-radical melt grafting using styrene as a comonomer and dicumyl peroxide as an initiator. The structure of PLA-g-St/MAH was characterized by Fourier transform infrared spectroscopy. Wood flour/PLA composites were prepared by compression molding using PLA-g-St/MAH as a compatibilizer. The effects of PLA-g-St/MAH on the rheological and mechanical properties, as well as on the fractured surface morphology of the composites were investigated. Results indicated that storage modulus, complex viscosity, equilibrium torque, and shear heat were significantly increased. The mechanical properties of the wood flour/PLA composites were also significantly increased after the addition of PLA-g-St/MAH. The maximum values were achieved at the loading rate of 3 wt % because of the improved interfacial adhesion between the wood flour and the PLA matrix.

Property improvement by gamma polymerization of methyl methacrylate impregnated local Thai wood Yang (Dipterocarpus Sp.)

International Nuclear Information System (INIS)

Saisomboon, S.; Sumitra, T.

1990-01-01

Property improvement of a local Thai wood (Yang-Dipterocarpus Sp.) was studied by impregnating with methyl methacrylate before polymerizing with gamma ray. The polymer loading were 126 and 68 percent for sapwood and heart wood, respectively. Significant improvements in impact, compressive and bending strength were observed in the wood polymer composite (WPC). In addition, the microstructure and the impact fractured-surfaces of WPC were also carried with a scanning electron-microscope

Seismic Characterizations of Fractures: Dynamic Diagnostics

Science.gov (United States)

Pyrak-Nolte, L. J.

2017-12-01

Fracture geometry controls fluid flow in a fracture, affects mechanical stability and influences energy partitioning that affects wave scattering. Our ability to detect and monitor fracture evolution is controlled by the frequency of the signal used to probe a fracture system, i.e. frequency selects the scales. No matter the frequency chosen, some set of discontinuities will be optimal for detection because different wavelengths sample different subsets of fractures. The select subset of fractures is based on the stiffness of the fractures which in turn is linked to fluid flow. A goal is obtaining information from scales outside the optimal detection regime. Fracture geometry trajectories are a potential approach to drive a fracture system across observation scales, i.e. moving systems between effective medium and scattering regimes. Dynamic trajectories (such as perturbing stress, fluid pressure, chemical alteration, etc.) can be used to perturb fracture geometry to enhance scattering or give rise to discrete modes that are intimately related to the micro-structural evolution of a fracture. However, identification of these signal features will require methods for identifying these micro-structural signatures in complicated scattered fields. Acknowledgment: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Geosciences Research Program under Award Number (DE-FG02-09ER16022).

Characterization of wood-based molding bonded with citric acid

OpenAIRE

Umemura, Kenji; Ueda, Tomohide; Kawai, Shuichi

2012-01-01

The wood-based moldings were fabricated by using only citric acid as an adhesive. The mechanical properties, water resistances, thermal properties and chemical structure were investigated. Wood powder obtained from Acacia mangium was mixed with citric acid under certain weight ratios (0-40 wt%), and each powder mixture was molded using two types of metal molds at 200 °C and 4MPa for 10 min. The modulus of rupture (MOR) and the modulus of elasticity (MOE) values of the wood-based molding conta...

Characterizing phenolformaldehyde adhesive cure chemistry within the wood cell wall

Science.gov (United States)

Daniel J. Yelle; John Ralph

2016-01-01

Adhesive bonding of wood using phenol-formaldehyde remains the industrial standard in wood product bond durability. Not only does this adhesive infiltrate the cell wall, it also is believed to form primary bonds with wood cell wall polymers, particularly guaiacyl lignin. However, the mechanism by which phenol-formaldehyde adhesive intergrally interacts and bonds to...

An integrated methodology for sub-surface fracture characterization using microseismic data: A case study at the NW Geysers

Science.gov (United States)

Aminzadeh, Fred; Tafti, Tayeb A.; Maity, Debotyam

2013-04-01

Geothermal and unconventional hydrocarbon reservoirs are often characterized by low permeability and porosity. So, they are difficult to produce and require stimulation techniques, such as thermal shear deactivation and hydraulic fracturing. Fractures provide porosity for fluid storage and permeability for fluid movement and play an important role in production from this kind of reservoirs. Hence, characterization of fractures has become a vitally important consideration in every aspect of exploration, development and production so as to provide additional energy resources for the world. During the injection or production of fluid, induced seismicity (micro-seismic events) can be caused by reactivated shears created fractures or the natural fractures in shear zones and faults. Monitoring these events can help visualize fracture growth during injection stimulation. Although the locations of microseismic events can be a useful characterization tool and have been used by many authors, we go beyond these locations to characterize fractures more reliably. Tomographic inversion, fuzzy clustering, and shear wave splitting are three methods that can be applied to microseismic data to obtain reliable characteristics about fractured areas. In this article, we show how each method can help us in the characterization process. In addition, we demonstrate how they can be integrated with each other or with other data for a more holistic approach. The knowledge gained might be used to optimize drilling targets or stimulation jobs to reduce costs and maximize production. Some of the concepts discussed in this paper are general in nature, and may be more applicable to unconventional hydrocarbon reservoirs than the metamorphic and igneous reservoir rocks at The Geysers geothermal field.

Wood Specific Gravity Variations and Biomass of Central African Tree Species: The Simple Choice of the Outer Wood.

Directory of Open Access Journals (Sweden)

Jean-François Bastin

Full Text Available Wood specific gravity is a key element in tropical forest ecology. It integrates many aspects of tree mechanical properties and functioning and is an important predictor of tree biomass. Wood specific gravity varies widely among and within species and also within individual trees. Notably, contrasted patterns of radial variation of wood specific gravity have been demonstrated and related to regeneration guilds (light demanding vs. shade-bearing. However, although being repeatedly invoked as a potential source of error when estimating the biomass of trees, both intraspecific and radial variations remain little studied. In this study we characterized detailed pith-to-bark wood specific gravity profiles among contrasted species prominently contributing to the biomass of the forest, i.e., the dominant species, and we quantified the consequences of such variations on the biomass.Radial profiles of wood density at 8% moisture content were compiled for 14 dominant species in the Democratic Republic of Congo, adapting a unique 3D X-ray scanning technique at very high spatial resolution on core samples. Mean wood density estimates were validated by water displacement measurements. Wood density profiles were converted to wood specific gravity and linear mixed models were used to decompose the radial variance. Potential errors in biomass estimation were assessed by comparing the biomass estimated from the wood specific gravity measured from pith-to-bark profiles, from global repositories, and from partial information (outer wood or inner wood.Wood specific gravity profiles from pith-to-bark presented positive, neutral and negative trends. Positive trends mainly characterized light-demanding species, increasing up to 1.8 g.cm-3 per meter for Piptadeniastrum africanum, and negative trends characterized shade-bearing species, decreasing up to 1 g.cm-3 per meter for Strombosia pustulata. The linear mixed model showed the greater part of wood specific gravity

Wood Specific Gravity Variations and Biomass of Central African Tree Species: The Simple Choice of the Outer Wood.

Science.gov (United States)

Bastin, Jean-François; Fayolle, Adeline; Tarelkin, Yegor; Van den Bulcke, Jan; de Haulleville, Thales; Mortier, Frederic; Beeckman, Hans; Van Acker, Joris; Serckx, Adeline; Bogaert, Jan; De Cannière, Charles

2015-01-01

Wood specific gravity is a key element in tropical forest ecology. It integrates many aspects of tree mechanical properties and functioning and is an important predictor of tree biomass. Wood specific gravity varies widely among and within species and also within individual trees. Notably, contrasted patterns of radial variation of wood specific gravity have been demonstrated and related to regeneration guilds (light demanding vs. shade-bearing). However, although being repeatedly invoked as a potential source of error when estimating the biomass of trees, both intraspecific and radial variations remain little studied. In this study we characterized detailed pith-to-bark wood specific gravity profiles among contrasted species prominently contributing to the biomass of the forest, i.e., the dominant species, and we quantified the consequences of such variations on the biomass. Radial profiles of wood density at 8% moisture content were compiled for 14 dominant species in the Democratic Republic of Congo, adapting a unique 3D X-ray scanning technique at very high spatial resolution on core samples. Mean wood density estimates were validated by water displacement measurements. Wood density profiles were converted to wood specific gravity and linear mixed models were used to decompose the radial variance. Potential errors in biomass estimation were assessed by comparing the biomass estimated from the wood specific gravity measured from pith-to-bark profiles, from global repositories, and from partial information (outer wood or inner wood). Wood specific gravity profiles from pith-to-bark presented positive, neutral and negative trends. Positive trends mainly characterized light-demanding species, increasing up to 1.8 g.cm-3 per meter for Piptadeniastrum africanum, and negative trends characterized shade-bearing species, decreasing up to 1 g.cm-3 per meter for Strombosia pustulata. The linear mixed model showed the greater part of wood specific gravity variance was

Specific Modulus and Density Profile as Characterization Criteria of Prefabricated Wood Composite Materials

Directory of Open Access Journals (Sweden)

Pavel Král

2015-01-01

Full Text Available Wood based product industry has developed and modified a wide range of products to cater changing demands of construction industry. Development of a product necessitates characterization to ensure compliance to established standards. Traditionally a product was characterized by properties like bending properties, density and swelling factor etc. Whereas, advances in technology has introduced more sophisticated parameters which represent a combination of various classical factors and provide more practical and detailed information. In this study, we procured four different types of commercial products, viz. Gypsum board, cement board, oriented strand board and gypsum fiber board and tried to characterized them using density profile ratio and stiffness ratio. We observed some interesting empirical relations between various parameters as represented in various plots.

Development of indirect ring tension test for fracture characterization of asphalt mixtures

Science.gov (United States)

Zeinali Siavashani, Alireza

Low temperature cracking is a major distress in asphalt pavements. Several test configurations have been introduced to characterize the fracture properties of hot mix (HMA); however, most are considered to be research tools due to the complexity of the test methods or equipment. This dissertation describes the development of the indirect ring tension (IRT) fracture test for HMA, which was designed to be an effective and user-friendly test that could be deployed at the Department of Transportation level. The primary advantages of this innovative and yet practical test include: relatively large fracture surface test zone, simplicity of the specimen geometry, widespread availability of the required test equipment, and ability to test laboratory compacted specimens as well as field cores. Numerical modeling was utilized to calibrate the stress intensity factor formula of the IRT fracture test for various specimen dimensions. The results of this extensive analysis were encapsulated in a single equation. To develop the test procedure, a laboratory study was conducted to determine the optimal test parameters for HMA material. An experimental plan was then developed to evaluate the capability of the test in capturing the variations in the mix properties, asphalt pavement density, asphalt material aging, and test temperature. Five plant-produced HMA mixtures were used in this extensive study, and the results revealed that the IRT fracture test is highly repeatable, and capable of capturing the variations in the fracture properties of HMA. Furthermore, an analytical model was developed based on the viscoelastic properties of HMA to estimate the maximum allowable crack size for the pavements in the experimental study. This analysis indicated that the low-temperature cracking potential of the asphalt mixtures is highly sensitive to the fracture toughness and brittleness of the HMA material. Additionally, the IRT fracture test data seemed to correlate well with the data from

Optics in the preservation of cultural heritage. Micro topographic and rugometric evaluation of wood artifacts

International Nuclear Information System (INIS)

Costa, Manuel F. M.

2009-01-01

Optics and optical techniques and instruments are long time being successfully employed in the preservation of cultural heritage: both in cleaning and reconstruction but especially in inspection and noninvasive diagnosis. Humankind cultural heritage includes a vast number and variety of wood objects and artefacts. The inspection and characterization of the surface of wood artefacts and structures is very important for registering its status and in evaluating how it evolves when subjected to a certain kind of environmental constraint, or in the defining the suitability of a certain kind of material for a specific application. Both 2D and microtopographic inspection should be performed extensively and in a oninvasive way. For several years we have developed a series of active optical triangulation based microtopographers, the MICROTOP' family, improved and adapted according to particular inspection needs. Currently five system are available: the main system the MICROTOP.03.MFC intended for general use on the inspection of rough surfaces (both 2D and 3D) ; the PL system is a simplified version used on the inspection of polymer pieces and materials; a version to be used on the automotive industry for real time detection of fracture conditions in structural pieces; a simple hand held version; and the version .06 adapted by incorporation of an angle resolved scattering structure with height resolution measuring capabilities down to the nanometer range is the latest and more versatile version. The inspection of wood surfaces is successfully performed using the MICROTOP systems even when painted wood or 'talha dourada' gold engraved wood is involved. The three-dimensional evaluation is complemented by 2D image acquisition and processing, and by rugometric characterization making available all available ISO parameters and a reduced set of statistical parameters and function more meaningful on this kind of application. Also this set is adjusted to the particular

Characterization of the fracturation of rock masses for determining flow

International Nuclear Information System (INIS)

Derlich, S.

1984-02-01

Flow in a rock mass is the consequence of the permeability of the rock, which can be roughly separated into matrix permeability and fissure permeability. In crystalline rocks fissure permeability is dominant, especially where the rocks are extensively fractured. It is thus essential, by means of studies either at the surface or underground, to characterize the volume fracturation in the mass considered. The purpose of this paper is to illustrate the methodology for analysing fracturation at a site by the studies performed on the granite mass of Auriat in the French Massif Central. A number of geology laboratories have participated in this study and a broad spectrum of observations has been made which can be used for determining the various stages of a study with a view to selection of a site, the advantages and limitations of each method or study plan and additional methods which need to be used for gaining as complete a picture as possible of the fracturation. A brief examination of the results obtained at Auriat enables the relative advantages of using these various methods at a particular site to be compared

Innovations in the characterization of fractured rocks developed within the Stripa project

International Nuclear Information System (INIS)

Black, J.; Brightman, M.; Holmes, D.

1994-01-01

This text deals with the hydrogeological work that has been carried out at Stripa Mine. First of all, the philosophy applied evolved through the years, and has finally been focused on a fractured rock approach. Second, it has been necessary to develop hydraulic testing methods - such as focused packer testing - and equipment; the key of the success of the equipment that was built, was that it was fully computer controlled and able to regulate water pressures quickly, reliably and accurately. In the end, the aim of the hydrogeological testing was to characterize both the small scale fracture network and the large scale major fracture zone which composed the site. (TEC). 13 refs., 5 figs

In situ 3D characterization of historical coatings and wood using multimodal nonlinear optical microscopy.

Science.gov (United States)

Latour, Gaël; Echard, Jean-Philippe; Didier, Marie; Schanne-Klein, Marie-Claire

2012-10-22

We demonstrate multimodal nonlinear optical imaging of historical artifacts by combining Second Harmonic Generation (SHG) and Two-Photon Excited Fluorescence (2PEF) microscopies. We first identify the nonlinear optical response of materials commonly encountered in coatings of cultural heritage artifacts by analyzing one- and multi-layered model samples. We observe 2PEF signals from cochineal lake and sandarac and show that pigments and varnish films can be discriminated by exploiting their different emission spectral ranges as in luminescence linear spectroscopy. We then demonstrate SHG imaging of a filler, plaster, composed of bassanite particles which exhibit a non centrosymmetric crystal structure. We also show that SHG/2PEF imaging enables the visualization of wood microstructure through typically 60 µm-thick coatings by revealing crystalline cellulose (SHG signal) and lignin (2PEF signal) in the wood cell walls. Finally, in situ multimodal nonlinear imaging is demonstrated in a historical violin. SHG/2PEF imaging thus appears as a promising non-destructive and contactless tool for in situ 3D investigation of historical coatings and more generally for wood characterization and coating analysis at micrometer scale.

Application of small specimens to fracture mechanics characterization of irradiated pressure vessel steels

International Nuclear Information System (INIS)

Sokolov, M.A.; Wallin, K.; McCabe, D.E.

1996-01-01

In this study, precracked Charpy V-notch (PCVN) specimens were used to characterize the fracture toughness of unirradiated and irradiated reactor pressure vessel steels in the transition region by means of three-point static bending. Fracture toughness at cleavage instability was calculated in terms of elastic-plastic K Jc values. A statistical size correction based upon weakest-link theory was performed. The concept of a master curve was applied to analyze fracture toughness properties. Initially, size-corrected PCVN data from A 533 grade B steel, designated HSST Plate O2, were used to position the master curve and a 5% tolerance bound for K Jc data. By converting PCVN data to IT compact specimen equivalent K Jc data, the same master curve and 5% tolerance bound curve were plotted against the Electric Power Research Institute valid linear-elastic K Jc database and the ASME lower bound K Ic curve. Comparison shows that the master curve positioned by testing several PCVN specimens describes very well the massive fracture toughness database of large specimens. These results give strong support to the validity of K Jc with respect to K Ic in general and to the applicability of PCVN specimens to measure fracture toughness of reactor vessel steels in particular. Finally, irradiated PCVN specimens of other materials were tested, and the results are compared to compact specimen data. The current results show that PCVNs demonstrate very good capacity for fracture toughness characterization of reactor pressure vessel steels. It provides an opportunity for direct measurement of fracture toughness of irradiated materials by means of precracking and testing Charpy specimens from surveillance capsules. However, size limits based on constraint theory restrict the operational test temperature range for K Jc data from PCVN specimens. 13 refs., 8 figs., 1 tab

Characterization of Cypress Wood for Kraft Pulp Production

Directory of Open Access Journals (Sweden)

António J. A. Santos

2014-06-01

Full Text Available Wood samples of Cupressus arizonica, C. lusitanica, and C. sempervirens were evaluated for chemical, anatomical, and pulp characteristics as raw material for pulp production. Two 17-year-old trees per species were harvested, and wood samples were taken at a height of 2 m. Wood chips from Pinus pinaster (Portugal and P. sylvestris (Finland were used as references. C. arizonica differed from C. lusitanica and C. sempervirens with significantly lower (p < 0.05 tracheid diameter and wall thickness in the earlywood. The total extractives contents were 3.9%, 3.3%, and 2.5% for C. lusitanica, C. sempervirens, and C. arizonica, respectively, lower than the 5.1% for P. pinaster and 4.5% for P. sylvestris. Klason lignin content ranged from 33.0 to 35.6%, higher than the 28.0 to 28.7% for the pinewoods. The kraft pulp yields for C. arizonica, C. lusitanica, and C. sempervirens were 37.7%, 36.7%, and 38.7%, respectively, with kappa numbers of 32.0, 31.6, and 28.7, respectively; the yield values were 40.8% and 42.8%, with kappa numbers of 23.4 and 21.0, for P. pinaster and P. sylvestris, respectively. The cypress species are clearly different from pine in relation to wood pulping behavior. Among the cypress, C. sempervirens provided the best pulping results.

Analog site for fractured rock characterization. Annual report FY 1995

International Nuclear Information System (INIS)

Long, J.C.S.; Loughty, C.; Faybishenko, B.

1995-10-01

This report describes the accomplishments of the Analog Site for Fracture Rock Characterization Project during fiscal year 1995. This project is designed to address the problem of characterizing contaminated fractured rock. In order to locate contaminant plumes, develop monitoring schemes, and predict future fate and transport, the project will address the following questions: What parts of the system control flow-geometry of a fracture network? What physical processes control flow and transport? What are the limits on measurements to determine the above? What instrumentation should be used? How should it be designed and implemented? How can field tests be designed to provide information for predicting behavior? What numerical models are good predictors of the behavior of the system? The answers to these question can be used to help plan drilling programs that are likely to intersect plumes and provide effective monitoring of plume movement. The work is done at an open-quotes analogueclose quotes site, i.e., a site that is not contaminated, but has similar geology to sites that are contaminated, in order to develop tools and techniques without the financial, time and legal burdens of a contaminated site. The idea is to develop conceptual models and investigations tools and methodology that will apply to the contaminated sites in the same geologic regimes. The Box Canyon site, chosen for most of this work represents a unique opportunity because the Canyon walls allow us to see a vertical plane through the rock. The work represents a collaboration between the Lawrence Berkeley National Laboratory (LBL), Stanford University (Stanford), Idaho National Engineering Laboratory (INEL) and Parsons Environmental Engineering (Parsons). LBL and Stanford bring extensive experience in research in fractured rock systems. INEL and Parsons bring significant experience with the contamination problem at INEL

Fracture characterization and discrimination criteria for karst and tectonic fractures in the Ellenburger Group, West Texas: Implications for reservoir and exploration models

Energy Technology Data Exchange (ETDEWEB)

Hoak, T.E. [Science Applications International Corp., Germantown, MD (United States)]|[Kestrel Geoscience, Littleton, CO (United States); Sundberg, K.R. [Phillips Petroleum Co., Bartlesville, OK (United States); Deyhim, P. [Oklahoma State Univ., Stillwater, OK (United States); Ortoleva, P. [Indiana Univ., Bloomington, IN (United States). Lab. for Computational Geodynamics

1998-12-31

In the Ellenburger Group fractured dolomite reservoirs of West Texas, it is extremely difficult to distinguish between multiple phases of karst-related fracturing, modifications to the karst system during burial, and overprinting tectonic fractures. From the analyses of drill core, the authors developed criteria to distinguish between karst and tectonic fractures. In addition, they have applied these criteria within the context of a detailed diagenetic cement history that allows them to further refine the fracture genesis and chronology. In these analyses, the authors evaluated the relationships between fracture intensity, morphologic attributes, host lithology, fracture cement, and oil-staining. From this analysis, they have been able to characterize variations in Ellenburger tectonic fracture intensity by separating these fractures from karst-related features. In general, the majority of fracturing in the Ellenburger is caused by karst-related fracturing although a considerable percentage is caused by tectonism. These findings underscore the importance of considering the complete geologic evolution of a karst reservoir during exploration and field development programs. The authors have been able to more precisely define the spatial significance of the fracture data sets by use of oriented core from Andector Field. They have also demonstrated the importance of these results for exploration and reservoir development programs in West Texas, and the potential to extrapolate these results around the globe. Given the historic interest in the large hydrocarbon reserves in West Texas carbonate reservoirs, results of this study will have tremendous implications for exploration and production strategies targeting vuggy, fractured carbonate systems not only in West Texas, but throughout the globe.

Characterization of Fractured Reservoirs Using a Combination of Downhole Pressure and Self-Potential Transient Data

OpenAIRE

Yuji Nishi; Tsuneo Ishido

2012-01-01

In order to appraise the utility of self-potential (SP) measurements to characterize fractured reservoirs, we carried out continuous SP monitoring using multi Ag-AgCl electrodes installed within two open holes at the Kamaishi Mine, Japan. The observed ratio of SP change to pressure change associated with fluid flow showed different behaviors between intact host rock and fractured rock regions. Characteristic behavior peculiar to fractured reservoirs, which is predicted from numerical simulati...

Use of integrated geologic and geophysical information for characterizing the structure of fracture systems at the US/BK Site, Grimsel Laboratory, Switzerland

International Nuclear Information System (INIS)

Martel, S.J.; Peterson, J.E. Jr.

1990-05-01

Fracture systems form the primary fluid flow paths in a number of rock types, including some of those being considered for high level nuclear waste repositories. In some cases, flow along fractures must be modeled explicitly as part of a site characterization effort. Fractures commonly are concentrated in fracture zones, and even where fractures are seemingly ubiquitous, the hydrology of a site can be dominated by a few discrete fracture zones. We have implemented a site characterization methodology that combines information gained from geophysical and geologic investigations. The general philosophy is to identify and locate the major fracture zones, and then to characterize their systematics. Characterizing the systematics means establishing the essential and recurring patterns in which fractures are organized within the zones. We make a concerted effort to use information on the systematics of the fracture systems to link the site-specific geologic, borehole and geophysical information. This report illustrates how geologic and geophysical information on geologic heterogeneities can be integrated to guide the development of hydrologic models. The report focuses on fractures, a particularly common type of geologic heterogeneity. However, many aspects of the methodology we present can be applied to other geologic heterogeneities as well. 57 refs., 40 figs., 1 tab

Demonstration of a Fractured Rock Geophysical Toolbox (FRGT) for Characterization and Monitoring of DNAPL Biodegradation in Fractured Rock Aquifers

Science.gov (United States)

2015-09-29

is characterized by dark gray slate or phyllite, alternating with thin layers of light gray siltstone or sandstone . Table 1 summarizes the primary...sedimentary rocks of the Newark Basin. Competent rocks are primarily mudstones and sandstones of the Lockatong and Stockton Formations. Fill, weathered silt... sandstone , and characterized by water bearing bedding plane fractures. An array of open boreholes in the source area that were drilled for the 2002

Characterizing fractures and shear zones in crystalline rock using seismic and GPR methods

Science.gov (United States)

Doetsch, Joseph; Jordi, Claudio; Laaksonlaita, Niko; Gischig, Valentin; Schmelzbach, Cedric; Maurer, Hansruedi

2016-04-01

Understanding the natural or artificially created hydraulic conductivity of a rock mass is critical for the successful exploitation of enhanced geothermal systems (EGS). The hydraulic response of fractured crystalline rock is largely governed by the spatial organization of permeable fractures. Defining the 3D geometry of these fractures and their connectivity is extremely challenging, because fractures can only be observed directly at their intersections with tunnels or boreholes. Borehole-based and tunnel-based ground-penetrating radar (GPR) and seismic measurements have the potential to image fractures and other heterogeneities between and around boreholes and tunnels, and to monitor subtle time-lapse changes in great detail. We present the analysis of data acquired in the Grimsel rock laboratory as part of the In-situ Stimulation and Circulation (ISC) experiment, in which a series of stimulation experiments have been and will be performed. The experiments in the granitic rock range from hydraulic fracturing to controlled fault-slip experiments. The aim is to obtain a better understanding of coupled seismo-hydro-mechanical processes associated with high-pressure fluid injections in crystalline rocks and their impact on permeability creation and enhancement. GPR and seismic data have been recorded to improve the geological model and characterize permeable fractures and shear zones. The acquired and processed data include reflection GPR profiles measured from tunnel walls, single-borehole GPR images, and borehole-to-borehole and tunnel-to-tunnel seismic and GPR tomograms. The reflection GPR data reveal the geometry of shear zones up to a distance of 30 m from the tunnels and boreholes, but the interpretation is complicated by the geometrical ambiguity around tunnels and boreholes and by spurious reflections from man-made structures such as boreholes. The GPR and seismic traveltime tomography results reveal brittle fractured rock between two ductile shear zones. The

Delineating pMDI model reactions with loblolly pine via solution-state NMR spectroscopy. Part 1, Catalyzed reactions with wood models and wood polymers

Science.gov (United States)

Daniel J. Yelle; John Ralph; Charles R. Frihart

2011-01-01

To better understand adhesive interactions with wood, reactions between model compounds of wood and a model compound of polymeric methylene diphenyl diisocyanate (pMDI) were characterized by solution-state NMR spectroscopy. For comparison, finely ground loblolly pine sapwood, milled-wood lignin and holocellulose from the same wood were isolated and derivatized with...

Characterization on the Fracture system in jurassic granitic rocks: Kosung and Yusung areas

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyung Su; Bae, Dae Seok; Kim, Chun Soo; Park, Byung Yoon; Koh, Yong Kweon

2001-03-01

The safety of waste disposal can be achieved by a complete isolation of radioactive wastes from biosphere or by a retardation of nuclide migration to reach an acceptable dose level. For the deep geological disposal of high-level radioactive waste, the potential pathways of nuclide primarily depend on the spatial distribution characteristics of conductive fractures in rock mass. Major key issues in the quantification of fracture system for a disposal site are involved in classification criteria, hydraulic parameters, geometry, field investigation methods etc. This research aims to characterize the spatial distribution characteristics of regional lineaments and background fractures in eastern and western-type granite rock mass.

Characterization on the Fracture system in jurassic granitic rocks: Kosung and Yusung areas

International Nuclear Information System (INIS)

Kim, Kyung Su; Bae, Dae Seok; Kim, Chun Soo; Park, Byung Yoon; Koh, Yong Kweon

2001-03-01

The safety of waste disposal can be achieved by a complete isolation of radioactive wastes from biosphere or by a retardation of nuclide migration to reach an acceptable dose level. For the deep geological disposal of high-level radioactive waste, the potential pathways of nuclide primarily depend on the spatial distribution characteristics of conductive fractures in rock mass. Major key issues in the quantification of fracture system for a disposal site are involved in classification criteria, hydraulic parameters, geometry, field investigation methods etc. This research aims to characterize the spatial distribution characteristics of regional lineaments and background fractures in eastern and western-type granite rock mass

Characterization of Fractures in the Chicxulub Peak Ring: Preliminary Results from IODP/ICDP Expedition 364

Science.gov (United States)

McCall, N.; Gulick, S. P. S.; Morgan, J. V.; Hall, B. J.; Jones, L.; Expedition 364 Science Party, I. I.

2017-12-01

During Expedition 364, IODP/ICDP drilled the peak ring of the Chicxulub impact crater at Site M0077, recovering core from 505.7 to 1334.7 mbsf. The core has been imaged via X-ray Computer Tomography (CT) as a noninvasive method to create a 3-dimensional model of the core, providing information on the density and internal structure at a 0.3 mm resolution. Results from the expedition show that from 748 mbsf and deeper the peak ring is largely composed of uplifted and fractured granitic basement rocks originally sourced from approximately 8-10 km depth. Impact crater modeling suggests the peak ring was formed through dynamic collapse of a rebounding central peak within 10 minutes of impact, requiring the target rocks to temporarily behave as a viscous fluid. The newly recovered core provides a rare opportunity to investigate the cratering process, specifically how the granite was weakened, as well as the extent of the hydrothermal system created after the impact. Based on the CT data, we identify four classes of fractures based on their CT facies deforming the granitoids: pervasive fine fractures, discrete fine fractures, discrete filled fractures, and discrete open fractures. Pervasive fine fractures were most commonly found proximal to dikes and impact melt rock. Discrete filled fractures often displayed a cataclastic texture. We present density trends for the different facies and compare these to petrophysical properties (density, NGR, P-wave seismic velocity). Fractured areas have a lower density than the surrounding granite, as do most filled fractures. This reduction suggests that fluid migrating through the peak ring in the wake of the impact either deposited lower density minerals within the fractures and/or altered the original fracture fill. The extent and duration of fluid flow recorded in these fractures will assist in the characterization of the post-impact hydrothermal system. Future work includes combining information from CT images with thin sections

Uncertainty Characterization of Reactor Vessel Fracture Toughness

International Nuclear Information System (INIS)

Li, Fei; Modarres, Mohammad

2002-01-01

To perform fracture mechanics analysis of reactor vessel, fracture toughness (K Ic ) at various temperatures would be necessary. In a best estimate approach, K Ic uncertainties resulting from both lack of sufficient knowledge and randomness in some of the variables of K Ic must be characterized. Although it may be argued that there is only one type of uncertainty, which is lack of perfect knowledge about the subject under study, as a matter of practice K Ic uncertainties can be divided into two types: aleatory and epistemic. Aleatory uncertainty is related to uncertainty that is very difficult to reduce, if not impossible; epistemic uncertainty, on the other hand, can be practically reduced. Distinction between aleatory and epistemic uncertainties facilitates decision-making under uncertainty and allows for proper propagation of uncertainties in the computation process. Typically, epistemic uncertainties representing, for example, parameters of a model are sampled (to generate a 'snapshot', single-value of the parameters), but the totality of aleatory uncertainties is carried through the calculation as available. In this paper a description of an approach to account for these two types of uncertainties associated with K Ic has been provided. (authors)

Experimental characterization and modelling of the alteration of fractured cement under CO2 storage conditions

International Nuclear Information System (INIS)

Abdoulghafour, Halidi

2012-01-01

The main purpose of this thesis was to characterize and to model the hydrodynamic and thermochemical processes leading to the alteration of the wellbore cement materials under borehole conditions. Percolation experiments were performed on fractured cement samples under CO 2 storage conditions (60 C and 10 MPa). Injection flow rate was dictated by the fracture aperture of each sample. CO 2 enriched brine was flowed along the fracture aperture, and permeability changes as well as chemical evolution of major cations were continuously acquired during the experiment time. Reaction paths developed by the alteration of the cement were characterized using microtomography and ESEM images. The experiments conducted using samples presenting large fracture apertures during 5 h showed that permeability was maintained constant during the experiment time. Three reacted layers were displaying by the alteration of portlandite and CSH. Long term experiment (26 h) conducted with large initial fracture aperture showed a decrease of the permeability after 15 hours of CO 2 exposure. Otherwise, experiments performed on samples presenting narrow apertures indicated the conversion of portlandite and CSH to calcite leading to the permeability reduction and the fracture clogging. Assemblages of phases and chemical changes were modelled using GEMS-PSI speciation code. We studied also using a coupled transport-reactive model the conditions leading to the cement alteration and the formation of associated layers. (author)

INCIDENCE AND CHARACTERIZATION OF ELDERLY IN THE ORTHOPEDIC CLINIC FOR FEMUR FRACTURE, CACERES MT

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Andréia Costa Ferreira

2013-05-01

Full Text Available Introduction:The elderly population is growing gradually in recent years, it increases theincidence of elderly people at risk of falls and hip fractures develop.Objective:To identifythe incidence and characterize elderly patients hospitalized with hip fractures in theOrthopedic Clinic of the Hospital Regional Dr º Antonio Cáceres sources.Methodology:Thisis an epidemiological, descriptive, quantitative and retrospective data collection documentbasis. The study population comprised 105.Results:It was found that the fracture of thefemur showed predominance in females, comprising 40.90% of the cases and the right lowerlimb most affected. As for location, the trochanteric fractures showed 39.04%, followed byfractures of the femoral shaftwith 27.61% of the cases. The treatment applied in 62.85% ofpatients went to surgery.Conclusion:It is concluded that the femur fracture may preclude theelderly in their daily activities.

Characterization of wood dust from furniture by scanning electron microscopy and energy-dispersive x-ray analysis.

Science.gov (United States)

Gómez Yepes, Milena Elizabeth; Cremades, Lázaro V

2011-01-01

Study characterized and analyzed form factor, elementary composition and particle size of wood dust, in order to understand its harmful health effects on carpenters in Quindío (Colombia). Once particle characteristics (size distributions, aerodynamic equivalent diameter (D(α)), elemental composition and shape factors) were analyzed, particles were then characterized via scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray analysis (EDXRA). SEM analysis of particulate matter showed: 1) cone-shaped particle ranged from 2.09 to 48.79 µm D(α); 2) rectangular prism-shaped particle from 2.47 to 72.9 µm D(α); 3) cylindrically-shaped particle from 2.5 to 48.79 µm D(α); and 4) spherically-shaped particle from 2.61 to 51.93 µm D(α). EDXRA reveals presence of chemical elements from paints and varnishes such as Ca, K, Na and Cr. SEM/EDXRA contributes in a significant manner to the morphological characterization of wood dust. It is obvious that the type of particles sampled is a complex function of shapes and sizes of particles. Thus, it is important to investigate the influence of particles characteristics, morphology, shapes and D(α) that may affect the health of carpenters in Quindío.

Colorimetric characterization of three wood species from the amazon forest

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Sâmia Valéria dos Santos Barros

2014-09-01

Full Text Available The aim of this study was to analyze wood color variability in the (radial, tangential and transversal anatomic sections of Breu-vermelho, Tauari-vermelho and Pequiarana species through quantitative colorimetry using CIELAB color system. Such species come from a forest sustainable area of Thousand Precious Woods Company, located in Itacoatiara in the Amazon region of Brazil. Five wood samples from each species were selected so as to determine the following colorimetric parameters: L*, a*, b*, C e h*. In addition, 225 measurements were carried out with Konica Minolta CM-5 spectrophotometer connected to the computer. Results pointed out to statistical differences in the colorimetric parameters and also a low saturation in a* in the analyzed species. According to the cluster gathering, Breu-vermelho wood presents olive and/or grayish pink color, Tauari-vermelho is pinkish-gray and Pequiarana is grayish-pink and/or pinkish-gray. Such species presented differences in color among the three anatomic sections cited above and were also influenced by the yellow color defined in b* parameter. To summarize, colorimetric analysis to establish wood color is a simple procedure which may be used from the sawing of the logs until their final exploitation enabling value aggregation to the final product.

Natural Fractures Characterization and In Situ Stresses Inference in a Carbonate Reservoir—An Integrated Approach

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Ali Shafiei

2018-02-01

Full Text Available In this paper, we characterized the natural fracture systems and inferred the state of in situ stress field through an integrated study in a very complex and heterogeneous fractured carbonate reservoir. Relative magnitudes and orientations of the in-situ principal stresses in a naturally fractured carbonate heavy oil field were estimated with a combination of available data (World Stress Map, geological and geotectonic evidence, outcrop studies and techniques (core analysis, borehole image logs and Side View Seismic Location. The estimates made here using various tools and data including routine core analysis and image logs are confirmatory to estimates made by the World Stress Map and geotectonic facts. NE-SW and NW-SE found to be the dominant orientations for maximum and minimum horizontal stresses in the study area. In addition, three dominant orientations were identified for vertical and sub-vertical fractures atop the crestal region of the anticlinal structure. Image logs found useful in recognition and delineation of natural fractures. The results implemented in a real field development and proved practical in optimal well placement, drilling and production practices. Such integrated studies can be instrumental in any E&P projects and related projects such as geological CO2 sequestration site characterization.

CHARACTERIZATION OF WOOD DECAY BY ROT FUNGI USING COLORIMETRY AND INFRARED SPECTROSCOPY

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Mírian de Almeida Costa

2011-09-01

Full Text Available Wood samples of marupá (Simarouba amara and andiroba (Carapa guianenis were submitted to Trametes versicolor (white rot and Gloeophylum trabeum (brown rot fungi attack. Colorimetry was used to determine the color of the wood before and after wood decaying fungi. To evaluate the changes in chemical compounds levels in the wood samples, the diffuse reflectance medium infrared spectroscopy was used. Both wood were non resistant against white rot fungus, while with brown rot attack andiroba was resistant and marupá was not. After Gloeophyllum trabeum attack both woods changed to a darken color, and after Trametes versicolor attack andiroba changed to a lighter color and marupá darkened slightly, The analysis showed a reduction in the peak intensity of cellulose, hemicellulose and lignin, for both species, after Trametes versicolor attack and a reduction in the peak intensity of cellulose after Gloeophyllum trabeum attack.

Dendrological Characterization as Inspection Resources of Caatinga Wood Market

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Rayssa de Medeiros Morais

2018-06-01

Full Text Available ABSTRACT This study aimed to distinguish five native forest species of the Caatinga Biome from the exotic invasive algaroba (Prosopis juliflora (Sw. DC., considering dendrologic characteristics of bark and wood, in order of providing subsidies for the inspection of the wood market in this Biome. The native species studied were jurema-preta (Mimosa tenuiflora (Willd. Poir., angico branco (Anadenanthera colubrina var. colubrina (Vell. Brenan, angico vermelho (Anadenanthera colubrina var. cebil (Gris. Alts., aroeira (Myracrodruon urundeuva Allem and braúna-do-sertão (Schinopsis brasiliensis Engl.. Studied species were recognized using dendrology identification records, containing characteristics of bark, heartwood and sapwood coloration; and the organoleptic proprieties like color, smell and taste, used for safe wood logs identification. The macroscopic characteristics, organized in dichotomous key, allowed the differentiation among the species, available in logs, during inspection.

Characterization of wood polymer composite and design of root trainer

Science.gov (United States)

Chitra, K. N.; Abhilash, R. M.; Chauhan, Shakti Singh; Venkatesh, G. S.; Shivkumar, N. D.

2018-04-01

Biopolymers have received much attention of researchers due to concerns over disposal of plastics, greenhouse gas emission and environmental problems associated with it. Polylactic Acid (PLA) is one of the thermoplastic biopolymer made from lactic acid by using agricultural resources. PLA has received significant interest due to its competitive properties when compared to commodity plastics such as Polyethylene, Polypropylene and Polystyrene. PLA has interesting properties such as high stiffness, UV stability, clear and glossy finish. However, application of PLA is restricted due to its brittle nature. Engineering and thermal properties of PLA can be improved by reinforcing fibres and fillers. Lignocelluloses or natural fibres such as Jute, Hemp, Bamboo, Sisal and Wood fibres can be used as reinforcement. By using natural fibres, a very bio-compostable composite can be produced. In the present study, short fibres from Melia Dubia wood were extracted and used as reinforcement to PLA Bio-Polymer matrix. Characterization of developed composite was obtained using tensile and flexural tests. Tensile test simulation of composite was performed using Altair Hypermesh, a Finite Element (FE) preprocessor and LS-Dyna an explicit FE solver. MAT_01, an elastic material model in LS-Dyna was used to model the behaviour. Further, the design of Root Trainer using developed composite has been explored. A Root Trainer is an aid to the cultivation of seedlings in nurseries. Root Trainer made by using developed composite has advantage of biodegradability and eco-friendly nature.

Microstructural characterization, petrophysics and upscaling - from porous media to fractural media

Science.gov (United States)

Liu, J.; Liu, K.; Regenauer-Lieb, K.

2017-12-01

We present an integrated study for the characterization of complex geometry, fluid transport features and mechanical deformation at micro-scale and the upscaling of properties using microtomographic data: We show how to integrate microstructural characterization by the volume fraction, specific surface area, connectivity (percolation), shape and orientation of microstructures with identification of individual fractures from a 3D fractural network. In a first step we use stochastic analyses of microstructures to determine the geometric RVE (representative volume element) of samples. We proceed by determining the size of a thermodynamic RVE by computing upper/lower bounds of entropy production through Finite Element (FE) analyses on a series of models with increasing sizes. The minimum size for thermodynamic RVE's is identified on the basis of the convergence criteria of the FE simulations. Petrophysical properties (permeability and mechanical parameters, including plastic strength) are then computed numerically if thermodynamic convergence criteria are fulfilled. Upscaling of properties is performed by means of percolation theory. The percolation threshold is detected by using a shrinking/expanding algorithm on static micro-CT images of rocks. Parameters of the scaling laws can be extracted from quantitative analyses and/or numerical simulations on a series of models with similar structures but different porosities close to the percolation threshold. Different rock samples are analyzed. Characterizing parameters of porous/fractural rocks are obtained. Synthetic derivative models of the microstructure are used to estimate the relationships between porosity and mechanical properties. Results obtained from synthetic sandstones show that yield stress, cohesion and the angle of friction are linearly proportional to porosity. Our integrated study shows that digital rock technology can provide meaningful parameters for effective upscaling if thermodynamic volume averaging

Example of fracture characterization in granitic rock

International Nuclear Information System (INIS)

Thorpe, R.K.

1981-03-01

A detailed study of geologic discontinuities for an underground heater test in highly fractured granitic rock is reported. Several prominent shear fractures were delineated within a 6 x 30 x 15 m rock mass by correlating surface mapping and borehole fracture logs. Oblique-reverse faulting is suspected on at least one of the surfaces, and its inferred borehole intercepts appear to be collinear in the direction of slickensiding observed in the field. Four distinct joint sets were identified, one of which coincides with the shear fractures. Another lies nearly horizontal, and two others are steeply inclined and orthogonal. Fracture lengths and spacings for the four joint sets are represented by lognormal probability distributions

Characterization of reservoir fractures using conventional geophysical logging

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Paitoon Laongsakul

2011-04-01

Full Text Available In hydrocarbon exploration fractures play an important role as possible pathways for the hydrocarbon flow and bythis enhancing the overall formation’s permeability. Advanced logging methods for fracture analysis, like the boreholeacoustic televiewer and Formation Microscanner (FMS are available, but these are additional and expensive tools. However,open and with water or hydrocarbon filled fractures are also sensitive to electrical and other conventional logging methods.For this study conventional logging data (electric, seismic, etc were available plus additional fracture information from FMS.Taking into account the borehole environment the results show that the micro-spherically focused log indicates fractures byshowing low resistivity spikes opposite open fractures, and high resistivity spikes opposite sealed ones. Compressional andshear wave velocities are reduced when passing trough the fracture zone, which are assumed to be more or less perpendicularto borehole axis. The photoelectric absorption curve exhibit a very sharp peak in front of a fracture filled with bariteloaded mud cake. The density log shows low density spikes that are not seen by the neutron log, usually where fractures,large vugs, or caverns exist. Borehole breakouts can cause a similar effect on the logging response than fractures, but fracturesare often present when this occurs. The fracture index calculation by using threshold and input weight was calculatedand there was in general a good agreement with the fracture data from FMS especially in fracture zones, which mainlycontribute to the hydraulic system of the reservoir. Finally, the overall results from this study using one well are promising,however further research in the combination of different tools for fracture identification is recommended as well as the useof core for further validation.

Cell-wall recovery after irreversible deformation of wood

Science.gov (United States)

Keckes, Jozef; Burgert, Ingo; Frühmann, Klaus; Müller, Martin; Kölln, Klaas; Hamilton, Myles; Burghammer, Manfred; Roth, Stephan V.; Stanzl-Tschegg, Stefanie; Fratzl, Peter

2003-12-01

The remarkable mechanical properties of biological materials reside in their complex hierarchical architecture and in specific molecular mechanistic phenomena. The fundamental importance of molecular interactions and bond recovery has been suggested by studies on deformation and fracture of bone and nacre. Like these mineral-based materials, wood also represents a complex nanocomposite with excellent mechanical performance, despite the fact that it is mainly based on polymers. In wood, however, the mechanistic contribution of processes in the cell wall is not fully understood. Here we have combined tensile tests on individual wood cells and on wood foils with simultaneous synchrotron X-ray diffraction analysis in order to separate deformation mechanisms inside the cell wall from those mediated by cell-cell interactions. We show that tensile deformation beyond the yield point does not deteriorate the stiffness of either individual cells or foils. This indicates that there is a dominant recovery mechanism that re-forms the amorphous matrix between the cellulose microfibrils within the cell wall, maintaining its mechanical properties. This stick-slip mechanism, rather like Velcro operating at the nanometre level, provides a 'plastic response' similar to that effected by moving dislocations in metals. We suggest that the molecular recovery mechanism in the cell matrix is a universal phenomenon dominating the tensile deformation of different wood tissue types.

An integrated methodology for characterizing flow and transport processes in fractured rock

International Nuclear Information System (INIS)

Wu, Yu-Shu

2007-01-01

To investigate the coupled processes involved in fluid and heat flow and chemical transport in the highly heterogeneous, unsaturated-zone (UZ) fractured rock of Yucca Mountain, we present an integrated modeling methodology. This approach integrates a wide variety of moisture, pneumatic, thermal, and geochemical isotopic field data into a comprehensive three-dimensional numerical model for modeling analyses. The results of field applications of the methodology show that moisture data, such as water potential and liquid saturation, are not sufficient to determine in situ percolation flux, whereas temperature and geochemical isotopic data provide better constraints to net infiltration rates and flow patterns. In addition, pneumatic data are found to be extremely valuable in estimating large-scale fracture permeability. The integration of hydrologic, pneumatic, temperature, and geochemical data into modeling analyses is thereby demonstrated to provide a practical modeling approach for characterizing flow and transport processes in complex fractured formations

Conceptual characterization of the system of fractures of the rock mass known as Sierra del Medio (Chubut)

International Nuclear Information System (INIS)

Ventura, M.A.

1990-01-01

This work characterizes conceptually the system of fractures of the rock mass known as Sierra del Medio and its surroundings. The purpose of this characterization is to define the spectra of flow regimes which must be covered in computational models to be used in the prediction of the thermohydraulic effects of the eventual emplacement of a high-level radioactive waste repository. The analysis of the available data from previous studies was performed in order to determine qualitative data to be used in the stage of feasibility studied. The flow of water roughly N-S is defined by two systems of vertical, almost orthogonal fractures and surrounded by large faults. A set of hypotheses were considered which allow, supposing a given distribution of surface fractures, to establish the variations according to depth. The usual ways of obtaining the permeability and the hydraulic conductivity in fractured porous media are summarized in an appendix. (Author) [es

Significance of wood extractives for wood bonding.

Science.gov (United States)

Roffael, Edmone

2016-02-01

Wood contains primary extractives, which are present in all woods, and secondary extractives, which are confined in certain wood species. Extractives in wood play a major role in wood-bonding processes, as they can contribute to or determine the bonding relevant properties of wood such as acidity and wettability. Therefore, extractives play an immanent role in bonding of wood chips and wood fibres with common synthetic adhesives such as urea-formaldehyde-resins (UF-resins) and phenol-formaldehyde-resins (PF-resins). Extractives of high acidity accelerate the curing of acid curing UF-resins and decelerate bonding with alkaline hardening PF-resins. Water-soluble extractives like free sugars are detrimental for bonding of wood with cement. Polyphenolic extractives (tannins) can be used as a binder in the wood-based industry. Additionally, extractives in wood can react with formaldehyde and reduce the formaldehyde emission of wood-based panels. Moreover, some wood extractives are volatile organic compounds (VOC) and insofar also relevant to the emission of VOC from wood and wood-based panels.

Fracture-fault network characterization of pavement imagery of the Whitby Mudstone, Yorkshire

Science.gov (United States)

Boersma, Quinten; Hardebol, Nico; Houben, Maartje; Barnhoorn, Auke; Drury, Martyn

2015-04-01

Natural fractures play an important role in the hydrocarbon production from tight reservoirs. The need for fracture network pathways by fraccing matters particularly for shale gas prospects, due to their micro- to nano-darcies matrix permeabilities. The study of natural fractures from outcrops helps to better understand network connectivity and possibility of reactivating pre-existing planes of weakness, induced by hydraulic stimulation. Microseismicity also show that natural fractures are reactivated during fraccing in tight gas reservoirs and influence the success of the stimulation. An accurate understanding of natural fracture networks can help in predicting the development of fracture networks. In this research we analyze an outcrop analogue, the Whitby Mustone Formation (WMF), in terms of its horizontal fracture network. The WMF is the time equivalent of the Posidonia Shale Formation (PSF), which on itself is the main shale gas prospect in the Dutch subsurface. The fracture network of the WMF is characterized by a system of steep dipping joints with two dominant directions with N-S and E-W strike. The network was digitized from bird-view imagery of the pavement with a spatial extent of ~100 m at sub-cm resolution. The imagery is interpreted in terms of orientation and length distributions, intensity and fractal dimensions. Samples from the field were analyzed for rock strength and sample mineralogy. The results indicate that the fracture networks greatly differ per bed. Observed differences are for example; the geometry of the fracture network, its cumulative length distribution law, the fracture intensity, the fracture length vs its orientation and the fractal dimension. All these parameters greatly influence fracture network connectivity, the probability that longer fractures exist within the pavement and whether the network is more prone to clustering or scattering. Apart from the differences, the networks display a fairly similar orthogonal arrangement

Application of borehole geophysics to fracture identification and characterization in low porosity limestones and dolostones

International Nuclear Information System (INIS)

Haase, C.S.; King, H.L.

1986-01-01

Geophysical logging was conducted in exploratory core holes drilled for geohydrological investigations at three sites used for waste disposal on the US Department of Energy's Oak Ridge Reservation. Geophysical log response was calibrated to borehole geology using the drill core. Subsequently, the logs were used to identify fractures and fractured zones and to characterize the hydrologic activity of such zones. Results of the study were used to identify zones of ground water movement and to select targets for subsequent piezometer and monitoring well installation. Neutron porosity, long- and short-normal resistivity, and density logs exhibit anomalies only adjacent to pervasively fractured zones and rarely exhibit anomalies adjacent to individual fractures, suggesting that such logs have insufficient resolution to detect individual fractures. Spontaneous potential, single point resistance, acoustic velocity, and acoustic variable density logs, however, typically exhibit anomalies adjacent to both individual fractures and fracture zones. Correlation is excellent between fracture density logs prepared from the examination of drill core and fractures identified by the analysis of a suite of geophysical logs that have differing spatial resolution characteristics. Results of the study demonstrate the importance of (1) calibrating geophysical log response to drill core from a site, and (2) running a comprehensive suite of geophysical logs that can evaluate both large- and small-scale rock features. Once geophysical log responses to site-specific geological features have been established, logs provide a means of identifying fracture zones and discriminating between hydrologically active and inactive fracture zones. 9 figs

Radiographic and pathologic characterization of lateral palmar intercarpal ligament avulsion fractures in the horse.

Science.gov (United States)

Beinlich, Christopher P; Nixon, Alan J

2004-01-01

In this study, the radiographic and histologic appearance of lateral palmar intercarpal ligament (LPICL) avulsion in the horse was characterized. Thirty-seven horses with radiographic evidence of avulsion fragments originating from the medial palmar aspect of the ulnar carpal bone were examined. The dorsolateral to palmaromedial projection was useful for evaluating the size and shape of the avulsed bone fragment, and the dorsopalmar projection added information on the relative proximity of the fragment to its fracture bed. Radiographic features that differentiated LPICL avulsion from subchondral cystic lesions of the ulnar carpal bone included a variable-sized osseous opacity adjacent to the lucent concavity of the fracture bed and the consistent location within the palmar transition zone at the confluence of LPICL insertion and hyaline cartilage on the palmar surface of the ulnar carpal bone. All 26 horses having surgical removal of the fragments had arthroscopic confirmation that the fragment was within the LPICL. Histologic examination confirmed the fragments were fracture related rather than developmental or the result of dystrophic mineralization. Many of the fragments had attached remnants of a ligament. This study describes the radiographic, surgical, and histologic features in 37 horses which better characterize LPICL avulsion fracture in the carpus and provide differentiating features to assist in separating this syndrome from true osseous cyst-like lesions within the ulnar carpal bone.

HIGH RESOLUTION MICROTOMOGRAPHY FOR DENSITY AND SPATIAL INFORMATION ABOUT WOOD STRUCTURES.

Energy Technology Data Exchange (ETDEWEB)

ILLMAN,B.

1999-07-22

Microtomography has successfully been used to characterize loss of structural integrity of wood. Tomographic images were generated with the newly developed third generation x-ray computed microtomography (XCMT) instrument at the X27A beamline at the National Synchrotron Light Source (NSLS). The beamline is equipped with high-flux x-ray monochromator based on multilayer optics developed for this application. The sample is mounted on a translation stage with which to center the sample rotation, a rotation stage to perform the rotation during data collection and a motorized goniometer head for small alignment motions. The absorption image is recorded by a single-crystal scintillator, an optical microscope and a cooled CCD array detector. Data reconstruction has provided three-dimensional geometry of the heterogeneous wood matrix in microtomographic images. Wood is a heterogeneous material composed of long lignocellulose vessels. Although wood is a strong natural product, fungi have evolved chemical systems that weaken the strength properties of wood by degrading structural vessels. Tomographic images with a resolution of three microns were obtained nonintrusively to characterize the compromised structural integrity of wood. Computational tools developed by Lindquist et al (1996) applied to characterize the microstructure of the tomographic volumes.

Characterization of Fractured Reservoirs Using a Combination of Downhole Pressure and Self-Potential Transient Data

Directory of Open Access Journals (Sweden)

Yuji Nishi

2012-01-01

Full Text Available In order to appraise the utility of self-potential (SP measurements to characterize fractured reservoirs, we carried out continuous SP monitoring using multi Ag-AgCl electrodes installed within two open holes at the Kamaishi Mine, Japan. The observed ratio of SP change to pressure change associated with fluid flow showed different behaviors between intact host rock and fractured rock regions. Characteristic behavior peculiar to fractured reservoirs, which is predicted from numerical simulations of electrokinetic phenomena in MINC (multiple interacting continua double-porosity media, was observed near the fractures. Semilog plots of the ratio of SP change to pressure change observed in one of the two wells show obvious transition from intermediate time increasing to late time stable trends, which indicate that the time required for pressure equilibration between the fracture and matrix regions is about 800 seconds. Fracture spacing was estimated to be a few meters assuming several micro-darcies (10-18 m2 of the matrix region permeability, which is consistent with geological and hydrological observations.

Chemical characterization and stable carbon isotopic composition of particulate Polycyclic Aromatic Hydrocarbons issued from combustion of 10 Mediterranean woods

Directory of Open Access Journals (Sweden)

A. Guillon

2013-03-01

Full Text Available The objectives of this study were to characterize polycyclic aromatic hydrocarbons from particulate matter emitted during wood combustion and to determine, for the first time, the isotopic signature of PAHs from nine wood species and Moroccan coal from the Mediterranean Basin. In order to differentiate sources of particulate-PAHs, molecular and isotopic measurements of PAHs were performed on the set of wood samples for a large panel of compounds. Molecular profiles and diagnostic ratios were measured by gas chromatography/mass spectrometry (GC/MS and molecular isotopic compositions (δ13C of particulate-PAHs were determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS. Wood species present similar molecular profiles with benz(aanthracene and chrysene as dominant PAHs, whereas levels of concentrations range from 1.8 to 11.4 mg g−1 OC (sum of PAHs. Diagnostic ratios are consistent with reference ratios from literature but are not sufficient to differentiate the species of woods. Concerning isotopic methodology, PAH molecular isotopic compositions are specific for each species and contrary to molecular fingerprints, significant variations of δ13C are observed for the panel of PAHs. This work allows differentiating wood combustion (with δ13CPAH = −28.7 to −26.6‰ from others origins of particulate matter (like vehicular exhaust using isotopic measurements but also confirms the necessity to investigate source characterisation at the emission in order to help and complete source assessment models. These first results on woodburnings will be useful for the isotopic approach to source tracking.

physico-chemical properties and energy potential of wood wastes

African Journals Online (AJOL)

user

were performed to assess the energy characteristics of the collected wood .... Methods. Wood processing activities were physically observed for. 6 days/wk at the sawmills for 15weeks. ..... [10] Oladeji, J T “Fuel characterization of briquettes.

Substitution potentials of recycled HDPE and wood particles from post-consumer packaging waste in Wood-Plastic Composites.

Science.gov (United States)

Sommerhuber, Philipp F; Welling, Johannes; Krause, Andreas

2015-12-01

The market share of Wood-Plastic Composites (WPC) is small but expected to grow sharply in Europe. This raises some concerns about suitable wood particles needed in the wood-based panels industry in Europe. Concerns are stimulated by the competition between the promotion of wooden products through the European Bioeconomy Strategy and wood as an energy carrier through the Renewable Energy Directive. Cascade use of resources and valorisation of waste are potential strategies to overcome resource scarcity. Under experimental design conditions, WPC made from post-consumer recycled wood and plastic (HDPE) were compared to WPC made from virgin resources. Wood content in the polymer matrix was raised in two steps from 0% to 30% and 60%. Mechanical and physical properties and colour differences were characterized. The feasibility of using cascaded resources for WPC is discussed. Results indicate the technical and economic feasibility of using recycled HDPE from packaging waste for WPC. Based on technical properties, 30% recycled wood content for WPC is feasible, but economic and political barriers of efficient cascading of biomass need to be overcome. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fracture Characterization in Enhanced Geothermal Systems by Wellbore and Reservoir Analysis

Energy Technology Data Exchange (ETDEWEB)

Horne, Roland N.; Li, Kewen; Alaskar, Mohammed; Ames, Morgan; Co, Carla; Juliusson, Egill; Magnusdottir, Lilja

2012-06-30

This report highlights the work that was done to characterize fractured geothermal reservoirs using production data. That includes methods that were developed to infer characteristic functions from production data and models that were designed to optimize reinjection scheduling into geothermal reservoirs, based on these characteristic functions. The characterization method provides a robust way of interpreting tracer and flow rate data from fractured reservoirs. The flow-rate data are used to infer the interwell connectivity, which describes how injected fluids are divided between producers in the reservoir. The tracer data are used to find the tracer kernel for each injector-producer connection. The tracer kernel describes the volume and dispersive properties of the interwell flow path. A combination of parametric and nonparametric regression methods were developed to estimate the tracer kernels for situations where data is collected at variable flow-rate or variable injected concentration conditions. The characteristic functions can be used to calibrate thermal transport models, which can in turn be used to predict the productivity of geothermal systems. This predictive model can be used to optimize injection scheduling in a geothermal reservoir, as is illustrated in this report.

Characterization of fracture networks for fluid flow analysis

International Nuclear Information System (INIS)

Long, J.C.S.; Billaux, D.; Hestir, K.; Majer, E.L.; Peterson, J.; Karasaki, K.; Nihei, K.; Gentier, S.; Cox, L.

1989-06-01

The analysis of fluid flow through fractured rocks is difficult because the only way to assign hydraulic parameters to fractures is to perform hydraulic tests. However, the interpretation of such tests, or ''inversion'' of the data, requires at least that we know the geometric pattern formed by the fractures. Combining a statistical approach with geophysical data may be extremely helpful in defining the fracture geometry. Cross-hole geophysics, either seismic or radar, can provide tomograms which are pixel maps of the velocity or attenuation anomalies in the rock. These anomalies are often due to fracture zones. Therefore, tomograms can be used to identify fracture zones and provide information about the structure within the fracture zones. This structural information can be used as the basis for simulating the degree of fracturing within the zones. Well tests can then be used to further refine the model. Because the fracture network is only partially connected, the resulting geometry of the flow paths may have fractal properties. We are studying the behavior of well tests under such geometry. Through understanding of this behavior, it may be possible to use inverse techniques to refine the a priori assignment of fractures and their conductances such that we obtain the best fit to a series of well test results simultaneously. The methodology described here is under development and currently being applied to several field sites. 4 refs., 14 figs

Heavy section steel technology program technical report No. 38. Fracture toughness characterization of HSST intermediate pressure vessel material

International Nuclear Information System (INIS)

Mager, T.R.; Yanichko, S.E.; Singer, L.R.

1974-12-01

The primary objective of the Heavy Section Steel Technology (HSST) Program is to develop pertinent fracture technology to demonstrate the structural reliability of present and contemplated water-cooled nuclear reactor pressure vessels. In order to demonstrate the ability to predict failure of large, heavy-walled pressure vessels under service type loading conditions, the fracture toughness properties of the vessel's materials must be characterized. The sampling procedure and test results are presented for vessel material supplied by the Oak Ridge National Laboratory that were used to characterize the fracture toughness of the HSST Intermediate Test Vessels. The metallurgical condition and heat treatment of the test material was representative of the vessel simulated service test condition. Test specimen locations and orientations were selected by the Oak Ridge National Laboratory and are representative of flaw orientations incorporated in the test vessels. The fracture toughness is documented for the materials from each of the eight HSST Intermediate Pressure Vessels tested to date. 7 references. (U.S.)

Characterization of hydraulic fracturing flowback water in Colorado: implications for water treatment.

Science.gov (United States)

Lester, Yaal; Ferrer, Imma; Thurman, E Michael; Sitterley, Kurban A; Korak, Julie A; Aiken, George; Linden, Karl G

2015-04-15

A suite of analytical tools was applied to thoroughly analyze the chemical composition of an oil/gas well flowback water from the Denver-Julesburg (DJ) basin in Colorado, and the water quality data was translated to propose effective treatment solutions tailored to specific reuse goals. Analysis included bulk quality parameters, trace organic and inorganic constituents, and organic matter characterization. The flowback sample contained salts (TDS=22,500 mg/L), metals (e.g., iron at 81.4 mg/L) and high concentration of dissolved organic matter (DOC=590 mgC/L). The organic matter comprised fracturing fluid additives such as surfactants (e.g., linear alkyl ethoxylates) and high levels of acetic acid (an additives' degradation product), indicating the anthropogenic impact on this wastewater. Based on the water quality results and preliminary treatability tests, the removal of suspended solids and iron by aeration/precipitation (and/or filtration) followed by disinfection was identified as appropriate for flowback recycling in future fracturing operations. In addition to these treatments, a biological treatment (to remove dissolved organic matter) followed by reverse osmosis desalination was determined to be necessary to attain water quality standards appropriate for other water reuse options (e.g., crop irrigation). The study provides a framework for evaluating site-specific hydraulic fracturing wastewaters, proposing a suite of analytical methods for characterization, and a process for guiding the choice of a tailored treatment approach. Copyright © 2015 Elsevier B.V. All rights reserved.

Wood handbook : wood as an engineering material

Science.gov (United States)

Robert J. Ross; Forest Products Laboratory. USDA Forest Service.

2010-01-01

Summarizes information on wood as an engineering material. Presents properties of wood and wood-based products of particular concern to the architect and engineer. Includes discussion of designing with wood and wood-based products along with some pertinent uses.

GC-MS Characterizations of Termiticidal Heartwood Extractives from Wood Species Utilized in Pakistan

Science.gov (United States)

Mark Mankowski; Blossie Boyd; Barbar Hassan; Grant T. Kirker

2016-01-01

Wood species that exhibit innate tolerance to wood destroying organisms such as termites are considered to be naturally durable. This durability can, in part, be due to the complex chemical compounds in the heartwood of naturally durable wood species. We examined the effects of varying concentrations of heartwood extractives on the subterranean termite, ...

3_D modeling using TLS and GPR techniques to characterize above and below-ground wood distribution in pyroclastic deposits along the Blanco River (Chilean Patagonia)

Science.gov (United States)

Valdebenito, Galo; Tonon, Alessia; Iroume, Andrés; Alvarado, David; Fuentes, Carlos; Picco, Lorenzo; Lenzi, Mario

2016-04-01

To date, the study of in-stream wood in rivers has been focused mainly on quantifying wood pieces deposited above the ground. However, in some particular river systems, the presence of buried dead wood can also represent an important component of wood recruitment and budgeting dynamics. This is the case of the Blanco River (Southern Chile) severely affected by the eruption of Chaitén Volcano occurred between 2008 and 2009. The high pyroclastic sediment deposition and transport affected the channel and the adjacent forest, burying wood logs and standing trees. The aim of this contribution is to assess the presence and distribution of wood in two study areas (483 m2 and 1989 m2, respectively) located along the lower streambank of the Blanco River, and covered by thick pyroclastic deposition up to 5 m. The study areas were surveyed using two different devices, a Terrestrial Laser Scanner (TLS) and a Ground Penetrating Radar (GPR). The first was used to scan the above surface achieving a high point cloud density (≈ 2000 points m-2) which allowed us to identify and measure the wood volume. The second, was used to characterize the internal morphology of the volcanic deposits and to detect the presence and spatial distribution of buried wood up to a depth of 4 m. Preliminary results have demonstrated differences in the numerousness and volume of above wood between the two study areas. In the first one, there were 43 wood elements, 33 standing trees and 10 logs, with a total volume of 2.96 m3 (109.47 m3 km-1), whereas the second one was characterized by the presence of just 7 standing trees and 11 wood pieces, for a total amount of 0.77 m3 (7.73 m3 km-1). The dimensions of the wood elements vary greatly according to the typology, standing trees show the higher median values in diameter and length (0.15 m and 2.91 m, respectively), whereas the wood logs were smaller (0.06 m and 1.12 m, respectively). The low dimensions of deposited wood can be probably connected to their

Advances in coalbed methane reservoirs using integrated reservoir characterization and hydraulic fracturing in Karaganda coal basin, Kazakhstan

Science.gov (United States)

Ivakhnenko, Aleksandr; Aimukhan, Adina; Kenshimova, Aida; Mullagaliyev, Fandus; Akbarov, Erlan; Mullagaliyeva, Lylia; Kabirova, Svetlana; Almukhametov, Azamat

2017-04-01

Coalbed methane from Karaganda coal basin is considered to be an unconventional source of energy for the Central and Eastern parts of Kazakhstan. These regions are situated far away from the main traditional sources of oil and gas related to Precaspian petroleum basin. Coalbed methane fields in Karaganda coal basin are characterized by geological and structural complexity. Majority of production zones were characterized by high methane content and extremely low coal permeability. The coal reservoirs also contained a considerable natural system of primary, secondary, and tertiary fractures that were usually capable to accommodate passing fluid during hydraulic fracturing process. However, after closing was often observed coal formation damage including the loss of fluids, migration of fines and higher pressures required to treat formation than were expected. Unusual or less expected reservoir characteristics and values of properties of the coal reservoir might be the cause of the unusual occurred patterns in obtained fracturing, such as lithological peculiarities, rock mechanical properties and previous natural fracture systems in the coals. Based on these properties we found that during the drilling and fracturing of the coal-induced fractures have great sensitivity to complex reservoir lithology and stress profiles, as well as changes of those stresses. In order to have a successful program of hydraulic fracturing and avoid unnecessary fracturing anomalies we applied integrated reservoir characterization to monitor key parameters. In addition to logging data, core sample analysis was applied for coalbed methane reservoirs to observe dependence tiny lithological variations through the magnetic susceptibility values and their relation to permeability together with expected principal stress. The values of magnetic susceptibility were measured by the core logging sensor, which is equipped with the probe that provides volume magnetic susceptibility parameters

Characterizing Fractures in Geysers Geothermal Field by Micro-seismic Data, Using Soft Computing, Fractals, and Shear Wave Anisotropy

Energy Technology Data Exchange (ETDEWEB)

Aminzadeh, Fred [Univ. of Southern California, Los Angeles, CA (United States); Sammis, Charles [Univ. of Southern California, Los Angeles, CA (United States); Sahimi, Mohammad [Univ. of Southern California, Los Angeles, CA (United States); Okaya, David [Univ. of Southern California, Los Angeles, CA (United States)

2015-04-30

The ultimate objective of the project was to develop new methodologies to characterize the northwestern part of The Geysers geothermal reservoir (Sonoma County, California). The goal is to gain a better knowledge of the reservoir porosity, permeability, fracture size, fracture spacing, reservoir discontinuities (leaky barriers) and impermeable boundaries.

Fracture network topology and characterization of structural permeability

Science.gov (United States)

Hansberry, Rowan; King, Rosalind; Holford, Simon

2017-04-01

There are two fundamental requirements for successful geothermal development: elevated temperatures at accessible depths, and a reservoir from which fluids can be extracted. The Australian geothermal sector has successfully targeted shallow heat, however, due in part to the inherent complexity of targeting permeability, obtaining adequate flow rates for commercial production has been problematic. Deep sedimentary aquifers are unlikely to be viable geothermal resources due to the effects of diagenetic mineral growth on rock permeability. Therefore, it is likely structural permeability targets, exploiting natural or induced fracture networks will provide the primary means for fluid flow in geothermal, as well as unconventional gas, reservoirs. Recent research has focused on the pattern and generation of crustal stresses across Australia, while less is known about the resultant networks of faults, joints, and veins that can constitute interconnected sub-surface permeability pathways. The ability of a fracture to transmit fluid is controlled by the orientation and magnitude of the in-situ stress field that acts on the fracture walls, rock strength, and pore pressure, as well as fracture properties such as aperture, orientation, and roughness. Understanding the distribution, orientation and character of fractures is key to predicting structural permeability. This project focuses on extensive mapping of fractures over various scales in four key Australian basins (Cooper, Otway, Surat and Perth) with the potential to host geothermal resources. Seismic attribute analysis is used in concert with image logs from petroleum wells, and field mapping to identify fracture networks that are usually not resolved in traditional seismic interpretation. We use fracture network topology to provide scale-invariant characterisation of fracture networks from multiple data sources to assess similarity between data sources, and fracture network connectivity. These results are compared with

Heat Resistance of Glued Finger Joints in Spruce Wood Constructions

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Martin Sviták

2014-10-01

Full Text Available The heat resistance of glued spruce wood was evaluated for different joint types and adhesives. Bending strength, modulus of elasticity, and also fracture evaluation were investigated on glued spruce samples made by the finger-jointed principle. Finger-jointed samples were glued with polyurethane (PUR and melamine-urea-formaldehyde (MUF adhesives. Heat loading was realized at temperatures 60, 80, and 110 °C and compared with wood with 20 °C. A static bending test with four-point flexural test was used. Elevated temperature and adhesive type had an important influence on the bending strength. On the other hand, adhesive type had a significant influence on the modulus of elasticity, but elevated temperature had no substantial influence.

Multipass comminution process to produce precision wood particles of uniform size and shape with disrupted grain structure from wood chips

Science.gov (United States)

Dooley, James H; Lanning, David N

2014-05-27

A process of comminution of wood chips (C) having a grain direction to produce a mixture of wood particles (P), wherein the wood chips are characterized by an average length dimension (L.sub.C) as measured substantially parallel to the grain, an average width dimension (W.sub.C) as measured normal to L.sub.C and aligned cross grain, and an average height dimension (H.sub.C) as measured normal to W.sub.C and L.sub.C, and wherein the comminution process comprises the step of feeding the wood chips in a direction of travel substantially randomly to the grain direction one or more times through a counter rotating pair of intermeshing arrays of cutting discs (D) arrayed axially perpendicular to the direction of wood chip travel.

HYGROSCOPICITY OF WOOD PLASTIC COMPOSITES MADE WITH PADOU FLOUR AND POLYPROPYLENE PELLETS

OpenAIRE

Moise Emmanuel NZUDJOM SOUOP; Joseph Albert MUKAM FOTSING

2012-01-01

The manufacture of objects in wood-plastic composites which is a material already available in many developed countries seems almost unknown in Cameroon since the production factory of objects in wood-plastic composites does not exist up till here. Interested in the study of properties of wood-plastic composites throughconnection of simple plastic and wood, we have oriented our paper in the elaboration, realization and physical characterization of wood-plastic composites with Padou and polypr...

Wood products in the waste stream: Characterization and combustion emissions. Volume 1. Final report

International Nuclear Information System (INIS)

1992-11-01

Waste wood is wood separated from the solid-waste stream and processed into a uniform-sized product that is reused for other purposes such as fuel. As an alternative to the combustion of fossil fuels, it has raised concerns that if it is 'contaminated' with paints, resins, preservatives, etc., unacceptable environmental impacts may be generated during combustion. Given the difficulty of separating contaminated materials from waste wood and the large energy potential existing in the resource, it is important to identify possible problems associated with contaminated waste wood combustion. The study describes research about technical, public policy, and regulatory issues that affect the processing and combustion of waste wood for fuel. The project's purpose was to provide environmental regulators, project developers, and others with data to make informed decisions on the use of waste wood materials as a combustion resource. Potential environmental problems and solutions were identified. A specific project result was the identification of combustion system operation parameters and air pollution control technologies that can minimize emissions of identified air and solid waste contaminants from combustion of wood waste

ANATOMICAL CHARACTERIZATION OF “CERRADO” VEGETATION WOOD FOR ENERGY PROUCTION

Directory of Open Access Journals (Sweden)

José Elias de Paula

2005-03-01

Full Text Available The wood anatomy of 7 from “cerrado”(chapada natives specie, Santa Quitéria(Maranhão was studied. Mainlyrelated to their qualification for energy production (charcoal and fire wood. The fraction of total area in a transverse section,fiber vessel, parenchyma cells, and total biomass per cubic meter of dry wood and also the basic density (specific weight ofwood were studied. For energy production, wall fraction in relation to the occupied area of the cell (%, percent of fibers,vessel, and both axial and ray parenchyma, as well as wall density were considered. The study was based in 3 areas in a crosssectionof the trunk, from the center towards the sapwood, called areas 1, 2 and 3. Based on anatomy and density mentioned,Lindackeria paraensis (farinha-seca, Parkia platycephala (faveira, Platonia insignis (bacuri, Salvertia convallariodora(folha-grande, Swartzia flaemingii(jacarandá, Vatarea macrocarpa (amargoso and Zeyhera tuberculata(pau-d”arcocabeludocan be classified as energy production tree species.

Integrated Modeling and Experiments to Characterize Coupled Thermo-hydro-geomechanical-chemical processes in Hydraulic Fracturing

Science.gov (United States)

Viswanathan, H. S.; Carey, J. W.; Karra, S.; Porter, M. L.; Rougier, E.; Kang, Q.; Makedonska, N.; Hyman, J.; Jimenez Martinez, J.; Frash, L.; Chen, L.

2015-12-01

Hydraulic fracturing phenomena involve fluid-solid interactions embedded within coupled thermo-hydro-mechanical-chemical (THMC) processes over scales from microns to tens of meters. Feedbacks between processes result in complex dynamics that must be unraveled if one is to predict and, in the case of unconventional resources, facilitate fracture propagation, fluid flow, and interfacial transport processes. The proposed work is part of a broader class of complex systems involving coupled fluid flow and fractures that are critical to subsurface energy issues, such as shale oil, geothermal, carbon sequestration, and nuclear waste disposal. We use unique LANL microfluidic and triaxial core flood experiments integrated with state-of-the-art numerical simulation to reveal the fundamental dynamics of fracture-fluid interactions to characterize the key coupled processes that impact hydrocarbon production. We are also comparing CO2-based fracturing and aqueous fluids to enhance production, greatly reduce waste water, while simultaneously sequestering CO2. We will show pore, core and reservoir scale simulations/experiments that investigate the contolling mechanisms that control hydrocarbon production.

Understanding the Use-wears on Non-retouched Shells Mytilus galloprovincialis. and Ruditapes decussatus by Performing Wood Working Experiment: An Experimental Approach

International Nuclear Information System (INIS)

Tumung, Laxmi; Bazgir, Behrouz; Ahmadi, Kamran; Shadmehr, Abdolkarim

2012-01-01

This paper is an experimental attempt to understand the use-wear comes on non-retouched shells Ruditapes decussatus and Mytilus galloprovincialis. These species have been selected due to their variation in shape, size and edge type. In wood working experiment Celtus australis wood is used to perform the activities like scrapping and cutting wood. The ESEM results show the usewears in the form of linear marks, edge rounding, edge facture, polish and micro-pitting. Experiments also showed some macro-fractures.

Wood : adhesives

Science.gov (United States)

A.H. Conner

2001-01-01

This chapter on wood adhesives includes: 1) Classification of wood adhesives 2) Thermosetting wood adhesives 3) Thermoplastic adhesives, 4) Wood adhesives based on natural sources 5) Nonconventional bonding of wood 6) Wood bonding.

Wood anatomy of the neotropical Sapotaceae. VI, Chloroluma

Science.gov (United States)

B. F. Kukachka

1978-01-01

The old genus Chloroluma has been reinstated to generic status after having been in synonomy under Chrysophyllum for many years. The description is based on the type species C. gonocarpa which is characterized by: Its clear yellow wood; pores in radial-echelon arrangement; rhombic, two-sized, and microcrystals frequent in the axial parenchyma and wood rays; colored...

Application of ATR-FTIR Spectroscopy to Compare the Cell Materials of Wood Decay Fungi with Wood Mould Fungi

Directory of Open Access Journals (Sweden)

Barun Shankar Gupta

2015-01-01

Full Text Available Wood fungi create vast damage among standing trees and all types of wood materials. The objectives of this study are to (a characterize the cell materials of two major wood decay fungi (Basidiomycota, namely, Trametes versicolor and Postia placenta, and (b compare the cell materials of decay fungi with four wood mould fungi (Ascomycota, namely, Aureobasidium pullulans, Alternaria alternata, Cladosporium cladosporioides, and Ulocladium atrum. Fourier transform infrared (FTIR spectroscopy is used to characterize the microbial cellular materials. The results showed that the IR bands for the fatty acid at ∼2900 cm−1 were different for the two-decay-fungi genre. Postia placenta shows more absorbance peaks at the fatty acid region. Band ratio indices for amide I and amide II from protein amino acids were higher for the mould fungi (Ascomycota than the decay fungi (Basidiomycota. Similarly, the band ratio index calculated for the protein end methyl group was found to be higher for the mould fungi than the decay fungi. Mould fungi along with the decay fungi demonstrated a positive correlation (R2=0.75 between amide I and amide II indices. The three-component multivariate, principal component analysis showed a strong correlation of amide and protein band indices.

Fluid-driven fracture propagation in heterogeneous media: Probability distributions of fracture trajectories.

Science.gov (United States)

Santillán, David; Mosquera, Juan-Carlos; Cueto-Felgueroso, Luis

2017-11-01

Hydraulic fracture trajectories in rocks and other materials are highly affected by spatial heterogeneity in their mechanical properties. Understanding the complexity and structure of fluid-driven fractures and their deviation from the predictions of homogenized theories is a practical problem in engineering and geoscience. We conduct a Monte Carlo simulation study to characterize the influence of heterogeneous mechanical properties on the trajectories of hydraulic fractures propagating in elastic media. We generate a large number of random fields of mechanical properties and simulate pressure-driven fracture propagation using a phase-field model. We model the mechanical response of the material as that of an elastic isotropic material with heterogeneous Young modulus and Griffith energy release rate, assuming that fractures propagate in the toughness-dominated regime. Our study shows that the variance and the spatial covariance of the mechanical properties are controlling factors in the tortuousness of the fracture paths. We characterize the deviation of fracture paths from the homogenous case statistically, and conclude that the maximum deviation grows linearly with the distance from the injection point. Additionally, fracture path deviations seem to be normally distributed, suggesting that fracture propagation in the toughness-dominated regime may be described as a random walk.

Comminution process to produce precision wood particles of uniform size and shape with disrupted grain structure from wood chips

Science.gov (United States)

Dooley, James H; Lanning, David N

2013-08-13

A process of comminution of wood chips (C) having a grain direction to produce a mixture of wood particles (P), wherein the wood chips are characterized by an average length dimension (L.sub.C) as measured substantially parallel to the grain, an average width dimension (W.sub.C) as measured normal to L.sub.C and aligned cross grain, and an average height dimension (H.sub.C) as measured normal to W.sub.C and L.sub.C, and wherein the comminution process comprises the step of feeding the wood chips in a direction of travel substantially randomly to the grain direction through a counter rotating pair of intermeshing arrays of cutting discs (D) arrayed axially perpendicular to the direction of wood chip travel, wherein the cutting discs have a uniform thickness (T.sub.D), and wherein at least one of L.sub.C, W.sub.C, and H.sub.C is greater than T.sub.D.

Functional lignocellulosic materials prepared by ATRP from a wood scaffold

Science.gov (United States)

Cabane, Etienne; Keplinger, Tobias; Künniger, Tina; Merk, Vivian; Burgert, Ingo

2016-01-01

Wood, a natural and abundant source of organic polymers, has been used as a scaffold to develop novel wood-polymer hybrid materials. Through a two-step surface-initiated Atom Transfer Radical Polymerization (ATRP), the porous wood structure can be effectively modified with polymer chains of various nature. In the present study, polystyrene and poly(N-isopropylacrylamide) were used. As shown with various characterization techniques including confocal Raman microscopy, FTIR, and SEM/EDX, the native wood ultrastructure and features are retained and the polymer chains can be introduced deep within the wood, i.e. inside the wood cell walls. The physical properties of the new materials have been studied, and results indicate that the insertion of polymer chains inside the wood cell wall alters the intrinsic properties of wood to yield a hybrid composite material with new functionalities. This approach to the functionalization of wood could lead to the fabrication of a new class of interesting functional materials and promote innovative utilizations of the renewable resource wood. PMID:27506369

Online molecular characterization of fine particulate matter in Port Angeles, WA: Evidence for a major impact from residential wood smoke

Science.gov (United States)

Gaston, Cassandra J.; Lopez-Hilfiker, Felipe D.; Whybrew, Lauren E.; Hadley, Odelle; McNair, Fran; Gao, Honglian; Jaffe, Daniel A.; Thornton, Joel A.

2016-08-01

We present on-line molecular composition measurements of wintertime particulate matter (PM) during 2014 using an iodide-adduct high-resolution, time-of-flight chemical ionization mass spectrometer (HR-TOF-CIMS) coupled to a Filter Inlet for Gases and AEROsols (FIGAERO). These measurements were part of an intensive effort to characterize PM in the region with a focus on ultrafine particle sources. The technique was used to detect and quantify different classes of wood burning tracers, including levoglucosan, methoxyphenols, and nitrocatechols, among other compounds in near real-time. During the campaign, particulate mass concentrations of compounds with the same molecular composition as levoglucosan ranged from 0.002 to 19 μg/m3 with a median mass concentration of 0.9 μg/m3. Wood burning markers, in general, showed a strong diurnal pattern peaking at night and in the early morning. This diurnal profile combined with cold, stagnant conditions, wind directions from predominantly residential areas, and observations of lower combustion efficiency at night support residential wood burning as a dominant source of wintertime PM in Port Angeles. This finding has implications for improving wintertime air quality in the region by encouraging the use of high efficiency wood-burning stoves or other cleaner home heating options throughout the relevant domain.

Modelling for the Stripa site characterization and validation drift inflow: prediction of flow through fractured rock

International Nuclear Information System (INIS)

Herbert, A.; Gale, J.; MacLeod, R.; Lanyon, G.

1991-12-01

We present our approach to predicting flow through a fractured rock site; the site characterization and validation region in the Stripa mine. Our approach is based on discrete fracture network modelling using the NAPSAC computer code. We describe the conceptual models and assumptions that we have used to interpret the geometry and flow properties of the fracture networks, from measurements at the site. These are used to investigate large scale properties of the network and we show that for flows on scales larger than about 10 m, porous medium approximation should be used. The porous medium groundwater flow code CFEST is used to predict the large scale flows through the mine and the SCV region. This, in turn, is used to provide boundary conditions for more detailed models, which predict the details of flow, using a discrete fracture network model, on scales of less than 10 m. We conclude that a fracture network approach is feasible and that it provides a better understanding of details of flow than conventional porous medium approaches and a quantification of the uncertainty associated with predictive flow modelling characterised from field measurement in fractured rock. (au)

Why ductile fracture mechanics

International Nuclear Information System (INIS)

Ritchie, R.O.

1983-01-01

Until recently, the engineering application of fracture mechanics has been specific to a description of macroscopic fracture behavior in components and structural parts which remain nominally elastic under loading. While this approach, termed linear elastic fracture mechanics, has been found to be invaluable for the continuum analysis of crack growth in brittle and high strength materials, it is clearly inappropriate for characterizing failure in lower strength ductile alloys where extensive inelastic deformation precedes and accompanies crack initiation and subsequent propagation. Accordingly, much effort has been devoted in recent years toward the development of nonlinear or ductile fracture mechanics methodology to characterize fracture behavior under elastic/plastic conditions; an effort which has been principally motivated by problems in nuclear industry. In this paper, the concepts of ductile (elastic/plastic) fracture mechanics are introduced and applied to the problem of both stationary and nonstationary cracks. Specifically, the limitations inherent in this approach are defined, together with a description of the microstructural considerations and applications relevant to the failure of ductile materials by fracture, fatigue, and creep

An integrated geophysical and hydraulic investigation to characterize a fractured-rock aquifer, Norwalk, Connecticut

Science.gov (United States)

Lane, J.W.; Williams, J.H.; Johnson, C.D.; Savino, D.M.; Haeni, F.P.

2002-01-01

The U.S. Geological Survey conducted an integrated geophysical and hydraulic investigation at the Norden Systems, Inc. site in Norwalk, Connecticut, where chlorinated solvents have contaminated a fractured-rock aquifer. Borehole, borehole-to-borehole, surface-geophysical, and hydraulic methods were used to characterize the site bedrock lithology and structure, fractures, and transmissive zone hydraulic properties. The geophysical and hydraulic methods included conventional logs, borehole imagery, borehole radar, flowmeter under ambient and stressed hydraulic conditions, and azimuthal square-array direct-current resistivity soundings. Integrated interpretation of geophysical logs at borehole and borehole-to-borehole scales indicates that the bedrock foliation strikes northwest and dips northeast, and strikes north-northeast to northeast and dips both southeast and northwest. Although steeply dipping fractures that cross-cut foliation are observed, most fractures are parallel or sub-parallel to foliation. Steeply dipping reflectors observed in the radar reflection data from three boreholes near the main building delineate a north-northeast trending feature interpreted as a fracture zone. Results of radar tomography conducted close to a suspected contaminant source area indicate that a zone of low electromagnetic (EM) velocity and high EM attenuation is present above 50 ft in depth - the region containing the highest density of fractures. Flowmeter logging was used to estimate hydraulic properties in the boreholes. Thirty-three transmissive fracture zones were identified in 11 of the boreholes. The vertical separation between transmissive zones typically is 10 to 20 ft. Open-hole and discrete-zone transmissivity was estimated from heat-pulse flowmeter data acquired under ambient and stressed conditions. The open-hole transmissivity ranges from 2 to 86 ft2/d. The estimated transmissivity of individual transmissive zones ranges from 0.4 to 68 ft2/d. Drawdown monitoring

Characterizing fractured plutonic rocks of the Canadian shield for deep geological disposal of Canada's radioactive wastes

International Nuclear Information System (INIS)

Lodha, G.S.; Davison, C.C.; Gascoyne, M.

1998-01-01

Since 1978 AECL has been investigating plutonic rocks of the Canadian Shield as a potential medium for the disposal of Canada's nuclear fuel waste. During the last two years this study has been continued as part of Ontario Hydro's used fuel disposal program. Methods have been developed for characterizing the geotechnical conditions at the regional scale of the Canadian Shield as well as for characterizing conditions at the site scale and the very near-field scale needed for locating and designing disposal vault rooms and waste emplacement areas. The Whiteshell Research Area (WRA) and the Underground Research Laboratory (URL) in southeastern Manitoba have been extensively used to develop and demonstrate the different scales of characterization methods. At the regional scale, airborne magnetic and electromagnetic surveys combined with LANDSAT 5 and surface gravity survey data have been helpful in identifying boundaries of the plutonic rocks , overburden thicknesses, major lineaments that might be geological structures, lithological contacts and depths of the batholiths. Surface geological mapping of exposed rock outcrops, combined with surface VLF/EM, radar and seismic reflection surveys were useful in identifying the orientation and depth continuity of low-dipping fracture zones beneath rock outcrops to a depth of 500 to 1000 m. The surface time-domain EM method has provided encouraging results for identifying the depth of highly saline pore waters. The regional site scale investigations at the WRA included the drilling of twenty deep boreholes (> 500 m) at seven separate study areas. Geological core logging combined with borehole geophysical logging, TV/ATV logging, flowmeter logging and full waveform sonic logging in these boreholes helped to confirm the location of hydro geologically important fractures, orient cores and infer the relative permeability of some fracture zones. Single-hole radar and crosshole seismic tomography surveys were useful to establish the

Characterizing and modelling the radionuclide transport properties of fracture zones in plutonic rocks of the Canadian Shield

International Nuclear Information System (INIS)

Davison, C.C.; Kozak, E.T.; Frost, L.H.; Everitt, R.A.; Brown, A.; Gascoyne, M.; Scheier, N.W.

1999-01-01

Plutonic rocks of the Canadian Shield were investigated as a potential host medium for nuclear fuel waste disposal of used CANDU nuclear fuel. Field investigations at several geologic research areas on the Shield have shown that major fracture zones are the dominant pathways for the large scale movement of groundwater and solutes through plutonic rock bodies. Because of this, a significant amount of the geoscience work has focused on methods to identify, characterize and model the radionuclide transport properties of major fracture zones in the fractured plutonic rocks of the Shield. In order to quantify the transport properties of such fracture zones a series of, groundwater tracer tests were performed over a period of several years in several major, low dipping fracture zones. Sixteen tracer tests were performed using dipole recirculation methods to evaluate transport over distance scales ranging from 17 m to 700 m. It was concluded that only tracer tests can provide useful estimates of the effective porosity and dispersivity characteristics of these large fracture zones in plutonic rocks of the Canadian Shield. (author)

Image analysis of multiple moving wood pieces in real time

Science.gov (United States)

Wang, Weixing

2006-02-01

This paper presents algorithms for image processing and image analysis of wood piece materials. The algorithms were designed for auto-detection of wood piece materials on a moving conveyor belt or a truck. When wood objects on moving, the hard task is to trace the contours of the objects in n optimal way. To make the algorithms work efficiently in the plant, a flexible online system was designed and developed, which mainly consists of image acquisition, image processing, object delineation and analysis. A number of newly-developed algorithms can delineate wood objects with high accuracy and high speed, and in the wood piece analysis part, each wood piece can be characterized by a number of visual parameters which can also be used for constructing experimental models directly in the system.

CHARACTERIZATION OF IN-SITU STRESS AND PERMEABILITY IN FRACTURED RESERVOIRS

Energy Technology Data Exchange (ETDEWEB)

Daniel R. Burns; M. Nafi Toksoz

2004-07-19

Expanded details and additional results are presented on two methods for estimating fracture orientation and density in subsurface reservoirs from scattered seismic wavefield signals. In the first, fracture density is estimated from the wavenumber spectra of the integrated amplitudes of the scattered waves as a function of offset in pre-stack data. Spectral peaks correctly identified the 50m, 35m, and 25m fracture spacings from numerical model data using a 40Hz source wavelet. The second method, referred to as the Transfer Function-Scattering Index Method, is based upon observations from 3D finite difference modeling that regularly spaced, discrete vertical fractures impart a ringing coda-type signature to any seismic energy that is transmitted through or reflected off of them. This coda energy is greatest when the acquisition direction is parallel to the fractures, the seismic wavelengths are tuned to the fracture spacing, and when the fractures have low stiffness. The method uses surface seismic reflection traces to derive a transfer function, which quantifies the change in an apparent source wavelet propagating through a fractured interval. The transfer function for an interval with low scattering will be more spike-like and temporally compact. The transfer function for an interval with high scattering will ring and be less temporally compact. A Scattering Index is developed based on a time lag weighting of the transfer function. When a 3D survey is acquired with a full range of azimuths, the Scattering Index allows the identification of subsurface areas with high fracturing and the orientation (or strike) of those fractures. The method was calibrated with model data and then applied to field data from a fractured reservoir giving results that agree with known field measurements. As an aid to understanding the scattered wavefield seen in finite difference models, a series of simple point scatterers was used to create synthetic seismic shot records collected over

Flow characteristics through a single fracture of artificial fracture system

International Nuclear Information System (INIS)

Park, Byoung Yoon; Bae, Dae Seok; Kim, Chun Soo; Kim, Kyung Su; Koh, Young Kwon; Jeon, Seok Won

2001-04-01

Fracture flow in rock masses is one of the most important issues in petroleum engineering, geology, and hydrogeology. Especially, in case of the HLW disposal, groundwater flow in fractures is an important factor in the performance assessment of the repository because the radionuclides move along the flowing groundwater through fractures. Recently, the characterization of fractures and the modeling of fluid flow in fractures are studied by a great number of researchers. Among those studies, the hydraulic behavior in a single fracture is one of the basic issues for understanding of fracture flow in rockmass. In this study, a fluid flow test in the single fracture made of transparent epoxy replica was carried out to obtain the practical exponent values proposed from the Cubic law and to estimate the flow rates through a single fracture. Not only the relationship between flow rates and the geometry of fracture was studied, but also the various statistical parameters of fracture geometry were compared to the effective transmissivity data obtained from computer simulation.

Fabrication of superhydrophobic wood surfaces via a solution-immersion process

Science.gov (United States)

Liu, Changyu; Wang, Shuliang; Shi, Junyou; Wang, Chengyu

2011-11-01

Superhydrophobic wood surfaces were fabricated from potassium methyl siliconate (PMS) through a convenient solution-immersion method. The reaction involves a hydrogen bond assembly and a polycondensation process. The silanol was formed by reacting PMS aqueous solution with CO2, which was assembled on the wood surface via hydrogen bonds with the wood surface -OH groups. The polymethylsilsesquioxane coating was obtained through the polycondensation reaction of the hydroxyl between wood and silanol. The morphology of products were characterized using a scanning electron microscope (SEM), the surface chemical composition was determined using energy dispersive X-ray analysis (EDXA), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TGA) and contact angle measurement. Analytical results revealed that rough protuberances uniformly covered the wood surface, thus transforming the wood surface from hydrophilic to superhydrophobic. The water contact angle of the superhydrophobic wood surface was about 153° and a sliding angle was 4.6°.

Simultaneous bond degradation and bond formation during phenol-formaldehyde curing with wood

Science.gov (United States)

Daniel J. Yelle; John Ralph

2016-01-01

Bonding of wood using phenol–formaldehyde adhesive develops highly durable bonds. Phenol– formaldehyde is believed to form primary bonds with wood cell wall polymers (e.g., lignin). However, it is unclear how this adhesive interacts and bonds to lignin. Through wood solubilisation methodologies, earlywood and latewood bonded assemblies were characterized using two-...

Hydrogeloogic characterization of fractured rock formations: A guide for groundwater remediators

International Nuclear Information System (INIS)

Cohen, A.J.B.

1995-10-01

A field site was developed in the foothills of the Sierra Nevada, California to develop and test a multi-disciplinary approach to the characterization of ground water flow and transport in fractured rocks. Nine boreholes were drilled into the granitic bedrock, and a wide variety of new and traditional subsurface characterization tools were implemented. The hydrogeologic structure and properties of the field site were deduced by integrating results from the various geologic, geophysical, hydrologic, and other investigative methods. The findings of this work are synthesized into this report, which is structured in a guidebook format. The applications of the new and traditional technologies, suggestions on how best to use, integrate, and analyze field data, and comparisons of the shortcoming and benefits of the different methods are presented

Hydrogeloogic characterization of fractured rock formations: A guide for groundwater remediators

Energy Technology Data Exchange (ETDEWEB)

Cohen, A.J.B.

1995-10-01

A field site was developed in the foothills of the Sierra Nevada, California to develop and test a multi-disciplinary approach to the characterization of ground water flow and transport in fractured rocks. Nine boreholes were drilled into the granitic bedrock, and a wide variety of new and traditional subsurface characterization tools were implemented. The hydrogeologic structure and properties of the field site were deduced by integrating results from the various geologic, geophysical, hydrologic, and other investigative methods. The findings of this work are synthesized into this report, which is structured in a guidebook format. The applications of the new and traditional technologies, suggestions on how best to use, integrate, and analyze field data, and comparisons of the shortcoming and benefits of the different methods are presented.

Cord Wood Testing in a Non-Catalytic Wood Stove

Energy Technology Data Exchange (ETDEWEB)

Butcher, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trojanowski, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wei, G. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2014-06-30

EPA Method 28 and the current wood stove regulations have been in-place since 1988. Recently, EPA proposed an update to the existing NSPS for wood stove regulations which includes a plan to transition from the current crib wood fuel to cord wood fuel for certification testing. Cord wood is seen as generally more representative of field conditions while the crib wood is seen as more repeatable. In any change of certification test fuel, there are questions about the impact on measured results and the correlation between tests with the two different fuels. The purpose of the work reported here is to provide data on the performance of a noncatalytic stove with cord wood. The stove selected has previously been certified with crib wood which provides a basis for comparison with cord wood. Overall, particulate emissions were found to be considerably higher with cord wood.

Wood-thermoplastic composites manufactured using beetle-killed spruce from Alaska

Science.gov (United States)

V. Yadama; Eini Lowell; N. Petersen; D. Nicholls

2009-01-01

The primary objectives of the study were to characterize the critical properties of wood flour produced using highly deteriorated beetle-killed spruce for wood-plastic composite (WPC) production and evaluate important mechanical and physical properties of WPC extruded using an industry standard formulation. Chemical composition analysis indicated no significant...

Preparation and Characterization of Activated Carbon Fibers from Liquefied Wood by ZnCl2 Activation

Directory of Open Access Journals (Sweden)

Zhigao Liu

2016-02-01

Full Text Available In this study, activated carbon fibers (ACFs were prepared from liquefied wood by chemical activation with ZnCl2, with a particular focus on the effects of temperature and ZnCl2: liquefied wood-based fiber (LWF ratio on yield, porous texture, and surface chemistry. The characterization and properties of these ACFs were investigated by nitrogen adsorption/desorption, Fourier transform infrared (FTIR spectroscopy, and X-ray photoelectron spectroscopy (XPS. When using a 6:1 impregnation ratio, the specific surface area (SBET of the resultant ACFs was as high as 1423 m2/g. The effect of an increase in impregnation ratio on the porosity of ACFs was stronger than that of an increase in the activation temperature. However, the former had a weaker impact on the surface chemistry and structure. It was also found that the yields of ACFs obtained by ZnCl2 activation were higher than those obtained by physical activation. Besides, the prepared ACFs presented higher adsorption than other raw materials in the adsorption test, indicating that ACFs prepared from LWF by ZnCl2 activation could be used as an adsorbent for the adsorption of medium size organic compounds.

Importance of wood from planted forests for manufacturing industry

Directory of Open Access Journals (Sweden)

Victor Almeida De Araujo

2017-06-01

Full Text Available The manufactured wood products are essential to modern society, since they are made from renewable and recyclable raw material, characterizing a sustainable input. The objective of this study was to elucidate the importance of wood from planted forests in forest products manufacture of higher added value, addressing forest and wood contexts of topics related to education, resources, products, industry, government incentives, public policies and markets. Different from Europe, it was verified that Brazil does not support positively this important industrial sector, nevertheless it still presents growth potential due to range of wooden-based products. Thus, wood could reach a prominent position in Brazilian economy, if strategies and incentives were defined by rules and public policies..

Characterization of dielectric properties of nanocellulose from wood and algae for electrical insulator applications.

Science.gov (United States)

Le Bras, David; Strømme, Maria; Mihranyan, Albert

2015-05-07

Cellulose is one of the oldest electrically insulating materials used in oil-filled high-power transformers and cables. However, reports on the dielectric properties of nanocellulose for electrical insulator applications are scarce. The aim of this study was to characterize the dielectric properties of two nanocellulose types from wood, viz., nanofibrillated cellulose (NFC), and algae, viz., Cladophora cellulose, for electrical insulator applications. The cellulose materials were characterized with X-ray diffraction, nitrogen gas and moisture sorption isotherms, helium pycnometry, mechanical testing, and dielectric spectroscopy at various relative humidities. The algae nanocellulose sample was more crystalline and had a lower moisture sorption capacity at low and moderate relative humidities, compared to NFC. On the other hand, it was much more porous, which resulted in lower strength and higher dielectric loss than for NFC. It is concluded that the solid-state properties of nanocellulose may have a substantial impact on the dielectric properties of electrical insulator applications.

Roughness study on homogeneous layer panels manufactured from treated wood waste

Directory of Open Access Journals (Sweden)

Maria Fátima do Nascimento

2017-02-01

Full Text Available Natural resource exploration is growing, highlighting woods and joinery waste, wood industries and the like. This study presents homogeneous particleboard (PPH roughness characterization manufactured from treated wood waste. Normative document with values of Brazilian Technical Standard Association ABNT NBR 8404 (1984, was adopted as a reference. The results show that the manufactured PPH showed roughness class N 10, with roughness values (Ra of less than 12.5 microns.

Techniques for Source Zone and Plume Characterization of Tetrachloroethene in Fractured Limestone Aquifers

DEFF Research Database (Denmark)

Fjordbøge, Annika Sidelmann; Mosthaf, Klaus; Janniche, Gry S.

Characterization of chlorinated solvents in fractured limestone aquifers is essential for proper development of site specific conceptual models and subsequent risk assessment and remediation. High resolution characterization is challenged by the difficulties involved in collection of intact core...... an improved conceptual understanding of contaminant transport. At both sites limestone cores were collected with significant core losses. The discrete quantification of chlorinated solvents in the retrieved limestone cores was compared to different FLUTe technologies at the DNAPL site and passive and active...... distribution compared to the data obtained by quantification of chlorinated solvents in the limestone cores....

Assessment of the wood waste resource and its position in the wood / wood-energy sector - Synthesis

International Nuclear Information System (INIS)

Guinard, Ludovic; Deroubaix, Gerard; Roux, Marie-Lise; Levet, Anne-Laure; Quint, Vincent

2015-04-01

The first objective of this study is to obtain a better knowledge of the 'wood wastes' issue, to propose a photography of the wood waste sector (productions, trades, consumptions), and then to elaborate different prospective scenarios on the use of wood waste volumes while taking into account possible evolutions on the medium or short term of the regulation and market of the wood/wood energy sector. The considered wastes come from industrial production, from the use of wood-based products, and from the end of life of products potentially containing wood. The authors present bibliographical sources and the adopted methodology, briefly describe the 'wood waste' system with its actors, and then report their assessment of wood wastes. They propose a global assessment as well as detailed assessments with respect to waste origins: wood trade and distribution, industries, craft, households and communities, building sector, public and private tertiary sector, packaging. They also address the collection and management of wood wastes by public services, and present the different types of valorisation (panel fabrication, energy, and others). They discuss exports, and then present different scenarios: a trend-based scenario, and two prospective scenarios with a priority to energetic valorisation or to material valorisation of wood wastes. These scenarios are compared

Mixed-Mode Crack Growth in Wood

Directory of Open Access Journals (Sweden)

Octavian POP

2012-09-01

Full Text Available In timber elements the mixed mode dependsessentially of wood anatomy and load configuration.In these conditions, in order to evaluate the materialbehavior and the fracture process, it’s necessary toseparate the part of each mode. The mixed modeseparation allows evaluating the amplitude offracture mode. In the present paper, using a mixedmodecrack growth specimen made in Douglas fir,the mixed mode crack growth process is studythanks to marks tracking method. Using the markstracking method the characteristic displacementsassociated to opening and shear mode aremeasured. From the experimental measurements,the energy release rate associated to opening andshear modes is calculated into to account the crackadvancement during the test.

Quantifying Fracture Heterogeneity in Different Domains of Folded Carbonate Rocks to Improve Fractured Reservoir Analog Fluid Flow Models

NARCIS (Netherlands)

Bisdom, K.; Bertotti, G.; Gauthier, B.D.M.; Hardebol, N.J.

2013-01-01

Fluid flow in carbonate reservoirs is largely controlled by multiscale fracture networks. Significant variations of fracture network porosity and permeability are caused by the 3D heterogeneity of the fracture network characteristics, such as intensity, orientation and size. Characterizing fracture

THERMAL DEGRADATION AND MORPHOLOGICAL ASPECTS OF FOUR WOOD SPECIES USED IN LUMBER INDUSTRY

Directory of Open Access Journals (Sweden)

Matheus Poletto

Full Text Available ABSTRACT The aim of this work was characterize four wood waste samples from lumber industry in order to obtain previous information about structure and properties of wood before use it as a biofuel or as reinforcement in composite formulations. The influence of wood components on the thermal degradation stability of different wood species has been investigated using thermogravimetry, differential scanning calorimetry and scanning electron microscopy. Four wood species, Eucalyptus grandis (EUG, Pinus elliottii (PIE, Dipteryx odorata (DIP and Mezilaurus itauba (ITA, were used in this study. The results showed that higher extractives contents may form a thin film on the wood fiber surface which can accelerate the degradation process and reduce the wood thermal stability

Optimization of wood plastic composite decks

Science.gov (United States)

Ravivarman, S.; Venkatesh, G. S.; Karmarkar, A.; Shivkumar N., D.; Abhilash R., M.

2018-04-01

Wood Plastic Composite (WPC) is a new class of natural fibre based composite material that contains plastic matrix reinforced with wood fibres or wood flour. In the present work, Wood Plastic Composite was prepared with 70-wt% of wood flour reinforced in polypropylene matrix. Mechanical characterization of the composite was done by carrying out laboratory tests such as tensile test and flexural test as per the American Society for Testing and Materials (ASTM) standards. Computer Aided Design (CAD) model of the laboratory test specimen (tensile test) was created and explicit finite element analysis was carried out on the finite element model in non-linear Explicit FE code LS - DYNA. The piecewise linear plasticity (MAT 24) material model was identified as a suitable model in LS-DYNA material library, describing the material behavior of the developed composite. The composite structures for decking application in construction industry were then optimized for cross sectional area and distance between two successive supports (span length) by carrying out various numerical experiments in LS-DYNA. The optimized WPC deck (Elliptical channel-2 E10) has 45% reduced weight than the baseline model (solid cross-section) considered in this study with the load carrying capacity meeting acceptance criterion (allowable deflection & stress) for outdoor decking application.

PHYSICAL AND MECHANICAL PROPERTIES OF JUVENILE Schizolobium amazonicum WOOD

Directory of Open Access Journals (Sweden)

Graziela Baptista Vidaurre

2018-03-01

Full Text Available ABSTRACT Growth in world demand for wood implies a search for new fast growing species with silvicultural potential, and in this scenario for native species such as Paricá . Thus, the objective of this study was determining the physical and mechanical wood properties of the Schizolobium amazonicum species (known as Paricá in Brazil. Trees were collected from commercial plantations located in the north of Brazil with ages of 5, 7, 9 and 11 years. Four logs from trees of each age in the longitudinal direction of the trees were obtained, and later a diametrical plank of each log was taken to manufacture the specimens which were used to evaluate some physical and mechanical properties of the wood. The basic density of Paricá was reduced in the basetop direction and no difference between the radial positions was observed, while the average basic density of this wood was characterized as low. The region close to the bark showed less longitudinal contraction and also greater homogeneity of this property along the trunk, while for tangential contraction the smallest variation was found in the region near the pith. Paricá wood contraction was characterized as low. Age influenced most of the mechanical properties, where logs from the base had the highest values of mechanical strength.

Chapter 6: Wood energy and competing wood product markers

Science.gov (United States)

Kenneth E. Skog; Robert C. Abt; Karen Abt

2014-01-01

Understanding the effect of expanding wood energy markets is important to all wood-dependent industries and to policymakers debating the implementation of public programs to support the expansion of wood energy generation. A key factor in determining the feasibility of wood energy projects (e.g. wood boiler or pellet plant) is the long-term (i.e. 20-30year) supply...

Selective arteriography in femoral head fractures

Energy Technology Data Exchange (ETDEWEB)

Mannella, P; Galeotti, R; Borrelli, M; Benea, G; Massari, L; Chiarelli, G M

1986-01-01

The choice between conservative and radical operation in case of femoral neck fractures is very important because it is the determining factor for a successfull therapy. In case of epiphysial necrosis, an endoprosthesis as well as an osteosynthesis will be carried out. Selective arteriography of the medical circumflex artery represents the most reliable study to establish, immediately after the fractures, the possible presence of a post-traumatic ischemic necrosis. Angiography, as a reliable diagnostic tool, has to be carried out in the most selective way and needs the image subtraction technique. The authors report their preliminary results on the reliability of angiography in the femoral epiphyseal ischemic necrosis diagnosed by comparing the results of angiography with the wood light test carried out on the surgically removed femoral head. 18 refs.

Wood adhesives : vital for producing most wood products

Science.gov (United States)

Charles R. Frihart

2011-01-01

A main route for the efficient utilization of wood resources is to reduce wood to small pieces and then bond them together (Frihart and Hunt 2010). Although humankind has been bonding wood since early Egyptian civilizations, the quality and quantity of bonded wood products has increased dramatically over the past 100 years with the development of new adhesives and...

Mechanical properties of fracture zones

International Nuclear Information System (INIS)

Leijon, B.

1993-05-01

Available data on mechanical characteristics of fracture zones are compiled and discussed. The aim is to improve the basis for adequate representation of fracture zones in geomechanical models. The sources of data researched are primarily borehole investigations and case studies in rock engineering, involving observations of fracture zones subjected to artificial load change. Boreholes only yield local information about the components of fracture zones, i.e. intact rock, fractures and various low-strength materials. Difficulties are therefore encountered in evaluating morphological and mechanical properties of fracture zones from borehole data. Although often thought of as macroscopically planar features, available field data consistently show that fracture zones are characterized by geometrical irregularities such as thickness variations, surface undulation and jogs. These irregularities prevail on all scales. As a result, fracture zones are on all scales characterized by large, in-plane variation of strength- and deformational properties. This has important mechanical consequences in terms of non-uniform stress transfer and complex mechanisms of shear deformation. Field evidence for these findings, in particular results from the underground research laboratory in Canada and from studies of induced fault slip in deep mines, is summarized and discussed. 79 refs

Precision wood particle feedstocks with retained moisture contents of greater than 30% dry basis

Science.gov (United States)

Dooley, James H; Lanning, David N

2014-10-28

Wood particles having fibers aligned in a grain, wherein: the wood particles are characterized by a length dimension (L) aligned substantially parallel to the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L; the L.times.H dimensions define two side surfaces characterized by substantially intact longitudinally arrayed fibers; the W.times.H dimensions define two cross-grain end surfaces characterized individually as aligned either normal to the grain or oblique to the grain; the L.times.W dimensions define two substantially parallel top and bottom surfaces; and, a majority of the W.times.H surfaces in the mixture of wood particles have end checking.

Microclimate and habitat heterogeneity as the major drivers of beetle diversity in dead wood

Science.gov (United States)

Sebastian Seibold; Claus Bassler; Roland Brandl; Boris Buche; Alexander Szallies; Simon Thorn; Michael D. Ulyshen; Jorg Muller; Christopher Baraloto

2016-01-01

1. Resource availability and habitat heterogeneity are principle drivers of biodiversity, but their individual roles often remain unclear since both factors are usually correlated. The biodiversity of species dependent on dead wood could be driven by either resource availability represented by dead-wood amount or habitat heterogeneity characterized by dead-wood...

Ankle fractures have features of an osteoporotic fracture.

Science.gov (United States)

Lee, K M; Chung, C Y; Kwon, S S; Won, S H; Lee, S Y; Chung, M K; Park, M S

2013-11-01

We report the bone attenuation of ankle joint measured on computed tomography (CT) and the cause of injury in patients with ankle fractures. The results showed age- and gender-dependent low bone attenuation and low-energy trauma in elderly females, which suggest the osteoporotic features of ankle fractures. This study was performed to investigate the osteoporotic features of ankle fracture in terms of bone attenuation and cause of injury. One hundred ninety-four patients (mean age 51.0 years, standard deviation 15.8 years; 98 males and 96 females) with ankle fracture were included. All patients underwent CT examination, and causes of injury (high/low-energy trauma) were recorded. Mean bone attenuations of the talus, medial malleolus, lateral malleolus, and distal tibial metaphysis were measured on CT images. Patients were divided into younger age (fractures than the younger age group. With increasing age, bone attenuations tended to decrease and the difference of bone attenuation between the genders tended to increase in the talus, medial malleolus, lateral malleolus, and distal tibial metaphysis. Ankle fracture had features of osteoporotic fracture that is characterized by age- and gender-dependent low bone attenuation. Ankle fracture should not be excluded from the clinical and research interest as well as from the benefit of osteoporosis management.

Site characterization and validation - validation drift fracture data, stage 4

International Nuclear Information System (INIS)

Bursey, G.; Gale, J.; MacLeod, R.; Straahle, A.; Tiren, S.

1991-08-01

This report describes the mapping procedures and the data collected during fracture mapping in the validation drift. Fracture characteristics examined include orientation, trace length, termination mode, and fracture minerals. These data have been compared and analysed together with fracture data from the D-boreholes to determine the adequacy of the borehole mapping procedures and to assess the nature and degree of orientation bias in the borehole data. The analysis of the validation drift data also includes a series of corrections to account for orientation, truncation, and censoring biases. This analysis has identified at least 4 geologically significant fracture sets in the rock mass defined by the validation drift. An analysis of the fracture orientations in both the good rock and the H-zone has defined groups of 7 clusters and 4 clusters, respectively. Subsequent analysis of the fracture patterns in five consecutive sections along the validation drift further identified heterogeneity through the rock mass, with respect to fracture orientations. These results are in stark contrast to the results form the D-borehole analysis, where a strong orientation bias resulted in a consistent pattern of measured fracture orientations through the rock. In the validation drift, fractures in the good rock also display a greater mean variance in length than those in the H-zone. These results provide strong support for a distinction being made between fractures in the good rock and the H-zone, and possibly between different areas of the good rock itself, for discrete modelling purposes. (au) (20 refs.)

Wood frame systems for wood homes

Directory of Open Access Journals (Sweden)

Julio Cesar Molina

2010-12-01

Full Text Available The use of constructive systems that combine strength, speed, with competitive differential techniques and mainly, compromising with the environment, is becoming more popular in Brazil. The constructive system in wood frame for houses of up to five stories is very interesting, because it is a light system, structured in reforested treated wood which allows the combination of several materials, besides allowing speed in the construction and total control of the expenses already in the project phase for being industrialized. The structural behavior of the wood frame is superior to the structural masonry in strength, thermal and acoustic comfort. However, in Brazil, the wood frame is still little known and used, due to lack of technical knowledge about the system, prejudice associated the bad use of the wood as construction material, or still, in some cases, lack of normalization. The aim of this manuscript consists of presenting the main technical characteristics and advantages of the constructive system in wood frame homes, approaching the main stages of the constructive process through examples, showing the materials used in the construction, in addition the main international normative recommendations of the project. Thus, this manuscript also hopes to contribute to the popularization of the wood frame system in Brazil, since it is a competitive, fast and ecologically correct system. Moreover, nowadays, an enormous effort of the technical, commercial and industrial section has been accomplished for the development of this system in the country.

Physical and chemical characterization of waste wood derived biochars.

Science.gov (United States)

Yargicoglu, Erin N; Sadasivam, Bala Yamini; Reddy, Krishna R; Spokas, Kurt

2015-02-01

Biochar, a solid byproduct generated during waste biomass pyrolysis or gasification in the absence (or near-absence) of oxygen, has recently garnered interest for both agricultural and environmental management purposes owing to its unique physicochemical properties. Favorable properties of biochar include its high surface area and porosity, and ability to adsorb a variety of compounds, including nutrients, organic contaminants, and some gases. Physical and chemical properties of biochars are dictated by the feedstock and production processes (pyrolysis or gasification temperature, conversion technology and pre- and post-treatment processes, if any), which vary widely across commercially produced biochars. In this study, several commercially available biochars derived from waste wood are characterized for physical and chemical properties that can signify their relevant environmental applications. Parameters characterized include: physical properties (particle size distribution, specific gravity, density, porosity, surface area), hydraulic properties (hydraulic conductivity and water holding capacity), and chemical and electrochemical properties (organic matter and organic carbon contents, pH, oxidation-reduction potential and electrical conductivity, zeta potential, carbon, nitrogen and hydrogen (CHN) elemental composition, polycyclic aromatic hydrocarbons (PAHs), heavy metals, and leachable PAHs and heavy metals). A wide range of fixed carbon (0-47.8%), volatile matter (28-74.1%), and ash contents (1.5-65.7%) were observed among tested biochars. A high variability in surface area (0.1-155.1g/m(2)) and PAH and heavy metal contents of the solid phase among commercially available biochars was also observed (0.7-83 mg kg(-1)), underscoring the importance of pre-screening biochars prior to application. Production conditions appear to dictate PAH content--with the highest PAHs observed in biochar produced via fast pyrolysis and lowest among the gasification

Weathering properties of treated southern yellow pine wood examined by X-ray photoelectron spectroscopy, scanning electron microscopy and physical characterization

Energy Technology Data Exchange (ETDEWEB)

Salaita, Ghaleb N.; Ma, Frank M.S.; Parker, Trudy C. [Dow Chemical Company, Technical Center, 3200 Kanawha Turnpike, South Charleston, WV 25303 (United States); Hoflund, Gar B. [Department of Chemical Engineering, University of Florida, P.O. Box 116005, Gainesville, FL 32611 (United States)], E-mail: garho@hotmail.com

2008-04-30

In this study the weathering behavior of southern yellow pine (SYP) wood samples pretreated in different solutions has been examined using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and various types of physical characterization regarding material loss and discoloration. The treatment solutions include water as a control, a commercially available water repellent (WR) wood treating additive and polyethylene glycol (PEG) products including PEG PLUS{sup TM}, PEG 8000 solutions and Compound 20M in varying concentrations. All contained the wood preservative chromated copper arsenate (CCA). One sample was treated with a CCA solution only. The treatments were carried out at 20 deg. C and 150 psig for 1/2 h after exposure to vacuum (28 mmHg) for 15 min. Simulated weathering was achieved in an Atlas 65-W Weather-Ometer for 2000 h with both light and dark periods and rain. The temperature ranged from 23 deg. C during the dark cycle to 35 deg. C during the light cycle. With weathering the XPS O/C ratios increase due to oxidation of the surface. Exposure to UV light results in bond breakage and reaction with oxygen in the presence of air to form organic functional groups such as , , C=O and/or O-C-O. These oxidized products can protect the underlying wood from deterioration if they are insoluble in water and remain on the surface as a protective coating. If soluble, rain washes the compounds away and assists in the degradation. Correlated changes are observed in the XPS O/C ratios, the high-resolution XPS C 1s spectra, the SEM micrographs and physical measurements including thickness alteration, weight loss, and discoloration by yellowing or whitening of the weathered wood. The PEG treatments are effective in protecting wood with the 2% PEG PLUS treatment providing the best weathering behavior similar to that of the CCA treatment. The WR and water treatments yield the poorest weathering properties.

Weathering properties of treated southern yellow pine wood examined by X-ray photoelectron spectroscopy, scanning electron microscopy and physical characterization

International Nuclear Information System (INIS)

Salaita, Ghaleb N.; Ma, Frank M.S.; Parker, Trudy C.; Hoflund, Gar B.

2008-01-01

In this study the weathering behavior of southern yellow pine (SYP) wood samples pretreated in different solutions has been examined using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and various types of physical characterization regarding material loss and discoloration. The treatment solutions include water as a control, a commercially available water repellent (WR) wood treating additive and polyethylene glycol (PEG) products including PEG PLUS TM , PEG 8000 solutions and Compound 20M in varying concentrations. All contained the wood preservative chromated copper arsenate (CCA). One sample was treated with a CCA solution only. The treatments were carried out at 20 deg. C and 150 psig for 1/2 h after exposure to vacuum (28 mmHg) for 15 min. Simulated weathering was achieved in an Atlas 65-W Weather-Ometer for 2000 h with both light and dark periods and rain. The temperature ranged from 23 deg. C during the dark cycle to 35 deg. C during the light cycle. With weathering the XPS O/C ratios increase due to oxidation of the surface. Exposure to UV light results in bond breakage and reaction with oxygen in the presence of air to form organic functional groups such as , , C=O and/or O-C-O. These oxidized products can protect the underlying wood from deterioration if they are insoluble in water and remain on the surface as a protective coating. If soluble, rain washes the compounds away and assists in the degradation. Correlated changes are observed in the XPS O/C ratios, the high-resolution XPS C 1s spectra, the SEM micrographs and physical measurements including thickness alteration, weight loss, and discoloration by yellowing or whitening of the weathered wood. The PEG treatments are effective in protecting wood with the 2% PEG PLUS treatment providing the best weathering behavior similar to that of the CCA treatment. The WR and water treatments yield the poorest weathering properties

Subtrochanteric fractures in bisphosphonate-naive patients

DEFF Research Database (Denmark)

Adachi, Jonathan D; Lyles, Kenneth; Boonen, Steven

2011-01-01

Our purpose was to characterize the risks of osteoporosis-related subtrochanteric fractures in bisphosphonate-naive individuals. Baseline characteristics of patients enrolled in the HORIZON-Recurrent Fracture Trial with a study-qualifying hip fracture were examined, comparing those who sustained ...

Physical, mechanical, and biodegradable properties of meranti wood polymer composites

International Nuclear Information System (INIS)

Enamul Hoque, M.; Aminudin, M.A.M.; Jawaid, M.; Islam, M.S.; Saba, N.; Paridah, M.T.

2014-01-01

Highlights: • In-situ polymerization and solution casting method used to manufacture WPC. • In-situ WPC exhibited better properties compared to pure wood, 5% WPC and 20% WPC. • Lowest water absorption and least biodegradability shown by In-situ wood. - Abstract: In-situ polymerization and solution casting techniques are two effective methods to manufacture wood polymer composites (WPCs). In this study, wood polymer composites (WPCs) were manufactured from meranti sapwood by solution casting and in-situ polymerization process using methyl methacrylate (MMA) and epoxy matrix respectively. Physical, mechanical, and morphological characterizations of fabricated WPCs were then carried out to analyse their properties. Morphological properties of composites samples were analyzed through scanning electron microscopy (SEM). The result reveals that in-situ wood composite exhibited better properties compared to pure wood, 5% WPC and 20% WPC. Moreover, in-situ WPC had lowest water absorption and least biodegraded. Conversely, pure wood shown moderate mechanical strength, high biodegradation and water absorption rate. In term of biodegradation, earth-medium brought more severe effect than water in deteriorating the properties of the specimens

Wood

DEFF Research Database (Denmark)

Unterrainer, Walter

2014-01-01

come from? How is it harvested? How is it manufactured and treated ? How are the buildings detailed and protected against weather during construction to keep them dry and make them long-life ? In a period of climate change, forests are the last lungs of the planet to sequestrate CO2. Their global size......Wood – a sustainable building material ? For thousands of years and all over the planet, wood has been used as a building material and exciting architecture has been created in wood. The fantastic structural, physical and aesthetic properties of the material as well as the fact that wood...

A NOVEL FIRE RETARDANT AFFECTS FIRE PERFORMANCE AND MECHANICAL PROPERTIES OF WOOD FLOUR-HIGH DENSITY POLYETHYLENE COMPOSITES

Directory of Open Access Journals (Sweden)

Mingzhu Pan,

2012-02-01

Full Text Available Wood flour-high density polyethylene (HDPE composites were prepared to investigate the effects of ammonium polyphosphate based fire retardant content (2, 4, 6, 8, and 10-wt%, on the flammability, mechanical, and morphological properties of the wood flour-HDPE composites in this study. Cone calorimetry analysis showed that the addition of fire retardant could decrease the heat release rate (HRR and total smoke release of wood flour-HDPE composites, while it had no obviously effects on effective heat of combustion. Most of the decrease of the HRR occurred with the concentration of the fire retardant up to 4-wt%. With addition of fire retardant, the composites showed a decrease in tensile elongation at break and impact strength, and had no obvious effect on tensile and flexural strength. The scanning electron microscopy observation on the fracture surface of the composites indicated that fire retardant had a uniform dispersion in the wood flour-HDPE composites. However, interfacial bonding would be suggested to improve in wood flour-HDPE composites with ammonium polyphosphate based fire retardant.

MOLECULAR CHARACTERIZATION OF SMOKE FROM CAMPFIRE BURNING OF PINE WOOD (PINUS ELLIOTTII). (R823990)

Science.gov (United States)

AbstractAlthough campfires are typically enjoyable events, people are exposed to high concentrations of gaseous and particulate pollutants. The combustion conditions of wood burned in campfires are different from those of indoor wood burning in stoves or fireplaces. T...

Wood burning

Energy Technology Data Exchange (ETDEWEB)

Winkelmann, H

1955-01-01

Discussed are the use of wood as a fuel, the technique of wood combustion and the operation of wood-burning stoves for cooking and heating. In addition, there is a section which reviews the use of wood stoves in various countries and lists manufacturers of stoves, central heating furnaces and in some cases sawdust burners.

Advanced reservoir characterization and evaluation of CO2 gravity drainage in the naturally fractured Spraberry Trend Area. Annual report, September 1, 1996--August 31, 1997

Energy Technology Data Exchange (ETDEWEB)

McDonald, P.

1998-06-01

The objective of the Spraberry CO{sub 2} pilot project is to determine the technical and economic feasibility of continuous CO{sub 2} injection in the naturally fractured reservoirs of the Spraberry Trend. In order to describe, understand, and model CO{sub 2} flooding in the naturally fractured Spraberry reservoirs, characterization of the fracture system is a must. Additional reservoir characterization was based on horizontal coring in the second year of the project. In addition to characterization of natural fractures, horizontal coring has confirmed a previously developed rock model for describing the Spraberry Trend shaly sands. A better method for identifying Spraberry pay zones has been verified. The authors have completed the reservoir characterization, which includes matrix description and detection (from core-log integration) and fracture characterization. This information is found in Section 1. The authors have completed extensive imbibition experiments that strongly indicate that the weakly water-wet behavior of the reservoir rock may be responsible for poor waterflood response observed in many Spraberry fields. The authors have also made significant progress in analytical and numerical simulation of performance in Spraberry reservoirs as seen in Section 3. They have completed several suites of CO{sub 2} gravity drainage in Spraberry and Berea whole cores at reservoir conditions and reported in Section 4. The results of these experiments have been useful in developing a model for free-fall gravity drainage and have validated the premise that CO{sub 2} will recover oil from tight, unconfined Spraberry matrix.

Fractures in infants and toddlers with rickets

Energy Technology Data Exchange (ETDEWEB)

Chapman, Teresa; Done, Stephen [Seattle Children' s Hospital, Department of Radiology, Seattle, WA (United States); Sugar, Naomi; Feldman, Kenneth [Seattle Children' s Hospital, Children' s Protection Program, Seattle, WA (United States); Marasigan, Joanne; Wambold, Nicolle [University of Washington, College of Arts and Sciences, Seattle, WA (United States)

2010-07-15

Rickets affects young infants and toddlers. However, there is a paucity of literature regarding the types of fractures that occur in rachitic patients. To evaluate the age of patients at which radiographically evident rickets occurs, and to characterize the age incidence and fractures that are observed in infants and toddlers with radiographically evident rickets. A retrospective study of children younger than 24 months was performed. Clinical data and radiographs were reviewed. Radiographs obtained within 1 month of the diagnosis were evaluated for the presence or absence of osteopenia, presence or absence of fraying-cupping, and presence and characterization of fractures. After exclusion criteria were applied, 45 children were included in the study. Children with rickets evident by radiograph were in the age range of 2-24 months. Fractures were present in 17.5% of the study group, exclusively in mobile infants and toddlers. Fracture types included transverse long bone fractures, anterior and anterior-lateral rib fractures, and metaphyseal fractures. All fractures occurred exclusively in patients with severe, overtly evident rickets. Fractures occur in older infants and toddlers with overt rickets and can be seen by radiograph. Fractures do not resemble high-risk non-accidental trauma fractures. (orig.)

Wood density and anatomy of three Eucalyptus species: implications for hydraulic conductivity

OpenAIRE

Antonio J. Barotto; Silvia Monteoliva; Javier Gyenge; Alejandro Martínez-Meier; Karen Moreno; Natalia Tesón; María Elena Fernández

2017-01-01

Aim of the study: To characterize wood anatomical traits of three Eucalyptus species that differ in wood density and ecological requirements, and to examine the relationships between some anatomical features, wood density, and theoretical xylem hydraulic conductivity (Ks). Area of study: We analyzed 86 trees from three sites of Argentina (Entre Ríos and Buenos Aires Provinces). Methods: The sampled trees were Eucalyptus globulus, E. grandis and E. viminalis ranging from 11 to 15 years...

Employing Eigenvalue Ratios to Generate Prior Fracture-like Features for Stochastic Hydrogeophysical Characterization of a Fractured Aquifer System

Science.gov (United States)

Brewster, J.; Oware, E. K.

2017-12-01

Groundwater hosted in fractured rocks constitutes almost 65% of the principal aquifers in the US. The exploitation and contaminant management of fractured aquifers require fracture flow and transport modeling, which in turn requires a detailed understanding of the structure of the aquifer. The widely used equivalent porous medium approach to modeling fractured aquifer systems is inadequate to accurately predict fracture transport processes due to the averaging of the sharp lithological contrast between the matrix and the fractures. The potential of geophysical imaging (GI) to estimate spatially continuous subsurface profiles in a minimally invasive fashion is well proven. Conventional deterministic GI strategies, however, produce geologically unrealistic, smoothed-out results due to commonly enforced smoothing constraints. Stochastic GI of fractured aquifers is becoming increasing appealing due to its ability to recover realistic fracture features while providing multiple likely realizations that enable uncertainty assessment. Generating prior spatial features consistent with the expected target structures is crucial in stochastic imaging. We propose to utilize eigenvalue ratios to resolve the elongated fracture features expected in a fractured aquifer system. Eigenvalues capture the major and minor directions of variability in a region, which can be employed to evaluate shape descriptors, such as eccentricity (elongation) and orientation of features in the region. Eccentricity ranges from zero to one, representing a circularly sharped to a line feature, respectively. Here, we apply eigenvalue ratios to define a joint objective parameter consisting of eccentricity (shape) and direction terms to guide the generation of prior fracture-like features in some predefined principal directions for stochastic GI. Preliminary unconditional, synthetic experiments reveal the potential of the algorithm to simulate prior fracture-like features. We illustrate the strategy with a

Geophysical methods for fracture characterization in and around potential sites for nuclear waste disposal

International Nuclear Information System (INIS)

Majer, E.L.; Lee, K.H.; Morrison, H.F.

1992-08-01

Historically, geophysical methods have been used extensively to successfully explore the subsurface for petroleum, gas, mineral, and geothermal resources. Their application, however, for site characterization, and monitoring the performance of near surface waste sites or repositories has been somewhat limited. Presented here is an overview of the geophysical methods that could contribute to defining the subsurface heterogeneity and extrapolating point measurements at the surface and in boreholes to volumetric descriptions in a fractured rock. In addition to site characterization a significant application of geophysical methods may be in performance assessment and in monitoring the repository to determine if the performance is as expected

Characterizing Fracture Property Using Resistivity Measured at Different Frequencies

Energy Technology Data Exchange (ETDEWEB)

Horne, Roland N. [Stanford Univ., CA (United States); Li, Kewen [Stanford Univ., CA (United States)

2014-09-30

The objective was to develop geophysical approaches to detecting and evaluating the fractures created or existing in EGS and other geothermal reservoirs by measuring the resistivity at different frequencies. This project has been divided into two phases: Phase I (first year): Proof of Concept – develop the resistivity approach and verify the effect of frequency on the resistivity in rocks with artificial or natural fractures over a wide range of frequencies. Phase II: Prototyping Part 1 (second year): measure the resistivity in rocks with fractures of different apertures, different length, and different configurations at different frequencies. Part 2 (third year): develop mathematical models and the resistivity method; infer the fracture properties using the measured resistivity data.

Competitive outcomes between wood-decaying fungi are altered in burnt wood.

Science.gov (United States)

Edman, Mattias; Eriksson, Anna-Maria

2016-06-01

Fire is an important disturbance agent in boreal forests where it creates a wide variety of charred and other types of heat-modified dead wood substrates, yet how these substrates affect fungal community structure and development within wood is poorly understood. We allowed six species of wood-decaying basidiomycetes to compete in pairs in wood-discs that were experimentally burnt before fungal inoculation. The outcomes of interactions in burnt wood differed from those in unburnt control wood for two species:Antrodia sinuosanever lost on burnt wood and won over its competitor in 67% of the trials compared to 40% losses and 20% wins on unburnt wood. In contrast, Ischnoderma benzoinumwon all interactions on unburnt wood compared to 33% on burnt wood. However, the responses differed depending on the identity of the competing species, suggesting an interaction between competitor and substrate type. The observed shift in competitive balance between fungal species probably results from chemical changes in burnt wood, but the underlying mechanism needs further investigation. Nevertheless, the results indicate that forest fires indirectly structure fungal communities by modifying dead wood, and highlight the importance of fire-affected dead wood substrates in boreal forests. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Tensile fracture and thermal conductivity characterization of toughened epoxy/CNT nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Balakrishnan, Anandh [School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019 (United States); Saha, Mrinal C., E-mail: msaha@ou.edu [School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019 (United States)

2011-01-25

Rubber toughened epoxy/CNT nanocomposites were manufactured at different weight percents between 0 and 1% of multiwall carbon nanotube (MWNT) using a high intensity ultrasonic liquid processor with a titanium probe. Mechanical properties of manufactured dog bone samples were measured in tension and the results indicated a maximum of 23% increase in the elastic modulus at 0.6% by weight of MWNT. However, the fracture strength showed a maximum decrease of about 11% as a function of increasing MWNT loading. Scanning Electron Microscopy (SEM) images from the neat samples revealed a distinct circular pit at the top left edge of the specimen with an overall tearing deformation causing the fracture paths. Comparatively, all nanocomposite samples on an average seemed to show a prominent brittle fracture with little or no evidence of circular pit formation. The amount of tearing deformation seemed to be enhanced in the nanocomposite specimens as compare to the neat ones. Finally, Transmission Electron Microscopy images indicated that different states of dispersion exist in all of the nanocomposite samples. The data showed that agglomeration of nanotubes increases as a function of weight percent. In addition to mechanical property characterization, thermal conductivity of all the samples was determined as a function of temperature between 30 deg. C and 100 deg. C using the 3{omega} method. The tested samples showed an almost 16% increase in thermal conductivity. The minimal enhancement in thermal conductivity has been analyzed from the standpoint of the Effective Medium Theory. Interfacial thermal resistances exhibit no order of magnitude changes explaining the conductivity results.

Tensile fracture and thermal conductivity characterization of toughened epoxy/CNT nanocomposites

International Nuclear Information System (INIS)

Balakrishnan, Anandh; Saha, Mrinal C.

2011-01-01

Rubber toughened epoxy/CNT nanocomposites were manufactured at different weight percents between 0 and 1% of multiwall carbon nanotube (MWNT) using a high intensity ultrasonic liquid processor with a titanium probe. Mechanical properties of manufactured dog bone samples were measured in tension and the results indicated a maximum of 23% increase in the elastic modulus at 0.6% by weight of MWNT. However, the fracture strength showed a maximum decrease of about 11% as a function of increasing MWNT loading. Scanning Electron Microscopy (SEM) images from the neat samples revealed a distinct circular pit at the top left edge of the specimen with an overall tearing deformation causing the fracture paths. Comparatively, all nanocomposite samples on an average seemed to show a prominent brittle fracture with little or no evidence of circular pit formation. The amount of tearing deformation seemed to be enhanced in the nanocomposite specimens as compare to the neat ones. Finally, Transmission Electron Microscopy images indicated that different states of dispersion exist in all of the nanocomposite samples. The data showed that agglomeration of nanotubes increases as a function of weight percent. In addition to mechanical property characterization, thermal conductivity of all the samples was determined as a function of temperature between 30 deg. C and 100 deg. C using the 3ω method. The tested samples showed an almost 16% increase in thermal conductivity. The minimal enhancement in thermal conductivity has been analyzed from the standpoint of the Effective Medium Theory. Interfacial thermal resistances exhibit no order of magnitude changes explaining the conductivity results.

Extraction and characterization of cellulose nano whiskers from balsa wood

International Nuclear Information System (INIS)

Morelli, Carolina L.; Bretas, Rosario E.S.; Marconcini, Jose M.; Pereira, Fabiano V.; Branciforti, Marcia C.

2011-01-01

In this study cellulose nano whiskers were obtained from balsa wood. For this purpose, fibers of balsa wood were subjected to hydrolysis reactions for lignin and hemi cellulose digestion and acquisition of nano-scale cellulose. Cellulose nano crystals obtained had medium length and thickness of 176 nm and 7 nm respectively. Infrared spectroscopy and x-ray diffraction showed that the process used for extracting nano whiskers could digest nearly all the lignin and hemi cellulose from the balsa fiber and still preserve the aspect ratio and crystallinity, satisfactory enough for future application in polymer nano composites. Thermogravimetry showed that the onset temperature of thermal degradation of cellulose nano crystals (226 degree C) was higher than the temperature of the balsa fiber (215 degree C), allowing its use in molding processes with many polymers from the molten state.(author)

Ductile fracture theories for pressurised pipes and containers

Science.gov (United States)

Erdogan, F.

1976-01-01

Two mechanisms of fracture are distinguished. Plane strain fractures occur in materials which do not undergo large-scale plastic deformations prior to and during a possible fracture deformation. Plane stress or high energy fractures are generally accompanied by large inelastic deformations. Theories for analyzing plane stress are based on the concepts of critical crack opening stretch, K(R) characterization, J-integral, and plastic instability. This last is considered in some detail. The ductile fracture process involves fracture initiation followed by a stable crack growth and the onset of unstable fracture propagation. The ductile fracture propagation process may be characterized by either a multiparameter (discrete) model, or some type of a resistance curve which may be considered as a continuous model expressed graphically. These models are studied and an alternative model is also proposed for ductile fractures which cannot be modeled as progressive crack growth phenomena.

Experimental Investigation of Moisture Driven Fracture in Solid Wood

DEFF Research Database (Denmark)

Larsen, Finn; Ormarsson, Sigurdur; Olesen, John Forbes

2010-01-01

Solid timber products, containing both heartwood and sapwood, often have a high tendency to crack during the drying process. This can cause severe loss of material for the saw-mills, especially for products with large cross sectional dimensions. The cracks (e.g. end-cracks) arise, in some cases......, early in the drying process and close again later in the process. It can be difficult to see the closed cracks with visual grading. This may result in too high grading of the damaged material which may cause problems for customers such as building and furniture industries. Moisture content (MC) in green...... wood varies within the cross section of a timber log. The MC of heartwood, for example, is considerable lower than the MC of sapwood. Shrinkage starts at different times within different parts of the cross section, which results in a complex state of strains and stresses. The moisture related crack...

Modification of the original color of the Eucalyptus grandis wood by heat treatments

Directory of Open Access Journals (Sweden)

Rosilei Aparecida Garcia

2014-09-01

Full Text Available The objective of this study was to determine the modification of original color of Eucalyptus grandis Hill ex. Maiden wood after heat-treatment. Wood samples were heat-treated under different temperatures (180, 200, 215 and 230ºC and time conditions (15 minutes, 2 and 4 hours. Color analysis were performed on the CIE L*a*b* system by using a Color Eye XTH-X-Rite 200d spectrophotometer. All heat treatments promoted an alteration of the original color of wood. Heat-treated woods presented lower L* (lightness values than untreated wood (control, characterizing the wood darkness, mainly for more severe conditions of temperature and time. Chromatic coordinates (a* and b* showed different behaviors depending on the temperature-time combination. The modification of the original color of the wood allowed the creation of new color patterns, which can add greater value to the studied wood.

Characterizing hydraulic fractures in shale gas reservoirs using transient pressure tests

Directory of Open Access Journals (Sweden)

Cong Wang

2015-06-01

This work presents an unconventional gas reservoir simulator and its application to quantify hydraulic fractures in shale gas reservoirs using transient pressure data. The numerical model incorporates most known physical processes for gas production from unconventional reservoirs, including two-phase flow of liquid and gas, Klinkenberg effect, non-Darcy flow, and nonlinear adsorption. In addition, the model is able to handle various types and scales of fractures or heterogeneity using continuum, discrete or hybrid modeling approaches under different well production conditions of varying rate or pressure. Our modeling studies indicate that the most sensitive parameter of hydraulic fractures to early transient gas flow through extremely low permeability rock is actually the fracture-matrix contacting area, generated by fracturing stimulation. Based on this observation, it is possible to use transient pressure testing data to estimate the area of fractures generated from fracturing operations. We will conduct a series of modeling studies and present a methodology using typical transient pressure responses, simulated by the numerical model, to estimate fracture areas created or to quantity hydraulic fractures with traditional well testing technology. The type curves of pressure transients from this study can be used to quantify hydraulic fractures in field application.

Fabrication of a superhydrophobic surface on a wood substrate

Science.gov (United States)

Wang, Shuliang; Shi, Junyou; Liu, Changyu; Xie, Cheng; Wang, Chengyu

2011-09-01

A layer of lamellar superhydrophobic coating was fabricated on a wood surface through a wet chemical process. The superhydrophobic property of the wood surface was measured by contact angle (CA) measurements. The microstructure and chemical composition of the superhydrophobic coating were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). An analytical characterization revealed that the microscale roughness of the lamellar particles was uniformly distributed on the wood surface and that a zinc stearate monolayer (with the hydrophobic groups oriented outward) formed on the ZnO surface as the result of the reaction between stearic acid and ZnO. This process transformed the wood surface from hydrophilic to superhydrophobic: the water contact angle of the surface was 151°, and the sliding angle was less than 5°.

Wood density and anatomy of three Eucalyptus species: implications for hydraulic conductivity

OpenAIRE

Barotto, Antonio J.; Monteoliva, Silvia; Gyenge, Javier; Martínez-Meier, Alejandro; Moreno, Karen; Tesón, Natalia; Fernández, María Elena

2017-01-01

Aim of the study: To characterize wood anatomical traits of three Eucalyptus species that differ in wood density and ecological requirements, and to examine the relationships between some anatomical features, wood density, and theoretical xylem hydraulic conductivity (Ks).Area of study: We analyzed 86 trees from three sites of Argentina (Entre Ríos and Buenos Aires Provinces).Methods: The sampled trees were Eucalyptus globulus, E. grandis and E. viminalis ranging from 11 to 15 years old. One ...

Potential wood protection strategies using physiological requirements of wood degrading fungi

NARCIS (Netherlands)

Sailer, M.F.; Etten, B.D. van

2004-01-01

Due to the increasing restrictions in the use of wood preserving biocides a number of potential biocide free wood preserving alternatives are currently assessed. Wood degrading fungi require certain conditions in the wood in order to be able to use wood as a food source. This paper discusses the

Femtosecond laser machining for characterization of local mechanical properties of biomaterials: a case study on wood

Science.gov (United States)

Jakob, Severin; Pfeifenberger, Manuel J.; Hohenwarter, Anton; Pippan, Reinhard

2017-12-01

The standard preparation technique for micro-sized samples is focused ion beam milling, most frequently using Ga+ ions. The main drawbacks are the required processing time and the possibility and risks of ion implantation. In contrast, ultrashort pulsed laser ablation can process any type of material with ideally negligible damage to the surrounding volume and provides 4 to 6 orders of magnitude higher ablation rates than the ion beam technique. In this work, a femtosecond laser was used to prepare wood samples from spruce for mechanical testing at the micrometre level. After optimization of the different laser parameters, tensile and compressive specimens were produced from microtomed radial-tangential and longitudinal-tangential sections. Additionally, laser-processed samples were exposed to an electron beam prior to testing to study possible beam damage. The specimens originating from these different preparation conditions were mechanically tested. Advantages and limitations of the femtosecond laser preparation technique and the deformation and fracture behaviour of the samples are discussed. The results prove that femtosecond laser processing is a fast and precise preparation technique, which enables the fabrication of pristine biological samples with dimensions at the microscale.

Research on fracture analysis, groundwater flow and sorption processes in fractured rocks

Energy Technology Data Exchange (ETDEWEB)

Lee, Dae Ha [Korea Institute of Geology Mining and Materials, Taejon (Korea)

1998-12-01

Due to increasing demand for numerous industrial facilities including nuclear power plants and waste repositories, the feasibility of rocks masses as sites for the facilities has been a geological issue of concern. Rock masses, in general, comprises systems of fractures which can provide pathways for groundwater flow and may also affect the stability of engineered structures. such properties of fractures stimulate a synthetic study on (1) analyses of fracture systems, and (2) characterization of groundwater flow and sorption processes in fractured rocks to establish a preliminary model for assessing suitable sites for industrial facilities. The analyses of fracture systems cover (1) reconstruction of the Cenozoic tectonic movements and estimation of frequency indices for the Holocene tectonic movements, (2) determination of distributions and block movements of the Quaternary marine terraces, (3) investigation of lithologic and geotechnical nature of study area, and (4) examination of the Cenozoic volcanic activities and determination of age of the dike swarms. Using data obtained from above mentioned analyses along with data related to earthquakes and active faults, probabilistic approach is performed to determine various potential hazards which may result from the Quaternary or the Holocene tectonic movements. In addition, stepwise and careful integration of various data obtained from field works and laboratory experiments are carried out to analyze groundwater flow in fractures rocks as follows; (1) investigation of geological feature of the site, (2) identification and characterization of fracture systems using core and televiewer logs, (3) determination of conductive fractures using electrical conductivity, temperature, and flow logs, (4) identification of hydraulic connections between fractures using televiewer logs with tracer tests within specific zones. The results obtained from these processes allow a qualitative interpretation of groundwater flow patterns

Sound quality assessment of wood for xylophone bars.

Science.gov (United States)

Aramaki, Mitsuko; Baillères, Henri; Brancheriau, Loïc; Kronland-Martinet, Richard; Ystad, Sølvi

2007-04-01

Xylophone sounds produced by striking wooden bars with a mallet are strongly influenced by the mechanical properties of the wood species chosen by the xylophone maker. In this paper, we address the relationship between the sound quality based on the timbre attribute of impacted wooden bars and the physical parameters characterizing wood species. For this, a methodology is proposed that associates an analysis-synthesis process and a perceptual classification test. Sounds generated by impacting 59 wooden bars of different species but with the same geometry were recorded and classified by a renowned instrument maker. The sounds were further digitally processed and adjusted to the same pitch before being once again classified. The processing is based on a physical model ensuring the main characteristics of the wood are preserved during the sound transformation. Statistical analysis of both classifications showed the influence of the pitch in the xylophone maker judgement and pointed out the importance of two timbre descriptors: the frequency-dependent damping and the spectral bandwidth. These descriptors are linked with physical and anatomical characteristics of wood species, providing new clues in the choice of attractive wood species from a musical point of view.

Microscopic Characterization of Tensile and Shear Fracturing in Progressive Failure in Marble

Science.gov (United States)

Cheng, Yi; Wong, Louis Ngai Yuen

2018-01-01

Compression-induced tensile and shear fractures were reported to be the two fundamental fracture types in rock fracturing tests. This study investigates such tensile and shear fracturing process in marble specimens containing two different flaw configurations. Observations first reveal that the development of a tensile fracture is distinct from shear fracture with respect to their nucleation, propagation, and eventual formation in macroscale. Second, transgranular cracks and grain-scale spallings become increasingly abundant in shear fractures as loading increases, which is almost not observed in tensile fractures. Third, one or some dominant extensional microcracks are commonly observed in the center of tensile fractures, while such development of microcracks is almost absent in shear fractures. Microcracks are generally of a length comparable to grain size and distribute uniformly within the damage zone of the shear fracture. Fourth, the width of densely damaged zone in the shear fracture is nearly 10 times of that in the tensile fracture. Quantitative measurement on microcrack density suggests that (1) microcrack density in tensile and shear fractures display distinct characteristics with increasing loading, (2) transgranular crack density in the shear fracture decreases logarithmically with the distance away from the shear fracture center, and (3) whatever the fracture type, the anisotropy can only be observed for transgranular cracks with a large density, which partially explains why microcrack anisotropy usually tends to be unobvious until approaching peak stress in specimens undergoing brittle failure. Microcracking characteristics observed in this work likely shed light to some phenomena and conclusions generalized in seismological studies.

Characterizing Fractures Across the Astronaut Corps: Preliminary Findings from Population-Level Analysis

Science.gov (United States)

Rossi, Meredith M.; Charvat, Jacqueline; Sibonga, Jean; Sieker, Jeremy

2017-01-01

Despite evidence of bone loss during spaceflight and operational countermeasures to mitigate this loss, the subsequent risk of fracture among astronauts is not known. The physiologic process of diminished bone density and bone recovery during or following spaceflight is multifactorial. Such factors as age, sex, fracture history, and others may combine to increase fracture risk among astronauts. As part of the 2016 Bone Research and Clinical Advisory Panel (RCAP), the authors analyzed data collected on 338 NASA astronauts to describe the demographics, bone-relevant characteristics, and fracture history of the astronaut population. The majority of the population are male (n=286, 84.6%), have flown at least one mission (n=306, 90.5%), and were between the ages of 30 and 49 at first mission (n=296, 96.7% of those with at least one mission). Of the 338 astronauts, 241 (71.3%) experienced a fracture over the course of their lifetime. One hundred and five (43.5%) of these 241 astronauts only experienced a fracture prior to being selected into the Astronaut Corps, whereas 53 (22.0%) only experienced a fracture after selection as an astronaut. An additional 80 astronauts (33.2%) had both pre- and post-selection fractures. The remaining 3 astronauts had a fracture of unknown date, which could not be categorized as pre- or post-selection. Among the 133 astronauts with at least one post-selection fracture, males comprised 90.2% (n=120) compared to 84.5% of the entire Corps, and females accounted for 9.8% (n=13) compared to 15.4% of the Corps. Ninety-seven of the 133 astronauts with post-selection fractures (72.9%) had one fracture event, 22 (16.5%) had two fractures, and 14 (10.5%) had three or more fractures. Some astronauts with multiple fractures suffered these in a single event, such as an automobile accident. The 133 astronauts with a post-selection fracture accounted for a total of 188 fracture events. One hundred and four (78.2%) of astronauts with post

Temporal variation of VOC emission from solvent and water based wood stains

Science.gov (United States)

de Gennaro, Gianluigi; Loiotile, Annamaria Demarinis; Fracchiolla, Roberta; Palmisani, Jolanda; Saracino, Maria Rosaria; Tutino, Maria

2015-08-01

Solvent- and water-based wood stains were monitored using a small test emission chamber in order to characterize their emission profiles in terms of Total and individual VOCs. The study of concentration-time profiles of individual VOCs enabled to identify the compounds emitted at higher concentration for each type of stain, to examine their decay curve and finally to estimate the concentration in a reference room. The solvent-based wood stain was characterized by the highest Total VOCs emission level (5.7 mg/m3) that decreased over time more slowly than those related to water-based ones. The same finding was observed for the main detected compounds: Benzene, Toluene, Ethylbenzene, Xylenes, Styrene, alpha-Pinene and Camphene. On the other hand, the highest level of Limonene was emitted by a water-based wood stain. However, the concentration-time profile showed that water-based product was characterized by a remarkable reduction of the time of maximum and minimum emission: Limonene concentration reached the minimum concentration in about half the time compared to the solvent-based product. According to AgBB evaluation scheme, only one of the investigated water-based wood stains can be classified as a low-emitting product whose use may not determine any potential adverse effect on human health.

Characterization of the Oriskany and Berea Sandstones: Evaluating Biogeochemical Reactions of Potential Sandstone–Hydraulic Fracturing Fluid Interaction

Energy Technology Data Exchange (ETDEWEB)

Verba, Circe [National Energy Technology Lab. (NETL), Albany, OR (United States); Harris, Aubrey [National Energy Technology Lab. (NETL), Albany, OR (United States)

2016-07-07

, guar gum, and isopropanol]; 3) reviews the known research about the interactions between several hydraulic fracturing chemicals [e.g. polyacrylamide, ethylene glycol, poly(diallyldimethylammonium chloride), and glutaraldehyde] with the minerals (quartz, clay, pyrite, and carbonates) common to the lithologies of the Marcellus shale and its surrounding sandstones; and 4) characterizes the Berea sandstone and analyzes the physical and chemical effects of flowing guar gum through a Berea sandstone core.

Isolation and Rheological Characterization of Cellulose Nanofibrils (CNFs from Coir Fibers in Comparison to Wood and Cotton

Directory of Open Access Journals (Sweden)

Daran Yue

2018-03-01

Full Text Available In this report, the isolation and rheological characterization of cellulose nanofibrils from coir (CNFs-1 were studied and compared with the CNFs from wood (CNFs-2 and cotton (CNFs-3. Cellulose nanofibrils were isolated successfully from coir fibers by chemical treatments followed by ultrasonic fibrillation. During ultrasonic processing, the size and the crystal structure of the CNFs were influenced by the raw materials. In comparison to CNFs-2 and CNFs-3, CNFs-1 from coir fibers presented diverse advantages, such as sufficient fibrillation with a low diameter distribution, in the range of 2–4 nm and high crystallinity. In the dynamic rheology study of CNFs-1, elastic behavior was observed and maintained due to the formation of gel-like steady network structures, which could not be easily deconstructured by frequency shearing and temperature changing. All results indicated that coir fibers could be used as a valuable resource for the preparation of CNFs, which exhibited comparable properties with those isolated from wood, in regard to morphology and rheological properties. This work provides a basis for further advanced applications using the CNFs isolated from coir fibers.

Biomaterial based novel polyurethane adhesives for wood to wood and metal to metal bonding

Directory of Open Access Journals (Sweden)

Mitesh Ramanlal Patel

2009-01-01

Full Text Available Polyurethane adhesives made from synthetic chemicals are non-biodegradable, costly and difficult to find raw materials from local market. To avoid solid pollution problem, cost effectiveness and easy availability of raw materials, biomaterials based polyurethane adhesives are used in current industrial interest. Direct use of castor oil in polyurethane adhesive gives limited hardness. Modification on active sites of castor oil to utilize double bond of unsaturated fatty acid and carboxyl group yields new modified or activated polyols, which can be utilized for polyurethane adhesive formulation. In view of this, we have synthesized polyurethane adhesives from polyester polyols, castor oil based polyols and epoxy based polyols with Isocyanate adducts based on castor oil and trimethylolpropane. To study the effects of polyurethane adhesive strength (i.e. lap shear strength on wood-to-wood and metal-to-metal bonding through various types of polyols, cross-linking density, isocyanate adducts and also to compare adhesive strength between wood to wood and metal to metal surface. These polyols and polyurethanes were characterized through GPC, NMR and IR-spectroscopy, gel and surface drying time. Thermal stability of PU adhesives was determined under the effect of cross-linking density (NCO/OH ratio. The NCO/OH ratio (1.5 was optimized for adhesives as the higher NCO/OH ratio (2.0 increasing cross-linking density and decreases adhesion. Lower NCO/OH ratio (1.0 provideslow cross-linking density and low strength of adhesives.

Environment-friendly wood fibre composite with high bonding strength and water resistance

Science.gov (United States)

Ji, Xiaodi; Dong, Yue; Nguyen, Tat Thang; Chen, Xueqi; Guo, Minghui

2018-04-01

With the growing depletion of wood-based materials and concerns over emissions of formaldehyde from traditional wood fibre composites, there is a desire for environment-friendly binders. Herein, we report a green wood fibre composite with specific bonding strength and water resistance that is superior to a commercial system by using wood fibres and chitosan-based adhesives. When the mass ratio of solid content in the adhesive and absolute dry wood fibres was 3%, the bonding strength and water resistance of the wood fibre composite reached the optimal level, which was significantly improved over that of wood fibre composites without adhesive and completely met the requirements of the Chinese national standard GB/T 11718-2009. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) characterizations revealed that the excellent performance of the binder might partly be due to the amide linkages and hydrogen bonding between wood fibres and the chitosan-based adhesive. We believe that this strategy could open new insights into the design of environment-friendly wood fibre composites with high bonding strength and water resistance for multifunctional applications.

Wood Identification of 18th Century Furniture. Interpreting Wood Naming Inventoires

Directory of Open Access Journals (Sweden)

Rocio Astrid BERNAL

2011-09-01

Full Text Available The 18th century Portuguese church furniture represents an extraordinary richness recognised worldwide, which demands safeguarding and valorisation. The identification of the wood of furniture artworks is the most important component for its comprehension and preservation. In this work wood anatomical characters of an 18th century Portuguese decorative furniture set from the Colegiada de São Martinho de Cedofeita, in Porto, were analysed to identify the woods used for manufacturing and to clarify their common names. Furthermore, the objectives were to recognise some of the criteria for choice of wood as well as the source of each wood. The woods identified from 16 fragments belong to Apuleia sp., Acacia sp., Neolamarckia sp. and Castanea sativa. Apuleia sp. and Acacia sp. woods most likely arrived from Brazil, while the Neolamarckia sp. woods likely arrived from India and the C. sativa woods from Portugal. The results are in accordance with the known Portuguese colonial sea routes of the 15th -18th centuries. Interestingly the terms found in the inventories can refer to finishing methods instead to the name of the woods, as for instance “oil wood” can refer to “oiled wood” or “linseed oiled wood”. The species choice may be related to the mechanical properties of the wood as well as the original tree size. Two large planks of Acacia sp. were used for the top of the “Portuguese arcaz”, and Apuleia sp. was found on main structural elements of this set of furniture, suggesting that wood colour was also important. Woods from Neolamarckia sp. and C. sativa, were also identified, being Castanea wood present only in the most recent pieces of the furniture set.

Energy wood. Part 2b: Wood pellets and pellet space-heating systems

International Nuclear Information System (INIS)

Nussbaumer, T.

2002-01-01

The paper gives an overview on pellet utilization including all relevant process steps: Potential and properties of saw dust as raw material, pellet production with drying and pelletizing, standardization of wood pellets, storage and handling of pellets, combustion of wood pellets in stoves and boilers and applications for residential heating. In comparison to other wood fuels, wood pellets show several advantages: Low water content and high heating value, high energy density, and homogeneous properties thus enabling stationary combustion conditions. However, quality control is needed to ensure constant properties of the pellets and to avoid the utilization of contaminated raw materials for the pellet production. Typical data of efficiencies and emissions of pellet stoves and boilers are given and a life cycle analysis (LCA) of wood pellets in comparison to log wood and wood chips is described. The LCA shows that wood pellets are advantageous thanks to relatively low emissions. Hence, the utilization of wood pellet is proposed as a complementary technology to the combustion of wood chips and log wood. Finally, typical fuel cost of wood pellets in Switzerland are given and compared with light fuel oil. (author)

Wood-related occupations, wood dust exposure, and sinonasal cancer.

Science.gov (United States)

Hayes, R B; Gerin, M; Raatgever, J W; de Bruyn, A

1986-10-01

A case-control study was conducted to examine the relations between type of woodworking and the extent of wood dust exposure to the risks for specific histologic types of sinonasal cancer. In cooperation with the major treatment centers in the Netherlands, 116 male patients newly diagnosed between 1978 and 1981 with primary malignancies of epithelial origin of this site were identified for study. Living controls were selected from the municipal registries, and deceased controls were selected from the national death registry. Interviews were completed for 91 (78%) cases and 195 (75%) controls. Job histories were coded by industry and occupation. An index of exposure was developed to classify the extent of occupational exposure to wood dust. When necessary, adjustment was made for age and usual cigarette use. The risk for nasal adenocarcinoma was elevated by industry for the wood and paper industry (odds ratio (OR) = 11.9) and by occupation for those employed in furniture and cabinet making (OR = 139.8), in factory joinery and carpentry work (OR = 16.3), and in association with high-level wood dust exposure (OR = 26.3). Other types of nasal cancer were not found to be associated with wood-related industries or occupations. A moderate excess in risk for squamous cell cancer (OR = 2.5) was associated with low-level wood dust exposure; however, no dose-response relation was evident. The association between wood dust and adenocarcinoma was strongest for those employed in wood dust-related occupations between 1930 and 1941. The risk of adenocarcinoma did not appear to decrease for at least 15 years after termination of exposure to wood dust. No cases of nasal adenocarcinoma were observed in men whose first exposure to wood dust occurred after 1941.

Oral-motor and electromyographic characterization of patients submitted to open a nd closed reductions of mandibular condyle fracture.

Science.gov (United States)

Silva, Amanda Pagliotto da; Sassi, Fernanda Chiarion; Andrade, Claudia Regina Furquim de

To characterize the oral-motor system of adults with mandibular condyle facture comparing the performance of individuals submitted to open reduction with internal fixation (ORIF) and closed reduction with mandibulomaxillary fixation (CRMMF). Study participants were 26 adults divided into three groups: G1 - eight individuals submitted to ORIF for correction of condyle fracture; G2 - nine individuals submitted to CRMMF for correction of condyle fracture; CG - nine healthy volunteers with no alterations of the orofacial myofunctional system. All participants underwent the same clinical protocol: assessment of the orofacial myofunctional system; evaluation of the mandibular range of motion; and surface electromyography (sEMG) of the masticatory muscles. Results indicated that patients with condyle fractures from both groups presented significant differences compared with those from the control group in terms of mobility of the oral-motor organs, mastication, and deglutition. Regarding the measures obtained for mandibular movements, participants with facial fractures from both groups showed significant differences compared with those from the control group, indicating greater restrictions in mandibular motion. As for the analysis of sEMG results, G1 patients presented more symmetrical masseter activation during the task of maximal voluntary teeth clenching. Patients with mandibular condyle fractures present significant deficits in posture, mobility, and function of the oral-motor system. The type of medical treatment does not influence the results of muscle function during the first six months after fracture reduction. Individuals submitted to ORIF of the condyle fracture present more symmetrical activation of the masseter muscle.

The application of vertical seismic profiling and cross-hole tomographic imaging for fracture characterization at Yucca Mountain

International Nuclear Information System (INIS)

Majer, E.L.; Peterson, J.E.; Tura, M.A.; McEvilly, T.V.

1990-01-01

In order to obtain the necessary characterization for the storage of nuclear waste, much higher resolution of the features likely to affect the transport of radionuclides will be required than is normally achieved in conventional surface seismic reflection used in the exploration and characterization of petroleum and geothermal resources. Because fractures represent a significant mechanical anomaly seismic methods using are being investigated as a means to image and characterize the subsurface. Because of inherent limitations in applying the seismic methods solely from the surface, state-of-the-art borehole methods are being investigated to provide high resolution definition within the repository block. Therefore, Vertical Seismic Profiling (VSP) and cross-hole methods are being developed to obtain maximum resolution of the features that will possible affect the transport of fluids. Presented here will be the methods being developed, the strategy being pursued, and the rational for using VSP and crosshole methods at Yucca Mountain. The approach is intended to be an integrated method involving improvements in data acquisition, processing, and interpretation as well as improvements in the fundamental understanding of seismic wave propagation in fractured rock. 33 refs., 4 figs

Effect of cement/wood ratios and wood storage conditions on hydration temperature, hydration time, and compressive strength of wood-cement mixtures

Science.gov (United States)

Andy W.C. Lee; Zhongli Hong; Douglas R. Phillips; Chung-Yun Hse

1987-01-01

This study investigated the effect of cement/wood ratios and wood storage conditions on hydration temperature, hydration time, and compressive strength of wood-cement mixtures made from six wood species: southern pine, white oak, southern red oak, yellow-poplar, sweetgum, and hickory. Cement/wood ratios varied from 13/1 to 4/1. Wood storage conditions consisted of air-...

Geologic characterization of fractures as an aid to hydrologic modeling of the SCV block at the Stripa mine

International Nuclear Information System (INIS)

Martel, S.

1992-04-01

A series of hydrologic tests have been conducted at the Stripa research mine in Sweden to develop hydrologic characterization techniques for rock masses in which fractures form the primary flow paths. The structural studies reported here were conducted to aid in the hydrologic examination of a cubic block of granite with dimensions of 150 m on a side. This block (the SCV block) is located between the 310- and 460-m depth levels at the Stripa mine. This report describes and interprets the fracture system geology at Stripa as revealed in drift exposures, checks the interpretive model against borehole records and discusses the hydrologic implication of the model, and examines the likely effects of stress redistribution around a drift (the Validation drift) on inflow to the drift along a prominent fracture zone. (72 refs.) (au)

Hydraulic fracture propagation modeling and data-based fracture identification

Science.gov (United States)

Zhou, Jing

Successful shale gas and tight oil production is enabled by the engineering innovation of horizontal drilling and hydraulic fracturing. Hydraulically induced fractures will most likely deviate from the bi-wing planar pattern and generate complex fracture networks due to mechanical interactions and reservoir heterogeneity, both of which render the conventional fracture simulators insufficient to characterize the fractured reservoir. Moreover, in reservoirs with ultra-low permeability, the natural fractures are widely distributed, which will result in hydraulic fractures branching and merging at the interface and consequently lead to the creation of more complex fracture networks. Thus, developing a reliable hydraulic fracturing simulator, including both mechanical interaction and fluid flow, is critical in maximizing hydrocarbon recovery and optimizing fracture/well design and completion strategy in multistage horizontal wells. A novel fully coupled reservoir flow and geomechanics model based on the dual-lattice system is developed to simulate multiple nonplanar fractures' propagation in both homogeneous and heterogeneous reservoirs with or without pre-existing natural fractures. Initiation, growth, and coalescence of the microcracks will lead to the generation of macroscopic fractures, which is explicitly mimicked by failure and removal of bonds between particles from the discrete element network. This physics-based modeling approach leads to realistic fracture patterns without using the empirical rock failure and fracture propagation criteria required in conventional continuum methods. Based on this model, a sensitivity study is performed to investigate the effects of perforation spacing, in-situ stress anisotropy, rock properties (Young's modulus, Poisson's ratio, and compressive strength), fluid properties, and natural fracture properties on hydraulic fracture propagation. In addition, since reservoirs are buried thousands of feet below the surface, the

Wood pellet seminar

International Nuclear Information System (INIS)

Aarniala, M.; Puhakka, A.

2001-01-01

The objective of the wood pellet seminar, arranged by OPET Finland and North Karelia Polytechnic, was to deliver information on wood pellets, pellet burners and boilers, heating systems and building, as well as on the activities of wood energy advisors. The first day of the seminar consisted of presentations of equipment and products, and of advisory desks for builders. The second day of the seminar consisted of presentations held by wood pellet experts. Pellet markets, the economy and production, the development of the pellet markets and their problems (in Austria), the economy of heating of real estates by different fuel alternatives, the production, delivery and marketing of wood pellets, the utilization of wood pellet in different utilization sites, the use of wood pellets in detached houses, pellet burners and fireplaces, and conversion of communal real estate houses to use wood pellets were discussed in the presentations. The presentations held in the third day discussed the utilization of wood pellets in power plants, the regional promotion of the production and the use of pellets. The seminar consisted also of visits to pellet manufacturing plant and two pellet burning heating plants

Pristine Early Eocene wood buried deeply in kimberlite from northern Canada.

Science.gov (United States)

Wolfe, Alexander P; Csank, Adam Z; Reyes, Alberto V; McKellar, Ryan C; Tappert, Ralf; Muehlenbachs, Karlis

2012-01-01

We report exceptional preservation of fossil wood buried deeply in a kimberlite pipe that intruded northwestern Canada's Slave Province 53.3±0.6 million years ago (Ma), revealed during excavation of diamond source rock. The wood originated from forest surrounding the eruption zone and collapsed into the diatreme before resettling in volcaniclastic kimberlite to depths >300 m, where it was mummified in a sterile environment. Anatomy of the unpermineralized wood permits conclusive identification to the genus Metasequoia (Cupressaceae). The wood yields genuine cellulose and occluded amber, both of which have been characterized spectroscopically and isotopically. From cellulose δ(18)O and δ(2)H measurements, we infer that Early Eocene paleoclimates in the western Canadian subarctic were 12-17°C warmer and four times wetter than present. Canadian kimberlites offer Lagerstätte-quality preservation of wood from a region with limited alternate sources of paleobotanical information.

kISMET: Stress and fracture characterization in a deep mine

Science.gov (United States)

Oldenburg, C. M.; Dobson, P. F.; Daley, T. M.; Birkholzer, J. T.; Cook, P. J.; Ajo Franklin, J. B.; Rutqvist, J.; Siler, D.; Kneafsey, T. J.; Nakagawa, S.; Wu, Y.; Guglielmi, Y.; Ulrich, C.; Marchesini, P.; Wang, H. F.; Haimson, B. C.; Sone, H.; Vigilante, P.; Roggenthen, W.; Doe, T.; Lee, M.; Mattson, E.; Huang, H.; Johnson, T. C.; Morris, J.; White, J. A.; Johnson, P. A.; Coblentz, D. D.; Heise, J.

2016-12-01

We are developing a community facility called kISMET (permeability (k) and Induced Seismicity Management for Energy Technologies) at the Sanford Underground Research Facility (SURF) in Lead, SD. The purpose of kISMET is to investigate stress and the effects of rock fabric on hydraulic fracturing. Although findings from kISMET may have broad applications that inform stress and fracturing in anisotropic rock, results will be most applicable to improving control of hydraulic fracturing for enhanced geothermal systems (EGS) in crystalline rock. At the kISMET site on the 4850 ft (1480 m depth) level of SURF, we have drilled and cored an array of nearly vertical boreholes in Precambrian phyllite. The array consists of four 50-m deep monitoring boreholes surrounding one 100-m deep borehole forming a 6 m-wide five-spot pattern at a depth of 1530 m. Previous investigations of the stress field at SURF suggest that the principal stress s1 is nearly vertical. By aligning the kISMET boreholes approximately with σ1, fractures created in the center borehole should in theory be perpendicular to σ3, the least principal horizontal stress. But the phyllite at kISMET has a strong fabric (foliation) that could influence fracturing. Stress measurements and stimulation using hydraulic fracturing will be carried out in the center borehole using a straddle packer and high-pressure pump. We will use an impression packer and image logs after stress testing and stimulation to determine fracture orientation and extent at the center borehole. In order to study the control of stress, rock fabric, and stimulation approach on size, aperture, and orientation of hydraulic fractures, we will carefully monitor the stress measurements and stimulation. For example, we will use continuous active source seismic (CASSM) in two of the monitoring boreholes to measure changes in seismic-wave velocity as water fills the fracture. Second, near real-time electrical resistance tomography (ERT) will be used in

Projected wood energy impact on US forest wood resources

Energy Technology Data Exchange (ETDEWEB)

Skog, K.E. [USDA Forest Service, Madison, WI (United States)

1993-12-31

The USDA Forest Service has developed long-term projections of wood energy use as part of a 1993 assessment of demand for and supply of resources from forest and range lands in the United States. To assess the impact of wood energy demand on timber resources, a market equilibrium model based on linear programming was developed to project residential, industrial, commercial, and utility wood energy use from various wood energy sources: roundwood from various land sources, primary wood products mill residue, other wood residue, and black liquor. Baseline projections are driven by projected price of fossil fuels compared to price of wood fuels and the projected increase in total energy use in various end uses. Wood energy use is projected to increase from 2.67 quad in 1986 to 3.5 quad in 2030 and 3.7 quad in 2040. This is less than the DOE National Energy Strategy projection of 5.5 quad in 2030. Wood energy from forest sources (roundwood) is projected to increase from 3.1 billion (10{sup 9}) ft{sup 3} in 1986 to 4.4. billion ft{sup 3} in 2030 and 4.8 billion ft{sup 3} in 2040 (88, 124 and 136 million m{sup 3}, respectively). This rate of increase of roundwood use for fuel -- 0.8 percent per year -- is virtually the same as the projected increase rate for roundwood for pulpwood. Pulpwood roundwood is projected to increase from 4.2 billion ft{sup 3} in 1986 to 6.0 billion ft{sup 3} in 2030 and 6.4 billion ft{sup 3} in 2040 (119, 170 and 183 million m{sup 3}, respectively).

SYNTAXONOMY OF HY GROPHILOUS WOODS OF THE ALNO-QUERCION ROBORIS

Directory of Open Access Journals (Sweden)

S. BRULLO

1999-01-01

Full Text Available A syntaxonomical revision of the hygrophilous woods occurring in marshy places of the flood-plains from SE Europe is given. This vegetation is included in the Alno-Quercion roboris, alliance of the Populetalia albae, which comprises numerous associations characterized by the dominance of hard-wood trees, such as Quercus robur, Fraxinus oxycarpa, Ulmus minor, Alnus glutinosa, etc. For each association the synonyms, nomenclature type, diagnostic species, ecology, structure and chorology are given.

Colorimetry as grouping tool of eucalyptus clones wood

Directory of Open Access Journals (Sweden)

Márcio da Fonseca Martins

2015-12-01

Full Text Available The homogeneity of wood color in a batch to be marketed is of fundamental importance, as it will reflect in products quality resulting from its processing. In this context, this study aimed to evaluate, through colorimetric technique, the colorimetric parameters of Eucalyptus spp. wood from 25 clones and classify them into groups, according to color similarity degree. It was determined the lightness (L*, red-green color coordinate (a*, yellow-blue chromatic coordinate (b*, chromaticity (C* and ink angle (h. Radial and tangential faces and three positions in the radial direction were characterized using a colorimeter. Comparing to tangential planes, the results showed that radial plane presented larger values of L* and h in wood near the bark. Furthermore, it was observed higher values of L* in samples from intermediate radial positions. Finally, it was found that, as radial growth ocurred, developed timber showed less intense yellow shades. The definition of the wood color tones will be useful in timber market in the homogenization of their products, which will facilitate their marketing.

Characterization and quantification of preferential flow in fractured rock systems, using resistivity tomography

CSIR Research Space (South Africa)

May, F

2010-11-01

Full Text Available , N Jovanovic2 and A Rozanov1 University of Stellenbosch1 and Council for Scientific and Industrial Research (CSIR)2 Characterization and quantification of preferential flow in fractured rock systems, using resistivity tomography Introduction... of slow and fast flowing pathways. Materials and Methods TABLE 1 DATE, TIME AND WEATHER CONDITIONS DURING RESISTIVITY TOMOGRAPHY SURVEY Survey No. Date Start time End time Precipitation (mm) Description KB001 8/27/2010 12H00 13H40 0.0 Sunny KB002 8...

Eco-friendly materials for large area piezoelectronics: self-oriented Rochelle salt in wood

Science.gov (United States)

Lemaire, E.; Ayela, C.; Atli, A.

2018-02-01

Upgraded biodegradable piezoelectric composite materials elaborated by incorporation of Rochelle salt (RS, Sodium potassium tartrate tetrahydrate) in wood were reported. RS crystals, known as the first discovered piezoelectric material, were grown in the micro-cavities of wood, having naturally a tubular structure, by soaking the wood into RS saturated water. Since most of the cavities in wood are oriented in the same direction, the piezoelectric effect was improved when the cavities were filled by RS crystals. The mechanical, structural and piezoelectric properties of RS incorporated wood composite samples were characterized. Both direct and converse piezoelectric effects are illustrated. The wood-base composite exhibits an effective piezoelectric constant d 33 of 11 pC N-1. Also, the flexural strength and modulus of elasticity were enhanced by inserting RS into the wood, nevertheless the samples became more brittle. The wood-based piezoelectric samples prepared in this work can be used as actuators, sensors or energy harvesters. The process developed here permits us to manufacture large area piezoelectric devices which are environmentally and economically unsurpassed.

Finishing of wood

Science.gov (United States)

R. Sam Williams

1999-01-01

The primary function of any wood finish (paint, varnish, and stain, for example) is to protect the wood surface, help maintain a certain appearance, and provide a cleanable surface. Although wood can be used both outdoors and indoors without finishing, unfinished wood surfaces exposed to the weather change color, are roughened by photodegradation and surface checking,...

Dynamic fracture characterization of a pressure vessel steel

International Nuclear Information System (INIS)

Schmitt, W.; Boehme, W.; Klemm, W.; Memhard, D.; Winkler, S.

1991-01-01

Dynamic events are characterized by time and space-dependent stress and strain fields caused by wave or inertia effect. The dynamic effect at cracks may be originated from the rapid loading rate or impact loading of a structure containing a stationary crack or the time-dependent stress and strain fields of a propagating or arresting crack itself. Dynamic effects complicate the analysis of crack tip stress and strain fields, and usually considerable experimental effort and numerical technique are required. High loading rate influences the deformation and yield behavior and also the fracture toughness of materials. In order to know the propagation and arrest behavior of cracks, a heat of a German reactor pressure vessel steel was investigated, and the dynamic J-resistance curves were evaluated with large three-point bending specimens by impact loading, moreover, the crack propagation energy at large crack extension was determined with wide tension plates. The material tested was a ferritic pressure vessel steel, ASTM A 508 Cl 2. The dynamic J-resistance curves and numerical simulation and fractographic examination, and crack propagation energy are reported. (K.I.)

Wood fuels utilization in Central Europe - the wood fuels consumption and the targets of utilization

International Nuclear Information System (INIS)

Alakangas, E.

1999-01-01

Following subjects are discussed in this presentation: The share of bioenergy of the total energy consumption in EU region; the wood fuels consumption in EU region in 1995; the division of bioenergy utilization (households, wood- based district heating, wood consumption in industry, power generation from wood and residues, biofuels, biogas and sludges); wood fuels consumption in households in EU countries in 1995; wood consumption in France; the additional wood fuel consumption potential in France; Blan bois - wood energy program; French wood energy markets; German wood energy markets; energy consumption in Germany; wood consumption in Bavaria; the wood fuels potential in Bavaria; wood fuels consumption in households in Bavaria; wood fuels consumption for district heating in Bavaria; fuel prices in Bavaria; Environmental regulations in Germany; small boiler markets in Germany; Energy consumption in Austria; small-scale utilization of wood fuels; utilization of wood energy. (Slides, additional information from the author)

Characterization of volatile constituents in commercial oak wood chips.

Science.gov (United States)

Fernández de Simón, Brígida; Muiño, Iria; Cadahía, Estrella

2010-09-08

The volatile composition of the different oak wood pieces (chips of Quercus spp.) that can be found on the market to be used as alternatives to barrels for aging wines, as well as of chips of Quercus pyrenaica which are being introduced, was studied, evaluating the contents of volatile phenols, lactones, furanic compounds, pyranones, phenolic aldehydes, phenolic ketones, and others. In regard to the overall results, the volatile composition of these products varies widely and has not been clearly laid out according to either the oak species or the wood toasting intensity. Taking into account that the different characteristics of alternatives to barrel products are reflected in the wine treated with them and that an oenological profile based on these variables (origin and toasting level) cannot be defined, only an appropriate chemical analysis would reveal the quality of alternative-to-barrel products and allow us to attempt to foresee its effects on the chemical and organoleptic characteristics of the wines treated with them. On the other hand, the Q. pyrenaica alternative products are very similar to those of other species, with some aromatic particularities, such as their high levels of furanic compounds, eugenol, Furaneol, and cis-whiskylactone, and low levels of vanillin.

Wood construction and magnetic characteristics of impregnated type magnetic wood

International Nuclear Information System (INIS)

Oka, Hideo; Hojo, Atsushi; Seki, Kyoushiro; Takashiba, Toshio

2002-01-01

The results of experiments involving the AC and DC magnetic characteristics of impregnated type magnetic wood were studied by taking into consideration the wood construction and fiber direction. The experimental results show that the sufficient amount of impregnated magnetic fluid varies depending on the fiber direction and length, and the grain face of the wood material. The impregnated type magnetic wood sample that is fully impregnated by magnetic fluid has a 60% saturation magnetization compared to the saturation magnetization of magnetic fluid. Samples for which the wood fiber direction was the same as the direction of the magnetic path had a higher magnetization intensity and permeability

Experimental Characterization and Modeling of the Fracturing Behavior of Marcellus Shale

Science.gov (United States)

Jin, C.; Li, W.; Sageman, B. B.; Cusatis, G.

2014-12-01

Adequate knowledge and prediction of mechanical properties of shale are pivotal to the design of hydraulic fractures. The urgent technical challenge of such an endeavor is how to translate the highly heterogeneous nature of shale into a predictive model of the mechanical properties. Our group addressed this challenge by adopting a combined experimental and numerical approach to investigate fracture processes and failure mechanisms of shale.Lattice Discrete Particle Model (LDPM), having shown superior capabilities in predicting qualitative and quantitative behavior of concrete and concrete-like materials, as shown in Fig. 1, has been adopted to simulate mesoscale behavior of shale. The polyhedral cell system defining the geometric attributes of the rock microstructure is built via a 3D tessellation procedure based on X-ray microtomography results of microstructure and grain size distribution of shale specimens. The adopted tessellation procedure makes use of well-established packing algorithms for no-contact spherical particle placement and non-overlapping volume tessellation. The polyhedral particles interact through triangular facets where appropriate measure of stresses and strains are defined. Especially, LDPM is extended to simulate transversely isotropic materials by using orientation-dependent and strain-dependent strength limits coupled with orientation-dependent normal and shear stiffnesses on each facet. Appropriate interface constitutive equations are formulated to simulate all phenomena occurring at a scale that is smaller than the resolution of LDPM system, including microscopic fracture, frictional contact, particle breakage, pore collapse, and distributed damage. Bedding planes and natural joints are characterized by greatly decreased strength limits for facets within that region. To calibrate/validate the LDPM model, microscopic and mesoscopic experiments, including Brazilian tests, uniaxial compression tests, and three point-bending tests, are

Coupled Fracture and Flow in Shale in Hydraulic Fracturing

Science.gov (United States)

Carey, J. W.; Mori, H.; Viswanathan, H.

2014-12-01

Production of hydrocarbon from shale requires creation and maintenance of fracture permeability in an otherwise impermeable shale matrix. In this study, we use a combination of triaxial coreflood experiments and x-ray tomography characterization to investigate the fracture-permeability behavior of Utica shale at in situ reservoir conditions (25-50 oC and 35-120 bars). Initially impermeable shale core was placed between flat anvils (compression) or between split anvils (pure shear) and loaded until failure in the triaxial device. Permeability was monitored continuously during this process. Significant deformation (>1%) was required to generate a transmissive fracture system. Permeability generally peaked at the point of a distinct failure event and then dropped by a factor of 2-6 when the system returned to hydrostatic failure. Permeability was very small in compression experiments (fashion as pressure increased. We also observed that permeability decreased with increasing fluid flow rate indicating that flow did not follow Darcy's Law, possibly due to non-laminar flow conditions, and conformed to Forscheimer's law. The coupled deformation and flow behavior of Utica shale, particularly the large deformation required to initiate flow, indicates the probable importance of activation of existing fractures in hydraulic fracturing and that these fractures can have adequate permeability for the production of hydrocarbon.

Pristine Early Eocene wood buried deeply in kimberlite from northern Canada.

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Alexander P Wolfe

Full Text Available We report exceptional preservation of fossil wood buried deeply in a kimberlite pipe that intruded northwestern Canada's Slave Province 53.3±0.6 million years ago (Ma, revealed during excavation of diamond source rock. The wood originated from forest surrounding the eruption zone and collapsed into the diatreme before resettling in volcaniclastic kimberlite to depths >300 m, where it was mummified in a sterile environment. Anatomy of the unpermineralized wood permits conclusive identification to the genus Metasequoia (Cupressaceae. The wood yields genuine cellulose and occluded amber, both of which have been characterized spectroscopically and isotopically. From cellulose δ(18O and δ(2H measurements, we infer that Early Eocene paleoclimates in the western Canadian subarctic were 12-17°C warmer and four times wetter than present. Canadian kimberlites offer Lagerstätte-quality preservation of wood from a region with limited alternate sources of paleobotanical information.

Wood preservatives and pressure-treated wood: considerations for historic-preservation projects

Science.gov (United States)

Ronald W. Anthony; Stan T. Lebow

2015-01-01

Wood, an abundant resource throughout most of the world, has been used as a building material for thousands of years. Many historic buildings have been built primarily of wood, and masonry and stone buildings generally have wood elements, both structural and architectural. As a biological material, wood is both remarkably complex and yet quite durable if well...

Characterization of wood dust emission from hand-held woodworking machines.

Science.gov (United States)

Keller, F-X; Chata, F

2018-01-01

This article focuses on the prevention of exposure to wood dust when operating electrical hand-held sawing and sanding machines. A laboratory methodology was developed to measure the dust concentration around machines during operating processes. The main objective was to characterize circular saws and sanders, with the aim of classifying the different power tools tested in terms of dust emission (high dust emitter vs. low dust emitter). A test set-up was developed and is described and a measurement methodology was determined for each of the two operations studied. The robustness of the experimental results is discussed and shows good tendencies. The impact of air-flow extraction rate was assessed and the pressure loss of the system for each machine established. For the circular saws, three machines over the nine tested could be classified in the low dust emitter group. Their mean concentration values measured are between 0.64 and 0.98 mg/m 3 for the low dust emitter group and from 2.55 and 4.37 mg/m 3 for the high dust emitter group. From concentration measurements, a machine classification is possible-one for sanding machines and one for sawing machines-and a ratio from 1-7 is obtained when comparing the results. This classification will be helpful when a choice of high performance power tools, in terms of dust emission, must be made by professionals.

CHARACTERIZATION OF IN-SITU STRESS AND PERMEABILITY IN FRACTURED RESERVOIRS

Energy Technology Data Exchange (ETDEWEB)

Daniel R. Burns; M. Nafi Toksoz

2005-02-04

Numerical modeling and field data tests are presented on the Transfer Function/Scattering Index Method for estimating fracture orientation and density in subsurface reservoirs from the ''coda'' or scattered energy in the seismic trace. Azimuthal stacks indicate that scattered energy is enhanced along the fracture strike direction. A transfer function method is used to more effectively indicate fracture orientation. The transfer function method, which involves a comparison of the seismic signature above and below a reservoir interval, effectively eliminates overburden effects and acquisition imprints in the analysis. The transfer function signature is simplified into a scattering index attribute value that gives fracture orientation and spatial variations of the fracture density within a field. The method is applied to two field data sets, a 3-D Ocean Bottom Cable (OBC) seismic data set from an offshore fractured carbonate reservoir in the Adriatic Sea and a 3-D seismic data set from an onshore fractured carbonate field in the Middle East. Scattering index values are computed in both fields at the reservoir level, and the results are compared to borehole breakout data and Formation MicroImager (FMI) logs in nearby wells. In both cases the scattering index results are in very good agreement with the well data. Field data tests and well validation will continue. In the area of technology transfer, we have made presentations of our results to industry groups at MIT technical review meetings, international technical conferences, industry workshops, and numerous exploration and production company visits.

Integrated control of wood destroying basidiomycetes combining Cu-based wood preservatives and Trichoderma spp.

Science.gov (United States)

Ribera, Javier; Fink, Siegfried; Bas, Maria Del Carmen; Schwarze, Francis W M R

2017-01-01

The production of new generation of wood preservatives (without addition of a co-biocide) in combination with an exchange of wood poles on identical sites with high fungal inoculum, has resulted in an increase of premature failures of wood utility poles in the last decades. Wood destroying basidiomycetes inhabiting sites where poles have been installed, have developed resistance against wood preservatives. The objective of the in vitro studies was to identify a Trichoderma spp. with a highly antagonistic potential against wood destroying basidiomycetes that is capable of colonizing Cu-rich environments. For this purpose, the activity of five Trichoderma spp. on Cu-rich medium was evaluated according to its growth and sporulation rates. The influence of the selected Trichoderma spp. on wood colonization and degradation by five wood destroying basidiomycetes was quantitatively analyzed by means of dry weight loss of wood specimens. Furthermore, the preventative effect of the selected Trichoderma spp. in combination with four Cu-based preservatives was also examined by mass loss and histological changes in the wood specimens. Trichoderma harzianum (T-720) was considered the biocontrol agent with higher antagonistic potential to colonize Cu-rich environments (up to 0.1% CuSO4 amended medium). T. harzianum demonstrated significant preventative effect on wood specimens against four wood destroying basidiomycetes. The combined effect of T. harzianum and Cu-based wood preservatives demonstrated that after 9 months incubation with two wood destroying basidiomycetes, wood specimens treated with 3.8 kg m-3 copper-chromium had weight losses between 55-65%, whereas containers previously treated with T. harzianum had significantly lower weight losses (0-25%). Histological studies on one of the wood destroying basidiomycetes revealed typical decomposition of wood cells by brown-rot fungi in Cu-impregnated samples, that were notably absent in wood specimens previously exposed to T

Integrated control of wood destroying basidiomycetes combining Cu-based wood preservatives and Trichoderma spp.

Directory of Open Access Journals (Sweden)

Javier Ribera

Full Text Available The production of new generation of wood preservatives (without addition of a co-biocide in combination with an exchange of wood poles on identical sites with high fungal inoculum, has resulted in an increase of premature failures of wood utility poles in the last decades. Wood destroying basidiomycetes inhabiting sites where poles have been installed, have developed resistance against wood preservatives. The objective of the in vitro studies was to identify a Trichoderma spp. with a highly antagonistic potential against wood destroying basidiomycetes that is capable of colonizing Cu-rich environments. For this purpose, the activity of five Trichoderma spp. on Cu-rich medium was evaluated according to its growth and sporulation rates. The influence of the selected Trichoderma spp. on wood colonization and degradation by five wood destroying basidiomycetes was quantitatively analyzed by means of dry weight loss of wood specimens. Furthermore, the preventative effect of the selected Trichoderma spp. in combination with four Cu-based preservatives was also examined by mass loss and histological changes in the wood specimens. Trichoderma harzianum (T-720 was considered the biocontrol agent with higher antagonistic potential to colonize Cu-rich environments (up to 0.1% CuSO4 amended medium. T. harzianum demonstrated significant preventative effect on wood specimens against four wood destroying basidiomycetes. The combined effect of T. harzianum and Cu-based wood preservatives demonstrated that after 9 months incubation with two wood destroying basidiomycetes, wood specimens treated with 3.8 kg m-3 copper-chromium had weight losses between 55-65%, whereas containers previously treated with T. harzianum had significantly lower weight losses (0-25%. Histological studies on one of the wood destroying basidiomycetes revealed typical decomposition of wood cells by brown-rot fungi in Cu-impregnated samples, that were notably absent in wood specimens

Wood composites

Science.gov (United States)

Lars Berglund; Roger M. Rowell

2005-01-01

A composite can be defined as two or more elements held together by a matrix. By this definition, what we call “solid wood” is a composite. Solid wood is a three-dimensional composite composed of cellulose, hemicelluloses and lignin (with smaller amounts of inorganics and extractives), held together by a lignin matrix. The advantages of developing wood composites are (...

Plasticity of maritime pine (Pinus pinaster) wood-forming tissues during a growing season.

Science.gov (United States)

Paiva, J A P; Garnier-Géré, P H; Rodrigues, J C; Alves, A; Santos, S; Graça, J; Le Provost, G; Chaumeil, G; Da Silva-Perez, D; Bosc, A; Fevereiro, P; Plomion, C

2008-01-01

The seasonal effect is the most significant external source of variation affecting vascular cambial activity and the development of newly divided cells, and hence wood properties. Here, the effect of edapho-climatic conditions on the phenotypic and molecular plasticity of differentiating secondary xylem during a growing season was investigated. Wood-forming tissues of maritime pine (Pinus pinaster) were collected from the beginning to the end of the growing season in 2003. Data from examination of fibre morphology, Fourier-transform infrared spectroscopy (FTIR), analytical pyrolysis, and gas chromatography/mass spectrometry (GC/MS) were combined to characterize the samples. Strong variation was observed in response to changes in edapho-climatic conditions. A genomic approach was used to identify genes differentially expressed during this growing season. Out of 3512 studied genes, 19% showed a significant seasonal effect. These genes were clustered into five distinct groups, the largest two representing genes over-expressed in the early- or late-wood-forming tissues, respectively. The other three clusters were characterized by responses to specific edapho-climatic conditions. This work provides new insights into the plasticity of the molecular machinery involved in wood formation, and reveals candidate genes potentially responsible for the phenotypic differences found between early- and late-wood.

Quantitative Analysis of Graphene Sheet Content in Wood Char Powders during Catalytic Pyrolysis

Institute of Scientific and Technical Information of China (English)

Yan-Jia Liou; Wu-Jang Huang

2013-01-01

The quantitative characterization of the graphene sheet content in carbon-containing materials is arguable and has not yet been developed.The authors report on a feasible method to characterize graphene sheet content quantitatively in pyrolized carbon materials using an X-ray diffraction (XRD) spectrometer.A direct carbonation at 300 ℃ followed by catalytic pyrolysis (heat-treatment temperature was set at 700-1400 ℃)under a vacuum condition was used for turning wood waste into pyrolized wood char powders.The graphene content in the samples was calculated through an analysis of full width at half maximum (FWHM) of the carbon (100) crystal plane at around 42°-43° in XRD.Results showed that the FWHM and the calculated graphene sheet content of pyrolized wood char powders depended on the heat-treatment temperature,and the FWHM of wood char powder with well-developed graphene sheets (100％) was determined to be 5.0.In addition,the trend to 100％ graphene sheet-contained pyrolized carbon powder was obtained at a heattreatment temperature of 2700 ℃.The resistivity of the wood char powder with 100％ graphene sheets was predicted to be 0.01 Ω cm,close to our experimental data of 0.012 and 0.006 Ω cm for commercial graphite and graphene products,respectively.

Fracturing process and effect of fracturing degree on wave velocity of a crystalline rock

Directory of Open Access Journals (Sweden)

Charalampos Saroglou

2017-10-01

Full Text Available The present paper investigates the effect of fracturing degree on P- and S-wave velocities in rock. The deformation of intact brittle rocks under loading conditions is characterized by a microcracking procedure, which occurs due to flaws in their microscopic structure and propagates through the intact rock, leading to shear fracture. This fracturing process is of fundamental significance as it affects the mechanical properties of the rock and hence the wave velocities. In order to determine the fracture mechanism and the effect of fracturing degree, samples were loaded at certain percentages of peak strength and ultrasonic wave velocity was recorded after every test. The fracturing degree was recorded on the outer surface of the sample and quantified by the use of the indices P10 (traces of joints/m, P20 (traces of joints/m2 and P21 (length of fractures/m2. It was concluded that the wave velocity decreases exponentially with increasing fracturing degree. Additionally, the fracturing degree is described adequately with the proposed indices. Finally, other parameters concerning the fracture characteristics, rock type and scale influence were found to contribute to the velocity decay and need to be investigated further.

Bacteria in decomposing wood and their interactions with wood-decay fungi.

Science.gov (United States)

Johnston, Sarah R; Boddy, Lynne; Weightman, Andrew J

2016-11-01

The fungal community within dead wood has received considerable study, but far less attention has been paid to bacteria in the same habitat. Bacteria have long been known to inhabit decomposing wood, but much remains underexplored about their identity and ecology. Bacteria within the dead wood environment must interact with wood-decay fungi, but again, very little is known about the form this takes; there are indications of both antagonistic and beneficial interactions within this fungal microbiome. Fungi are hypothesised to play an important role in shaping bacterial communities in wood, and conversely, bacteria may affect wood-decay fungi in a variety of ways. This minireview considers what is currently known about bacteria in wood and their interactions with fungi, and proposes possible associations based on examples from other habitats. It aims to identify key knowledge gaps and pressing questions for future research. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Comparative study of large scale simulation of underground explosions inalluvium and in fractured granite using stochastic characterization

Science.gov (United States)

Vorobiev, O.; Ezzedine, S. M.; Antoun, T.; Glenn, L.

2014-12-01

This work describes a methodology used for large scale modeling of wave propagation fromunderground explosions conducted at the Nevada Test Site (NTS) in two different geological settings:fractured granitic rock mass and in alluvium deposition. We show that the discrete nature of rockmasses as well as the spatial variability of the fabric of alluvium is very important to understand groundmotions induced by underground explosions. In order to build a credible conceptual model of thesubsurface we integrated the geological, geomechanical and geophysical characterizations conductedduring recent test at the NTS as well as historical data from the characterization during the undergroundnuclear test conducted at the NTS. Because detailed site characterization is limited, expensive and, insome instances, impossible we have numerically investigated the effects of the characterization gaps onthe overall response of the system. We performed several computational studies to identify the keyimportant geologic features specific to fractured media mainly the joints; and those specific foralluvium porous media mainly the spatial variability of geological alluvium facies characterized bytheir variances and their integral scales. We have also explored common key features to both geologicalenvironments such as saturation and topography and assess which characteristics affect the most theground motion in the near-field and in the far-field. Stochastic representation of these features based onthe field characterizations have been implemented in Geodyn and GeodynL hydrocodes. Both codeswere used to guide site characterization efforts in order to provide the essential data to the modelingcommunity. We validate our computational results by comparing the measured and computed groundmotion at various ranges. This work performed under the auspices of the U.S. Department of Energy by Lawrence LivermoreNational Laboratory under Contract DE-AC52-07NA27344.

Structural and optical properties of wood and wood finishes studied using optical coherence tomography: application to an 18th century Italian violin.

Science.gov (United States)

Latour, Gaël; Echard, Jean-Philippe; Soulier, Balthazar; Emond, Isabelle; Vaiedelich, Stéphane; Elias, Mady

2009-11-20

Optical coherence tomography (OCT) is especially attractive for the study of cultural heritage artifacts because it is noninvasive and nondestructive. We have developed an original full-field time-domain OCT system dedicated to the investigation of varnished and painted artifacts: an interferometric Mirau objective allows one to perform the scan without moving the works of art. The axial and transverse high resolution (respectively, 1.5 and 1 microm) are well adapted to the detection of the investigated structures (pigment grains, wood fibers, etc.). The illumination spectrum is in the visible range (centered at 630 nm, 150 nm wide) to potentially allow us to perform spectroscopic OCT on pigment particles. The examination of wood samples coated with a traditional finish, demonstrates the ability of the system to detect particles, characterize layers thickness, and image the three-dimensional wood structures below the varnishes. OCT has finally been applied to study in situ the coated wood surface of an 18th century Italian violin and provides important information for its conservation treatment.

Non_standard Wood

DEFF Research Database (Denmark)

Tamke, Martin

. Using parametric design tools and computer controlled production facilities Copenhagens Centre for IT and Architecture undertook a practice based research into performance based non-standard element design and mass customization techniques. In close cooperation with wood construction software......, but the integration of traditional wood craft techniques. The extensive use of self adjusting, load bearing wood-wood joints contributed to ease in production and assembly of a performance based architecture....

Thermal Properties of Wood-Plastic Composites Prepared from Hemicellulose-extracted Wood Flour

Directory of Open Access Journals (Sweden)

A.A. Enayati

2013-01-01

Full Text Available Hemicellulose of Southern Yellow Pine wood spices was extracted by pressurized hot water at three different temperatures: 140°C, 155°C and 170°C. Compounding with PP (polypropylene was performed by extrusion after preparing wood flour and sieving to determine its mesh size. The ratio of wood to polymer was 50:50 based on oven-dry weight of wood flour. All extraction treatments and control samples were compounded under two sets of conditions, without and with 2% MAPP as coupling agent. Injection molding was used to make tensile test samples (dogbone from the pellets made by extrusion. Thermal properties of wood-plastic composites were studied by TGA and DSC while the thermal stability of pretreated wood flours, PP and MAPP were studied by TGA as well. The greater weight loss of wood materials was an indication that higher treatment temperature increases the extractability of hemicellulose. The removal of hemicellulose by extraction improves thermal stability of wood flour, especially for extraction at 170°C. Wood-plastic composites made from extracted fibers at 170°C showed the highest thermal stability. Coupling agent did not have a significant effect on thermal stability but it improved the degree of crystallinity of the composites.Surface roughness of wood fiber increased after treatment. Extraction of hemicellulose increased the degree of crystallinity but it was not significant except for samples from treated wood flour at 170°C and with MAPP.

Wood Sawdust/Natural Rubber Ecocomposites Cross-Linked by Electron Beam Irradiation

Directory of Open Access Journals (Sweden)

Elena Manaila

2016-06-01

Full Text Available The obtaining and characterization of some polymeric eco-composites based on wood sawdust and natural rubber is presented. The natural rubber was cross-linked using the electron beam irradiation. The irradiation doses were of 75, 150, 300 and 600 kGy and the concentrations of wood sawdust were of 10 and 20 phr, respectively. As a result of wood sawdust adding, the physical and mechanical properties such as hardness, modulus at 100% elongation and tensile strength, showed significant improvements. The presence of wood sawdust fibers has a reinforcing effect on natural rubber, similar or better than of mineral fillers. An increase in the irradiation dose leads to the increasing of cross-link density, which is reflected in the improvement of hardness, modulus at 100% elongation and tensile strength of blends. The cross-linking rates, appreciated using the Flory-Rehner equation, have increased with the amount of wood sawdust in blends and with the irradiation dose. Even if the gel fraction values have varied irregularly with the amount of wood sawdust and irradiation dose it was over 90% for all blends, except for the samples without wood sawdust irradiated with 75 kGy. The water uptake increased with increasing of fiber content and decreased with the irradiation dose.

The principles, procedures and pitfalls in identifying archaeological and historical wood samples.

Science.gov (United States)

Cartwright, Caroline R

2015-07-01

The science of wood anatomy has evolved in recent decades to add archaeological and historical wood to its repertoire of documenting and characterizing modern and fossil woods. The increasing use of online wood anatomy databases and atlases has fostered the adoption of an international consensus regarding terminology, largely through the work of the International Association of Wood Anatomists (IAWA). This review presents an overview for the general reader of the current state of principles and procedures involved in the study of the wood anatomy of archaeological and historical specimens, some of which may be preserved through charring, waterlogging, desiccation or mineral replacement. By means of selected case studies, the review evaluates to what extent varying preservation of wood anatomical characteristics limits the level of identification to taxon. It assesses the role played by increasingly accessible scanning electron microscopes and complex optical microscopes, and whether these, on the one hand, provide exceptional opportunities for high-quality imaging and analysis of difficult samples, but, on the other hand, might be misleading the novice into thinking that advanced technology can be a substitute for specialized botanical training in wood anatomy. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Transition Fracture Toughness Characterization of Eurofer 97 Steel using Pre-Cracked Miniature Multi-notch Bend Bar Specimens

Energy Technology Data Exchange (ETDEWEB)

Chen, Xiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sokolov, Mikhail A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linton, Kory D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Clowers, Logan N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-11-01

In this report, we present the feasibility study of using pre-cracked miniature multi-notch bend bar specimens (M4CVN) with a dimension of 45mm (length) x 3.3mm (width) x 1.65mm (thickness) to characterize the transition fracture toughness of Eurofer97 based on the ASTM E1921 Master Curve method. From literature survey results, we did not find any obvious specimen size effects on the measured fracture toughness of unirradiated Eurofer97. Nonetheless, in order to exclude the specimen size effect on the measured fracture toughness of neutron irradiated Eurofer97, comparison of results obtained from larger size specimens with those from smaller size specimens after neutron irradiation is necessary, which is not practical and can be formidably expensive. However, limited literature results indicate that the transition fracture toughness of Eurofer97 obtained from different specimen sizes and geometries followed the similar irradiation embrittlement trend. We then described the newly designed experimental setup to be used for testing neutron irradiated Eurofer97 pre-cracked M4CVN bend bars in the hot cell. We recently used the same setup for testing neutron irradiated F82H pre-cracked miniature multi-notch bend bars with great success. Considering the similarity in materials, specimen types, and the nature of tests between Eurofer97 and F82H, we believe the newly designed experimental setup can be used successfully in fracture toughness testing of Eurofer97 pre-cracked M4CVN specimens.

Lignin-Retaining Transparent Wood.

Science.gov (United States)

Li, Yuanyuan; Fu, Qiliang; Rojas, Ramiro; Yan, Min; Lawoko, Martin; Berglund, Lars

2017-09-11

Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30 wt % of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80 wt % of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83 %, haze of 75 %, thermal conductivity of 0.23 W mK -1 , and work-tofracture of 1.2 MJ m -3 (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Hydrogeologic characterization of a fractured granitic rock aquifer, Raymond, California

Energy Technology Data Exchange (ETDEWEB)

Cohen, Andrew J.B. [Univ. of California, Berkeley, CA (United States)

1993-10-01

The hydrogeologic properties of a shallow, fractured granitic rock aquifer in the foothills of the Sierra Nevada, California were investigated via the analysis of borehole geophysical logs and pumping tests. The drawdowns produced during these tests are not indicative of any simple conceptual aquifer model, and borehole logs show that the granite is intensely fractured. These observations are suggestive of a complex fracture-flow geometry which is extremely difficult to decipher. However, through the measurement of orientations of individual subsurface fractures from acoustic televiewer logs, and correlation between particular fractures and electrical resistivity and thermal-pulse flowmeter logs, it was found that the aquifer is, in general, comprised of two subhorizontal and nearly parallel zones of unloading fractures. Downhole flowmeter measurements taken in several wells provide further evidence for the inferred dual-layer structure of the aquifer, as well as yield quantitative measures of the contribution of flow from each zone. Analysis of drawdowns in pumped wells reveals that there are zones of relatively high transmissivity immediately around them. It was found that these properties, as well as a nearby zone of lower transmissivity, can account for their observed drawdowns. A numerical model was constructed to test whether these major heterogeneities could also account for the drawdowns in observation wells. This stepwise analysis of both the geophysical and hydrological data resulted in the formulation of a conceptual model of the aquifer which is consistent with observations, and which can account for its behavior when subjected to pumping.

Infrared thermography for wood density estimation

Science.gov (United States)

López, Gamaliel; Basterra, Luis-Alfonso; Acuña, Luis

2018-03-01

Infrared thermography (IRT) is becoming a commonly used technique to non-destructively inspect and evaluate wood structures. Based on the radiation emitted by all objects, this technique enables the remote visualization of the surface temperature without making contact using a thermographic device. The process of transforming radiant energy into temperature depends on many parameters, and interpreting the results is usually complicated. However, some works have analyzed the operation of IRT and expanded its applications, as found in the latest literature. This work analyzes the effect of density on the thermodynamic behavior of timber to be determined by IRT. The cooling of various wood samples has been registered, and a statistical procedure that enables one to quantitatively estimate the density of timber has been designed. This procedure represents a new method to physically characterize this material.

Determining shear modulus of thin wood composite materials using a cantilever beam vibration method

Science.gov (United States)

Cheng Guan; Houjiang Zhang; John F. Hunt; Haicheng Yan

2016-01-01

Shear modulus (G) of thin wood composite materials is one of several important indicators that characterizes mechanical properties. However, there is not an easy method to obtain this value. This study presents the use of a newly developed cantilever beam free vibration test apparatus to detect in-plane G of thin wood composite...

Mechanics of Wood Machining

CERN Document Server

Csanády, Etele

2013-01-01

Wood is one of the most valuable materials for mankind, and since our earliest days wood materials have been widely used. Today we have modern woodworking machine and tools; however, the raw wood materials available are continuously declining. Therefore we are forced to use this precious material more economically, reducing waste wherever possible. This new textbook on the “Mechanics of Wood Machining” combines the quantitative, mathematical analysis of the mechanisms of wood processing with practical recommendations and solutions. Bringing together materials from many sources, the book contains new theoretical and experimental approaches and offers a clear and systematic overview of the theory of wood cutting, thermal loading in wood-cutting tools, dynamic behaviour of tool and work piece, optimum choice of operational parameters and energy consumption, the wear process of the tools, and the general regularities of wood surface roughness. Diagrams are provided for the quick estimation of various process ...

Fracture detection, mapping, and analysis of naturally fractured gas reservoirs using seismic technology. Final report, November 1995

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-10-01

Many basins in the Rocky Mountains contain naturally fractured gas reservoirs. Production from these reservoirs is controlled primarily by the shape, orientation and concentration of the natural fractures. The detection of gas filled fractures prior to drilling can, therefore, greatly benefit the field development of the reservoirs. The objective of this project was to test and verify specific seismic methods to detect and characterize fractures in a naturally fractured reservoir. The Upper Green River tight gas reservoir in the Uinta Basin, Northeast Utah was chosen for the project as a suitable reservoir to test the seismic technologies. Knowledge of the structural and stratigraphic geologic setting, the fracture azimuths, and estimates of the local in-situ stress field, were used to guide the acquisition and processing of approximately ten miles of nine-component seismic reflection data and a nine-component Vertical Seismic Profile (VSP). Three sources (compressional P-wave, inline shear S-wave, and cross-line, shear S-wave) were each recorded by 3-component (3C) geophones, to yield a nine-component data set. Evidence of fractures from cores, borehole image logs, outcrop studies, and production data, were integrated with the geophysical data to develop an understanding of how the seismic data relate to the fracture network, individual well production, and ultimately the preferred flow direction in the reservoir. The multi-disciplinary approach employed in this project is viewed as essential to the overall reservoir characterization, due to the interdependency of the above factors.

Characterizing Fractures Across the Astronaut Corps: Preliminary Findings from Population-Level Analysis

Science.gov (United States)

Rossi, Meredith M.; Charvat, Jacqueline M.; Sibonga, Jean D.; Sieker, Jeremy

2017-01-01

Despite evidence of bone loss during spaceflight and the implementation of countermeasures to mitigate this loss, the subsequent risk of fracture among astronauts is not known. Multiple factors such as age, sex, fracture history, and others may combine to increase fracture risk. The purpose of this study was to describe fractures among the astronaut population and generate questions for future occupational surveillance studies.

Emissions from laboratory combustor tests of manufactured wood products

Energy Technology Data Exchange (ETDEWEB)

Wilkening, R.; Evans, M.; Ragland, K. [Univ. of Wisconsin, Madison, WI (United States); Baker, A. [USDA Forest Products Lab., Madison, WI (United States)

1993-12-31

Manufactured wood products contain wood, wood fiber, and materials added during manufacture of the product. Manufacturing residues and the used products are burned in a furnace or boiler instead of landfilling. Emissions from combustion of these products contain additional compounds from the combustion of non-wood material which have not been adequately characterized to specify the best combustion conditions, emissions control equipment, and disposal procedures. Total hydrocarbons, formaldehyde, higher aldehydes and carbon monoxide emissions from aspen flakeboard and aspen cubes were measured in a 76 mm i.d. by 1.5 m long fixed bed combustor as a function of excess oxygen, and temperature. Emissions of hydrocarbons, aldehydes and CO from flakeboard and from clean aspen were very sensitive to average combustor temperature and excess oxygen. Hydrocarbon and aldehyde emissions below 10 ppM were achieved with 5% excess oxygen and 1,200{degrees}C average temperature for aspen flakeboard and 1,100{degrees}C for clean aspen at a 0.9 s residence time. When the average temperature decreased below these levels, the emissions increased rapidly. For example, at 950{degrees}C and 5% excess oxygen the formaldehyde emissions were over 1,000 ppM. These laboratory tests reinforce the need to carefully control the temperature and excess oxygen in full-scale wood combustors.

Soil-wood interactions

NARCIS (Netherlands)

Wal, van der Annemieke; klein Gunnewiek, Paulien; Boer, de Wietse

2017-01-01

Wood-inhabiting fungi may affect soil fungal communities directly underneath decaying wood via their exploratory hyphae. In addition, differences in wood leachates between decaying tree species may influence soil fungal communities. We determined the composition of fungi in 4-yr old decaying logs

Tracer transport in fractured rocks

International Nuclear Information System (INIS)

Tsang, C.F.; Tsang, Y.W.; Hale, F.V.

1988-07-01

Recent interest in the safety of toxic waste underground disposal and nuclear waste geologic repositories has motivated many studies of tracer transport in fractured media. Fractures occur in most geologic formations and introduce a high degree of heterogeneity. Within each fracture, the aperture is not constant in value but strongly varying. Thus for such media, tracer tends to flow through preferred flowpaths or channels within the fractures. Along each of these channels, the aperture is also strongly varying. A detailed analysis is carried out on a 2D single fracture with variable apertures and the flow through channels is demonstrated. The channels defined this way are not rigidly set pathways for tracer transport, but are the preferred flow paths in the sense of stream-tubes in the potential theory. It is shown that such variable-aperture channels can be characterized by an aperture probability distribution function, and not by the exact deterministic geometric locations. We also demonstrate that the 2D tracer transport in a fracture can be calculated by a model of a system of 1D channels characterized by this distribution function only. Due to the channeling character of tracer transport in fractured rock, random point measurements of tracer breakthrough curves may give results with a wide spread in value due to statistical fluctuations. The present paper suggests that such a wide spread can probably be greatly reduced by making line/areal (or multiple) measurements covering a few spatial correlation lengths. 13 refs., 11 figs., 1 tab

Determination of Fracture System Geometry from Well Testing

International Nuclear Information System (INIS)

Doe, T.W.

1994-01-01

In this paper, the research and development for the description of the hydraulic geometry of fracture networks are discussed. The studies on fracture networks have developed on the premise that the structural geological information on fracture geometries could be used to develop the realistic models of flow. It has been widely recognized that a relatively small portion of natural fracture networks controls a major portion of groundwater flow. The key to efficient network modeling is to identify that portion of networks. It is the main purpose of this paper to discuss the methods for characterizing the hydraulic geometry of fracture flow systems. The methods described in this paper cover three approaches for defining the hydraulic geometry of fracture networks, that is, the determination of conductive fracture frequency in boreholes, the use of transient pressure and flow responses in single holes, and the use of cross hole test to assess connectivity. The information which can be obtained by each test is shown. Flow logging, well test distribution and conductive fracture frequency are discussed. The transient analysis of single hole well test and the cross hole analysis of well test for fracture network geometry are reported. The data taken by various methods together can provide network characterization. (K.I.)

Detection and Characterization of Natural and Induced Fractures for the Development of Enhanced Geothermal Systems

Energy Technology Data Exchange (ETDEWEB)

Toksoz, M. Nafi [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Earth, Atmospheric and Planetary Sciences

2013-04-06

The objective of this 3-year project is to use various geophysical methods for reservoir and fracture characterization. The targeted field is the Cove Fort-Sulphurdale Geothermal Field in Utah operated by ENEL North America (ENA). Our effort has been focused on 1) understanding the regional and local geological settings around the geothermal field; 2) collecting and assembling various geophysical data sets including heat flow, gravity, magnetotelluric (MT) and seismic surface and body wave data; 3) installing the local temporary seismic network around the geothermal site; 4) imaging the regional and local seismic velocity structure around the geothermal field using seismic travel time tomography; and (5) determining the fracture direction using the shear-wave splitting analysis and focal mechanism analysis. Various geophysical data sets indicate that beneath the Cove Fort-Sulphurdale Geothermal Field, there is a strong anomaly of low seismic velocity, low gravity, high heat flow and high electrical conductivity. These suggest that there is a heat source in the crust beneath the geothermal field. The high-temperature body is on average 150 °C – 200 °C hotter than the surrounding rock. The local seismic velocity and attenuation tomography gives a detailed velocity and attenuation model around the geothermal site, which shows that the major geothermal development target is a high velocity body near surface, composed mainly of monzonite. The major fracture direction points to NNE. The detailed velocity model along with the fracture direction will be helpful for guiding the geothermal development in the Cove Fort area.

Wood energy-commercial applications

Science.gov (United States)

Kennel, R. P.

1978-01-01

Wood energy is being widely investigated in many areas of the country because of the many obvious benefits of wood fuel such as the low price per million Btus relative to coal, oil, and gas; the wide availability of noncommercial wood and the proven ability to harvest it; established technology which is reliable and free of pollution; renewable resources; better conservation for harvested land; and the potential for jobs creation. The Southeastern United States has a specific leadership role in wood energy based on its established forest products industry experience and the potential application of wood energy to other industries and institutions. Significant questions about the widespread usage of wood energy are being answered in demonstrations around the country as well as the Southeast in areas of wood storage and bulk handling; high capitalization costs for harvesting and combustion equipment; long term supply and demand contracts; and the economic feasibility of wood energy outside the forest products industry.

The fracture zone project - final report

International Nuclear Information System (INIS)

Andersson, Peter

1993-09-01

This report summarizes the work and the experiences gained during the fracture zone project at the Finnsjoen study site. The project is probably the biggest effort, so far, to characterize a major fracture zone in crystalline bedrock. The project was running between 1984-1990 involving a large number of geological, geohydrological, geochemical, and geomechanical investigation. The methods used for identification and characterization are reviewed and discussed in terms of applicability and possible improvements for future investigations. The discussion is exemplified with results from the investigation within the project. Flow and transport properties of the zone determined from hydraulic tests and tracer tests are discussed. A large number of numerical modelling efforts performed within the fracture zone project, the INTRAVAL project, and the SKB91-study are summarized and reviewed. Finally, occurrence of similar zones and the relevance of major low angle fracture zones in connection to the siting of an underground repository is addressed

Dose in a house built with contaminated wood

International Nuclear Information System (INIS)

Thomassin, A.

2006-01-01

This paper aims to assess the annual effective dose which could be received by a person living in a house built in France with wood from Belarus and contaminated by cesium 137 from Chernobylsk accident fallout. After the context be specified and the potential levels of radioactivity presented, an assessment of the annual effective dose is performed, based on an as realistic as possible scenario. After calculations it appears that the annual effective dose by external exposure potentially received by an inhabitant living in a house build with contaminated wood (pine or birch) at 1,000 Bq/kg is of the order of 1 mSv, due to external exposure to walls. This dose is not negligible, and could even be much more higher if wood from highly contaminated Belarusian areas is used for building houses. Projects of such wooden buildings should be studied with a particular attention to the characterization of the contamination. (N.C.)

Dose in a house built with contaminated wood

Energy Technology Data Exchange (ETDEWEB)

Thomassin, A. [Institut de Radioprotection et de Surete Nucleaire (IRSN), 92 - Fontenay aux Roses (France)

2006-07-01

This paper aims to assess the annual effective dose which could be received by a person living in a house built in France with wood from Belarus and contaminated by cesium 137 from Chernobylsk accident fallout. After the context be specified and the potential levels of radioactivity presented, an assessment of the annual effective dose is performed, based on an as realistic as possible scenario. After calculations it appears that the annual effective dose by external exposure potentially received by an inhabitant living in a house build with contaminated wood (pine or birch) at 1,000 Bq/kg is of the order of 1 mSv, due to external exposure to walls. This dose is not negligible, and could even be much more higher if wood from highly contaminated Belarusian areas is used for building houses. Projects of such wooden buildings should be studied with a particular attention to the characterization of the contamination. (N.C.)

Who's Counting Dead Wood ?

OpenAIRE

Woodall, C. W.; Verkerk, H.; Rondeux, Jacques; Ståhl, G.

2009-01-01

Dead wood in forests is a critical component of biodiversity, carbon and nutrient cycles, stand structure, and fuel loadings. Until recently, very few countries have conducted systematic inventories of dead wood resources across their forest lands. This may be changing as an increasing number of countries implement dead wood inventories. A recent survey looks at the status and attributes of forest dead wood inventories in over 60 countries. About 13 percent of countries inventory dead wood gl...

Stand structure and dead wood characterization in cork forest of Calabria region (southern Italy

Directory of Open Access Journals (Sweden)

Barreca L

2010-07-01

Full Text Available The cork forests are one the most interesting forest ecosystems in the Mediterranean area. Their distribution and ecological characteristics have undergone a significant transformation after the significant changes following the development and establishment of agricultural crops. Currently, only a few stands, which survive in hard to reach places, prove the wide spread distribution of this species was also in the recent past. This study describes the stand structure of some cork forests in Calabria region (southern Italy. In order, to characterize the vertical structure Latham index has been applied, while for the description of the horizontal distribution NBSI group indices has been used. Detailed surveys on dead wood were also conducted determining the occurring volume and its decay stage according to the decay classes system proposed by Hunter. The aim of this study is to provide guidelines for sustainable management of cork forests, improving and promoting the structural complexity and functional efficiency of these forest stands.

Understanding hydraulic fracturing: a multi-scale problem

Science.gov (United States)

Hyman, J. D.; Jiménez-Martínez, J.; Viswanathan, H. S.; Carey, J. W.; Porter, M. L.; Rougier, E.; Karra, S.; Kang, Q.; Frash, L.; Chen, L.; Lei, Z.; O’Malley, D.; Makedonska, N.

2016-01-01

Despite the impact that hydraulic fracturing has had on the energy sector, the physical mechanisms that control its efficiency and environmental impacts remain poorly understood in part because the length scales involved range from nanometres to kilometres. We characterize flow and transport in shale formations across and between these scales using integrated computational, theoretical and experimental efforts/methods. At the field scale, we use discrete fracture network modelling to simulate production of a hydraulically fractured well from a fracture network that is based on the site characterization of a shale gas reservoir. At the core scale, we use triaxial fracture experiments and a finite-discrete element model to study dynamic fracture/crack propagation in low permeability shale. We use lattice Boltzmann pore-scale simulations and microfluidic experiments in both synthetic and shale rock micromodels to study pore-scale flow and transport phenomena, including multi-phase flow and fluids mixing. A mechanistic description and integration of these multiple scales is required for accurate predictions of production and the eventual optimization of hydrocarbon extraction from unconventional reservoirs. Finally, we discuss the potential of CO2 as an alternative working fluid, both in fracturing and re-stimulating activities, beyond its environmental advantages. This article is part of the themed issue ‘Energy and the subsurface’. PMID:27597789

Occurrence patterns of dead wood and wood-dependent lichens in managed boreal forest landscapes

OpenAIRE

Svensson, Måns

2013-01-01

Dead wood is a key resource for biodiversity, on which thousands of forest organisms are dependent. Because of current forest management, there has been a large-scale change in dead wood amounts and qualities, and consequently, many wood-dependent species are threatened. The general aim of this thesis is to increase our understanding of habitat requirements and occurrence patterns of wood-dependent lichens in managed, boreal forest landscapes. We surveyed dead wood and wood-dependent lichens ...

Energy from wood - an overview

International Nuclear Information System (INIS)

Nussbaumer, T.

2000-01-01

The present publication is the introduction to a series of papers on fundamentals and applications of wood energy. It summarizes figures and data of the actual situation of fuel wood utilization in Switzerland and its potential for the future. Further, the advantages of bio-energy are discussed and the possibilities of funding for bio-energy in Switzerland are described. Wood contributes with 2.5% to the total energy demand in Switzerland nowadays. However, the utilization of wood energy can be more than doubled, which is one of the targets of the Swiss energy policy. The supply chains for the different types of fuel wood are described and specifications and prices of log wood, forestry wood chips and wood residues are presented. The main applications of wood energy are residential heating with manually operated wood boilers and stoves, on the one hand, and heat production with automatic wood furnaces in industry and communities, on the other hand. Automatic furnaces have been promoted in the past ten years and hence they contribute nowadays with more than 50% to the energy supply from wood with a further growing share. As an assistance for further information, a list of institutions and addresses in the field of wood energy in Switzerland is given in the paper. (author)

Characterization of structure and development of models to quantify wood potential of an unmanaged Araucaria angustifolia stand

Directory of Open Access Journals (Sweden)

Rafaella De Angeli Curto

2014-12-01

Full Text Available The objective of this study was to characterize of an unmanaged stand of Araucaria angustifolia and to development of models to quantify the wood potential, aiming to support the development of forest management plans in stands with similar conditions. The work was developed into a stand established in 1946, in National Forest of Açungui, in Campo Largo County, Paraná State, Brazil. There was only one thinning in the stand, between 1970 and 1980. From the frequency of individuals in each diametric class, it was observed the condition of stagnation and competition with cohort in the beginning of class distribution. With the application of the probability density function of Weibull-3P, Trorey model, and the 5th polynomial by diameter class, it was possible to confirm the stock estimative of timber volume of the stand. This analysis indicated that the stand presents average annual wood production smaller than the species potential. So it is recommended the thinning to promote growth of remnant trees. With the probability density function of Weibull-3p, that was selected, it is possible to project the diametric distribution of the stand, when analyzed complementarily with growth diameter information, if the stand remains unmanaged. Certainly, the optimum potential of timber production could have been manifested if the stand were managed during the cycle planed.

Construction of hydrophobic wood surfaces by room temperature deposition of rutile (TiO2) nanostructures

Science.gov (United States)

Rongbo Zheng; Mandla A. Tshabalala; Qingyu Li; Hongyan Wang

2015-01-01

A convenient room temperature approach was developed for growing rutile TiO2 hierarchical structures on the wood surface by direct hydrolysis and crystallization of TiCl3 in saturated NaCl aqueous solution.The morphology and the crystal structure of TiO2 coated on the wood surface were characterized...

Preparation and Characterization of Epoxy Resin Cross-Linked with High Wood Pyrolysis Bio-Oil Substitution by Acetone Pretreatment

Directory of Open Access Journals (Sweden)

Yi Liu

2017-03-01

Full Text Available The use of cost effective solvents may be necessary to store wood pyrolysis bio-oil in order to stabilize and control its viscosity, but this part of the production system has not been explored. Conversely, any rise in viscosity during storage, that would occur without a solvent, will add variance to the production system and render it cost ineffective. The purpose of this study was to modify bio-oil with a common solvent and then react the bio-oil with an epoxy for bonding of wood without any loss in properties. The acetone pretreatment of the bio-oil/epoxy mixture was found to improve the cross-linking potential and substitution rate based on its mechanical, chemical, and thermal properties. Specifically, the bio-oil was blended with epoxy resin at weight ratios ranging from 2:1 to 1:5 and were then cured. A higher bio-oil substitution rate was found to lower the shear bond strength of the bio-oil/epoxy resins. However, when an acetone pretreatment was used, it was possible to replace the bio-oil by as much as 50% while satisfying usage requirements. Extraction of the bio-oil/epoxy mixture with four different solvents demonstrated an improvement in cross-linking after acetone pretreatment. ATR-FTIR analysis confirmed that the polymer achieved a higher cross-linked structure. DSC and TGA curves showed improved thermal stability with the addition of the acetone pretreatment. UV-Vis characterization showed that some functional groups of the bio-oil to epoxy system were unreacted. Finally, when the resin mixture was utilized to bond wood, the acetone pretreatment coupled with precise tuning of the bio-oil:epoxy ratio was an effective method to control cross-linking while ensuring acceptable bond strength.

Wood preservative testing

Science.gov (United States)

Rebecca Ibach; Stan T. Lebow

2012-01-01

Most wood species used in commercial and residential construction have little natural biological durability and will suffer from biodeterioration when exposed to moisture. Historically, this problem has been overcome by treating wood for outdoor use with toxic wood preservatives. As societal acceptance of chemical use changes, there is continual pressure to develop and...

Transatlantic wood pellet trade demonstrates telecoupled benefits

Directory of Open Access Journals (Sweden)

Esther S. Parish

2018-03-01

Full Text Available European demand for renewable energy resources has led to rapidly increasing transatlantic exports of wood pellets from the southeastern United States (SE US since 2009. Disagreements have arisen over the global greenhouse gas reductions associated with replacing coal with wood, and groups on both sides of the Atlantic Ocean have raised concerns that increasing biomass exports might negatively affect SE US forests and the ecosystem services they provide. We use the telecoupling framework to test assertions that the intended benefits of the wood pellet trade for Europe might be offset by negative consequences in the SE US. Through a review of current literature and available data sets, we characterize the observed and potential changes in the environmental, social, and economic components of the sending and receiving regions to assess the overall sustainability of this renewable energy system. We conclude that the observed transatlantic wood pellet trade is an example of a mutually beneficial telecoupled system with the potential to provide environmental and socioeconomic benefits in both the SE US and Europe despite some negative effects on the coal industry. We recommend continued monitoring of this telecoupled system to quantify the environmental, social, and economic interactions and effects in the sending, receiving, and spillover systems over time so that evidence-based policy decisions can be made with regard to the sustainability of this renewable energy pathway.

High-Throughput DNA sequencing of ancient wood.

Science.gov (United States)

Wagner, Stefanie; Lagane, Frédéric; Seguin-Orlando, Andaine; Schubert, Mikkel; Leroy, Thibault; Guichoux, Erwan; Chancerel, Emilie; Bech-Hebelstrup, Inger; Bernard, Vincent; Billard, Cyrille; Billaud, Yves; Bolliger, Matthias; Croutsch, Christophe; Čufar, Katarina; Eynaud, Frédérique; Heussner, Karl Uwe; Köninger, Joachim; Langenegger, Fabien; Leroy, Frédéric; Lima, Christine; Martinelli, Nicoletta; Momber, Garry; Billamboz, André; Nelle, Oliver; Palomo, Antoni; Piqué, Raquel; Ramstein, Marianne; Schweichel, Roswitha; Stäuble, Harald; Tegel, Willy; Terradas, Xavier; Verdin, Florence; Plomion, Christophe; Kremer, Antoine; Orlando, Ludovic

2018-03-01

Reconstructing the colonization and demographic dynamics that gave rise to extant forests is essential to forecasts of forest responses to environmental changes. Classical approaches to map how population of trees changed through space and time largely rely on pollen distribution patterns, with only a limited number of studies exploiting DNA molecules preserved in wooden tree archaeological and subfossil remains. Here, we advance such analyses by applying high-throughput (HTS) DNA sequencing to wood archaeological and subfossil material for the first time, using a comprehensive sample of 167 European white oak waterlogged remains spanning a large temporal (from 550 to 9,800 years) and geographical range across Europe. The successful characterization of the endogenous DNA and exogenous microbial DNA of 140 (~83%) samples helped the identification of environmental conditions favouring long-term DNA preservation in wood remains, and started to unveil the first trends in the DNA decay process in wood material. Additionally, the maternally inherited chloroplast haplotypes of 21 samples from three periods of forest human-induced use (Neolithic, Bronze Age and Middle Ages) were found to be consistent with those of modern populations growing in the same geographic areas. Our work paves the way for further studies aiming at using ancient DNA preserved in wood to reconstruct the micro-evolutionary response of trees to climate change and human forest management. © 2018 John Wiley & Sons Ltd.

Wood Dust

Science.gov (United States)

Learn about wood dust, which can raise the risk of cancers of the paranasal sinuses and nasal cavity. High amounts of wood dust are produced in sawmills, and in the furniture-making, cabinet-making, and carpentry industries.

Wood Smoke

Science.gov (United States)

Smoke is made up of a complex mixture of gases and fine, microscopic particles produced when wood and other organic matter burn. The biggest health threat from wood smoke comes from fine particles (also called particulate matter).

Assessment and management of dead-wood habitat

Science.gov (United States)

Hagar, Joan

2007-01-01

; Marcot, 2003). For example, by puncturing bark and fragmenting sapwood, woodpeckers create sites favorable for wood-decaying organisms (Farris et al., 2004), which in turn create habitat for other species and facilitate nutrient cycling. Small mammals that use down wood for cover function in the dispersal of plant seeds and fungal spores (Carey et al., 1999). Resident cavitynesting birds may regulate insect populations by preying on overwintering arthropods (Jackson, 1979; Kroll and Fleet, 1979). These examples illustrate how dead wood not only directly provides habitat for a large number of wildlife species, but also forms the foundation of functional webs that critically influence forest ecosystems (Marcot, 2002; Marcot, 2003). The important and far-reaching implications of management of decaying wood highlight the need for conservation of dead-wood resources in managed forests. Consideration of the key ecological functions of species associated with dead wood can help guide management of dead wood in a framework consistent with the paradigm of ecosystem management (Marcot and Vander Heyden, 2001; Marcot, 2002.) As more information is revealed about the ecological and habitat values of decaying wood, concern has increased over a reduction in the current amounts of dead wood relative to historic levels (Ohmann and Waddell, 2002). Past management practices have tended to severely reduce amounts of dead wood throughout all stages of forest development (Hansen et al., 1991). The large amounts of legacy wood that characterize young post-disturbance forests are not realized in managed stands, because most of the wood volume is removed at harvest for economic and safety reasons. Mid-rotation thinning is used to “salvage” some mortality that might otherwise occur due to suppression, so fewer snags are recruited in mid-seral stages. Harvest rotations of 80 years or less truncate tree size in managed stands, and thus limit the production of large-diameter wood. As a

Cyclic polyalcohols: fingerprints to identify the botanical origin of natural woods used in wine aging.

Science.gov (United States)

Alañón, M Elena; Díaz-Maroto, M Consuelo; Díaz-Maroto, Ignacio J; Vila-Lameiro, Pablo; Pérez-Coello, M Soledad

2011-02-23

Cyclic polyalcohol composition of 80 natural wood samples from different botanical species, with the majority of them used in the oenology industry for aging purposes, has been studied by gas chromatography-mass spectrometry (GC-MS) after its conversion into their trimethylsilyloxime derivatives. Each botanical species showed a different and specific cyclic polyalcohol profile. Oak wood samples were characterized by the richness in deoxyinositols, especially proto-quercitol. Meanwhile, other botanical species showed a very low content of cyclic polyalcohols. The qualitative and quantitative study of cyclic polyalcohols was a useful tool to characterize and differentiate woods of different botanical origin to guarantee the authenticity of chips used in the wine-aging process. Monosaccharide composition was also analyzed, showing some quantitative differences among species, but cyclic polyalcohols were the compounds that revealed the main differentiation power.

Characterizing trabecular bone structure for assessing vertebral fracture risk on volumetric quantitative computed tomography

Science.gov (United States)

Nagarajan, Mahesh B.; Checefsky, Walter A.; Abidin, Anas Z.; Tsai, Halley; Wang, Xixi; Hobbs, Susan K.; Bauer, Jan S.; Baum, Thomas; Wismüller, Axel

2015-03-01

While the proximal femur is preferred for measuring bone mineral density (BMD) in fracture risk estimation, the introduction of volumetric quantitative computed tomography has revealed stronger associations between BMD and spinal fracture status. In this study, we propose to capture properties of trabecular bone structure in spinal vertebrae with advanced second-order statistical features for purposes of fracture risk assessment. For this purpose, axial multi-detector CT (MDCT) images were acquired from 28 spinal vertebrae specimens using a whole-body 256-row CT scanner with a dedicated calibration phantom. A semi-automated method was used to annotate the trabecular compartment in the central vertebral slice with a circular region of interest (ROI) to exclude cortical bone; pixels within were converted to values indicative of BMD. Six second-order statistical features derived from gray-level co-occurrence matrices (GLCM) and the mean BMD within the ROI were then extracted and used in conjunction with a generalized radial basis functions (GRBF) neural network to predict the failure load of the specimens; true failure load was measured through biomechanical testing. Prediction performance was evaluated with a root-mean-square error (RMSE) metric. The best prediction performance was observed with GLCM feature `correlation' (RMSE = 1.02 ± 0.18), which significantly outperformed all other GLCM features (p biomechanical strength prediction in spinal vertebrae can be significantly improved through characterization of trabecular bone structure with GLCM-derived texture features.

Wood thermoplastic composites

Science.gov (United States)

Daniel F. Caulfield; Craig Clemons; Roger M. Rowell

2010-01-01

The wood industry can expand into new sustainable markets with the formation of a new class of composites with the marriage of the wood industry and the plastics industry. The wood component, usually a flour or fiber, is combined with a thermoplastic to form an extrudable, injectable or thermoformable composite that can be used in many non-structural applications....

Status report on experiments and modelling of the cleavage fracture behaviour of F82Hmod using local fracture grid. Task TTMS-005

International Nuclear Information System (INIS)

Riesch-Oppermann, H.; Walter, M.

2001-09-01

Within the European Fusion Technology Programme framework, a fracture mechanics description of the material behaviour in the ductile to brittle transition-regime is developed using local fracture criteria. Based on experimental results using axisymmetrically notched and pre-cracked specimens together with a numerical stress analysis at fracture load, a statistical evaluation of cleavage fracture parameters can be performed along the lines described in various code schemes such as the British Energy R6-Code or the ESIS P6 procedure. The report contains results of the experimental characterization of the deformation and fracture behaviour of the fusion candidate RAFM steel variant F82Hmod, details and background of the numerical procedure for cleavage fracture parameter determination as well as additional statistical inference methods for transferability analysis. Fractographic results give important information about fracture mode and fracture origin sites and their location. Numerical prediction of fracture origin distribution is an important tool for transferability assessment. Future issues comprise constraint effect and ductile damage as well as incorporation of irradiation effects, which are topically addressed. The methodology developed and described in the present report will be applied to characterize material behaviour of future RAFM variants as the EUROFER 97, for which analysis is currently under way. (orig.)

MR imaging of occult fractures of the knee

International Nuclear Information System (INIS)

Mink, J.H.; Deutsch, A.L.

1988-01-01

The authors encountered 65 radiographically occult fractures that they classified into five types. Bone bruises were a result of direct trauma or were associated with ligamentous injury. They were characterized by geographic foci of decreased signal on short repetition time (TR), short echo time (TE) sequences. Stress fractures were linear or globular foci of low signal on short TR, short TE sequences. Osteochondral fractures were displaced or impacted types; the latter were often associated with an anterior cruciate ligament tear. Tibial fractures were minimally displaced, vertically oriented fractures extending into the plateaus. Femoral fractures were Y-shaped, extending across the supracondylar region

NANOCOATING PROCESS FOR TEXTILES APPLICATIONS AND WOOD PROTECTION

Directory of Open Access Journals (Sweden)

NICULESCU Claudia

2014-05-01

Full Text Available This paper presents the research results obtained in ERA NET MANUCOAT project, coordinated by INCDTP in collaboration with the following partners: INCDMNR-IMNR, SC MGM STAR CONSTRUCT SRL –Romania and IRIS-Spain. The objective of the research was to develop and obtain textile and wood surfaces with self-cleaning, photo catalytic, antibacterial and antifungal properties. An innovative method of manufacturing nanoparticles by hydrothermal process in a single step without any further heat treatment and controlled stoichiometry, tested spray coating technology (sputtering were developed. Full characterization of nanostructured powders in terms of chemical, physical, structural, thermal and technological characteristics was performed. The most important features to be considered in the treatment of wood by sputtering in order to deposit thin layers of TiO2 NPs or TiO2/Ag as the humidity should be below 12% and the maximum roughness P150, depending on the species of wood. Future works envisage optimizing the existing sputtering systems for pilot stage, in order to make nanoparticles deposits on large areas of textile and wood. The results of the research are photocatalytic textiles for surgical gowns, operative fields, hospital bed sheets and curtains and drapes for public spaces.

Investigation of translaminar fracture in fibrereinforced composite laminates---applicability of linear elastic fracture mechanics and cohesive-zone model

Science.gov (United States)

Hou, Fang

With the extensive application of fiber-reinforced composite laminates in industry, research on the fracture mechanisms of this type of materials have drawn more and more attentions. A variety of fracture theories and models have been developed. Among them, the linear elastic fracture mechanics (LEFM) and cohesive-zone model (CZM) are two widely-accepted fracture models, which have already shown applicability in the fracture analysis of fiber-reinforced composite laminates. However, there remain challenges which prevent further applications of the two fracture models, such as the experimental measurement of fracture resistance. This dissertation primarily focused on the study of the applicability of LEFM and CZM for the fracture analysis of translaminar fracture in fibre-reinforced composite laminates. The research for each fracture model consisted of two sections: the analytical characterization of crack-tip fields and the experimental measurement of fracture resistance parameters. In the study of LEFM, an experimental investigation based on full-field crack-tip displacement measurements was carried out as a way to characterize the subcritical and steady-state crack advances in translaminar fracture of fiber-reinforced composite laminates. Here, the fiber-reinforced composite laminates were approximated as anisotropic solids. The experimental investigation relied on the LEFM theory with a modification with respect to the material anisotropy. Firstly, the full-field crack-tip displacement fields were measured by Digital Image Correlation (DIC). Then two methods, separately based on the stress intensity approach and the energy approach, were developed to measure the crack-tip field parameters from crack-tip displacement fields. The studied crack-tip field parameters included the stress intensity factor, energy release rate and effective crack length. Moreover, the crack-growth resistance curves (R-curves) were constructed with the measured crack-tip field parameters

Discontinuation of denosumab and associated fracture incidence

DEFF Research Database (Denmark)

Brown, Jacques P; Roux, Christian; Törring, Ove

2012-01-01

associated with transient increases in bone remodeling and declines in bone mineral density (BMD), the effect on fracture risk during treatment cessation is not as well characterized. To understand the fracture incidence between treatment groups after cessation of investigational product, we evaluated...

Antioxidant airway responses following experimental exposure to wood smoke in man

Directory of Open Access Journals (Sweden)

Sehlstedt Maria

2010-08-01

Full Text Available Abstract Background Biomass combustion contributes to the production of ambient particulate matter (PM in rural environments as well as urban settings, but relatively little is known about the health effects of these emissions. The aim of this study was therefore to characterize airway responses in humans exposed to wood smoke PM under controlled conditions. Nineteen healthy volunteers were exposed to both wood smoke, at a particulate matter (PM2.5 concentration of 224 ± 22 μg/m3, and filtered air for three hours with intermittent exercise. The wood smoke was generated employing an experimental set-up with an adjustable wood pellet boiler system under incomplete combustion. Symptoms, lung function, and exhaled NO were measured over exposures, with bronchoscopy performed 24 h post-exposure for characterisation of airway inflammatory and antioxidant responses in airway lavages. Results Glutathione (GSH concentrations were enhanced in bronchoalveolar lavage (BAL after wood smoke exposure vs. air (p = 0.025, together with an increase in upper airway symptoms. Neither lung function, exhaled NO nor systemic nor airway inflammatory parameters in BAL and bronchial mucosal biopsies were significantly affected. Conclusions Exposure of healthy subjects to wood smoke, derived from an experimental wood pellet boiler operating under incomplete combustion conditions with PM emissions dominated by organic matter, caused an increase in mucosal symptoms and GSH in the alveolar respiratory tract lining fluids but no acute airway inflammatory responses. We contend that this response reflects a mobilisation of GSH to the air-lung interface, consistent with a protective adaptation to the investigated wood smoke exposure.

How spectroscopy and microspectroscopy of degraded wood contribute to understand fungal wood decay.

Science.gov (United States)

Fackler, Karin; Schwanninger, Manfred

2012-11-01

Nuclear magnetic resonance, mid and near infrared, and ultra violet (UV) spectra of wood contain information on its chemistry and composition. When solid wood samples are analysed, information on the molecular structure of the lignocellulose complex of wood e.g. crystallinity of polysaccharides and the orientation of the polymers in wood cell walls can also be gained. UV and infrared spectroscopy allow also for spatially resolved spectroscopy, and state-of-the-art mapping and imaging systems have been able to provide local information on wood chemistry and structure at the level of wood cells (with IR) or cell wall layers (with UV). During the last decades, these methods have also proven useful to follow alterations of the composition, chemistry and physics of the substrate wood after fungi had grown on it as well as changes of the interactions between the wood polymers within the lignocellulose complex caused by decay fungi. This review provides an overview on how molecular spectroscopic methods could contribute to understand these degradation processes and were able to characterise and localise fungal wood decay in its various stages starting from the incipient and early ones even if the major share of research focussed on advanced decay. Practical issues such as requirements in terms of sample preparation and sample form and present examples of optimised data analysis will also be addressed to be able to detect and characterise the generally highly variable microbial degradation processes within their highly variable substrate wood.

Screening and characterizing of xylanolytic and xylose-fermenting yeasts isolated from the wood-feeding termite, Reticulitermes chinensis.

Directory of Open Access Journals (Sweden)

Sameh Samir Ali

Full Text Available The effective fermentation of xylose remains an intractable challenge in bioethanol industry. The relevant xylanase enzyme is also in a high demand from industry for several biotechnological applications that inevitably in recent times led to many efforts for screening some novel microorganisms for better xylanase production and fermentation performance. Recently, it seems that wood-feeding termites can truly be considered as highly efficient natural bioreactors. The highly specialized gut systems of such insects are not yet fully realized, particularly, in xylose fermentation and xylanase production to advance industrial bioethanol technology as well as industrial applications of xylanases. A total of 92 strains from 18 yeast species were successfully isolated and identified from the gut of wood-feeding termite, Reticulitermes chinensis. Of these yeasts and strains, seven were identified for new species: Candida gotoi, Candida pseudorhagii, Hamamotoa lignophila, Meyerozyma guilliermondii, Sugiyamaella sp.1, Sugiyamaella sp. 2, and Sugiyamaella sp.3. Based on the phylogenetic and phenotypic characterization, the type strain of C. pseudorhagii sp. nov., which was originally designated strain SSA-1542T, was the most frequently occurred yeast from termite gut samples, showed the highly xylanolytic activity as well as D-xylose fermentation. The highest xylanase activity was recorded as 1.73 and 0.98 U/mL with xylan or D-xylose substrate, respectively, from SSA-1542T. Among xylanase-producing yeasts, four novel species were identified as D-xylose-fermenting yeasts, where the yeast, C. pseudorhagii SSA-1542T, showed the highest ethanol yield (0.31 g/g, ethanol productivity (0.31 g/L·h, and its fermentation efficiency (60.7% in 48 h. Clearly, the symbiotic yeasts isolated from termite guts have demonstrated a competitive capability to produce xylanase and ferment xylose, suggesting that the wood-feeding termite gut is a promising reservoir for novel

Advanced Reservoir Characterization and Evaluation of C02 Gravity Drainage in the Naturally Fractured Sprayberry Trend Area

Energy Technology Data Exchange (ETDEWEB)

David S. Schechter

1998-04-30

The objective is to assess the economic feasibility of CO2 flooding of the naturally fractured Straberry Trend Area in west Texas. Research is being conducted in the extensive characterization of the reservoirs, the experimental studies of crude oil/brine/rock (COBR) interaction in the reservoirs, the analytical and numerical simulation of Spraberry reservoirs, and the experimental investigations on CO2 gravity drainage in Spraberry whole cores.

Fracture characterization in patterned thin films by cross-sectional nanoindentation

International Nuclear Information System (INIS)

Ocana, I.; Molina-Aldareguia, J.M.; Gonzalez, D.; Elizalde, M.R.; Sanchez, J.M.; Martinez-Esnaola, J.M.; Gil Sevillano, J.; Scherban, T..; Pantuso, D.; Sun, B.; Xu, G.; Miner, B.; He, J.; Maiz, J.

2006-01-01

A testing technique based on cross-sectional nanoindentation has been used to assess the mechanical reliability of interconnect structures. A Berkovich indenter was used to initiate fracture in a silicon substrate and cracks propagated through the structure. To better control crack growth and to convert the problem into two dimensions, a trench parallel to the indentation surface was previously machined using a focused ion beam. The crack lengths obtained for different material systems in the interconnect structure correlate well with the fracture energies measured for the same materials in blanket films. Finite element model simulations incorporating cohesive elements have been used to model the fracture processes and to explain the different cracking behaviour observed

Fracture characterization in patterned thin films by cross-sectional nanoindentation

Energy Technology Data Exchange (ETDEWEB)

Ocana, I. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Molina-Aldareguia, J.M. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Gonzalez, D. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Elizalde, M.R. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain)]. E-mail: relizalde@ceit.es; Sanchez, J.M. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Martinez-Esnaola, J.M. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Gil Sevillano, J. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Scherban, T.. E-mail: Tracey_Scherban@Hotmail.com; Pantuso, D. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); Sun, B. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); Xu, G. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); Miner, B. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); He, J. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); Maiz, J. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States)

2006-08-15

A testing technique based on cross-sectional nanoindentation has been used to assess the mechanical reliability of interconnect structures. A Berkovich indenter was used to initiate fracture in a silicon substrate and cracks propagated through the structure. To better control crack growth and to convert the problem into two dimensions, a trench parallel to the indentation surface was previously machined using a focused ion beam. The crack lengths obtained for different material systems in the interconnect structure correlate well with the fracture energies measured for the same materials in blanket films. Finite element model simulations incorporating cohesive elements have been used to model the fracture processes and to explain the different cracking behaviour observed.

Determining wood chip size: image analysis and clustering methods

Directory of Open Access Journals (Sweden)

Paolo Febbi

2013-09-01

Full Text Available One of the standard methods for the determination of the size distribution of wood chips is the oscillating screen method (EN 15149- 1:2010. Recent literature demonstrated how image analysis could return highly accurate measure of the dimensions defined for each individual particle, and could promote a new method depending on the geometrical shape to determine the chip size in a more accurate way. A sample of wood chips (8 litres was sieved through horizontally oscillating sieves, using five different screen hole diameters (3.15, 8, 16, 45, 63 mm; the wood chips were sorted in decreasing size classes and the mass of all fractions was used to determine the size distribution of the particles. Since the chip shape and size influence the sieving results, Wang’s theory, which concerns the geometric forms, was considered. A cluster analysis on the shape descriptors (Fourier descriptors and size descriptors (area, perimeter, Feret diameters, eccentricity was applied to observe the chips distribution. The UPGMA algorithm was applied on Euclidean distance. The obtained dendrogram shows a group separation according with the original three sieving fractions. A comparison has been made between the traditional sieve and clustering results. This preliminary result shows how the image analysis-based method has a high potential for the characterization of wood chip size distribution and could be further investigated. Moreover, this method could be implemented in an online detection machine for chips size characterization. An improvement of the results is expected by using supervised multivariate methods that utilize known class memberships. The main objective of the future activities will be to shift the analysis from a 2-dimensional method to a 3- dimensional acquisition process.

Formaldehyde and acetaldehyde emissions from residential wood combustion in Portugal

Science.gov (United States)

Cerqueira, Mário; Gomes, Luís; Tarelho, Luís; Pio, Casimiro

2013-06-01

A series of experiments were conducted to characterize formaldehyde and acetaldehyde emissions from residential combustion of common wood species growing in Portugal. Five types of wood were investigated: maritime pine (Pinus pinaster), eucalyptus (Eucalyptus globulus), cork oak (Quercus suber), holm oak (Quercus rotundifolia) and pyrenean oak (Quercus pyrenaica). Laboratory experiments were performed with a typical wood stove used for domestic heating in Portugal and operating under realistic home conditions. Aldehydes were sampled from diluted combustion flue gas using silica cartridges coated with 2,4-dinitrophenylhydrazine and analyzed by high performance liquid chromatography with diode array detection. The average formaldehyde to acetaldehyde concentration ratio (molar basis) in the stove flue gas was in the range of 2.1-2.9. Among the tested wood types, pyrenean oak produced the highest emissions for both formaldehyde and acetaldehyde: 1772 ± 649 and 1110 ± 454 mg kg-1 biomass burned (dry basis), respectively. By contrast, maritime pine produced the lowest emissions: 653 ± 151 and 371 ± 162 mg kg-1 biomass (dry basis) burned, respectively. Aldehydes were sampled separately during distinct periods of the holm oak wood combustion cycles. Significant variations in the flue gas concentrations were found, with higher values measured during the devolatilization stage than in the flaming and smoldering stages.

Life cycle environmental impacts of different construction wood waste and wood packaging waste processing methods

OpenAIRE

Manninen, Kaisa; Judl, Jáchym; Myllymaa, Tuuli

2016-01-01

This study compared the life cycle environmental impacts of different wood waste processing methods in three impact categories: climate impact, acidification impacts and eutrophication impacts. The wood waste recovery methods examined were the use of wood waste in terrace boards made out of wood composite which replace impregnated terrace boards, incineration of wood waste in a multi-fuel boiler instead of peat and the use of wood waste in the production of particleboard in either Finland or ...

Mathematical Simulation of Temperature Profiles within Microwave Heated Wood Made for Wood-Based Nano composites

International Nuclear Information System (INIS)

Li, X.; He, X.; Lv, J.; Wu, Y.; Luo, Y.; Chen, H.

2013-01-01

High intensive microwave pretreatment is a new method to modify wood for the fabrication of wood-based nano composites. Based on the physical law on heat transfer, a mathematical model to describe the temperature profiles within wood heated by high intensive microwave was established and simulated in this research. The results showed that the temperature profiles within wood were related to microwave heating methods; The temperature inside wood firstly increased and then gradually decreased along the direction of microwave transmission when the unilateral microwave heating was applied, and the temperature difference along the thickness direction of wood was very significant; The temperature with wood firstly increased and then gradually decreased from the wood surface to interior when the bilateral microwave heating was applied. Compared with the unilateral microwave heating, bilateral microwave heating is a better microwave heating method for the more uniform wood microwave pretreatment.

Mapping the performance of wood-burning stoves by installations worldwide

DEFF Research Database (Denmark)

Luis Teles de Carvalho, Ricardo; Jensen, Ole Michael; Tarelho, Luis A. C.

2016-01-01

environmental health risk. Research stressed the need to increase the performance of conventional interplays between users, stoves and buildings. This scientific review aims to characterize the performance and environmental effects of 9 wood-burning stove categories by installations worldwide...

Many Roles of Wood Adhesives

Science.gov (United States)

Charles R. Frihart

2014-01-01

Although wood bonding is one of the oldest applications of adhesives, going back to early recorded history (1), some aspects of wood bonds are still not fully understood. Most books in the general area of adhesives and adhesion do not cover wood bonding. However, a clearer understanding of wood bonding and wood adhesives can lead to improved products. This is important...

Urban Wood Waste Resource Assessment

Energy Technology Data Exchange (ETDEWEB)

Wiltsee, G.

1998-11-20

This study collected and analyzed data on urban wood waste resources in 30 randomly selected metropolitan areas in the United States. Three major categories wood wastes disposed with, or recovered from, the municipal solid waste stream; industrial wood wastes such as wood scraps and sawdust from pallet recycling, woodworking shops, and lumberyards; and wood in construction/demolition and land clearing debris.

Seismic characteristics of tensile fracture growth induced by hydraulic fracturing

Science.gov (United States)

Eaton, D. W. S.; Van der Baan, M.; Boroumand, N.

2014-12-01

Hydraulic fracturing is a process of injecting high-pressure slurry into a rockmass to enhance its permeability. Variants of this process are used for unconventional oil and gas development, engineered geothermal systems and block-cave mining; similar processes occur within volcanic systems. Opening of hydraulic fractures is well documented by mineback trials and tiltmeter monitoring and is a physical requirement to accommodate the volume of injected fluid. Numerous microseismic monitoring investigations acquired in the audio-frequency band are interpreted to show a prevalence of shear-dominated failure mechanisms surrounding the tensile fracture. Moreover, the radiated seismic energy in the audio-frequency band appears to be a miniscule fraction (<< 1%) of the net injected energy, i.e., the integral of the product of fluid pressure and injection rate. We use a simple penny-shaped crack model as a predictive framework to describe seismic characteristics of tensile opening during hydraulic fracturing. This model provides a useful scaling relation that links seismic moment to effective fluid pressure within the crack. Based on downhole recordings corrected for attenuation, a significant fraction of observed microseismic events are characterized by S/P amplitude ratio < 5. Despite the relatively small aperture of the monitoring arrays, which precludes both full moment-tensor analysis and definitive identification of nodal planes or axes, this ratio provides a strong indication that observed microseismic source mechanisms have a component of tensile failure. In addition, we find some instances of periodic spectral notches that can be explained by an opening/closing failure mechanism, in which fracture propagation outpaces fluid velocity within the crack. Finally, aseismic growth of tensile fractures may be indicative of a scenario in which injected energy is consumed to create new fracture surfaces. Taken together, our observations and modeling provide evidence that

Radioactivity of Wood and Environment

International Nuclear Information System (INIS)

Hus, M.; Kosutic, K.; Lulic, S.

2003-01-01

Nuclear experiments in the atmosphere and nuclear accidents caused global deposition of artificial radionuclides in the soil of Earth's northern hemisphere, the territory of the Republic of Croatia included. Soil contamination by radionuclides resulted in their deposition in plants growing on the contaminated soil as well as in the trees. Large area of the Republic of Croatia is covered with wood, which is exploited in manufacture of industrial wood and for firewood. From approximately 3 million cubic metres of wood exploited annually, nearly one third serves for firewood. In the process of burning a smaller portion of radionuclides deposited in the wood evaporates and goes to atmosphere while a larger portion is retained in the ash. In this paper are presented the results of natural radionuclides 4 0K , 2 32T h and 2 38U as well as of artificial radionuclide 1 37C s content determination in the wood, wood briquette, charcoal and in ash remained after burning the wood, wood briquette and charcoal. The obtained results are discussed from wood radiocontamination aspect and from the aspect of potential environmental radiocontamination by the products from wood burning process. (author)

Wood construction under cold climate

DEFF Research Database (Denmark)

Wang, Xiaodong; Hagman, Olle; Sundqvist, Bror

2014-01-01

As wood constructions increasingly use engineered wood products worldwide, concerns arise about the integrity of the wood and adhesives system. The glueline stability is a crucial issue for engineered wood application, especially under cold climate. In this study, Norway spruce (Picea abies...... affected shear strength of wood joints. As temperature decreased, the shear strength decreased. PUR resin resulted in the strongest shear strength at all temperatures tested. MF resin responded to temperature changes in a similar ways as the PUR resin. The shear strength of wood joints with EPI resins...... specimens need to be tested in further work to more completely present the issue. The EN 301 and EN 302 may need to be specified based on wood species....

European wood-fuel trade

International Nuclear Information System (INIS)

Hillring, B.; Vinterbaeck, J.

2001-01-01

This paper discusses research carried out during the l990s on European wood fuel trade at the Department of Forest Management and Products, SLU, in Sweden. Utilisation of wood-fuels and other biofuels increased very rapidly in some regions during that period. Biofuels are replacing fossil fuels which is an effective way to reduce the future influence of green house gases on the climate. The results indicate a rapid increase in wood-fuel trade in Europe from low levels and with a limited number of countries involved. The chief products traded are wood pellets, wood chips and recycled wood. The main trading countries are, for export, Germany and the Baltic states and, for import, Sweden, Denmark and to some extent the Netherlands. In the future, the increased use of biofuel in European countries is expected to intensify activity in this trade. (orig.)

Controversy. The wood war

International Nuclear Information System (INIS)

James, O.

2010-01-01

The author comments the conflict emerging in France between industries exploiting wood for construction and those exploiting it as a heating material for power generation. The first ones accuse the others to steal their raw material, to pull the prices up, and to destabilize the sector. This conflict takes place notably around sawmill wastes which are used either by wood panel fabricators or by wood pellets producers. Both sectors are claiming they are creating more jobs than the other. The French forest indeed offers good opportunities for both sectors, but other countries which are lacking forest surfaces, are buying wood in France. Several issues are matter of discussion: burning wood seems to go against the reduction of greenhouse gas emissions, subsidies awarded to big heater projects. The situation of the wood sector in Austria, Finland and Poland is briefly presented

Intermetallic alloys: Deformation, mechanical and fracture behaviour

International Nuclear Information System (INIS)

Dogan, B.

1988-01-01

The state of the art in intermetallic alloys development with particular emphasis on deformation, mechanical and fracture behaviour is documented. This review paper is prepared to lay the ground stones for a future work on mechanical property characterization and fracture behaviour of intermetallic alloys at GKSS. (orig.)

Anatomical and chemical properties and density of Coffea arabica L. wood

Directory of Open Access Journals (Sweden)

Marisa Aparecida Pereira

2014-09-01

Full Text Available The state of Minas Gerais is the largest producer of coffee in Brazil and the amount of residue in crops seems adequate to support production of solid wood products of Coffea arabica L., which is currently used for energy purposes or remains in the area. This activity adds insignificant value the coffee products and release CO2, which has harmful effects to the environment. This study was conducted with the aim of characterizing technologically Coffea arabica L. wood to enhance its use in furniture, to characterize its anatomical, chemical and wood basic density. The density showed an average of 0.608g.cm-3. The anatomical analysis showed distinct growth layers, semiporosos vessels with simple perforation plates. The axial parenchyma is apotracheal and diffuse in the aggregate with heterogeneous rays, not laminated and fiber libriformes not septate with bordered pits distinct. The chemical content of extract in hot and cold water were respectively 6.1% and 9.6%. The ash content was found to be 0.68%. Data were comparable to those of mahogany (Swietenia macrophylla and Piptadenia peregrina Benth, (angico-vermelho used for the production of furniture.

Basalt FRP Spike Repairing of Wood Beams

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Luca Righetti

2015-08-01

Full Text Available This article describes aspects within an experimental program aimed at improving the structural performance of cracked solid fir-wood beams repaired with Basalt Fiber Reinforced Polymer (BFRP spikes. Fir wood is characterized by its low density, low compression strength, and high level of defects, and it is likely to distort when dried and tends to fail under tension due to the presence of cracks, knots, or grain deviation. The proposed repair technique consists of the insertion of BFRP spikes into timber beams to restore the continuity of cracked sections. The experimental efforts deal with the evaluation of the bending strength and deformation properties of 24 timber beams. An artificially simulated cracking was produced by cutting the wood beams in half or notching. The obtained results for the repaired beams were compared with those of solid undamaged and damaged beams, and increases of beam capacity, bending strength and of modulus of elasticity, and analysis of failure modes was discussed. For notched beams, the application of the BFRP spikes was able to restore the original bending capacity of undamaged beams, while only a small part of the original capacity was recovered for beams that were cut in half.

Airborne sound transmission loss characteristics of wood-frame construction

Science.gov (United States)

Rudder, F. F., Jr.

1985-03-01

This report summarizes the available data on the airborne sound transmission loss properties of wood-frame construction and evaluates the methods for predicting the airborne sound transmission loss. The first part of the report comprises a summary of sound transmission loss data for wood-frame interior walls and floor-ceiling construction. Data bases describing the sound transmission loss characteristics of other building components, such as windows and doors, are discussed. The second part of the report presents the prediction of the sound transmission loss of wood-frame construction. Appropriate calculation methods are described both for single-panel and for double-panel construction with sound absorption material in the cavity. With available methods, single-panel construction and double-panel construction with the panels connected by studs may be adequately characterized. Technical appendices are included that summarize laboratory measurements, compare measurement with theory, describe details of the prediction methods, and present sound transmission loss data for common building materials.

The Effect of Carbon Nanotubes on the Mechanical Properties of Wood Plastic Composites by Selective Laser Sintering

Directory of Open Access Journals (Sweden)

Yunhe Zhang

2017-12-01

Full Text Available Wood-plastic composites (WPCs made by selective laser sintering (SLS approach of 3D printing offer many advantages over single polymer materials, such as low cost, sustainability, and better sintering accuracy. However, WPCs made via SLS are too weak to have widespread applications. In order to increase the mechanical properties of WPCs, a novel type of WPCs containing 0, 0.05, 0.1 and 0.15 wt % carbon nanotubes (CNT, 14 wt % wood fibers, 86 wt % polyether sulfone (PES was manufactured via SLS. The experimental results showed that the addition of small amount of CNTs can significantly increase the mechanical properties of the wood/PES composite material. The tensile strength, bending strength, and elasticity modulus were 76.3%, 227.9%, and 128.7% higher with 0.1 wt % CNTs than those without CNTs. The mechanical properties of specimens first increased and then decreased with the addition of CNTs. The SEM results of the specimens’ fracture morphology indicate that the preferable bonding interfaces between wood flour grains and PES grains were achieved by adding CNTs to the composites. There are two reasons why the composites possessed superior mechanical properties: CNTs facilitate the laser sintering process of WPCs due to their thermal conductivities, and CNTs directly reinforce WPCs.

Physical Properties of Fractured Porous Media

Science.gov (United States)

Mohammed, T. E.; Schmitt, D. R.

2015-12-01

The effect of fractures on the physical properties of porous media is of considerable interest to oil and gas exploration as well as enhanced geothermal systems and carbon capture and storage. This work represents an attempt to study the effect fractures have on multiple physical properties of rocks. An experimental technique to make simultaneous electric and ultrasonic measurements on cylindrical core plugs is developed. Aluminum end caps are mounted with ultrasonic transducers to transmit pules along the axis of the cylinder while non-polarizing electrodes are mounted on the sides of the core to make complex conductivity measurements perpendicular to the cylinder axis. Electrical measurements are made by applying a sinusoidal voltage across the measurement circuit that consist of a resister and the sample in series. The magnitude and phase of the signal across the sample is recorded relative to the input signal across a range of frequencies. Synthetic rock analogs are constructed using sintered glass beads with fractures imbedded in them. The fracture location, size and orientation are controlled and each fractured specimen has an unfractured counterpart. Porosity, Permeability, electrical conductivity and ultrasonic velocity measurements are conducted on each sample with the complex electrical conductivities recorded at frequencies from 10hz to 1 Mhz. These measurements allow us to examine the changes induced by these mesoscale fractures on the embedding porous medium. Of particular interest is the effect of fracture orientation on electrical conductivity of the rock. Seismic anisotropy caused by fractures is a well understood phenomenon with many rock physics models dedicated to its understanding. The effect of fractures on electrical conductivity is less well understood with electrical anisotropy scarcely investigated in the literature. None the less, using electrical conductivity to characterize fractures can add an extra constraint to characterization based

SIZE SCALING RELATIONSHIPS IN FRACTURE NETWORKS

International Nuclear Information System (INIS)

Wilson, Thomas H.

2000-01-01

The research conducted under DOE grant DE-FG26-98FT40385 provides a detailed assessment of size scaling issues in natural fracture and active fault networks that extend over scales from several tens of kilometers to less than a tenth of a meter. This study incorporates analysis of data obtained from several sources, including: natural fracture patterns photographed in the Appalachian field area, natural fracture patterns presented by other workers in the published literature, patterns of active faulting in Japan mapping at a scale of 1:100,000, and lineament patterns interpreted from satellite-based radar imagery obtained over the Appalachian field area. The complexity of these patterns is always found to vary with scale. In general,but not always, patterns become less complex with scale. This tendency may reverse as can be inferred from the complexity of high-resolution radar images (8 meter pixel size) which are characterized by patterns that are less complex than those observed over smaller areas on the ground surface. Model studies reveal that changes in the complexity of a fracture pattern can be associated with dominant spacings between the fractures comprising the pattern or roughly to the rock areas bounded by fractures of a certain scale. While the results do not offer a magic number (the fractal dimension) to characterize fracture networks at all scales, the modeling and analysis provide results that can be interpreted directly in terms of the physical properties of the natural fracture or active fault complex. These breaks roughly define the size of fracture bounded regions at different scales. The larger more extensive sets of fractures will intersect and enclose regions of a certain size, whereas smaller less extensive sets will do the same--i.e. subdivide the rock into even smaller regions. The interpretation varies depending on the number of sets that are present, but the scale breaks in the logN/logr plots serve as a guide to interpreting the

Manufacture of wood-pellets doubles. Biowatti Oy started a wood pellet plant in Turenki

International Nuclear Information System (INIS)

Rantanen, M.

1999-01-01

Wood pellets have many advantages compared to other fuels. It is longest processed biofuel with favorable energy content. It is simple to use, transport and store. Heating with wood pellets is cheaper than with light fuel oil, and approximately as cheap as utilization of heavy fuel oil, about 110 FIM/MWh. The taxable price of wood pellets is about 550 FIM/t. Stokers and American iron stoves are equally suitable for combustion of wood pellets. Chip fueled stokers are preferred in Finland, but they are also suitable for the combustion of wood pellets. Wood pellets is an environmentally friendly product, because it does not increase the CO 2 load in the atmosphere, and its sulfur and soot emissions are relatively small. The wood pelletizing plant of Biowatti Oy in Turenki was started in an old sugar mill. The Turenki sugar mill was chosen because the technology of the closed sugar factory was suitable for production of wood pellets nearly as such, and required only by slight modifications. A press, designed for briquetting of sugar beat clippings makes the pellets. The Turenki mill will double the volume of wood pellet manufacture in Finland during the next few years. At the start the annual wood pellet production will be 20 000 tons, but the environmental permit allows the production to be increased to 70 000 tons. At first the mill uses planing machine chips as a raw material in the production. It is the most suitable raw material, because it is already dry (moisture content 8-10%), and all it needs is milling and pelletizing. Another possible raw material is sawdust, which moisture content is higher than with planing machine chips. Most of the wood pellets produced are exported e.g. to Sweden, Denmark and Middle Europe. In Sweden there are over 10 000 single-family houses using wood pellets. Biowatti's largest customer is a power plant located in Stockholm, which combusts annually about 200 000 tons of wood pellets

Reliable and non-destructive positioning of larvae of wood-destroying beetles in wood

International Nuclear Information System (INIS)

Kerner, G.; Thiele, H.; Unger, W.

1980-01-01

Living larvae of wood-destroying insects (house longhorn beetle, deathwatch) can be determined in wood by both X-ray technique and vibration measurements. For such examinations convenient commercial devices were used and tested under laboratory conditions. The methods complement each other and lead to a rationalization of the tests of wood preservatives against wood-destroying insects. It seems to be promising to apply the test methods also to timber already used for building

Characterization of fracture reservoirs using static and dynamic data: From sonic and 3D seismic to permeability distribution. Annual report, March 1, 1996--February 28, 1997

Energy Technology Data Exchange (ETDEWEB)

Parra, J.O.; Collier, H.A.; Owen, T.E. [and others

1997-06-01

In low porosity, low permeability zones, natural fractures are the primary source of permeability which affect both production and injection of fluids. The open fractures do not contribute much to porosity, but they provide an increased drainage network to any porosity. They also may connect the borehole to remote zones of better reservoir characteristics. An important approach to characterizing the fracture orientation and fracture permeability of reservoir formations is one based on the effects of such conditions on the propagation of acoustic and seismic waves in the rock. The project is a study directed toward the evaluation of acoustic logging and 3D-seismic measurement techniques as well as fluid flow and transport methods for mapping permeability anisotropy and other petrophysical parameters for the understanding of the reservoir fracture systems and associated fluid dynamics. The principal application of these measurement techniques and methods is to identify and investigate the propagation characteristics of acoustic and seismic waves in the Twin Creek hydrocarbon reservoir owned by Union Pacific Resources (UPR) and to characterize the fracture permeability distribution using production data. This site is located in the overthrust area of Utah and Wyoming. UPR drilled six horizontal wells, and presently UPR has two rigs running with many established drill hole locations. In addition, there are numerous vertical wells that exist in the area as well as 3D seismic surveys. Each horizontal well contains full FMS logs and MWD logs, gamma logs, etc.

Process for carbonizing coal, shale, wood, etc

Energy Technology Data Exchange (ETDEWEB)

Matthaei, K

1924-05-08

A process for carbonization of coal, shale, and wood, for recovering low temperature tar and other products in a rotary retort is described. The material to be carbonized is brought directly in contact with the heating medium, that is characterized in that the heating medium streams through the retort crosswise to the longitudinal axis. The temperature of this medium in the single retort segments can be regulated.

Fracture risk in hepatitis C virus infected persons

DEFF Research Database (Denmark)

Hansen, Ann-Brit Eg; Omland, Lars Haukali; Krarup, Henrik

2014-01-01

BACKGROUND & AIMS: The association between Hepatitis C virus (HCV)-infection and fracture risk is not well characterized. We compared fracture risk between HCV-seropositive (HCV-exposed) patients and the general population and between patients with cleared and chronic HCV-infection. METHODS...

Request for wood samples

NARCIS (Netherlands)

NN,

1977-01-01

In recent years the wood collection at the Rijksherbarium was greatly expanded following a renewed interest in wood anatomy as an aid for solving classification problems. Staff members of the Rijksherbarium added to the collection by taking interesting wood samples with them from their expeditions

Characterization of residues from thermal treatment of treated wood and extraction of Cu, Cr, As and Zn

DEFF Research Database (Denmark)

Ottosen, Lisbeth M.; Pedersen, Anne Juul; Christensen, Iben Vernegren

2005-01-01

, that the charcoal contained a high concentration of Zn, probably from paint. Chemical extraction experiments in HNO were conducted with the charcoal and it was found that the order of extraction (in percentage) was Zn > Cu > As > Cr. A SEM/EDX investigation of the mixed ash from combustion showed the presence...... a matter to cope with when methods to avoid As emission are implemented: the residues with increased concentrations of Cu, Cr and As. In the present paper two different residues after thermal treatment are characterized: a mixed bottom and fly ash from combustion of CCA impregnated wood, and a charcoal...... form in a small layer on the surface of some matrix particles indicating condensation of volatile Cu species. Chemical extraction with inorganic acids showed the order of percentages mobilized as: As > Cu > Cr....

RIMAPS characterization of a surface in the variable aperture fracture model and determination of the main paths for water flow

International Nuclear Information System (INIS)

Fuentes, Nestor O.

2003-01-01

To understand the real incidence of fracture geometry in the unsteady behavior of flowing water channels, the RIMAPS (Rotated Image with Maximum Average Power Spectrum) technique is used to determine the main directions of these channels. This new characterization technique works on digitized images obtained from the surfaces under study. The present work presents the results of a comparison between the flow directions predicted by RIMAPS and the real channels directions observed in a laboratory experiment. A perfect accordance was verified between the directions obtained in both cases. It can be concluded from these results that geometrical characteristics of a fracture surface determine the main path directions for water flow. (author)

Face/core interface fracture characterization of mixed mode bending sandwich specimens

DEFF Research Database (Denmark)

Quispitupa, Amilcar; Berggreen, Christian; Carlsson, L.A.

2011-01-01

and PVC H45, H100 and H250 foam core materials were evaluated. A methodology to perform precracking on fracture specimens in order to achieve a sharp and representative crack front is outlined. The mixed mode loading was controlled in the mixed mode bending (MMB) test rig by changing the loading......Debonding of the core from the face sheets is a critical failure mode in sandwich structures. This paper presents an experimental study on face/core debond fracture of foam core sandwich specimens under a wide range of mixed mode loading conditions. Sandwich beams with E‐glass fibre face sheets...... application point (lever arm distance). Finite element analysis was performed to determine the mode‐mixity at the crack tip. The results showed that the face/core interface fracture toughness increased with increased mode II loading. Post failure analysis of the fractured specimens revealed that the crack...

Editorial: Spatial arrangement of faults and opening-mode fractures

Science.gov (United States)

Laubach, Stephen E.; Lamarche, Juliette; Gauthier, Bertand D. M.; Dunne, William M.

2018-03-01

This issue of the Journal of Structural Geology titled Spatial arrangement of faults and opening-mode fractures explores a fundamental characteristic of fault and fracture arrays. The pattern of fault and opening-mode fracture positions in space defines structural heterogeneity and anisotropy in a rock volume, governs how faults and fractures affect fluid flow, and impacts our understanding of the initiation, propagation and interactions during the formation of fracture patterns. This special issue highlights recent progress with respect to characterizing and understanding the spatial arrangements of fault and fracture patterns, providing examples over a wide range of scales and structural settings.

Fracture toughness master curve characterization of Linde 1092 weld metal for Beaver valley 1 reactor

International Nuclear Information System (INIS)

Lee, Bong Sang; Yang, Won Jon; Hong, Jun Hwa

2000-12-01

This report summarizes the test results obtained from the Korean contribution to the integrity assessment of low toughness Beaver Valley reactor vessel by characterizing the fracture toughness of Linde 1092 (No. 305414) weld metal. 10 PCVN specimens and 10 1T-CT specimens were tested in accordance with the ASTM E 1921-97 standard, 'Standard test method for determination of reference temperature, T o , for ferritic steels in the transition range'. This results can also be useful for assessment of Linde 80 low toughness welds of Kori-1

Fracture toughness master curve characterization of Linde 1092 weld metal for Beaver valley 1 reactor

Energy Technology Data Exchange (ETDEWEB)

Lee, Bong Sang; Yang, Won Jon; Hong, Jun Hwa

2000-12-01

This report summarizes the test results obtained from the Korean contribution to the integrity assessment of low toughness Beaver Valley reactor vessel by characterizing the fracture toughness of Linde 1092 (No. 305414) weld metal. 10 PCVN specimens and 10 1T-CT specimens were tested in accordance with the ASTM E 1921-97 standard, 'Standard test method for determination of reference temperature, T{sub o}, for ferritic steels in the transition range'. This results can also be useful for assessment of Linde 80 low toughness welds of Kori-1.

Visualization and Hierarchical Analysis of Flow in Discrete Fracture Network Models

Science.gov (United States)

Aldrich, G. A.; Gable, C. W.; Painter, S. L.; Makedonska, N.; Hamann, B.; Woodring, J.

2013-12-01

Flow and transport in low permeability fractured rock is primary in interconnected fracture networks. Prediction and characterization of flow and transport in fractured rock has important implications in underground repositories for hazardous materials (eg. nuclear and chemical waste), contaminant migration and remediation, groundwater resource management, and hydrocarbon extraction. We have developed methods to explicitly model flow in discrete fracture networks and track flow paths using passive particle tracking algorithms. Visualization and analysis of particle trajectory through the fracture network is important to understanding fracture connectivity, flow patterns, potential contaminant pathways and fast paths through the network. However, occlusion due to the large number of highly tessellated and intersecting fracture polygons preclude the effective use of traditional visualization methods. We would also like quantitative analysis methods to characterize the trajectory of a large number of particle paths. We have solved these problems by defining a hierarchal flow network representing the topology of particle flow through the fracture network. This approach allows us to analyses the flow and the dynamics of the system as a whole. We are able to easily query the flow network, and use paint-and-link style framework to filter the fracture geometry and particle traces based on the flow analytics. This allows us to greatly reduce occlusion while emphasizing salient features such as the principal transport pathways. Examples are shown that demonstrate the methodology and highlight how use of this new method allows quantitative analysis and characterization of flow and transport in a number of representative fracture networks.

Measurement of Solute Diffusion Behavior in Fractured Waste Glass Media

International Nuclear Information System (INIS)

Saripalli, Kanaka P.; Lindberg, Michael J.; Meyer, Philip D.

2008-01-01

Determination of aqueous phase diffusion coefficients of solutes through fractured media is essential for understanding and modeling contaminants transport at many hazardous waste disposal sites. No methods for earlier measurements are available for the characterization of diffusion in fractured glass blocks. We report here the use of time-lag diffusion experimental method to assess the diffusion behavior of three different solutes (Cs, Sr and Pentafluoro Benzoic Acid or PFBA) in fractured, immobilized low activity waste (ILAW) glass forms. A fractured media time-lag diffusion experimental apparatus that allows the measurement of diffusion coefficients has been designed and built for this purpose. Use of time-lag diffusion method, a considerably easier experimental method than the other available methods, was not previously demonstrated for measuring diffusion in any fractured media. Hydraulic conductivity, porosity and diffusion coefficients of a solute were experimentally measured in fractured glass blocks using this method for the first time. Results agree with the range of properties reported for similar rock media earlier, indicating that the time-lag experimental method can effectively characterize the diffusion coefficients of fractured ILAW glass media

Addresing environmental challenges to shale gas and hydraulic fracturing

Energy Technology Data Exchange (ETDEWEB)

Vadillo Fernandez, L.; Rodriguez Gomez, V.; Fernadez Naranjo, F.J.

2016-07-01

This article reviews the main issues of unconventional gas extracted by hydraulic fracturing techniques. Topics such as technology, fracturing stages, flowback characterization and alternatives of disposal and reuse, water consumption, physicochemical features of the geological formations, development of the fractures performed by hydraulic fracturing, well flow decline, land use and occupation and induced seismicity are presented, as well as the scientific debate: the potential steps of methane gas and groundwater contamination. (Author)

Wood fuel and the environment

International Nuclear Information System (INIS)

Foster, C.A.

1992-01-01

The purpose of this paper is to try and demonstrate the role that the use of Wood as a Fuel can play in our environment. The term ''Wood Fuel'', for the purposes of these proceedings, refers to the use of wood obtained from the forest or the farm. It does not refer to waste wood from for example buildings. The role of wood fuel in the environment can be assessed at many different levels. In this paper three different scales of ''Environment'' and the role of wood fuel in each, will be considered. These three scales are namely the global environment, the local environment, and the National (community) environment. (Author)

Pathogenesis of osteoporotic hip fractures.

Science.gov (United States)

McClung, Michael R

2003-01-01

Osteoporosis is characterized late in the course of the disease by an increased risk of fracture, particularly in the elderly. It occurs in both sexes, affecting approximately 8 million women and 2 million men aged > or = 50 years (1). While low bone density is a predictor of fractures, it is not the only determinant of fracture risk. Other factors include advanced age, altered bone quality, a personal or family history of falls, frailty, poor eyesight, debilitating diseases, and high bone turnover. A diet with sufficient calcium and vitamin D is important to minimize bone loss and, along with regular exercise, to maintain muscle strength. Bisphosphonates have been shown to reduce the risk of hip fracture. For elderly patients, the use of hip protectors may be used as a treatment of last resort. Regardless of the age of the patient, individual patient risk factors must be considered to target appropriate treatment and prevent fracture.

Onset of density-driven instabilities in fractured aquifers

Science.gov (United States)

Jafari Raad, Seyed Mostafa; Hassanzadeh, Hassan

2018-04-01

Linear stability analysis is conducted to study the onset of density-driven convection involved in solubility trapping of C O2 in fractured aquifers. The effect of physical properties of a fracture network on the stability of a diffusive boundary layer in a saturated fractured porous media is investigated using the dual porosity concept. Linear stability analysis results show that both fracture interporosity flow and fracture storativity play an important role in the stability behavior of the system. It is shown that a diffusive boundary layer under the gravity field in fractured porous media with lower fracture storativity and/or higher fracture interporosity flow coefficient is more stable. We present scaling relations for the onset of convective instability in fractured aquifers with single and variable matrix block size distribution. These findings improve our understanding of density-driven flow in fractured aquifers and are important in the estimation of potential storage capacity, risk assessment, and storage site characterization and screening.

High-resolution reconstruction of Arctic paleoclimate derived from 53 million year old kimberlite-hosted Metasequoia wood

Science.gov (United States)

Walker, J. J.; Halfar, J.; Schulze, D.; Gedalof, Z.; Moore, G. W. K.

2009-04-01

The recovery of exceptionally well preserved Eocene wood from kimberlite pipes in the Lac de Gras region of the Northwest Territories, Canada, has allowed for the characterization of the local temperature and hydrologic patterns on an annual scale for this arctic ecosystem (present day latitude: 64 deg N). Wood fragments of ancient Metasequoia sp. trees mixed into the crater facies during kimberlite emplacement were recovered from the Ekati and Diavik diamond mines. Wood recovered from the Ekati "Panda" pipe, which has been dated using Rb-Sr age determination at 53.3 +/- 0.6 million years, is unique in that it exhibits extremely low vitrinite reflectance values, comparable to that of modern near-surface peats. The implication is that the wood has undergone minimal thermal or compressional alteration, thus preserving the geochemical signatures originally formed during growth. Ring width measurements representing over 100 years of climate data show congruence between multiple samples, thus enabling the development of a floating master chronology. Patterns contained in this chronology are of particular interest as the early Eocene was characterized by a period of unusual warming that has been compared to modern day climate change. Wood cellulose does not exchange atoms with its surroundings after formation, making it an ideal candidate for stable isotope analysis once it has been separated from associated whole-wood components. A robotic micromilling device was used to collect whole wood samples of latewood from annual tree rings. The α-cellulose in the samples will be isolated and analyzed for δ13C and δ18O, generating a 34-year floating chronology that can be used to reconstruct decadal scale temperature and humidity patterns. Successful application of this technique suggests that a longer Eocene chronology, using additional wood samples recovered from the Panda pipe as well as samples from neighbouring pipes in the Lac de Gras region, can be developed.

Wood-plastic combination

International Nuclear Information System (INIS)

Schaudy, R.

1978-02-01

A review on wood-plastic combinations is given including the production (wood and plastic component, radiation hardening, curing), the obtained properties, present applications and prospects for the future of these materials. (author)

Fracture size and transmissivity correlations: Implications for transport simulations in sparse three-dimensional discrete fracture networks following a truncated power law distribution of fracture size

Science.gov (United States)

Hyman, J.; Aldrich, G. A.; Viswanathan, H. S.; Makedonska, N.; Karra, S.

2016-12-01

We characterize how different fracture size-transmissivity relationships influence flow and transport simulations through sparse three-dimensional discrete fracture networks. Although it is generally accepted that there is a positive correlation between a fracture's size and its transmissivity/aperture, the functional form of that relationship remains a matter of debate. Relationships that assume perfect correlation, semi-correlation, and non-correlation between the two have been proposed. To study the impact that adopting one of these relationships has on transport properties, we generate multiple sparse fracture networks composed of circular fractures whose radii follow a truncated power law distribution. The distribution of transmissivities are selected so that the mean transmissivity of the fracture networks are the same and the distributions of aperture and transmissivity in models that include a stochastic term are also the same.We observe that adopting a correlation between a fracture size and its transmissivity leads to earlier breakthrough times and higher effective permeability when compared to networks where no correlation is used. While fracture network geometry plays the principal role in determining where transport occurs within the network, the relationship between size and transmissivity controls the flow speed. These observations indicate DFN modelers should be aware that breakthrough times and effective permeabilities can be strongly influenced by such a relationship in addition to fracture and network statistics.

Vibrational modes of hydraulic fractures: Inference of fracture geometry from resonant frequencies and attenuation

Science.gov (United States)

Lipovsky, Bradley P.; Dunham, Eric M.

2015-02-01

Oscillatory seismic signals arising from resonant vibrations of hydraulic fractures are observed in many geologic systems, including volcanoes, glaciers and ice sheets, and hydrocarbon and geothermal reservoirs. To better quantify the physical dimensions of fluid-filled cracks and properties of the fluids within them, we study wave motion along a thin hydraulic fracture waveguide. We present a linearized analysis, valid at wavelengths greater than the fracture aperture, that accounts for quasi-static elastic deformation of the fracture walls, as well as fluid viscosity, inertia, and compressibility. In the long-wavelength limit, anomalously dispersed guided waves known as crack or Krauklis waves propagate with restoring force from fracture wall elasticity. At shorter wavelengths, the waves become sound waves within the fluid channel. Wave attenuation in our model is due to fluid viscosity, rather than seismic radiation from crack tips or fracture wall roughness. We characterize viscous damping at both low frequencies, where the flow is always fully developed, and at high frequencies, where the flow has a nearly constant velocity profile away from viscous boundary layers near the fracture walls. Most observable seismic signals from resonating fractures likely arise in the boundary layer crack wave limit, where fluid-solid coupling is pronounced and attenuation is minimal. We present a method to estimate the aperture and length of a resonating hydraulic fracture using both the seismically observed quality factor and characteristic frequency. Finally, we develop scaling relations between seismic moment and characteristic frequency that might be useful when interpreting the statistics of hydraulic fracture events.

Colorimetric measurements as control elements in wood conservation status

Directory of Open Access Journals (Sweden)

Ovidia Soto-Martín

2014-01-01

Full Text Available This paper is a methodological proposal for the study of altarpieces on wooden supports. The process was implemented to study the altarpiece of San Antonio de Padua in Garachico, Tenerife. For this, we conducted a review of key aspects appropriate to the discipline of wood identification carried out by macroscopic examination and for the characterization of the status of deterioration by colorimetric analysis. For the evaluation of the wood conservation status, the samples were subjected for the first time to colorimetric measurement. As a result we have created an online database to provide information for conservation professionals permitting them to design a proposal for preventive conservation and intervention individually for each object.

Economy of wood supply

International Nuclear Information System (INIS)

Imponen, V.

1993-01-01

Research and development of wood fuels production was vigorous in the beginning of the 1980's. Techniques and working methods used in combined harvesting and transportation of energy and merchantable wood were developed in addition to separate energy wood delivery. After a ten year silent period the research on this field was started again. At present the underutilization of forest supplies and the environmental effects of energy production based on fossil fuels caused the rebeginning of the research. One alternative for reduction of the price of wood fuels at the utilization site is the integration of energy and merchantable wood deliveries together. Hence the harvesting and transportation devices can be operated effectively, and the organizational costs are decreased as well. The wood delivery costs consist of the stumpage price, the harvesting and transportation costs, and of general expenses. The stumpage price form the largest cost category (over 50 %) of the industrial merchantable wood delivery, and the harvesting and transportation costs in the case of thinningwood delivery. Forest transportation is the largest part of the delivery costs of logging residues. The general expenses, consisting of the management costs and the interest costs of the capital bound to the storages, form a remarkable cost category in delivery of low-rank wood for energy or conversion purposes. The costs caused by the harvesting of thinningwood, the logging residues, chipping and crushing, the lorry transportation are reviewed in this presentation

An Analysis of the U.S. Wood Products Import Sector: Prospects for Tropical Wood Products Exporters

Directory of Open Access Journals (Sweden)

W.A.R.T.W. Bandara

2012-10-01

Full Text Available The U.S. has dramatically altered its wood product imports and exports during the past few years,and at present, it is the second largest wood product importer in the world. Hence, an understanding ofmarket structures, factors in selecting foreign suppliers, and the emphasis placed on environmentalissues/certification are critical to understand from the perspective of wood products importers in the U.S.This study provides an analysis of the U.S. wood products import sector with special emphasis on currentand future opportunities for tropical wood products exporters to the U.S. market.In this study, 158 wood products importers in the U.S. were surveyed using a mailingquestionnaire. The adjusted response rate was 40.6 percent. Results indicated that most of the respondentswere small to medium scale firms, but major importers of wood products. According to respondents,wood products to the U.S. mainly come from Brazil, Chile, and China. From the importers’ perspective,Brazilian wood products ranked first for its quality followed by wood products from Chile and Finland.Product quality, long term customer relationships, on-time delivery of orders, fair prices, and supplierreputation were the factors deemed important in selecting overseas suppliers. Majority of respondentswere importing certified wood products. FSC, SFI, and ISO 14000 were the mostly accepted certificationprograms. However, certification was not a major factor in foreign supplier selection criteria. Whenconsidered the U.S. wood products importers’ tendency to diversify their products and species imported,attractive opportunities exist for wood products suppliers from tropical countries.

Wood's lamp examination

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/003386.htm Wood lamp examination To use the sharing features on this page, please enable JavaScript. A Wood lamp examination is a test that uses ultraviolet ( ...

In situ polymerized wood polymer composite: effect of additives and nanoclay on the thermal, mechanical properties

Energy Technology Data Exchange (ETDEWEB)

Devi, Rashmi R; Maji, Tarun K., E-mail: tkm@tezu.ernet.in [Department of Chemical Sciences, Tezpur University, Assam, (India)

2013-11-01

This study concerns the preparation and characterization of wood polymer nanocomposites based on impregnation of styrene acrylonitrile co-polymer-nanoclay intercalating system in presence of glycidyl methacrylate (GMA), a cross linking agent, and vinyl trichloro silane (VTCS) as additives into Simul (Bombex ceiba, L.), a soft wood. The effect of nanoclay and VTCS on the properties of the resultant wood polymer nanocomposites (WPNC) has been evaluated. FTIR spectroscopy shows the interaction among wood, polymers, GMA, nanoclay and VTCS. The penetration of polymer and nanoclay into the wood cell wall is supported by SEM study. The distribution of nanoclay in the SAN polymer matrix present within the wood cell wall has been evidenced by TEM study. TGA results show an improvement in the thermostability of the resultant composites. The inclusion of VTCS enhances the self extinguishing behaviour of the WPNC as revealed by limiting oxygen index (LOI) test. Due to treatment, the resultant WPNC exhibits an improvement in all the properties like water repellency, dimensional stability, hardness, flexural, tensile and thermal stability compared to untreated wood. (author)

In situ polymerized wood polymer composite: effect of additives and nanoclay on the thermal, mechanical properties

International Nuclear Information System (INIS)

Devi, Rashmi R; Maji, Tarun K.

2013-01-01

This study concerns the preparation and characterization of wood polymer nanocomposites based on impregnation of styrene acrylonitrile co-polymer–nanoclay intercalating system in presence of glycidyl methacrylate (GMA), a cross linking agent, and vinyl trichloro silane (VTCS) as additives into Simul (Bombex ceiba, L.), a soft wood. The effect of nanoclay and VTCS on the properties of the resultant wood polymer nanocomposites (WPNC) has been evaluated. FTIR spectroscopy shows the interaction among wood, polymers, GMA, nanoclay and VTCS. The penetration of polymer and nanoclay into the wood cell wall is supported by SEM study. The distribution of nanoclay in the SAN polymer matrix present within the wood cell wall has been evidenced by TEM study. TGA results show an improvement in the thermostability of the resultant composites. The inclusion of VTCS enhances the self extinguishing behaviour of the WPNC as revealed by limiting oxygen index (LOI) test. Due to treatment, the resultant WPNC exhibits an improvement in all the properties like water repellency, dimensional stability, hardness, flexural, tensile and thermal stability compared to untreated wood. (author)

Wood preservation

Science.gov (United States)

Rebecca E. Ibach

1999-01-01

When left untreated in many outdoor applications, wood becomes subject to degradation by a variety of natural causes. Although some trees possess naturally occurring resistance to decay (Ch. 3, Decay Resistance), many are in short supply or are not grown in ready proximity to markets. Because most commonly used wood species, such as Southern Pine, ponderosa pine, and...

Effects of simplifying fracture network representation on inert chemical migration in fracture-controlled aquifers

Science.gov (United States)

Wellman, Tristan; Shapiro, Allen M.; Hill, Mary C.

2009-01-01

While it is widely recognized that highly permeable 'large-scale' fractures dominate chemical migration in many fractured aquifers, recent studies suggest that the pervasive 'small-scale' fracturing once considered of less significance can be equally important for characterizing the spatial extent and residence time associated with transport processes. A detailed examination of chemical migration through fracture-controlled aquifers is used to advance this conceptual understanding. The influence of fracture structure is evaluated by quantifying the effects to transport caused by a systematic removal of fractures from three-dimensional discrete fracture models whose attributes are derived from geologic and hydrologic conditions at multiple field sites. Results indicate that the effects to transport caused by network simplification are sensitive to the fracture network characteristics, degree of network simplification, and plume travel distance, but primarily in an indirect sense since correlation to individual attributes is limited. Transport processes can be 'enhanced' or 'restricted' from network simplification meaning that the elimination of fractures may increase or decrease mass migration, mean travel time, dispersion, and tailing of the concentration plume. The results demonstrate why, for instance, chemical migration may not follow the classic advection-dispersion equation where dispersion approximates the effect of the ignored geologic structure as a strictly additive process to the mean flow. The analyses further reveal that the prediction error caused by fracture network simplification is reduced by at least 50% using the median estimate from an ensemble of simplified fracture network models, and that the error from network simplification is at least 70% less than the stochastic variability from multiple realizations. Copyright 2009 by the American Geophysical Union.

Fracture toughness of dentin/resin-composite adhesive interfaces.

Science.gov (United States)

Tam, L E; Pilliar, R M

1993-05-01

The reliability and validity of tensile and shear bond strength determinations of dentin-bonded interfaces have been questioned. The fracture toughness value (KIC) reflects the ability of a material to resist crack initiation and unstable propagation. When applied to an adhesive interface, it should account for both interfacial bond strength and inherent defects at or near the interface, and should therefore be more appropriate for characterization of interface fracture resistance. This study introduced a fracture toughness test for the assessment of dentin/resin-composite bonded interfaces. The miniature short-rod specimen geometry was used for fracture toughness testing. Each specimen contained a tooth slice, sectioned from a bovine incisor, to form the bonded interface. The fracture toughness of an enamel-bonded interface was assessed in addition to the dentin-bonded interfaces. Tensile bond strength specimens were also prepared from the dentin surfaces of the cut bovine incisors. A minimum of ten specimens was fabricated for each group of materials tested. After the specimens were aged for 24 h in distilled water at 37 degrees C, the specimens were loaded to failure in an Instron universal testing machine. There were significant differences (p adhesives tested. Generally, both the fracture toughness and tensile bond strength measurements were highest for AllBond 2, intermediate for 3M MultiPurpose, and lowest for Scotchbond 2. Scanning electron microscopy of the fractured specimen halves confirmed that crack propagation occurred along the bond interface during the fracture toughness test. It was therefore concluded that the mini-short-rod fracture toughness test provided a valid method for characterization of the fracture resistance of the dentin-resin composite interface.

The use of new, aqueous chemical wood modifications to improve the durability of wood-plastic composites

Science.gov (United States)

Rebecca E. Ibach; Craig M. Clemons; George C. Chen

2017-01-01

The wood flour used in wood-plastic composites (WPCs) can biologically deteriorate and thus the overall mechanical performance of WPCs decrease when exposed to moisture and fungal decay. Protecting the wood flour by chemical modification can improve the durability of the wood in a nontoxic way so it is not harmful to the environment. WPCs were made with modified wood...

Moisture Transport in Wood

DEFF Research Database (Denmark)

Astrup, Thomas; Hansen, Kurt Kielsgaard; Hoffmeyer, Preben

2005-01-01

Modelling of moisture transport in wood is of great importance as most mechanical and physical properties of wood depend on moisture content. Moisture transport in porous materials is often described by Ficks second law, but several observations indicate that this does not apply very well to wood....... Recently at the Technical University of Denmark, Department of Civil Engineering, a new model for moisture transport in wood has been developed. The model divides the transport into two phases, namely water vapour in the cell lumens and bound water in the cell walls....

The characterization and manipulation of the bacterial microbiome of the Rocky Mountain wood tick, Dermacentor andersoni.

Science.gov (United States)

Clayton, Katie A; Gall, Cory A; Mason, Katheen L; Scoles, Glen A; Brayton, Kelly A

2015-12-10

In North America, ticks are the most economically impactful vectors of human and animal pathogens. The Rocky Mountain wood tick, Dermacentor andersoni (Acari: Ixodidae), transmits Rickettsia rickettsii and Anaplasma marginale to humans and cattle, respectively. In recent years, studies have shown that symbiotic organisms are involved in a number of biochemical and physiological functions. Characterizing the bacterial microbiome of D. andersoni is a pivotal step towards understanding symbiont-host interactions. In this study, we have shown by high-throughput sequence analysis that the composition of endosymbionts in the midgut and salivary glands in adult ticks is dynamic over three generations. Four Proteobacteria genera, Rickettsia, Francisella, Arsenophonus, and Acinetobacter, were identified as predominant symbionts in these two tissues. Exposure to therapeutic doses of the broad-spectrum antibiotic, oxytetracycline, affected both proportions of predominant genera and significantly reduced reproductive fitness. Additionally, Acinetobacter, a free-living ubiquitous microbe, invaded the bacterial microbiome at different proportions based on antibiotic treatment status suggesting that microbiome composition may have a role in susceptibility to environmental contaminants. This study characterized the bacterial microbiome in D. andersoni and determined the generational variability within this tick. Furthermore, this study confirmed that microbiome manipulation is associated with tick fitness and may be a potential method for biocontrol.

Study of Wood Plastic Composites elastic behaviour using full field measurements

Science.gov (United States)

Ben Mbarek, T.; Robert, L.; Hugot, F.; Orteu, J. J.; Sammouda, H.; Graciaa, A.; Charrier, B.

2010-06-01

In this study, the mechanical properties and microstructure of HDPE/wood fibre composites are investigated. The four-point bending and tensile behaviour of Wood Plastic Composite (WPC) with or without additive are studied by using full-field strain measurements by 3-D Digital Image Correlation (3-D DIC). A non-linear behaviour is shown. The modulus of elasticity (MOE) is calculated as the tangent at zero strain of a Maxwell-Bingham model fitted onto experimental data. Four-point bending tests are analyzed thanks to the spatial standard deviation of the longitudinal strain field to determine the degree of heterogeneity. Cyclic tensile tests have been performed in order to analyze the damage of the material. Moreover, Scanning Electron Microscope (SEM) is used to characterize the morphology of the wood fibre/HDPE matrix interface for specimens with maleic anhydride modified polyethylene additive (MAPE).

Inside the guts of wood-eating catfishes: can they digest wood?

Science.gov (United States)

German, Donovan P

2009-11-01

To better understand the structure and function of the gastrointestinal (GI) tracts of wood-eating catfishes, the gross morphology, length, and microvilli surface area (MVSA) of the intestines of wild-caught Panaque nocturnus, P. cf. nigrolineatus "Marañon", and Hypostomus pyrineusi were measured, and contrasted against these same metrics of a closely related detritivore, Pterygoplichthys disjunctivus. All four species had anatomically unspecialized intestines with no kinks, valves, or ceca of any kind. The wood-eating catfishes had body size-corrected intestinal lengths that were 35% shorter than the detritivore. The MVSA of all four species decreased distally in the intestine, indicating that nutrient absorption preferentially takes place in the proximal and mid-intestine, consistent with digestive enzyme activity and luminal carbohydrate profiles for these same species. Wild-caught Pt. disjunctivus, and P. nigrolineatus obtained via the aquarium trade, poorly digested wood cellulose (<33% digestibility) in laboratory feeding trials, lost weight when consuming wood, and passed stained wood through their digestive tracts in less than 4 h. Furthermore, no selective retention of small particles was observed in either species in any region of the gut. Collectively, these results corroborate digestive enzyme activity profiles and gastrointestinal fermentation levels in the fishes' GI tracts, suggesting that the wood-eating catfishes are not true xylivores such as beavers and termites, but rather, are detritivores like so many other fishes from the family Loricariidae.

LCA-based optimization of wood utilization under special consideration of a cascading use of wood.

Science.gov (United States)

Höglmeier, Karin; Steubing, Bernhard; Weber-Blaschke, Gabriele; Richter, Klaus

2015-04-01

Cascading, the use of the same unit of a resource in multiple successional applications, is considered as a viable means to improve the efficiency of resource utilization and to decrease environmental impacts. Wood, as a regrowing but nevertheless limited and increasingly in demand resource, can be used in cascades, thereby increasing the potential efficiency per unit of wood. This study aims to assess the influence of cascading wood utilization on optimizing the overall environmental impact of wood utilization. By combining a material flow model of existing wood applications - both for materials provision and energy production - with an algebraic optimization tool, the effects of the use of wood in cascades can be modelled and quantified based on life cycle impact assessment results for all production processes. To identify the most efficient wood allocation, the effects of a potential substitution of non-wood products were taken into account in a part of the model runs. The considered environmental indicators were global warming potential, particulate matter formation, land occupation and an aggregated single score indicator. We found that optimizing either the overall global warming potential or the value of the single score indicator of the system leads to a simultaneous relative decrease of all other considered environmental impacts. The relative differences between the impacts of the model run with and without the possibility of a cascading use of wood were 7% for global warming potential and the single score indicator, despite cascading only influencing a small part of the overall system, namely wood panel production. Cascading led to savings of up to 14% of the annual primary wood supply of the study area. We conclude that cascading can improve the overall performance of a wood utilization system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Creation of Wood Dust during Wood Processing: Size Analysis, Dust Separation, and Occupational Health

Directory of Open Access Journals (Sweden)

Eva Mračková

2015-11-01

Full Text Available Mechanical separators and fabric filters are being used to remove airborne fine particles generated during the processing and handling of wood. Such particles might have a harmful effect on employee health, not only in small- but also in large-scale wood processing facilities. The amount of wood dust and its dispersion conditions vary according to geometric boundary conditions. Thus, the dispersion conditions could be changed by changing the linear size of the particles. Moreover, the smaller the particles are, the more harmful they can be. It is necessary to become familiar with properties, from a health point of view, of wood dust generated from processing. Wood dust has to be sucked away from the processing area. The fractional separation efficiency of wood dust can be improved using exhaust and filtering devices. Filtration efficiency depends on moisture content, particle size, and device performance. Because of the carcinogenicity of wood dust, the concentration of wood dust in air has to be monitored regularly. Based on the results hereof, a conclusion can be made that both mechanical separators of types SEA and SEB as well as the fabric filters with FINET PES 1 textile are suitable for the separation of wet saw dust from all types of wooden waste produced within the process.

Fracture characteristics of uranium alloys by scanning electron microscopy

International Nuclear Information System (INIS)

Koger, J.W.; Bennett, R.K. Jr.

1976-10-01

The fracture characteristics of uranium alloys were determined by scanning electron microscopy. The fracture mode of stress-corrosion cracking (SCC) of uranium-7.5 weight percent niobium-2.5 weight percent zirconium (Mulberry) alloy, uranium--niobium alloys, and uranium--molybdenum alloys in aqueous chloride solutions is intergranular. The SCC fracture surface of the Mulberry alloy is characterized by very clean and smooth grain facets. The tensile-overload fracture surfaces of these alloys are characteristically ductile dimple. Hydrogen-embrittlement failures of the uranium alloys are brittle and the fracture mode is transgranular. Fracture surfaces of the uranium-0.75 weight percent titanium alloys are quasi cleavage

Natural Protection of Wood with Antagonism Fungi

Directory of Open Access Journals (Sweden)

Alba ZAREMSKI

2011-03-01

Full Text Available Biological environments contain a certain number of microbial populations which, within a givenecological niche, display various relations ranging from symbiosis to parasitism. Researchers have beeninterested in these types of relations for around fifty years, especially in one very particular type ofrelationship: the antagonism exerted between individuals of the same microbial population.Today, the role played by biological agents, bringing into play inhibitive or destructive antibioticsubstances, reveals a certain potential for their use in controlling microorganisms associated with suchdegradation processes.The work undertaken by HydroQuébec and CIRAD involved two types of experiment: 1 in Petri dishes toassess and characterize the antagonistic capacity of Trichoderma against white rot and brown rot fungi; 2on pieces taken from untreated poles in order to study confrontation between the basidiomycete and theantagonistic strain in wood.This study investigated the antagonism of three ascomycetes of the genus Trichoderma against two whiterot basidiomycetes, Pycnoporus sanguineus and Coriolus versicolor, and two brown rot basidiomycetes,Antrodia sp. and Coniophora puteana, through direct confrontation in Petri dishes and in the wood ofHydroQuébec poles.The results obtained seemed to complete each other coherently. They revealed that the Trichodermagroup of fungi was not aggressive to wood and the results obtained after direct confrontation in Petri disheswere confirmed in wood.By directly exposing the different basidiomycetes and antagonists to each other in Petri dishes, two bytwo, we effectively revealed an antagonism effect for a large majority of the pairs. However, there wassubstantial variability in reactions from one pair to the next.

Reactivity and burnout of wood fuels

DEFF Research Database (Denmark)

Dall'Ora, Michelangelo

This thesis deals with the combustion of wood in pulverised fuel power plants. In this type of boiler, the slowest step in the wood conversion process is char combustion, which is one of the factors that not only determine the degree of fuel burnout, but also affect the heat release profile...... of different aspects relevant to wood combustion, including wood structure and composition, wood pyrolysis, wood char properties and wood char oxidation. The full scale campaign, which is the subject of Chapter 3, included sampling of wood fuel before and after milling and sampling of gas and particles...... at the top of the combustion chamber. The collected samples and data are used to obtain an evaluation of the mills in operation at the power plant, the particle size distribution of the wood fuel, as well as the char conversion attained in the furnace. In Chapter 4 an experimental investigation...

Application of molecular genetic methods for identification of wood-decaying fungi in wood constructions

OpenAIRE

Elena Bobeková; Michal Tomšovský; Petr Horáček

2008-01-01

The aim of the paper is to evaluate the utilization of molecular biology methods for detection of wood decaying fungi directly from decomposed wood using a commercial DNA extraction kit developed for soil substrates (PowerSoil™ DNA isolation kit). The experiment based on dry rot fungus (Serpula lacrymans) detection from inoculated wooden pieces under laboratory conditions was followed by field detection of wood-decaying fungi from wood structures on building constructions. Fungal DNA was ide...

An Efficient Upscaling Procedure Based on Stokes-Brinkman Model and Discrete Fracture Network Method for Naturally Fractured Carbonate Karst Reservoirs

KAUST Repository

Qin, Guan

2010-01-01

Naturally-fractured carbonate karst reservoirs are characterized by various-sized solution caves that are connected via fracture networks at multiple scales. These complex geologic features can not be fully resolved in reservoir simulations due to the underlying uncertainty in geologic models and the large computational resource requirement. They also bring in multiple flow physics which adds to the modeling difficulties. It is thus necessary to develop a method to accurately represent the effect of caves, fractures and their interconnectivities in coarse-scale simulation models. In this paper, we present a procedure based on our previously proposed Stokes-Brinkman model (SPE 125593) and the discrete fracture network method for accurate and efficient upscaling of naturally fractured carbonate karst reservoirs.

Adhesive interactions with wood

Science.gov (United States)

Charles R. Frihart

2004-01-01

While the chemistry for the polymerization of wood adhesives has been studied systematically and extensively, the critical aspects of the interaction of adhesives with wood are less clearly understood. General theories of bond formation need to be modified to take into account the porosity of wood and the ability of chemicals to be absorbed into the cell wall....

CHARACTERIZATION OF IN-SITU STRESS AND PERMEABILITY IN FRACTURED RESERVOIRS

Energy Technology Data Exchange (ETDEWEB)

Daniel R. Burns; M. Nafi Toksoz

2002-12-31

We have extended a three-dimensional finite difference elastic wave propagation model previously developed at the Massachusetts Institute of Technology (MIT) Earth Resources Laboratory (ERL) for modeling and analyzing the effect of fractures on seismic waves. The code has been translated into C language and parallelized [using message passing interface (MPI)] to allow for larger models to be run on Linux PC computer clusters. We have also obtained another 3-D code from Lawrence Berkeley Laboratory, which we will use for verification of our ERL code results and also to run discrete fracture models. Testing of both codes is underway. We are working on a new finite difference model of borehole wave propagation for stressed formations. This code includes coordinate stretching to provide stable, variable grid sizes that will allow us to model the thin fluid annulus layers in borehole problems, especially for acoustic logging while drilling (LWD) applications. We are also extending our analysis routines for the inversion of flexural wave dispersion measurements for in situ stress estimates. Initial results on synthetic and limited field data are promising for a method to invert cross dipole data for the rotation angle and stress state simultaneously. A meeting is being scheduled between MIT and Shell Oil Company scientists to look at data from a fractured carbonate reservoir that may be made available to the project. The Focus/Disco seismic processing system from Paradigm Geophysical has been installed at ERL for field data analysis and as a platform for new analysis modules. We have begun to evaluate the flow properties of discrete fracture distributions through a simple 2D numerical model. Initial results illustrate how fluid flow pathways are very sensitive to variations in the geometry and apertures of fracture network.

Composite structure of wood cells in petrified wood

International Nuclear Information System (INIS)

Nowak, Jakub; Florek, Marek; Kwiatek, Wojciech; Lekki, Janusz; Chevallier, Pierre; Zieba, Emil; Mestres, Narcis; Dutkiewicz, E.M.; Kuczumow, Andrzej

2005-01-01

Special kinds of petrified wood of complex structure were investigated. All the samples were composed of at least two different inorganic substances. The original cell structure was preserved in each case. The remnants of the original biological material were detected in some locations, especially in the cell walls. The complex inorganic structure was superimposed on the remnant organic network. The first inorganic component was located in the lumena (l.) of the cells while another one in the walls (w.) of the cells. The investigated arrangements were as follows: calcite (l.)-goethite-hematite (w.)-wood from Dunarobba, Italy; pyrite (l.)-calcite (w.)-wood from Lukow, Poland; goethite (l.)-silica (w.)-wood from Kwaczala, Poland. The inorganic composition was analysed and spatially located by the use of three spectral methods: electron microprobe, X-ray synchrotron-based microprobe, μ-PIXE microprobe. The accurate mappings presenting 2D distribution of the chemical species were presented for each case. Trace elements were detected and correlated with the distribution of the main elements. In addition, the identification of phases was done by the use of μ-Raman and μ-XRD techniques for selected and representative points. The possible mechanisms of the described arrangements are considered. The potential synthesis of similar structures and their possible applications are suggested

Composite structure of wood cells in petrified wood

Energy Technology Data Exchange (ETDEWEB)

Nowak, Jakub [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland); Florek, Marek [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland); Kwiatek, Wojciech [Institute of Nuclear Physics, Department of Nuclear Spectroscopy, 31-342 Cracow (Poland); Lekki, Janusz [Institute of Nuclear Physics, Department of Nuclear Spectroscopy, 31-342 Cracow (Poland); Chevallier, Pierre [LPS, CEN Saclay et LURE, Universite Paris-Sud, Bat 209D, F-91405 Orsay (France); Zieba, Emil [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland); Mestres, Narcis [Institut de Ciencia de Materials de Barcelona (ICMAB), Campus de la UAB, E-08193-Bellaterra (Spain); Dutkiewicz, E.M. [Institute of Nuclear Physics, Department of Nuclear Spectroscopy, 31-342 Cracow (Poland); Kuczumow, Andrzej [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland)

2005-04-28

Special kinds of petrified wood of complex structure were investigated. All the samples were composed of at least two different inorganic substances. The original cell structure was preserved in each case. The remnants of the original biological material were detected in some locations, especially in the cell walls. The complex inorganic structure was superimposed on the remnant organic network. The first inorganic component was located in the lumena (l.) of the cells while another one in the walls (w.) of the cells. The investigated arrangements were as follows: calcite (l.)-goethite-hematite (w.)-wood from Dunarobba, Italy; pyrite (l.)-calcite (w.)-wood from Lukow, Poland; goethite (l.)-silica (w.)-wood from Kwaczala, Poland. The inorganic composition was analysed and spatially located by the use of three spectral methods: electron microprobe, X-ray synchrotron-based microprobe, {mu}-PIXE microprobe. The accurate mappings presenting 2D distribution of the chemical species were presented for each case. Trace elements were detected and correlated with the distribution of the main elements. In addition, the identification of phases was done by the use of {mu}-Raman and {mu}-XRD techniques for selected and representative points. The possible mechanisms of the described arrangements are considered. The potential synthesis of similar structures and their possible applications are suggested.

Sustainable wood waste management in Nigeria

Directory of Open Access Journals (Sweden)

Owoyemi Jacob Mayowa

2016-09-01

Full Text Available Wood industries produce large volumes of residues which must be utilized, marketed or properly disposed of. Heaps of wood residues are common features in wood industries throughout the year. In Nigeria, this residue is generally regarded as waste and this has led to open burning practices, dumping in water bodies or dumping in an open area which constitutes environmental pollution. Sawmills in Nigeria generated over 1,000,000 m3 of wood waste in 2010 while about 5000 m3 of waste was generated in plywood mills. Nigeria generates about 1.8 million tons of sawdust annually and 5.2 million tons of wood wastes. The impact of improper disposal of waste wood on the environment affects both the aquatic and terrestrial ecosystems. Also burning of waste wood releases greenhouse gases into the atmosphere causing various health issues. Reuse/recycling of these wood residues in Nigeria will reduce the pressure on our ever decreasing forests, reduce environmental pollution, create wealth and employment. The literature available on this subject was reviewed and this article, therefore, focuses on the various methods of wood waste disposal and its utilization in Nigerian wood industries, the effects of wood waste on the environment as well as on human health and the benefits of proper wood waste management practices.

Non-linear imaging condition to image fractures as non-welded interfaces

NARCIS (Netherlands)

Minato, S.; Ghose, R.

2014-01-01

Hydraulic properties of a fractured reservoir are often controlled by large fractures. In order to seismically detect and characterize them, a high-resolution imaging method is necessary. We apply a non-linear imaging condition to image fractures, considered as non-welded interfaces. We derive the

The Behaviour of Fracture Growth in Sedimentary Rocks: A Numerical Study Based on Hydraulic Fracturing Processes

Directory of Open Access Journals (Sweden)

Lianchong Li

2016-03-01

Full Text Available To capture the hydraulic fractures in heterogeneous and layered rocks, a numerical code that can consider the coupled effects of fluid flow, damage, and stress field in rocks is presented. Based on the characteristics of a typical thin and inter-bedded sedimentary reservoir, China, a series of simulations on the hydraulic fracturing are performed. In the simulations, three points, i.e., (1 confining stresses, representing the effect of in situ stresses, (2 strength of the interfaces, and (3 material properties of the layers on either side of the interface, are crucial in fracturing across interfaces between two adjacent rock layers. Numerical results show that the hydrofracture propagation within a layered sequence of sedimentary rocks is controlled by changing in situ stresses, interface properties, and lithologies. The path of the hydraulic fracture is characterized by numerous deflections, branchings, and terminations. Four types of potential interaction, i.e., penetration, arrest, T-shaped branching, and offset, between a hydrofracture and an interface within the layered rocks are formed. Discontinuous composite fracture segments resulting from out-of-plane growth of fractures provide a less permeable path for fluids, gas, and oil than a continuous planar composite fracture, which are one of the sources of the high treating pressures and reduced fracture volume.

Kinematic and geometric characterization of the fracturation in the Berrocal (Toledo, Spain)

International Nuclear Information System (INIS)

Campos Egea, R.; Gumiel Martinez, P.; Pardillo Porras, J.

1995-01-01

The current research carried out it the El Berrocal Test Site belong to the ''Caracterizacion y validacion de los procesos de migracion de radionucleidos bajo condiciones reales en un medio granitico fracturado Project'', which is integrated in the ENRESA and EE R+D Programs aimed to establish the structural, lithological, geochemical, hydrochemical and hydrogeological aspects of the granite-Uranium mineralization system, to approach modelling of the U-Migration. The geometry and kinematics of fracturing which affect the El Berroal granite are shown in this paper. The kinematics of Late-Hercynian fractures is consistent with the development of an extension dilation zone off-set between the Meridional of Central System and Navamorcuente major faults, in a continued right-lateral shearing, accompanying E-W shortening in prolonged transpression. An statistical analysis of 1264 joints have been carried out. Joint spacing and aperture were also measured in profiles around the El Berrocal Test Site showing that joints may be grouped in three groups with orientations following Fisher distributions. Joint spacing shows fractal behaviour with a significant superimposed ramdon element (negative-exponential distribution) which is at present being evaluated. Finally, fracture trace mapping and detected fracture zones in boreholes from TLV data have been geometrically correlated and utilized to asses fracture connectivity. Connected networks of fractures have been obtained, which is a support fort further hydraulic tests carried out in the Porject. (Author) 53 refs

Verification and characterization of continuum behavior of fractured rock at AECL Underground Research Laboratory

International Nuclear Information System (INIS)

Long, J.C.S.

1985-02-01

The purposes of this study are to determine when a fracture system behaves as a porous medium and what the corresponding permeability tensor is. A two-dimensional fracture system model is developed with density, size, orientation, and location of fractures in an impermeable matrix as random variables. Simulated flow tests through the models measure directional permeability, K/sub g/. Polar coordinate plots of 1/√K/sub g/, which are ellipses for equivalent anistropic homogeneous porous media, are graphed and best fit ellipses are calculated. Fracture length and areal density were varied such that fracture frequency was held constant. The examples showed the permeability increased with fracture length. The modeling techniques were applied to data from the Atomic Energy of Canada Ltd.'s Underground Research Laboratory facility in Manitoba, Canada by assuming the fracture pattern at the surface persists at depth. Well test data were used to estimate the aperture distribution by both correlating and not correlating the aperture with fracture length. The permeability of models with uncorrelated length and aperture were smaller than those for correlated models. A Monte Carlo type study showed that analysis of steady state packer tests consistently underestimate the mean aperture. Finally, a three-dimensional model in which fractures are discs randomly located in space, interactions between the fractures are line segments, and the solution of the steady state flow equations is based on image theory was discussed

Structure and function of wood

Science.gov (United States)

Alex Wiedenhoeft

2010-01-01

Wood is a complex biological structure, a composite of many chemistries and cell types acting together to serve the needs of a living plant. Attempting to understand wood in the context of wood technology, we have often overlooked the key and basic fact that wood evolved over the course of millions of years to serve three main functions in plants― conduction of water...

Characterization of fractures and flow zones in a contaminated crystalline-rock aquifer in the Tylerville section of Haddam, Connecticut

Science.gov (United States)

Johnson, Carole D.; Kiel, Kristal F.; Joesten, Peter K.; Pappas, Katherine L.

2016-10-04

The U.S. Geological Survey, in cooperation with the Connecticut Department of Energy and Environmental Protection, investigated the characteristics of the bedrock aquifer in the Tylerville section of Haddam, Connecticut, from June to August 2014. As part of this investigation, geophysical logs were collected from six water-supply wells and were analyzed to (1) identify well construction, (2) determine the rock type and orientation of the foliation and layering of the rock, (3) characterize the depth and orientation of fractures, (4) evaluate fluid properties of the water in the well, and (5) determine the relative transmissivity and head of discrete fractures or fracture zones. The logs included the following: caliper, electromagnetic induction, gamma, acoustic and (or) optical televiewer, heat-pulse flowmeter under ambient and pumped conditions, hydraulic head data, fluid electrical conductivity and temperature under postpumping conditions, and borehole-radar reflection collected in single-hole mode. In a seventh borehole, a former water-supply well, only caliper, fluid electrical conductivty, and temperature logs were collected, because of a constriction in the borehole.This report includes a description of the methods used to collect and process the borehole geophysical data, the description of the data collected in each of the wells, and a comparison of the results collected in all of the wells. The data are presented in plots of the borehole geophysical logs, tables, and figures. Collectively these data provide valuable characterizations that can be used to improve or inform site conceptual models of groundwater flow in the study area.

Wood pellets : a worldwide fuel commodity

International Nuclear Information System (INIS)

Melin, S.

2005-01-01

Aspects of the wood pellet industry were discussed in this PowerPoint presentation. Details of wood pellets specifications were presented, and the wood pellet manufacturing process was outlined. An overview of research and development activities for wood pellets was presented, and issues concerning quality control were discussed. A chart of the effective calorific value of various fuels was provided. Data for wood pellet mill production in Canada, the United States and the European Union were provided, and various markets for Canadian wood pellets were evaluated. Residential sales as well as Canadian overseas exports were reviewed. Production revenues for British Columbia and Alberta were provided. Wood pellet heat and electricity production were discussed with reference to prefabricated boilers, stoves and fireplaces. Consumption rates, greenhouse gas (GHG) emissions, and fuel ratios for wood pellets and fossil fuels were compared. Price regulating policies for electricity and fossil fuels have prevented the domestic expansion of the wood pellet industry. There are currently no incentives for advanced biomass combustion to enter British Columbia markets, and this has led to the export of wood pellets. It was concluded that climate change mitigation policies will be a driving force behind market expansion for wood pellets. tabs., figs

Acoustic and adsorption properties of submerged wood

Science.gov (United States)

Hilde, Calvin Patrick

Wood is a common material for the manufacture of many products. Submerged wood, in particular, is used in niche markets, such as the creation of musical instruments. An initial study performed on submerged wood from Ootsa Lake, British Columbia, provided results that showed that the wood was not suitable for musical instruments. This thesis re-examined the submerged wood samples. After allowing the wood to age unabated in a laboratory setting, the wood was retested under the hypothesis that the physical acoustic characteristics would improve. It was shown, however, that the acoustic properties became less adequate after being left to sit. The adsorption properties of the submerged wood were examined to show that the submerged wood had a larger accessible area of wood than that of control wood samples. This implied a lower amount of crystalline area within the submerged wood. From the combined adsorption and acoustic data for the submerged wood, relationships between the moisture content and speed of sound were created and combined with previous research to create a proposed model to describe how the speed of sound varies with temperature, moisture content and the moisture content corresponding to complete hydration of sorption sites within the wood.

Dimensional threshold for fracture linkage and hooking

Science.gov (United States)

Lamarche, Juliette; Chabani, Arezki; Gauthier, Bertrand D. M.

2018-03-01

Fracture connectivity in rocks depends on spatial properties of the pattern including length, abundance and orientation. When fractures form a single-strike set, they hardly cross-cut each other and the connectivity is limited. Linkage probability increases with increasing fracture abundance and length as small fractures connect to each other to form longer ones. A process for parallel fracture linkage is the "hooking", where two converging fracture tips mutually deviate and then converge to connect due to the interaction of their crack-tip stresses. Quantifying the processes and conditions for fracture linkage in single-strike fracture sets is crucial to better predicting fluid flow in Naturally Fractured Reservoirs. For 1734 fractures in Permian shales of the Lodève Basin, SE France, we measured geometrical parameters in 2D, characterizing three stages of the hooking process: underlapping, overlapping and linkage. We deciphered the threshold values, shape ratios and limiting conditions to switch from one stage to another one. The hook set up depends on the spacing (S) and fracture length (Lh) with the relation S ≈ 0.15 Lh. Once the hooking is initiated, with the fracture deviation length (L) L ≈ 0.4 Lh, the fractures reaches the linkage stage only when the spacing is reduced to S ≈ 0.02 Lh and the convergence (C) is < 0.1 L. These conditions apply to multi-scale fractures with a shape ratio L/S = 10 and for fracture curvature of 10°-20°.

EFFECT OF LIGNIN CONTENT OF Eucalyptus globulus WOOD IN KRAFT PULPING PERFORMANCE

Directory of Open Access Journals (Sweden)

Gabriel Valim Cardoso

2011-03-01

Full Text Available In this research, it was analyzed the lignin content effect of Eucalyptus globulus wood in kraft pulping optimization. Seventy-two laboratory cooking were made with wood chips obtained from six Eucalyptus globulus trees selected from a group of 50 trees. The wood chips from three trees with the lowest lignin content, with average 20,53%, were mixed proportionally based on the tree weights, obtaining the sample of low lignin content wood. The same was made to obtain the sample for wood chips with the highest lignin content, with average 23,02%. The two lignin levels were statistically different. The two wood samples had basic densities statistically not different. Using three maximum temperatures levels (160, 165 and 170ºC, and three active alkali charged (17, 18,5 and 20%, the wood chips were converted to kraft pulps. The pulps were then characterized to analyze the influence of the distinct treatments employed in the cooking on their properties. The effect of the cooking conditions was expressed by mathematical models in order to determine the optimum points for each of the evaluated properties. The optimization process indicated maximum temperature of 168ºC, and active alkali of 19%, for maximum kraft pulping yield to achieve kappa number 18; this result was for woods with low lignin content. For woods containing the high lignin content, the optimization showed maximum cooking temperature of 169ºC and active alkali of 19% for kappa number of 18. The average reduction of 2,49% in wood lignin content resulted a correspondent gain of 2,2% in the kraft yield (o.d. basis and a reduction on the active alkali charge of 1,2% (o.d. basis to achieve kappa numbers from 16 to 19, preserving pulp properties. If the option is to work with kappa number 19 instead of 16, the gain in kraft yield is approximately 2%. Therefore, when working with low lignin content wood and kappa number 19 instead of 16, a substantial gain of approximately 4,2% is obtained

Urban Wood Waste Resource Assessment; TOPICAL

International Nuclear Information System (INIS)

Wiltsee, G.

1998-01-01

This study collected and analyzed data on urban wood waste resources in 30 randomly selected metropolitan areas in the United States. Three major categories wood wastes disposed with, or recovered from, the municipal solid waste stream; industrial wood wastes such as wood scraps and sawdust from pallet recycling, woodworking shops, and lumberyards; and wood in construction/demolition and land clearing debris

Fast Physically Accurate Rendering of Multimodal Signatures of Distributed Fracture in Heterogeneous Materials.

Science.gov (United States)

Visell, Yon

2015-04-01

This paper proposes a fast, physically accurate method for synthesizing multimodal, acoustic and haptic, signatures of distributed fracture in quasi-brittle heterogeneous materials, such as wood, granular media, or other fiber composites. Fracture processes in these materials are challenging to simulate with existing methods, due to the prevalence of large numbers of disordered, quasi-random spatial degrees of freedom, representing the complex physical state of a sample over the geometric volume of interest. Here, I develop an algorithm for simulating such processes, building on a class of statistical lattice models of fracture that have been widely investigated in the physics literature. This algorithm is enabled through a recently published mathematical construction based on the inverse transform method of random number sampling. It yields a purely time domain stochastic jump process representing stress fluctuations in the medium. The latter can be readily extended by a mean field approximation that captures the averaged constitutive (stress-strain) behavior of the material. Numerical simulations and interactive examples demonstrate the ability of these algorithms to generate physically plausible acoustic and haptic signatures of fracture in complex, natural materials interactively at audio sampling rates.

Moisture Performance of wood-plastic composites reinforced with extracted and delignified wood flour

Science.gov (United States)

Yao Chen; Nicole M. Stark; Mandla A. Tshabalala; Jianmin Gao; Yongming Fan

2014-01-01

This study investigated the effect of using extracted and delignified wood flour on water sorption properties of wood–plastic composites. Wood flour (WF) extraction was performed with three solvent systems: toluene/ethanol (TE), acetone/water (AW), and hot water (HW); delignification was conducted using sodium chlorite/acetic acid solution. A 24 full-factorial...

Survival, growth, wood basic density and wood biomass of seven ...

African Journals Online (AJOL)

A performance comparison of seven-year-old individuals of 13 Casuarina species/provenances in terms of survival, growth (diameter, height and volume), wood basic density and wood biomass was undertaken at Kongowe, Kibaha, Tanzania. The trial was laid out using a randomised complete block design with four ...

Chapter 9: Wood Energy

Science.gov (United States)

Francisco X. Aguilar; Karen Abt; Branko Glavonjic; Eugene Lopatin; Warren  Mabee

2016-01-01

The availabilty of information on wood energy continues to improve, particularly for commoditized woodfuels.  Wood energy consumption and production vary in the UNECE region because demand is strngly affected by weather and the prices of competing energy sources.  There has been an increase in wood energy in the power-and-heat sector in the EU28 and North American...

Iron Stain on Wood

Science.gov (United States)

Mark Knaebe

2013-01-01

Iron stain, an unsightly blue–black or gray discoloration, can occur on nearly all woods. Oak, redwood, cypress, and cedar are particularly prone to iron stain because these woods contain large amounts of tannin-like extractives. The discoloration is caused by a chemical reaction between extractives in the wood and iron in steel products, such as nails, screws, and...

New C2 synchondrosal fracture classification system

Energy Technology Data Exchange (ETDEWEB)

Rusin, Jerome A.; Ruess, Lynne [Department of Radiology, Nationwide Children' s Hospital, Columbus, OH (United States); The Ohio State University College of Medicine and Public Health, Columbus, OH (United States); Daulton, Robert S. [Department of Radiology, Nationwide Children' s Hospital, Columbus, OH (United States)

2015-06-15

Excessive cervical flexion-extension accompanying mild to severe impact injuries can lead to C2 synchondrosal fractures in young children. To characterize and classify C2 synchondrosal fracture patterns. We retrospectively reviewed imaging and medical records of children who were treated for cervical spine fractures at our institution between 1995 and 2014. We reviewed all fractures involving the five central C2 synchondroses with regard to patient demographics, mechanism of injury, fracture pattern, associated fractures and other injuries, treatment plans and outcome. Fourteen children had fractures involving the central C2 synchondroses. There were nine boys and five girls, all younger than 6 years. We found four distinct fracture patterns. Eleven complete fractures were further divided into four subtypes (a, b, c and d) based on degree of anterior displacement of the odontoid segment and presence of distraction. Nine of these 11 children had fractures through both odontoneural synchondroses and the odontocentral synchondrosis; one had fractures involving both neurocentral synchondroses and the odontoneural synchondrosis; one had fractures through bilateral odontoneural and bilateral neurocentral synchondroses. Three children had incomplete fractures, defined as a fracture through a single odontoneural synchondrosis with or without partial extension into either the odontocentral or the adjacent neurocentral synchondroses. All complete fractures were displaced or angulated. Four had associated spinal cord injury, including two contusions (subtype c fractures) and two fatal transections (subtype d fractures). Most children were treated with primary halo stabilization. Subtype c fractures required surgical fixation. We describe four patterns of central C2 synchondrosal fractures, including two unique patterns that have not been reported. We propose a classification system to distinguish these fractures and aid in treatment planning. (orig.)

Exterior Decay of Wood-Plastic Composite Boards: Characterization and Magnetic Resonance Imaging

Science.gov (United States)

Rebecca Ibach; Grace Sun; Marek Gnatowski; Jessie Glaeser; Mathew Leung; John Haight

2016-01-01

Magnetic resonance imaging (MRI) was used to evaluate free water content and distribution in wood-plastic composite (WPC) materials decayed during exterior exposure near Hilo, Hawaii. Two segments of the same board blend were selected from 6 commercial decking boards that had fungal fruiting bodies. One of the two board segments was exposed in sun, the other in shadow...

Characterization and electrodialytic treatment of wood combustion fly ash for removal of cadmium

DEFF Research Database (Denmark)

Pedersen, Anne Juul

2003-01-01

especially contain amounts of the toxic heavy metal cadmium that may exceed the limiting values for agricultural utilisation given by the Danish Environmental Protection Agency.In this work the advances of using an electrodialytic remediation method to reduce the Cd content in wood combustion fly ash...... conditions. However, significant amounts of Cd could be extracted at neutral to alkaline conditions using an ammonium citrate solution as a desorption agent.Electrodialytic remediation experiments showed that, under optimised remediation conditions using a mixture of ammonium citrate (0.25M) and NH"3 (1.......25%) as an assisting agent, more than 70% of the initial Cd could be removed from the wood fly ash. The results also indicated that a continuous out-separation of Cd from the aqueous process solutions is possible. Thereby, recycling of the (nutrient rich) process solutions as well as of the remediated ash seems...

On-line automatic detection of wood pellets in pneumatically conveyed wood dust flow

Science.gov (United States)

Sun, Duo; Yan, Yong; Carter, Robert M.; Gao, Lingjun; Qian, Xiangchen; Lu, Gang

2014-04-01

This paper presents a piezoelectric transducer based system for on-line automatic detection of wood pellets in wood dust flow in pneumatic conveying pipelines. The piezoelectric transducer senses non-intrusively the collisions between wood pellets and the pipe wall. Wavelet-based denoising is adopted to eliminate environmental noise and recover the collision events. Then the wood pellets are identified by sliding a time window through the denoised signal with a suitable threshold. Experiments were carried out on a laboratory test rig and on an industrial pneumatic conveying pipeline to assess the effectiveness and operability of the system.

Discrete fracture modelling for the Stripa tracer validation experiment predictions

International Nuclear Information System (INIS)

Dershowitz, W.; Wallmann, P.

1992-02-01

Groundwater flow and transport through three-dimensional networks of discrete fractures was modeled to predict the recovery of tracer from tracer injection experiments conducted during phase 3 of the Stripa site characterization and validation protect. Predictions were made on the basis of an updated version of the site scale discrete fracture conceptual model used for flow predictions and preliminary transport modelling. In this model, individual fractures were treated as stochastic features described by probability distributions of geometric and hydrologic properties. Fractures were divided into three populations: Fractures in fracture zones near the drift, non-fracture zone fractures within 31 m of the drift, and fractures in fracture zones over 31 meters from the drift axis. Fractures outside fracture zones are not modelled beyond 31 meters from the drift axis. Transport predictions were produced using the FracMan discrete fracture modelling package for each of five tracer experiments. Output was produced in the seven formats specified by the Stripa task force on fracture flow modelling. (au)

Wood Chemical Composition in Species of Cactaceae: The Relationship between Lignification and Stem Morphology

Science.gov (United States)

Canché-Escamilla, Gonzalo; Soto-Hernández, Marcos

2015-01-01

In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs) and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content) in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous) with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35%) of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level. PMID:25880223

Wood chemical composition in species of Cactaceae: the relationship between lignification and stem morphology.

Directory of Open Access Journals (Sweden)

Jorge Reyes-Rivera

Full Text Available In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35% of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level.

Wood chemical composition in species of Cactaceae: the relationship between lignification and stem morphology.

Science.gov (United States)

Reyes-Rivera, Jorge; Canché-Escamilla, Gonzalo; Soto-Hernández, Marcos; Terrazas, Teresa

2015-01-01

In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs) and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content) in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous) with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35%) of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level.

Wood density and anatomy of three Eucalyptus species: implications for hydraulic conductivity

International Nuclear Information System (INIS)

Barotto, A.J.; Monteoliva, S.; Gyenge, J.; Martínez-Meier, A.; Moreno, K.; Tesón, N.; Fernández, M.E.

2017-01-01

Aim of the study: To characterize wood anatomical traits of three Eucalyptus species that differ in wood density and ecological requirements, and to examine the relationships between some anatomical features, wood density, and theoretical xylem hydraulic conductivity (Ks). Area of study: We analyzed 86 trees from three sites of Argentina (Entre Ríos and Buenos Aires Provinces). Methods: The sampled trees were Eucalyptus globulus, E. grandis and E. viminalis ranging from 11 to 15 years old. One stem disc was cut from each tree to determine wood density and identify quantitative anatomical features of vessels and fibers. Vessel composition (S, size - to-number ratio, a measure of vessel size distribution) and lumen fraction (F, the total sapwood area available for water transport) were estimated. Results: E. grandis, the species with the highest growth rates, presented the highest theoretical Ks. This was associated with anatomical features such as a high density of wide vessels resulting in high F. On the other hand, E. viminalis, the species with the lowest growth rates and highest resistance to environmental stress, showed lower Ks as a result of a low density of wide vessels. These two species differed not only greatly in wood density but also in fiber characteristics. In the case of E. globulus, vessels were relatively narrow, which resulted in the lowest theoretical Ks, fibers were small, and wood density intermediate. Research highlights: F had greater influence on Ks than S. The anatomical characteristics and wood density could only partly explain the differential growth or resistance to stress of the studied species.

Wood density and anatomy of three Eucalyptus species: implications for hydraulic conductivity

Directory of Open Access Journals (Sweden)

Antonio J. Barotto

2017-05-01

Full Text Available Aim of the study: To characterize wood anatomical traits of three Eucalyptus species that differ in wood density and ecological requirements, and to examine the relationships between some anatomical features, wood density, and theoretical xylem hydraulic conductivity (Ks. Area of study: We analyzed 86 trees from three sites of Argentina (Entre Ríos and Buenos Aires Provinces. Methods: The sampled trees were Eucalyptus globulus, E. grandis and E. viminalis ranging from 11 to 15 years old. One stem disc was cut from each tree to determine wood density and identify quantitative anatomical features of vessels and fibers. Vessel composition (S, size - to-number ratio, a measure of vessel size distribution and lumen fraction (F, the total sapwood area available for water transport were estimated. Results: E. grandis, the species with the highest growth rates, presented the highest theoretical Ks. This was associated with anatomical features such as a high density of wide vessels resulting in high F. On the other hand, E. viminalis, the species with the lowest growth rates and highest resistance to environmental stress, showed lower Ks as a result of a low density of wide vessels. These two species differed not only greatly in wood density but also in fiber characteristics. In the case of E. globulus, vessels were relatively narrow, which resulted in the lowest theoretical Ks, fibers were small, and wood density intermediate. Research highlights: F had greater influence on Ks than S. The anatomical characteristics and wood density could only partly explain the differential growth or resistance to stress of the studied species.

Wood density and anatomy of three Eucalyptus species: implications for hydraulic conductivity

Energy Technology Data Exchange (ETDEWEB)

Barotto, A.J.; Monteoliva, S.; Gyenge, J.; Martínez-Meier, A.; Moreno, K.; Tesón, N.; Fernández, M.E.

2017-11-01

Aim of the study: To characterize wood anatomical traits of three Eucalyptus species that differ in wood density and ecological requirements, and to examine the relationships between some anatomical features, wood density, and theoretical xylem hydraulic conductivity (Ks). Area of study: We analyzed 86 trees from three sites of Argentina (Entre Ríos and Buenos Aires Provinces). Methods: The sampled trees were Eucalyptus globulus, E. grandis and E. viminalis ranging from 11 to 15 years old. One stem disc was cut from each tree to determine wood density and identify quantitative anatomical features of vessels and fibers. Vessel composition (S, size - to-number ratio, a measure of vessel size distribution) and lumen fraction (F, the total sapwood area available for water transport) were estimated. Results: E. grandis, the species with the highest growth rates, presented the highest theoretical Ks. This was associated with anatomical features such as a high density of wide vessels resulting in high F. On the other hand, E. viminalis, the species with the lowest growth rates and highest resistance to environmental stress, showed lower Ks as a result of a low density of wide vessels. These two species differed not only greatly in wood density but also in fiber characteristics. In the case of E. globulus, vessels were relatively narrow, which resulted in the lowest theoretical Ks, fibers were small, and wood density intermediate. Research highlights: F had greater influence on Ks than S. The anatomical characteristics and wood density could only partly explain the differential growth or resistance to stress of the studied species.

Introduction to numerical modeling of thermohydrologic flow in fractured rock masses

International Nuclear Information System (INIS)

Wang, J.S.Y.

1980-01-01

More attention is being given to the possibility of nuclear waste isolation in hard rock formations. The waste will generate heat which raises the temperature of the surrounding fractured rock masses and induces buoyancy flow and pressure change in the fluid. These effects introduce the potential hazard of radionuclides being carried to the biosphere, and affect the structure of a repository by stress changes in the rock formation. The thermohydrological and thermomechanical responses are determined by the fractures as well as the intact rock blocks. The capability of modeling fractured rock masses is essential to site characterization and repository evaluation. The fractures can be modeled either as a discrete system, taking into account the detailed fracture distributions, or as a continuum representing the spatial average of the fractures. A numerical model is characterized by the governing equations, the numerical methods, the computer codes, the validations, and the applications. These elements of the thermohydrological models are discussed. Along with the general review, some of the considerations in modeling fractures are also discussed. Some remarks on the research needs in modeling fractured rock mass conclude the paper

State-of-the-art of the European regulation on wood wastes and wood ashes valorization. Synthesis

International Nuclear Information System (INIS)

Mousseau, S.

2007-01-01

This study has the objective of comparing the regulations of 10 European countries with that of France, in relation to the classification and recycling of wood waste, in particular lightly treated wood, as well as recycling of wood ash. The first part relating to wood waste presents a detailed analysis by country as well as a summary, on the one hand, of the various sectors for recycling waste wood and, on the other, the emission limits for their energy recovery. Generally, there is a distinction between waste covered by the incineration directive, and the others, without any particular category for lightly treated wood. However, recommendations emerge from this that are based essentially on the regulations or guidelines observed in Germany, Austria and the United Kingdom. The second part relating to wood ash also a presents a detailed analysis by country as well as a summary of the various sectors of recycling and limit values for spreading. Ash is generally considered as waste, and is recycled on a case-by case basis. Only Germany and Austria have clearly integrated wood ash in their regulatory framework. Overall this study shows the need for uniform regulation at European level, establishing environment requirements for recycling wood waste and wood ash, in order to encourage development of the use of biomass

Influence of summer biogeography on wood warbler stopover abundance

Science.gov (United States)

Jeffrey F. Kelly; Rob Smith; Deborah M. Finch; Frank R. Moore; Wang Yong

1999-01-01

We evaluated the effect of summer biogeography of migrant wood warblers (Parulidae) on their stopover abundance. To characterize abundance patterns, we used mist-net capture data from spring and fall migration in the Middle Rio Grande Valley, New Mexico, spring migration on the Gulf Coast of Louisiana, and fall migration on the Gulf Coast of Alabama. To describe the...

Study of Wood Plastic Composites elastic behaviour using full field measurements

Directory of Open Access Journals (Sweden)

Graciaa A.

2010-06-01

Full Text Available In this study, the mechanical properties and microstructure of HDPE/wood fibre composites are investigated. The four-point bending and tensile behaviour of Wood Plastic Composite (WPC with or without additive are studied by using full-field strain measurements by 3-D Digital Image Correlation (3-D DIC. A non-linear behaviour is shown. The modulus of elasticity (MOE is calculated as the tangent at zero strain of a Maxwell-Bingham model fitted onto experimental data. Four-point bending tests are analyzed thanks to the spatial standard deviation of the longitudinal strain field to determine the degree of heterogeneity. Cyclic tensile tests have been performed in order to analyze the damage of the material. Moreover, Scanning Electron Microscope (SEM is used to characterize the morphology of the wood fibre/HDPE matrix interface for specimens with maleic anhydride modified polyethylene additive (MAPE.

Investigating the molecular underpinnings underlying morphology and changes in carbon partitioning during tension wood formation in Eucalyptus.

Science.gov (United States)

Mizrachi, Eshchar; Maloney, Victoria J; Silberbauer, Janine; Hefer, Charles A; Berger, Dave K; Mansfield, Shawn D; Myburg, Alexander A

2015-06-01

Tension wood has distinct physical and chemical properties, including altered fibre properties, cell wall composition and ultrastructure. It serves as a good system for investigating the genetic regulation of secondary cell wall biosynthesis and wood formation. The reference genome sequence for Eucalyptus grandis allows investigation of the global transcriptional reprogramming that accompanies tension wood formation in this global wood fibre crop. We report the first comprehensive analysis of physicochemical wood property changes in tension wood of Eucalyptus measured in a hybrid (E. grandis × Eucalyptus urophylla) clone, as well as genome-wide gene expression changes in xylem tissues 3 wk post-induction using RNA sequencing. We found that Eucalyptus tension wood in field-grown trees is characterized by an increase in cellulose, a reduction in lignin, xylose and mannose, and a marked increase in galactose. Gene expression profiling in tension wood-forming tissue showed corresponding down-regulation of monolignol biosynthetic genes, and differential expression of several carbohydrate active enzymes. We conclude that alterations of cell wall traits induced by tension wood formation in Eucalyptus are a consequence of a combination of down-regulation of lignin biosynthesis and hemicellulose remodelling, rather than the often proposed up-regulation of the cellulose biosynthetic pathway. © 2014 University of Pretoria New Phytologist © 2014 New Phytologist Trust.

Wood Flour Moulding Technology: Implications for Technical ...

African Journals Online (AJOL)

The intent of this article is to demonstrate how wood waste called sawdust or wood flour can be transformed by plastic moulding machine into items of economic value. Wood flour is wood reduced to very fine particle form. It can be waste product from saw mills, wood working plants or produced from selected dry wood by ...

Wood wastes: Uses

International Nuclear Information System (INIS)

Cipro, A.

1993-01-01

The 1,500 industrial firms manufacturing furniture in the Italian Province of Treviso can generate up to 190,000 tonnes of wood wastes annually. In line with the energy conservation-environmental protection measures contained in Italian Law No. 475/88, this paper indicates convenient uses for these wood wastes - as a raw material for fibreboards or as a fuel to be used in the furniture manufacturing plants themselves and in kilns producing lime. Reference is made to the wood wastes gasification/power generation system being developed by ENEA (the Italian Agency for New Technology, Energy and the Environment)

Fire Safety Design of Wood Structures

DEFF Research Database (Denmark)

Hertz, Kristian Dahl

2006-01-01

Lecture Notes on Fire Safety Design of Wood Structures including charring of wood and load bearing capacity of beams, columns, and connections.......Lecture Notes on Fire Safety Design of Wood Structures including charring of wood and load bearing capacity of beams, columns, and connections....

Surface characterization of weathered wood using a laser scanning system

International Nuclear Information System (INIS)

Arnold, M.; Lemaster, R.L.; Dost, W.A.

1992-01-01

Most of the existing methods to assess the effect of weathering on wood surfaces have some drawbacks that limit their use to specific tasks. The amount of surface erosion is often used as a measure for the weathering action. The application of a laser scanning system to reproduce surface profiles and to measure weathering erosion was tested on various samples and was found to be a very useful and superior alternative to existing methods. Further improvements of the system used can be made by refinements of the calibration procedures and by more comprehensive profile analyses. (author)

WOOD BIOMASS FOR ENERGY IN MONTENEGRO

Directory of Open Access Journals (Sweden)

Gradimir Danon

2010-01-01

Full Text Available Wood biomass has got its place in the energy balance of Montenegro. A little more than 6% of the total energy consumption is obtained by burning wood. Along with the appropriate state measures, it is economically and environmentally justified to expect Montenegro to more than double the utilization of the existing renewable energy sources including wood biomass, in the near future. For the purpose of achieving this goal, ‘Commercial Utilisation of the Wood Residue as a Resource for Economic Development in the North of Montenegro' project was carried out in 2007. The results of this project were included in the plan of the necessary interventions of the Government and its Agencies, associations or clusters, non-government organisations and interested enterprises. The plan was made on the basis of the wood residue at disposal and the attitude of individual subjects to produce and/or use solid bio-fuels and consists of a proposal of collection and utilisation of the wood residue for each individual district in the north of Montenegro. The basic factors of sustainability of future commercialisation of the wood residue were: availability of the wood raw material, and thereby the wood residue; the development of wood-based fuel markets, and the size of the profit.

Multi-Scale Thermal Heat Tracer Tests for Characterizing Transport Processes and Flow Channelling in Fractured Media: Theory and Field Experiments

Science.gov (United States)

de La Bernardie, J.; Klepikova, M.; Bour, O.; Le Borgne, T.; Dentz, M.; Guihéneuf, N.; Gerard, M. F.; Lavenant, N.

2017-12-01

The characterization of flow and transport in fractured media is particularly challenging because hydraulic conductivity and transport properties are often strongly dependent on the geometric structure of the fracture surfaces. Here we show how thermal tracer tests may be an excellent complement to conservative solute tracer tests to infer fracture geometry and flow channeling. We performed a series of thermal tracer tests at different scales in a crystalline rock aquifer at the experimental site of Ploemeur (H+ observatory network). The first type of thermal tracer tests are push-pull tracer tests at different scales. The temporal and spatial scaling of heat recovery, measured from thermal breakthrough curves, shows a clear signature of flow channeling. In particular, the late time tailing of heat recovery under channeled flow is shown to diverge from the T(t) α t-1,5 behavior expected for the classical parallel plate model and follow the scaling T(t) α 1/t(logt)2 for a simple channel modeled as a tube. Flow channeling is also manifested on the spatial scaling of heat recovery as flow channeling affects the decay of the thermal breakthrough peak amplitude and the increase of the peak time with scale. The second type of thermal tracer tests are flow-through tracer tests where a pulse of hot water was injected in a fracture isolated by a double straddle packer while pumping at the same flow rate in another fracture at a distance of about 10 meters to create a dipole flow field. Comparison with a solute tracer test performed under the same conditions also present a clear signature of flow channeling. We derive analytical expressions for the retardation and decay of the thermal breakthrough peak amplitude for different fracture geometries and show that the observed differences between thermal and solute breakthrough can be explained only by channelized flow. These results suggest that heat transport is much more sensitive to fracture heterogeneity and flow

Synthesis and characterization of starch-g-poly(vinyl acetate-co-butyl acrylate) bio-based adhesive for wood application.

Science.gov (United States)

Zia-Ud-Din; Chen, Lei; Ullah, Ikram; Wang, Peng Kai; Javaid, Allah Bakhsh; Hu, Chun; Zhang, Mengchao; Ahamd, Ishtiaq; Xiong, Hanguo; Wang, Zhenjiong

2018-07-15

Enhancing the performance of wood adhesive is important for its industrial applications. Accordingly, we designed and demonstrated the use of two co-monomers vinyl acetate (VAc) and butyl acrylate (BA) for promoting the graft copolymerization while improving the bonding performance of wood adhesive. The results showed that the addition of co-monomers in the ratio of VAc/BA 6:4 (v/v, volume basis of VAc) could improve the shear strength to 6.68MPa and 3.32MPa in dry and wet states, respectively. 1 H-nuclear magnetic resonance ( 1 H NMR) and fourier transform infrared spectroscopy (FT-IR) analysis revealed successful graft copolymerization reaction while the morphologies were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Furthermore, the grafting reaction and thermal stabilities of wood adhesive were analyzed by X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). The results showed that the properties of wood adhesive could improve dramatically by using two co-monomers VAc and BA during the graft copolymerization reaction. Copyright © 2018 Elsevier B.V. All rights reserved.

Corrosion of Fasteners in Wood Treated with Newer Wood Preservatives

Science.gov (United States)

Samuel L. Zelinka

2013-01-01

This document compiles recent research findings related to corrosion of metals in preservative treated wood into a single report on corrosion of metals in wood. The research was conducted as part of the Research, Technology and Education portion of the National Historic Covered Bridge Preservation (NHCBP) Program administered by the Federal Highway Administration. The...

Subcritical fracture propagation in rocks: An examination using the methods of fracture mechanics and non-destructive testing. Ph.D. Thesis

Science.gov (United States)

Swanson, P. L.

1984-01-01

An experimental investigation of tensile rock fracture is presented with an emphasis on characterizing time dependent crack growth using the methods of fracture mechanics. Subcritical fracture experiments were performed in moist air on glass and five different rock types at crack velocities using the double torsion technique. The experimental results suggest that subcritical fracture resistance in polycrystals is dominated by microstructural effects. Evidence for gross violations of the assumptions of linear elastic fracture mechanics and double torsion theory was found in the tests on rocks. In an effort to obtain a better understanding of the physical breakdown processes associated with rock fracture, a series of nondestructive evaluation tests were performed during subcritical fracture experiments on glass and granite. Comparison of the observed process zone shape with that expected on the basis of a critical normal principal tensile stress criterion shows that the zone is much more elongated in the crack propagation direction than predicted by the continuum based microcracking model alone.

Rock Springs Site 12 hydraulic/explosive true in situ oil shale fracturing experiment

Energy Technology Data Exchange (ETDEWEB)

Parrish, R.L.; Boade, R.R.; Stevens, A.L.; Long, A. Jr.; Turner, T.F.

1980-06-01

The experiment plan involved the creation and characterization of three horizontal hydraulic fractures, followed by the insertion and simultaneous detonation of slurry explosive in the two lower fractures. Core analyses, wellbore logging, and airflow and /sup 85/Kr tracer tests were used for site characterization and assessment of the hydraulic and explosive fracturing. Tiltmeters, wellhead pressure and flow gages, and in-formation pressure, flow and crack-opening sensors were used to monitor hydrofracture creation and explosive insertion. Explosive detonation diagnostic data were taken with stress and time-of-arrival gages and surface and in-formation accelerometers. The post-fracturing assessments indicated that: (1) hydrofracture creation and explosive insertion and detonation were accomplished essentially as planned; (2) induced fractures were randomly distributed through the shale with no extensively fractured regions or dislocation of shale; and (3) enhancement of permeability was limited to enlargement of the explosive-filled fractures.

Power generation from waste wood

Energy Technology Data Exchange (ETDEWEB)

Nitsche, H

1980-04-18

Since the energy crisis, power generation from waste wood has become increasingly important. The most profitable way to use waste wood in woodworking plants with an annual production of 100 to 150,000 m/sup 3/ solid measure of wood chips and bark is by combustion and thermal energy recovery. In plants with an annual production of 10,000 m/sup 3/ solid measure of wood chips and bark, electric power generation is a suitable application.

On-line Optimization-Based Simulators for Fractured and Non-fractured Reservoirs

Energy Technology Data Exchange (ETDEWEB)

Milind D. Deo

2005-08-31

Oil field development is a multi-million dollar business. Reservoir simulation is often used to guide the field management and development process. Reservoir characterization and geologic modeling tools have become increasingly sophisticated. As a result the geologic models produced are complex. Most reservoirs are fractured to a certain extent. The new geologic characterization methods are making it possible to map features such as faults and fractures, field-wide. Significant progress has been made in being able to predict properties of the faults and of the fractured zones. Traditionally, finite difference methods have been employed in discretizing the domains created by geologic means. For complex geometries, finite-element methods of discretization may be more suitable. Since reservoir simulation is a mature science, some of the advances in numerical methods (linear, nonlinear solvers and parallel computing) have not been fully realized in the implementation of most of the simulators. The purpose of this project was to address some of these issues. {sm_bullet} One of the goals of this project was to develop a series of finite-element simulators to handle problems of complex geometry, including systems containing faults and fractures. {sm_bullet} The idea was to incorporate the most modern computing tools; use of modular object-oriented computer languages, the most sophisticated linear and nonlinear solvers, parallel computing methods and good visualization tools. {sm_bullet} One of the tasks of the project was also to demonstrate the construction of fractures and faults in a reservoir using the available data and to assign properties to these features. {sm_bullet} Once the reservoir model is in place, it is desirable to find the operating conditions, which would provide the best reservoir performance. This can be accomplished by utilization optimization tools and coupling them with reservoir simulation. Optimization-based reservoir simulation was one of the

Characterization and Management of Mandibular Fractures: Lessons Learned from Iraq and Afghanistan

Science.gov (United States)

2013-03-01

interdental splints and intermaxillary fixation.4 Thomas Brian Gunning4 showed the importance of dentistry in treating these fractures by restoring occlusion...Fractures in children with developing dentitionsdAvoiding damage to the developing teeth is key. If placement of arch bars is impossible

Chemical source characterization of residential wood combustion emissions in Denver, Colorado; Bakersfield, California; and Mammoth Lakes, California

International Nuclear Information System (INIS)

Houck, J.E.; Goulet, J.M.; Chow, J.C.; Watson, J.G.

1989-01-01

The chemical composition of residential wood combustion particulate emissions was determined for fireplaces and woodstoves. Burn rates, burn patterns, wood burning appliances, and cordwood types characteristic of Denver, Colorado; Bakersfield, California; and Mammoth Lakes, California, were used during sample collection. Samples were collected using a dilution/cooling system to ensure that condensible compounds were captured. Analyses for 44 chemical species were conducted. Source profiles for use in chemical mass balance (CMB) modeling were calculated from the analytical data. The principal chemical species comprising the profiles were organic compounds and elemental carbon. The minor chemical species were sulfur, chlorine, potassium, sodium, calcium, zinc, nitrate, and ammonium. Virtually all potassium was in a water-soluble form, and sulfur emissions between fireplaces and woodstoves were noted. Area-specific source profiles for fireplaces, woodstoves, and overall residential wood combustion are presented

The Fracture Process of Tempered Soda-Lime-Silica Glass

DEFF Research Database (Denmark)

Nielsen, Jens Henrik; Olesen, John Forbes; Stang, Henrik

2009-01-01

This work presents experimental observations of the characteristic fracture process of tempered glass. Square specimens with a side length of 300 mm, various thicknesses and a residual stress state characterized by photoelastic measurements were used. Fracture was initiated using a 2.5 mm diamond...

Status of wood energy applications

International Nuclear Information System (INIS)

Zerbe, J.I.

1991-01-01

In this address, the potential of wood and wood residues to supply future energy needs is examined. In addition, the possible environmental impact of the use of wood fuels on global climate change is discussed. Technologies for the development of new fuels are described

Choosing Wood Burning Appliances

Science.gov (United States)

Information to assist consumers in choosing a wood burning appliance, including types of appliances, the differences between certified and non-certified appliances, and alternative wood heating options.

Characterization of EGS Fracture Network Lifecycles

Energy Technology Data Exchange (ETDEWEB)

Gillian R. Foulger

2008-03-31

Geothermal energy is relatively clean, and is an important non-hydrocarbon source of energy. It can potentially reduce our dependence on fossil fuels and contribute to reduction in carbon emissions. High-temperature geothermal areas can be used for electricity generation if they contain permeable reservoirs of hot water or steam that can be extracted. The biggest challenge to achieving the full potential of the nation’s resources of this kind is maintaining and creating the fracture networks required for the circulation, heating, and extraction of hot fluids. The fundamental objective of the present research was to understand how fracture networks are created in hydraulic borehole injection experiments, and how they subsequently evolve. When high-pressure fluids are injected into boreholes in geothermal areas, they flow into hot rock at depth inducing thermal cracking and activating critically stressed pre-existing faults. This causes earthquake activity which, if monitored, can provide information on the locations of the cracks formed, their time-development and the type of cracking underway, e.g., whether shear movement on faults occurred or whether cracks opened up. Ultimately it may be possible to monitor the critical earthquake parameters in near-real-time so the information can be used to guide the hydraulic injection while it is in progress, e.g., how to adjust factors such as injectate pressure, volume and temperature. In order to achieve this, it is necessary to mature analysis techniques and software that were, at the start of this project, in an embryonic developmental state. Task 1 of the present project was to develop state-of-the-art techniques and software for calculating highly accurate earthquake locations, earthquake source mechanisms (moment tensors) and temporal changes in reservoir structure. Task 2 was to apply the new techniques to hydrofracturing (Enhanced Geothermal Systems, or “EGS”) experiments performed at the Coso geothermal field

Bacterial Community Succession in Pine-Wood Decomposition.

Science.gov (United States)

Kielak, Anna M; Scheublin, Tanja R; Mendes, Lucas W; van Veen, Johannes A; Kuramae, Eiko E

2016-01-01

Though bacteria and fungi are common inhabitants of decaying wood, little is known about the relationship between bacterial and fungal community dynamics during natural wood decay. Based on previous studies involving inoculated wood blocks, strong fungal selection on bacteria abundance and community composition was expected to occur during natural wood decay. Here, we focused on bacterial and fungal community compositions in pine wood samples collected from dead trees in different stages of decomposition. We showed that bacterial communities undergo less drastic changes than fungal communities during wood decay. Furthermore, we found that bacterial community assembly was a stochastic process at initial stage of wood decay and became more deterministic in later stages, likely due to environmental factors. Moreover, composition of bacterial communities did not respond to the changes in the major fungal species present in the wood but rather to the stage of decay reflected by the wood density. We concluded that the shifts in the bacterial communities were a result of the changes in wood properties during decomposition and largely independent of the composition of the wood-decaying fungal communities.

Wood power in North Carolina

Energy Technology Data Exchange (ETDEWEB)

Cleland, J.G.; Guessous, L. [Research Triangle Institute, Research Triangle Park, NC (United States)

1993-12-31

North Carolina (NC) is one of the most forested states, and supports a major wood products industry. The NC Department of Natural Resources sponsored a study by Research Triangle Institute to examine new, productive uses of the State`s wood resources, especially electric power generation by co-firing with coal. This paper summarizes our research of the main factors influencing wood power generation opportunities, i.e., (1) electricity demand; (2) initiative and experience of developers; (3) available fuel resources; (4) incentives for alternate fuels; and (5) power plant technology and economics. The results cover NC forests, short rotation woody crops, existing wood energy facilities, electrical power requirements, and environmental regulations/incentives. Quantitative assessments are based on the interests of government agencies, utilities, electric cooperatives, developers and independent power producers, forest products industries, and the general public. Several specific, new opportunities for wood-to-electricity in the State are identified and described. Comparisons are made with nationwide resources and wood energy operations. Preferred approaches in NC are co-generation in existing or modified boilers and in dedicated wood power plants in forest industry regions. Co-firing is mainly an option for supplementing unreliable primary fuel supplies to existing boilers.

The Carbon Impacts of Wood Products

Science.gov (United States)

Richard Bergman; Maureen Puettmann; Adam Taylor; Kenneth E. Skog

2014-01-01

Wood products have many environmental advantages over nonwood alternatives. Documenting and publicizing these merits helps the future competitiveness of wood when climate change impacts are being considered. The manufacture of wood products requires less fossil fuel than nonwood alternative building materials such as concrete, metals, or plastics. By nature, wood is...

The influence of irradiated wood filler on some properties of polypropylene - wood composites

Directory of Open Access Journals (Sweden)

Điporović-Momčilović Milanka

2007-01-01

Full Text Available The problem of compatibility between the wood filler and thermoplastic matrix is of essential importance in composite production. Numerous methods have been developed for increasing this compatibility, which is still representing a challenging objective of composite research throughout the world. The research into these methods is primarily directed towards their efficiency from the viewpoint of the composite performance and their economical acceptability. The latter is of particular importance for the composite production in the developing countries with respect to the shortage of the corresponding funds. With this respect, the utilization of ionizing radiation might have considerable advantages. In this research, the beech wood flour was irradiated by a dose of 10 kGy of 60Co gamma rays for purpose of provoking the changes by the ionizing effect. The effects of ionizing radiation upon the properties of wood particles have been examined by IR spectroscopy and by determination of contents of hydroxyl groups in wood by acetylating as an indirect method. All these methods have been expected to reveal the chemical effects of the applied radiation treatment. The irradiated and the control wood flour were used in order to produce the samples of composite with polypropylene. The polypropylene-wood flour (PP-WF composites were produced with 40% of wood particles having fraction size 0.3 mm. The melt-blended composites were modified with amido-acrylic acid (AMACA as a new coupling agent synthesized for this propose in amount of 6 wt.% (based on wood filler and successively with 0.05 wt.% (based on PP of organic peroxide during mixing step. The composites containing coupling agents showed superior mechanical properties, compared to the untreated one. The highest extent of improvement of tensile was achieved in PP-WFl composites modified with AMACA coupling agent.

Methane from wood

Energy Technology Data Exchange (ETDEWEB)

Schulz, T. F.; Barreto, L.; Kypreos, S.; Stucki, S

2005-07-15

The role of wood-based energy technologies in the Swiss energy system in the long-term is examined using the energy-system Swiss MARKAL model. The Swiss MARKAL model is a 'bottom-up' energy-systems optimization model that allows a detailed representation of energy technologies. The model has been developed as a joint effort between the Energy Economics Group (EEG) at Paul Scherrer Institute PSI) and the University of Geneva and is currently used at PSI-EEG. Using the Swiss MARKAL model, this study examines the conditions under which wood-based energy technologies could play a role in the Swiss energy system, the most attractive pathways for their use and the policy measures that could support them. Given the involvement of PSI in the ECOGAS project, especial emphasis is put on the production of bio-SNG from wood via gasification and methanation of syngas and on hydrothermal gasification of woody biomass. Of specific interest as weIl is the fraction of fuel used in passenger cars that could be produced by locally harvested wood. The report is organized as follows: Section 2 presents a brief description of the MARKAL model. Section 3 describes the results of the base case scenario, which represents a plausible, 'middle-of-the-road' development of the Swiss energy system. Section 4 discusses results illustrating the conditions under which the wood-based methanation technology could become competitive in the Swiss energy market, the role of oil and gas prices, subsidies to methanation technologies and the introduction of a competing technology, namely the wood-based Fischer-Tropsch synthesis. FinaIly, section 5 outlines some conclusions from this analysis. (author)

Methane from wood

International Nuclear Information System (INIS)

Schulz, T. F.; Barreto, L.; Kypreos, S.; Stucki, S.

2005-07-01

The role of wood-based energy technologies in the Swiss energy system in the long-term is examined using the energy-system Swiss MARKAL model. The Swiss MARKAL model is a 'bottom-up' energy-systems optimization model that allows a detailed representation of energy technologies. The model has been developed as a joint effort between the Energy Economics Group (EEG) at Paul Scherrer Institute PSI) and the University of Geneva and is currently used at PSI-EEG. Using the Swiss MARKAL model, this study examines the conditions under which wood-based energy technologies could play a role in the Swiss energy system, the most attractive pathways for their use and the policy measures that could support them. Given the involvement of PSI in the ECOGAS project, especial emphasis is put on the production of bio-SNG from wood via gasification and methanation of syngas and on hydrothermal gasification of woody biomass. Of specific interest as weIl is the fraction of fuel used in passenger cars that could be produced by locally harvested wood. The report is organized as follows: Section 2 presents a brief description of the MARKAL model. Section 3 describes the results of the base case scenario, which represents a plausible, 'middle-of-the-road' development of the Swiss energy system. Section 4 discusses results illustrating the conditions under which the wood-based methanation technology could become competitive in the Swiss energy market, the role of oil and gas prices, subsidies to methanation technologies and the introduction of a competing technology, namely the wood-based Fischer-Tropsch synthesis. FinaIly, section 5 outlines some conclusions from this analysis. (author)

Temperature effects on wood anatomy, wood density, photosynthesis and biomass partitioning of Eucalyptus grandis seedlings.

Science.gov (United States)

Thomas, D S; Montagu, K D; Conroy, J P

2007-02-01

Wood density, a gross measure of wood mass relative to wood volume, is important in our understanding of stem volume growth, carbon sequestration and leaf water supply. Disproportionate changes in the ratio of wood mass to volume may occur at the level of the whole stem or the individual cell. In general, there is a positive relationship between temperature and wood density of eucalypts, although this relationship has broken down in recent years with wood density decreasing as global temperatures have risen. To determine the anatomical causes of the effects of temperature on wood density, Eucalyptus grandis W. Hill ex Maiden seedlings were grown in controlled-environment cabinets at constant temperatures from 10 to 35 degrees C. The 20% increase in wood density of E. grandis seedlings grown at the higher temperatures was variously related to a 40% reduction in lumen area of xylem vessels, a 10% reduction in the lumen area of fiber cells and a 10% increase in fiber cell wall thickness. The changes in cell wall characteristics could be considered analogous to changes in carbon supply. Lumen area of fiber cells declined because of reduced fiber cell expansion and increased fiber cell wall thickening. Fiber cell wall thickness was positively related to canopy CO2 assimilation rate (Ac), which increased 26-fold because of a 24-fold increase in leaf area and a doubling in leaf CO2 assimilation rate from minima at 10 and 35 degrees C to maxima at 25 and 30 degrees C. Increased Ac increased seedling volume, biomass and wood density; but increased wood density was also related to a shift in partitioning of seedling biomass from roots to stems as temperature increased.

Femoral neck fractures complicating gaucher disease in children